Optimal Design of Synthesis Gas Production Process with Recycled Carbon Dioxide Utilization

Many countries are trying to reduce their primary energy demand and greenhouse gas (such as carbon dioxide (CO 2 )) emissions. There has been much research on CO 2 utilization to reduce CO 2 emission and increase economic efficiency in industries. In this paper, an integrated optimization strategy of an industrial synthesis gas production plant with additional CO 2 recycling processes using carbon dioxide as a reactant is presented. The CO 2 recycling process allows three different kinds of alternative synthesis gas reaction processes in parallel: steam reforming, dry methane reforming, and reverse water−gas shift reaction. The strategy is based on the integrated superstructure optimization that assists the formulation of the optimal process design problem such that mixed integer programming can be derived. The mathematical programming problem which has flexibility in selecting different synthesis gas reaction processes is used to find the optimal configuration of the process. The industrial synthesis gas plant case studies have been applied to present the optimization strategy. With the optimum configuration, the annualized profit increased by 14% and CO 2 emission decreased by 31% from the base case to the optimal structure. Three other extensions to the optimal design were evaluated for the case studies.