摘要：

化学链燃烧是一种具有CO₂内分离特性的燃烧方式。以赤铁矿为载氧体，在1 kW_th级串行流化床上进行了煤化学链燃烧试验。讨论了燃料反应器温度对气体产物组分的影响；比较了各反应参数对煤气化效率、煤气化产物的转化效率及碳捕集效率的影响情况，分析了煤中硫的排放问题。试验结果表明：温度由900℃升高到985℃，燃料反应器中CO体积份额逐渐增加，CO₂体积份额逐渐减小，空气反应器中CO₂浓度呈线性下降。燃料反应器温度的升高促进煤气化效率及碳捕集效率大大提高。载氧体量和系统负荷是煤气化产物转化效率的主要影响因素，载氧体量的增加和负荷的增加分别会使煤气化产物转化效率提高和下降。燃料反应器中的硫主要以SO₂形式存在于燃料反应器，随温度的升高，SO₂浓度由515×10^-6逐渐增加到562×10^-6

关键词: 串行流化床, 煤, 化学链燃烧, 载氧体, 铁矿石

Abstract:

Chemical looping combustion is a promising technology for the combustion of fuel with inherent separation of CO₂.The experiments on chemical looping combustion of coal were performed in a 1 kW_th interconnected fluidized bed reactor using a natural Australian hematite as oxygen carrier.The effects of fuel reactor temperature on the gas compositions from both fuel and air reactors were discussed.A comparison of the effects of several factors on coal gasification efficiency, carbon capture efficiency and gasification products conversion efficiency was carried out and the gaseous sulfur compounds released in the system were analyzed.The results indicated that with increasing fuel reactor temperature from 900℃ to 985℃ there was a gradual increase of CO volumetric fraction but a gradual decrease of CO₂ volumetric fraction in the fuel reactor, and CO₂ concentration in the air reactor dropped linearly correspondingly.A higher fuel reactor temperature would contribute to significantly increasing coal gasification efficiency and carbon capture efficiency.An increase in the mass of oxygen carrier and coal, the main factors, would cause the gasification conversion increase and decrease respectively.Sulfur was released primarily as SO₂ in the fuel reactor, and SO₂ concentration increased from 515×10^-6 to 562×10^-6 due to a change in fuel reactor temperature from 900℃ to 985℃.

Key words: 串行流化床, 煤, 化学链燃烧, 载氧体, 铁矿石