CO2 adsorption on 13X binder free zeolite: effect of SO2 adsorption on CO2 capture

Abstract

Carbon dioxide (CO2) capture is a widely studied topic, and Carbon Capture and Storage (CCS) methods are gaining prominence, especially processes based on gas-solid adsorption. However, the literature lacks studies on the impacts of contaminants from gaseous streams, such as NOx, SOx, and humidity, on CO2 adsorption. The present study aims to evaluate the impact of sulfur dioxide (SO2) on CO2 capture under conditions analogous to the post-combustion scenario of biomass for bioenergy generation. For this purpose, adsorption data of 13X Binder Free (13XBF) zeolite were collected using a magnetic suspension balance (MSB), before different gas streams (CO2, N2, SO2 diluted in He (4500 ppm), CO2/SO2 diluted in He (4500 ppm), CO2/N2). It was observed that the presence of SO2 in the gas stream reduces the CO2 and N2 adsorption capacity of the zeolite. This reduction may be related to the decrease in textural properties after SO2 adsorption, resulting in a reduction of about 35% of the total pore volume. Finally, it was concluded that contact times of up to 3 hours between 13XBF and SO2 diluted in helium (4500 ppm) allow the recovery of the starting material. However, it was not possible to recover the starting material after a contact time of 12 hours at 50, 70, or 90°C. Thus, suggesting the need for pre-treatment of the gaseous stream before moving on to CCS Technologies. Therefore, it is recommended that future studies be conducted to evaluate the critical time for SO2 adsorption to become irreversible and to understand the effect of other contaminants (such water vapour, CO, and NOx) present in combustion gases, given the gap identified in the literature, and utilization of molecular simulation tools to carry out a study at the molecular level to assess the competition between CO2 and SO2.