为研究BEST系统和常规热力系统的区别，基于某超超临界1 000 MW二次再热机组的设计计算，使用EBSILON软件建立完整热力系统模型，然后从焓升分配，回热级数选择，再热压力优化，小汽轮机效率的影响等几个方面对比两种系统的异同点，并从热力学角度对其加以解释和说明。结果显示BEST系统的焓升分配更为均匀，回热级数选择需要考虑给水泵功率需求，最佳再热压力相对于常规系统压力更高，对小汽轮机效率的敏感性只有常规系统的一半。

In order to study the differences between BEST and conventional thermal systems,a complete thermodynamic system model was established based on the design and calculation of a supercritical 1 000 MW double reheat unit.Then,the similarities and differences between the two systems were studied form following aspects,such as the enthalpy rise distribution,heat recovery series selection,and the impact of feedwater pump turbine efficiency,and explained from the thermodynamic point of view.The results showed that the enthalpy rise distribution of the BEST system is more uniform.The choice of the regenerative series of BEST system requires consideration of the feedwater pump power demand.The optimum reheat pressure of BEST system is higher than that of the conventional system,and the efficiency of BEST system is only half sensitive to the efficiency of the steam turbine compared with the conventional system.

TM621