Thermal Modeling for High Temperature Electrolysis of Lithium Carbonate with Carbon Dioxide Sequestration

Abstract

This paper introduces a thermal modeling and simulation study for high-temperature electrolysis of molten lithium carbonate, an electrolyte used for decreasing the emission of CO2 during fuel combustion. The electrolytic cell is comprised of a crucible with hollow cylindrical partitions filled with molten lithium carbonate. Voltage is applied through the electrodes that are comprised of a cylindrical cathode surrounded by two cylindrical anodes. Hot CO2 is bubbled into the electrolyte and serves as an extra heat source in addition to replenishing the carbon deposited during electrolysis. If the electrolysis is carried out at thermoneutral potential, and thus the exothermic dissolution of CO2 is the only reaction that generates additional heat in the system. On the other hand, applyingoverpotentialwill generate additional heat and thus help mitigate radiation losses. We study the interplay of these various parameters by using COMSOL Multi-physics software to simulate the experimental setup. The captured CO2 rate of the electrolyte and the input temperature, as well as applying overpotential, will influence the results. Detailed results presented here can thus guide the experiment in choosing the suitable settings.