1000MW超超临界锅炉中间点温度和汽温控制

Temperature at Intermediate Points of 1000MW Ultra-supercritical Boilers and their Steam Temperature Control

研究了国内2类不同型式的1000 MW超超临界锅炉的中间点温度控制、主蒸汽和再热蒸汽的汽温特性、各受热面的吸热比例和煤质变化对水煤比控制的影响等问题。结果表明:蒸汽参数基本相同的1000 MW超超临界锅炉,虽然采用了不同的水冷壁结构形式、不同的受热面布置以及不同的汽温调节方式,但反映运行特性的关键技术参数的控制值基本相同;过热汽温变化特性主要表现为辐射特性;再热汽温特性主要表现为对流特性;水冷壁吸热变化对中间点温度和汽温控制起主导作用;分隔屏对汽温特性起重要作用。

Utilizing key technical data of uhra-supercritical boilers, the temperature control of intermediate points of 2 types of 1000 MW ultra-supercritical boilers in this country are being studied, together with the characteristics of their fresh and reheat steam temperature, the endothermal rate of their heat delivery surfaces and the effect of changing coal quality on the control of water to coal ratio etc. The important conclusions obtained are： 1000MW ultra-supercritical boilers, which have basically the same steam parameters, but with water cooled walls employing different techniques and different arrangement of heat delivery surfaces, as well as different ways of steam temperature control, all fundamentally have the same key parametric quantities to reflect operational behavior; characteristics of superheated steam temperature variation manifest themselves as characteristics of radiation and those of reheat steam temperature as the characteristics of convection; variations in heat absorbed by the water cooled walls play adecisive role in the control of temperatures of intermediate points as well as that of steam; division panels remarkably affect the temperature characteristics of steam.