Integrated Process And Techno-economic Evaluation For Producing Glycolic Acid From CO₂ Capture Coupling Green Hydrogen

Liquid sunlight methanol synthesis can not only store renewable energy in liquid fuel methanol,but also consider carbon dioxide emission reduction and economic development,which is a practical technical route and powerful means to achieve the carbon peaking and carbon neutrality goals.Extending the downstream product chain of methanol and developing the biodegradable plastic polyglycolic acid,which is widely studied at present,can realize the increase of carbon value,get rid of the inherent defects of renewable energy such as intermittancy,volatility and randomness,and is also an important means to promote the large-scale development of new energy.In this study,a process route of producing glycolic acid from carbon dioxide through CO2 hydrogenation to methanol,methanol oxidation to formaldehyde and formaldehyde carbonylation is proposed,starting from CO2 capture.This study provides a theoretical foundation and direction for carbon capture,conversion,and utilization in the context of carbon peaking and carbon neutrality goals.This study also provides development ideas for exploring coupling paths between conventional and novel energy sources.In view of the considerable energy consumption of the traditional process of CO2 capture by chemical absorption,the present study utilizes the phase change absorbent of ethanolamine(MEA)/n-propanol/water to facilitate CO2 capture from flue gas.The CO2 capture process is modeled and analyzed using Aspen Plus,while the phase separation process is performed using a separator.The simulation results show that the total regeneration energy is reduced to 2.40 GJ/t-CO2,which is 39.85%lower than the baseline condition with 30 wt%MEA as solvent.In the traditional CO2 hydrogenation process to methanol,the loss of CO2 and H2 is caused by the release of net CO,which leads to the reduction of the utilization rate of hydrocarbon elements.According to the analysis results,a specially designed cycle process is proposed to improve the conversion rate of CO2 and selectivity of methanol.Under the condition of total recycling,the CO flow difference can be close to zero,and the utilization rate of carbon element is more than 99.70%.The generated reaction heat can offset part of the hot steam,after the use of double-tower double-effect rectification to reduce the heat utility,only 13.70 MW of cooling water.The whole process of glycolic acid synthesis by CO2 trapping coupled to green hydrogen was studied by rigorous steady-state modeling and simulation for four units,and the process parameters were analyzed and optimized for each unit.The process was evaluated from the perspectives of carbon utilization,energy analysis and integration,CO2 emissions,and technical economy.Through global thermal integration,it can reduce the consumption of public works,reduce production costs,and increase the competitiveness of the process.The results show that the optimized heat exchange network is 1102.89 MW for cold utilities,409.67 MW for hot utilities,and 45.98 MW for power consumption.After global thermal integration,the carbon utilization rate of the process is 82.5%,the total energy consumption is reduced by 27.4%,and the total production cost is 834.75 $/t-GA.