热力循环流程重构能效分析新方法:循环拆分法  

A New Analytical Method for Process Modification of Thermal Cycle:Cycle Splitting Method

作　　者：杨勇平 辛团团 许诚 YANG Yongping;XIN Tuantuan;XU Cheng(Key Laboratory of Power Station Energy Transfer Conversion and System of Ministry of Education(North China Electric Power University),Changping District,Beijing 102206,China)

机构地区：[1]电站能量传递转化与系统教育部重点实验室(华北电力大学),北京市昌平区102206

出　　处：《中国电机工程学报》2021年第20期7003-7013,共11页Proceedings of the CSEE

基　　金：国家自然科学基金创新研究群体科学基金(51821004)。

摘　　要：流程重构是提高热力循环效率的有效途径,然而重构后的循环流程配置往往较为复杂。为简单直观地揭示热力循环不同流程配置的节能机制,提出一种具有普适性的热力循环能效分析新方法——"循环拆分法"。该方法基于热力学第一定律,将复杂热力循环拆分为基础循环与若干等效"小循环";拆分获得的小循环可直接用于分析热力循环流程重构的节能机制,指导系统流程优化。以蒸汽朗肯循环与超临界二氧化碳布雷顿循环为例,对典型循环的拆分过程进行了图示化描述和公式化表达,并分析了多种流程重构手段的节能效益;基于循环拆分法,对现有超临界二氧化碳布雷顿循环开展流程优化,进一步提高了循环效率。Process modification and optimization is an important way to improve the efficiency of the thermal cycles.However,the forms and processes of the modified cycles are usually complex.To reveal the energy saving mechanism of the cycle process modification in a simple and clear way,a new general analytical method was proposed — "cycle splitting method".Based on the first law of thermodynamics,this method split the complex thermodynamic cycle into a basic cycle and several equivalent "simple cycles";then,the split simple cycle could be used to reveal the energy saving mechanism of the process modification for thermodynamic cycles,which helped to guide the process optimization.Taking steam Rankine cycle and supercritical carbon dioxide(S-CO2)Brayton cycle as case study,the cycle splitting processes of the typical complex cycles were visually illustrated and modeled by energy balance equations to analyze the energy saving effectiveness of several process modification measures.Based on the proposed cycle splitting method,the process of the conventional combined S-CO2 cycle was further optimized to improve the cycle efficiency.

关 键 词：热力学分析 循环拆分法 节能机理 蒸汽朗肯循环 超临界二氧化碳布雷顿循环 化学回热 

分 类 号：TK123[动力工程及工程热物理—工程热物理]