Parametric Study of SO3 Conversion to SO2 in Tubular Reactor for Hydrogen Production via Sulfuric Cycle

Abstract

Hybrid sulfur (HyS) cycle or Westinghouse cycle is among the main candidates for full-scale solar hydrogen production. This cycle is one of the most attractive and simplest thermochemical processes, because it comprises only two global reaction steps and has only fluid reactants. The decomposition of sulfuric acid is a vital step in the sulfuric hybrid cycle process for the production of hydrogen from water. For this, the temperature needed for SO 3 to be converted into SO 2 and O 2 is very high. It requires operating temperatures above 800°C. Thus, SO 2 compound resulting from the decomposition reactor is the key compound used to feed the electrolyser where it is oxidized to regenerate H 2 SO 4 and produce H 2. This work focused on the sulfuric acid decomposition step in suggested tubular plug flow reactor with possible use of solar energy. A parametric study on the effects of temperature and pressure on the thermodynamics conversion of SO 3 to SO 2 was investigated. The theoretical sulfur trioxide conversion calculation was applied where a plug flow reactor model was assumed.