This paper studied the simulation of methanol synthesis from CO2 and green hydrogen,and proposed an indicator of the energy storage density of CO2.Then influences of multiple variables on the performance indicators were analyzed.The results show that the systematic energy efficiency and energetic yield of methanol increase with the increase in the electrolysis efficiency,per pass CO2 conversion rate,electrolysis pressure,and initial CO2 pressure.However,these indicators decrease with the increase in the methanol synthesis pressure.The variations of the energy storage density of CO2 with these variables are opposite to the systematic energy efficiency and energetic yield.The electrolysis efficiency and per pass CO2 conversion rate are the sensitive and key variables of this process.Under the optimal conditions,the systematic energy efficiencies based on the higher and lower heating values are 68.0％and 59.6％,respectively,the energy storage density of CO2 is 6.07 kW·h/kg,and the energetic yield of methanol is 0.108 kg/(kW·h),indicating the power-to-methanol system using CO2 as feedstock is unsatisfactory in term of systematic energy efficiency,but has significant advantage in the energy storage density.
关键词
电解水/CO2利用/甲醇/流程模拟/系统能效/储能密度
Key words
water electrolysis/CO2 utilization/methanol/process simulation/systematic energy efficiency/density of energy storage
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