Influence of ash composition on high temperature CO2 sorption

Abstract

To avoid increasing emissions of carbon dioxide to the atmosphere different approaches are being tested. One of them is based on adsorption process where new sorbents are still being developed and researched. Numerous studies consider physical or chemical adsorption promising for carbon dioxide capture from flue gas. Its competitiveness depends on finding a sorbent providing low acquisition cost combined with high stability and sorption capacity. Fly ashes from coal-fired power plants could accomplish these requirements and thus could be applicable for CO2 capture in industrial scale. Within this work different fly ashes were tested for CO2 capture and their physicochemical properties were determined to decide, which material is more suitable for high temperature CO2 chemisorption. It was confirmed that elemental composition, together with BET surface and pore size distribution, are important factors. Also other characterizations are, however, necessary to be measured to get all information potentially affecting the possible application in industry. Samples characterizations were performed by TGA, SEM, pore size analysis and X-ray fluorescence. The collected and evaluated data proved that certain fly ashes offered satisfactory capacities, which could be reached repeatedly after the appropriate thermal regeneration.