High temperature absorbents for CO2 capture

Publisher Summary The development of suitable low-cost, regenerable absorbents with long lifetime is one of the major challenges of the high temperature CO2 capture. The purpose of the experiment described in this chapter is to carry out a screening of natural minerals that are able to take up CO2 in a reversible manner. The selected minerals were characterized in terms of absorption capacity, cycle stability, and mechanical stability. Furthermore, the influence of different parameters such as presence of steam, particle size, and sorbent loading degree on the cycle stability was investigated. The tested minerals were selected among different classes of carbonates and silicates. Thermogravimetric analysis was performed employing a Netzsch apparatus STA 409 CD. Experiments were conducted in isothermal and quasi-isothermal manner. The quasi-isothermal experiments were carried out in controlled gas flow atmosphere. The chemical/cycling stability is dependent on the chemical composition of the minerals; an increased concentration of inert components influences positively the cycling stability of the sorbent materials. Natural complex silicates containing calcium carbonate showed poor CO2 sorbent qualities, however, they produced good cycling and mechanical stability results. The presence of steam in the gas atmosphere increases the absorption reaction rate, but reduces the sorbent lifetime. Crushing and milling can influence the absorption behavior of the sorbents due to the change of their chemical composition.