【摘要】：汽輪機(jī)冷端系統(tǒng)是火電機(jī)組的重要組成部分,維持機(jī)組冷端處于最佳運(yùn)行狀態(tài)對(duì)提高機(jī)組效率具有非常大的工程意義,是保證機(jī)組經(jīng)濟(jì)性運(yùn)行的重要措施。而凝汽器真空對(duì)機(jī)組能耗和發(fā)電效率產(chǎn)生重要影響,為保證機(jī)組運(yùn)行的效益,往往需要凝汽器真空維持在最佳值,鑒于冷端系統(tǒng)對(duì)機(jī)組運(yùn)行的重要作用,對(duì)冷端系統(tǒng)運(yùn)行優(yōu)化的研究十分重要。因此,本文進(jìn)行了以下工作。首先,結(jié)合換熱過(guò)程以及經(jīng)驗(yàn)公式對(duì)凝汽器傳熱系數(shù)影響因素進(jìn)行總結(jié),基于相似理論獲得標(biāo)定工況的無(wú)量綱數(shù),并利用變工況數(shù)據(jù)確定了計(jì)算該機(jī)組凝汽器傳熱系數(shù)的kc—M模型。結(jié)果表明,此計(jì)算模型避免了經(jīng)驗(yàn)公式對(duì)特定凝汽器修正帶來(lái)的計(jì)算偏差,也避免了試驗(yàn)方法不能獲得所有可能工況的局限性,能夠較好的描述凝汽器換熱強(qiáng)度,與試驗(yàn)數(shù)據(jù)相比相對(duì)誤差不超過(guò)1.41%,滿足工程應(yīng)用的要求。然后,根據(jù)機(jī)組運(yùn)行調(diào)度的實(shí)際情況,將凝汽器最佳真空進(jìn)行重新定義,提出了定功率條件下,汽輪發(fā)電機(jī)組供電熱效率最大的最佳真空確定標(biāo)準(zhǔn)。另外,針對(duì)此最佳真空指標(biāo),利用等效焓降法獲得凝汽器壓力—機(jī)組發(fā)電功率計(jì)算模型,并據(jù)此建立了機(jī)組發(fā)電功率一定時(shí)的熱耗量與凝汽器壓力計(jì)算模型。最后,利用本文凝汽器真空優(yōu)化模型,對(duì)實(shí)際機(jī)組循環(huán)水泵進(jìn)行優(yōu)化,確定優(yōu)化方案。結(jié)果表明,循環(huán)水泵進(jìn)行優(yōu)化調(diào)度后,與各工況全部采用A、B(高速)、C循環(huán)水泵并聯(lián)運(yùn)行方式相比,機(jī)組供電熱耗率最多可減少151.8 kJ/(k W?h);與各工況全部采用A、C循環(huán)水泵并聯(lián)運(yùn)行方式相比,機(jī)組供電熱耗率最多可減少97.5 kJ/(kW?h)。經(jīng)過(guò)優(yōu)化后的機(jī)組可以收到較為可觀的機(jī)組供電熱耗率減少量。
[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.
【學(xué)位授予單位】：上海電力學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TM621

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本文編號(hào)：2236402