Utilizing Carbon Dioxide For Methanol Production:System Design And Optimization

CO2 is the main anthropogenic greenhouse gas,and its emissions have increased significantly with the growing industry.The process of converting large amounts of CO2 from industrial flue gas into value-added products is a possible way to deal with climate change and high energy consumption.Due to the low energy efficiency of the traditional hydrogenation process from CO2 to methanol,the integration of new energy and traditional energy is not realized by means of multienergy complementation.In this work,the process flow simulation of the CO2 to methanol was carried out,and the process flow of CO2 direct hydrogenation to methanol and solar-wind energy electrolysis of water to hydrogen was designed and optimized.(1)The Aspen Plus V11 software was used for system design and parameter optimization,and a direct CO2 hydrogenation to methanol process was developed based on a consumption of 5000 t/a of CO2.The reaction unit was synthesized using a Cu/Zn/Al/Zr catalyst and the reaction conditions were optimized by refining the reaction kinetics of the catalyst in Aspen.The results showed that the optimum reaction temperature,pressure and space velocity of methanol preparation were 501K,50 bar and 5.9 m3/kgcat·h;the effective elemental C utilization rate was 99.82%;and the methanol yield of the process was 72.69%after cycling.(2)Combined with the 300000 tons of electrolytic manganese metal technical renovation project of Tianyuan Manganese Industry in Ningxia,the process of methanol production using 10,000 tons of CO2 per year was simulated.The direct hydrogenation of CO2 to methanol and the electrolysis of water to hydrogen by solar-wind energy were established,and the supporting photovoltaic power generation system was simulated and designed by TRNSYS 18.The results showed that the energy utilization efficiency of the process(34.78%)was higher than that of the baseline S2P process(11%),the full process yield of methanol(72.61%)was higher than the baseline S2P process(66%),natural gas to methanol(72%)and coal to methanol(37%).The annual profits will increase by 6.7102× 107 ＄,and reduce greenhouse gas emissions.