CO2 and H2O Capture from High Humidity Flue Gas by Single Multi-Layer Vacuum Swing Adsorption Unit

The working capacity of 13X zeolite was considerably reduced when feeding a vacuum swing adsorption (VSA) carbon capture process with a high (~10%) water humidity level gas stream. To effectively tackle the water issues in real flue gas and keep the capital costs at a economical level without adding any pre-drying equipment, multiple-layer VSA technology was investigated in this study. Three configurations of multi-layer experiments were designed and conducted: double layers with 13X and Sorbead, triple layers with LiX zeolite +13X+Sorbead and triple layers with 13X+Sorbead+ACF. Experimental results showed that the water front was successfully contained within the pre-layers at cyclic steady states. More importantly, our one-bed systematic cyclic experiments could concentrate CO2 from 12% to 61% with a CO2 recovery of 77% under the double-layer configuration. Meanwhile, as a comparison, the LiX triple-layer experiment yielded a good CO2 recovery of 81% and productivity of 0.0132 mol/(kg•h) under the same operational condition as double layers. The ACF triple-layer experiments illustrated that the water front was retained better than the double layer case due to the larger water adsorption capacity of ACF though a higher pressure drop was observed as result of tight packing.