Page 126 - Biofuels Refining and Performance

Raw Materials to Produce Low-Cost Biodiesel 109

among some other countries, the Australian Senate approved an excise
exemption on biofuels in 2004. However, the tax exemption will one day
come to an end; in order to continue to promote the social inclusion and
economic attraction of biodiesel, other steps will be needed. This could be
facilitated by the selection of low-cost raw materials, such as nonedible
oils, used frying oil, or animal fat, and the use of a lower-cost transes-
terification process.
A lower-cost biodiesel production can be achieved by the optimization
of the process. Because the chemical properties of the esters determine
their feasibility as a fuel, the intent of the optimization is to investigate
and optimize the involved parameters maximizing the yield of ester,
to develop a low-cost chemical process, and to ensure appropriate oil
chemical properties for both the transesterification and the engine
performance.
Although it is a well-known process since, in 1864, Rochleder described
glycerol preparation through the ethanolysis of castor oil [33], the pro-
portion of reagents affects the process, in terms of conversion efficiency
[34]; this factor differs according to the vegetable oil. Several researchers
have identified the most important variables that influence the trans-
esterification reaction, namely, reaction temperature, type and amount
of catalyst, ratio of alcohol to vegetable oil, stirring rate, and reaction
time [20, 35–42]. In this sense, it is important to characterize the oil (i.e.,
fatty acid composition, water content, and peroxide value) to determine
the correlation between them and the feasibility to convert the oil into
biodiesel [39, 43].
However, several studies have identified that the price of feedstock
oils is by far one of the most significant factors affecting the economic
viability of biodiesel manufacture [30, 44–46]. Approximately 70–95%
of the total biodiesel production cost arises from the cost of the raw
material [44, 45]. To produce a competitive biodiesel, the feedstock price
is a factor that needs to be taken into consideration. Edible oils are too
valuable for human feeding to run automobiles. So, the accent must be
on nonedible oils and used frying oils.

4.2 Nonedible Oils
Among nonedible feedstock, there are many crops and tree-borne oilseed
plants, such as karanja, neem, and jatropha, which have been under-
utilized due to the presence of toxic components in their oils. Most of
them grow in underdeveloped and developing countries, where a
biodiesel program would give multiple benefits in terms of generation
of employment for rural people (farmers), leverage of starting many
types of industries using by-products from biofuels, and so forth [47].
However, nonedible crops are very much ignored in most cases. They