富氧煤粉燃烧锅炉炉内过程仿真模型研究

Research on Simulation Model of Inter-Boiler Process of Oxygen-enriched Combustion of Pulverized Coal

以某300MW富氧煤粉燃烧锅炉炉膛为对象,根据炉内的流动、燃烧和换热等过程机理,采用集中参数法建立了富氧煤粉燃烧锅炉炉内过程的仿真模型,该模型主要考虑到炉内的燃烧和换热,对不同负荷条件下炉内燃烧和换热进行计算。在炉内辐射换热过程计算中,考虑到气体辐射对波长的选择性,采用了更接近工程实际的气体-灰壁面模型进行计算。进行了不同负荷条件下静态仿真计算及燃煤量与再循环烟气的扰动试验,对炉膛压力、水冷壁辐射换热量和炉膛出口烟温的静态和动态特性进行了研究。发现随着负荷的增加,炉膛出口烟温与水冷壁辐射换热量的过渡时间缩短,对动态响应更加敏感,可为富氧煤粉锅炉炉膛的控制系统设计和机组安全运行提供一定参考。

Taking the furnace of a 300 MW oxygen-enriched pulverized coal boiler as the research object, based on the mechanism of flow, combustion and heat transfer process, the dynamic simulation mathematical model of inter-boiler process of oxygen enriched pulverized coal boiler was established using the method of modular modeling, the model could simulate combustion and radiative heat transfer in a oxygen-enriched pulverized coal boiler furnace. Considered the gas radiation of wavelength selectivity, a gas-grey wall model in the radiation heat transfer progress of the furnace was used. A static simulation test, the fuel flow test and the flue gas recirculation test were conducted under different load conditions. The static and dynamic characteristics of furnace pressure, the radiation heat transfer of waterfall and the temperature of outlet flue gas from boilers were completed. It was found that the changing trends of overheat system are similar under different load conditions. With the raising of boiler load, the transition time of export steam temperature variation and the radiation heat transfer of waterfall are cutting short and the response to each disturbance is more sensitive, which can provide reference for the control system design of oxygen enriched pulverized coal boiler and the safe operation of the unit.