School of Chemical Engineering,Sichuan University
Sichuan Development EnvironmentalScience and Technology Research Institute Co.,Ltd

为应对全球气候变暖等环境问题,碳捕集、利用和封存(CCUS)技术得到了越来越多的关注。CO2加氢制甲醇既可以实现CO2资源化利用,也可实现可再生能源的化学储存,是一种重要的CCUS技术。为探索优化CO2加氢制甲醇的工艺,在固定床反应器中测试了商用Cu-ZnO/Al2O3催化剂在CO2加氢制甲醇过程中的催化性能。探究了催化剂在448.15~543.15K,1~3MPa,H2、CO2物质的量比3~9的催化效果。结果表明,CO2转化率随反应温度升高而增加;甲醇选择性主要受温度和氢碳物质的量比影响:温度越高甲醇选择性越低,氢碳物质的量比越大甲醇选择性越高;压力升高对CO2转化率和甲醇选择性均有促进作用。以甲酸盐加氢步骤为反应的速率控制步骤,在LHHW动力学理论基础上推导建立了该催化剂用于CO2加氢制甲醇的反应动力学模型,在MATLAB中构建模型优化函数求解模型参数,获得反应动力学方程。2个反应活化能分别为42.4和122.1kJ/mol。在AspenPlus软件中建立CO2加氢制甲醇循环工艺,并通过增加流股间换热对循环工艺进行能耗优化。通过一个管壳式换热器将反应器出口气体热量回收用于原料气的预热,使预热过程能耗降低86.2%。同时对闪蒸分离温度和原料气预热温度进行灵敏度分析,最终选择闪蒸分离温度323.15K,原料气预热温度498.15K。工艺产品为摩尔纯度>99.5%的精制甲醇,甲醇回收率>99%,工艺最佳甲醇生产能耗4.84GJ/t。

Carbon capture, utilization and storage (CCUS) technology has received increasing attention in order to cope with environmentalproblems such as global warming. CO2 hydrogenation to methanol is an important CCUS technology, realizing both CO2 resource utilizationand chemical storage of renewable energy. In order to explore and optimize the process of CO2 hydrogenation to methanol, the catalytic performance of commercial Cu - ZnO/ Al2 O3 catalyst in the process of CO2 hydrogenation to methanol was tested in a fixed bed reactor.The catalytic effects of the catalyst at 448.15-543.15 K, 1-3 MPa, and 3-9 molar ratio of H2 and CO2 were investigated. The resultsshow that the CO2 conversion rate increases with the increase of reaction temperature. Methanol selectivity is mainly affected by temperature and hydrogen/ carbon molar ratio: the higher the temperature is, the lower the methanol selectivity is, and the higher thehydrogen/ carbon molar ratio is, the higher the methanol selectivity is. Both CO2 conversion and methanol selectivity are enhanced by increasing pressure. Taking formate hydrogenation step as the rate control step of the reaction, the reaction kinetic model of the catalyst usedin the process of CO2 hydrogenation to methanol was derived and established on the basis of LHHW kinetic theory. The model optimizationfunction was constructed in MATLAB to solve the model parameters, and the reaction kinetic equation was obtained. The activation energies of the two reactions are 42.4 and 122.1 kJ/ mol, respectively. The recycling process of CO2 hydrogenation to methanol was establishedin Aspen Plus software, and the energy consumption of the recycling process was optimized by increasing the heat transfer betweenstreams. The heat of the reactor outlet gas was recovered by a shell and tube heat exchanger for the preheating of the feedstock gas, whichreduced the energy consumption of the preheating process by 86.2%. At the same time, the sensitivity analysis of flash separation temperature and raw material gas preheating temperature was carried out, and the final choice of flash separation temperature was 323.15K,raw material gas preheating temperature was 498.15K. The process product is refined methanol with molar purity above 99.5% and methanol recovery >99%. The optimal methanol production energy consumption is 4.84 GJ/ t.

国家重点研发计划资助项目(2022YFB4102100)

邱浩书,宋磊,杨秋林,等.CO2加氢制甲醇反应动力学及工艺能耗优化[J].洁净煤技术,2024,30(4):102-110.

QIU Haoshu,SONG Lei,YANG Qiulin,et al.Kinetics and process flow simulation and optimization of CO2 hydrogenationto methanol[J].Clean Coal Technology,2024,30(4):102-110.