吸收式热泵回收汽机乏汽余热技术研究

发布时间：2018-10-24 22:56

【摘要】：抽汽供热和低真空供热是目前热电联产集中供热的主要方式,而基于吸收式热泵的循环水提质新技术具有进一步提高机组热效率和供热能力的潜力。工程实践表明,降低冷源损失是提高汽轮机组效率最有效的方法。本文以中电投蒙东能源通辽发电总厂200MW抽汽机组为例,提出了基于吸收式热泵的汽轮机乏汽热电联供工艺。首先应用Matlab对溴化锂吸收式热泵的循环过程进行模拟,分析了驱动热源温度等参数对热力过程的影响规律,并以机组设计参数为基础,针对额定工况和最大工况,确定了供热负荷不变和发电功率不变两种方案,对抽汽供热与循环水吸收式热泵采暖期供热的联产机组性能指标进行了对比分析。计算表明：热泵机组供热系数达1.65时,在发电量不变方案的额定工况条件下,循环水吸收式热泵供热机组热效率达到了77.7%,供热负荷达到83.47MW,分别比抽汽供热提高了22.43个百分点和31.3MW,供热能力提高了60%。最后,针对非供热期乏汽余热没有回收的问题,提出了一种乏汽余热综合利用系统,以热定电,提高汽轮机乏汽资源利用率。可以采用溴化锂吸收式热泵机组提取凝汽器循环冷却水的余热加热低加凝结水来实现。根据机组实际情况及经济性选用“一号低加抽汽作为驱动热源加热一号低加凝结水”方案和“三号低加抽汽作为驱动热源加热二级低加凝结水”方案。前者可降低发电煤耗0.21g/kWh,后者可降低发电煤耗0.25g/kWh,一共可以降低发电煤耗0.46 g/kWh。研究表明,循环水吸收式热泵将低品位循环水余热加以提质利用,降低了机组冷源损失,提高了机组热效率和供热负荷,而提出的汽轮机乏汽余热综合利用工艺,将实现汽轮机组收益最大化。研究结果可为抽汽机组的节能改造提供思路及方案。
[Abstract]:Extraction heating and low vacuum heating are the main ways of heat and power cogeneration centralized heating, and the new technology of circulating water quality improvement based on absorption heat pump has the potential to further improve the heat efficiency and heating capacity of the unit. The engineering practice shows that reducing the loss of cold source is the most effective method to improve the efficiency of steam turbine unit. In this paper, taking the 200MW pumping unit of CNEC Mendong Energy Tongliao General Power Plant as an example, a combined steam turbine heat and power supply process based on absorption heat pump is proposed. Firstly, the circulating process of libr absorption heat pump is simulated by Matlab, and the influence of driving heat source temperature and other parameters on thermal process is analyzed. Based on the design parameters of the unit, the rated and maximum operating conditions are analyzed. The two schemes of constant heating load and power invariant are determined. The performance indexes of cogeneration units in heating period of extraction steam heating and circulating water absorption heat pump are compared and analyzed. The calculation shows that when the heat supply coefficient of the heat pump unit reaches 1.65, under the condition of rated working condition of the constant power generation scheme, The heat efficiency of circulating water absorption heat pump is 77.7%, the heating load is 83.47 MW, which is 22.43% and 31.3MW higher than that of extraction heating, respectively, and the heating capacity is increased by 60%. Finally, aiming at the problem that the waste heat of the steam is not recovered in the non-heat supply period, a comprehensive utilization system of the waste heat of the spent steam is put forward to improve the utilization ratio of the spent steam resource of the steam turbine. Lithium bromide absorption heat pump unit can be used to extract the condenser circulating cooling water by low heating and condensate. According to the actual situation and economy of the unit, the scheme of "No. 1 low adding steam extraction as driving heat source to heat 1 low additive condensate water" and "No. 3 low add steam extraction steam as driving heat source to heat secondary low adding condensate water" is selected. The former can reduce coal consumption by 0.21g / kWhand the latter by 0.25g / kWh. the total coal consumption can be reduced by 0.46g / kWh. The research results show that the waste heat of low grade circulating water can be extracted and utilized by circulating water absorption heat pump, which can reduce the loss of unit cold source, improve the heat efficiency and heat supply load of unit, and put forward the comprehensive utilization technology of waste heat of steam turbine. The profit of steam turbine unit will be maximized. The results can provide ideas and schemes for energy-saving retrofit of steam extraction units.
【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

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