COMPUTER-AIDED ELECTROCHEMICAL PROCESS DESIGN - SIMULATION AND ECONOMIC-ANALYSIS OF AN ELECTROCATALYTIC SOYBEAN OIL HYDROGENATION PLANT

The process flowsheet for a soybean oil electrohydrogenation plant has been devised and heat and mass balance calculations on unit operation s equipment were performed using a commercially available process simu lation software package (PRO/II from Simulation Sciences, Inc.). The d esign and anticipated performance (current efficiency and power requir ements) of the electrochemical flow cells were based on a laboratory-s cale radial-flow-through Raney nickel powder electrocatalytic hydrogen ation reactor. A semiempirical porous electrode model, that reproduced laboratory-scale reactor data, was incorporated into the PRO/II softw are as a unit operations subroutine module. Operation of a 3.0 x 10(6) kg y(-1) electrochemical plant was simulated on a computer for differ ent soybean oil/electrolyte feeds and reactor current densities. Based on the PRO/II results, an economic analysis of the process, including capital, installation and operating costs of all equipment was carrie d out. The lowest total production cost for a brush hydrogenation oil product (20% reduction in the number of double bonds) was obtained at a current density of 15 mA cm(-2) and a feed composition of 10 wt:vol % soybean oil in solvent/supporting electrolyte (US$ 0.13 kg(-1) for a n assumed five year straight line depreciation of capital equipment). This cost was higher than that for a comparable-size chemical catalyti c soybean oil hydrogenation plant (US$ 0.019 kg(-1)). When the cost of the soybean oil starting material (US$ 0.68 kg(-1)) was factored into the economic analysis, the production plus raw material cost of the e lectrocatalytic process was only 16% greater than that for the chemica l catalytic plant. The production cost for the electrosynthesized hydr o-oil product may be tolerable because the oil has a high nutritional value (a lower trans isomers content) which may command a higher selli ng price.