W火焰锅炉无烟煤煤粉气流着火特性

针对采用缝隙式燃烧器的600 MW超临界W火焰锅炉进行了热态试验研究,着重考察了不同工况下无烟煤煤粉气流的着火特性。试验结果表明,煤粉气流着火特性受燃烧器配风和煤粉浓度影响较为敏感。较低的一次风速可以显著缩短浓相煤粉气流着火距离,在1 m左右可以稳定的着火;二次风应在煤粉气流着火后补入,过大或过小的二次风均容易引起燃烧恶化;无烟煤煤粉气流的燃烧宜采用较高的煤粉浓度,煤粉浓度提高至1.0 kg/kg后浓相煤粉气流的着火更加稳定。控制合适的煤粉气流着火距离对W火焰锅炉运行非常重要,着火延迟距离过大后会引起火焰中心的下移从而容易造成冷灰斗区域的温度过高。

Anthracite ignition characteristics in an arch-fired boiler with slot burners

Experimental studies were conducted on the anthracite ignition characteristics under different conditions in a 600 MW supercritical arch-fired boiler equipped with slot burners.The experimental measurements reveal that the ignition distance of the pulverized coal flows is affected by the air distribution of the burner and pulverized coal concentration.The ignition distance of the fuel-rich flows become remarkably shorter under the low primary velocity.The fuel-rich flows could be ignited at about 1 meter away from the burner.The secondary air should be added into the primary flows after being ignited and it is ease for the excess or deficiency of secondary air to cause the deterioration of combustion.A higher concentration of pulverized coal is favorable for anthracite ignition.Ignition of the fuel-rich flows become more stable after rising the concentration of pulverized coal to 1.0 kg/kg.Appropriate ignition distance of pulverized coal flows is very important to the operation of arch-fired boilers.The delayed ignition distance of pulverized coal could lower the flame center and cause the high temperature of the hopper region.