660MW超超临界机组再热汽温620℃非均衡调整的实践与应用

Reheat Steam Temperature of 620℃Disequilibrium Adjustment Practice and Application of 660MW Ultra Supercritical Unit

十里泉发电厂2×660MW高效超超临界抽凝供热型机组,属于华电集团公司首台,该机组再热汽温设计值为620℃,因再热汽温的设计值与受热面管材的允许温度的富余量较小,且受热面允许温度值存在着随压力升高而降低的变化特性关系,对设备运行的可靠性、控制系统的调节性能和运行操作水平提出了更高、更加严格的要求。为解决再热汽温620℃攻关难题,十电集控运行车间经过多方面的研究,创造性地提出"非均衡"调整理念,并以此为根据,通过调整燃尽风、二次风挡板,人为制造烟温偏差,实现烟温与再热器汽温及壁温的相互耦合,为实际的运行操作提供依据和方法,有效减少热偏差,降低因壁温超限对提高再热汽温的制约影响。

2×660MW ultra supercritical extraction condensing heating unit of Shiliquan Power Plant is the first group of Huadian Group Company.The design value of reheat steam temperature of the unit is 620,The surplus quantity between the design temperature of reheat steam temperature and the allowable temperature of heating surface is small,and the allowable temperature of heating surface has a change characteristic with the increase of pressure,so higher and stricter requirements for the reliability of the equipment operation,the regulation performance of the control system and the operation level are put forward.In order to solve the problem of reheat steam temperature at 620 degrees,we have studied in many ways.Finally,we creatively put forward the idea of"non balanced"adjustment.And on this basis,by adjusting the burning wind and the two windshield,we make smoke temperature deviation to achieve the coupling between flue gas temperature and reheater steam temperature and wall temperature,which provides basis and method for actual operation.It can effectively reduce the thermal deviation and reduce the influence of the wall temperature exceeding the limit to improve the temperature of reheat steam temperature.