&nbsp; &nbsp; The high-temperature gas-cooled reactor is a fourth-generation reactor with inherent safety and modular high-temperature characteristics. It can provide ultra-high temperature heat of 850℃ and can be used in a variety of process heat utilization methods. Hydrogen production can solve the energy crisis and achieve sustainable development, which is one of the mainstream options and has great development potential. The main methods of using nuclear energy to produce hydrogen are methane steam reforming and iodine-sulfur cycle, both of which have their own advantages, but the iodine-sulfur cycle does not produce greenhouse gases and has higher hydrogen production efficiency, which is an important development direction for hydrogen production.&nbsp; &nbsp; A key link in the iodine-sulfur cycle is the decomposition of hydroiodic acid, which determines the hydrogen production efficiency of the entire thermochemical cycle system. The decomposition of hydroiodic acid is usually carried out in an adiabatic reactor. The whole process only relies on the heat of hydroiodic acid to complete the decomposition, and does not rely on other heat sources. Due to the special structure of the adiabatic reactor, the existing engineering research is insufficient, and the optimization design of its structure is even rarer. Therefore, designing the structure of the adiabatic reactor and calculating the distribution of various internal physical fields are of great significance to the decomposition of hydroiodic acid.&nbsp; &nbsp; In this paper, numerical simulations are performed on the adiabatic reactor used for the decomposition of hydroiodic acid. The species transport model, volume reaction and porous model are used to calculate the temperature field, flow field, pressure drop and the distribution of each component.The results show that, under the current design flow, the temperature of hydroiodic acid is reduced by about 30 K, but the temperature is always maintained at a level above 800 K, which can meet the temperature requirement for decomposition. The maximum yield of hydrogen can reach 24%, and the distribution is uniform. The results of this study can provide theoretical calculation references for the engineering application of adiabatic reactors.

Numerical Simulation of Hi Thermal Decomposer in Iodine-Sulfur Cycle Process

Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE28/volume/85246

2021 28th International Conference on Nuclear Engineering (ICONE28)

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