Abstract

The optimization of the boiler furnace’s aerodynamics is considered in order to increase the efficiency of burning power-generating fuel by the example of burning lean Kuznetsk coal in a solid slag removal scheme. Combustion options have been proposed and investigated in schemes with direct injection of coal dust and with an intermediate coal dust hopper. The schemes use direct-flow burners with an counter-displaced arrangement and nozzles with a downward inclination, and staged combustion of fuel is used. A study of the furnace’s aerodynamics on an isothermal bench was carried out. The results of physical modeling were compared with the data of numerical modeling of an isothermal bench. It is noted that combustion schemes differ in the intensity of vortex formation in the active combustion zone. A numerical simulation of fuel combustion in the boiler furnace was performed using the two indicated combustion schemes. The purpose of the simulation was to obtain the distribution of temperatures, gas velocities, concentrations of combustion products, nitrogen oxide emissions, degree of burnout in the furnace volume and other characteristics that affect the efficiency, reliability, and environmental safety of the boiler. The results of model studies showed that the developed schemes provide high efficiency of burning lean Kuznetsk coal with solid slag removal and, at the same time, low emissions of nitrogen oxides. An additional verification of the numerical model was carried out by comparing the gas temperatures by the height of the furnace obtained by its numerical simulation and thermal zone calculations. A comparison of the temperatures of the gases at the outlet of each zone showed their good agreement (the difference was no more than 30°C).

中文翻译：

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直流燃烧器炉内固体燃料燃烧过程的研究

摘要

为了提高燃烧发电用燃料的效率，以固体贫渣去除方案中燃烧稀薄的库兹涅茨克煤为例，对锅炉炉的空气动力学进行了优化。已经提出了燃烧选择方案，并在直接注入煤尘和使用中间煤灰斗的方案中进行了研究。该方案使用具有反向移位布置的直流燃烧器和向下倾斜的喷嘴，并使用分段燃烧的燃料。在等温工作台上对熔炉的空气动力学进行了研究。将物理建模的结果与等温工作台的数值建模数据进行了比较。要注意的是，燃烧方案在活动燃烧区中的涡流形成强度上是不同的。使用两个所示的燃烧方案进行了锅炉炉内燃料燃烧的数值模拟。模拟的目的是获得温度，气体速度，燃烧产物的浓度，氮氧化物的排放，炉膛内燃尽程度以及影响锅炉效率，可靠性和环境安全的其他特征的分布。模型研究的结果表明，所开发的方案可有效燃烧稀薄的库兹涅茨克煤，并去除固体炉渣，同时还减少了氮氧化物的排放。通过将气体温度与通过数值模拟和热区计算获得的炉膛高度进行比较，对数值模型进行了额外的验证。