(736b) Life Cycle Assessment of a Chemical Looping Hydrogen Production Process with Varied Reducer, Oxidizer, and Combustor Pressures

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.