低温余热蒸汽闪蒸-双工质联合循环发电系统热力分析  

Thermodynamic Analysis of a Low Temperature Waste Heat Steam Flash Vaporization-Dual Working Medium Combined Cycle Power Generation System

作　　者：杨新乐[1] 黄菲菲[1] 赵阳升[2] 戴文智[1] 

机构地区：[1]辽宁工程技术大学机械工程学院,辽宁阜新123000 [2]太原理工大学采矿工艺研究所,山西太原030024

出　　处：《热能动力工程》2014年第1期29-34,105-106,共6页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金重点项目(50534030);国家自然科学青年基金项目(51104083)

摘　　要：为充分回收矿藏热采过程尾端低温蒸汽余热,提出一种适于蒸汽回收的新型闪蒸-双工质联合循环发电系统,以热力学第一、第二定律为基础,建立了该联合循环热力模型,采用R245fa为循环工质,编制计算程序对系统热效率、输出功率及火用效率进行了热力分析,并将其与单纯闪蒸、双工质朗肯循环进行性能对比。结果表明,在热源温度110℃、压力0.14 MPa情况下,净输出功随闪蒸压力、双工质循环蒸发压力的增大均呈先增大后减小的趋势,当闪蒸压力在0.048 33 MPa,低压级双工质循环蒸发压力为0.389 6 MPa时,系统整体及闪蒸-双工质阶段均存在最大功率,分别为6 249.2 kW、429.2 kW;热效率则随闪蒸压力增大先增大后减小,而随双工质压力的增大不断增大。其中双工质循环的热效率均低于联合循环,在多数情况下单纯闪蒸循环的热效率基本等于联合循环的热效率;火用效率变化规律与净输出功变化规律相同。To fully recover the low temperature steam waste heat in the tail portion of hot production processes of various mine deposits,proposed was a new type flash vaporization-dual working medium combined cycle power generation system.On the basis of the first and second law of the thermodynamics,a model for such a system was established with R245fa serving as the working medium of the cycle and a program was prepared and designed to perform a thermodynamic analysis of the thermal efficiency,output power and exergy efficiency of the system and a comparison of the performance between a simple flash vaporization and dual working medium Rankine cycle. It has been found that under the condition of the heat source attaining a temperature of 110 ℃ and a pressure of 0. 14 MPa,the net output power of the system will assume a tendency of first increase and then decrease with an increase of the flash vaporization pressure and the vaporization pressure of the dual working medium cycle. When the flash vaporization pressure stands at 0. 04833 MPa and the vaporization pressure of the low pressure stage dual working medium cycle vaporiza-tion pressure hits 0. 3896 MPa,the system as a whole and the flash vaporization-dual working medium section will all have their maximum output power,being 6249. 2 and 429. 2 kW respectively. The thermal efficiency will first increase and then decrease with an increase of the flash vaporization pressure but continuously grow with a rise of the pressure of the dual working medium. Among them,the thermal efficiency of the dual working medium cycle is invariably lower than that of the combined cycle. In the most cases,that of the single flash vaporization cycle is basically equal to that of the combined cycle while the law governing the variation of the exergy efficiency is identical to that governing the variation of the net output power.

关 键 词：低温余热蒸汽 联合循环 闪蒸循环 双工质循环 热力分析 

分 类 号：TK212[动力工程及工程热物理—动力机械及工程]