Optimization of the Westinghouse sulfur process for hydrogen generation and the interface with an HTGR

The Westinghouse Sulfur Process is a member of the sulfur family of hydrogen generating thermochemical cycles being considered by the American department of energy (DOE) for coupling with an HTGR. It has been proven experimentally and utilizes mature technology. Westinghouse has identified process improvements that increase the efficiency and reduce materials and HTGR-Hydrogen Process integration issues. Increasing the hydrogen plant operating pressure improves the thermal efficiency of the Westinghouse Sulfur Process from 40% to ∼55% (LHV basis) at H2SO4 concentrations of 40% to 80% by weight. The use of a directly heated decomposition reactor in conjunction with an HTGR allows higher decomposition reactor operating temperatures. This increases the per-pass percent conversion and increases overall efficiency. Other advantages are total separation of the coolant and process streams, the maturity of this technology (it has been used for over a century in the steel industry at temperatures up to 1200 Celsius degrees), and the ready availability of materials. (authors)