John D. Ingham

Conversion of bioprocess ethanol to industrial chemical products: applications of process models for energy-economic assessments

Ethanol is commercially produced by bioconversion and by hydration of ethylene. Bioconversion has the significant advantage that utilization of nonrenewable petroleum resources is minimized. Advanced bioprocesses for aqueous ethanol can also be integrated with downstream systems for energy-efficient conversion to added-value chemicals, such as esters or other ethylene or ethanol derivatives. Since the energy-intensive step involving azeotrope dehydration is eliminated, net process energy requirements can be less than for production of anhydrous ethanol. Energy-economic assessments of a potential esterification process are described, where ethanol vapor in the presence of water from a bioreactor is catalytically converted to ethyl acetate. A commercial ASPEN process simulation program was used, and results were compared with an assessment based on a JPL computer model. Detailed evaluations of the sensitivity of cost of production to factors, such as material costs and annual production rates, were also completed.