The conversion of oil crops to biofuels—Fatty Acid Methyl Esters (FAME), more commonly known as biodiesel involves processes like transesterification, where the vegetable oil is chemically reacted with an alcohol, in presence of a homog­enous or a heterogenous catalyst. In the catalytic conversion process, in turn the catalyst plays an important role in an oil seed biorefinery. Catalysts that selectively convert a particular substrate to the desired product and the catalytic reactor

parameters related to the design, operation, and control of the catalytic reactor are the key factors responsible for the development of an economically viable process. Chew et al. [42] have proposed a biorefinery based on palm oil and palm biomass for the production of biofuels. The conceptual biorefinery would consist of two plants. One plant would treat the solid portions of the Palm tree biomass whereas the other plant would treat the expressed oil portion. The solids processing plant will carry out liquefaction using supercritical water, pyrolysis, and gasification of the biomass, and the liquid/oil processing plant will carry out transesterification and catalytic cracking of the expressed oil portion of the palm biomass. The products of the biorefinery would comprise of different biofuels, gaseous hydro­carbons, hydrogen, glycerine, olefinic, and aromatic compounds. Figure 1.24 shows the scheme for such a biorefinery along with the various products obtained therein.

The catalytic processes proposed by them for the purpose include (a) catalytic cracking of palm oil for production of biodiesel, (b) production of hydrogen and

syngas from biomass gasification, (c) Fischer-Tropsh synthesis for conversion of syngas into liquid fuels, and (d) upgrading of liquid fuels obtained from lique — faction/pyrolysis of biomass. Catalyst plays a key role in all the above processes in terms of economy and product distribution. They have reviewed a number of catalysts which can be used for the palm oil-based biorefinery.

The biorefinery approach has been used for the valorization of coconut oil by Abderrahim Bouaid et al. [43]. Coconut oil, the main substrate for obtaining biodiesel by a process of transesterification, is a very costly raw material. The high cost of this substrate makes the process of obtaining biodiesel from coconut oil economically unviable. Hence, a process outlined in Fig. 1.25 has been proposed to get multiple products from coconut oil which would then make the process of conversion of coconut oil to biodiesel economically effective. Coconut oil contains 42-49% lauric acid. This lauric acid can be converted to methyl laurate, by a transesterification process. Methyl laurate forms the basis for the production of a number of products like lauryl sulfate (biodegradable surfactants), coconut estolide esters (LMWME’s) which serve as a base for biodegradable lubricants, and recently, biodiesel (methyl ester) a HMWME, which is emerging as a promising substitute for conventional fuels. The proposed biorefinery approach uses an integrated process for generation of HMWME (biodiesel) and LMWME (laurate and myristate methyl esters which can used as biolubricants and biosolvents). The lauric fraction has importance in the detergent industry as it is the preferred material for the manufacture of soaps and detergents due to its exceptional

cleansing properties. Under optimum conditions, a yield of 77.54% for HMWME’s and 20.63% for LMWME’s was obtained.

Gary Luo et al. [44] proposed a novel biorefinery concept for the production of biofuels (biodiesel and bioethanol) from rapeseed and straw. The process effluents from this process were further used for additional production of biofuels (biohy­drogen and biomethane). The overall bioenergy recovery was found to increase to 60% compared to an energy recovery of 20% in case of a conventional biodiesel conversion process.