Process Design of Mixed Flow Reactor for Lye-Catalysed Transesterification Reaction

Abstract

The design of a continuous transesterification process for biodiesel production was carried out using ASPEN HYSYS software. The feed consisted of castor oil and methanol in the ratio 1:6 with catalyst (lye) loading of 1 wt % of oil. A conversion of 99.97 % was achieved. The transesterification reaction took place at 60 oC and atmospheric pressure. The basis for the process design was 1 kmolhr -1 of castor oil feed which gave 1.107 m3hr -1 of biodiesel and 0.08 m3hr1 of glycerol. Based on the studies carried out, the process proved to be feasible with biodiesel purity of 99.7 % and methanol recovery of 99.71%. Glycerol was also obtained as a by-product with a purity of 89.09 %. The HYSYS process modelling tool generated heat and material balance data for the process as well as the sizing of the continuous stirred tank reactor and other equipment. The data obtained were used in the cost estimation of biodiesel production. The total production cost of biodiesel was set at $9,502,813.40 per annum (NGN 4,513,836,365) at the prevailing exchange rate of $1 to NGN475. The single greatest contributor to this value was the cost of the castor oil feedstock, which accounted for 84.2 % of the total estimated production cost. This is, however, on a high side therefore impairing the financial feasibility of the biodiesel production from castor oil.