A novel Rectisol process for H2S enrichment and CO2 capture: Process optimization and thermodynamic analysis

Rectisol process can effectively and selectively remove hydrogen sulfide and carbon dioxide from the raw gas. With the growth of the demand for carbon dioxide capture, the Rectisol process becomes an important method for capturing carbon dioxide. A reasonable carbon dioxide capture structure in the Rectisol process can not only alleviate the process burden, but also contribute to reducing carbon dioxide emission. Therefore, a novel Rectisol process for H2S enrichment and CO2 capture is proposed in this paper. It integrates a H2S enrichment process and a CO2-lean solvent circulation process into the Rectisol process. And an optimization framework is proposed to optimize the process parameters using the TOPSIS method. According to the process evaluations in technology, economy and environment, the novel process demonstrates its excellent economic and environmental benefits compared with the typical process. The carbon sulfur ratio, return on investment and carbon dioxide capture ratio of the novel process are 2.09, 15.24 and 0.69 respectively. The novel process can reduce the consumption of low-temperature cold energy, but its exergy efficiency still needs to be improved from the thermodynamic analysis. It is beneficial to energy conservation but detrimental to energy conversion. This study provides a new idea for the development of Rectisol process. It can achieve the energy conservation and emission reduction.