Energy-efficient process design and optimization of the absorption-based CO2 capture process with a low-pressure flash column for the SMR-based hydrogen production plant

Abstract

The introduction of CO2 capture processes is being considered as a transitional solution to the energy paradigm shift and various process design studies are carried out for achieving high energy efficiency. Technical maturity and commercial availability of amine-based capture systems enables the production of blue hydrogen production through steam methane reforming (SMR), which can effectively meet the ever-increasing demand for hydrogen. In this study, an amine-based CO2 capture process integrated with a low-pressure flash column is investigated to improve our understanding on energy-efficient blue hydrogen production, in which the high-pressure condition of synthesis gas discharged from the shift converter is fully exploited. Process optimization is performed through sensitivity analysis of key design parameters. By introducing the low-pressure flash column and semi-lean solvent stream, the specific reboiler duty of the optimized process can be decreased down to 0.510 GJ/tonneCO2, which is about 79.5% reduction in thermal energy consumption and 59.2% energy saving, compared to the conventional process. The economic trade-off between energy consumption and equipment cost is carried out, which provides practical design guidelines for improving the energy efficiency of capture processes and conceptual insights for the techno-economic impact of CO2 capture on hydrogen production.