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针对富氧燃烧方式下烟气中高浓度H2O和CO2混合气体的辐射换热问题,建立了一种改进的宽带关联(IWBCK)分布模型.为了验证IWBCK模型计算的有效性,首先选取不同配比的H2O/CO2混合气体进行计算分析,并与逐线计算和基于指数的宽带关联k分布模型进行对比,表明IWBCK模型对H2O/CO2混合气体的处理较合理,与逐线计算的结果更加接近;以某电站300MW燃煤锅炉为例,采用IWBCK模型计算了空气燃烧方式下三原子气体的辐射特性,并与前苏联锅炉机组热力计算标准的计算模型进行了对比分析,结果表明:两种模型的计算结果基本吻合,说明IWBCK模型对空气燃烧方式也是有效的.基于分区段热力计算的方法,采用IWBCK模型分别计算了该锅炉在空气燃烧方式和富氧燃烧方式(30%O2/70%CO2)下各区段三原子气体的吸收系数和发射率,结果表明:在不同温度下,富氧燃烧方式下三原子气体的吸收系数和发射率有不同程度的提高,辐射换热加强.
In order to verify the validity of the IWBCK model, an improved IWBCK distribution model is established for the radiation heat transfer of high concentration H 2 O and CO 2 mixed gas in flue gas under oxygen rich combustion mode. First, H 2 O / CO 2 mixed gas is calculated and compared with the line-by-line calculation and the exponential-based broadband k-distribution model. The results show that the IWBCK model is more reasonable for the H 2 O / CO 2 gas mixture and closer to the line- Taking a 300MW coal-fired boiler of a power plant as an example, the radiation characteristics of the triatomic gas under air-combustion mode are calculated by IWBCK model, and compared with the calculation model of thermal calculation standard of the former Soviet Union boiler unit. The results show that the calculation of the two models The results are basically in agreement, indicating that the IWBCK model is also effective for air combustion method.Based on the method of sub-zone thermodynamic calculation, IWBCK model is used to calculate the air-combustion mode and oxy-combustion mode (30% O2 / 70% CO2) The absorption coefficient and emissivity of triatomic gas in each section show that at different temperatures, the absorption coefficient of triatomic gas under oxygen-rich combustion mode and There are different levels of reflectivity increase, radiative heat transfer strengthened.