电站锅炉燃用高灰分烟煤低负荷再热汽温的研究

Study on the reheat steam temperature of a utility boiler at low load burning high ash bituminous coal

辽宁某电厂锅炉燃料属高灰分烟煤,机组低负荷运行时再热汽温显著偏低,制约节能发电。为研究低负荷再热汽温特性,并分析锅炉节能改造潜力,开展煤种燃烧特性试验、燃烧设备调试及煤种掺烧性能测试研究。结果表明,燃用设计煤或低热值煤锅炉低负荷再热汽温大幅度偏低,高灰分高挥发煤"短促燃烧"特性是锅炉低负荷再热汽温偏低的主要原因之一。为提高低负荷再热汽温,建议大幅度减小燃烧器喷口的安装切圆直径,并适当调整过、再热系统对流受热面积的分配比例。

The boiler fuel of a power plant in Liaoning belongs to high ash bituminous coal,the reheat steam temperature of the unit is significantly low during low load operation,which restricts the energy-saving in power generation.In order to study the reheat steam temperature characteristics at low load and analyze the energy-saving transformation potential of the boiler,the coal combustion characteristics experiment,combustion equipment commissioning and coal blending performance test were carried out.The results show that when design coal or low calorific value coal is used,the low load reheat steam temperature of the boiler is samely greatly low.The’’short combustion characteristics’’of high ash and high volatile coal are one of the main reasons for the low reheat steam temperature of boiler under low load.In order to increase the low load reheat steam temperature,it is recommended to greatly reduce the installation tangent diameter of the nozzle and appropriately adjust the distribution proportion of convective heating area of the superheater and reheater system.