流化床锅炉温度条件下钙基工业废弃物的固硫反应性能

在流化床锅炉温度条件下研究了赤泥、电石渣等钙基工业废弃物煅烧后的固硫特性,并与石灰石比较,同时研究了吸收剂在反应过程中的物相变化、微观结构特性。结果表明,在相同反应条件下,随反应时间增加,赤泥的钙转化率高于电石渣和石灰石,石灰石的钙转化率最小。赤泥和电石渣的最佳固硫温度分别为850～900℃和950～1000℃。随SO2浓度增加,在相同反应时间内赤泥的钙转化率和硫化反应速率也相应增大。粒径对赤泥的固硫性能影响不大。赤泥和电石渣中钙的主要化合物分别为Ca2SiO4和Ca(OH)2。它们煅烧后孔径主要分布在5～20nm内,这正是最有利于固硫的孔径区域,石灰石煅烧后孔径主要分布于45～420nm。钙基废弃物具有优良的孔隙结构,因而它们在流化床锅炉温度条件下具有良好的固硫性能。

Capturing sulphur behavior of calcium-based industrial waste at fluidized bed boiler temperature

The behavior of capturing sulphur by calcined calcium-based industrial wastes such as red mud and carbide slag was evaluated at fluidized bed boiler temperature and compared with that of limestone.The change of phase and microstructure for these materials during reaction was characterized.The results show that with increase of reaction time the calcium conversion is higher in red mud than in carbide slag, and that in limestone is the smallest under the same conditions.The optimum temperature for sulphur capture is 850-900℃ for red mud and 950-1000℃ for carbide slag.With increase of SO_2 concentration the calcium conversion and the rate of sulfuration reaction for red mud increases for the same reaction time, and the effect of particle size on sulfur capture of red mud is not significant.Ca_2SiO_4 and Ca(OH)_2 are main calcium compounds in red mud and carbide slag, respectively.The range of pore size for calcined red mud and carbide slag is 5-20 nm that is the most favorable for sulfur capture, while that for calcined limestone is 45-420 nm.These calcium-based industrial wastes are of better performance of capturing sulfur at the fluidized bed boiler temperature because of their suitable pore structure.