水泥分解炉内煤粉掺烧污泥的数值模拟研究

Numerical simulation on co-combustion of sewage sludge and pulverized coal in TTF precalciner

采用CFD理论数值模拟研究TTF型水泥分解炉内煤粉与不同含水率污泥的掺烧特性,模拟得到不同工况下炉膛内的温度分布、CaCO3和NO的浓度分布,并计算得到生料分解率和出口NO的平均浓度。模拟结果表明:煤粉中掺烧污泥对炉内温度场、生料分解和NO的生成排放产生一定程度的影响。污泥含水率一定的工况下,随着污泥掺混比的增加,炉膛整体温度、生料分解率和出口NO排放都有下降趋势;污泥掺混比一定时,随着污泥含水率的增加,也得到同样结论。分解炉内煤粉掺烧污泥可以有效抑制NO生成,降低出口NO的排放,同时会使得温度降低,生料分解率下降。因此,掺烧污泥的掺混比和含水率需限制在一定的合理范围内,才能够保证水泥的实际生产需要。模拟所得结果为该型分解炉的运行和优化提供理论依据。

Based on the theory of computational fluid dynamics(CFD),the co-combustion of pulverized coal and sewage sludge with different moisture content in a Trinal-sprayed calciner(TTF)precalciner were simulated.The temperature field,the concentration distributions of CaCO3 and NO were calculated under different working conditions.Also the decomposition rate of raw meal and the average NO concentration at the outlet were calculated.The results revealed that with the increase of sludge input under the constant moisture content of sludge,the average temperature of furnace,the decomposition rate of raw meal,and the NOx concentration all exhibited a downward trend.With the increase of moisture content of the sludge under the constant sludge input constant,the same trend occurred.Under the condition of ensuring the normal operation of precalciner,the moisture content of sludge and the sludge input should be in a reasonable range.These numerical results can provide reasonable instruction and theoretical basis for the design,operation and optimization of this type TTF precalciner.