(736b) Life Cycle Assessment of a Chemical Looping Hydrogen Production Process with Varied Reducer, Oxidizer, and Combustor Pressures
AIChE Annual Meeting
Wednesday, November 17, 2021 - 4:00pm to 4:30pm
H2 is an essential industrial chemical and a promising clean fuel for the future. However, the current methods for H2 production, such as steam methane reforming (SMR), can lead to significant amount of CO2 emissions, and the global warming potential (GWP) of a typical SMR process is approximately ~12 kg CO2eq/kg H2. In order to reduce the CO2 emissions associated with H2 production, CO2 capture units can be integrated into SMR processes. However, this usually results in considerable reduction in energy efficiency and H2 yield of the process. This research studies a chemical looping process that converts natural gas into H2 with high energy efficiency and 100% CO2 capture. The process is simulated and optimized in ASPEN Plus to maximize H2 yield while achieving autothermal operation. Then, the life cycle assessment (LCA) is performed on this process to compare its global warming potentials with the conventional SMR processes with and without CO2 capture. The calculation shows that the chemical looping process only has a GWP of ~5 kg CO2eq/kg H2. This GWP can be further reduced when a varied pressure operating strategy is implemented into the chemical looping process, allowing the reducer, the oxidizer, and the combustor to operate at different pressures. With this strategy, the GWP can be further reduced to 3 kg CO2eq/kg H2. This research demonstrates the great advantage of chemical looping technology in reducing the greenhouse gas emissions associated with H2 production from traditional fossil fuels.