电站锅炉低温省煤器设计及前后烟道流场均匀性模拟

发布时间：2018-06-08 05:49

本文选题：低温省煤器 + 锅炉尾部烟道　；参考：《东华大学》2014年硕士论文

【摘要】：随着政府节能改革的深化,电站锅炉尾部烟道的余热利用的重要性日益增长。低温省煤器的引入,极大地提升了锅炉的换热效率,但是随之而来的也有一些问题需要研究者得以重视。因此,合理设置低温省煤器,根据其前后烟道的偏流现象,提出改进方案,改善锅炉尾部烟道低温省煤器前后部分的流场均匀性,可以减少磨损,防止换热设备因磨损而爆管,对于电厂的安全经济运行有极大的意义。本课题基于华东电力设计院的实际工程项目,在全面了解低温省煤器等余热利用设备的基础上,按照设计手册对低温省煤器和空气预热器进行设计计算,得到合理设计参数,再采用此参数,使用计算流体力学的方法,建立起省煤器前后烟道和空气预热器后、除尘器前烟道的数值模型,其中：省煤器前后烟道关注转弯烟道,除尘器前烟道关注分岔烟道,两个数值模型通过对速度场的研究,对不同烟道结构、不同参数流体、不同均流布置下的烟道流场进行数值模拟计算,对比分析得到较优烟道优化方案,改善烟道内流场不均匀性,从而降低了换热设备爆管的可能性,提高热力发电厂机组经济性。通过课题计算得出针对实际工程项目低温省煤器和空气预热器的合理设计参数,按照设计参数的模型分析得出原设计方案存在磨损严重的可能性,通过对省煤器前烟道设置两层导流板：第一层三块导流板,第二层四块导流板,实现转弯烟道和变截面扩展烟道的流场均匀性改善；通过调整除尘器前烟道管道形状、烟道转弯角度和入口流速度,实现长距离烟道的流场均匀性改善,保证进入除尘器的烟气流动分配均匀。通过方案内各因素的调整,能很好实现低温省煤器前后烟道整体流场均匀性的改善,保证锅炉尾部烟道内各余热利用设备的高效运行。同时,本文所做工作也为锅炉尾部烟道流场的优化设计和电厂机组的经济安全运行提供了理论支持和数值参考。
[Abstract]:With the deepening of the government's energy-saving reform, the importance of waste heat utilization in the tail flue of power plant boiler is increasing day by day. The introduction of low temperature economizer has greatly improved the efficiency of boiler heat transfer, but there are also some problems that need to be paid attention to by researchers. Therefore, the reasonable setting of low temperature economizer, according to the deviation phenomenon of the flue before and after, the improvement scheme is put forward to improve the uniformity of flow field in the front and back parts of the low temperature economizer of boiler tail flue, which can reduce the wear and avoid the tube explosion of the heat exchanger because of wear and tear. It is of great significance to the safe and economical operation of power plant. Based on the actual project of East China Electric Power Design Institute, this subject is based on a comprehensive understanding of the low temperature economizer and other waste heat utilization equipment. According to the design manual, the low temperature economizer and the air preheater are designed and calculated, and the reasonable design parameters are obtained. After adopting this parameter and using the method of computational fluid dynamics, the flue and air preheater before and after the economizer are established, The numerical model of flue in front of dust collector, in which: before and after economizer pay attention to turn flue, before dust collector pay attention to bifurcation flue, two numerical models through the study of velocity field, to different flue structure, different parameter fluid, The flow field of flue under different flow sharing arrangement is simulated by numerical simulation, and the optimal flue optimization scheme is obtained by contrast analysis, which can improve the non-uniformity of flow field in flue, thus reducing the possibility of tube burst in heat exchanger. The reasonable design parameters of cryogenic economizer and air preheater for practical engineering project are obtained by calculating the economic efficiency of units in thermal power plant. According to the model analysis of design parameters, the possibility of serious wear in the original design scheme is obtained. The flow field uniformity of the turn flue and the expanded flue with variable cross section is improved by installing two layers of flow guide plate in the front flue of the economizer: the first layer three guide plates and the second layer four flow guide plates; by adjusting the shape of the flue pipe before the dust collector, the flow field uniformity of the flue duct is improved by adjusting the flow field of the flue duct before the dust collector. The flow field uniformity of long distance flue can be improved by turning angle of flue and inlet velocity, and the flow distribution of flue gas entering the dust collector will be uniform. By adjusting all the factors in the scheme, the uniformity of the flow field of the flue before and after the low temperature economizer can be well improved, and the efficient operation of the remaining heat utilization equipment in the flue at the tail of the boiler can be ensured, at the same time, The work in this paper also provides theoretical support and numerical reference for the optimization design of boiler tail flue flow field and the economic and safe operation of power plant units.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621.2

【参考文献】