A membrane reactor process for the production of biodiesel

Peigang Cao, Université D'Ottawa / University Of Ottawa, Université D'Ottawa / University Of Ottawa
Bench and pilot scale membrane reactors were designed and assembled to carry out the transesterification of different lipids with methanol. The membrane reactors integrate many procedures and reach several process integration objectives such as combining reaction and separation in a single unit, continuous mixing of raw materials, maintaining high mass transfer between the immiscible phases and maintaining two phases during the reaction. Several factors affecting the biodiesel production
more » ... l production process and the biodiesel purity such as membrane pore size, volume ratio of feedstocks, recycling of the polar phase, catalyst (NaOH) concentration, and feedstock type and quality were investigated. Thus, a series of experiments using canola, palm, soybean and waste oils were performed at various alcohols to oil ratios, recycling proportions, catalyst (NaOH) concentrations, and residence times. Carbon membranes of different pore sizes (namely, 0.05, 0.2, 0.5 and 1.4 micron) were shown to retain the unreacted lipid feedstock in the reactor, which indicated that the oil droplets present in the reactor were larger than all the pore sizes; no triglycerides were found in the permeate. The effects of initial methanol/canola oil loading were also studied in semi-continuous mode. Permeate was observed at the 0.38, 0.47, and 0.64 initial methanol volume fractions (&phis1) whereas it was not observed at &phis 1 = 0.29, which indicated that initial volume fractions of methanol up to 0.38 could be treated in the membrane reactor. A semi-empirical model was developed and validated as a predictive equation to determine phase inversion in the reactor. The membrane reactor produces a permeate stream which readily phase separates at room temperature into a FAME (fatty acid methyl ester)-rich non-polar phase and a methanol- and glycerol-rich polar phase. To decrease the overall methanol:oil molar ratio in the reaction system, the polar phase was recycled. Three recycle ratios were tested: 100, 75 and 50%, at the same residence time and [...]
doi:10.20381/ruor-19789 fatcat:rlpna4ajanen3n2jlkydpiwgcm