Abstract: Synthetic sintering-resistant calcium based material for high-temperature CO₂ capture was prepared by doping Al₂O₃ and MgO into CaO using wet chemical method. The synthetic materials with pore structure developed consist of three substances, CaO, Ca₃Al₂O₆ and MgO. Lower mass ratio of Ca₃Al₂O₆/MgO gives smaller grain size of the synthetic material. CO₂ capture capacities and cyclic carbonation/calcination (670/900℃) stability were evaluated in thermogravimetric analyzer under the simulated 10%(vol.,the same below) CO₂ (90% N₂). It is found that the synthetic CaO-Ca₃Al₂O₆-MgO material presents good performance to capture CO₂ from the flue gas, and the mass ratio of Ca₃Al₂O₆/MgO has significant effect on CO₂ capture performance. Lower mass ratio leads to faster carbonation reaction rate and higher CaO conversion. Moreover, the deactivation mechanism of synthetic material and the anti-sintering mechanism of doping agents were studied through analysis of specific surface area, pore volume, micro morphology, element distribution, phase composition and grain size of CaO-Ca₃Al₂O₆-MgO material after multicycle carbonation/calcination.

Key words: carbon dioxide, sorbents, deactivation, calcium oxide, alumina, magnesium oxide

摘要： 采用Al₂O₃和MgO同时掺杂改性的方法制备了CaO-Ca₃Al₂O₆-MgO复合钙基高温吸附CO₂材料。复合钙基材料孔隙发达，活性物相为CaO，惰性骨架物相为Ca₃Al₂O₆和MgO。Ca₃Al₂O₆/MgO质量比偏小的材料，表面微粒粒径较小。在10%（体积分数，下同）CO₂和90% N₂的混合气气氛下，采用热重分析仪测量了复合钙基材料吸附CO₂容量、碳化反应速率以及循环碳化（670℃）/煅烧（900℃）过程的稳定性。结果发现，复合钙基材料CaO-Ca₃Al₂O₆-MgO具有较好的吸附CO₂性能，提高Ca₃Al₂O₆/MgO质量比，合成材料的循环稳定性较好；降低Ca₃Al₂O₆/MgO质量比，合成材料的碳化反应速率加快，CaO转化率提高。最后，通过对不同循环次数下复合钙材料的比表面积、孔径分布、微观形貌、表面元素分布，晶相、晶粒大小进行研究分析，对合成材料的失活以及掺杂物质对烧结的抑制机理进行了讨论。

关键词: 二氧化碳, 吸附剂, 失活, 氧化钙, 氧化铝, 氧化镁