【作者】 张甜甜；

【导师】 李晓冬；

【作者基本信息】 哈尔滨工业大学 ， 供热供燃气通风及空调工程， 2011， 硕士

【摘要】 热电联产在冬季能够明显提高能源利用效率,减小环境负荷;但是到了夏季,冬季的供暖热负荷不复存在,热电厂开始以纯火力发电厂的形式运行,大大浪费低品位的能量,对环境的负面影响很大;另外,在热电企业中,夏季产汽量过剩的现象大量存在,如何利用富余蒸汽并寻求合理的热电厂夏季运行方式显得尤为重要。本文首先根据丰原电厂实际运行情况和潜在供冷需求,提出了适合于该电厂的利用富余蒸汽进行集中供冷的方案,包括吸收式制冷改造系统、汽轮机带压缩式制冷系统以及联合循环系统,定性分析了这些系统的可行性。基于压缩式和吸收式制冷的原理,选取了合适的系统计算模型,在此基础上对吸收式系统、汽轮机带压缩式系统及中间压力分别为0.8MPa、0.6MPa、0.4MPa的联合循环系统进行了详细的热力计算,确定了设计工况下各系统各种设备的热负荷以及换热面积,对比了各系统设计工况下的过热蒸汽耗量。在完成各系统的热力计算的基础上,分析了冷媒水温度、冷却水温度以及热源参数对吸收式系统的影响,分析了冷媒水温度、冷却水温度、汽轮机的机械功传递效率以及热源参数对汽轮机带压缩式系统和联合循环系统的影响。对冷媒水温度、冷却水温度和传递效率对各种系统的影响程度,分析了在传递效率不同的情况下哪种系统的省汽优势最大。在进行基本设备选型的基础上确定了各系统的初投资和年运行费用,基于一次能耗能效比的方法比较了各系统的热经济性,并基于费用年值、净现值以及动态回收期等经济性分析方法对各种系统的经济性进行了比较分析,得出了各系统在热经济性和经济性方面的优劣。目前热电厂的集中供冷项目基本都是由电厂的蒸汽驱动吸收式制冷机制冷,型式比较单一,这在一定程度上限制了热电厂集中供冷的发展。本课题旨在提出几种新型的蒸汽驱动的集中供冷系统,并将几种系统与吸收式系统进行对比为在热电厂中进行集中供冷改造提供新的思路和方法,对在热电厂利用富余蒸汽进行集中供冷有一定的积极作用。更多还原

【Abstract】 The cogeneration system improves the rate of energy utilization and reduces the adverse impact on the environment; but in winter, for heat load no longer exists, cogeneration plant starts to operate in a coal-fired power plant way. This shift may cause some bad effects, such as wasting low-grade energy and increasing the adverse impact on the environment. Additionally, there is so much surplus steam in cogeneration plants in summer. It proves to be important to find out the reasonable way to use the surplus steam and the proper method which cogeneration plants operate in summer.This paper puts forward some district cooling systems such as Li-Br absorption refrigeration system, steam-driving compression refrigeration system and combined cycle system, which can be used to consume surplus steam in Fengyuan cogeneration plant. This paper also analyzes the feasibilities of each system qualitatively.On the basis of the principles of compression refrigeration and absorption refrigeration, this article selects the proper calculation models for every system and carries on the thermal calculation of the absorption system, steam-driven compression system and combined-cycle system with the mid-pressure of 0.8MPa, 0.6MPa, 0.4MPa. Further, the heat loads and heat transfer areas are calculated and the amount of surplus steam consumption is compared and analyzed.Since the thermal calculation of every system is carried on, the impacts on absorption system caused by chilled water temperature, cooling water temperature and parameters of surplus steam are analyzed; the impacts on steam-driven compression system and combined-cycle system caused by chilled water temperature, cooling water temperature, parameters of surplus steam and transfer efficiency of the turbine are analyzed. The levels of effect to each system as well as the amount of surplus steam consumption in each system are compared.On the basis of selecting the equipments of all the systems, the initial investments and annual operating costs are calculated. The thermal economy indexes are evaluated by means of comparing the energy efficiency ratio of each system, and the economic indexes are evaluated by means of comparing the annual costs, net present values (NPV) and dynamic recovery periods. The system’s advantages and disadvantages of thermal economy and economy are concluded.Nowadays, district cooling in cogeneration plant are always achieved by means of absorption refrigeration driven by surplus steam in power plants. The development of district cooling in power plants is limited by the lack of flexibility. This paper is to propose several new centralized steam-driven cooling systems and compare these systems with traditional absorption system. This article contributes to the development of CCHP by providing some new ideas and methods for district cooling in power plants.更多还原