Biofuels rapeseed methyl ester

Rapeseed methyl ester (RME) is another alternative biofuel that can be used in diesel engines. RME has the advantages that it is renewable compared to diesel, non-toxic and less flammable compared with many other fuels, like ethanol. RME has the same cetane number, viscosity and density as diesel, contains no aromatic compounds and is biologically degradable with minor contamination in soil. RME can be produced from vegetable oils, but is mostly produced from rapeseed oil by pressing of the seeds or by extraction. Up to 3 tons of rapeseed can be produced from one hectare. The fatty acids in rapeseed oil are mostly oleic acid, linoleic acid and linolenic acid. The oil is pressed from the plant and after some purification allowed to react with methanol in the presence of potassium hydroxide as a catalyst, to produce a methyl ester, see Figure 6.6. 

Bioethanol (mainly from sucrose and starchy crops) and biodiesel production (via transesterihcation of triglycerides) are the main first-generation biofuels that are currently produced on industrial scale. Biodiesel is produced by transesterihcation of triacylglycerols with short-chain alcohols (mainly methanol or ethanol) to produce monoalkyl esters, namely fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs). The worldwide production of biodiesel is mainly dependent on the utilization of waste oils, animal fats, and oilseeds such as rapeseed, sunflower, and soybeans. The recent food crisis has shown that research should focus on the development of second-generation biofuels generated from lignocellulosic raw materials and industrial waste streams (eg, food industry wastes). 

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