Dynamic electro-thermal modeling of co-electrolysis of steam and carbon dioxide in a tubular solid oxide electrolysis cell

摘要

SOEC (Solid oxide electrolysis cell) has great potential to store unstable renewable energy in form of steady chemical energy. For this application, transient behavior in variable working condition is crucial. A 2D (two-dimensional) dynamic model was developed to predict the dynamic response of H2O/CO2 co-electrolysis in TSOEC (tubular solid oxide electrolysis cell). The dynamic model comprehensively considered the macroscopic fluid flow, microscopic diffusion, heat transfer and electrochemical/chemical reactions in the TSOEC. In this paper, the TNV (thermal neutral voltage) of TSOEC was specifically defined and calculated. The time constants of charge/mass/heat transport processes were evaluated. Further, the responses of current, gas concentrations, temperature, efficiency, conversions to electricity/gas flow/temperature step inputs were respectively studied. Through the study, appropriate transient operations were designed to improve efficiency and conversions. (C) 2015 Elsevier Ltd. All rights reserved.