ZHOU Xu;ZHOU Yanjun;LI Weicheng;LU Jiayi;LIU Xinglei;DENG Qigang;LI Yinlong;YANG Dong;

• 1:School of Energy and Power Engineering
• 2:Xi'an Jiaotong University
• 3:Key Laboratory for Clean Combustion and Flue Gas Purification of Sichuan Province

Abstract：

It is important to ensure the heating surfacesafety of ultra-supercriticalcirculating fluidized bed(CFB)boiler under electricity failure. The factors that affect the safety of heating surfaces of a supercritical circulating fluidized bed boiler after a power outage accidentwere analyzed. The transient flow heat transfer calculation model for the boiler heating surfaces was established based on the conservation of mass, momentum, energy, and the heat storage equation of the tube-wall. A program for calculating the dynamic characteristics of the boiler steam water systemwas also developed, which can calculate the variation of the working fluid temperature and tube-wall temperature with timeon the heating surface of a boiler under power loss conditions.The result shows that the high-pressure bypass valve needs to exhaust steam at a flow rate of 40% BMCR, with a minimum critical time of 110s for exhaustwhen the safety of the boilerheating surface is ensured. Meanwhile, the inlet of the economizer needs to be replenished with water at a flow rate of 140 t/h. Theworking fluid and tube-wall temperature of the water wall, low-temperature superheater, medium temperature superheater, and high-temperature superheater rise first and then decrease over timeunder this condition. The highest value of tube-wall temperature is lower than the allowable temperature for heating surface material. The measures proposed can ensure the safety of heating surfaces of the ultra-supercritical CFB boiler under electricity failure, solve the problem of overheating of the heating surface after the power loss accident of the CFB boiler, which provides guidance for the operation of the power plant.

Key Words： circulating fluidized bed boiler;electricity failure;heating surfaces;shigh pressure bypass valve

Abstract:

Keywords:

Foundation: 国家重点研发计划资助项目(2022YFB100303)

Authors: ZHOU Xu;ZHOU Yanjun;LI Weicheng;LU Jiayi;LIU Xinglei;DENG Qigang;LI Yinlong;YANG Dong;

DOI: 10.13226/j.issn.1006-6772.23072101

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