Experiments On CO₂ Absorption Performance And Preparation Process Of Calcium-based Sorbent Particles With High-aluminum Cement Addition

Carbon dioxide trapping processes such as chemical chain gasification and calcium-based recycling based on calcium-based adsorbents have received considerable attention in recent years due to the efficient and low-carbon utilization of carbonaceous fuels such as coal and biomass.However,there are still problems in that the absorption efficiency is significantly reduced after repeated cycles of absorption.In response to this problem,the main solutions at present are the addition of inert additives to natural limestone or preparing absorbents by different preparation methods.In this regard,this paper first explores the cycle characteristics of natural limestone.Then,the preparation process,additive substances and doping ratio of calcium-based adsorption particles are explored.Finally,the calcium-based adsorption particles obtained by adding 5%by mass of high-aluminum cement to natural limestone by hydration have better adsorption effect.Then,exploring the effect of carbonization/calcination atmosphere on the absorption efficiency of new calcium-based adsorption particles.In the fluidized bed,it is verified that the new calcium-based adsorption particles have better absorption efficiency and anti-abrasion characteristics,and provide corresponding technical support for industrial applications.The carbonization/calcination rate of natural limestone was studied by thermobalance.The carbonization temperature?600⁸00??,calcination temperature?850¹000??and the particle size of the absorbent were studied on the natural limestone carbonization/calcination in the tube furnace.The effect of cycle characteristics and the microscopic pore structure of the absorbent at different carbonization temperatures were analyzed by SEM.The experimental results show that the conversion rate of natural limestone in the first three minutes of carbonization and calcination reaction can reach about 90%;the optimum carbonization temperature is 700?,the optimum calcination temperature is 850?,and the smaller the reaction particle size,the higher the absorption efficiency after the same number of reactions.It can also be seen from the SEM image that the particles is serevely coked after repeated cycles.In view of the serious coking problem of natural limestone after repeated cycles,this paper proposes to add high-alumina cement to natural limestone to improve the structural characteristics of the absorbent.Then selecting preparation methods,additives and addition ratios.The effect of carbonization/calcination atmosphere on the cycle characteristics of the new calcium-based absorbent was studied,and the anti-abrasion properties of the absorbent were analyzed.The result shows that the new calcium-based absorbent,adding 5%high-alumina cement to the nature lime by hydration,has good absorption efficiency and anti-abrasion performance.After 20cycles,the absorption efficiency is 0.51,which is 14.7%higher then nature lime,and the wear rate is only about 29%of natural limestone.The mechanism of excellent performance of the new calcium-based absorbent was analyzed by SEM,nitrogen adsorption test,XRD and particle model calculation.At the same time,the new calcium-based absorbent has the maximum CO₂ carbonization concentration when carbonized,and the absorption efficiency increases with the increase of the CO₂concentration in the atmosphere before the concentration,and the absorption efficiency does not change after the concentration is exceeded.The lower the CO₂content in the calcination atmosphere,the higher the absorption rate of the absorbent.After the preparation of the new calcium-based adsorption particles and their cycle characteristics,the cycle characteristics of natural limestone and new calcium-based adsorption particles were tested on a small fluidized bed.The experimental results show that new calcium-based adsorption particles still have an high absorption efficiency,about 0.44,which is about 0.15 higher than that of natural limestone.At the same time,after 20 cycles,the wear amount is only about 60%of natural limestone,which proves that the new calcium-based adsorbent particles have good absorption performance and good wear resistance,which can meet industrial applications.