Thermodynamic analysis and optimization of the combined supercritical carbon dioxide Brayton cycle and organic Rankine cycle‐based nuclear hydrogen production system

Abstract

The Supercritical Carbon Dioxide Brayton Cycle (SCBC) with high efficiency is a very promising thermodynamic cycle to replace the Steam Rankine Cycle (SRC) as the power cycle of a Nuclear Hydrogen Production (NHP) system. However, detailed research on the NHP system using SCBC as a power cycle has not been carried out so far and the system's thermodynamic characteristics are not well known. To fill this research gap, three promising very high-temperature gas-cooled reactor and copper-chlorine cycle-based NHP systems using different power cycles including SRC, SCBC, and combined SCBC and Organic Rankine Cycle (ORC) are proposed and studied in this work. The energy and exergy analysis method and the particle-swarm optimization algorithm have been used respectively to model and optimize the system. In addition, a parametric analysis based on two typical reactor concepts has been performed to comprehensively investigate the system's thermodynamic characteristics. Finally, a performance comparison of three systems under different hydrogen production loads has been conducted. Major results show that under different hydrogen production loads, the variations in the thermodynamic performance of the SCBC-based NHP system are sensitive to the reactor inlet temperature.Under low reactor inlet temperatures (≤587 C), the thermal efficiency of the SCBC is less than 37%. Besides, increasing the compressor pressure ratio of SCBC can enhance the system's thermodynamic performance, and the system's thermal and exergy efficiencies are improved by about 0.7% to 3.7% and 1.0% to 5.3% respectively by using ORC.

Thermohydraulic Characteristics of Printed Circuit Recuperators in a Supercritical CO2 Brayton Cycle with Nonuniform Minichannels

“…Simple design, compact layout, high thermal efficiency, acceptable cleanliness, and potential capital cost savings are the distinct advantages of this cycle [1]. Thus, it seems that the SCO 2 Brayton cycle can be used as an attractive thermal-topower system in future generations of fossil-fired plants as well as other novel plants working with waste heat recovery, concentrated solar, and nuclear power sources [2].…”

Design and analysis of an iodine‐sulfur thermochemical cycle‐based hydrogen production system with an internal heat exchange network

“…However, from the perspective of long-term development, these methods are no longer feasible because a huge amount of fossil fuels and electricity are consumed during the hydrogen production process, causing significant carbon emissions. 6 Therefore, several advanced thermochemical water-splitting cycles including the iodine-sulfur (I-S) cycle 7 and the copper-chlorine (Cu-Cl) cycle 8 are proposed and are currently being studied actively by many researchers as these cycles are very promising to achieve the large-scale carbon-free hydrogen production when they are coupled with a solar heliostat system 9 or a generation IV nuclear reactor system. 10 The I-S cycle developed by General Atomics in the 1970s is one of the most famous thermochemical watersplitting cycles and has been widely studied by many countries, 11 such as France, 12 America, 13 Japan, 14 China, 15 and Korea.…”

Integration of Supercritical CO2 Recompression Brayton Cycle with Organic Rankine/Flash and Kalina Cycles: Thermoeconomic Comparison

“…The sustainable index of the S-CO 2 cycle/subcritical ORC is 1.54, while it is 1.57 for the S-CO 2 cycle/transcritical ORC. Wang et al [19] contrasted three cycles for a nuclear hydrogen production (NHP) system: steam Rankine cycle (SRC), S-CO 2 and combined S-CO 2 /ORC. They showed that, when the inlet temperatures of the reactor in the S-CO 2 cycle are 400 • C and 587 • C, the first law efficiency of the S-CO 2 cycle varies from 27.5% to 31.0% and 27.5% to 36.5%, respectively.…”