A hybrid separation process for the recovery of carbon dioxide from flue gases

Due to the low CO2 concentrations in flue gases (below 20vol.%), the adequate recovery and purity of carbon dioxide in the product can only be achieved by using two-stage adsorptive or membrane systems. In these systems, the high recovery is commonly obtained by minimising CO2 content in the gas leaving stage 1 and recycling the CO2 that remains after stage 2 to the inlet of the installation. The hybrid technique is an obvious extension of the two-stage adsorptive or membrane process. However, there are a number of problems that have to be tackled before such a system becomes practically attractive. One of these problems is the sequence in which the two sections (adsorption and membrane separation) are incorporated into the complete installation. Preliminary studies show that, in the case of flue gas purification, the adsorptive section based on pressure swing adsorption (PSA) should come first In the present paper results of detailed numerical simulations are presented for the arrangement proposed. A demonstration installation processing around 10 m(3)(STP)/h of the flue gas is briefly described. (C) 2013 The Authors. Published by Elsevier Ltd.