The production of biodiesel by the transesterification reaction of glycerides (rapeseed oil) with methanol, in a continuous-flow fixed-bed catalytic reactor was explored. Based on data in the literature, lanthanum oxide and strontium oxide (SrO) catalyst systems were selected for this work. In preliminary experiments in a batch reactor (300 cm3; with 160 cm3 of oil), ceramic monoliths (61 cells cm-2; hydraulic cell diameter = 1.1 mm) acted as catalyst supports. At the conditions tested (T= 120ºC; P = 8 bar(g); molar ratio methanol:oil = 6:1), the monoliths coated with SrO (19.6 wt% SrO), were found to be sufficiently active to proceed to the continuous flow fixed-bed trials. A study of the solubility of methanol in oil, showed that in a pressurized autoclave at 100ºC, the methanol dissolved at a 6:1 molar ratio, and at 120ºC this increased up to 9:1, providing useful information for the design of a continuous flow reactor.The SrO slurry coated monolith was then tested in a single-tube fixed-bed reactor (i.d. = 6.2 mm; L = 200 mm). In experiments at a 7:1 molar ratio of methanol:oil, at T = 195 ºC, and P = 20 bar(g), although catalytic activity was cyclic in nature, it was maintained over a 300 h period (not continuous) of operation. This led to the performance of experiments in a multi-tubular reactor, which consisted of 5 tubes, connected in series (each tube with an i.d. = 22 mm; L = 550 mm). It was now possible to perform experiments with a longer overall length of monolith sections, and to take samples between each tube. Experiments were performed with a monolith bed length of 2300 mm and a molar ratio of methanol:oil = 7:1 (T = 150ºC, P = 15 bar(g)), with overall conversions ranging from 20 to 50%.
|Date of Award||1 Jul 2014|
|Sponsors||Engineering and Physical Sciences Research Council|
|Supervisor||Stan Kolaczkowski (Supervisor), Matthew Davidson (Supervisor) & Serpil Awdry (Supervisor)|