Research and Development of Hot Primary Air Heater for Coal-Fired Boilers in Power Plant

The reasons of introducing cold air into pulverizer are analyzed for boilers with large capacity and high parameters. The temperature rises of the exhaust gas are calculated when varying the amount of the cold air. The hot primary air heater, a new technology, is developed to eliminate the cold air from the pulverized coal system. The applications, advantages and disadvantages are introduced in detail for the new device and system. It is concluded that introducing cold air into pulverizer is one of the major factors that causes the exhaust gas temperature of boilers with large capacity to be high. The amount of the cold air could be reduced signif icantly, even to zero in some cases by adopting the hot primary air heater, which drops the exhaust gas temperature of the boiler effectively. The hot primary air heater, which could play part roles of the steam-air heater or the hot air recirculation system, could also be used to adjust the exhaust gas temperature within the range of 20 ℃ by controlling the flow rate of the cooling medium. Moreover, the startup period of the steam-air heater or the hot air recirculation system will be shortened, which is a unique advantage of the hot primary air heater among the measures to drop the exhaust gas temperature.

某电厂中间贮仓式制粉系统爆炸原因分析

对某发电厂中间贮仓式制粉系统爆炸原因进行了分析,认为细粉分离器进口管磨穿处积粉自燃、排粉机出口风压突降、调节不当使制粉系统内气流停滞甚至倒流,引发了系统积尘爆炸。对此,采取防磨防爆等相应措施后,制粉系统运行良好,未再出现类似事故。

75t/h乏气送粉煤粉锅炉低氮燃烧改造

针对某电厂1#锅炉NO_x排放量过高、炉膛出口烟气温度偏差较大以及水冷壁结焦问题,采用低氧燃烧、增加燃尽风、深度空气分级等技术,对某电厂1#锅炉实施改造,改造后进行冷态试验和燃烧试验调整。改造后,经过配风试验,假想切圆达到设计要求,其他各参数也基本符合设计要求。1#炉改造前的NO_x排放值是700~850 mg/m^3(标态、干基、6%O_2),改造后降低到300 mg/m^3(标态、干基、6%O_2)以下,脱硝效率达到55%。锅炉的炉膛出口烟气温度偏差,也从改造前的大于100℃降低至50℃以下。经过持续的观察,炉膛水冷壁基本光滑无结焦,喷口附近有少量松散浮灰,可以轻易打掉,总的来说,锅炉改造后,达到了改造前的预想结果,改造是比较成功的。