Process Simulation,Economic Analysis And Life Cycle Assessment Of Coal Gasification With Syngas Adjustment For Methanol Production

Coal is one of major primary energy source in China.Coal gasification enables the conversion from coal to a huge chemical industry and secondary energy supplies（such as hydrogen）in the economic and clean way,which is so-called the clean coal chemical industry.This is especially true in China.This thesis focuses on the technological innovation of coal gasification,which is the coal chemical looping gasification technology,toward the production of clean energy and chemical raw material of hydrogen and methanol.This study compare aspects of technology structure,economic and environment impacts to the the conventional coal gasification technology.Aspen plus V8.4 software and life cycle Simapro7.1 software were used to simulate and analyze the selected technical process and the process technology economy and life cycle.The life cycle mainly focused on CO₂emissions.The technical and economic analysis mainly focuses on the total investment and product investment in hydrogen and methanol production.the main conclusions are as follows:1.In the conventional coal gasification process,the optimal operation conditions toward the maximization of the methanol output were:the water-to-coal ratio was 0.45（kg/kg）,the oxygen to coal ratio is 0.4（kg/kg）,and the gasification temperature of the gasification is about 1200℃.In terms of the operational pressure,its impact on the syngas quality was found to be ignorable,and thus.2.In the coal chemical looping gasification process,the optimal operation conditions toward the maximization of the methanol output were:the ratio of coal to oxygen carrier was0.18（kg/kg）,and the air-to-coal ratio was 4.3（kg/kg）,and The operational pressure was 3MPa.Yo satisfy the self-heat supply among different reactors,the air temperature was found to be1250℃.3.According to the life cycle assessment,the CO₂ emission in the conventional coal gasification to methanol process was as high as 0.56（kg/kg）,which could be controlled as low as 0.274（kg/kg）in the coal chemical looping gasification combined with chemical looping hydrogen production.4.The chemical economic analysis,addressing the investment and production situation of the two technical routes from coal-to-methanol indicated that,on the basis of one ton methanol,the fixed investment of methanol was 143.5RMB/t/y and methanol product cost of1747.6RMB/t/y in the conventional coal gasification process could be largely dropped to138.2RMB/t/y and 1515.8RMB/t/y,respectively.Therefore,the technical routine via the coal chemical looping conversion can greatly improve the economic and environmental aspects of coal gasification process.