Multi-objective Optimization of Co-processing of Bio-oil and Vacuum Gas Oil: a Survey of Gasoline Selling Price and Bio-oil Co-processing Ratio

Abstract

The prices of the bio-diesel and bio-gasoline are generally higher than those of petroleum based fuels. The co-processing of bio-oil and vacuum gas oil in a fluid catalytic cracker has been proposed to utilize the existing refinery infrastructures and decrease the prices of bio-fuels. According to our previous study, the techno-economic analysis of the co-processing process, there is a contradiction between the minimum gasoline selling price and bio-oil co-processing ratio. In this work, the relations between the two factors (objectives) are investigated via a multi-objective optimization. Two co-processing scenarios, fast pyrolysis scenario using fast pyrolysis make bio-oil and catalytic pyrolysis scenario adopting catalytic pyrolysis produce bio-oil, are proposed to obtain the trade-off solution between the two objectives using the evaluation function method. The minimum gasoline selling price is approximately $3.1/gal if 20% bio-oil is co-processed for the two scenarios. The price is only about $1.9/gal if the bio-oil ratio is 1%. The trade-off solution between the two objectives is strongly depended on the weight factor. Therefore, the relation and the compromise between the bio-oil coprocessing ratio and the minimum selling price should be considered and determined before the co-processing technology industrializes.