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 CO 2 emission. The additional hydrogen supplement to the CTM process can effectively improve the carbon utilization efficiency. However, the CO 2 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 CO 2 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, CO 2 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 CO 2 utilization and the sustainable conversion of coal to chemicals. • Green hydrogen integrated with CO 2 utilization of CTM process is proposed. • Methanol production is increased by 124.67% through CO 2 utilization. • Green hydrogen supplement makes 85.64% reduction of CO 2 emission and 10.52% increase of energy efficiency. • Production cost is decreased by 23.95% resulting of 47.37% increase of internal rate of return. • Introduction of green hydrogen realizes CO 2 utilization and clean conversion of coal.