Mathematical modeling of proton-conducting electrochemical cells for ethylene production from ethane

The efficient conversion of ethane to ethylene in proton-conducting electrochemical cells (PCECs) is an emerging technology, garnering considerable research attention. However, the absence of modeling study concerning PCECs for ethylene production leads to limited fundamental and quantitative understandings of electrochemical/energy performance of the system. Aimed to fill this gap, an electrochemical model of PCECs is developed in this study. The electrochemical performance, Faraday efficiency, and energy performance of PCECs in the fuel cell mode and hydrogen pump mode are evaluated and compared. It is demonstrated that the decline of Faraday efficiency, caused by the current leakage within the electrolyte layer, is a problem in the fuel cell mode, rather than in the hydrogen pump mode. In addition, electric energy has a larger effect on the energy performance in the fuel cell mode than in the hydrogen pump mode. As a result of the combined effect of Faraday efficiency and electric energy, higher energy efficiency is achieved in the hydrogen pump mode. Moreover, introducing steam to the anode side is found to be beneficial for the conversion of ethane and the electrochemical performances of PCECs, mainly owing to the positive effect of humidity on the proton conductivity of electrolytes.