W型火焰旋流燃烧锅炉混煤着火试验研究

在某电厂W型火焰锅炉上研究贫煤、烟煤和无烟煤混煤的着火特性。在燃烧器附近进行煤粉气流温度测量，分析了掺烧烟煤前后燃烧器轴向煤粉气流温度的变化，分析了贫煤和无烟煤不同比例时燃烧器轴向煤粉气流温度的变化，比较了侧墙燃烧器和炉膛中部燃烧器轴向煤粉气流温度的变化。结果发现，混煤的煤粉气流分两次进行燃烧。首先燃烧的是易着火的烟煤，当烟煤逐渐燃尽后煤粉气流温度有所降低，随后着火温度高的无烟煤才开始燃烧，煤粉气流温度再次上升。当无烟煤和贫煤混煤掺烧时，随着无烟煤比例的提高，煤粉气流温度降低，着火距离逐渐延长。炉膛壁温和漏风降低了煤粉气流的温度，使得煤粉燃烧需要更多的热量，使得靠近侧墙的燃烧器着火推迟。

Experimental Study on Ignition of Blended Coal in W-Flame Boiler with Swirl Burners

The ignition characteristics of coal blends with lean coal, anthracite and bituminous coal are studied on a W-flame boiler in a power plant. The temperature of pulverized coal air is measured near the burners. Then the variation of axial pulverized coal airflow temperature is analyzed before and after blending the bituminous coal. The axial pulverized coal airflow temperature with respect to different proportions of the lean coal and the anthracite is also analyzed. Finally the variation of axial pulverized coal airflow temperature between side wall burner and middle burner is compared. It is found that the blended coal powder are burned twice. The lean coal which is easier to be ignited burns first. When the bituminous coal gradually burns out, the temperature of the pulverized coal airflow starts to drop down a little. Then after the anthracite with higher ignition temperature begins to burn, the pulverized coal airflow temperature rises again. If the lean coal is blended with anthracite, the temperature of pulverized coal will decrease and the ignition distance will be extended gradually with the increase of anthracite ratio. The furnace wall and mild air leakage cause the temperature decrease of the pulverized coal airflow such that more heat will be needed for the pulverized coal combustion, which eventually delays the ignition of the burner near the side wall.