Industrial Perspective of Electrified Ethylene Production via Membrane-Assisted Nonoxidative Dehydrogenation of Ethane

The potential of applying ceramic proton-conducting electrolysis cell (PCEC) membranes in ethylene production processes was explored in this work. To this end, the techno-economics of a PCEC-assisted ethane dehydrogenation process were compared against the conventional ethane steam cracking (SC) process. The PCEC process required four to five times more electricity than the SC process. Consequently, fully renewable electricity needed to be utilized in the PCEC process to outcompete conventional SC in terms of carbon dioxide emissions. Notably, the PCEC process was financially and environmentally competitive with conventional SC only when achieving similar ethylene yields (ca. 50%). For an ethylene yield of ca. 25%, which is currently achievable using PCEC technologies, the capital investment and carbon emissions of the PCEC process were too excessive to outcompete electrified SC. The total energy usage, utility demand, and capital investment were substantially higher for the 25% ethylene yield PCEC case as compared to the 50% PCEC one, due to larger process streams and process units as a result of the lower single-pass yield. The results further highlighted that carbon emissions could be reduced from ca. 1.5 tCO2/tethylene to ca. 0.2 tCO2/tethylene when employing green electrified SC or PCEC processes instead of conventional fossil fuel-based SC, but only if fully renewable electricity was utilized. Moreover, a carbon tax of more than 100 USD/tCO2 would need to be imposed to make the green electrified SC and PCEC process more viable than their fossil-based counterparts. Lastly, technological challenges related to attainable ethylene yield, PCEC stability, large-scale sustainable production of PCECs, and the continuous availability of green electricity were identified as the main hurdles for the industrial implementation of PCECs for green ethylene production.