大型电站锅炉高温受热面热偏差分析研究

发布时间：2018-04-16 18:52

本文选题：电站锅炉 + 高温受热面　；参考：《华北电力大学》2014年硕士论文

【摘要】：随着社会经济的飞速发展,电力需求日益增大,为满足电力供应,火力发电机组也越来越向着大容量、高参数、低污染环保型方向发展。然而,大型电站锅炉高温受热面的超温爆管事故时有发生。过热器是锅炉承压部件中工作温度最高的受热面,管内流过的是高温高压蒸汽,其传热性能较差,而管外又是高温烟气,所处环境恶劣,发生事故的比例非常大。大型电站锅炉蒸汽参数高,一旦发生超温爆管事故,不仅会损失大量的工质和燃料,降低机组的经济性,而且还会影响到机组的安全性,甚至会冲击电网的稳定性。鉴于上述原因,关于大型电站锅炉高温受热面热偏差的成因及热偏差、壁温计算方法的研究就具有非常重要的实际意义。针对此问题,本文首先对锅炉高温受热面热偏差理论进行了详细的介绍与分析,从蒸汽侧流量偏差、烟气侧吸热偏差以及同屏热偏差三个方面展开讨论。然后以某大型电站600MW超临界锅炉为研究对象,通过FLUENT数值模拟软件,选取最大负荷工况,对整个炉膛进行了燃烧数值模拟计算对炉膛燃烧进行了数值模拟,求解得出了炉内烟气温度和速度的分布,并在此基础上,进行了屏式过热器的壁温计算。在总结原有壁温计算方法的基础上,探讨了改进的壁温计算方法,并针对该锅炉建立了合适的壁温计算模型,将屏式过热器管子划分为若干小单元,逐个计算每个单元管段的换热量,并最终求得每个管段的壁温,对比计算结果,得出管壁温度的分布情况,找出管壁温度最高的危险点并分析原因。对于该锅炉进行低氮燃烧改造方案的选择具有重要的参考价值,并对过热器系统受热面的优化设计,事故分析具有一定的指导意义。
[Abstract]:With the rapid development of social economy, the demand for electricity is increasing day by day. In order to meet the demand of power supply, thermal power generating sets are developing towards the direction of large capacity, high parameter and low pollution.However, the overtemperature tube burst accident of the high temperature heating surface of large power station boiler occurs from time to time.Superheater is the heating surface with the highest working temperature in the pressure-bearing parts of the boiler. The high temperature and high pressure steam flows through the tube, its heat transfer performance is poor, and the high temperature flue gas is outside the tube, so the environment is bad and the proportion of accidents is very large.Because of the high steam parameters of large power plant boiler, once the overtemperature tube burst accident occurs, it will not only lose a large amount of working fluid and fuel, reduce the unit's economy, but also affect the safety of the unit and even impact the stability of the power grid.In view of the above reasons, the study of the calculation method of wall temperature is of great practical significance for the cause of the heat deviation of the high temperature heating surface and the thermal deviation of the high temperature heating surface of the large power station boiler.In order to solve this problem, this paper first introduces and analyzes the theory of heat deviation of boiler's high temperature heating surface in detail, and discusses it from three aspects: steam side flow deviation, flue gas side endothermic deviation and same screen heat deviation.Then taking the 600MW supercritical boiler of a large power station as the research object, the combustion numerical simulation calculation of the whole furnace is carried out through the FLUENT numerical simulation software and the maximum load condition is selected, and the combustion of the furnace is numerically simulated.The distribution of flue gas temperature and velocity in the furnace is obtained, and the wall temperature of the screen superheater is calculated.On the basis of summing up the original wall temperature calculation method, the improved wall temperature calculation method is discussed, and an appropriate wall temperature calculation model is established for the boiler. The tube of the screen superheater is divided into several small units.The heat transfer of each unit pipe section is calculated one by one, and the wall temperature of each section is finally obtained. The distribution of pipe wall temperature is obtained, and the highest dangerous point of pipe wall temperature is found out and the reason is analyzed.It has important reference value for the selection of low nitrogen combustion retrofit scheme for the boiler, and has certain guiding significance for the optimization design of heating surface of superheater system and accident analysis.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621.2

【参考文献】