Thermal design of a laboratory—scale SO3 decomposer for nuclear hydrogen production

Designing of a sulfur trioxide decomposer is one of the main technical challenges in the development of a nuclear hydrogen production system. Korea Atomic Energy Research Institute (KAERI) has developed a hybrid-design decomposer to withstand the severe operating conditions. In this design, the hot gas side is equipped with printed circuit-type heat exchangers (PCHE), and the process gas side is equipped with plate fin-type heat exchangers (PFHE). In this study, the sensitivity analysis is performed to estimate the effects of the various factors on the thermal design of a sulfur trioxide decomposer for its performance test in a small-scale gas loop. The principal factors affecting the decomposer's thermal design are categorized into four groups: rate constants, geometrical parameters, heat transfer parameters, and operating conditions. Our results indicate that the rate constant of the catalyzed reaction and the decomposer retention time are the most important factors dictating the thermo-chemical behavior of the sulfur trioxide decomposer. The information obtained from this analysis will serve to guide the manufacture and operation of this laboratory-scale decomposer.