烟煤锅炉两种方式掺烧褐煤的工程应用

Application study on boiler performance when the firing bituminous coal mixed with lignite in two measures

从掺烧褐煤对制粉系统、燃烧过程以及排烟温度3个方面的影响对比分析了炉外掺烧方式与炉内掺烧方式的差异,并采用现场对比试验的实测结果,对分析结论进行了验证。从中得出主要结论:(1)炉内掺烧方式在制粉系统安全性、预防炉内结渣以及降低制粉系统电耗等方面优于炉外掺烧方式;(2)对于某具体褐煤,主煤的含水质量分数存在一个临界值。当主煤含水质量分数大于该临界值时,炉内掺烧方式下的锅炉排烟温度低于炉外掺烧方式,其经济性优于后者;(3)对于大多数烟煤锅炉,其主煤实际含水质量分数通常大于或接近其临界水分值,炉内掺烧方式的运行经济性优于炉外掺烧方式。因此,在条件许可的情况下,电厂应尽可能地采用炉内掺烧方式掺烧褐煤,在褐煤含水质量分数小于35%,主煤含水质量分数大于10%时尤应如此。

The difference of the two measures when firing bituminous coal mixed with lignite inside and outside the furnace was analyzed from the affects to milling system and combustion process and flue gas temperature, and the analyzed conclusions were validated based on the practical text data, the main conclusions were obtained as follows： （ 1 ） the method of firing mixed coal inside the furnace is better than that outside the furnace from the security and electricity consumption of milling system and preventing furnace slagging; （2） for a certain lignite, there is a critical value of total water for bituminous coal, when the total water of bituminous coal is bigger than the critical value, the efficiency of firing bituminous coal mixed with lignite inside the furnace is better than that outside the furnace, and the economy is also better; （3）for most boilers that firing soft coal, the total water of bituminous coal is bigger than or approach to the critical value, so power plants is suggested to use the measure of firing bituminous coal mixed with lignite inside the furnace, especially when the total water of bituminous coal is more than 10% and the total water of lignite is less than 35%.