The intermittence and site-dependence of renewables requires the efficient systems to storage the surplus wind/solar electricity. Substitute nature gas (SNG) is a promising energy carrier which facilitates existing pipeline transportation. This work proposed a novel efficient SNG production system, in which the high temperature electrolysis combined with oxygen/steam biomass gasification is adopted. In this proposed system, the O2 produced by electrolyzer is sent to the gasifier directly and the air separation can be eliminated. Besides, through the coexistence methanation process, the conventional water gas shift process and CO2 capture consumption will be avoided. The electrochemical model of SOEC is established and the whole SNG production system is simulated by Aspen plus. Parametric and energy/exergy analyses are conducted and the results shown that the thermal efficiency of the novel plant can reach 77.4%, which is 15 percentage points higher than the traditional SNG production pathways. This work provide a new method to realize high energy conversion efficiency and reduce the wind/solar energy curtailment.
Keywords SNG production, high temperature electrolysis, steam/oxygen biomass gasification, thermodynamic analyses