3. FOOD ChEMISTRy & bIOTEChNOLOGy 3.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Food Chemistry & Biotechnology
L07 PREPARATION OF bIODIESEL FROM TALL
OIL
RADOSLAV MIKULáŠIK a , IGOR ŠURInA a ,
SVETOZáR KATUŠČáK a , Ján CVEnGROŠ b and
MARTIn POLOVKA c
Department of Chemical Technology of Wood, Pulp and
Paper, a Institute of Polymer Materials,
b Institute of Physical Chemistry and Chemical Physics, Faculty
of Chemical and Food Technology, Slovak University of
Technology,Radlinského 9, 812 37, Bratislava, Slovakia,
c Food Research Institute, Department of Chemistry and Food
Analysis, Priemyselná 4, 824 75, Bratislava, Slovakia,
radoslav.mikulasik@stuba.sk
Introduction
It has known that after delignification kraft pulping process
almost all extractable dissolved or emulsified substances
of wood pass into black liquor. Evaporation of water from
black liquor causes an increase in sodium salts content. Soaps
are settled on all places, where liquor remains motionless. Tall
soaps flowing on surface are separated in the form of foam
in all tanks and their amount increases with density of black
liquor 1–3 . Tall soap may be incinerated together with higherdensity
black liquor within chemicals recovery or separated
and utilised to high value chemicals. The latter alternative is
more cost effective 4 . Kraft tall soap (TS) may be converted
by acidification to tall oil (TO) and individual components
isolated from it by vacuum distilation.
TO is a dark brown, viscous and odorous liquid 5 containing
mainly higher fatty acids (HFA), resin acids (RA),
sterols and many other extractable substances 6 .
Very interesting is HFA content ranging from 26 to
58 % wt. 7 and depending mainly on the sort of wood. Given
the high amount of wood, which is delignificated in paper
mill in Central-european region, it represents a cheap raw
material for biodiesel production. Biodiesel is exclusively
produced from expensive vegetable oil.
This work is focused on biodiesel production from tall
oil and testing of selected biodiesel properties and their comparison
with En 14214 8 . A method based on esterification
straight by methanol and subsequent vacuum distillation of
methylesters HFA from mixture was chosen. The method
seems to be more advantageous than that based on esterification
of HFA fraction obtained preferentially by vacuum distillation
of TO. namely, boiling point of HFA methylesters is
lower than that of HFA.
Our method is more efficient from the viewpoint of
energy demands when compared with the method realised,
e.g., by AltÂparmak D., Keskin A., Koca A., Gürü M., 9 .
Experimental
M a t e r i a l s
Chemicals: sulphuric acid, 96 % wt., Microchem, SR,
Tall oil was prepared from aqueous solution of tall soap
supplied by MOnDI Packaging Paper Štětí, ČR.
s552
I n s t r u m e n t s , F a c i l i t i e s , M e t h o d s
Gas chromatography and mass spectrometry (GC/MS).
Analysis of tall oil composition was performed by GC/MS
with a Hewlett – Packard 5890A/5790B equipment.
GC conditions: column: PTE–5, 30 m, 0.25 mm ID,
0.25 μm film, carrier gas: helium, flow-rate 1 ml min –1 ,
pressure 50 kPa , purge off: 0 min (split), injection temperature:
275 °C, temperature of detector: 280 °C, temperature
program: 170 °C (3 min), 5 °C min –1 – 270 °C (9 min),
15 °C min –1 – 300 °C (3 min)
MS conditions: mass range: 43–550 amu, EMV: 2400 V,
threshold setting: 1000, SD: 3 min
IR spectroscopy. Infrared spectra of all specimens were
obtained by Digilab Excalibur FTS 3000MX – FTIR method.
Samples were measured by diffusion scatter method (DRIFT)
in KBr powder (5 % wt.).
Vacuum (molecular) distillation. A laboratory molecular
vacuum evaporator MO15 10 was used to isolate methylesters
HFA and also to purify this product.
Other laboratory equipment: furnace, balance, centrifuge,
vacuum rotary evaporator.
TO preparation from TS was carried out at following
conditions:
Table I
Conditions of tall oil preparation from tall soap
Mass TS ~ 1,000 g
Heating time TS 25 → 95 °C ~ 15 min.
H 2 SO 4 concentration 43.6 wt. %
Volume of added H 2 SO 4 solution 1.5 dm 3
Reaction time 200 min. (3.3 h)
Agitation intensive (3.3 h)
TO was consequently esterified at conditions:
Table II
Conditions of tall oil esterification by CH 3 OH
Conc. sulphuric acid [H 2 SO 4 , 96 % wt.] 5 % wt.
of the mass of HFA in TO
Temperature of reaction mixture 60 °C
Molar ratio of CH 3 OH to HFA in TO 6 : 1
Reaction time 5.5 h
Intensive agitation of reaction mixture 5.5 h
Table III
Properties of tall soap and tall oil
Dry matter [% wt.] 65.56
Ash [% wt.] 11.36
TO in TS [% wt.] 84.00
Acid number of prepared TO
[mg KOH g
154.70
–1 TO]