基于镍基修饰的铁矿石载氧体煤化学链燃烧实验

使用1 kW_th串行流化床反应器,研究了以铁矿石为载氧体以及对铁矿石进行镍基修饰情况下煤化学链燃烧特性,对两种修饰方法(机械混合和浸渍)进行了对比评价。结果表明,铁矿石载氧体具有良好的反应性能和稳定性,是实现煤化学链燃烧的一种比较理想的载氧体。向矿石中机械添加少量NiO/Al₂O₃载氧体,能够有效改善其反应活性,提高系统CO₂捕集率;采用浸渍法修饰的铁矿石载氧体煅烧后,总体微观孔隙结构变差,导致煤气化产物与载氧体间的反应无法充分进行,系统CO₂捕集率显著下降。浸渍修饰的方法和过程需要进一步的研究和改善。

Experimental investigation of hematite oxygen carrier decorated with NiO for chemical looping combustion of coal

Experiments on chemical looping combustion were conducted in a 1 kWth interconnected fluidized bed reactor using a natural hematite as oxygen carrier and Shenhua bituminous coal and Huaibei anthracite as fuel.An evaluation of hematite oxygen carrier decorated with NiO by mechanical mixing and impregnation methods was also performed.The results indicate that coal gasification rate is a time limiting step in chemical looping combustion of coal and the coal type has a great impact on CO2 capture efficiency.When fuel reactor temperature is 970 ℃ and hematite as oxygen carrier,CO2 capture efficiency for Shenhua bituminous coal is 81.7%,whereas the one for Huaibei anthracite is 65%.Hematite shows stable reactivity in a process of long-term operation and it should be a good candidate of oxygen carrier for chemical looping combustion of coal.It is an effective way to improve the reactivity of hematite oxygen carrier as well as CO2 capture efficiency by mechanical mixing with NiO/Al2O3 oxygen carrier.Impregnating NiO on hematite shows a negative effect of reaction performance between product of coal gasification and oxygen carrier due to the poor microstructure after calcination.Further investigations on method and process of impregnation should be done.