Hybrid sulfur cycle flowsheets for hydrogen production using high-temperature gas-cooled reactors

• Published in: International journal of hydrogen energy Vol. 36; no. 20; pp. 12725 - 12741
• Main Author: Gorensek, Maximilian B.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2011; Elsevier
• Subjects: 08 HYDROGEN; Alternative fuels. Production and utilization; Applied sciences; Aspen Plus; Bayonet decomposition reactor; Decomposition reactions; ELECTROLYSIS; Energy; ENERGY BALANCE; Exact sciences and technology; FLOWSHEETS; Fuels; HEATING; Hybrid sulfur cycle; Hydrogen; HYDROGEN PRODUCTION; MEMBRANES; Nuclear engineering; Nuclear power generation; Nuclear reactor components; Nuclear reactors; Polybenzimidazoles; Process flowsheet; Proton exchange membrane electrolyzer; PROTONS; Silicon carbide; SILICON CARBIDES; SULFUR; SULFUR CYCLE; THERMAL EFFICIENCY; Process flowsheet; Proton exchange membrane electrolyzer; Aspen Plus; Hybrid sulfur cycle; Hydrogen production; Bayonet decomposition reactor; Hydrogen; High temperature; Proton exchange membrane elec trolyzer; Energy balance; Project; Electrolysis; Membrane; Silicon; Thermal efficiency; Performance; Sulfur; Proton exchange
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2011.07.033

Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO 2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 °C, the other 750 °C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2′-( m-phenylene)-5,5′-bibenzimidazole] (PBI), instead of Nafion ®, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0–47.6%, higher heating value basis is projected for the 950 °C case, dropping to 39.9% for the 750 °C case. ► Two hybrid sulfur cycle flowsheets are presented that combine a bayonet decomposition reactor with a proton exchange membrane electrolyzer. ► Aspen Plus material and energy balances are provided. ► One flowsheet can be used with a 950 °C reactor to make hydrogen at 44.0–47.6% net thermal efficiency, HHV basis. ► The other flowsheet can be used with a 750 °C reactor to make hydrogen at 39.9% net thermal efficiency, HHV basis.