关键词: 火力发电, 高水分褐煤, 中速磨煤机, 燃烧优化

Abstract: This paper focuses on the issues of the difficult dust control, spontaneous combustion of accumulated powder, explosions of coal pulverizing system and steam dryer, and coal bunker blockage caused by the steam drying processing of high-moisture(60%~63%), high- volatile and low calorific value lignite in Shenhua Guohua(Indonesia) Sue Power Generation. Through the test on increasing the raw coal moisture contents at the steam dryer outlet, the issues are thoroughly solved when the moisture contents are raised from about 40% to 52%~55%. However, the increase of raw coal moisture contents causes the insufficient pulverizer output, coal powder conveying pipeline blockage and boiler instable combustion problems. Through the pulverizer and combustion optimization tests, the boiler can fire the high- moisture(52%~55%) lignite successfully. Moreover, the optimization tests also exhibit that there will be no blockage when the pulverizer outlet temperature is over 57 ℃, and other problems, such as low primary air temperature and insufficient combustion, will also get controlled as the primary air ratio is under 45%. Consequently, the boiler combustion efficiency reaches as high as 90%, which realizes the goal of safe, stable and economic operation when the boiler with medium-speed pulverizer fires high-moisture lignite.

Key words: high-moisture lignite, medium-speed mill, combustion optimization