Solar production of hydrogen using the sulfur-iodine thermochemical water-splitting cycle. Final report
A sulfur-sulfuric acid energy storage system is proposed for the General Atomic Company (GA) sulfur-iodine thermochemical water-splitting cycle. In this concept sulfur is burned to sulfur dioxide in air, generating the energy needed for the hydrogen production process at night and during periods of low insolation. The product of the sulfur burning reaction also provides one of the components (SO/sub 2/) of the main water-splitting reaction. Sulfur is produced from SO/sub 2/ and water in a disproportionation reaction which also produces sulfuric acid. The SO/sub 2/ is produced by the solar thermal decomposition of sulfuric acid. The energetics of burning sulfur are a good match to the energy required for running the H/sub 2/ producing plant where 1 mole of S produces 1 mole of SO/sub 2/ which produces one mole of H/sub 2/. During useful insolation periods, the H/sub 2/ producing plant is operated directly from solar energy, H/sub 2/SO/sub 4/ is concentrated, and H/sub 2/SO/sub 4/ is thermally decomposed to SO/sub 2/, O/sub 2/, and H/sub 2/O. This scheme appears to have sufficient economic benefits that it is proposed to use this storage cycle seasonally. It is expected that excess S made during the summer can be used during the winter, allowing the H/sub 2/ production plant to be levelized. It is anticipated from preliminary calculations that the H/sub 2/ production of the solar plant using this chemistry will be accomplished at a thermal efficiency of over 40%. Sizing of the solar thermochemical plant has been addressed. An average 200-MW(th) H/sub 2/ producing plant was selected. The layout of this plant has a mirror field ring surrounding a central plant. Six multipurpose receiver towers are spaced appropriately around the central plant. These features appear to make the sulfur-iodine water-splitting cycle a prime candidate for a hydrogen production process using solar thermal energy.
- Research Organization:
- General Atomic Co., San Diego, CA (USA)
- DOE Contract Number:
- AC01-80CS80004
- OSTI ID:
- 6550099
- Report Number(s):
- GA-A16493; ON: DE83005828
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
14 SOLAR ENERGY
HYDROGEN PRODUCTION
SOLAR PROCESS HEAT
THERMOCHEMICAL PROCESSES
CHEMICAL PLANTS
HEAT STORAGE
IODINE
SIZING
SULFUR
SULFUR DIOXIDE
SULFURIC ACID
THERMAL EFFICIENCY
TOWER FOCUS COLLECTORS
WATER
CHALCOGENIDES
CONCENTRATING COLLECTORS
EFFICIENCY
ELEMENTS
ENERGY
ENERGY STORAGE
EQUIPMENT
HALOGENS
HEAT
HYDROGEN COMPOUNDS
INDUSTRIAL PLANTS
INORGANIC ACIDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PROCESS HEAT
SOLAR COLLECTORS
SOLAR EQUIPMENT
STORAGE
SULFUR COMPOUNDS
SULFUR OXIDES
080102* - Hydrogen- Production- Thermochemical Processes
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
140905