Effect Of Different Organic Compounds On CO₂ Capture Performance Of Modified Calcium-based Sorbent

Global warming caused by CO₂ and other greenhouse gases is becoming more and more serious.Reducing CO₂ emissions has caused widespread concern.As one of the most promising post-combustion CO₂ capture technology,CaO-based carbonation/calcination cycle CO₂ capture technology,referred to as calcium looping technology,has the advantages of wide source of precursor materials and large theoretical adsorption capacity;however,after several cycles,the performance of the calcium-based sorbent drops significantly,which restricts the industrial application of this technology.In order to improve the cycle performance,this article explores the modification of calcium-based sorbents with different organic matter components,and studies in detail the effects of different organic matter contents and inert frameworks on the CO₂ capture performance of the sorbents.Firstly,CaO sorbents were prepared by four organic calcium precursors and one inorganic calcium precursor,and their cycle reaction characteristics were compared in this thesis.After 50 cycles,the CaO sorbents prepared by the four organic calcium precursors have better CO₂ adsorption capacity than the inorganic calcium precursor.Among them,calcium lactobionate had the best CaO cycle performance,and the carbon capture capacity of the 50th cycle was still as high as 0.485g CO₂/g sorbent;the self-activation effect of CaO after calcined calcium lactate and calcium acetate appeared in the circulation process,and the carbon capture capacity was improved;The relationship between CaO adsorbent pores and CaO conversion rate was studied,and it was found that the specific surface area and pore volume had a high linear correlation with CaO conversion rate.Secondly,in order to improve the CO₂ capture performance of inorganic calcium,two organic substances,citric acid and gluconic acid,were added to the inorganic calcium precursor using the wet mixing method.The effects of different mass fractions of citric acid and gluconic acid on the CO₂ capture performance and microstructure of the calcium-based sorbents were studied,and it was found that the greater the amount of citric acid or gluconic acid added,the more developed the pores of the preparation are,the more fluffy the particles,and the better the circulating CO₂ capture capacity of the modified CaO;after 50 cycles,the CaO carbon capture capacity with citric acid can reach up to 0.452g CO₂/g sorbent,and the CaO carbon capture capacity with gluconate can reach up to 0.522g CO₂/g sorbent;compared with calcium citrate and calcium gluconate,the cyclic stability of CaO added with citric acid/gluconic acid was better;the modification effect of adding citric acid was slightly better than that of gluconic acid.Finally,in order to further enhance the cycle stability of the calcium-based sorbents,organic acids and atomic skeletons were added to the inorganic calcium at the same time.The effect of Mg O or Al₂O₃ doping on the CO₂ adsorption performance of calcium-based sorbents with organic acids was investigated.The greater the amount of organic acid added in different mass fractions,the better the CO₂ capture capacity of the composite sorbents;the addition of Mg O and Al₂O₃ both improved the cycling stability of the calcium-based sorbents,the effect of adding Al₂O₃ is more significant,and In the 20-cycle reaction,the CO₂ adsorption capacity of the calcium-aluminum sorbents decreased by only 19.09%at most,maintaining good stability.