Techno-economic analysis of methanol production from joint feedstock of coke oven gas and basic oxygen furnace gas from steel-making

Abstract

This paper presents a study of the techno-economic analysis of producing methanol (MeOH) from steel mill off-gases, especially coke oven gas and basic oxygen furnace gas. The mixed off-gases produce syngas with appropriate H2/CO ratio and are converted to MeOH. A detailed kinetic model over a commercial catalyst Cu/ZnO/Al2O3 is applied for MeOH synthesis reaction. Four process designs were analyzed; they are combinations of two syngas compositions and the presence or absence of an interim MeOH-separation unit. When production rate was 22.2–28.3 t MeOH h−1, the unreacted purged gas could be used to generate electricity or can be sold as a fuel. The energy efficiency was in the range of 54.6–55.9%, considering both MeOH and electricity as an energy output. A heat-exchanger network is designed to minimize energy usage in the process. We analyzed the proposed process techno-economically and calculated a minimum selling price. The best case gives $0.57 kg−1 which is slightly higher than the recent market price, although a sensitivity analysis suggests that the price can be decreased in some cases. This study can be a basis for further research on this process.