不同干燥程度胜利褐煤燃烧与自燃特性

摘要

In order to investigate the change of combustion and self-ignition characteristics of high moisture lignite under different drying degrees,a one-dimensional flame combustion furnace,a pulverized coal ignition temperature examining furnace and a coal self-ignition analyzing apparatus were used to test the combustion performance of Shengli lignite.Results show that the ignition temperature decreases with the increase of the drying degree,while increases with the rising of the air/coal ratio.The fineness of pulverized coal will also affect the ignition temperature.When burning with the drying lignite,a higher primary air rate should be adopted to improve the safety of coal pulverizing system.Shengli lignite raw coal and the dried samples are very easy to be burn-out,and the burn-out rates are above 99.4％.The change of moisture has little effect on the burn-out rate.The suggested operational oxygen supply is approximate 3.5％ for burning the Shengli lignite and its 20％ moisture drying lignite.The lignite with deeper drying degree and smaller particle size is easier to be self-ignition.The excessive drying with the moisture content less than 20％ will bring higher risk of self-ignition.%为了探究高水分褐煤干燥后的燃烧与自燃特性变化,采用一维火焰炉、煤粉着火炉以及自燃试验台对不同干燥程度的胜利褐煤进行了试验研究.试验结果表明,试验样品的着火温度随着干燥程度的增加而降低,随着风煤比的增加而增加,煤粉细度同样会对着火温度产生影响.在燃用干燥褐煤过程中宜采用较高一次风率以提高制粉系统的安全性.胜利褐煤及其干燥褐煤均属于极易燃尽煤种,燃尽率均在99.4％以上,水分的变化对燃尽率影响不大.建议胜利褐煤与20％水分干燥褐煤的运行氧含量控制在3.5％左右.随着干燥程度的加深和粒径的减小,褐煤越容易自燃.胜利褐煤干燥到20％以下可能有自燃的风险.