Impact of Pressure and Temperature Elevation on Activated Fly Ash Cubes During Carbon Dioxide Adsorption for Carbon Capture Applications

Abstract Carbon dioxide (CO2) capture is one of the most promising technologies for greenhouse gas emissions reduction. This research studies the ability of a fly ash generated from coal slag to capture CO2 directly via low energy adsorption. Experiments investigated the impact of the fly ash shape, contact surface area, temperature, CO2 injection rate, helium injection rate and mixture on the CO2 adsorption capacity. The results were then compared to those of activated carbon samples, also tested in this research. The samples were shaped into cubes and hemispheres using a mixture of fly ash, alkaline activator, and water. Results showed that the fly ash had an extremely high adsorption capacity for CO2 which indicates its ability to capture and store CO2. The cubic samples managed to adsorb a higher CO2 concentration compared to the hemispherical samples. As the temperature increased, the CO2 adsorption capacity increased due to sample expansion which resulted in an increase in in the contact surface area between the CO2 and the fly ash which increased the available adsorption sites. Increasing the CO2 injection rate has an initial positive impact, which was then reduced due to the high rate of CO2 which reduced the ability of the molecules to adsorb. Finally, the fly ash exhibited a high adsorption potential compared to the activated carbon.