Pressure Swing Adsorption Process in Coal to Fischer-Tropsch Fuels with CO2 Capture

Abstract

The carbon dioxide capture by pressure swing adsorption in a coal to Fischer-Tropsch process is addressed. The simulations results show that a (hydrogen + carbon monoxide) product with required composition for Fischer-Tropsch synthesis, H-2/CO ratio of 2.22, and inerts content of 3.90% can be obtained. Additionally, the PSA process produces high purity carbon dioxide of 95.16% with high recovery of 91.6%. This CO2 stream is compressed to 110 bar for transportation and storage. The power consumption requirement was calculated to be 311 kW.h/ton(CO2) (191 kW.h/ton(CO2) for separation and 120 kW.h/ton(CO2) for compression), which is too high for competitive operation of the PSA process when compared to absorbent based processes. A modification of the PSA process operation procedure involving the introduction of a number of tanks to collect fractions of the blowdown stream drastically reduces the power consumption to 129 kW.h/ton(CO2) (including separation and compression to 110 bar) without affecting the products specifications.