700℃超超临界一次再热П型锅炉水动力特性及壁温分布规律研究

Hydrodynamic characteristics and wall temperature distribution law of a 700 ℃ ultra-supercritical single reheat П type boiler

为了掌握700℃超超临界机组锅炉水动力特性和壁温分布规律,以某600MW,35MPa/700℃/720℃超超临界一次再热П型锅炉为例,采用通用水动力计算方法对700℃超超临界机组锅炉的水动力特性和壁温分布规律进行了数值计算和分析。结果表明,随着高度的增加,水冷壁管内工质温度基本呈线性增加,管壁壁温也随之升高,换热温差沿程变化不大,大比热容区流体换热性能良好,有效地抑制了高热负荷区域壁温的峰值。螺旋管圈水冷壁能够有效地控制700℃超超临界机组锅炉水冷壁的壁温偏差。但是,由于700℃锅炉工作参数的提升,水冷壁出口壁温仍然高达520℃左右,这对锅炉水冷壁材料和锅炉的实际运行均提出了更高的要求。

To master the hydrodynamic characteristics and wall temperature distribution law of 700℃ ultra supercritical unit boiler's hydrodynamic characteristics,this paper takes a 600 MW,35 MPa/700℃/720℃ ultra supercritical unit with single reheat II type boiler as an example to carry out numerical calculation by universal hydrodynamic calculation method.The results show that,along the wall height direction,the working fluid temperature increases linearly,the wall temperature increases correspondingly,while the heat transfer temperature has little change.The good heat transfer performance of the fluid in the large specific heat region effectively inhibits the peak value of the wall temperature in the high heat load region.Using coiled water wall can control the wall temperature deviation effectively.However,due to the increase of working parameters of the 700℃ ultrasupercritical boiler,the outlet wall temperature of the water wall is still as high as 520℃,which puts forward higher requirements for boiler water wall materials and the actual operation of boiler.