Ca-Fe／bentonite载氧体煤化学链燃烧反应特性

A Ca-based compound oxygen carrier was prepared with industrial grade natural anhydrite, bentonite (ben) and iron nitrates by using the mechanical mixing-prilling method. The experiments were carried out in a fluidized bed with steam as the gasification-fluidization medium. The influence of active component content, temperature as well as multi-cycle on the reactivity between CaSO 4 /bentonite and coal was investigated. The results show that the CaSO 4 mass content of 60% and the adding Fe 2 O 3 can make a better reactivity and less attrition of the oxygen carrier particles. The attrition rate is 0.089%/h. The time to reach a carbon conversion of 95% is shortened to 20.8 min, and the average dry concentration of CO 2 approaches 95.99%. Ten redox tests demonstrate that the concentration of CO 2 can be kept in 80% and the CaSO 4 -Fe 2 O 3 /ben (Ca-Fe/ben) oxygen carrier has a good cyclic stability. Moreover, four types of coal are tested, indicating that the coals with high volatile content and high ash content have higher combustion efficiencies with above 90% CO 2 concentration in gasification products in all cases.