再压缩与部分冷却二氧化碳布雷顿循环热效率对比分析

Comparative Analysis of Thermal Efficiency of Supercritical Recompression Carbon Dioxide Brayton Cycle Systems and Partial Cooling Systems

随着能源技术的迅速发展,超临界二氧化碳发电相关理论和技术的研究得到了越来越广泛的关注。为了探究各参数变化对热效率的影响,基于超临界再压缩二氧化碳布雷顿循环系统和部分冷却系统,进行热效率对比分析。以初压、初温、分流系数、预压压力和预热温度为变量条件,研究再压缩与部分冷却系统的循环效率变化规律,并对两系统各设备的?损以及系统最佳循环效率进行对比。结果表明,初温初压和分流系数对热效率有较大影响。两系统一定存在最优分流系数使得系统达到最佳效率;在一定条件下,初温越高循环效率越高,而初压越高循环效率先增大后减小。循环系统初温720℃,初压20 MPa以下时,部分冷却系统比再压缩系统拥有更高的循环效率,且回热器和冷凝器拥有较低的?损。

With the rapid development of energy technology,there has been growing researches on the theory and technology of supercritical carbon dioxide power generation.Aimed at exploring the effect of variable conditions on thermal efficiency,this paper conducted a thermal efficiency comparative analysis based on supercritical recompression carbon dioxide Brayton Cycle system and partial cooling system.This paper observed the cycle efficiency of recompression and partial cooling systems and compared the energy loss and optimal cycle efficiency of the two systems under variable conditions including initial pressure,initial temperature,shunt coefficient,preload pressure and preheating temperature.The results show that there exists an optimal efficiency in both systems with the optimal shunt coefficient,and that under certain conditions,the cycle efficiency increases first and then decreases as the initial temperature increases.With720℃initial temperature of the circulation system and the initial pressure below 20 MPa,certain cooling systems achieve higher cycle efficiency and cause less energy loss of regenerator and condenser than recompression systems do.