Hybrid solar-membrane cryogenic CO2 separation for coal power plants: An energy and sustainability perspective

In recent days, climate change has become a global concern, making the reduction of CO2 emissions a crucial step in mitigation efforts. Carbon capture, utilization, and storage is one of the most promising techniques for reducing CO2 emissions from large point sources. Cryogenic capture is one of the emerging CO2 separation methods. However, it demands a high energy penalty and high energy compared to the other processes. This is due to the lower concentration of CO2 in the flue gas. To overcome this issue, a solar-assisted membrane-cryogenic hybrid process has been developed. In this process, the concentration of CO2 is enriched using a membrane module. Further, CO2-enriched gas is purified by using the cryogenic process. The solar vapor absorption system is coupled with a membrane-cryogenic hybrid to save the compressor load. The compressor feed gas is pre-cooled with the help of solar Vapor absorption refrigeration (VAR); hence, the energy penalty of the compressor is reduced. The solar-assisted hybrid process's energy consumption is approximately 1.187 kJ/kg of CO2, achieving an overall recovery of 92.49% with a CO2 purity of 99.6%. This energy requirement is significantly lower compared to other conventional methods.