Environmental impact and techno-economic analysis of the coal gasification process with/without CO2 capture

Abstract

Coal gasification, the technology for high-efficient utilization of coal, has been widely used in China. However, it suffers from high CO2 emissions problem due to the carbon-rich character of coal. To reduce CO2 emissions, different CO2 capture technologies are developed and integrated into the coal gasification based processes. However, involving CO2 capture would result in energetic and economic penalty. This paper analyses three cases of coal gasification processes from environmental, technical, and economical points of view. These processes are (1) a conventional coal gasification process; (2) a coal gasification process with CO2 capture and sequestration, in which CO2 is stored by mineral sequestration; (3) a coal gasification process with CO2 capture and utilization, in which CO2 is reused to produce syngas. The results show that the coal gasification process with CO2 capture and sequestration has advantage only in environmental aspect compared to the conventional process. The process with CO2 capture and utilization has advantages in both technical and environmental aspects while disadvantage in economic aspect. However, if the carbon tax higher than 15 USD/t CO2 is introduced, this disadvantage will be negligible.