大型燃煤锅炉低温烟气余热综合利用及节能分析

发布时间：2018-01-02 11:29

本文关键词：大型燃煤锅炉低温烟气余热综合利用及节能分析　出处：《华北电力大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着最近几年,燃煤价格的不断攀升以及国内节能减排要求的日益严格,提高燃煤电站全厂热效率、减少机组煤耗、同时降低对周围环境的污染成为我国发展煤电的重点。现阶段,对锅炉低温烟气加以回收利用无疑是一项重要节能措施。本文首先从烟气余热资源合理优化配置的角度,在充分考虑预防烟气低温腐蚀问题的基础上,结合相应热力学分析方法与建模理论,构建了燃煤电站低温烟气余热回收系统所涉及主要换热单元及流程的合理化数学模型,为进一步分析回收烟气低品位能时的优化设计和改造方案奠定了良好的理论基础。在此基础上,论文对上海某典型1000MW燃煤机组开展深入分析,根据其实际运行情况,在烟气余热回收装置的烟气侧连接方式、水侧连接方式、管径、管材的优选等方面提出了几种较为合理可行的方案,并最终确定一套优选改造方案,即利用回热系统中的凝结水来回收排烟余热的方案。最后,论文应用所建模型,对该典型1000MW燃煤机组的改造方案进行了全面的热力学分析,并对低温余热回收方案的节煤收益、节水效果以及该电站加装两级低温省煤器后对尾部烟道带来的影响进行了深入分析。此外,论文也对该机组进行低温烟气余热回收改造的投资成本及变工况运行情况进行了综合分析。本文研究将热力学理论应用于解决燃煤电站锅炉余热利用的工程实际问题,并对典型电站改造方案进行了深入分析,研究结果丰富了余热综合利用领域的分析方法与优化思路,对已投产机组的节能优化改造有一定的参考意义。
[Abstract]:With the rising price of coal and the increasingly strict requirements of energy saving and emission reduction in recent years, the thermal efficiency of the whole plant of coal-fired power station is improved, and the coal consumption of the unit is reduced. At the same time, reducing the pollution of the surrounding environment has become the focus of coal power development in China. The recovery and utilization of boiler low-temperature flue gas is undoubtedly an important energy-saving measure. Firstly, from the point of view of rational allocation of flue gas waste heat resources, this paper takes full account of the prevention of low-temperature corrosion of flue gas. Combined with the corresponding thermodynamic analysis method and modeling theory, the rational mathematical model of the main heat transfer units and processes involved in the waste heat recovery system of low-temperature flue gas from coal-fired power station is constructed. It lays a good theoretical foundation for further analysis of optimal design and retrofit scheme for recovering low-grade energy from flue gas. On this basis, the paper carries out in-depth analysis of a typical 1000MW coal-fired unit in Shanghai. According to its actual operation, several reasonable and feasible schemes are put forward in the aspects of flue gas side connection mode, water side connection mode, pipe diameter, pipe material optimization and so on. And finally determine a set of optimal selection and transformation plan, that is, using condensate in the regenerative system to recover exhaust heat. Finally, the paper applies the established model. A comprehensive thermodynamic analysis of the retrofit scheme of the typical 1000MW coal-fired unit is carried out, and the coal-saving benefits of the low-temperature waste heat recovery scheme are also discussed. The effect of saving water and the influence of installing two stage low temperature economizer on the tail flue of the power station are analyzed. The paper also analyses the investment cost and operation condition of the unit for recovering waste heat from low temperature flue gas. The thermodynamic theory is applied to solve the engineering practice of waste heat utilization of coal-fired power plant boiler in this paper. The problem. The research results enrich the analysis methods and optimization ideas in the field of comprehensive utilization of waste heat, and have a certain reference significance for the energy-saving optimization of units put into operation.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM621.2;TK115

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