燃烧烟煤锅炉大比例掺烧褐煤的技术改造

Technical Retrofit of a Bituminous Coal-fired Boiler for Co-firing Large Proportion of Lignite

为了解决燃烧烟煤锅炉大比例掺烧褐煤时磨煤机出力不足及负荷无法提升等问题,提出采用在进磨煤机前的热一次风风道中增设蒸汽换热器来提高一次风风温的方案,以实现对热一次风的二次再热,使一次风风温提高30K以上,满足大比例掺烧褐煤的目的。结果表明:增加蒸汽换热器后褐煤掺烧比例增加15%左右,磨煤机出口温度保证在70℃以下,一次风风率回归到设计值附近。

To solve the problems existing in a bituminous coal-fired boiler when co-firing large proportion of lignite,such as insufficient output of the pulverizer and low load operation,etc.,a retrofit scheme was proposed to increase the primary air temperature by adding a steam heat exchanger in the hot primary air duct before entering the coal mill,thus achieving secondary reheating of the hot primary air,so as to raise the primary air temperature by more than 30 K,in which case,the purpose of co-firing large proportion of lignite could be realized.Results show that the co-firing proportion of lignite could be increased by about 15% after adding the steam heat exchanger,when the output temperature of the coal mill is kept below70℃,and the primary air rate returns to the design value.