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Synfuel (hydrogen) production from fusion power

Description: A potential use of fusion energy for the production of synthetic fuel (hydrogen) is described. The hybrid-thermochemical bismuth-sulfate cycle is used as a vehicle to assess the technological and economic merits of this potential nonelectric application of fusion power.
Date: January 1, 1979
Creator: Krakowski, R.A.; Cox, K.E.; Pendergrass, J.H. & Booth, L.A.
Partner: UNT Libraries Government Documents Department

Two bismuth sulfate-sulfuric acid hybrid thermochemical hydrogen cycles. Some experimental work related to the cycles and their possible improvement. Outline of a proposed antimonyl sulfate cycle in which sulfur dioxide and oxygen are separately evolved

Description: Thermochemical hydrogen production topics discussed include: equilibrium pressures in the decomposition of Bi/sub 2/(SO/sub 4/)/sub 3/ and ..cap alpha..-and ..beta..-Bi/sub 2/O(SO/sub 4/)/sub 2/; survey experiments on the thermal decomposition of Bi/sub 2/(SO/sub 4/)/sub 3/; hydrates sorption of H/sub 2/SO/sub 4/ solutions by the solids; and possible simplification of the SO/sub 3/-SO/sub 2/-O/sub 2/ separation problem with a sulfuric acid-antimonyl sulfate hybrid cycle.
Date: January 1, 1982
Creator: Jones, W.M.
Partner: UNT Libraries Government Documents Department

LASL thermochemical hydrogen program status on October 31, 1977. [Cycles using sulfuric acid as an intermdiate]

Description: The LASL Hydrogen Program is continuing its investigation of practical schemes to decompose water thermochemically for hydrogen production. Efforts were and are being devoted to process improvements in cycles that use sulfuric acid as an intermediate. Sulfuric acid-hydrogen bromide cycles are being studied as a means of overcoming the heat penalty in drying acid solutions. An alternate approach involves the use of insoluble bismuth sulfate that is precipitated from acid solution. Preliminary energy balances indicate a significant increase in cycle efficiency for both these options.
Date: January 1, 1977
Creator: Cox, K.E. & Bowman, M.G.
Partner: UNT Libraries Government Documents Department

LASL thermochemical hydrogen status on September 30, 1979

Description: The work described in this report was accomplished during the period October 1, 1978 to September 30, 1979. Most of the effort was applied to a study of the Los Alamos Scientific Laboratory (LASL) hybrid bismuth sulfate cycle. The work included a conceptual design of the cycle and experimental work to verify the design conditions. Key findings were: a 50.8% efficiency was obtained when an improved cycle design was coupled to a fusion energy source at 1500 K; experimental results showed an endothermic heat requirement of +172 kJ/mol for the decomposition of Bi/sub 2/O/sub 3/.2SO/sub 3/ to Bi/sub 2/O/sub 3/.SO/sub 3/, and SO/sub 3/; reaction times for bismuth sulfate decomposition were determined as a function of temperature. At 1240 K, < 1.5 min were required for the first two stages of decomposition from Bi/sub 2/O/sub 3/.3SO/sub 3/ to Bi/sub 2/O/sub 3/; tests made to determine the feasibility of decomposing Bi/sub 2/O/sub 3/.2SO/sub 3/ in a 1 inch diameter rotary kiln showed that Bi/sub 2/O/sub 3/.2SO/sub 3/ could be decomposed continuously. In related work, support was given to the DOE Thermochemical Cycle Evaluation Panel (Funk). The Second Annual International Energy Agency (IEA) Workshop on Thermochemical Hydrogen Production from Water met on September 24 to 27, 1979 at Los Alamos.
Date: January 1, 1979
Creator: Cox, K.E.
Partner: UNT Libraries Government Documents Department

LASL bismuth sulfate thermochemical hydrogen cycle

Description: 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.
Date: January 1, 1980
Creator: Cox, K.E.; Jones, W.M. & Peterson, C.L.
Partner: UNT Libraries Government Documents Department

Solids decomposition kinetics for LASL bismuth sulfate cycle

Description: The LASL Bismuth Sulfate Cycle includes a solid-decomposition step as an alternative to the high-temperature evaporation and decomposition of concentrated sulfuric acid, with its attendant drying and materials problems. A solids decomposition facility was constructed and used to study the handling of solid sulfates and the kinetics of their decomposition. The decomposition of Bi/sub 2/O(SO/sub 4/)/sub 2/ has been measured as a function of temperature and transit time through a laboratory-scale rotary kiln, constructed from quartz. Temperatures from 973 to 1143/sup 0/K were investigated. The transit time was controlled by varying the slope of the kiln, its rotational speed, and the rate of feed of a bismuth oxysulfate prepared in the prescribed manner. The preparation and characterization of this solid, which has reasonable feeding properties and minimal solution retention, are described. Significant amounts of decomposition were measured in short reaction times at the temperatures investigated.
Date: January 1, 1980
Creator: Peterson, C.L. & Bowman, M.G.
Partner: UNT Libraries Government Documents Department

Experimental work related to two bismuth sulfate cycles and their possible improvement. Outline of a possible antimonyl sulfate cycle with separate evolution of sulfur dioxide and oxygen

Description: Two bismuth sulfate cycles are made possible by the stepwise decomposition of the sulfate-oxysulfate system. Omitting statement of the steps for decomposition of SO/sub 3/ and the electrochemical formation of H/sub 2/ and H/sub 2/SO/sub 4/ from SO/sub 2/ and H/sub 2/O, the key reactions are: Cycle I - Bi/sub 2/(SO/sub 4/)/sub 3/ = Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/ + 2.3 SO/sub 3/; Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/ + 2.3 H/sub 2/SO/sub 4/ = Bi/sub 2/(SO/sub 4/)/sub 3/ + 2.3 H/sub 2/O; Cycle II - Bi/sub 2/O(SO/sub 4/)/sub 2/ = Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/ + 1.3 SO/sub 3/; Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/ + 1.3 H/sub 2/SO/sub 4/ = Bi/sub 2/O(SO/sub 4/)/sub 2/ + 1.3 H/sub 2/O. Cycle I proceeds through the intermediate oxysulfates Bi/sub 2/O(SO/sub 4/)/sub 2/ and Bi/sub 2/O/sub 2/SO/sub 4/ and Cycle II through Bi/sub 2/O/sub 2/SO/sub 4/. Cycle I has the advantage of generating 2.3 moles of H/sub 2/ per mole of Bi/sub 2/O/sub 3/, compared with 1.3 for Cycle II. Published work on the Bi/sub 2/O/sub 3/-SO/sub 3/-H/sub 2/O system shows that Bi/sub 2/(SO/sub 4/)/sub 3/ is the stable solid in contact with H/sub 2/SO/sub 4/ solutions above 52.7 wt%, so that acid of at least this strength would have to be used in Cycle I. Concentrations between about 3 wt% and 52.7 wt% could be used for Cycle II. The efficiency for electrochemical formation of H/sub 2/SO/sub 4/ and H/sub 2/ seems at present to be a maximum at around 30 wt% H/sub 2/SO/sub 4/. Some thermodynamic data obtained for the decomposition reactions are presented. A possible improvement in these cycles is also discussed which may provide a solution to a problem of sorption of H/sub 2/SO/sub ...
Date: January 1, 1981
Creator: Jones, W.M.
Partner: UNT Libraries Government Documents Department

Process design of the LASL Bismuth Sulfate thermochemical hydrogen cycle

Description: A new process engineering flowsheet reflecting an improved design of the LASL Bismuth Sulfate thermochemical cycle is presented. The design is based on laboratory data that indicate a lowered endothermic heat load for a partial decomposition of the solid bismuth sulfate. A small electrical energy demand should result from operation of the sulfur dioxide electrolytic step at lower acid concentration, in principle. The results of the flowsheeting analysis yield a thermal efficiency of 50% for the cycle when coupled to a conceptual fusion energy heat source at 1500/sup 0/K. A parametric analysis shows a slight drop in efficiency as the temperature of the heat source is decreased. The LASL Bismuth Sulfate thermochemical cycle appears to have potential as a means of producing hydrogen from high-temperature heat sources such as fusion, fission, and solar energy; it also appears to be competitive with alternative thermochemical cycles as well as with water electrolysis for hydrogen production.
Date: January 1, 1979
Creator: Cox, K.E.; Pendergrass, J.H. & Jones, W.M.
Partner: UNT Libraries Government Documents Department

Advanced thermochemical hydrogen cycles

Description: The overall objective of this program is to contribute to the development of practical thermochemical cycles for the production of hydrogen from water. Specific goals are: investigate and evaluate the technical and economic viability of thermochemical cycles as an advanced technology for producing hydrogen from water; investigate and evaluate the engineering principles involved in interfacing individual thermochemical cycles with the different thermal energy sources (high temperature fission, solar, and fusion); and conduct a continuing research and development effort to evaluate the use of solid sulfates, oxides and other compounds as potentially advanced cycles and as alternates to H/sub 2/SO/sub 4/ based cycles. Basic thermochemistry studies have been completed for two different steps in the decomposition of bismuth sulfate. Two different bismuth sulfate cycles have been defined for different sulfuric acid strengths. The eventual best cycle will depend on energy required to form sulfuric acid at different concentrations. A solids decomposition facility has been constructed and practical studies of solid decompositions are being conducted. The facility includes a rotary kiln system and a dual-particle fluidized bed system. Evaluation of different types of cycles for coupling with different heat sources is continuing.
Date: January 1, 1981
Creator: Hollabaugh, C.M. & Bowman, M.G.
Partner: UNT Libraries Government Documents Department

Alternate thermochemical cycles for advanced hydrogen production

Description: Experimental studies have validated three classes of thermochemical cycles (Bismuth sulfate-sulfuric acid, magnesium sulfate-magnesium iodide, and oxide-based) based on high temperature solids decomposition as an endothermic step. Such cycles offer the possibility of high efficiency when coupled with high temperature isothermal heat sources. Methods for handling solids in high temperature decomposition reactions have been tested. The results suggest that efficient and practical cycles can be based on such reactions.
Date: January 1, 1982
Creator: Bowman, M.G.; Hollabaugh, C.M.; Jones, W.M. & Mason, C.F.V.
Partner: UNT Libraries Government Documents Department

Alternate thermochemical cycles

Description: Experimental verification of all steps in the bismuth sulfate cycle has been obtained. At acid concentrations greater than 52.7 wt %, normal Bi/sub 2/(SO/sub 4/)/sub 3/ is formed but at lower concentrations, greater than 3.0 wt %, the bismuth oxysulfate, Bi/sub 2/O(SO/sub 4/)/sub 2/, is formed. Upon heating to temperatures in the range of 975 to 1150/sup 0/K, both decompose by the loss of SO/sub 3/ to a final composition of Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/. The higher sulfates are regenerated by reaction of this product with H/sub 2/SO/sub 4/. Solids handling and decomposition have been studied in a laboratory-scale rotary kiln and a dual-particle fluidized bed. Kiln experiments with Bi/sub 2/O(SO/sub 4/)/sub 2/, ZnSO/sub 4/, and Co/sub 3/O/sub 4/ have shown that in temperature range of 1125 to 1285/sup 0/K, over 90% decomposition occurs during the 60 s residence time. A higher temperature is required for La/sub 2/(SO/sub 4/)/sub 3/ decomposition. A dual-particle fluidized bed was constructed and tested with ZnSO/sub 4/ powder. Even with the short residence time of less than 1.0 s, over 50% decomposition is obtained at a temperature greater than 1223/sup 0/K. Cycles based on solids decomposition matches the thermal characteristics of an isothermal heat source in contrast to the H/sub 2/SO/sub 4/ cycle which best fits the heat delivery characteristics of a gas cooled reactor. A comparison has been made of the heat requirements for both H/sub 2/SO/sub 4/ and Bi/sub 2/O(SO/sub 4/)/sub 2/ decomposition and the results evaluated relative to the load line of a gas cooled reactor.
Date: January 1, 1981
Creator: Hollabaugh, C.M.; Bowman, M.G. & Peterson, C.L.
Partner: UNT Libraries Government Documents Department

Two bismuth sulfate-sulfuric acid hybrid water-splitting cycles. Proposed antimonyl sulfate cycle

Description: Some experimental work is presented that is related to two hybrid thermochemical cycles for the production of hydrogen which involve bismuth trisulfate and/or bismuth oxysulfates. Omitting statement of the steps for decomposition of SO/sub 3/ and the electrochemical formation of H/sub 2/ and H/sub 2/SO/sub 4/ from SO/sub 2/ and H/sub 2/O, the high and low temperature reactions are: Cycle I - Bi/sub 2/(SO/sub 4/)/sub 3/ = Bi/sub 2/O/sub 2/ /sub 3/ (SO/sub 4/)/sub 0/ /sub 7/ + 2.3 SO/sub 3/; and Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/ + 2.3 H/sub 2/SO/sub 4/ = Bi/sub 2/(SO/sub 4/)/sub 3/ + 2.3 H/sub 2/O. Cycle II - Bi/sub 2/O(SO/sub 4/)/sub 2/ = Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/ + 1.3 SO/sub 3/; and Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/ + 1.3 H/sub 2/SO/sub 4/ = Bi/sub 2/O(SO/sub 4/)/sub 2/ + 1.3 H/sub 2/O. Equilibrium sulfur trioxide pressures are given graphically for three solid-gas equilibria involving Bi/sub 2/(SO/sub 4/)/sub 3/, ..cap alpha..- and ..beta..-Bi/sub 2/O(SO/sub 4/)/sub 2/, and Bi/sub 2/O/sub 2/SO/sub 4/. An improved method of carrying out the low temperature step for Cycle I is presented which may provide a remedy to a problem of sorption of sulfuric acid solution by the solids. An antimonyl sulfate - sulfuric acid hybrid cycle is outlined in which SO/sub 2/ and O/sub 2/ are evolved at different temperatures, simplifying the usual SO/sub 3/-SO/sub 2/-O/sub 2/ separation problem.
Date: January 1, 1982
Creator: Jones, W.M.
Partner: UNT Libraries Government Documents Department

Solar-thermal hydrogen production

Description: Since hydrogen is not only an eventual and attractive fuel but is also a prime intermediate in the production of many fuels and chemicals, one extremely valuable utilization of a solar thermal facility would be its operation as a system for hydrogen production. Such a use would also fulfill the important requirement for energy storage. Solar thermal systems appear to offer the only practical method for significant hydrogen production from solar energy. The production could utilize advanced methods of water electrolysis if highly efficient generation of solar electricity were developed. Thermochemical cycles for water decomposition appear to be more promising if cycles that match the characteristics of solar heat sources can be developed. Advanced cycles based on solid sulfate or solid oxide decomposition reactions should interface advantageously with solar thermal systems. Sulfuric acid cycles can serve as standards of comparison for these new cycles as they are discovered and developed.
Date: January 1, 1981
Creator: Bowman, M.G.
Partner: UNT Libraries Government Documents Department

Thermochemical production of hydrogen from water, a critical review

Description: The current status of thermochemical hydrogen technology as regards process chemistry, preliminary chemical engineering design and techno-economics for a number of cycles undergoing active research and development efforts throughout the world at this time is assessed. Three cycles are receiving the bulk of the total effort and most of the funding: the hybrid sulfuric acid cycle; the sulfuric acid-hydrogen iodide cycle; and the hybrid sulfuric acid-hydrogen bromide cycle (Mark 13) . All three cycles are at the stage where a laboratory scale continuous plant can be or is in operation. The only plant in operation is at Ispra, Italy on the Mark 13 cycle. Materials problems are endemic to all cycles. In most cases reference materials for the sulfuric acid vaporization stages and the sulfuric acid or sulfur trioxide decomposition vessels have not yet been defined. A prime difficulty is the need for the vessel walls to transmit heat to interior fluids as well as withstand their corrosive effects. Serious efforts must be undertaken in the materials area prior to demonstration of any of the sulfuric acid-based cycles on a pilot plant scale under realistic pressure (30 atm) and temperature conditions. Improvements are being made in estimating the cost and efficiency of hydrogen produced from water and a thermal energy source either by thermochemical cycle technology or by water electrolysis. These include the heat penalty analysis and the OPTIMO computer code. Costs of thermochemical hydrogen have been found to fall in the $7 to $10/10/sup 16/ Btu range with efficiencies in the 35 to 45% bracket. A 10 to 15 year developmental effort with increased funding of both options (thermochemical and water electrolysis) should find a clear-cut solution and resolve the situation of the ''best'' option to use for producing synthetic hydrogen from water.
Date: January 1, 1978
Creator: Cox, K.
Partner: UNT Libraries Government Documents Department

Thermochemical processes for solar hydrogen production

Description: The use of solar energy to produce hydrogen from water is an attractive concept that merits a continuing research and development effort. The base technology being developed for solar thermal power can be applied effectively in the production of hydrogen from water. Hydrogen production could be based on advanced water electrolysis and economic solar hydrogen become an eventual reality even if advanced processes do not prove to be feasible. Thermochemical cycles for decomposing water promise higher efficiencies if cycles can be developed that match the characteristics of solar heat sources. At present, cycles based on sulfuric acid are the most fully developed processes and they can be adapted to solar thermal systems and serve as standards of comparison for new cycles as they are discovered and developed. Advanced cycles based on solids decomposition reactions should interface advantageously with solar thermal systems and several cycles based on such reactions are under experimental evaluation.
Date: January 1, 1982
Creator: Bowman, M.G.
Partner: UNT Libraries Government Documents Department

Alternate sulfate thermochemical hydrogen cycles for use with nuclear process heat

Description: The chemical reactions in the bismuth sulfate-sulfuric acid and magnesium sulfate-magnesium iodide cycles are discussed. Cycles based on solid decomposition reactions are better suited for high temperature isothermal heat sources than for gas cooled reactors. The bismuth cycle might possibly be adapted to a high temperature gas cooled system since the equilibrium dessociation pressure reaches one atmosphere at approximately 1035K and additional heat is required at lower temperatures to dry the solid and effect the low temperature reactions required to close the cycle. Two methods for conducting high temperature solid decomposition operations were tested. The first system involved a rotary kiln, which was used to study the decomposition of ZnSO/sub 4/ (to ZnO), La/sub 2/(SO/sub 4/)/sub 3/ (to La/sub 2/O/sub 2/SO/sub 4/) and Co/sub 3/O/sub 4/ (to CoO). The results of these studies, and some runs with Bi/sub 2/O(SO/sub 4/)/sub 2/ (to form Bi/sub 2/O/sub 2/ /sub 3/(SO/sub 4/)/sub 0/ /sub 7/) are tabulated. Early attempts to study Bi/sub 2/O(SO/sub 4/)/sub 2/ decomposition in a fluidized bed system were unsuccessful since these sulfate particles would not fluidize satisfactorily. Therefore, a dual-particle fluidized bed system was constructed for use with rapid, high temperature decomposition reactions. The dual-particle fluidized bed concept was tested by studies of ZnSO/sub 4/ decomposition. In these experiments, a constant flow of argon carrier gas was passed through the fluidized bed and the quantity of ZnSO/sub 4/ varied to obtain different mol ratios of carrier gas to sulfate feed. Temperatures were measured by means of a thermocouple on the exterior of the quartz tube containing the fluidized bed. The results from two series of experiments are tabulated.
Date: January 1, 1981
Creator: Bowman, M.G.
Partner: UNT Libraries Government Documents Department