Impact of Startup Strategy and Buffer Tank Volume on the Compressor Inlet State for a 3-MW sCO2 Brayton Cycle

  • ZHAO Decai ,
  • WANG Bo
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  • 1. Key Laboratory of Advanced Energy and Power, Institute of Engineering Thermophysics (IET), Chinese Academy of Sciences (CAS), Beijing 100190, China
    2. University of Chinese Academy of Sciences, Beijing 100049, China

Online published: 2025-01-09

Supported by

This work is supported by the National Science and Technology Major Project of China (Grant No. 2017-I-0002-0002) and Major National Science And Technology Infrastructure “High-Efficiency and Low-Carbon Gas Turbine Research Facility” (Grant No. 2017-000052-73-01-001569).

Copyright

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2024

Abstract

The supercritical carbon dioxide (sCO2) Brayton cycle system has become an emerging and highly promising method of thermal power conversion due to its efficiency advantage, system compactness, and excellent adaptability of the heat sources. For the low carbon sCO2 Brayton cycle testbed with cycle output power approaching 3 MW, a relatively detailed dynamic simulation model of the entire system is constructed to explore the dynamic response characteristics of the system with different startup strategies and different buffer tank volumes during the startup process. The simulation results indicate that the smaller the volume of the buffer tank, the more rapid and obvious the parameter fluctuation in the buffer tank during the startup. Assuming the allowable relative deviation limit of density is 5%, then the ratio of the buffer tank volume to the volume of the entire closed loop should not be lower than 36.80%. The strategy of simultaneous temperature and speed increase during turbine bypass start can effectively reduce the fluctuation of compressor inlet parameters and reach the steady-state more quickly. This paper provides the recommended matching table for the opening of the turbine bypass valve (TBV) and the main regulating valve (MGV) to reduce the parameter fluctuation during the bypass switching. The effectiveness of the proposed turbine bypass and bypass switching startup strategy is verified by simulation, which may be used as a reference for test bench’s future debugging and operation.

Cite this article

ZHAO Decai , WANG Bo . Impact of Startup Strategy and Buffer Tank Volume on the Compressor Inlet State for a 3-MW sCO2 Brayton Cycle[J]. Journal of Thermal Science, 2025 , 34(1) : 159 -175 . DOI: 10.1007/s11630-024-1994-0

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