Thermodynamic Analysis of Supercritical CO2 Part-Flow Cycle and Combined Cycle

被引：0

作者：

Zheng Y. ^{[1
]}

Xu J. ^{[1
]}

Yang X. ^{[1
]}

机构：

[1] The Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization, North China Electric Power University, Changping District, Beijing

来源：

Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | 2018年 / 38卷 / 03期

基金：

中国国家自然科学基金;

关键词：

Combined cycle; Organic Rankin cycle; Supercritical CO[!sub]2[!/sub] cycle; Thermodynamic process; Thermodynamic property; Thermodynamics;

D O I：

10.13334/j.0258-8013.pcsee.161586

中图分类号：

学科分类号：

摘要：

Based on a CO2 turbine with an output power of 1MW under a design condition, calculations were made in different modes of supercritical CO2 cycle in this paper. The result shows that compared to the simple Brayton cycle (SBC), the performance of the regenerative Brayton cycle (RBC) is much better and the thermal efficiency is more than doubled. Furthermore, it is found that the introduction of the part-flow can improve the thermal efficiency of a CO2 cycle in a certain range of part-flow ratio, and the performance of the part-flow Brayton cycle (PFBC) will deteriorate if the part-flow ratio is too small. In order to use the Organic Rankine cycle (ORC) to absorb the waste heat released from the CO2 cycle, the optimized operation modes of the ORC were analyzed. For the superheated degree, the performance of ORCs will deteriorate when the superheated degree increased. This is mainly due to the decreasing of the expansion work. For heat source outlet temperature, there exists an optimum heat source outlet temperature for a fixed heat source inlet temperature, which made the expansion work reach the maximum value. Based on the conclusions above, we combined a CO2 cycle and an ORC as a combined cycle (CBC) to compare its performance with a PFBC under different part-flow ratios. The result shows that thermal efficiencies of CBCs are higher than PFBCs at least 2 percentage points, and when the pinch point is in the preheat section of the coupled heat exchanger (CHE), the performance of the combined cycle is even better. © 2018 Chin. Soc. for Elec. Eng.

引用

页码：814 / 822

页数：8

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