Abstract:

A 10 kWth interconnected fluidized bed reactor (air reactor and fuel reactor) for chemical looping combustion was designed and built.The experiments on chemical looping combustion of biomass (sawdust) with NiO/Al₂O₃ oxygen carrier were performed in this reactor.The effects of fuel reactor temperature and steam/biomass ratio (S/B) on the gas composition of both fuel reactor and air reactor, combustion efficiency, etc., were discussed.The results indicated that the fuel reactor temperature was an important factor which affected the process of chemical looping combustion.With the increase of fuel reactor temperature, CO₂ content increased, and CH₄ content decreased evidently.CO content increased remarkably with increasing fuel reactor temperature in the temperature range 720—820℃, and reached its maximum at the temperature 820℃, and then decreased remarkably after the fuel reactor temperature exceeded 820℃.A higher fuel reactor temperature would contribute to increasing combustion efficiency.With the increase of steam/biomass ratio, CO and CH₄ content increased, CO₂ content and combustion efficiency decreased accordingly. In a total continuous operation time of 100 h, the oxygen carrier which was prepared by using impregnation exhibited extremely good oxidation-reduction reactivity and strong recycling ability.It was an ideal oxygen carrier for chemical looping combustion of biomass.

Key words:

化学链燃烧, 串行流化床, 载氧体, 生物质, CO₂分离

摘要：

设计并建立了10 kW_th级串行流化床化学链燃烧反应器系统，以NiO/Al₂O₃为载氧体，在该系统上进行生物质（松木木屑）化学链燃烧分离CO₂的试验研究，探讨了燃料反应器温度T、水蒸气/生物质比率S/B对两个反应器（空气反应器和燃料反应器）气体产物组成以及燃烧效率的影响。试验结果表明，燃料反应器温度是影响生物质化学链燃烧过程的重要因素，随着温度的升高，燃料反应器气体产物中CO₂浓度不断上升，CH4浓度显著降低，CO浓度先升高而后迅速下降;较高的反应器温度有助于燃烧效率的提高。随着S/B的增加，燃料反应器气体产物中CO和CH₄浓度均会增大，CO₂浓度以及燃烧效率有所降低。在100 h的连续试验过程中，采用共沉淀法制备的NiO/Al₂O₃载氧体展现出良好的氧化-还原性能和较强的持续循环能力，是生物质化学链燃烧理想的载氧体。

关键词:

化学链燃烧, 串行流化床, 载氧体, 生物质, CO₂分离