Thermodynamic analysis of a novel hydrogen-electricity-heat polygeneration system based on a very high-temperature gas-cooled reactor

Nuclear energy can offer clean, efficient, and large-scale hydrogen production, and a polygeneration system can meet multi-level energy demands. In this study, a novel polygeneration system coupled with a very high-temperature gas-cooled reactor is proposed for realizing the cascade utilization of energy. High-grade heat is used for the high-temperature processes of hydrogen production, and low-grade heat is used for the low-temperature processes of hydrogen production, electricity generation, and process heat extraction. The system can output hydrogen, electricity, and high-temperature steam simultaneously. Process simulation of iodine-sulfur cycle is performed to obtain heat duty of each component in hydrogen production process. Energy and exergy analyses are used to analyze thermodynamic performance of the system. The power ratio (PR) of electricity generation to hydrogen production and the share of the main steam extracted for heat supply (aSTSR) are two important parameters for determining energy distribution of the system, and the overall energy and exergy efficiencies of the system reach 51.27% and 66.96%, respectively, when PR =1 and aSTSR = 0.15. The sulfuric-acid concentration tower has the largest exergy loss coefficient of 8.89%, followed by steam generator of 7.04%. These are crucial components for improving thermodynamic performance of the system. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study proposes a polygeneration system coupled with a very high-temperature gas-cooled reactor for the cascading utilization of energy. The system simultaneously outputs hydrogen, electricity, and high-temperature steam. Energy and exergy analyses reveal that the overall energy and exergy efficiencies reach 51.27% and 66.96%, respectively, when the power ratio is 1 and the share of the main steam extracted for heat supply is 0.15.