褐煤高温热烟气干燥的调整及改造

Adjustment and Transformation of Lignite Drying Technology with High Temperature Flue Gas

采用大风量吹扫再点火和制定主燃料跳闸逻辑,减少了积粉自燃、爆炸的危险,提高了褐煤干燥运行的安全性。提出了滚筒干燥机入口烟温,出口烟温,氧量等重要参数的调整原则。在完成燃烧器一次风管改造,粉仓电加热改造,以及严格执行系统预暖完成再投煤的基础上,干燥系统实现了连续运行。干燥结果表明,原料煤初始水分越低,滚筒出口块煤和粉仓内粉煤全水分越低,滚筒出口块煤发热量增加幅度越小,粉仓内粉煤发热量还可能随着灰分的增加而降低。要加强对成品煤水分和灰分的控制和运行参数优化,避免出现成品煤过干燥和破坏系统物料平衡。

The schemes including igniting after large air purging and the establishment of master fuel trip logic have been proved helpful to reduce the autoignition and explosion of coal powder, and improve safety operation in lignite drying process. Adjustment principle of several important parameters was proposed, such as inlet flue gas temperature, exit gas temperature,and oxygen. Based on primary air duct reconstruction in burner, electric heating transformation in bunker, and strictly pre-warming before wet lignite drying, continuous operation on drying-system reached. According to the coal analysis, as the total mositure content of wet lignite decreases, the total mositure content of the block coal and pulverized coal also decreases, but the increasing extent of net calorific value of the block coal decreases, and net calorific value of the pulverized coal maybe decreases with the rise of ash content. The total moisture and ash content of product coal should be controlled reasonably, to avoid over-drying and damage the system mass balance.