A study on the dynamic behavior of a sulfur trioxide decomposer for a nuclear hydrogen production

Abstract

The sulfur–iodine thermochemical water-splitting cycle (S–I cycle) is one of the most promising technologies for mass H 2 production. The S–I cycle is generally divided into three sections, one of which involves a H 2SO 4 concentration and decomposition. In the sulfuric acid processing section (Section 2), H 2SO 4 is decomposed into H 2O and SO 3, and then the produced SO 3 is further decomposed into SO 2 and O 2, which takes place in a H 2SO 4 decomposer and a SO 3 decomposer, respectively. The SO 3 decomposition requires heat of a high temperature and this suggests a heat-exchanger type reactor. To understand the temperature profiles and chemical reactions through a SO 3 decomposer, a dynamic model was developed by considering the heat and material balances in partial differential forms. A model was used to size the decomposer to a proposed design basis and it was also applied to simulate the responses corresponding to the changes of the operation conditions such as increased or decreased flow rates.