Multi-aspect comparative analyses of two innovative methanol and power cogeneration systems from two different sources

Abstract

This study aims to develop two economically viable processes with high thermodynamic efficiency for the cogeneration of methanol and electricity from coke oven gas and blast furnace gas. In process A, syngas is obtained from coke oven gas reforming, and blast furnace gas, after providing the required heat for the reformer, is injected into the methanol synthesis reactor as a rich carbon source. In process B, in addition to coke oven gas and blast furnace gas, additional hydrogen produced by the proton exchange membrane electrolyzer is injected into the methanol reactor to enhance CO2 conversion. The performance of the proposed systems is evaluated using parameters like energy efficiency, exergy efficiency, net CO2 emission, and total production cost. Results show that energy efficiencies for processes A and B are 53.53% and 67.4%, and their exergy efficiencies are 23% and 25.12%, respectively. Moreover, environmental analysis demonstrates that process B has a net CO2 emission of −1.818 kgCO2/kgmethanol, while for process A, this parameter is relatively higher, and it is positive. From the economic viewpoint, it is concluded that process B is more feasible, and the total production cost of methanol decreases by 55.51% compared to process A.