Direct conversion of carbon dioxide to liquid fuels and synthetic natural gas using renewable power: Techno-economic analysis

The conceptual design of a base case power-to-liquids (PTL) process that converts CO₂ to liquid fuels and a hybrid PTL/power-to-gas (PTG) process that converts CO₂ to liquid fuels and high-calorie synthetic natural gas (SNG) was carried out by using an Aspen Plus simulator. Based on the established process models, we conducted a technical study to investigate the effects of recycle ratios on the process performance such as the energy efficiency and the net CO₂ reduction of the proposed hybrid PTL/PTG process, and compared it with the base case PTL process. After the technical study, an economic analysis was further implemented to evaluate the economic performance of the hybrid PTL/PTG and the base case PTL processes and to pursue the optimum process configuration of the proposed hybrid PTL/PTG process. According to the results of the technical study and economic analysis, it can be concluded that both the base case PTL process and the hybrid PTL/PTG process can be regarded as candidate technologies for the conversion of CO₂ to value-added liquid fuels and/or high-calorie SNG. Moreover, the hybrid PTL/PTG process seems to be more efficient and profitable in utilizing CO₂ because of its higher energy efficiency and net CO₂ reduction as well as lower CO₂ reduction cost in comparison with the base case PTL process.