Biodiesel from seed oils such as rapeseed and mustard has attracted increasing interests and has been shown to be the best substitute for fossil-based fuels due to its environmental advantages and renewable resource availability. Seed oils of rapeseed, canola, and yellow mustard have certain advantages for biodiesel production over other vegetable oils, among them are better cold-flow properties. There is a great demand for the commercialization of biodiesel production, which in turn calls for a technically and economically sound reactor technology. Reactive distillation (RD) is a chemical unit operation in which chemical reactions and separations occur simultaneously in one unit. It is an effective alternative to the classical combination of reactor and separation units especially when involving reversible or consecutive chemical reactions. Packed columns are preferred because the packing can be the catalyst for chemical reactions. The significant advantages of the RD over the conventional sequential process are high chemical conversion rate and low capital and operational cost. The operation of an RD process can be very complicated and the performance of a reactive distillation column is influenced by several parameters, e.g. size of reactive and separation zones, reflux ratio, feed rate and location, etc.
The ultimate goal of the proposed research is to explore a technically and economically sound reactor technology for biodiesel production. The reactive distillation technique will be applied to the transesterification of seed oils of rapeseed, canola and yellow mustard. The hypothesis is that by employing the RD technique, biodiesel preparation and product concentration can be accomplished in one single unit. The alcohol to seed oil ratio is reduced to its theoretical stoichiometric ratio (1:3 molar) in the feeding stream, but a high alcohol to oil ratio, which ensures the complete conversion of the reactants to biodiesel, is achieved in the reaction zone by recycling a small quantity of alcohol in the reaction zone. Use of excessive alcohol can be eliminated and the recovery of alcohol can be integrated within one unit that reduces capital and operating costs.