The sustainability of producing BTX from biomass

University of Groningen
CIO, Center for Isotope Research
IVEM, Center for Energy and Environmental Studies
Master Programme Energy and Environmental Sciences
The sustainability of producing
BTX from biomass
Anne Meuwese
EES 2013-165 M

Master report of Anne Meuwese
Supervised by: Dr. N. Schenk (KNN advies b.v.)
Prof.dr. H.C. Moll (IVEM)
Prof.dr. A.J.M. Schoot Uiterkamp (IVEM)
University of Groningen
CIO, Center for Isotope Research
IVEM, Center for Energy and Environmental Studies
Nijenborgh 4
9747 AG Groningen
The Netherlands
http://www.rug.nl/fmns-research/cio
http://www.rug.nl/fmns-research/ivem

Acknowledgements
I would first of all like to thank my supervisor at KNN advies b.v. Dr Niels Schenk for his support
throughout the process, his enthusiasm for my research and his confidence inspiring confidence. His
no-nonsense mentality combined with optimism and a kind hart have greatly aided the progress of
my research.
Secondly, I would like to thank Professor Henk Moll for his insights and advice, without which I would
have undoubtedly struggled more with this complex approach to LCA.
I am once again indebted to Professor Ton Schoot Uiterkamp for his determination to make me a
better researcher and his passion to inspire those around him to strive for a better world.
Last but not least I would like to thank my colleagues at KNN, especially my boss Dr Cor Kamminga,
who provided an energetic workplace with interesting discussions and a pleasant atmosphere that
made time fly by.

Summary
The dependence of humans on fossil resources is not limited to fuel needs. A significant amount of
petroleum feedstock is also used to produce materials, from pharmaceuticals and plastics to asphalt
for roads. But just like with fuels, the use of fossil resources for these purposes leads to depletion of
resources and greenhouse gas emissions.
Benzene, toluene and the three xylenes (BTX) are bulk chemicals which are vital for the
petrochemical industry. Their major downstream products are plastics, but they are also used for
solvents, additives and other specialty chemicals. Based on the environmental impacts over the
lifecycle of a BTX product, the fossil resource depletion and greenhouse gas emissions make the
largest impact on the environment. Because of this and the size of the market for BTX products, it is
important to look for more sustainable options for BTX.
One of these options is producing BTX from biomass rather than from fossil resources. A relatively
new focus of research, the process is not yet commercial, but it does have the potential to be. Using
woody biomass as a feedstock, yields of around 15% are already reached. Woody biomass is
preferable, both for product yield but also because using woody biomass is often more sustainable
than using starch and oil crops. Compared to the fossil-based process, the fossil resource inputs and
CO2 emissions are low, so based on those two parameters biomass-based BTX promises to be a
sustainable option. The main question of this research was: Is production of BTX from biomass a
sustainable use of the resource, considering system efficiency and macro scale effects?
Since the amounts of woody or sustainable biomass available at a certain time are limited, other
products from this biomass were also researched, to determine whether the environmental impact
of producing BTX was lower than that of other products. Three product categories were chosen,
electricity, fuel and materials, to represent a spectrum of products from woody biomass. For fuel
products, both ethanol and biomass-based diesel were taken into account. For materials, ethylene,
BTX, and two compounds for polyethylene polymer production. The latter two were terephthalic acid
(TA, product of BTX) and a sugar based alternative for TA, furandicarboxyllic acid (FDCA), which can
be produced well from corn and in theory from wood.
Subsequently, the fossil resource inputs and CO2 outputs of the biomass- and fossil-based processes
for each of these products were calculated. It was concluded that diesel and BTX were more
sustainable uses of biomass than ethanol, ethylene and electricity. Comparing the in- and outputs of
the production of biomass-based FDCA with the production of biomass-based terephthalic acid (TA,
product of BTX), it was concluded that FDCA from corn had lower emissions and fossil resource
requirements than TA from wood, but that FDCA from wood performed poorly.
Finally, several macro effects were examined: waste stream use, other renewable resource potential,
petrochemical industry trends, recycling- and cascading-potential and scale effects. Biomass-based
BTX can use waste streams, does not have another renewable alternative and, will probably be more
attractive in the future based on market trends. Since it is a material, there is possibility of recycling
and cascading. For the other products concerned, the macro effects were either not positive or less
so than for biomass-based BTX.
Therefore, based on fossil resource use, CO2 emissions and several macro scale effects, it can
concluded that producing BTX from biomass is a sustainable use of the resource.

Samenvatting
De mensheid is niet alleen voor brandstof afhankelijk van fossiele grondstoffen. Een significant deel
van de fossiele grondstoffen wordt gebruikt voor de productie van materialen, van medicijnen tot
plastics tot teer. Maar net als bij brandstoffen is er bij het gebruik van fossiele grondstoffen voor
deze doeleinden een verband met oprakende reserves en de emissie van broeikasgassen, die op hun
beurt weer een verband hebben met klimaatverandering.
Benzeen, tolueen en de drie xylenen (BTX) zijn bulkchemicaliën met een vitale rol in de olie industrie.
De belangrijkste producten die uit BTX gemaakt worden zijn plastics, maar BTX wordt ook gebruikt
als uitgangsstof voor oplosmiddelen, additieven en andere (fijn)chemicaliën. De belangrijkste milieu
effecten van een plastic gemaakt van benzeen over zijn hele levenscyclus zijn het grondstof gebruik
en de emissie van broeikasgassen. Gezien de grootte van de markt voor BTX producten, is het
relevant om te kijken naar duurzame alternatieven voor de traditionele BTX.
Een van deze alternatieven is het produceren van BTX uit biomassa in plaats van uit fossiele
grondstoffen. Dit is een relatief nieuwe technologie die nog niet op commerciële schaal wordt
toegepast, terwijl dit wel mogelijk zou zijn. Met hout als grondstof worden al omzettingen van 15%
op basis van massa gehaald. Hout is een betere grondstof voor dit soort proces dan olie- of
zetmeelgewassen, zowel omdat de opbrengst hoger is en omdat hout vaak milieuvriendelijker wordt
geproduceerd dan langbouwgewassen. BTX productie uit hout heeft een lager fossiel grondstof
gebruik en minder CO2 emissies dan BTX productie uit fossiele grondstoffen, en is dus wat dat betreft
duurzamer. Het doel van dit onderzoek was uitvinden of BTX uit biomassa duurzaam gebruik van
deze grondstof was.
Aangezien er maar een beperkte hoeveelheid duurzame biomassa beschikbaar is per jaar werd in dit
onderzoek ook gekeken naar de duurzaamheid van alternatieve producten uit biomassa. Daarmee
kon worden bepaald wat de relatieve duurzaamheid van BTX productie is in vergelijking met andere
biomassa producten. Er werd gekeken naar drie productgroepen: elektriciteit, brandstof en
materialen. Voor brandstof werden bioethanol en biodiesel uit hout bekeken, voor materialen
ethyleen uit hout en een suiker-gebaseerd alternatief voor het plastic PET, FDCA. De laatste kan uit
zowel hout als mais worden gemaakt.
Voor al deze producten werd voor zowel het fossiele als het biomassa proces de CO2 emissies en
fossiel brandstof gebruik uitgerekend. Gebaseerd op deze berekeningen kon worden geconcludeerd
dat BTX en diesel de meest duurzame producten uit hout waren. Het maken van FDCA uit mais had
lagere emissies en grondstof gebruik dan het maken van PET uit hout, FDCA uit hout deed het het
slechtst. FDCA productie uit mais is echter minder duurzaam, omdat mais ook een belangrijke
voedselbron is en dus in de eerste plaats zou moeten worden gebruikt om voedselschaarste tegen te
gaan.
Als laatste werd gekeken naar verscheidene macro-effecten: de mogelijkheden om afvalstromen te
gebruiken en om te recyclen, trends in de petrochemie, alternatieve hernieuwbare bronnen en
opschaalbaarheid. Daar waar een waardeoordeel viel te vormen, kwam BTX altijd het beste uit de
analyse.
Op basis van het fossiele grondstof verbruik, de CO2 uitstoot en verscheidene macro-effecten kan
worden geconcludeerd dat BTX uit biomassa een duurzaam gebruik van deze grondstof is.

List of abbreviations
BTX Benzene, toluene and xylenes
FDCA Furandicarboxylic acid
HHV Higher heating value
HMF hydroxymethylfurfural
ILUC Indirect land use change
LCA Life cycle analysis
PEF Polyethylene furandicarboxylate
PET Polyethylene terephthalate
PLA Polylactic acid
PTA Purified terephthalic acid
TA Terephthalic acid

Contents
Acknowledgements ...................................................................................................................... 1
Summary ..................................................................................................................................... 3
Samenvatting ............................................................................................................................... 4
List of abbreviations ..................................................................................................................... 5
1 Introduction .............................................................................................................................. 9
1.1 Background .................................................................................................................................... 9
1.2 Research aim and questions ........................................................................................................ 11
1.3 Sustainability ............................................................................................................................... 12
1.4 Scope ........................................................................................................................................... 12
1.5 Methods ...................................................................................................................................... 12
2.0 Fossil-based BTX ................................................................................................................... 13
2.1 introduction ................................................................................................................................. 13
2.2 Life cycle analysis of fossil-based BTX ......................................................................................... 14
2.3 Alternatives to fossil-based BTX .................................................................................................. 16
3.0 Biomass-based BTX ............................................................................................................... 17
3.1 Research towards biomass-based BTX ........................................................................................ 17
3.2 Advantages and disadvantage ..................................................................................................... 18
4 Alternative biomass use ........................................................................................................... 19
4.1 Choice of biomass ........................................................................................................................ 19
4.2 Uses of lignocellulosic biomass ................................................................................................... 19
5 LCA and functional units .......................................................................................................... 21
5.1 Set-up of the life cycle analysis ................................................................................................... 21
5.2 Choice of processes for the functional units ............................................................................... 21
5.3 Formulation of the functional unit .............................................................................................. 22
5.4 System boundaries ...................................................................................................................... 23
6 LCA of biomass-based FDCA and TA production ........................................................................ 27
6.1 Inventory ..................................................................................................................................... 27
6.2 Method ........................................................................................................................................ 27
6.3 Results ......................................................................................................................................... 27
6.4 Inventory discussion .................................................................................................................... 30
7.0 Biomass versus fossil LCA ...................................................................................................... 31
7.1 Inventory ..................................................................................................................................... 31
7.2 Methods ...................................................................................................................................... 32

7.3 Results ......................................................................................................................................... 33
7.4 Inventory discussion .................................................................................................................... 35
8.0 Discussion LCA results ........................................................................................................... 39
8.1 Outcome of the LCA’s .................................................................................................................. 39
8.2 Correlation in the margins ........................................................................................................... 39
8.3 Electricity differences .................................................................................................................. 39
9.0 Macro scale effects ............................................................................................................... 41
9.1 Using waste streams as feedstock............................................................................................... 41
9.2 Future trends in the petroleum market ...................................................................................... 42
9.3 Renewable alternatives ............................................................................................................... 43
9.4 Corn as a feedstock ..................................................................................................................... 43
9.5 Cascading and recycling............................................................................................................... 44
9.6 Scale potential ............................................................................................................................. 45
9.7 Conclusion ................................................................................................................................... 46
10 Discussion ............................................................................................................................. 49
10.1 General discussion ..................................................................................................................... 49
10.2 Comparison with other research ............................................................................................... 50
11 Conclusion ............................................................................................................................. 53
12 References ............................................................................................................................ 55
Appendix A: LCA polystyrene cup ................................................................................................ 61
Appendix B: inventories ............................................................................................................. 62
Detailed inventory of chapter 6 ........................................................................................................ 62
Detailed inventory chapter 7 ............................................................................................................. 65
Appendix C: Uncertainty determination ...................................................................................... 71
Appendix D: Sensitivity chapter 6 ............................................................................................... 73
Appendix E: Sensitivity chapter 7 ................................................................................................ 75

1 Introduction
This research concerns determining the sustainability of producing the chemicals benzene, toluene
and the three xylenes (BTX) from biomass instead of fossil resources. BTX is produced on mega ton
scale globally, but the non-renewable nature of its feedstocks may pose a problem in the long term.
Producing BTX from biomass is attractive, since there is a potential to mitigate carbon emissions on a
large scale. However, since the amount of renewable biomass is limited, it is possible that it could be
used more efficiently for other purposes than BTX production. Additionally, the production of
biomass-based BTX could have a larger impact on the environment than fossil-based BTX production.
A comprehensive life cycle analysis was used to determine which BTX production method is most
sustainable and what the relative sustainability of biomass-based BTX is compared to other biomass
products.
1.1 Background
The dependence of industrialized countries on fossil resources is not limited to their fuel needs: a
substantial amount of the materials used on a day to day basis is also derived from non-renewable
sources (Langeveld, 2010). The petroleum industry and its secondary and tertiary industries produce
chemicals ranging from bulk polymers to highly specialized pharmaceuticals. But the emission of CO2
from the use of fossil carbon sources is associated with climate change, and alternatives will have to
be found as supplies of available fossil carbon can run out.
1.1.1 BTX
The aromatic compounds benzene, toluene and the xylenes (meta, para and ortho) are often
grouped together as BTX (US DOE, 2000). They are part of the six major platform chemicals (along
with ethylene, propylene and butadiene), and form the basis for the production of a whole array of
bulk chemicals, as shown in figure 1 (Blaauw, 2008).
Figure 1: Major products derived from BTX (after (US DOE, 2012))
In the Netherlands alone, BTX production is about 3,3 Mt annually, accounting for about 3% of global
production of BTX. BTX is currently most often produced by the catalytic cracking of the naphtha
fraction of crude oil, although production from pyrolysis gas and from coal is also significant
(Sweeney, 2008). The demand for the different chemicals within the BTX group is 67:5:28
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espectively, although no process directly gives this ratio. Therefore, toluene is often converted into
benzene and xylene to adjust the ratios.
1.1.2 Negative impacts of BTX
BTX has an environmental impact due to the fact that it is produced from fossil resources in an
energy intensive process. Although compared to fuel production, chemicals production is a small
sector, the non-renewable nature of crude oil will limit its use in the future (Blaauw, 2008). The use
of fossil BTX will eventually lead to fossil carbon dioxide ending up in the environment, which is
associated with climate change, although the timeframe depends on the application and the waste
processing. Aside from these direct emissions, fossil carbon dioxide is also emitted in the production
process because of the energy requirements, along with emissions of, for example, NOx and SOx
(Wang, 2008). BTX production accounted for 3.5% of the CO2 emissions of the chemical industry in
Europe in 2009 (Benner, 2012).
1.1.3 Biomass as an alternative for fossil resources
One way of decreasing the environmental impact of BTX production is to use biomass as a feedstock
instead of crude oil. In general, biomass can be used as a feedstock for a multitude of applications:
electricity production, heat production and the production of compounds ranging from combustion
fuels to pharmaceuticals. Currently dominant uses of biomass are so called 1 st generation fuels and
electricity and heat production. First generation biofuels are mostly made from agricultural crops
such as corn and sugar cane but also from oil crops (Naik, 2010). Although they can be processed into
ethanol and bio-diesel, the largest drawbacks to these crops are that they are competing with food
production and require fertilizers and pesticides in large quantities, which decreases their
environmental friendliness. Although second generation fuels are more sustainable since they are
based on biomass waste streams, producing higher value products than fuels from biomass is
preferable because it makes more efficient use of the limited available renewable biomass. So called
“biorefineries” aim to mimic the petrochemical industry and design processes that make a whole
range of products from biomass, since process integration will benefit the cost and resource
efficiency (Bozell, 2008; Willems, 2009).
1.1.4 Production of BTX from biomass
BTX is an interesting use of biomass in an economic sense, since there is a large market which can be
tapped into by biomass-derived BTX. Unlike new biochemicals, for which a whole new market needs
to be created, BTX from biomass can be used as a direct replacement of BTX from fossil sources. The
perspective of biomass-based BTX depends thus only on its production cost and the
impact/requirements of production. The production of BTX from biomass can follow several routes. A
useful feedstock for biochemicals is lignocellulosic biomass, which originates from woody plants.
Since part of the molecules therein contain aromatic structures, techniques like liquefaction can
extract these aromatic compounds without completely fragmenting them first (Holladay, 2007).
Alternatively, the aromatic compounds can be synthesized from other molecules derived from
biomass (Williams, 2012). In some cases, like catalytic pyrolysis, the mechanism with which the BTX
are formed is not clear, since they can be both formed during the high temperature reaction or
simply result from fragmenting larger structures.
1.1.5 Advantages and disadvantages of biomass based BTX
Advantages of making BTX from biomass are the renewable nature of biomass, and the fact that
polymers made from biomass derived BTX would be a CO2 sink (Bergsma, 2010). However, the
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process of making biomass derived BTX is still in its infancy, whilst the fossil derived BTX production
is a decade’s old process which has thus been optimized. Therefore, biomass derived BTX production
could require more energy and resources than fossil BTX, possibly offsetting its environmental
benefits. In order for BTX production from biomass to be sustainable, the benefits must outweigh
these costs and also be comparable or better than other uses of the biomass in terms of
sustainability.
1.1.6 Life Cycle Analysis
Life Cycle Analysis (LCA) is a method to determine what the impacts of producing, using and
disposing of a certain product or service is (Finnveden, 2009). Since for this research the impacts of
the whole chain are interesting, it is a suitable method of determining the environmental impact.
There are two main categories of LCA: attributal or descriptive LCA and consequential or choice
based LCA. Attributal LCA is used when a detailed analysis of the physical flows in a single process,
while consequential LCA is used to determine which choice between, for example, feedstocks will
result in a lower environmental impact.
1.1.7 Larger scale problems
Products from biomass usually work well on small scale, but when implemented on large scale can
cause more harm than good (Hipolito, 2011). Since BTX is such an important and large scale product
nowadays, there is a risk that biomass based BTX could become such a large scale commodity that it
outgrows its sustainability, for example when biomass based BTX production competes with food
production and biodiversity.
1.2 Research aim and questions
This research therefore aims to compare the environmental impact of biomass-based BTX production
with several fossil and biomass-based processes to determine which use of biomass would yield the
largest environmental gains. Aside from this, the macro effects of production biomass derived BTX
will be determined to see if there are significant large scale and long term effects.
Given the research aim, the main research question was:
Is production of BTX from biomass a sustainable use of the resource, considering system efficiency
and macro scale effects?
To answer this question, first the functions of BTX in meeting societal needs were determined, to see
if those functions can be fulfilled by renewable/more sustainable alternatives. Then the different
routes to BTX from biomass were determined. Next, alternative uses of lignocellulose biomass were
identified. Since these were very widespread, they were categorized into several utilities. With the
BTX route and alternative use routes determined, a functional unit for the life cycle analysis was
formed. With these LCA’s, the fossil resource use savings and CO2 emission savings were determined.
Lastly, macro effects of the use of biomass derived BTX and trends in the considered processes were
identified, to assess the effect on the sustainability of the systems.
The research is thus divided into the following sub questions:
1) What are the functions of BTX, and what alternatives are there? (chapter 2)
2) What pathways to BTX from biomass are there? (chapter 3)
3) What are other significant uses of lignocellulosic biomass? (chapter 4)
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4) What are the environmental impacts of biomass-based BTX compared to fossil-based BTX?
(chapter 7)
5) What are the environmental impacts of biomass-based BTX compared to other uses of
biomass? (chapter 6 & 7)
6) What are the macro effects of (biomass-based) BTX production? (chapter 9)
1.3 Sustainability
In the broadest sense, sustainability is about maintaining a certain status quo, in the environmental
sense it is about humanity and nature living in such a harmony that resources are not depleted, the
environment is not polluted. A social factor is included by defining sustainability as “meeting the
needs of the present without compromising the ability of future generation to meet their own
needs” (Brundtland Commission, 1987). In this research, “sustainable” is defined as being the most
accommodating to accomplishing the goal of a sustainable society. So a process can be considered
sustainable even if it does use a non-renewable feedstock, as long as overall its environmental
impact is lower than that of other processes that it can/has to be substituted with. It is assumed that
the demand in society for a service is not modifiable, although in practice efficiency increase and
reducing demand are options. But in the absence of abstaining from using a product, producing this
product with a lower environmental impact is considered sustainable. Aside from looking at “micro”effects
such as the CO2-emissions of producing one kilogram of product, which give limited
information about the overall sustainability of a product, the macro-effects of production are also
considered. With both micro- and macro-effects, a general assessment of the sustainability of the
products under consideration can be given.
1.4 Scope
For the first five research questions, the geographic scope was not defined, although within the
inventory phase of the LCA the Netherlands/Europe was used in the process wherever choices had to
be made in the inventory phase of the LCA. For the sixth research question, the scale was global,
since at this scale the use of biomass has the largest risk of becoming problematic. The time scale for
the sixth research question is up until 2030, since that gives some time to develop technology but it
is sufficiently near for information and outlooks to be available at that time period.
1.5 Methods
The first three sub questions relied on literature research, from scientific journals and where
necessary from commercial or government resources. Scientific articles were searched for in the
Scopus database.
For the fourth and fifth research questions, LCA schemes were developed based on the results of the
first three research questions. Based on these scenarios, a functional unit was defined. The different
routes in the scenarios were inventoried using the Ecoinvent v 2.2 database and, where necessary,
alternative sources. With the inventory in place, the scenarios were calculated, so a comparison
could be made between environmental impacts. These calculations were performed using excel
rather than a modelling program like SimaPro, since this was a customized LCA.
For the study of the macro effects, literature and simple models/calculations were used.

2.0 Fossil-based BTX
In this chapter the uses, impacts and alternatives to BTX are explored.
2.1 introduction
Benzene, toluene and the three xylenes are aromatic hydrocarbons produced in very large volumes
worldwide (Sweeney, 2008). Figure 2 shows the molecular structure of the 5 compounds. Although
their structure is of importance to their function in chemistry, for this report it is sufficient to note
that they are relatively simple structures that are very similar.
Figure 2: molecular structures of a) benzene; b) toluene; c) ortho-xylene; d) meta-xylene; e) para-xylene
Benzene, toluene and xylene are “platform chemicals”: basic chemical compounds that are used as a
starting point for a whole range of other compounds. Annual production is around 60 Mt, prices
range between 0.52 and 0.86 euro per litre (Sweeney, 2008; ICIS, 2012).
Figure 3 shows the main uses of BTX. Benzene is the highest in demand among BTX. Ethyl benzene
and subsequent (poly) styrene production is the major use of benzene. Other important downstream
products are phenolic compounds, acetone and nylon-6 (US DOE, 2000). Benzene itself is being
phased out as an end stream product (solvent) since it is carcinogenic.
Toluene is used as a solvent and a precursor for polyurethane production. The market for toluene
and its products is relatively small. Since toluene is produced in a larger amount than needed during
BTX production, a large part of the produced toluene is hydrodealkylated to form benzene (also
works with xylene) or disproportionated to form benzene and xylene (Benner, 2012).
Within the xylenes, meta-xylene is used relatively little. Ortho-xylene has some precursor and
additive uses, but para-xylene has the largest market, since it is a precursor for polyethylene
terephthalate (PET) and high end polymer applications such as aramid fibers (Kroschwitz, 2004).
BTX is produced commercially in three main ways: from reformate, from steam-cracking naphta and
by coal pyrolysis. (Sweeney, 2008) Reformate is a mixture of hydrocarbons that has been produced
by heating a light fraction of crude oil in the presence of a catalyst, with the goal of producing
transport fuel. BTX is part of this reformate, and can be extracted from the mixture. Steam-cracking
of naphta is used to produce ethylene (another platform chemical), and has BTX as a by-product.
Lastly, pyrolysis of coal also produces BTX, and was in fact the first commercially used process for BTX
production. Although it has been out of favour, BTX production from coal is on the rise again with the
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shrinking resources of crude oil. Aside from these three ways, there are several other processes, for
example the catalytic conversion of methanol to BTX. The attractiveness of each route depends on
the economic situation of both the feedstock and BTX (products), and production is therefore not
constant (Sweeney, 2008).
Figure 3: BTX production chain (from (US DOE, 2000))
Reformate and naphtha cracking are the main sources of BTX globally. Regionally the ratio varies
depending on what other industry is present. Since BTX is not only used as a chemical but is also
useful as a fuel additive, prices and demand relies partly on the global demand and supply of fuel.
Additionally, BTX prices depend on downstream demands and supplies. In 2010, a rise in the price of
cotton caused an increased demand in synthetic fibres and therefore in benzene and xylene (PPE,
2011). The dependence of BTX supply and demand on so many factors is a clear sign that it is a vital
part of the global economy. Therefore the sustainability of BTX is an important part of the
sustainability of society.
2.2 Life cycle analysis of fossil-based BTX
As mentioned in the previous paragraph, benzene is a carcinogenic compound, to such an extent that
its use is limited to avoid needless exposure. But the production and use of BTX has other impacts,
and in order to determine where improvements on the sustainability of BTX could be made, all of
them should be mapped.
A previous study looked at the production of polystyrene packaging material (compared to a
biomass-based alternative) and showed that among all impacts the impact of carcinogenic
substances was the smallest (Zabaniotou & Kassidi, 2003). Other impacts, such as acidification
potential and global warming potential were more important.
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To expand on those results, a compact life cycle assessment of a polystyrene cup was modelled in
SimaPro with the Ecoinvent v2.2 database. It was assumed that cup was made by injection moulding,
that the use phase consisted only of transport and that the waste phase was in common domestic
waste disposal in the Netherlands. For more details, see appendix A.
Figure 4 shows the normalized impact categories for the life cycle of the polystyrene cup. The first
column shows the normalized impacts of the production of the cup, the second the use phase in
which the cup is transported 500 km, the last column shows the waste phase. The production of the
cup has the largest impact, and this is due to fossil resource depletion and climate change. The use
phase has a small impact, although again fossil resource use and climate change are the important
impact categories. The waste phase also has some impact; the relevant categories there are climate
change (due to the release of fossil carbon from which the polystyrene cup is made) but also human
toxicity.
Figure 4: Normalized impact categories LCA polystyrene cup
Again the carcinogenic impact (human toxicity) is shown to be small, although it is the fourth largest
impact, the carcinogenetic of benzene is thus not the characteristic cause for the most concern. The
largest impacts of the life cycle of the polystyrene cup are due to fossil resource depletion and excess
fossil carbon dioxide emissions. Reduction of fossil resource use in the production of polystyrene
would benefit the sustainability of polystyrene cups.
Although for other BTX product pathways and lifecycles the impacts are likely to differ somewhat, for
the bulk use of BTX (plastics) the impact profile will likely be similar to the one of the polystyrene
cup. Aside from efficiency improvements in the process, which can give significant reductions in fossil
resource use and in corresponding fossil CO2 emissions, replacing fossil-based plastics with biomassbased
plastics could decrease the impact of plastics production and use.
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2.3 Alternatives to fossil-based BTX
Biomass-based alternatives can be roughly divided into two groups: replacements for products and
replacements for precursors.
Biomass-based plastics that could replace styrene, terephthalic acid and nylon based plastics are
already commercially available (Jong, 2012). Poly-lactic acid (PLA), for example, is a well-known
example of a biomass based plastic (Cheng, 2011). PLA has two relatively large draw-backs, however;
it is based on starch crops and it has slightly different properties than the mass produced fossil-based
plastics it is replacing. While some of these properties, such as biodegradability, are seen as positive
traits for many (but not all) applications, other properties, such as low viscosity and brittleness, are a
negative for nearly all applications (although they also possess some positive traits). Starch crops are
also food crops, and production of PLA is therefore in competition with world food supplies. That it is
not a perfect replacement of fossil-based polymers is not so much and environmental concern as an
economic and technical-potential problem. The implementation rate will be lower, implying that the
environmental benefits will only be reaped later. But the physical properties of the alternative
(biomass-based) polymers may be so different from the fossil-based polymers, that they cannot be
applied to high performance materials. High-performance materials are increasingly important, as
they often contribute to a better environment in their own way, such as replacing steel parts in cars
and thereby reducing the weight and fuel use of the car (Eleni & Panagiotis, 2006).
Making biomass-based precursors thus has the advantage that the product is usable in the mature
market of fossil-based chemicals (Arbogast, 2012). With such “drop in” biomass-based chemicals, a
faster transition could be made in that case to a more sustainable society (Harmsen & Hackmann,
2012). An additional advantage is that the simpler the target compound, the more flexible the
technology is to the type of feedstock it gets. Instead of high quality starch crops, waste streams and
other relatively sustainable renewable feedstocks could be used, thereby taking away the
competition with food supplies. And since these drop-in chemicals have the same physical and
chemical properties as the fossil-based products they are replacing, there is no resulting loss in
quality or performance of the materials made with them.
Because of these two advantages of precursor production, the market readiness and the possibility
for using non-food biomass, research into producing BTX itself is making big strides.
16

3.0 Biomass-based BTX
In this chapter a short overview is given into how BTX can be produced from biomass, and what the
advantages and disadvantages of doing so could be.
3.1 Research towards biomass-based BTX
The production of BTX from biomass was first described in 1983 (Kotasthane, 1983), although the
formation of aromatic compounds is normal upon combustion of wood. The reason for this is that
about a third of woody biomass consists of lignin, large molecules made up of interconnected
aromatic rings (Bozell, 2008). If the lignin is broken down, the individual aromatic compounds can be
the product. Although this lignin fragmentation can take place at room temperature, research into
aromatics production focus on high temperature fragmentation, since this is more efficient.
Interestingly, pure lignin is not the best feedstock for BTX production (Cheng, 2011), it has a lower
yield than, for example, wood. Although the exact mechanics are not yet known, the formation of
aromatic rings through Diels-Alder reactions probably plays a role.
Although the first article on this subject appeared in 1983, it was not until the 2000’s that research in
this field intensified. Most research is directed towards catalytic pyrolysis, which is degradation of
the biomass under high temperature in the absence of oxygen. The catalyst is added to drive the
reaction towards specific products (Mihalick, 2012). Without a catalyst, the resulting pyrolysis oil is a
mixture of (oxygenated) hydrocarbons, which is used as fuel (Zhong, 2010).
Aside from pyrolysis, there are also several gasification reaction used to produce BTX, through
thermal degradation in the presence of some oxygen at higher temperature (Link, 2012). But because
of the higher temperature, the lignin is degraded to a larger extent, destroying the aromatic rings.
Some research is also directed at upgrading of pyrolysis oil and ethanol into BTX, although one can
imagine that the direct conversion of wood to aromatics without this step should theoretically be
more efficient (Valle, 2010; Inaba, 2005).
Reaction temperatures between 450 and 600 o C give the best BTX yields. Of the catalysts used, the H-
ZSM-5 doped with Gallium works best; although un-doped or doped with other elements also give
satisfactory BTX yields (Cheng, 2011).
Although research into and optimization of the process is on-going, some authors report quite high
yields already, like Mihalick et al. (2012) who achieve an energy efficiency for BTX production from
oak of 29% HHV.
The ratio of benzene, toluene and xylene resulting from the reaction varies strongly. The oak based
reaction by Mihalick et al. yields mostly para-xylene, whilst the reaction of Cheng et al. (2012) yields
mostly benzene. As mentioned in chapter 2, in the fossil-based BTX production process conversion of
the BTX ratio obtained to the one aimed for is standard practice. It will therefore be a balancing act
to find a biomass-based BTX process that optimizes the total yield with the efficiency of conversion
to the intended yield.
17

3.2 Advantages and disadvantage
The advantages of biomass-based BTX production are:
18
- The possibility of using non-food crops and waste biomass as a feedstock. Since agricultural
land is a limited resource, it should ideally be reserved for food production as food is an
essential human need. The use of waste streams is also beneficial, since this is making value
out of something that was less valuable before.
- The production of a precursor/”drop-in” chemical. “Drop-in” chemicals are chemicals of an
alternative source (in this case biomass) that are identical to the fossil-based chemicals, and
can thus be used in existing processes. This both shortens the transition to this alternative
source, and saves the cost of building new infrastructure and market.
- It has a relatively high value (see section 9.5)
- It has a relatively high chain efficiency compared to other biomass based processes (see
section 7.1)
The largest drawback to BTX production from biomass is that it requires biomass, which is only
available in a limited amount at a time, and there are more processes/uses that require it (Bergsma,
2010). Given this limitation, the advantages gained by replacing fossil-based processes with biomassbased
processes should be optimized by choosing the right processes to be replaced. This research
therefore compares environmental gains of the production of BTX from biomass to the gains from
alternative uses of biomass.

4 Alternative biomass use
In this chapter alternative uses of biomass are expanded upon.
4.1 Choice of biomass
As mentioned in the previous chapter, not all biomass feedstocks are considered sustainable. Part of
the reason is that many high yielding crops only grow well on agricultural land and thus compete
with food production (Bergsma, 2010). Another reason why a biomass feedstock could be considered
non-sustainable is that it requires too much energy and material to grow. Intensive crop production
requires fertilizers, pesticides and water, which all require energy to either produce or distribute.
This energy, when fossil-based, not only utilizes a non-renewable feedstock but also results in CO2
emissions.
So sustainable biomass is either a waste stream of food/crop production or can be cultivated in
relatively minimal conditions. Biomass that falls within this category is for example straw, corn
stover, waste wood or cultivated wood. Incidentally, these feedstocks are also a good feedstock for
BTX production. However, this lignocellulosic biomass can be used in other processes as well.
4.2 Uses of lignocellulosic biomass
4.2.1 Raw material
Woody biomass has been used as a raw material for thousands of years; timber to build, hemp for
rope, and more recently for making paper. Although the sustainability of these uses is important,
they are unlikely to show much change in the near future. Since this research is focused on a choice
for new uses of biomass, the raw material functions are not considered further.
4.2.2 Electricity and heat
Burning woody biomass for heat production is also an age old use. But this is mostly done on a
domestic scale in furnaces and stoves, not on an industrial scale. On an industrial scale, the co-firing
of power plants with biomass is a growing technology (Bergsma, 2010). Electricity production is one
of the main uses of fossil fuels, and accounts for a large share of anthropogenic CO2 emissions.
Although (partly) replacing fossil fuels in power plants with biomass could reduce these emissions, it
is a destructive use of biomass that may not get the most value out of the limited supply.
Additionally, electricity can also be generated by other renewable resources like wind, water and
solar energy. But, since electricity production is so predominant, it will be used in the comparison in
this research.
4.2.3 Fuel
Transport fuel, unlike electricity, is harder to make from alternative renewable resources (Ladanai &
Vinterbäck, 2009). Although hydrogen powered and electric vehicles are under development (or even
produced), biomass based fuels are still a sought after technology. Ethanol from sugar reed is used
on a very large scale in Brazil; many other countries have a targeted percentage they wish to achieve.
One of the problems with biomass-based fuels is that some compete with food supplies and others
have drastically low or even negative energy efficiencies, and are thus not very sustainable. The socalled
second generation fuels, however, are made from sustainable biomass and could have a
positive contribution to decreasing the impact of transportation. Ethanol can also be made from
woody biomass, although it is newer technology than the starch-crop based ethanol. Other pathways
19

are conversion to pyrolysis oil, or gasification to syngas with subsequent synthesis of Fischer-Tropsch
diesel.
4.2.4 Chemicals
Since chemistry is at a level where nearly any compound can be made from very basic starting
materials, virtually any chemical can be made from lignocellulosic biomass (Jong, 2012). Within
biomass-based chemicals, there are also certain obvious products from certain feedstocks (like
ethanol from corn), but in the future integrated bio-refineries could produce a large range of
chemicals (and heat and electricity) relatively independent of the feedstock. The more important
point is the efficiency with which compounds can be made of a feedstock. But even efficient
conversions should be placed in a context, like the sustainability of crop production and the degree
of environmental impact of the fossil compound it is replacing.
4.2.5 Other renewables
Figure 5 shows a diagram of the basic services that fossil carbon resources provide: heat and
materials, which in turn can then also be used for electricity and transport. On the right hand side,
various renewable resources and the services they provide are shown. Wind and water power can
only provide electricity and transport. Geothermal power can only provide heat. Solar power can
provide heat and electricity. Only biomass can provide materials; it is the only renewable source of
carbon.
Figure 5: Services from fossil and renewable sources
20

5 LCA and functional units
In this chapter the set-up for the life cycle analysis of biomass-based BTX is described. With this, the
functional units can be chosen as well as the production chains for arriving at the functional unit. The
next two chapters, six and seven, presents the inventories and results of the life cycle assessments.
5.1 Set-up of the life cycle analysis
The goal of this research is to identify the sustainability of biomass-based BTX production. Life cycle
analysis, LCA, is a tool that is used to determine the in- and outputs of a product over the chosen life
cycle (Finnveden, 2009). Life cycle does not necessarily mean from resource mining to the disposal of
the product, an LCA can also be performed from resource mining to the finished product, or just the
use phase of an item. The chosen system boundaries should be such that all the relevant stages are
taken into account. A proper definition of the functional unit, the product or process under study, is
therefore necessary.
As mentioned before (section 3.2), given the limited supply of sustainable biomass, a straightforward
comparison between biomass-based and fossil-based BTX would not give any information on
whether biomass-based BTX production is the optimal use of sustainable biomass. So aside from an
LCA of biomass-based BTX, other biomass-based processes will be considered as well. For each
biomass-based process, the fossil-based process will also be analysed, so the savings that a
replacement by biomass would give can be calculated. The biomass-based process that would give
the biggest savings would be the preferential one, from and environmental point of view.
Although LCA often considers a very large number of impacts, in this research, only fossil resource
use, CO2 emissions and land/biomass use are considered for simplicity sake. But since fossil resource
use and CO2 emissions are the most significant impacts of BTX (see section 2.1) the results are still
very relevant. Limiting the impact categories is done more often when larger numbers of processes
are considered (Cherubini 2009).
Indirect land use change, CO2 emissions associated with having to cut down forest to accommodate
increased use of cultivated land, is not considered here for simplicity reason. But since the biomass
considered is mostly wood, which has a small indirect land use change (ILUC) and nearly all processes
would have the same ILUC, this is less relevant (Sanchez, 2012; Cherubini, 2009).
5.2 Choice of processes for the functional units
BTX is part of a functional unit, but for the other uses of biomass, choices had to be made. As
mentioned in the previous chapter, the choice is limited to products/services that can be made from
lignocellulosic biomass, for reasons of sustainability and because this is the obvious choice for BTX
production.
From (lignocellulosic) biomass, one can either make energy (either electricity or heat), fuel or
materials. In this research, the choice was made to have at least one option from each of those
categories in the LCA, so that no value judgement would have to be made between them. It should
be noted though that materials are considered more valuable than fuel, and fuel more valuable than
energy. But in terms of demand, the fuel sector is the largest, and in terms of readiness level, energy
is the most common use of lignocellulosic biomass (Bergsma, 2010).
21

Within energy, electricity was chosen over heat since electricity is used for a wider range of services
and is generated centrally more often. For fuel, diesel was chosen, because the production of diesel
from wood (so-called Fischer-Tropsch diesel produced via gasification) is very promising and the
fossil-based counterpart is also common. Within BTX, the product ratio should be as is currently the
demand, i.e. 67:5:28 (Sweeney, 2008).
For other materials, research into the options from lignocellulosic biomass was performed. Research
into biomaterials from lignocellulose is relatively new, because the lignin component is relatively
inhomogeneous compared to cellulose or lipids in other biomass (Holladay, 2007). Research is mostly
focused still on analysing the product mixtures of treatment steps, rather than on producing single
market products. Products and processes can be divided into three groups: those that separate the
cellulose and use it as a feedstock, those that separate lignin and use it as a feedstock and those that
use lignocellulose as a feedstock (Ma, 2012). Products from cellulose range from PLA and ethanol to
furans. From lignin, polymer enhancers are made (keeping the molecule relatively intact) and all sorts
of aromatics and cyclical derivatives. From lignocellulose, separate products from the above could
also be isolated after, for example, pyrolysis, but another option is also to reduce all starting
materials to CO and H2 (syngas) and use that as a feedstock/starting point for more advanced
molecules.
The choice was made to have furandicarboxylic acid (FDCA) as the other material option from
lignocellulose. FDCA is a possible replacement of para-xylene in PET (making PEF as an end product),
and is currently being commercially developed for biomass-based plastics production (Eerhart, 2012).
FDCA is produced from the cellulose component of biomass, through enzymatic and mild acid
treatment. Using PEF instead of fossil-based PET could save up to 51% fossil fuel use and up to 54%
CO2 emissions (Eerhart, 2012).
Aside from FDCA, ethanol from lignocellulose was also considered. Ethanol is also at the base of a
range of other chemicals, among them polymers and thus fossil BTX replacements. However,
biomass based ethanol is currently mostly used as a fuel, and the fossil-route to ethanol goes via
ethylene. Ethylene is used more commonly as a materials precursor. Therefore both ethanol and
ethylene were modelled, so as to give a more complete picture.
5.3 Formulation of the functional unit
So the chosen processes are:
22
- Electricity production
- Diesel production
- Ethanol production
- Ethylene production
- BTX production
- FDCA production
The problem with FDCA production is that though it may be possible to synthesize fossil-based FDCA,
but that is probably a far more elaborate process than the biomass based route. At the very least,
there exists a fossil-based alternative: para-xylene based terephthalic acid (TA). Thus the choice was
made to make a separate comparison between biomass-based FDCA production and biomass-based

terephthalic acid production. Since they are stoichiometrically interchangeable for PET/PEF
production, the functional unit was 1 mole of FDCA or 1 mole of TA.
The other processes can be based both on biomass and on fossil resources. Although at first the
production volume in the functional unit was chosen arbitrarily (e.g. 1 kg ethanol or 1 MJ ethanol
from either fossil or biomass resources), a more correct comparison could be made using the
biomass processes as a basis for the functional unit. Since the question is what process would give
the largest (fossil resource and CO2 emission) savings for a given amount of biomass, the amount
each process could produce from 1 kg of biomass was chosen as the functional units. An earlier
example of such savings per unit of biomass LCA is research by Gustavsson et al. (1995). Table 1
shows the result of the output per kilogram of wood calculations.
Table 1: Biomass efficiency and products from 1 kg (higher heating value of 18.5 MJ/kg) of wood (based on own
calculations)
biomass efficiency MJ produced kg produced
electricity 0.206 3.814
diesel 0.341 6.309 0.143
ethanol 0.231 4.27 0.144
BTX 0.269 4.98 0.118
ethylene 0.253 4.68 0.098
5.4 System boundaries
With the functional units defined both in quantity and quality of products, the life cycle stages that
are to be taken into account were defined. Two separate LCA systems were designed, since the
comparison between biomass-based BTX and biomass-based FDCA had to be considered separately
from the other functional units because FDCA did not have a fossil-based route. As mentioned in the
previous paragraph, for this first system the functional unit was one mole of FDCA or one mole of TA
production. The unit of mole was chosen because this is a more fair comparison than a weight unit.
Having one plastic bottle as the functional unit would also have been a good comparison, but the
amount of PEF or PET needed for one bottle is subject to higher uncertainty than the amount of
FDCA or TA needed for one mole (which is exact). Only the production phase was considered because
the use and waste phase were assumed to be identical for FDCA and TA, since PEF and PET have
roughly similar properties. The first LCA system schematically represented in figure 6, and is the
subject of chapter 6.
Figure 6: LCA scheme FDCA versus TA
23

The other LCA system concerns the functional units described in table 1. Initially, only the production
phase was considered. But, since electricity produced from fossil fuels is based on the combustion of
those fuels and subsequent release of carbon dioxide, there was a bias towards replacing this
process. The processes that produce fuel or materials do not emit the contained fossil CO2 until the
use and waste phases. Therefore, for all processes, the use and waste phase were also considered.
The assumption was made, though, that the use and waste phases would be the same for biomass
and fossil sourced products. The only item considered different was the fossil CO2 contained and at
some point emitted from the fossil sourced products. So not considered were, for example, transport
and distribution of the products, energy needs for the use of them or the impact of the waste phase
processing.
The second LCA system is schematically represented in figure 7, and is the subject of chapter 7.
Figure 7: LCA scheme fossil versus biomass
5.5 Production chains from fossil fuel
Fossil to BTX: Since production of fossil-based BTX is performed by two relevant ways, reformate
(72%) and pyrolysis gas (24%), and global trade is prevalent, a weighted average of the average (so
not marginal) impacts and inputs/outputs of the two routes is used (Sweeney, 2008).
(Reforming) From crude oil, a mixture of hydrocarbons with a boiling point in the range of 70-190 o C
is obtained by fractioning. This mixture is hydro treated to remove impurities, which are removed by
distillation. The feed is then concentrated to limit it to C6-C8 hydrocarbons. After this it is fed to the
reformer, which works at high temperature and pressure and with a platinum-rhenium catalyst
(Sweeney, 2008). Presumably, a distillation process then separates the products.
(Pyrolysis) In this process, BTX is a by-product of the production of other hydrocarbons, mainly
ethylene (Sweeney, 2008).
24

In this research, data were taken from an average of several European plants.
Fossil to ethylene: Ethylene is produced by cracking the naphta (light hydrocarbon) fraction of crude
oil (Korschwitz, 2004).
Fossil to ethanol: Although large amounts of global ethanol are produced through biomass
fermentation when destined for consumption, industrial ethanol production proceeds through the
hydration of ethylene (catalytically in the vapour phase) (Logsdon, 2004).
Fossil to electricity: There are numerous ways of producing electricity from fossil sources. There is no
global trade in electricity but (at least in Europe) there is a regional trade. For the LCA calculations,
the average of the Dutch production mix was used.
Fossil to fuel: Since the transport fuel from biomass will be Fischer-Tropsch diesel, diesel will also be
used as the fossil-based fuel. Diesel is made of a blend of fractions from crude oil, and requires the
additions of additives to give optimal performance (Hochhauser, 2004).
5.6 Production chains from biomass
In all the routes below the starting point is wood chips, which also need to be produced themselves.
An appropriate type of woodchip was selected from the ecoinvent database.
Biomass to BTX: The most effective way of obtaining BTX from biomass is through catalysed
pyrolysis, as demonstrated by Mihalick et al. (2012) and Cheng et al. (2011). Production of BTX from
biomass is still at lab/pilot plant scale. It is likely that if it were produced on a large scale, the process
and process parameters are different, but for the sake of having a starting point the lab/pilot plant
parameters will be used. The woodchips are first torrefied (roasted) to remove moisture and then
ground, which requires less energy due to the torrefaction step (Phanphanich & Mani, 2011). After
these preparation steps, the ground wood is fed to the catalytic pyrolysis reactor in a continuous
feed. Along with the woodchips a catalyst and hot sand go through the reactor. The product gas is
removed in vapour form, the sand and char are collected at the end of the screw (Zhong, 2010). The
BTX is purified and separated through distillation, and the excess toluene and xylene are
hydrodealkylated into benzene, to yield the 67:5:28 ratio that is the current demand (Sweeney,
2008).
Biomass to ethanol: As mentioned above, producing ethanol from biomass is very common.
However, ethanol production from wood is less common, since the standard fermentation method
does not work with the majority of components in woody biomass without some processing steps
(Gnansounou and Dauriat, 2010). The general process of obtaining ethanol from wood contains the
following steps: pre-treatment in dilute acid, hydrolysis (which yields cellulose and glucose),
fermentation (sometimes in combination with the hydrolysis step) and then concentration of the
produced ethanol. Lignin is a solid waste product in the process, since only the cellulose and hemicellulose
components can be hydrolysed to sugars (Ko, 2012; Treasure, 2012).
Biomass to ethylene: Ethylene production from biomass is already performed commercially in Brazil
(Braskem 2012). The feedstock used in that process is sugarcane (via ethanol), in this research the
basis will be the ethanol produced from wood, which is then dehydrogenated to ethylene.
25

Biomass to electricity: Producing electricity from biomass can simply be achieved by burning the
biomass in a steam turbine power plant (Patzek & Pimentel, 2005).
Biomass to fuel: Although there is a large array of fuels possible using biomass as a feedstock, FTdiesel
is the most energy efficient from woody biomass (Patzek & Pimentel, 2005). FT-diesel is
produced in the Fischer-Tropsch process, where a mixture of CO and H2 is reacted exothermally to
produce hydrocarbons. Syngas can be obtained from dry biomass by gasification and subsequent
removal of contaminants (Langeveld, 2010).
Biomass to FDCA: Eerhart et al. (2012) have researched the process of producing FDCA from corn.
The corn is first processed into fructose, which is then converted to HMF, and subsequently
oxygenized to FDCA. Aside from this corn based process, a poplar based process that produces HMF
is also considered.
26

6 LCA of biomass-based FDCA and TA production
In this LCA, the production of biomass-based PEF and biomass-based PET is compared. PEF and PET
differ only in that PEF is made with the monomer furandicarboxylic acid (FDCA) and PET with the
monomer terephthalic acid (TA, or PTA when purified).
6.1 Inventory
Because of the relatively complex LCA model, only the land and fossil resource inputs and the CO2
outputs are considered, rather than a complete assessment of all the possible emissions and impacts
of life cycles. Additionally, although for most processes these data are available in the Ecoinvent
database that was used for them, for some of the biomass based processes only limited data is
available. Table 2 below gives a summary of the inventory. For a more detailed inventory, see
appendix B.
Table 2: Inventory FDCA and TA LCA
Fossil renewable
land
energy energy biomass use
Process unit (MJ) (MJ) (MJ (m 2 CO2
emissions
) (kg)
terephthalic acid from wood 1 mole 3,16 0,09 14,98 0,55 0,17
FDCA from corn 1 mole 2,31 0,00 ? 0,30 0,13
FDCA from poplar 1 mole 3,48 0,00 29,32 1,07 0,21
6.2 Method
For this LCA comparison the functional unit was producing 1 mol of FDCA or 1 mole of TA, and
comparing the in- and outputs of the processes (Finnveden, 2009). Mole is a unit that describes
amount of chemical substance. 1 mol was chosen rather than 1 kg, because FDCA has a lower mass
than TA, whilst on a stoichiometric basis equal amounts are needed to produce one mole of PEF/PET.
Using mole as a basis for comparison thus makes sense on a chemical level.
The uncertainty of the data was defined using the pedigree matrix for uncertainty, which gives
separate uncertainties for different factors, which are then combined to a single uncertainty factor.
These factors were then used to calculate higher and lower values for the calculations (Frischknecht
& Jungbluth, 2007).
The sensitivity analysis was performed by calculating what the effect on the end-results was of an
increase in certain inputs.
6.3 Results
Figure 8 shows the fossil resource use per mole for the different processes. As is evident from the
graph, FDCA from corn shows the lowest fossil resource needs, and FDCA from polar the highest.
However, within the uncertainty FDCA from poplar could also be the lowest, and FDCA from corn the
highest in fossil resource use. For the biomass-based TA process, the production of xylene only
accounts for slightly over 1/3 of the emissions and fossil resource use. The oxidation of xylene to
terephthalic acid has a far bigger impact, since it is an energy intensive process (see appendix B).
27

Fossil resource use in MJ
Figure 8: Fossil resource use in MJ per mole
Figure 9 shows the CO2 emissions per mole of the different processes, again showing corn based
FDCA to perform the best and poplar FDCA to perform the poorest. Again, within the uncertainty
margin, the order of performance could be entirely the reverse. As with the fossil resource use, the
oxidation of xylene accounts for more than half of the impact/emissions.
CO2 emissions
Figure 9: CO 2 emissions per mole of product
Figure 10 shows the land use per mole of the different processes, again showing FDCA from corn
performing the best and FDCA from poplar the worst. Here, the uncertainty is smaller, so even near
the extremes FDCA from poplar still has the most land use and FDCA from corn the least.
28
6
5
4
3
2
1
0
0,35
0,3
0,25
0,2
0,15
0,1
0,05
0
Teraphtallic
acid from
wood
Teraphtallic
acid from
wood
FDCA from
corn
FDCA from
corn
FDCA from
poplar
FDCA from
poplar

land use in m2
1,8
1,6
1,4
1,2
1
0,8
0,6
0,4
0,2
0
Teraphtallic
acid from
wood
FDCA from
corn
Figure 10: Land use per mole of product
FDCA from
poplar
The reason FDCA from poplar performs poorly is that the HMF yield from poplar is very low. The
process thus requires a lot of biomass input, with its associated energy requirements and CO2
emissions.
It is important to note, though, that the biomass-based BTX process could also use waste streams as
a feedstock. This would mean that the land use is virtually non-existent, which is a distinct
advantages over processes that require quite specific feedstocks, like the FDCA process.
The results of the sensitivity analysis are shown in appendix D. In summary the results are:
- The FDCA process, which uses only direct in- and output data for the whole process, is
entirely dependent on these data (as expected)
- For the CO2 emissions of TA production, the TA process (oxidation of xylene) is most
important
- For the land use of TA production, the amount of biomass needed for BTX production is most
important
- For the fossil resource use of TA production, again the TA process is the most important
- For the CO2 emissions of FDCA from poplar production, the emissions of the oxidation of
HMF and the emissions of extracting the HMF are the most important.
- For the land use of FDCA from poplar production, the amount of HMF obtainable from wood
is most important
- For the fossil resource use of FDCA from poplar production, the resource use of the oxidation
of HMF and the resource use of extracting the HMF are the most important.
So improvements in the TA process would be most beneficial for the sustainability of TA production,
and improvements in the oxidation of HMF and the extraction of HMF from wood would be most
beneficial for the sustainability of the FDCA from poplar process.
29

6.4 Inventory discussion
For TA from wood and FDCA from poplar, it was assumed that the higher heating value of the used
biomass is 18.5 MJ/kg, in practice there is variation in the HHV of woody biomass.
6.4.1 Terephthalic acid from wood
The discussion points for biomass-based BTX production also apply to this process.
A xylene isomerisation step is not included here because of the specific data on BTX yields used in
the inventory; the conditions used by Mihalick et al. yield para-xylene almost exclusively.
The whole production process from biomass pyrolysis to terephthalic acid production combined will
probably give more opportunity for heat management, reducing the amount of fossil resources
needed and CO2 emitted.
6.4.2 FDCA from corn
The energy needs and CO2 emissions associated with corn production and milling into glucose used in
the source are on the low side. Although part of this is due to the combustion of waste streams for
process energy, offsetting some of the fossil resource need and CO2 emissions, the data used in the
source article are lower compared to other data found in Ecoinvent for starch from corn in Germany.
CO2 emissions associated with indirect land use change (ILUC) were not taken into account here,
since the ILUC emissions were not given for the other feedstocks either. However, in the source
material (Eerhart et al, 2012) it was calculated that ILUC can add up to 0.7 kg of CO2 per kg of PEF
produced. This translates to 0.81 kg CO2 per kg of FDCA (the ILUC is associated with just FDCA
production, not the rest of the PEF production; per kg PEF 0.86 kg FDCA is needed). Per mole of
FDCA, the functional unit of the LCA, this doubles the value from 0.13 to 0.26 kg CO2 per kg CO2
produced, which is significantly higher than the CO2 emissions of biomass-based TA production.
Although the production of woody biomass for this TA production can also add some ILUC emissions,
these are generally lower than the corn ILUC emissions. So taking ILUC into account it is likely that
production of FDCA from corn would have higher CO2 emissions than TA from wood.
6.4.3 FDCA from poplar
The data used for the HMF yield from poplar were on a preliminary research paper (Yang, 2012), in
the future HMF yields from poplar can probably be optimized. However, the value used in the
calculations for the energy requirements of the production of HMF from poplar are possibly an order
of magnitude too low, since they were based on the mass of the product rather than the mass of the
input. Since part of the process is acid-hydrolysis of the biomass, the energy requirement is
significant.
30

7.0 Biomass versus fossil LCA
In this LCA, several the biomass-based and fossil-based processes of several functional units are
modelled. The goal was to compare the savings in fossil resource use and CO2 emissions that the
replacement with a biomass-based process could achieve, in order to assess which use of biomass
would be the most sustainable. The functional units under consideration are electricity, diesel,
ethanol, BTX and ethylene. The volume of each product to be produced in the functional unit is
dependent on the efficiency of biomass conversion of the process (see paragraph 5.3).
7.1 Inventory
Because of the relatively complex LCA model, only the land and fossil resource inputs and the CO2
outputs are considered, rather than a complete assessment of all the possible emissions and impacts
of life cycles. Additionally, although for most processes these data are available in the Ecoinvent
database that was used for them, for some of the biomass based processes only limited data is
available. Table 3 shows the inventory of the production phase used for the calculations. The source
of the data and assumptions behind them are further expanded upon in appendix B.
Table 3: inventory of the LCA
Product/process IN OUT Efficiency
value
unit
fossil
resources
renewable
(biomass)
land
CO2
emissions
Energy
product
MJ MJ MJ m 2 kg MJ
Energy
efficiency
Fossil electricity 1 MJ 2.13 0.13 1 0.46
Fossil diesel 1 kg 50.3 0.1 0.05 0.44 45.7 0.90
Fossil ethanol 1 kg 44.4 0.3 0.09 1.06 29.8 0.67
Fossil BTX (67:5:28) 1 kg 62.8 0.2 1.40 41.8 0.66
fossil ethylene 1 kg 60.7 1.10 48 0.79
Biomass
efficiency
Biomass electricity 1 MJ 0.50 0.04 4.85 0.17 0.04 1 0.19 0.21
Biomass FT-diesel 1 kg 6.30 134 4.77 0.38 45.7 0.33 0.34
Biomass ethanol 1 kg 6.33 106 3.78 0.39 29.8 0.26 0.28
Biomass BTX 1 kg 11.0 0 155.4 5.69 0.72 41.8 0.25 0.27
Biomass ethylene 1 kg 21.6 189 6.74 1.42 48 0.25 0.27
Table 4 shows the fossil CO2 emissions in the use and waste phase. As mentioned in chapter 5,
because the biomass-based and fossil-based products are assumed to be identical in how they are
used and disposed of, only the fossil emissions due to combustion of the product are relevant.
Diesel and ethanol, used as fuel, are combusted in their use phase, producing fossil CO2. Biomassbased
ethanol and FT-diesel only emit biogenic CO2 in the use phase. It is assumed that BTX and
ethylene are used to produce plastics, and that the use phase does not differ for biomass-based and
fossil based BTX and ethylene plastics. However, when they are incinerated in the waste phase, fossil
based BTX and ethylene plastics will result in fossil CO2 emissions.
31

Table 4: Use and waste phase CO 2 emissions in kg and electricity that can be generated in the waste phase in MJ. Both
are per kg of wood input. (based on own calculations)
MJ produced Use phase Waste phase Electricity
emissions (kg) emissions (kg) generated (MJ)
electricity 3.81 - -
diesel 6.31 0.452 -
ethanol 4.27 0.275 -
BTX 4.98 - 0.399 0.585
ethylene 4.68 - 0.370 0.479
Table 5 shows the value per MJ of the different products. This is different from the value of the
processes, because the BTX and ethylene processes in their lifetime also produce electricity during
waste incineration. The amount of electricity produced is based on the amount of product, which by
the waste phase is assumed to have a combustion energy of 20.5 MJ/kg (HHV of PET, which both
xylene and ethylene are part of) and the incinerator is assumed to have an energy efficiency of 24%
(calculation by KNN advies b.v.).
Table 5: value of the products per MJ in 2012 euros (calculated from ICIS (2012) and Agentschap NL (2012))
value
(euro/MJ)
electricity 0,019
diesel 0,017
ethanol 0,019
BTX 0,019
ethylene 0,021
7.2 Methods
In this LCA, the best use for biomass is determined by comparing the fossil resource and CO2
emissions savings that can be achieved by using 1 kg of wood (HHV= 18.5MJ/kg) different ways. Table
4 shows the biomass efficiency (HHV product/HHV wood), and how much is therefore produced per
process. The fossil resource needs and CO2 emissions associated with producing these amounts of
product via the biomass-based route are then subtracted from the fossil resource needs and CO2
emissions associated with producing the same amount from biomass.
For example, electricity can be produced from wood with 20.6% energy efficiency (higher heating
value), thus 1 kg of wood yields 3.81 MJ electricity. Producing 3.81 MJ electricity from biomass is
associated with 0.15 kg CO2 emissions, whilst producing 3.81 MJ from fossil resources is associated
with 0.5 kg CO2 emissions. So by spending 1 kg of wood on electricity production, 0.35 kg of CO2
emissions can be avoided.
The uncertainty of the data was defined using the pedigree matrix for uncertainty, which gives
separate uncertainties for different factors, which are then combined to a single uncertainty factor.
These factors were then used to calculate higher and lower values for the calculations (Frischknecht
and Jungbluth, 2007)
32

The sensitivity analysis was performed by calculating what the effect on the end-results was of an
increase in certain inputs.
7.3 Results
Unlike in the previous chapter, where the graphs represented emissions and land a fossil resource
use, the main results in this chapter are represented in savings achieved by replacing fossil processes
with biomass-based processes. So while in the previous chapter small numbers/bars were considered
good (since they represent smaller resource uses and emissions), in this chapter larger bars/numbers
are better since they represent larger savings.
Table 6 shows the fossil resources and CO2 emissions saved by producing each functional unit from
biomass instead of fossil resources.
Table 6: fossil and CO 2 savings resulting from producing the functional unit from biomass
MJ produced Fossil resources saved CO2 emissions saved
in MJ
in kg
electricity 3.81 6.22 0.351
diesel 6.31 6.31 0.461
ethanol 4.27 5.48 0.371
BTX 4.98 6.17 0.481
ethylene 4.68 5.17 0.364
Figure 10 shows the fossil resource savings resulting from replacing the fossil resource based
processes with biomass-based processes. As is evident from the graph, ethanol and ethylene show
the smallest savings, and from a fossil resource conserving point of view should be the last processes
to be replaced by biomass. Biomass-based FT-diesel results in the greatest saving, although
electricity, diesel and BTX all give virtually the same savings.
However, the error margins for all functional units except ethylene are large. This is mainly due to
uncertainty in the biomass-based processes, but the uncertainty of the fossil-based processes also
contributes, especially for BTX. BTX has a large positive error margin, and since the process is far
from optimized it is more likely to achieve greater savings than calculated here.
33

Fossil resource savings per kg woof input
in MJ
Figure 10: Fossil resource savings per kg of wood input
Figure 11 shows the CO2 emission savings resulting from replacing the fossil resource based
processes with biomass-based processes. Here, the biomass-based BTX gives the greatest savings,
with biomass-based FT-diesel close behind. Biomass-based electricity, ethanol and ethylene show
lower savings. So from a CO2 limiting point of view, BTX should be the first process to be replaced
with biomass.
The error margins are also large with these results, but since the differences between the savings
achieved is bigger, it is likely that the calculated order of largest savings will remain as it is. The
difference in ratios between the CO2 emission savings and the fossil resource savings is due to the
fact that fossil diesel and BTX production have a relatively high CO2 output per unit of product
compared to the fossil resource input. A reason for this could be a higher use of coal in the process.
CO2 saving per kg wood input
in kg
Figure 11: CO 2 savings per kg of wood input
34
12
10
8
6
4
2
0
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0

Figure 12 shows the value that can be generated from a kilogram of wood. For BTX and ethylene, this
includes value from generating electricity during waste incineration. The BTX process generates the
largest amount of value per kg of wood, but the ethylene and FT-diesel processes generate about the
same. Ethanol production from biomass generates the least value per kg of wood.
Figuur 12: value generated per process per kg of wood
The results of the sensitivity analysis are shown in appendix E. In summary they are:
- For all biomass-based processes, the amount of biomass needed to produce a given amount
of product is very important for the resulting savings. This is due to the fact that the biomass
efficiency determines the volume of the functional unit, and if this volume is larger the inputs
and emissions of the fossil-based routes in the system also increases, and those in-puts and
outputs are important for the result.
- For the fossil-based processes, the fossil-resource use of the electricity and ethylene routes
are relatively important, as are the CO2 emissions of the electricity, ethanol and ethylene
routes for the achieved savings.
- The individual process steps of the biomass-based BTX process have a small contribution.
So increasing the conversion efficiency of the biomass-based processes is very important for their
sustainability.
7.4 Inventory discussion
For all biomass-based processes, it was assumed that the higher heating value of the used biomass is
18.5 MJ/kg, in reality there is variation in the HHV of woody biomass.
7.4.1 Fossil-based electricity
The data used are based on average Dutch electricity production, even though marginal data are
formally more appropriate here, since this is choice based LCA. However, biomass-based electricity
would be base load electricity rather than peak load, the latter is used for marginal data.
Rather than data of the Dutch electricity production, average European electricity could have been
used, to widen the region on which the results are applicable. Indeed, most of the processes in the
inventory are based on European or Swiss data.
35

7.4.2 Biomass-based electricity
The used data are from a Swiss plant using softwood pellets, there is probably some variation if other
wood is used or a different type of plant. There could possibly be some improvement in efficiency as
the technology matures.
7.4.3 Fossil-based diesel
Since this is very mature technology, the data is assumed to have a high degree of certainty, although
there is probably also a very slight variation based on region and feedstock.
7.4.4 Biomass-based FT-diesel
As mentioned in the inventory, the Fischer-Tropsch step is modelled minimally as only an energy
conversion step. On the one hand, there are probably fossil resource needs and CO2 emissions
related to process steps and plant construction/catalyst production. On the other hand, the heat
generated during the process is not taken into account; this could lead to efficiency improvements of
the whole production chain.
Additionally, while the assumption is made here that Fischer-Tropsch diesel has the same higher
heating value as commercial petroleum diesel, in practice there are some differences (

processes, coal or other fossil fuels are also used to power processes, leading to a different CO2
emission factor.
The hydrodealkylation step produces methane, which could be used to provide process energy. For
the production of 1 kg of BTX, this could be 6 MJ, about 60% of the fossil energy requirement.
In this inventory the wood feedstock was chipped, then torrefied, then ground. It has not been
determined what the optimal feedstock is or whether torrefaction would negatively impact the BTX
yield. However, the sensitivity analysis shows that these processes are of little impact on the results,
so there is leeway for a different feedstock preparation process.
7.4.9 Fossil based ethylene
Since this is very mature technology, the data is assumed to have a high degree of certainty, although
there is probably also a very slight variation based on region and feedstock.
7.4.10 Biomass based ethylene
Although the lowest estimate of energy requirement needed for dehydration of ethanol was used, it
is still relatively high energy requirement compared to the fossil energy requirement of ethanol
production itself. But it is comparable to values found in literature for the dehydration of ethanol to
ethylene (Liptow & Tillman, 2009).
The dehydration of ethanol costs energy and the hydrogenation of ethylene releases energy. The
fossil based ethylene process, which cracks ethylene directly, has a lower process CO2 emissions than
the biomass-based ethylene process, that requires the ethanol dehydrogenation step. However,
since the lifetime CO2 emissions and fossil resource requirements are higher, the overall
environmental impact of fossil-based ethylene is higher than that of biomass-based ethylene.
37

8.0 Discussion LCA results
In this chapter the results of the two LCA’s are discussed, following which in chapter 9, the macroeffects
that could influence the outcome are presented.
8.1 Outcome of the LCA’s
The first LCA, which compared the production of terephthalic acid and furandicarboxylic acid from
biomass, showed that the TA route from biomass performed slightly worse on all accounts than the
FDCA route from corn, but better on all accounts than FDCA from poplar. Since TA production is a
major product of BTX, this is important for assessing the sustainability of biomass based BTX
production. However, since FDCA production requires a starch rich feedstock, which is usually less
sustainable than wood or waste streams, TA production is probably more favourable on a big scale.
The oxidation of xylene to terephthalic acid has the largest impact, bigger than all the steps of
biomass-based xylene production, and research into lowering this impact is therefore also an
important step towards sustainability.
The second LCA, which compared the fossil resource use and CO2 emission savings of replacing
several fossil-based processes with biomass-based processes, was favourable for biomass-based BTX
on all accounts. However, biomass-based diesel performed about equally well, and the error margins
were large enough and the savings of each route close enough together such that the calculations
may perhaps not be properly reflecting the actual situation.
So overall the production of biomass-based BTX is relatively sustainable, compared to other uses of
land/biomass. But since the uncertainty margins are rather large and some other uses of the biomass
uses perform (slightly) better than BTX, an analysis of which direction of the margins will go most
likely is necessary.
8.2 Correlation in the margins
Although the margins are large, they are correlated to some extent. First of all, between electricity
and biomass-based BTX production are directly related, since biomass-based BTX production has an
electricity input. So if electricity production were to become more sustainable, the savings that
biomass-based electricity would yield are smaller, whilst the biomass-based BTX production would
give larger savings compared to fossil-based BTX production. It is safe to assume, though, that most
processes in the LCA even the fossil-based processes use some to a significant amount of electricity.
There is also probably correlation between the yields of products from biomass, with all of the
biomass-based processes having some potential for improvement. However, for the newer
technologies (BTX, ethanol/ethylene and FT-diesel) this potential is probably higher than for
electricity production.
Finally, there is correlation due to the fact that the uncertainty margins were determined by the
author using the Pedigree matrix. While this method gives a good backbone for determining
uncertainty, it is still subject to some judgement, and therefore there is a correlation due to the
harshness of this judgement.
8.3 Electricity differences
Among the fossil based processes, electricity production is most likely to change or be an inaccurate
representation. Since electricity production originate from so many sources, it differs greatly in
39

emissions and resource needs per country (Dones, 2004). Whilst in some European countries there
are a lot of inefficient coal fired power plants, in others electricity production is almost entirely based
on renewable resources. Therefore the choice of region in the LCA is quite important, especially since
this is also an important factor in the outcome of the second LCA. There is also a trend towards
sustainability in electricity production in Europe, as wind and solar energy are becoming more
popular with the consumer (Kitzing, 2012). So whilst at the moment electricity production in some
parts of Europe may be less sustainable than the current Dutch electricity production, in the long
term electricity production it is likely to be more sustainable in general, making the substitution with
biomass-based electricity less favourable.
However, the biomass-based BTX process would become more favourable if electricity were more
sustainable, since in this research the electricity need of the BTX process was met by the fossil-based
electricity. Since the fossil-based electricity actually reflects the Dutch productivity mix, a change in
its in- and outputs would correspond to a change in the in- and outputs of the biomass-based BTX
process.
40

9.0 Macro scale effects
In this chapter, the various macro scale effects are assessed, as well as their influence on the
outcome of the LCA’s is.
9.1 Using waste streams as feedstock
This paragraph deals with the possibility of using waste streams rather than virgin material as a
feedstock.
9.1.1 Advantages of using waste streams
The advantages of using waste streams as a feedstocks are two-fold: it saves the resources needed
for producing virgin material, and it generates value from an otherwise invaluable stream (Campbell
& Block, 2010).
For biomass-based processes, this means that the land requirement is negligible, which lowers
competition with food-crop production. Aside from land, the water, energy and materials/fertilizer
needed for production are also avoided. Usually, the processing of waste streams into feedstock also
requires some resources, but for plenty of waste streams this resource input is smaller than the
resources needed to produce virgin feedstocks. So using waste streams may make processes more
sustainable.
The generation of value from waste streams is not so much an environmental advantage as it is an
economic advantage. Although biomass waste is usually already used in some capacity, it is mostly in
low value products. New technologies such as BTX production could increase the value gained, and a
higher value also gives the opportunity to use harder to process waste streams that would otherwise
be too expensive to use. But since waste streams are low in value and sometimes a burden to
dispose of, there is a push-effect from the waste producer to engage in new technology. This could
be an incentive to introduce biomass-based processes faster, resulting in environmental benefits,
provided the biomass-based route is more sustainable than the alternative fossil-based route.
9.1.2 Processes with feedstock flexibility
Not all biomass-based processes are flexible in the type of feedstock the can use. Processes that use
certain inherent structures in the biomass, such as sugars or oils, need the feedstock to be high
enough in those structures in order to be profitable (Campbell & Block, 2010) The processes
considered in this research that could use waste streams are the biomass-based electricity, FT-diesel
and BTX/TA-processes. The electricity process can use any dried biomass, since it is combusted and
only the heat of that process is used to generate electricity, the structure of the biomass is
unimportant. The FT-diesel process uses gasification to first reduce the biomass to CO and H2 (and
other gasses). Whilst there is some variation in the quantity and ratio of the product gasses
depending on the structure of the feedstock, the process is relatively flexible. The BTX process is also
relatively flexible, even though the lignin content of the feedstock may be important to the yield.
However, biomass waste streams tend to be high in lignin content, since this is the biomass
component that is least useful for other processes such as food and oils.
The ethanol/ethylene and FDCA processes are less flexible to the feedstock. These processes are
heavily dependent on the sugar/cellulose content of the feedstock. For the FDCA process, this is
because the final product is derived from a sugar molecule. For the ethanol/ethylene process, the
ethanol is produced by fermentation of sugar. As mentioned before, waste streams tend to be high
41

in lignin and are usually low in sugar content, making them unsuitable for such processes.
Additionally, because these processes use bacteria, enzymes and yeasts, the feedstock has to be such
that it does not kill or deactivate the organisms and enzymes.
It should be noted, that the fossil based processes considered in this report are currently not adapted
to waste streams, except for electricity production. The latter will be explored further on in this
chapter.
So the FT-diesel, electricity and BTX/TA process have the potential to become more sustainable
through the use of waste streams, whilst the ethanol/ethylene process and FDCA production are
limited to high starch-content feedstocks.
9.2 Future trends in the petroleum market
In this paragraph, the future trends in the petroleum market and their effect on the results of this
report are explored. This is only a short overview; an upcoming report by KNN advies b.v. will look
further into the economic outlook of BTX on the market.
With fossil resources declining, prices of petroleum products increase, although not always linearly
(Cherubini, 2010). For BTX production, the price-trend is complicated by the fact that toluene and
xylene can also be mixed with transport fuel, which occurs more when fuel prices are high (or indeed
the demand for BTX is low) (PPE, 2012). But in general, it can be said that increases in the price of
fossil resource will be an incentive to use biomass-based processes. Either through a direct increase
in the price of the product, or because of an indirect price change because of a lowered demand in
the process that the product is a by-stream of.
Aside from this economic change, there can also be a change in the environmental impact of the
fossil-based resources. Some products could be made from coal rather than oil. Since coal has a
higher carbon content than the other fossil resources, the carbon emissions from those processes
(over their lifetime) will be higher than for oil and gas based processes (Brandt & Farrel, 2007). This
effect is enhanced by the fact that coal has to be mined, which is more damaging to the environment
(and humans) than extracting oil and gas from the land. This means that the savings of using a
biomass-based process would be even greater. Coal is already used to produce electricity and BTX,
although production of diesel and ethylene from coal is also technically possible.
Another transition within the petroleum industry is the (partial) transition to shale gas (ICIS, 2012).
Shale gas is natural gas trapped in shale, a mud-type layer. It is expected that shale gas use will
rapidly increase in the coming decades, since conventional natural gas resources are depleting.
Whilst some products are expected to become cheaper, such as electricity and ethylene (and thus
also ethanol), the prices of BTX and other refinery products are not likely to become lower. This is
because part of the crackers that produce BTX are expected to shut down with the rise of shale gas
(ICIS, 2012).
So future trends in fossil resources may increase interest in all biomass-based processes. But BTX is
affected both by the transition to coal and the transition to shale gas, while ethanol/ethylene is
expected to undergo the least change.
42

9.3 Renewable alternatives
As mentioned in chapter 2, for some of the fossil-based processes/products there is a variety of
renewable alternatives (McKinney, 2007). Figure 13 shows, once again, a schematic overview of the
fossil-based products and their renewable alternatives.
Figure 13: services from biomass and fossil resources
In this research, six products were considered: electricity, diesel, ethanol, ethylene, FDCA and BTX. If
diesel and ethanol are considered purely as transport, than electricity, diesel and ethanol also have
other renewable options. Ethylene, FDCA and BTX, being materials, need either fossil or biomass
feedstocks to provide the carbon sequestered in them.
With only a limited amount of renewable biomass available, it makes sense to utilize it for products
that have no renewable alternatives. The amount of solar energy received on earth is theoretically
abundant to provide all the energy humans use. In practice, there are logistic, economic, and cultural
restraints to switching entirely to solar energy. But the long term plan should be to focus biomass
resources on materials use as long as this is not less sustainable than using it for other processes. In
this research, it was concluded that using it for materials is a relatively good choice, although the
processes could benefit from improvement. The next question is whether the renewable alternatives
for the processes that are not biomass-based are sustainable. The overall answer is yes (McKinney,
2007).
9.4 Corn as a feedstock
As mentioned before, using corn as a feedstock for non-food processes is a threat to global food
resources (Pimentel, 2003). High yield food crops, such as corn, require fertile soil. Whilst with
irrigation and fertilizer and other auxiliaries the amount of agricultural land can be expanded
somewhat, new agricultural land is largely made by cutting down (rain) forest. Since this may lead to
an increase greenhouse gas emissions and a decrease in biodiversity it is considered unsustainable.
Although globally there is enough food per capita, for a variety of reasons, in practice there still a
substantial incidence of famine (McKinney, 2007). This is only expected to increase in the coming
decades due to population increases and droughts, despite the also anticipated increases in some
agricultural yields. It would therefore be unethical to strive to increase substantially the share of nonfood
uses of agricultural land.
43

The impact of this on the production of FDCA from corn is that while on a small scale it is relatively
sustainable; on a large scale it is undesirable due to food shortages and environmental reasons.
9.5 Cascading and recycling
Figure 14 shows the value pyramid for utilities used in society. At the top are pharmaceuticals,
followed by specialty chemicals, followed by food, followed by materials (such as clothing, timber,
plastic bags) followed by fuel, with electricity and heat at the bottom (Bergsma, 2010).
Figure 14: value pyramid utilities
While the value is highest at the top, the volume of production is largest at the bottom. Producing
medicines is relatively difficult, producing heat is easy. In paragraph 9.3 it was mentioned that
manufacturing products from the upper part of the pyramid is a good use of biomass since it is the
only renewable source of carbon. Making products from the top of the pyramid is also useful
because of “cascading”, in which biomass (or another resource) is first used to make products for
which high quality or a specific feedstock is needed, and then using waste streams of that process to
generate products lower in the pyramid.
For example, although this is quite a specifically excellent example, from a taxus tree one could first
extract the specific structures in the plant that make cancer medication, then use the rest of the tree
in a pyrolysis process to produce chemicals and plastics (Yazdani, 2005). When those plastics are
collected, they could then be used in building materials such as for insolation purposes. If this is then
disposed of, the waste could be incinerated to generate electricity and heat. With such a process,
almost the entire value pyramid is catered to. Whilst if electricity was directly produced, other
resources would have to be employed to produce other parts of the pyramid.
Aside from cascading, recycling is also a way to get more out of a resource (McKinney, 2007).
Recycling of chemicals and materials is increasingly used as a way to limit resource use and
environmental burdens. Although recycling requires a well-functioning logistics network to separate
and reprocess materials and chemicals, it is often worth the effort. And even though, for example,
recycling plastics is a difficult process because not all plastics can easily be reprocessed, there is still
more potential than for recycling fuel, heat and electricity. Once the latter three are used, they
cannot be recovered since they are simply spent.
44
pharmaceuticals
chemicals
food
materials
fuel
electricity
heat

So producing ethylene, FDCA and BTX/TA from biomass has a distinct advantage over producing fuel
and electricity, since the former can be part of a cascading or recycling chain, making the most of the
resources.
9.6 Scale potential
In this paragraph the potential of the different biomass-based processes is calculated, based on the
amount of available sustainable biomass in 2020-2030. Whether or not all of this biomass is suitable
as a feedstock is at first not considered, the assessment is only based on the conversion efficiency.
The sustainable biomass potential is a point of discussion, since it is partly based on assumptions and
not all researches take the same constraints into account. Assumptions have to be made on how
yield increases will develop and how much land will be used. Constraints on how much land is
needed for food crop production are also not universally accepted. Therefore, a high and a low
estimate are used. The conservative estimate for the global sustainable biomass potential in 2020-
2030 is 33 EJ, the optimistic 100 EJ (Bergsma, 2010).
Table 7 shows the resulting possible amounts of product that can be produced from this biomass.
Obviously, not all the renewable biomass resources will ever be used for a single process, but these
calculations do give an estimate of scale. Aside from the production potential, the current use of the
products is given, which for most products is currently based on fossil resources (except for ethanol).
Table 7: production potential based on available sustainable biomass
Product conversion low estimate high estimate current use
efficiency (EJ)
(EJ)
(EJ)
electricity 20.6% 6.8 20.6 70.9
diesel 34.1% 11.3 34.1 25.2
ethanol 23.1% 7.6 23.1 2.4
ethylene 25.3% 8.4 25.3 5.2
BTX 26.9% 8.9 26.9 4.6
As is evident from the table, the world demand for ethanol, ethylene and BTX could theoretically be
made met by biomass, although it would require a significant amount when the lower estimate is
correct. Diesel demand could be met, if the renewable biomass volume is higher than the average
estimated potential. Electricity demand is too great to be met by biomass, with even the high
estimate case being less than a third of the demand.
What direction the ratio of biomass use will go cannot directly be predicted by these figures.
However, looking at a combination of the value and the demand, an estimate is made here
nonetheless.
Although electricity is a low value use of biomass, see figure 14, the demand is so high that a large
share of biomass will probably go to electricity production, especially since biomass can be used as a
back-up or co-firing feedstock for coal and waste incineration plants.
Ethanol is also a relatively low value use of biomass, but is currently one of the larger shares, because
it is relatively straightforward to produce, and the changes required in the transport system to
accommodate ethanol are relatively small (Campbell & Block, 2010). But since it has a relatively
45

lower value and its sustainability is under discussion, it is not expected that ethanol production from
biomass will grow a lot.
FT-diesel from biomass, on the other hand, is expected to grow quite a lot, since research shows
that, when made from sustainable biomass, it is one of the most sustainable fuels available.(Swain,
2011) It is also high in value and demand, although there would probably be some logistic barriers to
be overcome.
Ethylene and BTX are both relatively high value uses of biomass with a sizeable demand, they could
therefore potentially form an important part of biomass use, especially when fossil resources
dwindle. But since their market are relatively small in size (compared to fuel and electricity), it is
unlikely that they will form a major part of biomass use, unless fossil alternatives would be nonexistent.
For smaller scale production BTX has an advantage over ethylene production, because BTX
(liquids) are easier to store and handle than ethylene (gas).
Although it is hard to predict how the biomass-based market will develop, it can be concluded that in
a cautiously optimistic scenario, BTX, ethylene and ethanol could all be made from sustainable
biomass, but electricity and electricity will probably become the major uses.
9.7 Conclusion
Table 8 shows a summary of this chapter, for each biomass-based process. The second column shows
whether or not waste streams can be used for the process; the third column shows whether the
trends in the petroleum market are beneficial for the future of the biomass-based process or not; the
fourth column shows whether or not there are renewable alternatives; the fifth column shows
whether the process needs a food crop as a feedstock; the sixth column shows whether the process
has cascading or recycling potential; the seventh column shows whether a significant amount of the
global demand could be met in the future using sustainable biomass resources.
Table 8: Summary of this chapter
46
can use
waste
steams
petroleum
market
trends
renewable
alternatives
corn/food
crop
feedstock
cascading/
recycling
potential
demand
electricity yes beneficial yes no no high
diesel yes beneficial indirect no no moderate
ethanol no neutral indirect sometimes no low
ethylene no neutral no sometimes yes low
BTX/TA yes very no no yes low
beneficial
FDCA no very
beneficial
no yes yes -
In order to show this more clearly, the entries in the previous table were converted to scores, with a
poor quality (such as the inability to use waste streams) being scored a -1, a good quality (such as the
ability to be recycled) a +1, and neutral or ambiguous ones scored a 0. The results are shown in table
9, along with the total of the score. The demand is considered neutral, “0”, for all, since it is not
considered a positive or negative macro effect.

Table 9: Numerical summary of this chapter, the demand column is not used in the total
can use
waste
steams
petroleum
market
trends
renewable
alternatives
corn/food
crop
feedstock
cascading/
recycling
potential
demand TOTAL
electricity 1 1 -1 1 -1 0 1
diesel 1 1 0 1 -1 0 2
ethanol -1 0 0 0 -1 0 -2
ethylene -1 0 1 0 1 0 1
BTX/TA 1 1 1 1 1 0 5
FDCA -1 1 1 -1 1 0 1
This is of course a simplification of the conclusions drawn above, and not all the different qualities
should count the same. But we can conclude that the production of BTX from biomass has many
attractive qualities, whilst the production of ethanol is not that attractive. Diesel production scores
second best, whilst electricity, ethylene and FDCA score somewhere in-between. There are probably
more large scale trends and effects that affect these processes, in this analysis, biomass-based BTX
production seems very promising in this analysis.
47

10 Discussion
The first paragraph discusses the research in general; the second compares the results of this
research with the results by other authors.
10.1 General discussion
In this general discussion the overall approach to the research is discussed, as well as a summarized
discussion of the LCA’s and macro effects. The aim of this research was to assess whether or not
production of biomass-based BTX is sustainable. The research questions (section 1.2) were all
answered to some extent.
In chapter two, the choice was made to model the impact of fossil based BTX by modelling a
polystyrene cup, since polystyrene is one of the major products made with BTX. But since
polystyrene is only one of a very large range of possible end-products, this is not entirely
representative of the whole spectrum. Choosing a pharmaceutical or longer life material or even a
fuel derived from BTX, the impacts would probably be different. However, since there was such a
clear indication that fossil resource use and greenhouse gas emissions were the most important
impacts that the author deems it likely that this will be the trend for most BTX products.
Furthermore, while polymers are not the only product from BTX, they are the main product and the
target product for biomass-based BTX and are therefore the most obvious choice to study. Therefore,
the choice of modelling a polystyrene cup as a representative of BTX products was reasonable.
For the discussion into what alternative uses of woody biomass there are, the choice was made to
limit the categories and products under consideration, for simplicity sake. There are likely to be other
important uses of woody biomass, but the products under consideration all had high volume fossil
counterparts (except for FDCA), and were therefore relevant to study. Secondly, products within the
same categories and with similar biomass conversion efficiencies probably give similar results, since
in this research the results are even relatively close between different categories.
For the choice of which biomass-based routes were included in the LCA’s, choices were partly based
on what information was available. Since the Ecoinvent database is convenient and relatively reliable
and consistent, where possible it was employed, although this might mean that in some cases the
data were more specific to a single plant rather than the general trend. Additionally, other choices
were also slightly arbitrary, choosing diesel over gasoline and the choice of Dutch electricity
production over European electricity production.
In the inventory, a higher heating value of 18.5 MJ/kg was used for all woody biomass, whilst in
practice there is some variation depending on the type of wood and whether or not it has been
dried. Although this would alter the results somewhat, overall it would create little relative changes
between the savings of the biomass-based process, since they would all change by about the same
amount.
In this research, the only impacts considered were fossil resource use and CO2 emissions, and for the
FDCA/TA LCA, land. The other impacts, such as acidification potential, toxicity or indeed non-CO2
greenhouse gas emissions were not taken into account, to keep the LCA’s simple. Including the other
impacts could very well change the relative performances of the biomass-based processes.
49

The data used in this research were average rather than marginal data; this was mainly done because
average data are more widely available than marginal data. But because the aim of the research was
on the impact of large scale application of the processes under consideration rather than of a single
plant, using average data was the appropriate choice either way.
The error margins of the LCA’s were rather large, which could be due to being too strict in
determining uncertainty. Using a Monte Carlo to determine the statistically relevant uncertainty
would probably have narrowed the margins.
The general approach to the question of the sustainability of biomass-based BTX is considered
appropriate. As pointed out above, there is room to improve the details and data sourcing.
10.2 Comparison with other research
Eerhart et al. (2012) show in their LCA of biobased PEF that it is more sustainable than fossil-based
PET and more sustainable than biobased PLA, PHA and PE, although the latter two are also more
sustainable than petrochemical alternatives.
Tijmensen et al. (2002) explore the options for producing FT liquids to replace various fuels, showing
that they are already cost effective, which would be very beneficial for their breakthrough into the
market, thus competing with BTX from biomass.
An LCA of platform chemicals from lignocellulosic biomass in a biorefinery showed that greenhouse
gas emission reductions of 37-48% could be achieved and a fossil fuel use reduction of up to 80%.
Compared to this research, the GHG reductions are on the low side, but the fossil resource use
reductions are comparable. (Hipolito 2011)
Willems (2009) sheds a light on the obstacles facing biomass-based chemicals, the largest being
transport difficulties and the enormous gap between lab scale and commercial production. The latter
problem is less of an issue for biomass-based platform chemicals such as BTX, since they are drop-in
chemicals. But the transport issue is important, since for biomass-based BTX the feedstock is also
spread out, and conversion plants are most likely more profitable when they are centralised.
Therefore there is a need for further research into the effects of transport on the economic and
environmental impacts of biomass-based BTX production.
Ragauskas et al. (2006) give a strong argument for the biorefinery: an integrated plant that makes
the most out of sustainable biomass to produce the services that humans need. This is in line with
the argument made in this paper that cascading and recycling are important, as are the use of waste
streams.
A 2006 report by CE (Croezen, 2006) looked at the current options for replacing petrochemical
processes with bio-based processes and concluded that the price and relative obscurity of biomassbased
chemicals are a problem, and that for some processes the land use and process energy are
rather high. It also comments on the unequal playing field created by the stimulus of green electricity
and fuels, which makes it hard for biochemical to break through onto the market. While these
conclusions complement or agree with the results of this research, it should be noted that in the
report most processes relied on non-sustainable biomass.
50

A DOE research (Holladay, 2007) on opportunities for lignin usage concluded that while lignin has a
potential high impact, technologically speaking only power, fuel and syngas are short-term
opportunities, with aromatics production a long term goal. While this research agrees that lignin has
a high impact, it does not agree that aromatics production from lignin is a long term goal, since the
BTX yield from lignocellulosic biomass is already high enough to be commercially viable. But that
could be due to the five years between the researches, a period during which the field has
progressed quite significantly. It should be mentioned that pure lignin is not the ideal feedstock for
the biomass-based BTX process, although in a biorefinery framework the lignin is a waste stream
which is suitable for little other products.
A 2010 report by CE (Bergsma, 2010) concludes, like this research, that for the Netherlands
producing chemicals from biomass is an excellent use of biomass, and that agricultural crops should
not be used for fuel production. Biomass-based electricity is also considered good use even in the
long term, but this is probably in light of the decision to build more coal fired power plants in the
Netherlands.
So overall this research is in agreement with other reports on the subject, but because there are so
many options for biomass use and parameters to consider, there is some differentiation.
51

11 Conclusion
The question addressed in this research was whether the production of BTX from biomass was a
sustainable use of the resource. The environmental impacts of fossil-based BTX were examined, from
which it was concluded that the fossil resource depletion and greenhouse gas emissions were the
major impacts. Biomass-based BTX has the potential to become a large use of woody biomass. And
though it is a new process, advances made in the field are such that yields are comparable to other
biomass-based routes. Five other uses of biomass (ethanol, ethylene, FT-diesel, electricity and FDCA)
were also examined, chosen to represent the different kind of products from biomass. The life cycle
assessment of the fossil resource inputs and CO2 outputs of all these systems revealed that per
kilogram of wood input, biomass-based BTX production gave the biggest improvement compared to
the fossil-based route. Biomass-based diesel also performed well. Comparing FDCA with biomassbased
TA showed that FDCA from corn had lower fossil resource input and CO2 output, but wood
based FDCA performed worse. Since corn is however also a food crop, it is not an entirely sustainable
feedstock. Other macro effects that were not included in the LCA were the possibility of using waste
streams, renewable alternatives, the possibility of cascading and recycling, the trends in the
petroleum market and the scale potential. Aside from the scale potential, which is neutral either
way, the other four macro effects gave a positive outlook to the production of biomass-BTX, while
some of the other products under consideration were negatively or not as positively affected.
So overall, from this research, it can be concluded that:
- Biomass-based BTX production is more sustainable than fossil-based BTX production
- Compared to other uses of lignocellulosic biomass, BTX production performs equally or even
better. However, within the LCA system the differences were rather small and the error
margins large, which means that the individual parameters are relevant.
- In the study of the macro effects, it was shown that trends in the petrochemical industry, the
possibility to use waste streams and other factors would benefit biomass-based BTX
production more than the other biomass-based products.
Further research should focus on performing an LCA on other impact categories as well, since this
may clarify the differences between the processes. Furthermore, the effect of logistic difficulties such
as transport from the biomass production site to industrial sites should be researched, as well as the
effect of the specific technologies and feedstocks used for the biomass-based BTX process. Practical
research into streamlining the production process so that fuel use and emissions could be further
minimized and waste stream usage optimized would also benefit biomass-based BTX production,
although the outlook is very good already.
53

12 References
Abuadala, A., & Dincer, I. (2012). A review on biomass-based hydrogen production and potential
applications. International Journal of Energy Research, 36(4), 415–455. doi:10.1002/er.1939
Agentschap NL (2012). Kosten en Baten. http://www.windenergie.nl/onderwerpen/financien/kostenen-baten
Arbogast, S., Bellman, D., Paynter, J. D., & Wykowski, J. (2012). Advanced bio-fuels from pyrolysis oil:
The impact of economies of scale and use of existing logistic and processing capabilities. Fuel
Processing Technology, 104, 121–127. doi:10.1016/j.fuproc.2012.04.036
Benner, J., Lieshout, M. van, & Croezen, H. (2012, January). Identifying breakthrough techonologies
for the production of basic chemicals. CE Delft.
Bergsma, G. C., Kampman, B. E., & Croezen, H. J. (2010, April). Goed Gebruik van Biomassa. CE Delft.
Bessou, C., Ferchaud, F., Gabrielle, B., & Mary, B. (2011). Biofuels, greenhouse gases and climate
change. A review. Agronomy for Sustainable Development, 31(1), 1–79. doi:10.1051/agro/2009039
Blaauw, R., Haveren, J. van, Schott, E. L., & Bos, H. L. (2008, March). Biomass for the Dutch Chemical
Industry. Agrotechnology and Food Sciences Groep.
Bozell, J. J. (2008). Feedstocks for the Future - Biorefinery Production of Chemicals from Renewable
Carbon. CLEAN - Soil, Air, Water, 36(8), 641–647. doi:10.1002/clen.200800100
Brandt, A. R., & Farrell, A. E. (2007). Scraping the bottom of the barrel: greenhouse gas emission
consequences of a transition to low-quality and synthetic petroleum resources. Climatic Change,
84(3-4), 241–263. doi:10.1007/s10584-007-9275-y
Bridgewater, A. V., & Peacocke, G. V. C. (2000). Fast Pyrolysis processes for biomass. Renewable and
Sustainable Energy Reviews, (4), 1–73.
Brundtland Comission (1987).
http://yosemite.epa.gov/r10/oi.nsf/8bb15fe43a5fb81788256b58005ff079/398761d6c3c7184988256
fc40078499b!OpenDocument
Campbell, J. E., & Block, E. (2010). Land-Use and Alternative Bioenergy Pathways for Waste Biomass.
Environmental Science & Technology, 44(22), 8665–8669. doi:10.1021/es100681g
Capello, C., Wernet, G., Sutter, J., Hellweg, S., & Hungerbühler, K. (2009). A comprehensive
environmental assessment of petrochemical solvent production. The International Journal of Life
Cycle Assessment, 14(5), 467–479. doi:10.1007/s11367-009-0094-4
Chareonlimkun, A., Champreda, V., Shotipruk, A., & Laosiripojana, N. (2010). Reactions of C5 and C6sugars,
cellulose, and lignocellulose under hot compressed water (HCW) in the presence of
heterogeneous acid catalysts. Fuel, 89(10), 2873–2880. doi:10.1016/j.fuel.2010.03.015
Cheng, Y.-T., Jae, J., Shi, J., Fan, W., & Huber, G. W. (2012a). Production of Renewable Aromatic
Compounds by Catalytic Fast Pyrolysis of Lignocellulosic Biomass with Bifunctional Ga/ZSM-5
Catalysts. Angewandte Chemie International Edition, 51(6), 1387–1390. doi:10.1002/anie.201107390
55

Cheng, Y.-T., Jae, J., Shi, J., Fan, W., & Huber, G. W. (2012b). Production of Renewable Aromatic
Compounds by Catalytic Fast Pyrolysis of Lignocellulosic Biomass with Bifunctional Ga/ZSM-5
Catalysts. Angewandte Chemie International Edition, 51(6), 1387–1390. doi:10.1002/anie.201107390
Cherubini, F., Bird, N. D., Cowie, A., Jungmeier, G., Schlamadinger, B., & Woess-Gallasch, S. (2009).
Energy- and greenhouse gas-based LCA of biofuel and bioenergy systems: Key issues, ranges and
recommendations. Resources, Conservation and Recycling, 53(8), 434–447.
doi:10.1016/j.resconrec.2009.03.013
Croezen, H. J., Bergsma, G. C., & Koot, M. C. M. (2006). Is er een vruchtbare toekomst voor groene
grondstoffen in Nederland? CE Delft.
Dones, R. (2001). Life cycle inventories of energy systems. Swiss Centre for Life Cycle Inventories.
Eerhart, A. J. J. E., Faaij, A. P. C., & Patel, M. K. (2012). Replacing fossil based PET with biobased PEF;
process analysis, energy and GHG balance. Energy & Environmental Science, 5(4), 6407.
doi:10.1039/c2ee02480b
Ekvall, T., & Weidema, B. P. (2004). System boundaries and input data in consequential life cycle
inventory analysis. The International Journal of Life Cycle Assessment, 9(3), 161–171.
doi:10.1007/BF02994190
Eleni, R., & Panagiotis, A. (2006). Minimization of fuel consumption through optimum material
selection of a car frame production company (Vol. 1, pp. 189–195). WIT Press.
doi:10.2495/EEIA060191
Energy technology perspectives 2006 : in support of the G8 Plan of Action : scenarios and strategies to
2050. (2006). Paris: OECD/IEA.
Evans, A., Strezov, V., & Evans, T. J. (2010). Sustainability considerations for electricity generation
from biomass. Renewable and Sustainable Energy Reviews, 14(5), 1419–1427.
doi:10.1016/j.rser.2010.01.010
Finnveden, G. (2000). On the Limitations of Life Cycle Assessment and Environmental Systems
Analysis Tools in General. Int. J. LCA, 5(4), 229–238.
Finnveden, Göran, Hauschild, M. Z., Ekvall, T., Guinée, J., Heijungs, R., Hellweg, S., Koehler, A., et al.
(2009). Recent developments in Life Cycle Assessment. Journal of Environmental Management, 91(1),
1–21. doi:10.1016/j.jenvman.2009.06.018
Frischknecht, R., & Jungbluth, N. (2007). Overview and methodology. Swiss Centre for Life Cycle
Inventories.
Gnansounou, E., & Dauriat, A. (2010). Techno-economic analysis of lignocellulosic ethanol: A review.
Bioresource Technology, 101(13), 4980–4991. doi:10.1016/j.biortech.2010.02.009
GTC technology. (910, BTP-En). Value maximization for ethylene cracker - Pygas upgrading.
Gustavsson, L., Börjesson, P., Johansson, B., & Svenningsson, P. (1995). Reducing CO2 emissions by
substituting biomass for fossil fuels. Energy, 20(11), 1097–1113. doi:10.1016/0360-5442(95)00065-O
56

Harmelink, M., Bosselaar, L., Gerder, J., Boonekamp, P., Segers, R., Pouwelse, H., & Verdonk, M.
(2012, September). Berekening van de CO2-emissies, het primair fossiel energiegebruik en het
rendement van elektriciteit in Nederland. Agentschap NL.
Harmsen, P. F. ., & Hackmann, M. (2012). Groene bouwstenen voor biobased plastics biobased routes
en marktontwikkeling. Wageningen: Wageningen UR Food & Biobased Research.
Hipolito, M. G. (2011, June). Life Cycle Assessment of platform chemicals from fossil and
lignocellulosic biomass scenarios. Norwegian University of Science And Technology.
Hochhauser, A. M. (2004). Gasoline and Other Motor Fuels. In John Wiley & Sons, Inc. (Ed.), Kirk-
Othmer Encyclopedia of Chemical Technology. Hoboken, NJ, USA: John Wiley & Sons, Inc. Retrieved
from http://doi.wiley.com/10.1002/0471238961.0701191508150308.a01.pub2
Holladay, J. E., White, J. F., Bozell, J. J., & Johnson, D. (2007, October). Top Value Added Chemicals
from Biomass Volume II. US DOE.
Huber, G. W., & Corma, A. (2007). Synergies between Bio- and Oil Refineries for the Production of
Fuels from Biomass. Angewandte Chemie International Edition, 46(38), 7184–7201.
doi:10.1002/anie.200604504
Huber, G. W., Iborra, S., & Corma, A. (2006). Synthesis of Transportation Fuels from
Biomass: Chemistry, Catalysts, and Engineering. Chemical Reviews, 106(9), 4044–4098.
doi:10.1021/cr068360d
ICIS (2012). US shale gas boom to lead to petrochemical bust.
http://www.icis.com/blogs/editorscommentary/2012/02/us-shale-gas-boom-to-lead-topetrochemical-bust.html
ICIS (2012). Indicative chemical prices A-Z. http://www.icis.com/chemicals/channel-info-chemicals-az/
Inaba, M., Murata, K., Saito, M., & Takahara, I. (n.d.). Production of Chemical Compound from Bio-
Ethanol by Zeolite Catalysts (pp. 866–872). IEEE. doi:10.1109/ECODIM.2005.1619369
Iribarren, D., Peters, J. F., & Dufour, J. (2012). Life cycle assessment of transportation fuels from
biomass pyrolysis. Fuel, 97, 812–821. doi:10.1016/j.fuel.2012.02.053
Jong, de, E., Higson, A., Walsh, P., & Wellish, M. (2012). Bio-based Chemicals Value Added Products
from Biorefineries. IEA Bioenergy.
Jungbluth, N. (2007). Life cycle inventories of bioenergy. Swiss centre for life cycle inventories. p.
368-373
Kitzing, L., Mitchell, C., & Morthorst, P. E. (2012). Renewable energy policies in Europe: Converging or
diverging? Energy Policy, 51, 192–201. doi:10.1016/j.enpol.2012.08.064
Ko, C.-H., Wang, Y.-N., Chang, F.-C., Chen, J.-J., Chen, W.-H., & Hwang, W.-S. (2012). Potentials of
lignocellulosic bioethanols produced from hardwood in Taiwan. Energy.
doi:10.1016/j.energy.2012.06.026
57

Kotasthane, A. N., Balakrishnan, I., Shiralkar, V. P., Chandwadkar, A. J., Kulkarni, S. B., & Ratnasamy,
P. (1983). MANUFACTURE OF BTX AROMATICS FROM NON-PETROLEUM RAW MATERIAL. Indian
Journal of Technology, 21(6), 218–221.
Kroschwitz, J. I., Seidel, A., & Wiley InterScience (Online service). (2004). Kirk-Othmer encyclopedia of
chemical technology. Hoboken, N.J.: Wiley-Interscience. Retrieved from
http://dx.doi.org/10.1002/0471238961
Ladanai, S., & Vinterbäck, J. (2009). Global Potential of Sustainable Biomass for Energy. SLU.
Landini, D. (2003). Phase transfer catalysis (PTC): search for alternative organic solvents, even
environmentally benign. Journal of Molecular Catalysis A: Chemical, 204-205, 235–243.
doi:10.1016/S1381-1169(03)00304-2
Langeveld, H., Meeusen, M., & Sanders, J. (2010). The biobased economy biofuels, materials and
chemicals in the post-oil era. London; Washington, DC: Earthscan. Retrieved from
http://public.eblib.com/EBLPublic/PublicView.do?ptiID=517196
Link, S., Arvelakis, S., Paist, A., Martin, A., Liliedahl, T., & Sjöström, K. (2012). Atmospheric fluidized
bed gasification of untreated and leached olive residue, and co-gasification of olive residue, reed,
pine pellets and Douglas fir wood chips. Applied Energy, 94, 89–97.
doi:10.1016/j.apenergy.2012.01.045
Liptow, C., & Tillman, A.-M. (2009). Comparative life cycle assessment of polyethylene based on
sugar ane and crude oil. Chalmers University of technology, Dep. of Energy and Environment. Report
no 2009:14.
Logsdon, J. E. (2004). Ethanol. In John Wiley & Sons, Inc. (Ed.), Kirk-Othmer Encyclopedia of Chemical
Technology. Hoboken, NJ, USA: John Wiley & Sons, Inc. Retrieved from
http://doi.wiley.com/10.1002/0471238961.0520080112150719.a01.pub2
Ma, L., Wang, T., Liu, Q., Zhang, X., Ma, W., & Zhang, Q. (2012). A review of thermal–chemical
conversion of lignocellulosic biomass in China. Biotechnology Advances, 30(4), 859–873.
doi:10.1016/j.biotechadv.2012.01.016
Mathiesen, B. V., Münster, M., & Fruergaard, T. (2009). Uncertainties related to the identification of
the marginal energy technology in consequential life cycle assessments. Journal of Cleaner
Production, 17(15), 1331–1338. doi:10.1016/j.jclepro.2009.04.009
McKinney, M.L., Schoch, R.M., Yonavjak, L.; 2007; Environmental Science: Systems and Solutions; Jones and
Bartlett Publishers, sections 10.4 and 13.2
Mihalcik, D. J., Mullen, C. A., & Boateng, A. A. (2011). Screening acidic zeolites for catalytic fast
pyrolysis of biomass and its components. Journal of Analytical and Applied Pyrolysis, 92(1), 224–232.
doi:10.1016/j.jaap.2011.06.001
Naik, S. N., Goud, V. V., Rout, P. K., & Dalai, A. K. (2010). Production of first and second generation
biofuels: A comprehensive review. Renewable and Sustainable Energy Reviews, 14(2), 578–597.
doi:10.1016/j.rser.2009.10.003
58

Nigam, P. S., & Singh, A. (2011). Production of liquid biofuels from renewable resources. Progress in
Energy and Combustion Science, 37(1), 52–68. doi:10.1016/j.pecs.2010.01.003
Patzek, T. W., & Pimentel, D. (2005). Thermodynamics of Energy Production from Biomass. Critical
Reviews in Plant Sciences, 24(5-6), 327–364. doi:10.1080/07352680500316029
Peacocke GVC, Bridgwater AV, Brammer JG. (2004). Techno-economic assessment of power
production from the Wellman Process Engineering Ltd and BTG fast pyrolysis processes. Science in
Thermal and Chemical Biomass Conversion (ed. Bridgwater AV, Boocock DGB.), pp. 1785-1802, (CPL
Press)
Pelofsky, A. L., Greene, M. I., & LaDelfa, C. J. (1977). Direct production of methane and benzene from
coal. Energy Communications, 3(3), 253–272.
Phanphanich, M., & Mani, S. (2011). Impact of torrefaction on the grindability and fuel characteristics
of forest biomass. Bioresource Technology, 102(2), 1246–1253. doi:10.1016/j.biortech.2010.08.028
Pimentel, D. (n.d.). Ethanol fuels: Energy balance, economics, and environmental impacts are
negative. Natural Resources Research, 21(2), 127–134.
PPE (2011). The Future of Benzene and Para-Xylene after Unprecedented Growth In 2010.
http://www.chemsystems.com/about/cs/news/items/PPE%20PCMD%20Aromatics%202011.cfm
Ragauskas, A. J. (2006). The Path Forward for Biofuels and Biomaterials. Science, 311(5760), 484–489.
doi:10.1126/science.1114736
Sanchez, S. T., Woods, J., Akhurst, M., Brander, M., O’Hare, M., Dawson, T. P., Edwards, R., et al.
(2012). Accounting for indirect land-use change in the life cycle assessment of biofuel supply chains.
Journal of The Royal Society Interface, 9(71), 1105–1119. doi:10.1098/rsif.2011.0769
Sunde, K., Brekke, A., & Solberg, B. (2011). Environmental Impacts and Costs of Hydrotreated
Vegetable Oils, Transesterified Lipids andWoody BTL—A Review. Energies, 4(6), 845–877.
doi:10.3390/en4060845
Swain, P. K., Das, L. M., & Naik, S. N. (2011). Biomass to liquid: A prospective challenge to research
and development in 21st century. Renewable and Sustainable Energy Reviews, 15(9), 4917–4933.
doi:10.1016/j.rser.2011.07.061
Sweeney, W. A., & Bryan, P. F. (2008). BTX Processing. Kirk-Othmer Encyclopedia of Chemical
Technology (pp. 1–17). John Wiley & Sons, Inc.
Tijmensen, M. (2002). Exploration of the possibilities for production of Fischer Tropsch liquids and
power via biomass gasification. Biomass and Bioenergy, 23(2), 129–152. doi:10.1016/S0961-
9534(02)00037-5
Treasure, T., Gonzalez, R., Venditti, R., Pu, Y., Jameel, H., Kelley, S., & Prestemon, J. (2012). Coproduction
of electricity and ethanol, process economics of value prior combustion. Energy
Conversion and Management, 62, 141–153. doi:10.1016/j.enconman.2012.04.002
59

Unruh, D., Pabst, K., & Schaub, G. (2010). Fischer−Tropsch Synfuels from Biomass: Maximizing Carbon
Efficiency and Hydrocarbon Yield. Energy & Fuels, 24(4), 2634–2641. doi:10.1021/ef9009185
US DOE EERE. (2000). The BTX chain: Benzene, Toluene, Xylene. Energy and Environmental Profile of
the US Chemical Industry. US DOE EERE.
Valle, B., Gayubo, A. G., Aguayo, A. T., Olazar, M., & Bilbao, J. (2010). Selective Production of
Aromatics by Crude Bio-oil Valorization with a Nickel-Modified HZSM-5 Zeolite Catalyst. Energy &
Fuels, 24(3), 2060–2070. doi:10.1021/ef901231j
Vandelden, M., Kuipers, N., & Dehaan, A. (2006). Selection and evaluation of alternative solvents for
caprolactam extraction. Separation and Purification Technology, 51(2), 219–231.
doi:10.1016/j.seppur.2006.02.003
Wang, C., Hao, Q., Lu, D., Jia, Q., Li, G., & Xu, B. (2008). Production of Light Aromatic Hydrocarbons
from Biomass by Catalytic Pyrolysis. Chinese Journal of Catalysis, 29(9), 907–912. doi:10.1016/S1872-
2067(08)60073-X
Wang, H., & Chen, H.-Z. (2007). A novel method of utilizing the biomass resource: Rapid liquefaction
of wheat straw and preparation of biodegradable polyurethane foam (PUF). Journal of the Chinese
Institute of Chemical Engineers, 38(2), 95–102. doi:10.1016/j.jcice.2006.10.004
Wegener, G., Brandt, M., Duda, L., Hofmann, J., Klesczewski, B., Koch, D., Kumpf, R.-J., et al. (2001).
Trends in industrial catalysis in the polyurethane industry. Applied Catalysis A: General, 221(1-2),
303–335. doi:10.1016/S0926-860X(01)00910-3
Willems, P. A. (2009). The Biofuels Landscape Through the Lens of Industrial Chemistry. Science,
325(5941), 707–708. doi:10.1126/science.1175502
Williams, C. L., Chang, C.-C., Do, P., Nikbin, N., Caratzoulas, S., Vlachos, D. G., Lobo, R. F., et al. (2012).
Cycloaddition of Biomass-Derived Furans for Catalytic Production of Renewable p -Xylene. ACS
Catalysis, 935–939. doi:10.1021/cs300011a
Xie, X., Wang, M., & Han, J. (2011). Assessment of Fuel-Cycle Energy Use and Greenhouse Gas
Emissions for Fischer−Tropsch Diesel from Coal and Cellulosic Biomass. Environmental Science &
Technology, 45(7), 3047–3053. doi:10.1021/es1017703
Yang, Y., Hu, C., & Abu-Omar, M. M. (2012). Conversion of carbohydrates and lignocellulosic biomass
into 5-hydroxymethylfurfural using AlCl3·6H2O catalyst in a biphasic solvent system. Green
Chemistry, 14(2), 509. doi:10.1039/c1gc15972k
Yazdani, D., Shahnazi, S., Rezazadeh, S., & Pirali Hamadani, M. (n.d.). Review on yew tree (Taxus
spp.). Journal of Medical Plants, 4(15), 1–8.
Zabaniotou, A., & Kassidi, E. (2003). Life cycle assessment applied to egg packaging made from
polystyrene and recycled paper. Journal of Cleaner Production, 11(5), 549–559. doi:10.1016/S0959-
6526(02)00076-8
Zhong, Z. W., Song, B., & Zaki, M. B. M. (2010). Life-cycle assessment of flash pyrolysis of wood
waste. Journal of Cleaner Production, 18(12), 1177–1183. doi:10.1016/j.jclepro.2010.03.017
60

Appendix A: LCA polystyrene cup
The polystyrene cup was modelled in SimaPro using the Ecoinvent v2.2 database.
Table 10 shows the inventory for the model, consisting of expandable polystyrene, injection
moulding of said styrene, transport and curb side collection.
Table 10: inventory PS cup LCA
Phase process/product value unit
production Polystyrene, expandable, at plant/RER S 0.1 kg
production injection moulding/RER S 0.1 kg
use Transport, lorry, 16-32t, EURO3/RER S 0.0001 tkm
Waste Curb side collection/RER S 0.1 kg
Figure 15 shows the network for the single score impact of the life cycle stages, showing that the
polystyrene production has the largest impact, followed by the injection moulding and
incineration/waste phase.
Figure 15: Network overview of single score impac polystyrene cup LCA
61

Appendix B: inventories
For the inputs of biomass, coal, gas and oil higher heating values were used to convert them from the
units in Ecoinvent/other sources to MJ. For data from Ecoinvent, both “coal, brown, in ground” and
“coal, hard, unspecified” are combined as “coal”; “gas, natural, in the ground” is “gas”; “oil, crude, in
the ground” is oil. For use in the model and for calculating energy efficiencies, the higher heating
values of coal (22.7 MJ/kg, average of values in Key Energy Statistics 2007), natural gas (38.7 MJ/m3,
average of values in Key energy statistics 2007) and crude oil (42.9 MJ/kg, average of values in Key
Energy Statistics 2007) are used to convert the given units into energy units. The higher heating value
of wood is assumed to be 18.5 MJ/kg
Detailed inventory of chapter 6
FDCA from corn
The data for FDCA production were obtained from Eerhart 2012, using an average of the six cases
they calculated. The land use is based on 0.23 ha needed per t of PEF; per t of PEF 0.85 t FDCA is
needed.
Table 11
Source Eerhart 2012
Includes cradle-to-gate
IN OUT
14.8 MJ fossil resources 1 kg FDCA
0.97 m 2 land 0.85 kg CO 2
Per mole of product, the in-and outputs are the following:
Table 12
Source Eerhart 2012
Includes cradle-to-gate
IN OUT
2.31 MJ fossil resources 1 mole FDCA
0.3 m 2 land 0.13 kg CO 2
Biomass-based purified terephthalic acid
The data for biomass-based TA production were based on biomass-based xylene production as
described on page. Economic allocation was used to determine the in- and outputs of biomass-based
xylene production.
Using economic allocation, the emissions per kg of xylene are
Table 13
Source calculations
Includes cradle to distilled xylene
IN OUT
8.28 MJ fossil resources 1 kg xylene
136 MJ biomass 0.53 kg CO 2
5.58 m 2
land
To determine the in- and outputs of the rest of the TA production process, the datasets for fossil
terephthalic acid and fossil xylene were used. Per kg of TA, 0.66kg of xylene is needed. Thus, the in-
62

and outputs of 0.66 kg xylene production were subtracted from the in- and outputs of 1 kg of fossil
TA production.
The in-and outputs of the purified terephthalic acid process are:
Table 14
Source ecoinvent v 2.2
Includes cradle-to-gate
IN OUT
56.7 MJ fossil resources 1 kg PTA
0.69 MJ renewable energy 1.5 kg CO 2
The in-and outputs of the fossil-based xylene process process are:
Table 15
Source Ecoinvent v2.2 “xylene, at plant, RER/S”
Includes Cradle-to-gate
IN OUT
56 g coal 1 Kg xylene
679 dm 3
natural gas 1.3 kg CO2 803 g oil
0.2 MJ Renewable energy
The in-and outputs of the purified terephthalic acid minus the in- and outputs of the fossil xylene
process process are:
Table 16
Source calculation
Includes TA process-0.66 kg xylene process
IN OUT
13.6 MJ fossil resources 1 kg PTA-xylene
0.56 MJ renewable energy 0.677 kg CO 2
For the total in- and outputs of biomass-based TA production, the in- and outputs of 0.66 kg biomassbased
xylene production were added to the “TA-fossil xylene” in- and outputs.
Table 17
Source calculation
Includes TA process+0.66 kg biomass-based xylene process
IN OUT
19.1 MJ fossil resources 1 kg biomass-based PTA
0.56 MJ renewable energy 0.68 kg CO 2
90.2 MJ biomass
Per mole of product this is:
Table 18
Source calculation
Includes TA process+0.66 kg biomass-based xylene process
IN OUT
3.16 MJ fossil resources 1 mole biomass-based PTA
0.09 MJ renewable energy 0.17 kg CO 2
15 MJ biomass
63

FDCA from poplar
The data for production of FDCA from poplar were obtained from Eerhart 2012, Yang 2012 and
Ecoinvent. Yang (2012) describes the production of HMF from poplar, yielding 0.082 g of HMF per g
of poplar. The molecular weight of HMF is 126g/mol.
Table 19
Source Yang 2012
Includes poplar to HMF
IN OUT
1 kg poplar 0.082 kg HMF
From ecoinvent v2.2 “woodchips, softwood, at forest” was used to model the in- and outputs of
poplar.
Table 20
Source Ecoinvent v2.2 “woodchips, softwood, at forest”
Includes biomass production
IN OUT
4.1 g coal 1 kg woodchips
1.27 dm 3
natural gas 0.030 kg CO2 6.9 g oil
19.1 MJ Biomass
0.70 m 2 land
It was assumed that the production process of HMF from poplar was similar to that of fructose
production from corn, which is probably an underestimation. The in- and outputs of HMF oxidation
are provided by Eerhart 2012.
Table 21
Source Eerhart 2012
Includes HMF oxidation
IN OUT
1 kg HMF 1.24 kg FDCA
11.8 MJ fossil resources 0.68 kg CO 2
The in- and outputs of the HMF production from corn are:
Table 22
Source Eerhart 2012
Includes fructose from corn
IN OUT
10.5 MJ fossil resources 1 kg fructose
0.63 kg CO 2
Combining the datasets above, the in- and outputs per kg of FDCA from poplar are:
Table 23
Source calculations
Includes cradle-to-gate
IN OUT
188 MJ biomass 1 kg FDCA
22.33 MJ fossil resources 1.35 kg CO 2
And per mole of product:
64

Table 24
Source calculations
Includes cradle-to-gate
IN OUT
29.3 MJ biomass 1 mole FDCA
3.48 MJ fossil resources 0.21 kg CO 2
Detailed inventory chapter 7
Fossil electricity
The data for fossil electricity were obtained from data by Agentschap NL on electricity production in
the Netherlands in 2010 for fossil resource use and CO2 emissions of average electricity production in
the Netherlands. Their system only considers the power plant itself and not mining, transport etc.,
which they estimate accounts for an additional 5.26% of emissions and resources. Therefore, their
data were multiplied by 1.0526 to obtain cradle to grave emissions and resource needs.
Table 15
Source Harmelink 2012
Includes Plant in- and outputs
IN OUT
2.02 MJ Fossil resources 1 MJ electricity
0.124 kg CO 2
Table 26
Source Harmelink 2012/0.95
Includes Cradle-to-gate
IN OUT
2.13 MJ Fossil resources 1 MJ electricity
0.130 kg CO 2
Fossil diesel
The data for fossil diesel production were obtained from Ecoinvent v 2.0, using the input “Diesel, at
refinery, RER/S”. The Ecoinvent data encompasses cradle-to-gate in- and outputs.
Table 27
Source Ecoinvent v2.2
Includes Cradle-to-gate
IN OUT
47 g coal 1 Kg Diesel
55 dm 3
natural gas 0.436 kg CO2 1100 g oil
0.1 MJ Renewable energy
Fossil ethanol
The data for fossil ethanol production were obtained from Econinvent v 2.0, using the input “ethanol
from ethylene, at plant, RER/S”. The Ecoinvent data encompasses cradle-to-gate in- and outputs.
65

Table 28
Source Ecoinvent v2.2
Includes Cradle-to-gate
IN OUT
80 g coal 1 Kg ethanol
436 dm 3
natural gas 1.060 kg CO2 609 g oil
0.3 MJ Renewable energy
Fossil BTX
The data for fossil BTX production were obtained from Ecoinvent v 2.0, using the inputs “benzene, at
plant, RER/S”, “toluene, liquid, at plant, RER/S”, “xylene, at plant, RER/S”.
Table 29
Source Ecoinvent v2.2 “benzene, at plant, RER/S”
Includes Cradle-to-gate
IN OUT
57 g coal 1 Kg benzene
631 dm 3
natural gas 1.5 kg CO2 877 g oil
0.19 MJ Renewable energy
Table 30
Source Ecoinvent v2.2 “toluene, liquid, at plant, RER/S”
Includes Cradle-to-gate
IN OUT
41 g coal 1 Kg toluene
666 dm 3
natural gas 1.2 kg CO2 776 g oil
0.14 MJ Renewable energy
Table 31
Source Ecoinvent v2.2 “xylene, at plant, RER/S”
Includes Cradle-to-gate
IN OUT
56 g coal 1 Kg xylene
679 dm 3
natural gas 1.3 kg CO2 803 g oil
0.2 MJ Renewable energy
Using the demand ratio given by Sweeney (2007), 67:5:28, the weighted average in- and outputs for
BTX according to the demand ratio were calculated. So (inputs BTX)=0.67x(inputs
benzene)+0.05x(inputs toluene)+0.28x(inputs xylene). The Ecoinvent data encompasses cradle-togate
in- and outputs.
Table 32
Source BTX 67:5:28 ratio
Includes Cradle-to-gate
IN OUT
55.9 g coal 1 Kg BTX
646 dm 3
natural gas 1.4 kg CO2 851 g oil
0.9 MJ Renewable energy
66

Fossil ethylene
The data for fossil ethylene production were obtained from the technical report of the Ecoinvent v
2.2 database “plastics”, using the ethylene production data. The Ecoinvent data encompasses cradleto-gate
in- and outputs.
Table 33
Source technical document ethylene by ecoinvent v2.2
Includes Cradle-to-gate
IN OUT
4.2 g coal 1 Kg ethylene
537 dm 3
natural gas 1.1 kg CO2 927 g oil
0.16 MJ Renewable energy
Biomass electricity
The data for biomass electricity production were obtained from Ecoinvent v 2.2, using the input
“wood pellets electricity CH/S”.
Table 34
Source Ecoinvent v2.2 “wood pellets electricity CH/S”
Includes Cradle?-to-gate
IN OUT
16 g coal 1 MJ electricity
3.2 dm 3
natural gas 0.037 kg CO2 3.7 g oil
4.85 MJ Biomass
38 MJ other renewable energy
Biomass diesel
The data for biomass diesel production were obtained from Ecoinvent v 2.2, using the input “syngas
from wood, fluidized bed reactor, CH/S” for the in- and outputs of syngas production, and 71%
energy efficiency for the conversion of syngas to liquid fuel (Swain). It is assumed that the
exothermic Fischer-Tropsch synthesis of diesel from syngas does not require additional inputs and
has no emissions. The obtained value for CO2 emissions (380g/kg diesel) is in the same range as
values found in literature: Roedl 402 g/kg diesel and Searcy 237-792 g/kg diesel.
Table 35
Source Ecoinvent v2.2 “syngas from wood, fluidized bed reactor, CH/S”
Includes Cradle-to-syngas
IN OUT
7.6 g coal 1 m 3 syngas
2.7 dm 3
natural gas 0.033 kg CO2 6.44 g oil
11.2 MJ Biomass
0.5 MJ other renewable energy
Syngas has a higher heating value of 5.4 MJ/m 3 . Converion of syngas to diesel has an energy
efficiency of 71%. So for the production of 1 kg diesel (HHV 44 MJ/kg) 11.5 m 3 of syngas is needed
67

Table 36
Source Ecoinvent v2.2 “wood pellets electricity CH/S”, Swain
Includes Cradle-to-gate
IN OUT
86 g coal 1 kg diesel
31 dm 3
natural gas 0.377 kg CO2 74 g oil
128 MJ Biomass
5.7 MJ other renewable energy
Biomass ethanol
The data for biomass ethanol production were obtained from Econinvent v2.2, using partly the input
“ethanol from wood, CH/s” and partly the technical document on that dataset. The fossil resource
needs and CO2 emissions of wood ethanol production were obtained from the dataset, whilst the
biomass required was obtained from the technical document, since there was a significant
discrepancy between biomass requirements found in literature and the biomass input into the
dataset.
Table 37
Source technical document ethanol from wood Ecoinvent v2.2
Includes ethanol process
IN OUT
6.94 kg wood 1 kg ethanol
This 6.94 kg input/kg ethanol is the average value of several studies.
Table 38
Source Ecoinvent v2.2 “ethanol from wood”
Includes Cradle-to-gate, without biomass input
IN OUT
29.91 g coal 1 kg ethanol
56.8 dm 3
natural gas 0.389 kg CO2 81.7 g oil
Combining the two datasets above, the inputs and emissions for one kg of ethanol are:
Table 39
Source Ecoinvent v2.2 “ethanol from wood” and its technical document
Includes Cradle-to-gate
IN OUT
29.91 g coal 1 kg ethanol
56.8 dm 3
natural gas 0.389 kg CO2 81.7 g oil
129 MJ Biomass
Biomass BTX
The data for biomass BTX production were obtained from several sources. For the biomass feedstock,
from Ecoinvent v2.2 “woodchips, softwood, at forest” was used.
68

Table 40
Source Ecoinvent v2.2 “woodchips, softwood, at forest”
Includes biomass production
IN OUT
4.1 g coal 1 kg woodchips
1.27 dm 3
natural gas 0.030 kg CO2 6.9 g oil
19.1 MJ Biomass
Table 41
Source Phanphanich 2011
Includes torrefaction and grinding
IN OUT
1 kg woodchips 1 kg wood powder
0.09 MJ fossil resources 0.01 kg CO 2
For the pyrolysis process, including recycling of waste biomass for heat production and purification of
the product, data from (achtergrond artikel ZHong) was used. For the BTX yield from the process,
Mihalick (2011?) was used, which also provided a ratio of BTX yield for hardwood. Electricity in and
outputs are assumed to be the same as for the process chain “fossil electricity”
Table 42
Source Peacocke 2004, Mihalick 2011
Includes biomass pysolysis to BTX mix (29.1:22.6:48.3)
IN OUT
139.3 MJ biomass 1 kg BTX mix
2.2 MJ electricity
For the separation of BTX into the individual chemicals, data from (pygas upgrading) was used. CO2
emissions based on emissions of burning 0.79MJ diesel to power distillation process
Table 43
Source GTC technology
Includes distillation of BTX
IN OUT
1 kg BTX mix 0.291 kg benzene
0.79 MJ fossil resources 0.226 kg toluene
0.483 kg xylene2.6
0.06 kg CO 2
Since the pyrolysis process yielded a different ration of BTX than demanded, data from US DOE
(2000) were used to determine the in- and outputs of xylene and toluene dehydroalkylation into
benzene. For the separation and dehydroalkylation steps, the CO2 emissions associated with the
energy input were assumed to be the same as emissions from combustion of an equal amount of
diesel.
Table 44
Source EERE
Includes hydrodealkylation process
IN OUT
0.188 kg toluene 0.324 kg benzene
0.224 kg xylene 0.01 kg CO 2
Because the total BTX yield is now 7.5% too low (the high xylene fraction means the mole yield is
relatively low), the whole process needs to be multiplied by 1.08, giving:
69

Table 45
Source calculations
Includes cradle-to-gate
IN OUT
10.97 MJ fossil resources 1 kg BTX demand ratio
155.36 MJ biomass 0.72 kg CO 2
Biomass ethylene
The data for biomass ethylene production were obtained from the same sources as biomass ethanol
production. For the dehydration of ethanol data from (Hishier 2007) were used.
Table 46
Source Capello 2009
Includes dehydration including purification etc.
IN OUT
1 kg ethanol 0.68 kg ethylene
8.26 MJ fossil resources 0.58 kg CO 2
The ethylene yield is only 0.68 kg per kg ethanol input, since a water molecule is lost in the process.
Combining therefore 1.47 times the dataset of biomass-based ethanol production and 1.47 times the
dehydration process, the following data are obtained for biomass-based ethylene production:
Table 47
Source calculations
Includes cradle-to-gate
IN OUT
21.46 MJ fossil resources 1 kg ethylene
189 MJ biomass 1.4 kg CO 2
70

Appendix C: Uncertainty determination
The table below shows the uncertainty factors for each of the inventory items in the appendixes
above.
The table number 48 shows to which table/item the entry refers, in case the description is unclear.
Rows 3-9 show the individual factors for each of the items in the Pedigree matrix of uncertainty
(Frischknecht & Jungbluth, 2007). This matrix is a tool with which to determine the uncertainty in LCI,
further described in the reference. The letters correspond to the following factors:
R: Reliability (how accurate are the data measurements)
C: Completeness (was the general scope large enough?)
T: Temporal (how recent is the data?)
G: Geographic (is the data from the right region?)
F: Further technological correlation (is the used data of the very technology being studied?)
S: Sample size
B: Basic indicator
When all these individual factors have been assigned, the total uncertainty factor (or square
geometric standard deviation) is calculated by means of the formula (Frischknecht & Jungbluth,
2007):
With U1-U6 being the uncertainty factors mentioned above.
The basic indicator was 1 in most cases, but in some cases it was larger than 1. For fossil-based
electricity, the basic uncertainty is 1.1, to account for the choice of using average rather than
marginal data. For the efficiency of the conversion of syngas to fossil diesel the basic uncertainty
factor is 1.2, since only the basic energy efficiency of conversion was used, not process energy and
emissions as well. For the amount of ethanol obtainable from wood, the basic uncertainty factor is
1.22, a figure derived from the deviation from the average as deduced from the source of the data
(Jungbluth, 2007). For woodchip production there was a basic uncertainty factor of 1.1, since
woodchips are but one of many possible inputs of wood into the biomass-based BTX system. Finally,
FDCA from corn had an additional uncertainty in fossil resource use that is not expressed in the
uncertainty factor but is taken into account in the error margin, which is 3.9 MJ/kg. This figure was
based on using a different feedstock (corn from Germany rather than corn from the US).
With the total factor of each input table known, the uncertainty margins were based on a calculation
of the highest and lowest values for each process.
71

Table 28: uncertainty factors inventory
What Table R C T G F S B Total
Fossil electricity 25 1 1 1 1.02 1 1 1.1 1,102
Fossil diesel 27 1 1 1 1 1 1.05 1.05
Fossil ethanol 28 1 1 1 1 1 1.05 1.05
Fossil benzene 29 1 1 1 1 1.2 1.05 1.207
Fossil xylene 30 1 1 1 1 1.2 1.05 1.207
Fossil toluene 31 1 1 1 1 1.2 1.05 1.207
Fossil BTX 32 1.207
Fossil ethylene 33 1 1 1 1 1 1.05 1.05
Biomass electricity 34 1.05 1.1 1 1.02 1 1.1 1.155
Biomass syngas 35 1 1.1 1 1.02 1 1.1 1.14
Biomass FT Swain 36 1.2
Biomass diesel 1.25
Biomass ethanol from
wood
37 1 1 1 1 1 1 1.22 1.22
Biomass ethanol process 38 1 1.1 1 1.02 1 1.1 1.145
Biomass woodchip 40 1 1.1 1 1.02 1 1.1 1.1 1.18
production
Biomass grinding 41 1.05 1 1 1 1 1.1 1.11
Biomass pyrolysis 42 1 1.05 1 1 1.2 1.1 1.23
Biomass distillation 43 1 1 1 1 1 1.1 1.1
Biomass hydrodealkylation 44 1 1.1 1 1 1 1.1 1.144
Biomass ethylene 46 1 1 1 1 1.2 1.1 1.228
FDCA from corn 12 1.05 1 1 1.1 1 1.1 * 1.15
Biomass PTA process 16 1 1 1 1 1 1.05 1.05
FDCA from poplar 19 1 1 1 1 1.2 1.1 1.23
HMF oxidation 21 1 1 1 1 1.2 1.2 1.29
Fructose production
process
22 1 1 1 1 1.5 1 1.5
72

Appendix D: Sensitivity chapter 6
The sensitivity of the results towards the input data was calculated by increasing the value of the
input data (amount required, fossil resource use and CO2 emissions) by a certain amount. The change
in the results divided by the change in the input values is the sensitivity. A very sensitive parameter
will give a greater change in the results when altered than a not so sensitive parameter. The figures
below (16-18) show the sensitivity of the different input parameters of the three processes of the
LCA in chapter 6.
Figure 16 sensitivity of TA production inventory
Figure 17: sensitivity of FDCA from corn production
73

Figure 18: sensitivity of FDCA from poplar production
74
60%
40%
20%
0%
-20%
-40%
-60%
-80%
-100%
-120%
woodchips
from
softwood
HMF
production
HMF from
poplar
HMF
oxidation
Fossil resource use
land use
CO2 emissions

Appendix E: Sensitivity chapter 7
The sensitivity of the results towards the input data was calculated by increasing the value of the
input data (amount required, fossil resource use and CO2 emissions) by a certain amount. The change
in the results divided by the change in the input values is the sensitivity. A very sensitive parameter
will give a greater change in the results when altered than a not so sensitive parameter. The figures
below (19 & 20) show the sensitivity of the different input parameters of the three processes of the
LCA in chapter 7.
190,00%
160,00%
130,00%
100,00%
70,00%
40,00%
10,00%
-20,00%
-50,00%
-80,00%
-110,00%
electricity
diesel
ethanol
ethylene
electricity
diesel
ethanol
ethylene
electricity
diesel
ethanol
biomass needed Biomass fosres en co2 Fossil fos res en co2
Figure 19: sensitivity of input parameters
110,00%
90,00%
70,00%
50,00%
30,00%
10,00%
-10,00%
-30,00%
-50,00%
-70,00%
-90,00%
-110,00%
Figure 20: sensitivity of input parameters BTX
ethylene
Fossil resource use
CO2 emissions
fossil resource use
CO2 emissions
75