Economic assessment of batch biodiesel production processes using homogeneous and heterogeneous alkali catalysts.

An economic feasibility study on four batch processes for the production of biodiesel ranging from 1452 tonnes/year (5000 l/day) to 14,520 tonnes/year (50,000 l/day) is conducted. The four processes assessed are the (1) KOH-W process, characterized by a homogeneous KOH catalyst and hot water purification process; (2) KOH-D process, characterized by a homogeneous KOH catalyst and vacuum FAME distillation process; (3) CaO-W process, characterized by a heterogeneous CaO catalyst and hot water purification process; and (4) CaO-D process, characterized by a heterogeneous CaO catalyst and vacuum FAME distillation process. The costs of the waste cooking oil, fixed costs, and manufacturing costs for producing 7260 tonnes/year (25,000 l/day) of biodiesel by means of the four processes are estimated to be $248-256, $194-232, and $584-641 per tonne of biodiesel, respectively. Among the four processes, the manufacturing costs involved in the CaO-W process are the lowest, in the range from 1452 tonnes/year to 14,520 tonnes/year.