Sulfuric acid decomposition in the iodine–Sulfur cycle using heat from a very high temperature gas-cooled reactor

The key interface component between the reactor and chemical systems for the sulfuric acid based processes to make hydrogen is the sulfuric acid decomposition reactor. The materials issues for the decomposition reactor are severe since sulfuric acid must be heated, vaporized and decomposed. SiC has been identified and proven by others to be an acceptable material. However, SiC has a significant design issue when it must be interfaced with metals for connection to the remainder of the process. Westinghouse has developed a design utilizing SiC for the high temperature portions of the reactor that are in contact with the sulfuric acid and polymeric coated steel for low temperature portions. This design is expected to have a reasonable cost for an operating lifetime of 20 years. It can be readily maintained in the field, and is transportable by truck (maximum OD is 4.5 meters). This paper summarizes the detailed engineering design of the Westinghouse Decomposition Reactor and the decomposition reactor’s capital cost.

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Catalytic activities of cobalt, nickel and copper ferrospinels for sulfuric acid decomposition: The high temperature step in the sulfur based thermochemical water splitting cycles

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2011.01.073 ◽

2011 ◽

Vol 36 (8) ◽

pp. 4768-4780 ◽

Cited By ~ 70

Author(s):

A.M. Banerjee ◽

M.R. Pai ◽

S.S. Meena ◽

A.K. Tripathi ◽

S.R. Bharadwaj

Keyword(s):

Sulfuric Acid ◽

High Temperature ◽

Water Splitting ◽

Temperature Step ◽

Acid Decomposition ◽

Catalytic Activities ◽

Cobalt Nickel ◽

Sulfuric Acid Decomposition

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Structural Design Simulation of Bayonet Heat Exchanger for Sulfuric Acid Decomposition

Energies ◽

10.3390/en14020422 ◽

2021 ◽

Vol 14 (2) ◽

pp. 422

Author(s):

Qunxiang Gao ◽

Ping Zhang ◽

Wei Peng ◽

Songzhe Chen ◽

Gang Zhao

Keyword(s):

Heat Transfer ◽

Sulfuric Acid ◽

Decomposition Rate ◽

Structural Design ◽

Catalytic Domain ◽

Transport Model ◽

Fluid Velocity ◽

Sulfur Cycle ◽

Acid Decomposition ◽

Sulfuric Acid Decomposition

The heat generated in a high-temperature gas-cooled reactor can be used to drive the iodine-sulfur cycle to produce hydrogen. However, the sulfuric acid decomposition step requires a sophisticated sulfuric acid decomposer to increase the decomposition rate. The decomposition of sulfuric acid mainly occurs in the catalytic zone, and the optimization of its structure is very important for increasing the decomposition rate. This study focuses on the structural design of the catalytic zone of the sulfuric acid decomposer unit. The structure with double inner tubes is designed to analyze the influence of the inner tube heat transfer area and the catalytic volume of the annulus region on the decomposition rate. The species transport model is used to predict the proportion of products followed by analysis of the key factors affecting the decomposition rate of the catalytic domain. The results reveal that the new design attains the decomposition temperature requirements and increases the fluid velocity of the inner tube. This in turn promotes the heat transfer effect. The decomposition rate is negatively correlated with the flow rate. Nonetheless, a structure with double inner tubes which have the same total area of inner tube as a structure with a single inner tube has a better optimization effect than a structure which has the same annulus catalytic volume as a structure with single inner tube. It increases the decomposition rate by up to 6.1% while a structure which has the same annulus catalytic volume as a structure with a single inner tube does the same by up to 1.7%. The decomposition rate can be maintained at a relatively high level when the inlet velocity of the current structural design is about 0.2 m/s. This study provides a reference for the engineering design of sulfuric acid decomposer based on the heat exchange area and catalytic volume.

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