Green hydrogen coupling with CO2 utilization of coal-to-methanol for high methanol productivity and low CO2 emission

The conventional coal-to-methanol (CTM) process suffers from large CO2 emission. The additional hydrogen supplement to the CTM process can effectively improve the carbon utilization efficiency. However, the CO2 emission intensity and cost of existing hydrogen production technologies based on fossil resources are extremely high. This paper proposes a green hydrogen (GH) production integrated with CO2 utilization of the CTM process. The new process is called GH-CTM process, which can achieve intensive material coupling, improve carbon efficiency, and increase methanol productivity. Process modeling, parameters optimization, and simulation results showed that the energy efficiency, CO2 emission, and methanol output of the proposed process were 10.52% higher, 85.64% lower, and 124.67% higher than those of the conventional CTM process, respectively; moreover, the production cost of the proposed process was 23.95% lower than that of the CTM process, and the payback period of investment (2.8 years) was lower than that of the CTM process (7.2 years). In addition, the internal rate of return of the proposed process was increased by 47.37% compared with that of traditional CTM process. The proposed process provides a promising method for the introduction of green hydrogen to realize CO2 utilization and the sustainable conversion of coal to chemicals. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study proposes the GH-CTM process, which integrates green hydrogen production with CO2 utilization to improve energy efficiency, reduce CO2 emissions, increase methanol output, and lower production costs and payback period.