超临界600 MW循环流化床(circulating fluidized bed, CFB)机组具有更复杂的锅炉特性,因此超临界循环流化床机组的控制系统对于锅炉的安全与稳定运行具有重要的意义,其中控制策略是控制系统的核心与难点。CFB 炉膛内存储的即燃碳燃烧是CFB锅炉燃烧发热量的主导因素,是造成CFB锅炉燃烧比煤粉炉滞后的主要原因。文中通过机理分析构造 CFB 锅炉的即燃碳模型,估算了某台600 MW超临界CFB锅炉炉膛内即燃碳量。将该状态量应用于锅炉的给煤控制、给水控制、送风控制系统中,提高了机组负荷的动态响应特性,稳定机组的主蒸汽压力、主蒸汽温度等参数。实践验证了所提控制策略和所构造模型的有效性。
The 600 MW supercritical circulating fluidized bed(CFB) unit has a significant character with more complex boiler properties. So the control system of supercritical CFB unit has important significance for the safe and stable for the boiler,and the control strategy is the core and difficulty of control system. Burning carbon in the CFB furnace is the dominant factor. It is the main reason causing more combustion lag than the pulverized coal fired boiler. This paper analyzed the mechanism structure model of burning carbon in the boiler and estimated the burning carbon storage capacity in a 600 MW supercritical CFB boiler furnace. The state quantity was applied in the boiler for the coal control, the feed water control, and the wind control. It improves the dynamic response characteristics of load, and the same time can stable the main steam pressure and the main steam temperature. The practice proves the effectiveness of the proposed control strategies and the structure models.