An efficient temperature swing adsorption (TSA) process for separating CO₂ from CO₂/N₂ mixture using Mg-MOF-74

Carbon dioxide emitted from fossil fuel burning processes is quantitatively the most contributor to global warming. It is believed that climate change could be mitigated by means of Carbon Capture and Storage (CCS). CO₂ physical adsorption separation has the potential of capture carbon dioxide with minimum energy costs. A special type of metal organic frameworks named Mg-MOF-74 is an exceptional adsorbent amongst other porous materials with high CO₂ uptake at flue gas conditions. Temperature swing adsorption (TSA) composed of 4 steps (feed, rinse, heating, and cooling), for separating CO₂ from CO₂/N₂ mixture using Mg-MOF-74; has been mathematically modeled. A computer model implementation was developed employing User-Defined-Functions linked to Ansys-Fluent software. The CFD two- and three-dimensional models have been validated against adsorption breakthrough experimental data obtained by the authors, at ambient temperature, and against published experimental data for high temperature conditions. The regeneration (heating and cooling) time has been tuned to explore the performance improvement for the TSA process. The TSA optimal key performance indices in terms of CO₂ purity, recovery, productivity, and process power consumption have been found to be 96.22%, 86.5%, 0.279 kg of CO₂ per hour per kg of Mg-MOF-74, and 663.8 kWh per ton of CO₂ captured, respectively. These productivity and power consumption values showed a substantial enhancement in the CO₂ adsorption separation compared to those reported in the literature, especially when the heating process is used for the desorption part of the process.