基于富氧燃烧锅炉的炉内和锅内过程耦合特性的研究

There are many differences between oxy-fuel and conventional combustion during the boiler designing and operation due to the changes in quantity and components of flue gas recycle. The project proceeds with the particle and gas radiation characteristic parameters in furnace, reveals the non-gray gas radiation calculation model and the variation of soot radiation behaviors, to obtain the medium radiation parameters in oxygen-enriched combustion boiler. The method of digital image processing technique and radiation heat transfer are used to reconstruct the three dimensional temperature field, for providing the decoupling analysis of furnace and steam-water in oxy-fuel combustion boiler. A mathematical model with temperature distribution and thermal parameters will be established by using the information of furnace, and the model of heat transfer and working fluid should be revised, such as the temperature of heating surface, the wall heat flux and so on. For the change rule of heat absorption in different radiation heating surfaces and thermal load, the characteristic of coupling and nonlinear between working medium and thermal load may be explored, and non-uniform heat response model in oxygen-enriched combustion boiler should also be obtained. And these new methods and theoretical principles for the research and development of oxy-fuel combustion boiler will be provided.

富氧燃烧煤粉锅炉的设计及运行因烟气组分和循环倍率的变化，导致与传统的空气燃烧有较大差异，开展其炉内燃烧、换热及其与锅侧蒸发系统响应特性的研究，是燃煤碳减排理论和装备放大规律解析的重要途径。本项目从炉内燃烧的介质颗粒及气体辐射特性等参数的分布特点入手，揭示非灰气体辐射在不同谱带的模型，探明烟黑颗粒相的辐射变化规律，获得富氧燃烧炉内介质的辐射特性参数；利用可视化检测技术和辐射传热分析方法，重建富氧燃烧炉内温度场，进而得到炉膛热负荷信息，为炉内和锅内过程的耦合分析提供条件；通过对富氧燃烧炉内传热、锅内工质流动的模型修正，建立富氧燃烧锅炉受热面壁温、壁面热流等热力参数与炉膛温度分布之间的数学模型，针对不同辐射区受热面的吸热和炉膛换热的变化规律，探究富氧燃烧锅炉的炉侧热负荷与锅内工质之间的耦合非线性特性，提出炉内和锅内过程非均匀传热响应模型，为富氧燃烧锅炉的研究和开发提供新的方法和理论基础。

针对碳氢火焰中碳烟生成机理研究，分析了富氧燃烧煤粉锅炉因烟气组分和循环倍率的变化，比较其与传统的空气燃烧的差异。本项目从炉内燃烧的介质颗粒及气体辐射特性等参数的分布特点入手，揭示非灰气体辐射在不同谱带的模型，探明烟黑颗粒相的辐射变化规律，获得富氧燃烧炉内介质的一维、二维辐射特性参数；利用模拟、检测和辐射传热分析方法，重建富氧燃烧炉内温度场，进而获得炉膛热负荷信息，为炉内和锅内过程耦合分析提供条件；通过对富氧燃烧炉内传热、锅内工质流动的模型修正，建立富氧燃烧锅炉受热面壁温、壁面热流等热力参数与炉膛温度分布之间的数学模型，探究富氧燃烧锅炉的炉侧热负荷与锅内工质之间的耦合非线性特性，提出炉内和锅内过程非均匀传热响应模型，在一台35MW富氧燃烧锅炉上开展了炉内燃烧、辐射换热及其与锅侧蒸发系统响应特性的诊断分析，并以此为基础深化了微纳尺度下的辐射传热研究。