Biofuels in Perspective

154 Biofuels
One of the renewable resources for the production of ‘green energy’ are vegetable
oils and animal fats. Although today the major part of lipids is still used for human
food (80 %), animal feed (5 %) and industrial applications (15 %) it can be expected that
the use for industrial purposes and for energy supply will be growing in the very near
future.
The use of neat vegetable oils as transportation fuel has not been very successful in the
past due to the high viscosity which is causing engine problems such as injector and filter
coking and deposit formation. Expensive changes in diesel engines are necessary in order
to use vegetable oils as fuel. However, the use of vegetable oils and/or animal fats, neat or
as mixtures with diesel fuel, is a good alternative to be used in stationary diesel engines
for the production of ‘green electricity heat and power’. The best alternative in order to
approximate the physical and chemical properties and the engine performance of petroleum
based diesel is biodiesel. Biodiesel consists of esters of long chain fatty acids with short
chain alcohols. Fatty acid methyl esters (FAME) are most often used as biodiesel due to
the lower price of methanol in comparison with higher alcohols with the exception of the
use of ethanol for biodiesel production in Brazil. For the automotive industry biodiesel is
blended with the mineral diesel fuel.
Biofuels and biodiesel will not be able to solve the increasing energy demand. Apart from
biofuels derived from natural resources, new alternative ways of converting whole crops
have to be developed. Integral valorization in cogeneration plants are already producing
electricity and steam from palm oil and waste lipid resources.
In addition there are major barriers in the commercialization of biodiesel from lipids.
First, the primary use of vegetable oils will remain as a food ingredient. The increasing
world population and the growing standard of living in developing countries is leading to a
higher consumption of vegetable oils. The conflict between the use as human food/animal
feed on one hand, and fuel use on the other hand, is already affecting the world vegetable
oil market process.
The second obstacle for biodiesel commercialization are the high manufacturing costs
which are mainly due to the higher costs of the raw materials, especially the virgin vegetable
oils, but also to the cost of production. Both costs are dependent on the location, plant size,
the value of the byproducts (especially the glycerine production) and the environmental
conditions. In most cases, in order to reach the standards for biodiesel, the crude oils-fats
are the subject of an intensive refining process which is an additional cost factor in the final
biodiesel production.
At this moment the major raw materials for biodiesel production is food-grade canola
oil in Europe, soybean oil in North-South America and palm oil in South-East Asia and in
Africa.
Less expensive resources as raw material for biodiesel production are waste oils such
as waste cooking and frying oils, rendered animal fat, recuperated oils and side-streams
from the refining, next to the direct use of crude and non-refined vegetable oils and new
non-edible resources such as yatropha oil and lipids derived from micro-algae.
The aim of this chapter is to provide a ‘state-of-the-art’ overview of the conversion of
crude lipids, waste oils and alternative oil resources including the processing, additional
refining and applications.
Books and reviews dealing with the production of biodiesel are available and furnish
detailed information on the use of crude and refined oils and waste streams (Knothe, 2000;