火电机组冷端系统运行优化的研究

发布时间：2018-09-11 10:16

【摘要】：汽轮机冷端系统是火电机组的重要组成部分,维持机组冷端处于最佳运行状态对提高机组效率具有非常大的工程意义,是保证机组经济性运行的重要措施。而凝汽器真空对机组能耗和发电效率产生重要影响,为保证机组运行的效益,往往需要凝汽器真空维持在最佳值,鉴于冷端系统对机组运行的重要作用,对冷端系统运行优化的研究十分重要。因此,本文进行了以下工作。首先,结合换热过程以及经验公式对凝汽器传热系数影响因素进行总结,基于相似理论获得标定工况的无量纲数,并利用变工况数据确定了计算该机组凝汽器传热系数的kc—M模型。结果表明,此计算模型避免了经验公式对特定凝汽器修正带来的计算偏差,也避免了试验方法不能获得所有可能工况的局限性,能够较好的描述凝汽器换热强度,与试验数据相比相对误差不超过1.41%,满足工程应用的要求。然后,根据机组运行调度的实际情况,将凝汽器最佳真空进行重新定义,提出了定功率条件下,汽轮发电机组供电热效率最大的最佳真空确定标准。另外,针对此最佳真空指标,利用等效焓降法获得凝汽器压力—机组发电功率计算模型,并据此建立了机组发电功率一定时的热耗量与凝汽器压力计算模型。最后,利用本文凝汽器真空优化模型,对实际机组循环水泵进行优化,确定优化方案。结果表明,循环水泵进行优化调度后,与各工况全部采用A、B(高速)、C循环水泵并联运行方式相比,机组供电热耗率最多可减少151.8 kJ/(k W?h);与各工况全部采用A、C循环水泵并联运行方式相比,机组供电热耗率最多可减少97.5 kJ/(kW?h)。经过优化后的机组可以收到较为可观的机组供电热耗率减少量。
[Abstract]:The cold end system of steam turbine is an important part of thermal power unit. It is of great engineering significance to improve the efficiency of the unit to maintain the optimal operation state of the unit cold end. It is also an important measure to ensure the economic operation of the unit. The condenser vacuum has an important effect on the energy consumption and generation efficiency of the unit. In order to ensure the efficiency of the unit operation, it is often necessary to maintain the condenser vacuum at the optimum value, in view of the important role of the cold end system on the unit operation. It is very important to study the operation optimization of cold end system. Therefore, this paper does the following work. Firstly, combined with the heat transfer process and empirical formula, the factors affecting the heat transfer coefficient of the condenser are summarized, and the dimensionless number of the calibrated working conditions is obtained based on the similarity theory. The kc-M model for calculating the heat transfer coefficient of the condenser is established by using the variable working condition data. The results show that the calculation model avoids the error caused by the empirical formula and the limitation that the test method can not get all the possible working conditions, and it can describe the heat transfer intensity of the condenser well. Compared with the test data, the relative error is not more than 1.41, which meets the requirements of engineering application. Then, according to the actual condition of unit operation and dispatching, the optimal vacuum of condenser is redefined, and the optimal vacuum determination standard for the maximum power supply efficiency of turbine generator is put forward under the condition of constant power. In addition, the equivalent enthalpy drop method is used to obtain the calculation model of condenser pressure-generating power, and the calculation model of heat consumption and condenser pressure is established according to the optimal vacuum index. Finally, the condenser vacuum optimization model is used to optimize the circulating water pump and determine the optimization scheme. The results show that, after optimal dispatching of circulating water pump, compared with the parallel operation mode of Agna B (high speed) C circulating water pump, The heat consumption rate of the unit can be reduced by 151.8 kJ/ (k WH) at most, and the heat consumption rate of the unit can be reduced by 97.5 kJ/ (kW?h) as compared with the parallel operation mode of the AGC circulating water pump under all working conditions. The optimized unit can receive a considerable reduction in the power supply heat consumption rate.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM621

【参考文献】