Catalysis Today, Vol.237, 13-17, 2014
Biofuel synthesis in a capillary fluidized bed
Hydrotalcite, MgO, CaO and zeolites transesterify canola oil in the gas phase at temperatures above 300 degrees C and atmospheric pressure. Syringe pumps metered oil and alcohol through a 1/8" tube to the bottom of a 7 mm "capillary"-fluidized bed. Argon gas entered the annular region of the bed through a sintered glass frit as supplemental fluidizing gas. Oil conversion was complete with excess methanol in the feed. Contact times were less than 0.3 s and the weight-hourly space velocity was on the order of 15 h(-1) (0.15 ml min(-1) oil feed rate with 0.5 g of catalyst). As the catalyst deactivates, the oil condenses and the fluidized bed collapses. The zeolite deactivated within 2 min; the hydrotalcite could operate for several minutes; the CaO and MgO operated without interruption for well over 20 min. Periodic oxidation of the catalyst maintained catalyst activity. (C) 2014 Elsevier B.V. All rights reserved.