燃气—蒸汽联合循环底循环系统参数匹配及分析

发布时间：2018-03-04 23:24

本文选题：底循环系统　切入点：集成匹配　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：在当今世界寻求能量的高效利用、环境的友好相处大格局下,燃气-蒸汽联合循环以其高效率、低排放的优良特性受到越来越多的关注和发展。联合循环由燃气轮机顶循环和余热锅炉与蒸汽轮机共同构成的底循环组成,针对已定燃气轮机的联合循环,底循环系统的集成匹配及其变工况研究具有重要意义。本文研究内容是“基于某重型燃机的燃气-蒸汽联合循环系统设计平台开发”项目的重要组成部分。根据某型燃机的设计工况排气参数,建立了单压、双压无再热、双压再热、三压无再热、三压再热五种底循环系统流程模型。基于热力学第一定律,以底循环功率Pst最高为目标函数,对五种流程蒸汽参数进行了详细的匹配研究,得出了蒸汽压力的匹配规律。在最优匹配结果的基础上,增加约束条件,得到系统综合分析下的设计参数。并比较讨论了五种流程综合分析下的循环性能特性。最后,以三压无再热底循环参数匹配结果作为设计条件,建立底循环系统流程的变工况计算模型,开展了底循环流程各节点参数的变工况趋势分析。结果发现,随着燃机功率的下降,高压、低压省煤器接近点温差降低,出现了零和负值,造成了省煤器出口水的汽化。针对低负荷时省煤器出现的汽化现象提出了两种解决方案,即重新设计底循环节点温差和接近点温差,以及改进底循环流程结构,分析了两种方案对于联合循环底循环性能的影响。本文针对燃气-蒸汽联合循环系统设计工况和变工况的研究成果为底循环系统设计和参数匹配提供了有意义的指导。
[Abstract]:In today's world, the gas-steam combined cycle is highly efficient in seeking the efficient use of energy and the friendly coexistence of the environment. The excellent characteristics of low emission have attracted more and more attention and development. The combined cycle is composed of the top cycle of gas turbine and the bottom cycle of waste heat boiler and steam turbine, aiming at the combined cycle of fixed gas turbine. It is of great significance to study the integrated matching of bottom cycle system and its variable working conditions. The research content of this paper is an important part of the project of "Development of Gas-steam combined cycle system Design platform based on a heavy Gas engine". Exhaust parameters of a certain type of gas turbine under design conditions, The flow models of single pressure, double pressure without reheat, double pressure reheat, three pressure reheat and three pressure reheat are established. Based on the first law of thermodynamics, the maximum bottom cycle power Pst is taken as the objective function. The matching law of steam pressure is obtained through the detailed matching of five kinds of steam parameters. On the basis of the optimal matching result, the constraint condition is added. The design parameters under the system comprehensive analysis are obtained, and the cycle performance characteristics of the five processes are compared and discussed. Finally, the matching results of three pressure and no reheat bottom cycle parameters are taken as the design conditions. The off-condition calculation model of bottom circulation system flow is established, and the variable working condition trend analysis of each node parameter of bottom circulation system is carried out. The results show that with the decrease of power of gas turbine, the temperature difference of approaching point of low pressure economizer decreases with the decrease of power of gas turbine. The zero and negative values have resulted in the vaporization of the outlet water of the economizer. Two solutions to the vaporization phenomenon of the economizer under low load are put forward, that is, redesigning the temperature difference of the bottom cycle node and the temperature difference of the close point. And to improve the bottom cycle flow structure, The effects of two schemes on the performance of the combined cycle bottom cycle are analyzed. The research results of the gas-steam combined cycle system design conditions and variable conditions provide a meaningful guidance for the bottom cycle system design and parameter matching.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM611.31

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