86 Introduction to Renewable Biomaterials
Cracking:
Decarbonylation:
Decarboxylation:
Hydrocracking:
Hydrodeoxygenation:
Hydrogenation:
CH 2
CH 2
H 2 C
ROH
CH 2
C
C
O
OH
H H
CC
O
H
CH 2 CH
HCO
+
+
+
+
+ +
+
+
+
CH-R 2
CH 2
CH 2
CH 2
R 2
R 1
R 1
R 1
R 1
R 1
R 1 H CO 2
R H
CH 3
CH 2
CH 2
H 3 C
H 2 O
H 2 O
R 1
R 2
R 1
R 1 R^2
R 1
R 2
H 2
H 2
H 2
R 2
Figure 3.9Examples of reactions associated with catalytic bio-oil upgrading. Reproduced with
permission from: Mortensen PM, Grunwaldt JD, Jensen PA, Knudsen KG, Jensen AD. A review of
catalytic upgrading of bio-oil to engine fuels. Applied Catalysis A: General. 2011;407(1–2):1–19.
Copyright (2011) Elsevier.
remains a significant challenge. To address these problems, approaches to utilise bio-oil
as feedstock for other processes have been studied. Utilisation of bio-oil as a feed for
gasification and subsequent synthesis of hydrocarbons via FTS has been studied and
proved technically feasible [25]. Other applications of bio-oil include its use in parti-
cle boards as resins, as a carrier for slow-release organic fertiliser, wood preservative,
food additive and other niche applications [26]. In summary, bio-oil has an advantage of
storability and transportability and has already found applications as a renewable fuel for
boilers or furnaces. The most promising and valuable applications of bio-oil as a source
of fuels and chemicals are still under development, and significant advances in refining
and upgrading are still required to fulfil the potential of this technology.
3.4.7 Conversion of Oily Feedstocks
Oily feedstocks– triglycerides already possess long alkyl chains that are similar to those
of diesel molecules. This similarity resulted in different approaches to transform lipid
feedstocks than those used for whole lignocellulose biomass. An interest in using veg-
etable oil and its derivatives as a fuel can be dated back to the history of diesel engine
itself. The first demonstration of engine during the World Fair in Paris in year 1900 used
peanut oil as a fuel [28]. Currently, two approaches to derivatise oily feedstocks to fuel
molecules are used: transesterification and hydroprocessing.
Transesterification– Transesterification is relatively simple process, triglycerides are
reacted with a short-chain anhydrous alcohol (usually methanol or ethanol) using a cat-
alyst. During the reaction, glycerol moiety of the fatty acid is replaced with alkyl group
of an alcohol. After the reaction is complete, two products are formed: fatty acid alcohol
