【作者】 李岩；

【导师】 付林；

【作者基本信息】 清华大学 ， 土木工程， 2012， 博士

【摘要】 发掘热电联产的节能潜力，提高热电联产集中供热的可实施性，已成为我国节能工作的一项重点任务。针对目前热电联产供热能力不足、集中热网输送能力不足的瓶颈问题，清华大学提出了“基于吸收式换热的热电联产集中供热系统（简称Co-ah系统）”，可以同时实现电厂的凝汽余热利用和热网的大温差输送热量。本文围绕Co-ah系统集成配置和运行调节方面的问题展开研究，成果用于指导系统的优化设计和运行。首先，针对凝汽余热利用引发的大型供热机组安全及能效的机理问题，提出机组最大抽凝比的定义，确定了在安全性约束条件下，基于凝汽余热利用的大型供热机组抽、凝参数的关联与选择依据，并指出应从低压缸凝汽流有效焓降和凝汽流量两方面因素综合考虑凝汽余热利用对机组发电的影响。针对系统能效的评价，指出Co-ah系统通过凝汽余热利用可以实现3种基本目标；针对系统供热和机组发电两方面因素的影响，提出供热等效电的定义及其分析方法，用来分析抽汽和凝汽两种热源的“质”与“量”对系统全工况运行能效的影响，由此完善了Co-ah系统综合能效评价方法。针对系统的集成配置，归纳了湿冷系统和空冷系统机组冷端连接的形式和吸收式热泵机组的型式。引进系统抽凝比的定义，通过对系统抽凝比与机组抽凝比匹配关系的分析，明确了Co-ah系统性能优化的方向。在此基础上，提出了供热机组参数和一次网系统参数的优化原则及方法。明确了吸收式换热机组与电厂吸收式热泵机组配置的匹配关系，以及通过增设吸收式换热机组改善系统性能的合理性。针对系统的运行，提出了适合Co-ah系统的热网综合运行调节方式；优化供热机组的运行方式，提出并论证了变背压及变抽凝比的调节思路，根据能源梯级利用的原理，提出热网水系统串联布置和冷端联通布置的系统形式，在运行中提高系统能效，并缓解冷却塔冬季防冻的安全性问题。将理论研究与工程实践结合，在大同市建成首个大规模工业应用性示范项目，通过实测检验了两类吸收式设备的性能和系统运行的效果。通过对电厂首站系统的试验与分析，确定了系统在实际运行中合理的运行工况和运行方式，由此验证了部分理论研究工作的成果。更多还原

【Abstract】 One of the emphasis tasks of energy saving is to explore the energy savingpotential of co-generation and enhance the feasibility of co-generation district heating inChina. In view of the insufficient ability of co-generation heating source and poordelivery capacity of heating network, Tsinghua University proposes a new type ofdistrict heating system with cogeneration based on absorption heat exchange (Co-ahSystem). It could recycle exhaust steam waste heat of power plant and transport heatwith a larger temperature difference. This paper focuses on the configuration and theoperation strategy of Co-ah system. These research results may be of guidance fordesign and operation of Co-ah system.Because the safety and efficiency of large heating unit is affected by exhaustedheat recovery from condensers, the maximum ratio of extraction steam and condensedsteam of turbine is defined. In a safe condition, define the parameter of large extractioncondensing combination unit based on exhaust steam waste heat utilization. As evaluatethe effect of exhausted heat recovery from condensers on generate electricity, botheffective enthalpy drop and condensed steam flow of low pressure cylinder should beconsidered.For evaluate the energy efficiency, this paper puts forward three roles of exhauststeam waste heat utilization of Co-ah system. Considering the influence of exhauststeam waste heat utilization on heating and power, the definition of heating equivalentelectric is given. It is used to analyze that how quality and quantity of extraction steamand condensed steam effect the operation efficiency on the total operating period. Thusa comprehensive efficiency evaluation method of Co-ah system is completed.For the system configuration of Co-ah system, the terminal connecting formats ofair and wet cooling steam turbine and the type of absorption heat pump are sum up. Thedefinition of the ratio of extraction steam and condensed steam of Co-ah system isproposed. By analysis the matching relations of the ratio of system and turbine units, theCo-ah system performance optimization direction is clear. Some suggestions are given,namely, parameter optimization principle and method of the cogeneration unit andnetwork system; the matching relations of absorption heat exchanger unit and absorption heat pump; the rationality of improving the performance of the systemthrough adding absorption heat exchange units.For the operation control of Co-ah system, a suitable operation adjustment mode ofheating network and changing back pressure operation ideas of turbine are proposed.Based on the method of cascade utilization of energy, this paper puts forward twooptimization method: heat network water series arrangement and linking with coldterminal, to improve energy efficiency further in the operation and ease thecontradiction of exhaust steam waste heat utilization and condenser winter antifreeze inplant.To integrate theory research with project practice, the first large-scale industrialapplication demonstration project is built in Datong city. By actual test, the performanceof two kinds of absorption units is verified. In addition, based on the measurement andanalysis of head power system, reasonable operation condition and mode is determined,and the theoretical research of this paper is verified.更多还原