链条锅炉给煤装置的改造及应用

扬州石化35t／h链条锅炉由于存在着煤种变化频繁以及现有分层布煤机构设计缺陷，不能适应各煤种热值及颗粒度的变化，导致锅炉燃烧不充分。为此，对落煤料仓、分层给煤装置和垄形平煤给煤装置进行改造。改造后，锅炉落煤料仓给煤闸板两边卡堵大煤块的现象基本消除，下煤顺畅；改进后的筛分板，其炉排煤层分层效果突出。大小煤块分布清晰，煤层疏松，过风阻力小；垄形平煤给煤机构的改造，使分层后的煤层形成平整垄形，平整煤层，透风均匀，耗风量降低，燃烧所需过剩空气“系数控制在较低的水平；垄形煤层使煤层和空气接触面积增加。燃烧工况好．达到了半沸腾燃烧效果，火床短、火焰稳定，炉渣含碳量降低。改造前后的数据比较显示，改造取得了较好的经济效益，年节约燃料费用约45万元，链条炉排锅炉对煤种的适应性增强，热效率可提高3个百分点。

Upgrade of Coal Feeding System of Chain Grate Boiler

As it frequently switched different coal products and there was a design defect in the layered coal distributor,Yangzi Petrochemical Company＇s 35t/h chain-grate boiler was unable to adapt to the changes in the heat value and granularity of feedstock coal,leading to incomplete combustion in the boiler.Technicians therefore modified the coal bin,the layer-by-layer coal charging unit and the ridgy coal leveling and feeding unit.After the modification,coal feeding became smooth and block coal was basically no longer stuck at the edges of the coal feeding gate of the coal bin.The fire grate of the modified screening plate had excellent coalbed lamination effect with small and large lumps of coal distributed clearly and the combed being spongy with small ventilation resistance.After the modification of the ridgy coal leveling and feeding mechanism,the laminated coalbed became a level ridge with even ventilation,reducing the need for air.The excess air coeffi- cient for combustion remained low.Ridgy coalbed has increased contact with the air and therefore has better conditions for combustion （achieving semi-fluidized combustion）An addition,the fire bed is shorter,the fire is stable and the carbon content of the slag is low.The comparison between data prior to and after these modi- fications shows that the modifications yielded good economic results.The costs of fuel dropped by around 450,000 yuan per year, the adaptability of the chain-grate boiler to different coal products improved and the thermal efficiency of the boiler increased by 3%.