【作者】 陈立军；

【导师】 杨善让；

【作者基本信息】 华北电力大学（河北） ， 热能工程， 2010， 博士

【摘要】 煤炭在我国一次能源结构中的主导地位,决定了在电力生产中以煤电为主的格局在未来的几十年内不会根本改变。在富煤缺水的北方地区建设空冷电站,“西电东送”是我国开发大西部的一个重大举措。直冷技术得到广泛应用,但存在煤耗高及环境适应能力差等问题。因此,研究一种新的系统,既具有直冷系统高的节水率,又有湿冷机组相近的背压,是电站空冷界追求的目标,对空冷技术的发展具有重要理论意义和巨大的实用价值。提出了一种电站汽轮机凝汽器新型间接空冷系统(以下简称复合空冷系统),它通过特制的双相变换热器将制冷循环及与其并联的逆制冷循环和蒸汽动力循环串接耦合,以使系统能根据环境温度的高低,分别利用正、逆制冷循环的相互切换和制冷设备运行参数的调整将蒸汽动力循环的平均放热温度降到和水冷系统相近或更低,提高机组的效率及环境适应能力。在环境高温时段,制冷循环运行使排汽维持在某一合理水平,保证汽轮机安全、经济稳定地运行。讨论了汽轮机排汽潜热的利用原理,提出了排汽潜热的外利用和内利用的概念,并基于热力学分析给出了排汽潜热的可利用指标。在严寒地区,环境低温时段,可以进行逆制冷循环的动力利用,带动原动机输出动力或带动发电机发电。从能级匹配的观点来看,吸收制冷循环相对更为合理,体现了能量的“梯级利用、按质用能”原则。首次提出了基于氨吸收式制冷复合空冷系统(以下简称新型系统),新型系统利用氨吸收制冷循环的设备代替了原系统能耗巨大的压缩机。预测了复合空冷系统的主要效果,并进行了相应的经济、社会效益估算;为定量分析复合空冷系统的经济性同时也便于设计选型,建立了性能评价指标;建立了复合循环空冷和传统直冷的热力学模型,详细分析了复合空冷的热力学性能,分析了复合空冷机组收益产生的原因。以霍林河电厂在建亚临界600MW机组及气温环境条件为例,分别对直冷和复合空冷进行了经济技术分析,结果表明复合空冷系统投资大于直冷系统,但投资可在运行不到一年内收回。本文的最后,指出了有待进一步深入研究的问题。得出结论:复合循环空冷系统的原理可信,技术可行,效果显著。更多还原

【Abstract】 In the coming several decades, coal-based model of the electricity production will not change while the coal still plays a dominant role of primary energy sources in our country. Building power plants in northwest of China where coal-rich and arid region, which is a key step of develop-the-west strategy,called“Electric Power Transmission from West to East”.The direct-cooling technology is used widely, but there is any problem including high coal consumption and poor environmental adaptation. Therefore, a new system is expected, which has not only high water saving of direct cooling system, but also low back-pressure close to wet unit. It has important theoretical significance and great practical value for the development of air-cooling technology.A new indirect air cooling system for steam condenser in power plant was presented in this paper, in which the steam power cycle was coupled with the positive and negative sequence refrigerating cycle(hereinafter called“combined cycle air cooling system”or CCACS)by means of a special dual-phase change heat exchanger. According to the ambient temperature, the combined power and refrigeration cycle was expected to work in positive or negative order for keeping the turbine back pressure to water cooled level or more lower. At the same time, it can increase unit efficiency and environmental adaptability.From the view point of energy utilization, absorption refrigeration cycle is relatively more reasonable. It is consistent with the principle of using energy that" cascade utilization, use according to the quality". A new indirect air cooling system based on ammonia absorption refrigeration cycle (Next shall be abbreviated to new system) in power plant was presented. In high temperature, it replaces compressor with ammonia absorb refrigeration equipment to reduce energy consumption.This thesis not only predicted the effects, but evaluated the potential economic and social benefits. To quantitate analysis and facilitate type selection, some criteria were established on which the performance evaluation of CCACS is based. The thermodynamics models of direct air cooling system and CCACS was made, and the performance of CCACS was analyzed in detail. Then the income causation of the CCACS was obtained. For an example, one 600MW unit based on the temperature environmental conditions in Huo lin he power plant, Economic and Technical Analysis both direct cooling system and CCACS was done, and the results showed that the investment could be recovered within less than a year, indicating the feasibility of the CCACS.Finally this thesis points out the unsolved questions for the new style air cooling system and makes conclusions that the principle is trustworthy, the technology is feasible and effects are outstanding for the new cooling system.更多还原