Optimal Design and Energy-Saving Investigation of the Triple CO2 Feeds for Methanol Production System by Combining Steam and Dry Methane Reforming

The process of synthesizing syngas with the triple CO2 feeds is proposed to achieve an efficient use of CO2 that mitigates climate warming. Also, the amount of CO2 added in three locations as the variables of the process is optimized based on the CO2 conversion rate and the energy consumption per unit product (ECP) output flow rate by the genetic algorithm. The performances of the triple CO2 feeds in the methanol synthesis process had been evaluated by comparing with the traditional methanol production processes. To further reduce energy consumption, the irreversibility of each component and the locations of the inefficiency in the overall selected production process are studied on the basis of the exergy analysis. Pinch analysis is further used to find the optimal matching scheme. Compared with those of the proposed process, the energy consumption and the total exergy loss of the heat-integrated process are significantly reduced by 33.1 and 6.65%, respectively. Besides, the overall total annual cost is reduced by 10.1% and the cost of utilities is saved by 36.4%, which results in energy-saving.