Biodiesel from Different Oil Using Fixed-Bed and Plug Flow Reactor

In this study, a pilot scale of 100 t/year biodiesel production system, mainly consisting of a fixed-bed and a down-stream plug-flow reactor, was setup to test the different feedstock oil, especially a kind of high acidified oil, trap grease, for their feasibility of being biodiesel feedstock in China. The tested oil includes three kinds of typical oil from Guangdong Province, China: rapeseed oil, Chinese wood oil and trap grease. Meanwhile the optimum residence time for a plug flow reactor to perform transesterification reaction was investigated in this study. At the condition of temperature being 65℃, methanol/oil molar ratio being 6:1 and KOH load being 1.2 wt% of oil, it was found to be 19 min. A kind of an ion exchange resin filled in the fixed bed reactor was used as the esterification catalyst for the pretreating of high-acidified oil. For the fresh catalyst, the acid value of trap grease could be reduced from 114 mg KOH/g to about 2 mg KOH/g after 13 h at temperature of 75℃, catalyst load of 15 wt% of oil, methanol addition being 20 wt % of oil. The lifetime test for the catalyst indicated that its life is over 30 days. The quality of biodiesel derived from three feedstock oils is compared with newly published China BD100 standard of GB/T20828-2007. The comparison results reveals that the biodiesel generated through this system could meet China BD100 standard well. It indicates that the designed process in this system has a good adaptability for different kinds of oil.