1000MW双切圆燃烧锅炉干湿态转换过程中水冷壁温度控制

针对超超临界双切圆锅炉干湿态转换过程中的水冷壁温度偏差大、超温的问题,采取了三个阶段的控制措施:干湿态转换前,优先投入上层磨煤机运行,提高锅炉压力和给水温度;转态过程中,维持合适的水煤比以及较低的中间点过热度;锅炉正常运行时,尽量提高炉膛火焰中心高度,使炉膛热负荷分布更加均匀,调整一、二次风配风方式,降低"热角"区温度。此外,取消了超温管的节流孔圈,增大质量流速。通过以上调整方法,有效缓解了干湿态转换过程中水冷壁超温问题,改善了水冷壁的运行工况。

Water-Wall Temperature Control of a 1 000 MW Dual Circle Tangential Firing Boiler during Wet-Dry Transferring Period

Aiming at the problems of water-wall overheating and large temperature deviations of the ultra-supercritical dual tangential circle boiler in the wet-dry transferring period, a three-stage control measure is adopted. Prior to the wet-dry transferring, the upper mills are put into operation to increase the boiler pressure and the feeding water temperature. During the transferring, an appropriate water/coal ratio and a superheating degree are settled and maintained. During the routine operation, the flame height should be kept as high as possible to improve the heat uniformity and the primary and secondary air distributions are adjusted to lower the "hot corner" temperature. In addition, the orifice plates of the overheated water-wall tubes are removed to increase the mass velocity. The results show that this measure has effectively alleviated the overheating of the water-wall and improved the water-wall operation conditions.