基于Aspen Plus的超超临界循环流化床锅炉的性能计算及分析

循环流化床发电技术以其特有的优势,得到了迅速发展和广泛应用。近年来,为了实现超低排放和超低能耗,大型化与高参数化的超超临界循环流化床锅炉(CFB)的设计研究成为我国洁净煤发电技术的主要发展方向。目前超超临界发电机组的基础理论与设计计算还不完善,因此对于其运行模拟以及在运行条件变化时锅炉主要参数的预测尤为重要。Aspen Plus能够对复杂的化工过程进行精细的稳态模拟和流程设计,基于Aspen Plus软件提供的内置模块和FORTRAN编译器的外部子程序,建立了660 MW超超临界CFB锅炉燃烧室煤解耦燃烧过程模拟模型,主要包括煤的等效热解模型、简约解耦燃烧模型、分离器、外置床及尾部烟道低温过热器、低温再热器模型。依据所建立的稳态模型,可模拟计算660 MW超超临界循环流化床锅炉在满负荷工况(B-MCR)下锅炉性能,得到其各处主要温度的计算结果,分析燃烧室中密相区和疏相区的气体组分浓度,并且预测了循环流化床燃烧室运行参数一次风配比对密相区组分CO2、CO和SO2浓度的影响以及过量空气系数对排烟气体组分SO2、SO3、NO和N2O浓度的影响。同时,利用该模型计算了过量空气系数和改变一次返料比例对中温过热器、低温过热器出口汽温和低温再热器、省煤器出口烟温的影响。在660 MW超超临界循环流化床锅炉的设计研究上,为降低污染物排放、减少锅炉热损失和提高锅炉效率提供了参考依据。

Performance calculation and analysis of ultra-supercritical circulatingfluidized bed boiler based on Aspen Plus

Circulating fluidized bed(CFB)power generation technology has been rapidly developed and widely used due to its unique advantages.In recent years,in order to achieve the goals of ultra-low emission and ultra-low energy consumption,the design and research of large-scale and high-parameter ultra-supercritical CFB boiler)has become the main development direction of clean coal power generation technology in China.At present,the basic theory and design calculations of ultra-supercritical generating units are not perfect,so it is particularly important for the simulation of its operation and the prediction of the main parameters of the boiler when the operating conditions change.Aspen Plus can perform sophisticated steady-state simulation and process design of complex chemical processes.Based on the built-in modules provided by the Aspen Plus software and the external subroutines of the FORTRAN compiler,the simulation model of coal decoupled combustion process in combustion chamber of a 660 MW ultra-supercritical CFB boiler was established.The process simulation model mainly includes the equivalent pyrolysis model of coal,simplified decoupled combustion model,separator,external bed and tail flue low temperature superheater and low temperature reheater model.Based on the established steady-state model,the performance of the 660 MW ultra-supercritical circulating fluidized bed boiler under full-load operating conditions(B-MCR)was simulated and calculated.The calculation results of its main temperature can be obtained,the gas component concentrations in the dense phase zone can be analyzed and the sparse phase zone in the combustion chamber,and the influence of the primary air ratio of the CFB combustion chamber operating parameters on the concentration of CO 2,CO and SO 2 in the dense phase zone and the influence of excess air coefficient on the concentration of the exhaust gas components SO 2,SO 3,NO and N 2 O can be successfully predicted.At the same time,the model was used to calculate the effect of excess air coefficient and changing the ratio of primary return material on the outlet steam temperature of medium temperature superheater,low temperature superheater,and the temperature of flue gas at low temperature reheater and economizer.The design and research of the 660 MW ultra-supercritical circulating fluidized bed boiler provides a reference basis for reducing pollutant emissions,reducing boiler heat loss and improving boiler efficiency.