US4089940A
Expired / Lapsed
US
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Process for the thermochemical production of hydrogen
Assignee: General Atomics Corp
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Filing: 1977-04-08
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Granted: 1978-05-16
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Expires: 1997-04-08
Abstract
Abstract Hydrogen is thermochemically produced from water in a cycle wherein a first reaction produces hydrogen iodide and H 2 SO 4 by the reaction of iodine, sulfur dioxide and water under conditions which cause two distinct aqueous phases to be formed, i.e., a lighter sulfuric acid-bearing phase and a heavier hydrogen iodide-bearing phase. After separation of the two phases, the heavier phase containing most of the hydrogen iodide is treated, e.g., at a high temperature, to decompose the hydrogen iodide and recover hydrogen and iodine. The H 2 SO 4 is pyrolyzed to recover sulfur dioxide and produce oxygen.
Inventors
- 👤 John H. Norman
- 👤 John L. Russell, Jr.
- 👤 II John T. Porter
- 👤 Kenneth H. McCorkle
- 👤 Thomas S. Roemer
- 👤 Robert Sharp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:53
CPC Classifications
C; C01; C01B; C01B3/00; C01B3/02; C01B3/06; C01B3/103; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/36
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
134 words
A process for the thermochemical production of hydrogen from water, which process comprises the steps of making hydrogen iodide and H 2 SO 4 by the reaction of iodine, sulfur dioxide and water, said reaction being carried out with sulfur dioxide and iodine present in stoichiometric excess with respect to the reacting water and at a temperature above about -60° C. to cause two distinct aqueous phases to be formed, a lighter sulfuric acid-bearing phase and a heavier hydrogen iodidebearing phase, said lighter phase containing most of said H 2 SO 4 which is produced and said heavier phase containing most of said hydrogen iodide which is produced, separating said heavier phase from said lighter phase, treating said hydrogen iodide from said heavier phase to cause the decomposition thereof and recovering hydrogen and iodine.
Claim 2
Dependent Claim
134 words
A process for the thermochemical production of hydrogen from water, which process comprises the steps of making hydrogen iodide and H 2 SO 4 by the reaction of iodine, sulfur dioxide and water, said reaction being carried out with sulfur dioxide and iodine present in stoichiometric excess with respect to the reacting water and at a temperature above about -60° C. to cause two distinct aqueous phases to be formed, a lighter sulfuric acid-bearing phase and a heavier hydrogen iodidebearing phase, said lighter phase containing most of said H 2 SO 4 which is produced and said heavier phase containing most of said hydrogen iodide which is produced, separating said heavier phase from said lighter phase, treating said hydrogen iodide from said heavier phase to cause the decomposition thereof and recovering hydrogen and iodine.
Claim 3
Dependent Claim
26 words
A process in accordance with claim 1 wherein said reaction is carried out employing an amount of iodine sufficient to substantially saturate said heavier aqueous phase.
Claim 4
Dependent Claim
27 words
A process in accordance with claim 1 wherein sulfur dioxide is provided in an amount sufficient to substantiallly saturate said heavier aqueous phase at the delivery pressure.
Claim 5
Dependent Claim
25 words
A process in accordance with claim 1 wherein said reaction is carried out at a temperature of between about 20° C. and about 120° C.
Claim 6
Dependent Claim
33 words
A process in accordance with claim 4 with said reaction being carried out under conditions wherein at least 44 grams of iodine are provided for each 15 grams of water which are provided.
Claim 7
Dependent Claim
32 words
A process in accordance with claim 1 wherein the reactants are fed continuously to a reaction zone and wherein said lighter phase and said heavier phase are continuously separated from each other.
Claim 8
Dependent Claim
35 words
A process in accordance with claim 1 wherein said reactants are continuously fed to a reaction vessel and wherein batches of said heavier phase and said lighter phase are removed and separated from each other.
Claim 9
Dependent Claim
39 words
A process in accordance with claim 1 wherein said separated lighter phase is first distilled to remove hydrogen iodide, iodine and water and the remainder is thermally decomposed to form sulfur dioxide, water and oxygen in a vapor-phase reaction.
Claim 10
Dependent Claim
33 words
A process in accordance with claim 8 wherein recuperative cooling is carried out in combination with said vapor-phase decomposition so as to recover sulfur dioxide and water by condensation without significant recombination thereof.
Claim 11
Dependent Claim
41 words
A process in accordance with claim 1 wherein said separated heavier phase is distilled to produce hydrogen iodide in a substantially dry condition and wherein said dry hydrogen iodide is pyrolyzed in a reaction chamber to produce gaseous hydrogen and iodine.
Claim 12
Dependent Claim
29 words
A process in accordance with claim 10 wherein said iodine is separated from said reaction chamber by maintaining isothermal conditions such that iodine condenses in situ upon its creation.
Claim 13
Dependent Claim
139 words
In a process for the production of hydrogen from water, wherein H 2 O, SO 2 and I 2 are reacted to produce sulfuric acid and hydrogen iodide and wherein hydrogen is recovered from said hydrogen iodide following further treatment thereof, wherein the improvement comprises carrying out said reaction at a temperature above about -60° C. with sulfur dioxide and iodine present in a stoichiometric excess with respect to the reacting water so as to cause two distinct aqueous phases to be formed, a lighter sulfuric acid-bearing phase and a heavier hydrogen iodide-bearing phase, said lighter phase containing most of said sulfuric acid which is produced and said heavier phase containing most of said hydrogen iodide which is produced, and separating said heavier phase from said lighter phase before treating said hydrogen iodide to effect said recovery of hydrogen.
Claim 14
Dependent Claim
139 words
In a process for the production of hydrogen from water, wherein H 2 O, SO 2 and I 2 are reacted to produce sulfuric acid and hydrogen iodide and wherein hydrogen is recovered from said hydrogen iodide following further treatment thereof, wherein the improvement comprises carrying out said reaction at a temperature above about -60° C. with sulfur dioxide and iodine present in a stoichiometric excess with respect to the reacting water so as to cause two distinct aqueous phases to be formed, a lighter sulfuric acid-bearing phase and a heavier hydrogen iodide-bearing phase, said lighter phase containing most of said sulfuric acid which is produced and said heavier phase containing most of said hydrogen iodide which is produced, and separating said heavier phase from said lighter phase before treating said hydrogen iodide to effect said recovery of hydrogen.
Claim 15
Dependent Claim
29 words
A process in accordance with claim 12 wherein iodine is present in an amount equal to at least about 2 grams per each gram the total amount of water.
Claim 16
Dependent Claim
19 words
A process is accordance with claim 12 wherein said iodine is present in at least a near saturation amount.
Claim 17
Dependent Claim
26 words
A process in accordance with claim 12 wherein said reaction is carried out under a pressure of SO 2 equal to at least about 1 atmosphere.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1981-05-15 | 1981-11-14 | 1982-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-15 | 1985-11-14 | 1986-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-15 | 1989-11-14 | 1990-05-16 | $7700.00 | Window Closed / Lapsed |