燃用褐煤锅炉改烧烟煤时干燥剂的计算及选取

200MW褐煤机组在全改烧省内烟煤时,进行了改前改后的对比性试验,试验中发现,锅炉可满足全烧省内烟煤,锅炉效率基本达到烧褐煤时的设计值,燃烧稳定,未发现结焦,但制粉系统存在磨出口温度高、含氧量高等问题,通过对干燥剂的重新热力计算及选取,确定以“高温炉烟 热风 压力冷风”为合理的干燥方式,并满足制粉系统的防爆要求。

The Calculation and Selection of Drying Agents in Connection with the Change of Fuel for a Boiler from Brown Coal to Bituminous One

Contrast tests were conducted concerning a 200 MW brown coal fired boiler prior to and after its modification to firing bituminous coal of Heilongjiang Province. During the tests it has been found that after a change of coal to the bituminous one the boiler enjoyed a stable combustion and basically attained the same design efficiency as that of the brown coal fired boiler. No severe slag formation has been detected. However, regarding the pulverized coal preparation system there was an excessively high temperature and oxygen content of flue gas at the coal mill outlet. Through a renewed thermodynamic calculation and selection of the drying agent it was decided to adopt a more rational drying mode involving the use of "high temperature boiler flue gas hot air pressurized cooling air". The latter can also meet the explosion proof requirements of the pulverized coal preparation system.