基于受热面蒸汽侧氧化皮生成与剥落机理的优化控制

Optimal Control Based on the Formation and Peeling Mechanism of Oxygen Skin on the Steam Side of the Heating Surface

为减缓和预防超超临界机组蒸汽侧氧化皮生成和剥落对机组产生的危害,从受热面蒸汽侧氧化皮生成和剥落的原理出发,结合机组运行的特点,详细阐述了蒸汽氧化皮生成、剥落的机理及危害,着重分析了机组启停机和正常运行期间的可控因素,并从安全性和经济性角度出发,制订了机组管壁温度管控、蒸汽温度管控、减温水管控、机组燃烧调整、机组启停机操作指导、机组停机后焖炉管理等措施。通过措施实施后的效果检验,发现相关措施有利于抑制蒸汽侧氧化皮的生成和剥落,实现机组全负荷段的再热汽温620℃,带来较大经济效益,实现机组的安全和经济运行。

In order to slow down and prevent the generation and spalling of steam-side oxide scale on ultra-supercritical units,the principle of steam-side scale formation and spalling on the heating surface is introduced in this paper with comprehensive consideration of the characteristics of unit operation to elaborate the steam scale formation,the mechanism and hazards of spalling.The controllable factors during the start-up,shutdown and normal operation of the unit are analyzed.From the perspective of safety and economy,the counter measures are formulated including unit wall temperature control,steam temperature control,desuperheating water control,unit combustion adjustments,unit start-up and shutdown operation guidance and oven management after unit shutdown,etc.Through the effect test after the implementation of the measures,it is found that the relevant measures are conducive to suppressing the formation and spalling of scale on the steam side,and realizing the reheated steam temperature at the full load section 620 ℃,which brings great economic benefits and realizes the safe and economic operation of the unit.