电站低压省煤器热经济性分析

发布时间：2018-07-06 12:30

本文选题：热力系统 + 热经济性　；参考：《重庆大学》2014年硕士论文

【摘要】：随着我国经济发展，与能源与环境之间的矛盾日益突出，，火电机组的节能减排成为一个备受关注的问题。为了更好地实现节能减排，国内已建电厂及新设计火电厂工程中，有很多项目采用低压省煤器系统进行烟气余热回收。由于计算方法的差异性，导致对烟气余热回收利用的经济性评价一直存在争议。在这种背景下，急需找到锅炉排烟余热利用经济性的合理评价方法，提高排烟余热的能量转换效率，进一步降低发电能耗。烟气余热回收利用，属于外部热量利用于系统，可以通过循环函数法给以定量分析。本文基于循环函数法，从反平衡的角度，建立了局部定量计算完整的数学模型。把这些模型应用在补水方式、凝结水过冷度等局部定量分析中，分别结合某300MW亚临界机组和某1000MW超超临界机组进行实例计算分析。结合某300MW亚临界机组，将循环函数法的定量计算模型应用在低压省煤器的热经济性分析中，研究了低压省煤器的运行特性以及最佳安装位置。主要研究成果如下： ①最后单元进水系数即为系统不可逆性的反映，减小最后单元进水系数和提高循环吸热量，都可以提高机组的效率。循环函数法的定量计算模型具有概念清晰、通用性强、便于计算机程序化等特点。 ②建立了低压省煤器优化运行数学模型，得到了最优水流量，在额定工况下，水流量为69.2kg/s时，机组效率相对增量最大，为0.722%。通过对比试验数据和理论计算结果，验证了循环函数法定量计算模型的准确性与可靠性。 ③研究了低压省煤器的主要运行特性，这些特性具有普遍性，可以指导生产实践。研究了低压省煤器的最佳安装位置，结果表明，方案的考察和选择应从材料价格、能源供应等角度来综合分析。
[Abstract]:With the development of economy in China, the contradiction between energy and environment is becoming more and more serious. In order to achieve better energy saving and emission reduction, there are many projects in domestic power plants and newly designed thermal power plants that use low-pressure economizer system to recover flue gas waste heat. Due to the difference of calculation methods, the economic evaluation of flue gas waste heat recovery and utilization has been controversial. Under this background, it is urgent to find a reasonable evaluation method for the utilization economy of waste heat of boiler exhaust gas, to improve the energy conversion efficiency of waste heat of exhaust gas and to further reduce the energy consumption of power generation. The recovery and utilization of flue gas waste heat belongs to the system of external heat utilization, which can be quantitatively analyzed by circulation function method. Based on the cyclic function method and from the point of view of counterbalance, a complete mathematical model for local quantitative calculation is established in this paper. These models are applied to the local quantitative analysis of water supply mode, condensate undercooling and so on. Combined with a 300MW subcritical unit and a 1000MW ultra-supercritical unit, the calculation and analysis are carried out respectively. Combined with a 300MW subcritical unit, the quantitative calculation model of cyclic function method is applied to the thermal economic analysis of low pressure economizer. The operation characteristics and optimal installation position of low pressure economizer are studied. The main research results are as follows: 1Inlet coefficient of the final unit is the reflection of the irreversibility of the system. The efficiency of the unit can be improved by reducing the influent coefficient of the final unit and increasing the heat absorption of the cycle. The quantitative calculation model of cyclic function method has the characteristics of clear concept, strong generality and easy to be programmed by computer. (2) the mathematical model of optimal operation of low pressure economizer is established, and the optimal water flow rate is obtained under rated working conditions. When the water flow is 69.2kg/s, the relative increment of unit efficiency is the largest, 0.722. By comparing the experimental data with the theoretical results, the accuracy and reliability of the calculation model of cyclic function method are verified. 3 the main operating characteristics of low pressure economizer are studied, and these characteristics are universal. Can guide production practice. The optimum installation position of low pressure economizer is studied. The results show that the inspection and selection of the scheme should be comprehensively analyzed from the point of view of material price and energy supply.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621

【参考文献】