超临界机组直流锅炉过热器吸热量动态仿真

摘要

为研究超临界机组直流锅炉过热器调峰过程热力特性及安全性,基于MATLAB/Simulink仿真平台对超临界600 MW机组直流锅炉建立模型并进行数值仿真,分析了锅炉在35％～100％最大连续蒸发量时,过热器吸热量动态特性.研究结果表明:随着锅炉蒸发量增大,炉膛出口和后屏过热器出口烟气温度及对流过热器出口蒸汽温度逐渐升高,而对流过热器出口烟气温度趋于稳定;对流过热器对流吸热量增速最快,变化幅度最大,而对流过热器辐射吸热量相对较小;过热器附加受热面对流吸热量大于辐射吸热量,两侧水冷壁受热面吸热量大于炉顶受热面吸热量;对流过热器区域附加受热面两侧水冷壁对流吸热量最大,炉顶受热面吸收的炉膛辐射热量最小,与后屏过热器区域附加受热面相比,对流吸热量远大于辐射吸热量.%To study the thermodynamic and security characteristics of the super heater in supercritical oncethrough boilers during peak adjustment process,this paper establishes a model for a supercritical 600 MW once-through boiler and carries out the numerical simulation,by using the MATLAB/Simulink platform.The dynamic characteristics of heat absorption of the super heater were studied under conditions with BMCR of 35％ to 100％.The results show that,with an increase in the boiler load,the flue gas temperature at the furnace outlet and the screen-type super-heater outlet,and the steam temperature at the convective superheater outlet increased steadily,while the flue gas temperature at the convective superheater outlet tended to be stable.The convection heat absorption of the convection super-heater was on fastest-growing,while the radiation heat absorption of the convection super-heater was in a relatively minimum value.The convection heat absorption was greater than the radiation heat absorption in additional heating surface,and the heat absorption of the water wall was greater than that of the roof super-heater.Compared with the additional heating surface of screen-type super-heater,the convection heat absorption of the additional heating surface of the convection super-heater was much higher than the radiation heat absorption.