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Introduction to extraction, refining and processing
Introduction to extraction, refining and processing
Shenhua’s direct coal liquefaction plant, the first of its kind in the world, has been in operation since 2008.
Ongoing research and development efforts are vital to the future of the petrochemicals industry.
and methane. The CO 2
is waste and other gases
can be burnt or processed further.
The second stage for liquefaction is the Fischer-
Tropsch process. Once the coal gas is filtered and
processed, the carbon monoxide and hydrogen
ratio is adjusted by the addition of water or carbon
dioxide. This hot gas is passed over a catalyst,
causing the carbon monoxide and hydrogen to
con dense into long hydrocarbon chains and water.
These chains can be used as an alternative to oil
products such as heating oil, kerosene and gasoline.
The water, meanwhile, can be recycled and
used as steam for the liquefaction process.
Aside from this two-stage process, coal can also
be liquefied via direct coal liquefaction (DCL). This
can take place as a one- or two-stage process. In
the 1960s, single-stage DCL techniques were pioneered
but these first-generation processes have
now been largely superseded or abandoned. The
single-stage processes attempted to convert coal
ded demonstration testing in 2008 and has been
operational ever since.
High-tech challenges
Simply continuing to churn out products we
already know how to make isn’t an option for companies
to remain competitive and profitable. Companies
need to create new products and find cheaper
ways to do things, which is why research and development
is important to petrochemical producers.
The chemical and manufacturing processes in
this part of the downstream business require a
huge pool of expertise – and a lot of money – to
ensure engineers and scientists continue to make
breakthroughs. The drive to produce more with
less, and more cheaply, provides researchers with
access to the sort of facilities rarely found beyond
the commercial sector.
Keeping costs down is vital, because the facilities are
expensive to build, maintain and run. Refiners and petroto
liquids with a single reaction stage, usually
involving an integrated hydrotreating reactor.
In DCL, the coal is put in direct contact with the
cat alyst at very high temperatures (850°F/455°C) in
the presence of additional hydrogen. This reac tion
takes place in the presence of a solvent. The solv ent
facilitates coal extraction. The solubi lised pro ducts,
which consist mainly of aromatic com pounds, then
may be upgraded by conven tional petro leum
refining techniques, such as hydro treating
DCL processes are more efficient than ICL but a
higher quality coal is required for best results.
How ever, since the late 1980s, very few DCl programmes
were continued with the exception of
HTI, now called Headwater Inc, has developed a
two-stage catalytic liquefaction process that was
funded by the US Department of Energy. This technology
was then licensed to China’s Shenhua
Corporation in 2002 for the construction of a
20,000 bpd plant in Inner Mongolia that commen-
chemical producers must also contend with ongoing
volatility in the prices of commodities, with forwardplanning
essential for years when margins are low.
Environmental issues are a vital part of research
in the sector, so firms have to focus on how the industry
can meet increasingly stringent stan dards
for cleaner refining and manu fac turing pro cesses,
and high health and environ men tal standards required
of the final products. These high standards
are often imposed at a self-regulatory level by the
companies themselves and by governments.
In the US, for example, which has more refining
capacity than any other nation on Earth, the sector
is, in the words of the US Department of Energy,
“one of the most heavily regulated industries.” If
refineries fail to comply, they cannot operate.
For alternatives to fossil fuel-based petrochemicals,
see page 102.
William Sripe is a freelance journalist.
28 WPC Guide
Petrochemicals and Refining 29