Study on Adsorption Mechanism and Failure Characteristics of CO(2) Adsorption by Potassium-Based Adsorbents with Different Supports

In order to obtain the adsorption mechanism and failure characteristics of CO(2) adsorption by potassium-based adsorbents with different supports, five types of supports (circulating fluidized bed boiler fly ash, pulverized coal boiler fly ash, activated carbon, molecular sieve, and alumina) and three kinds of adsorbents under the modified conditions of K(2)CO(3) theoretical loading (10%, 30%, and 50%) were studied. The effect of the reaction temperature (50 °C, 60 °C, 70 °C, 80 °C, and 90 °C) and CO(2) concentration (5%, 7.5%, 10%, 12.5%, and 15%) on the adsorption of CO(2) by the adsorbent after loading and the effect of flue gas composition on the failure characteristics of adsorbents were obtained. At the same time, the microscopic characteristics of the adsorbents before and after loading and the reaction were studied by using a specific surface area and porosity analyzer as well as a scanning electron microscope and X-ray diffractometer. Combining its reaction and adsorption kinetics process, the mechanism of influence was explored. The results show that the optimal theoretical loading of the five adsorbents is 30% and the reaction temperature of 70 °C and the concentration of 12.5% CO(2) are the best reaction conditions. The actual loading and CO(2) adsorption performance of the K(2)CO(3)/AC adsorbent are the best while the K(2)CO(3)/Al(2)O(3) adsorbent is the worst. During the carbonation reaction of the adsorbent, the cumulative pore volume plays a more important role in the adsorption process than the specific surface area. As the reaction temperature increases, the internal diffusion resistance increases remarkably. K(2)CO(3)/AC has the lowest activation energy and the carbonation reaction is the easiest to carry out. SO(2) and HCl react with K(2)CO(3) to produce new substances, which leads to the gradual failure of the adsorbents and K(2)CO(3)/AC has the best cycle failure performance.