An integrated model for the technical and economic evaluation of an enzymatic biomass conversion process

Abstract A process simulation model was constructed, using the Lotus 123 spreadsheet, to evaluate the technical and economic feasibility of a lignocellulosic-to-ethanol bioconversion process. The major components of the process were: steam pretreatment, fractionation, enzyme production, enzymatic hydrolysis, ethanol fermentation of glucose and xylose, product recovery, and waste treatment. The model provided an estimation of the price of ethanol and evaluated the interdependence of process parameters and their effect on the production cost of ethanol. A case study of a plant processing 500 tonnes of aspenwood per day showed that the parameters which had the most significant impact on the price of ethanol were: the cost of wood, cost of enzymes, efficiency of cellulose hydrolysis, ethanol yield from xylose, efficiency of the fractionation process, and the selling price of the lignin by-product. The benefits of developing a model included the identification of areas for technical improvement, reduced time and cost for scale up and pilot testing.