Low-Carbon Propylene Production using Chemical Looping Technology: A Comparative Study

Abstract

In this work, two chemical looping dehydrogenation processes, namely chemical looping oxy-dehydrogenation and chemical looping dehydrogenation, are presented and compared with the conventional propane-to-propylene catalytic route in terms of process efficiency, CO₂ emissions and costs through process simulation and techno-economic assessment. The chemical looping dehydrogenation achieves a conversion (per step) of 35% and selectivity of 93%, while the oxy-dehydrogenation shows a conversion of 15% and selectivity of 67%. As a result of these per-pass conversions, the downstream process purification has been designed accordingly. Compared to the conventional process, the chemical looping dehydrogenation could reduce CO₂ emissions by 28% (0.98 vs 1.37 ton_CO2/ton_C3H6 of the benchmark propane dehydrogenation) due to the inherent CO₂ concentration during reduction, which delivers CO₂ at high purity, unlike conventional furnaces. In terms of price, chemical looping dehydrogenation would reach a cost saving of 30 £/ton_C3H6 (4% lower). In case of the chemical looping oxy-dehydrogenation, the lower C₃H₆ yield exhibited is reflected in no saving in terms of CO₂ emissions (1.4 ton_CO2/ton_C3H6) with a cost increase above 23% (1023 £/ton_C3H6), making this configuration not of interest for industrial application unless a substantial improvement in material development.