Sulfuric acid process, production hybrid

Figure 12. Production cost vs. process efficiency for hybrid sulfuric acid process...

Knoche, K.F. and Funk, J.E., "Entropy Production, Efficiency, and Economics in the Thermochemical Generation of Synthetic Fuels. I. The Hybrid Sulfuric Acid Process, Int. J. Hydrogen Energy 2, No. 4, 377-386 (1977). 

K. F. Knoche, J. E. Funk Entropy production, efficiency and economics in the thermochemical generation of synthetic fuels. I. The hybrid sulfuric acid process, Int. J. of Hydrogen Energy, 29 (1977) 23-27 Brennst.-Warme-Kraft 29 (1977) 2i-21. 

Many types of thermochemical processes for H2 production exist. All of the competitive processes require heat input at temperatures above 750°C. The sulfuric acid processes (sulfur-iodine and Westinghouse hybrid) are the leading candidates. In each of these processes, the high-temperature, low-pressure endothermic (heat-absorbing) reaction is the catalytic thermal decomposition of sulfuric acid to produce oxygen ... 

The Hybrid Sulfur (HyS) thermochemical cycle task addresses the key technology issues involved in the development of a hybrid sulfur hydrogen production system - including the SO2 - H2O electrolyzer design, SO2/O2 separation, and the unique materials and process issues associated with the acid decomposition section. An electrolyser is being developed that can be used in conjunction with the sulfuric acid decomposition section being developed for the S-I cycle in a Hybrid Sulfur Integrated Laboratory-Scale Experiment. 

The thermochemical and electrolytic hybrid hydrogen production process has been developed by Japan Nuclear Cycle Development Institute (JNC). The process is based on sulfuric acid (H2SO4) syntliesis and decomposition process developed earlier (Westinghouse process) and sulfur trioxide (SO,) decomposition process is facilitated by electrolysis with ionic oxygen conductive solid electrolyte at 500°C-550°C. Stable hydrogen and oxygen production for several hours by the process was already confirmed in the experiments performed by JNC. 

An effluent stream of 3 m /h containing 7.6 gd of sodium sulfate at 20 C is treated in a hybrid process reverse osmosis for concentration and production of clean process water and membrane electrolysis for the conversion of sodium sulfate into sulfuric acid (15%) and caustic soda which is used for neutralisation. 

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