Patent US4244794A successfully refreshed from Google Patents.
← Back to Patent Explorer
US4244794A Expired / Lapsed US ⏱️ 0.0 years remaining

Hydrogen production by the decomposition of water

Assignee: United States Department of Energy
•
Filing: 1979-07-31
•
Granted: 1981-01-13
•
Expires: 1999-07-31
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract How to produce hydrogen from water was a problem addressed by this invention. The solution employs a combined electrolytical-thermochemical sulfuric acid process. Additionally, high purity sulfuric acid can be produced in the process. Water and SO2 react in electrolyzer (12) so that hydrogen is produced at the cathode and sulfuric acid is produced at the anode. Then the sulfuric acid is reacted with a particular compound MrXs so as to form at least one water insoluble sulfate and at least one water insoluble oxide of molybdenum, tungsten, or boron. Water is removed by filtration; and the sulfate is decomposed in the presence of the oxide in sulfate decomposition zone (21), thus forming SO3 and reforming MrXs. The MrXs is recycled to sulfate formation zone (16). If desired, the SO3 can be decomposed to SO2 and O2; and the SO2 can be recycled to electrolyzer (12) to provide a cycle for producing hydrogen.

Inventors

  • 👤 Charles M. Hollabaugh
  • 👤 Melvin G. Bowman

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 14:12
CPC Classifications
C; C25; C25B; C25B1/00; C25B1/01; C25B1/22; C25B1/02; C25B1/04; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/36; Y02P; Y02P20/00; Y02P20/10; Y02P20/129

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 267 words
A process for producing hydrogen comprising: (1) passing an electric current from a cathode to an anode through water containing sulfur dioxide so as to produce hydrogen gas at the cathode and so as to oxidize the sulfur dioxide to form sulfuric acid at the anode, thus producing an aqueous solution of sulfuric acid; (2) separating said hydrogen gas from said aqueous solution of sulfuric acid; (3) adding to said aqueous solution of sulfuric acid at least one compound selected from the group consisting of M r X s , wherein M is at least one metal ion selected from the group consisting of Ba +2 , Ca +2 , Sr +2 , La +3 , and Pb +2 , wherein X is at least one radical selected from the group consisting of molybdate, tungstate, and metaborate, wherein r is an integer selected from the group consisting of 1 and 2, wherein s is an integer selected from the group consisting of 1, 2, and 3, producing a mixture of at least one water insoluble sulfate of M and at least one water insoluble oxide of molybdenum, tunsten, or boron; (4) filtering said mixture of water insoluble sulfate and water insoluble oxide; (5) heating said mixture of water insoluble sulfate and water insoluble oxide to a sulfate decomposition temperature which is sufficiently high to form sulfur trioxide gas and to reform said M r X s ; (6) separating said sulfur trioxide gas from said M r X s which was reformed in step (5); and (7) recycling said M r X s to step (3) above.
Claim 2
Dependent Claim 267 words
A process for producing hydrogen comprising: (1) passing an electric current from a cathode to an anode through water containing sulfur dioxide so as to produce hydrogen gas at the cathode and so as to oxidize the sulfur dioxide to form sulfuric acid at the anode, thus producing an aqueous solution of sulfuric acid; (2) separating said hydrogen gas from said aqueous solution of sulfuric acid; (3) adding to said aqueous solution of sulfuric acid at least one compound selected from the group consisting of M r X s , wherein M is at least one metal ion selected from the group consisting of Ba +2 , Ca +2 , Sr +2 , La +3 , and Pb +2 , wherein X is at least one radical selected from the group consisting of molybdate, tungstate, and metaborate, wherein r is an integer selected from the group consisting of 1 and 2, wherein s is an integer selected from the group consisting of 1, 2, and 3, producing a mixture of at least one water insoluble sulfate of M and at least one water insoluble oxide of molybdenum, tunsten, or boron; (4) filtering said mixture of water insoluble sulfate and water insoluble oxide; (5) heating said mixture of water insoluble sulfate and water insoluble oxide to a sulfate decomposition temperature which is sufficiently high to form sulfur trioxide gas and to reform said M r X s ; (6) separating said sulfur trioxide gas from said M r X s which was reformed in step (5); and (7) recycling said M r X s to step (3) above.
Claim 3
Dependent Claim 58 words
A method according to claim 1 and including also the steps of decomposing said sulfur trioxide gas by heating to a sufficiently high temperature to re-form sulfur dioxide and to form oxygen gas by heating to a sufficiently high temperature to re-form sulfur dioxide and to form oxygen gas and then separating said sulfur dioxide from said oxygen.
Claim 4
Dependent Claim 27 words
A method according to claim 2 and including also the step of recycling to step (1) said sulfur dioxide which was formed by decomposing said sulfur trioxide.
Claim 5
Dependent Claim 31 words
A method according to claim 3 or claim 1 wherein said sulfate decomposition temperature is sufficiently high to melt said water insoluble oxide in the presence of said water insoluble sulfate.
Claim 6
Dependent Claim 23 words
A method according to claim 4, wherein said aqueous solution of sulfuric acid had a sulfuric acid concentration less than about 1 molar.
Claim 7
Dependent Claim 46 words
A method according to claim 5 and including also the step of drying said mixture of water insoluble sulfate and water insoluble oxide after it has been filtered and before it is heated to said sulfate decomposition temperature, so as to remove water from said mixture.
Claim 8
Dependent Claim 43 words
A method according to claim 6, wherein said radical is molybdate, wherein M is selected from the group consisting of Ba +2 and Ca +2 , and wherein said sulfate decomposition temperature is within the range from about 1125° to about 1275° K.
Claim 9
Dependent Claim 43 words
A method according to claim 3, wherein said radical is molybdate, wherein M is selected from the group consisting of Ba +2 and Ca +2 , and wherein said sulfate decomposition temperature is within the range from about 1125° to about 1275° K.
Claim 10
Dependent Claim 40 words
A method of producing concentrated sulfuric acid and hydrogen gas comprising the method according to claim 1 and including also the step of dissolving said sulfur trioxide in a small amount of water so as to produce concentrated sulfuric acid.
Claim 11
Dependent Claim 46 words
A method according to claim 1 and including also the step of drying said mixture of water insoluble sulfate and water insoluble oxide after it has been filtered and before it is heated to said sulfate decomposition temperature, so as to remove water from said mixture.

References Cited (Backward Citations)

US704831A Cited
US3888750A Cited
US4089940A Cited
US4059496A Cited
US4080436A Cited
US4089939A Cited
US4127644A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1984-01-13 1984-07-14 1985-01-13 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1988-01-13 1988-07-14 1989-01-13 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1992-01-13 1992-07-14 1993-01-13 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag