Process Modeling and Cost Estimation of CO2 and H2 Recovery From Syngas Using Exergy Analysis

Syngas, a vital feedstock in the chemical industry, consists of hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), and impurities such as hydrogen sulfide (H2S) and ammonia (NH3). Syngas is used in the production of ammonia, methanol, H2, and so forth. The impurities, such as H2S and CO2, are present in the syngas, which causes a decrease in the quality of syngas, and when H2S and CO2 are released into the air, they cause harm to the environment and contribute to global warming. In the research article, the syngas recovery process was modeled using Aspen Plus software and industrially validated. The Peng–Robson thermodynamic property method is used to simulate the process. The Peng–Robinson is used for hydrocarbons. The effect of the change of the number of distillation stages and the reflux ratio is studied to check the recovery of H2S and CO2 gas. The primary objective is to model and simulate the syngas recovery process. The second objective was to perform a parametric analysis of the process to investigate the effects of changing the number of distillation columns and reflux ratio, as well as studying the impacts of CO2 and H2S recovery and heat integration. In this analysis, the process stream of product steam is utilized to decrease the temperature of the feed stream. It reduced the utility cost of the inlet feed stream, resulting in a 0.03% decrease in cost. The third objective was to conduct a cost analysis of the process before the parametric analysis and the heat integration method to analyze the process's profit. This was due to the process recovering 1.06% H2S gas and 0.002% CO2, and calculating the utilities cost of the process. The fourth objective is an exergy analysis of the process in which the overall exergy destruction is 0.42%. The fifth objective was to use the simulation software ALOHA to model the dispersion of H2 gas. In the case, H2 gas is released into the air; it is a hazardous gas, destroying 1.2 mi. The proposed cryogenic approach achieves 85% CO2 removal, 99% H2S removal, and complete NH3 separation. Exergy analysis shows minimal energy losses, highlighting its advantages over solvent‐based techniques. The cost estimate further supports the approach's feasibility, indicating lower operating costs. This study offers a comparative assessment of syngas separation methods, with insights into energy efficiency and economic viability.