毕业设计（论文）-关于汽轮机回热系统加热器给水焓升最优分配问题的研究.doc

关于汽轮机回热系统加热器给水焓升最优分配问题的研究
摘要
汽轮机回热系统加热器给水焓升优化分配问题是发电厂热力系统优化的重要组成部分。通过推导出各回热加热器焓升通用表达式,可以指导机组设计和节能改造,有效提高汽轮机运行热经济性。因此研究汽轮机回热系统加热器给水焓升最优分配问题具有重要意义。
文中首先分析了现有衡计算方法的基础上,以火电机组热力系统为研究对象,通过严谨的数学推导,得出了回热系统给水焓升最佳分配的通用表达式。与以往所提出的各种方法相比,该通用表达式考虑了机组的各种实际因素,而且没有对系统进行任何简化,是真正意义上的最优,且具有通用性。针对国产300MW汽轮机回热系统给水焓升分配进行了应用,通过结合具体实例进行编程计算后,说明了从常规热平衡计算方法开始推导并综合考虑了各种实际因素后得出的焓升分配才是真正的最优分配,并对各种实际因素及各加热器焓升逐一进行分析,同时对比了其它分配方法。最后,从分配结果的大致趋势上给出了焓升分配趋势图。
关键词:回热系统;加热器给水焓升;优化分配
Abstract
Optimal distribution of feed-water enthalpy rise for the steam turbine regenerative system is an important part of the optimization of thermodynamic system of power plants. Through deducing the general expressions of all enthalpy rises, the operation and reform in saving energy for steam turbines can be guided, and the economy of steam turbines can be effectively enhanced. Therefore studying the optimal distribution of feed-water enthalpy rise is of great significance.
Firstly, the defects of the existing optimal distribution of feed-water enthalpy rise at home and abroad were analyzed in this paper, and the general expressions of enthalpy rises were given through precise math deduction, which was based on heat balance calculating method. The research object was locked in coal power heating system. Compared with previously various methods, the general expression included all kinds of practical factors. Also, any simplification was not allowed to exist and the system was the real optimal with the widely general expression. Secondly, regenerative system for the domestic 300MW steam turbine was calculated by programming. And the real optimal distribution that was obtained by the energy balance of the thermal system prehensively considered by various practical factors. At the same time, the analysis on all kinds of practical factors and enthalpy rise of each heater were done and other distribution methods were contrasted. Finally, the trend graph of distribution of enthalpy rises was given fr