Simultaneously enhancing H2 recovery and CO2 captured pressure during the hydrogen purification process of medium-temperature shifting gas by coupled wet CO2 separation-PSA technology: From laboratory to industrial scale test

The petrochemical industry has a significant demand for high-purity hydrogen. It primarily obtained from the H 2 purification unit by using pressure swing adsorption (PSA) technology to recover H 2 from medium-temperature shifting gas (MTSG). The the coupled wet CO 2 separation-PSA process was introduced in this work, aiming to capture CO 2 from MTSG while simultaneously increasing the H 2 recovery rate. To enhance the desorption pressure of CO 2 separation unit in the coupled process to facilitate the storage or utilization of the captured CO 2 , firstly, a rigorous thermodynamic study was carried out to provide a theoretical basis for the development of an improved CO 2 solvent. Subsequently, a pilot-scale test was executed to validate the theoretical findings. Finally, the patented coupled process was implemented at an industrial scale for the first time. The results showed that the capacity of PSA unit for H 2 purification increased from 6800 to 12,000 tons per year and the H 2 recovery rate increased from 84.6 % to 93.6 %; the CO 2 desorption pressure increased from about 0.03 MPa (traditional Benfield process) to 0.15 MPa, which reduced the energy consumption of CO 2 compression, and the total average annual economic benefits increased by US $ 15.55 million.