LASL bismuth sulfate thermochemical hydrogen cycle
The LASL bismuth sulfate cycle is one of a generic class of solid sulfate cycles in which a metal sulfate is substituted for sulfuric acid in a hybrid (partly electrochemical) cycle. This technique avoids the serious materials and heat penalty problems associated with the handling of concentrated acid solutions, and if the electrolyzer is operated at acid concentrations below 50% it may, in principle, lead to a lower cell voltage with subsequent energy savings. Experiment verification of all steps in the cycle has been obtained, particularly for the decomposition of normal bismuth sulfate and lower bismuth oxysulfates. For the substance, Bi/sub 2/O/sub 3/ 2SO/sub 3/, an endothermic requirement of 172 kJ/mol was obtained, which is considerably less than that for other metal sulfate systems. A rotary kiln was used for continuous experiments and our results show decomposition of this compound to Bi/sub 2/O/sub 3/ SO/sub 3/ in under 8 minutes residence time at 1023 K. Preliminary analysis of the cycle's energy balance shows an overall thermal efficiency of greater than 50% when the maximum cycle reaction temperature is 1500 K. The cycle has potential for hydrogen production when coupled with an energy source such as solar or fusion energy.
- Research Organization:
- Los Alamos Scientific Lab., NM (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5579616
- Report Number(s):
- LA-UR-80-525; CONF-800616-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
080102* -- Hydrogen-- Production-- Thermochemical Processes
BISMUTH COMPOUNDS
BISMUTH SULFATES
CRYOGENIC FLUIDS
EFFICIENCY
ELECTROLYSIS
ELEMENTS
FLUIDS
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
LYSIS
NONMETALS
OXYGEN
OXYGEN COMPOUNDS
PRODUCTION
SULFATES
SULFUR COMPOUNDS
THERMOCHEMICAL PROCESSES
WATER