Abstract:

The burning of large amounts of fossil fuels has led to a rise in greenhouse gas emissions and global warming. The world has proposed a global agreement to reduce CO₂ emissions, and China has proposed the goal of “carbon peaking and carbon neutrality”. CO₂ capture and conversion to liquid fuels and chemicals are one of the effective carbon reduction measures under the carbon peaking and carbon neutrality targets, which not only can realize the resource utilization of CO₂, but also alleviate the national energy security problem. In this paper, we analyze the CO₂ to methanol process coupling green hydrogen, which is based on four different CO₂ capture technologies, taking CO₂ capture from flue gas of coal-fired power generation and CO₂ to methanol as the research objects. Rigorous steady-state modeling and simulation of the CO₂-to-methanol process with four different CO₂ capture technologies are carried out, and compare the technical-economic performance of the CO₂-to-methanol process under different cases of CO₂ capture technologies. The results show that the energy consumption per unit of methanol is 7.81, 5.48, 5.91 and 4.66 GJ/t CH₃OH for the MEA case, PCS case, DMC case and GMS case, respectively. And the GMS case has the lowest energy consumption, followed by the PCS case, but with the development of more efficient phase change solvents, the energy consumption will be reduced to 2.29—2.58 GJ/ t CH₃OH for the PCS case. The total production costs of the four cases are 4314, 4204, 4279 and 4367 CNY/ t CH₃OH, respectively, and the PCS case has the lowest cost and is more economically competitive. The comprehensive analysis shows that the PCS case has the best performance and can be used as the best carbon capture technology for coal-fired power plants, providing directions for efficient CO₂ synthesis of fuel chemicals to alleviate fossil fuel shortage and environmental pollution problems.

Key words: CO₂ capture, CO₂-to-methanol, simulation, process systems, techno-economic analysis

摘要：

大量的化石燃料燃烧导致温室气体排放增加，全球气候变暖。世界各国以全球协约的方式减排CO₂，我国也由此提出“碳达峰·碳中和”目标。CO₂捕集以及转化制液体燃料和化学品是双碳目标下行之有效的碳减排措施之一，不仅可以实现CO₂的资源化利用，同时也缓解了国家能源安全问题。本文以燃煤电厂烟气CO₂捕集和CO₂合成甲醇为研究对象，分析了基于四种不同CO₂捕集技术的CO₂耦合绿氢制甲醇工艺。对四种不同CO₂捕集技术的CO₂制甲醇工艺进行了严格的稳态建模和模拟，分析和比较了不同CO₂捕集技术情景下的CO₂制甲醇工艺的技术和经济性能。结果表明，MEA、PCS、DMC和GMS情景的单位甲醇能耗分别是7.81、5.48、5.91和4.66 GJ/ t CH₃OH，GMS情景的单位能耗最低，其次是PCS情景，但随着更高效相变吸收剂的开发，PCS情景的单位甲醇产品的能耗将降低至2.29~2.58 GJ/t CH₃OH。四种情景的总生产成本分别是4314、4204、4279和4367 CNY/ t CH₃OH，PCS情景的成本最低，更具有经济优势。综合分析表明PCS情景的性能表现最好，为可用于燃煤电厂最佳的碳捕集技术，为CO₂高效合成燃料化学品提供方向，缓解化石燃料短缺和环境污染问题。

关键词: CO₂捕集, CO₂制甲醇, 模拟, 过程系统, 技术-经济分析