Comparative life cycle energy consumption, carbon emissions and economic costs of hydrogen production from coke oven gas and coal gasification

Abstract

Traditional hydrogen production is primarily based on coal gasification in China, and it faces severe challenges relating to its high energy consumption and carbon emissions. Coke oven gas-based hydrogen (COGH) promises to be a potential alternative route for producing coal gasification-based hydrogen (CGH) due to the large-scale coking industry in China. Therefore, it is imperative to understand which route is better. In this study, a life cycle model is developed to compare the energy consumption, carbon emissions and economic cost of the two routes. The model boundary covers all processes from raw material extraction to hydrogen production. Four allocation scenarios (viz. market value allocation, mass allocation, energy allocation and no allocation) are considered to address the burden allocation between various products involved in the coal coking process. Furthermore, the effects of variations in several key parameters on the performance of the two routes are investigated through a sensitivity analysis. The results show that COGH has better technical, environmental and economic performance than CGH. The energy consumption, carbon emissions, capital expenditure and operating expenditure of COGH are 34.6%, 36.7%, 27.4% and 8.7% lower than those of CGH, while the profit and internal rate of return of COGH are 1.35 and 2.33 times those of CGH. Aside from no allocation, market value allocation is most favourable for COGH in view of its reduced energy consumption and carbon emissions. Compared with CGH, COGH has much stronger economic competitiveness in the face of raw material price fluctuations. This alternative route has broad development prospects because of its excellent comprehensive performance and large-scale industrial base, while efficiency improvements and energy savings should always be considered. The results provide a comprehensive and valuable basis for comparing the strengths and weaknesses of the two routes and to help policymakers take measures to promote the development of the hydrogen production industry.