基于吸收式热泵的热电联产系统节能研究

发布时间：2018-12-30 12:49

【摘要】：火电厂在国家节能减排过程有着重要的意义。随着科学技术日新月异,国内供热机组容量越来越大型化,供热技术模式也呈多样化。传统热电联产的抽凝供热技术模式不能全部回收电厂的冷凝热,利用吸收式热泵的供热技术可以进一步回收电厂的循环水余热,在不扩大热源规模的前提下增加供热量,提高能源利用率。热电联产过程中,抽凝机组耦合吸收式热泵以及传统的抽凝供热模式都需要从汽轮机中低压缸连通管抽汽,吸收式热泵和抽凝供热模式在同样供热环境下需要的抽汽压力品位和抽汽量不同,因此合理确定这两种供热系统的应用条件对大型热电联产机组节能具有重要意义。本文首先采用Ebsilon软件对第一类溴化锂吸收式热泵与600MW火电厂热力系统进行模拟,通过实际数据检验各自热力系统的准确性和适用性。其次在热电联产总热效率式的基础上提出并定义当量抽汽压力概念,作为这两种不同供热模式的热经济评价指标,通过大型热电联产机组耦合吸收式热泵的变工况分析模型,揭示出热网不同回水温度和温升条件下,单效溴化锂吸收式热泵设计条件下COP和驱动热源压力的变化规律；以200MW和300MW直接空冷机组作为案例,对吸收式热泵供热和抽凝供热系统热经济性进行分析,得出：300MW汽轮机因为中低压缸分缸压力在(0.4-1.0)MPa,采用吸收式热泵技术供热优于抽凝供热模式；而200MW额定抽汽压力为0.25MPa,抽凝供热反而优于吸收式热泵技术供热模式。研究表明：可以依据当量抽汽压力为基准判定不同供热模式的经济性,为机组供热改造模式的选取提供参考。
[Abstract]:Thermal power plants are of great significance in the process of national energy saving and emission reduction. With the rapid development of science and technology, the capacity of domestic heating units is becoming larger and larger. The traditional heat and power cogeneration condensate heating technology mode can not completely recover condensate heat from power plant. Using the heat supply technology of absorption heat pump can further recover the waste heat of circulating water in power plant, and increase the heat supply without enlarging the scale of heat source. Improve energy efficiency. In the cogeneration of heat and electricity, the coupling absorption heat pump of the condensing unit and the traditional condensing heating mode all need to extract steam from the connected tube of the middle and low pressure cylinder of the steam turbine. Absorption heat pump and condensate heating mode need different extraction pressure grade and extraction steam quantity in the same heating environment, so it is important to reasonably determine the application conditions of these two heating systems for the energy saving of large cogeneration units. In this paper, the first type of libr absorption heat pump and 600MW thermal power plant thermodynamic system are simulated by Ebsilon software. The accuracy and applicability of their respective thermal systems are verified by actual data. Secondly, on the basis of the total heat efficiency of cogeneration, the concept of equivalent extraction pressure is proposed and defined. As the thermal economic evaluation index of these two different heating modes, the off-condition analysis model of coupled absorption heat pump for large cogeneration units is presented. The variation of COP and driving heat source pressure under the conditions of different backwater temperature and temperature rise in heat network and single effect libr absorption heat pump are revealed. Taking 200MW and 300MW direct air cooling units as examples, the heat economy of absorption heat pump heating and condensing heating system is analyzed. It is concluded that the 300MW steam turbine has a cylinder separation pressure of (0.4-1.0) MPa, because of the middle and low pressure cylinder. The absorption heat pump technology is better than the condensate heating mode. However, the rated extraction pressure of 200MW is 0.25 MPA, which is better than the absorption heat pump technology. The results show that the economy of different heating modes can be judged based on the equivalent extraction pressure, which provides a reference for the selection of the heating transformation mode of the unit.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM621

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