镁负载CaO基吸附剂捕集CO2性能及抗烧结机理

复合钙基吸附剂制备成本过高是限制其工业化应用的主要瓶颈问题。本文以不可溶的CaCO₃和Ca(OH)₂作为钙源，通过燃烧合成法制备钙镁复合吸附剂，在双固定床反应器上研究了其循环捕集CO₂性能。结果显示：制备得到的钙镁复合吸附剂具有更发达的孔隙结构，吸附剂表面Ca和Mg分散均匀，MgO均匀分布于CaO晶粒之间，有效提高了钙镁复合吸附剂的抗烧结特性，因此钙镁复合吸附剂循环反应过程中具有高捕集CO₂活性。以Ca(OH)₂作为钙源时，燃烧合成过程中Ca和Mg均匀同时析出，分散更加均匀，有效避免了CaCO₃作为钙源时Mg的团聚问题，因此得到的钙镁复合吸附剂循环捕集CO₂性能最优。最佳的Ca/Mg摩尔比为(8∶2)~(7.5∶2.5)。本研究以不可溶钙源制备得到高活性钙镁复合吸附剂，有效控制了吸附剂成本，具有更好的工程应用前景。

CO2 capture capacity and anti-sintering mechanism of MgO supported CaO based sorbent

The costs for the synthesis of calcium based sorbents are quite high, which has severely limited their industrial application. In this article, insoluble CaCO₃ and Ca(OH)₂ were used as raw materials to synthesize CaO/MgO sorbents by solution combustion. The CO₂ capture capacity of the synthesized sorbents was investigated in a double fixed-bed reactor. The results showed that the CaO/MgO sorbents presented highly porous microstructures, with MgO uniformly distributed on the surface of CaO and their anti-sintering performance was improved obviously. Therefore, the CaO/MgO sorbents showed much higher CO₂ capture capacities. When Ca(OH)₂ was used as calcium precursor, the Ca and Mg crystallized simultaneously during the solution combustion process and distribute more evenly on the obtained sorbent. The optimum Ca/Mg molar ratio range was (8∶2)~(7.5∶2.5). The synthetic cost is effectively controlled by using insoluble calcium precursors as raw materials and hence the produced CaO/MgO sorbent here has a better engineering application prospect.