超临界二氧化碳部分冷却布雷顿循环参数优化

Parameters Optimization of a Supercritical CO_2 Partial Pre-cooling Brayton Cycle

针对一级再热超临界二氧化碳部分冷却布雷顿循环建立循环热力学模型,分析循环关键参数对循环热效率的影响。结果表明:最佳再热压力的最佳值约为第一级透平的0.5倍;在给定条件下,使压缩机入口参数接近于临界值、减小夹点温差、提高透平入口温度、提高压缩机效率和透平效率都可以提高循环热效率;透平效率对循环热效率的影响大于压缩机效率对循环热效率的影响。

A thermodynamic model was established for the single-reheat supercritical COz （S-CO2） partial pre-cooling Brayton cycle, so as to study the effects of key cycle parameters on the thermal efficiency of the cycle. Results show that the reheat pressure exists an optimal value, which is about 0.5 times of the first turbine inlet pressure. Under given conditions, the cycle thermal efficiency could be increased by making the inlet parameters of the compressor be close to its critical value, decreasing the pinch point temperature difference, increasing the turbine＇s inlet temperature, or increasing the efficiency of the turbine and the compressor, etc. Moreover, it can be found that the influence of the turbine efficiency on the cycle thermal efficiency is greater than that of the compressor efficiency.