Reactor-membrane permeator process for hydrocarbon reforming and water gas-shift reactions

• US 6,090,312 A
• Filed: 01/31/1996
• Issued: 07/18/2000
• Est. Priority Date: 01/31/1996
• Status: Expired due to Fees

• Current Assignee: Savvas Vasileiadis, Zoe D. Ziaka
• Original Assignee: Savvas Vasileiadis, Zoe D. Ziaka
• Inventors: Vasileiadis, Savvas, Ziaka, Zoe D.
• Primary Examiner(s): PADMANABHAN, SREENIVASAN
• Application Number:
  US08/595,040
• Time in Patent Office: 1,630 Days
• Field of Search: 423/650, 423/652, 423/418.2, 95/41, 252/373, 252/376, 518/700, 518/703, 518/728, 44/457, 44/530, 44/591
• US Class Current: 252/373
• CPC Class Codes: C01B 2203/0233 the reforming step being a steam reforming step
• CPC Class Codes: C01B 2203/0238 the reforming step being a carbon dioxide reforming step
• CPC Class Codes: C01B 2203/0283 containing a CO-shift step, i.e. a water gas shift step
• CPC Class Codes: C01B 2203/0288 containing two CO-shift steps
• CPC Class Codes: C01B 2203/0405 Purification by membrane separation
• CPC Class Codes: C01B 2203/042 Purification by adsorption on solids
• CPC Class Codes: C01B 2203/046 Purification by cryogenic separation
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/0495 the impurity being water
• CPC Class Codes: C01B 2203/06 Integration with other chemical processes
• CPC Class Codes: C01B 2203/061 Methanol production
• CPC Class Codes: C01B 2203/062 Hydrocarbon production, e.g. Fischer-Tropsch process
• CPC Class Codes: C01B 2203/066 with fuel cells
• CPC Class Codes: C01B 2203/068 Ammonia synthesis
• CPC Class Codes: C01B 2203/0811 by combustion of fuel
• CPC Class Codes: C01B 2203/0883 by indirect heat exchange
• CPC Class Codes: C01B 2203/0894 Generation of steam
• CPC Class Codes: C01B 2203/1211 Organic compounds or organic mixtures used in the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 2203/1223 Methanol
• CPC Class Codes: C01B 2203/1229 Ethanol
• CPC Class Codes: C01B 2203/1241 : Natural gas or methane
• CPC Class Codes: C01B 2203/1294 : Evaporation by heat exchange with hot process stream
• CPC Class Codes: C01B 2203/142 : At least two reforming, decomposition or partial oxidation steps in series
• CPC Class Codes: C01B 2203/147 : Three or more purification steps in series
• CPC Class Codes: C01B 2203/148 : involving a recycle stream to the feed of the process for making hydrogen or synthesis gas
• CPC Class Codes: C01B 2203/84 : Energy production
• CPC Class Codes: C01B 3/48 : followed by reaction of water vapour with carbon monoxide
• CPC Class Codes: C01B 3/501 : by diffusion
• CPC Class Codes: C07C 29/1518 : one step being the formation of initial mixture of carbon oxides and hydrogen for synthesis
• CPC Class Codes: C07C 31/04 : Methanol
• CPC Class Codes: H01M 8/0612 : from carbon-containing material
• CPC Class Codes: H01M 8/0662 : Treatment of gaseous reactants or gaseous residues, e.g. cleaning
• CPC Class Codes: Y02E 50/10 : Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 : Fuel from waste, e.g. synthetic alcohol or diesel
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y02P 20/582 : Recycling of unreacted starting or intermediate materials
• CPC Class Codes: Y02T 50/678 : Aviation using fuels of non-fossil origin

Abstract

New process designs are presented for reforming reactions of steam with hydrocarbons (such as methane, natural gas, light hydrocarbon feedstocks with one to four carbon atoms in each molecule), also for the water gas shift reaction that is of steam with carbon monoxide; also for carbon dioxide reforming of hydrocarbons (such as methane, acidic natural gas, coal gas, landfill gas, light hydrocarbon feedstocks with one to four carbon atoms in each molecule), and the combined reaction of steam carbon dioxide with same hydrocarbons. The processes employ organic polymer, organic polymer-inorganic support, and inorganic membrane permeators for species separation, with the permeators placed after the reactors where the above named reactions take place. The membranes in permeators separate selectively the H₂ and CO₂ species exiting from the reactors from the non-permeated reactants and products. The reject streams coming out of permeators can be recycled into the inlet of the first reactors; these reject streams can be also fed to consecutively placed steam reforming and water gas shift reactors for further conversion to H₂ and CO₂ products. The separated H₂ and CO₂ in membrane permeate and from the secondary reactions of permeator reject streams, can be used for direct methanol synthesis, feed to molten carbonate fuel cells, and other chemical syntheses; after the removal of CO₂ from the mixture, pure hydrogen can be recovered and used in chemical syntheses and as fuel in fuel cells and power generation cycles.

Claims

1. A process that reforms a hydrocarbon with steam (H₂ O(g)) over a bed of metallic catalyst in a steam reforming reactor to produce H₂, CO₂ and CO by the hydrocarbon steam reforming and water gas shift reactions, with the exit stream to be passed through a heat exchanger to reduce its temperature and condense the unreacted steam by generating new steam in other side of the exchanger to be used as feed into this reforming reactor and any subsequently placed reformer, with the remaining gas mixture to remove moisture traces by passage through a bed of moisture adsorbing particles, with the dry cooled exit mixture from the particle bed to enter into a membrane permeator made by one of the following materials,

organic polymer membrane,

organic polymer membrane-inorganic support,

inorganic membrane,

which all materials are permselective to H₂ and CO₂ and separate these two species from the unreacted hydrocarbon and CO, with these last non-permeating compounds to exit from the non-permeate side of the permeator as a reject stream, with the H₂ and CO₂ permeate product mixture to be used for

chemical synthesis and

as fuel either as is a mixture or as pure H₂ after the CO₂ condensation and removal.

2. The process of claim 1 wherein the hydrocarbon is a single constituent or a mixture of constituents of the following components

methane,

ethane,

propane,

n-butane,

i-butane,

methanol,

ethanol,

natural gas rich in methane,

coal gas rich in methane,

landfill gas rich in methane,

flue gas rich in methane.

3. The process of claim 1 wherein the membrane in permeator is made from an organic polymer or composite or copolymer of organic polymers selected from the group of

polyimides,

polycarbonates,

polysulfones,

polybenziimidazoles,

polyphosphazenes,

polyamides,

polystyrenes,

polycaprolactams,

parylenes,

polyvinyl halides,

polyacetates,

polysiloxanes

or from inorganic-metal composites based on pure or mixture of one of the following ceramic oxides:

alumina (Al₂ O₃),

titania (TiO₂),

silica (SiO₂),

zirconia (ZrO₂).

4. The process of claim 1 with the reject stream from the permeator containing unreacted CO and hydrocarbon to be recycled into the inlet of the first reformer for continuous steam reforming and water gas shift reactions in the reformer.

5. The process of claim 1 with the reject stream from the permeator containing unreacted hydrocarbon and CO to enter into a consecutively placed steam reformer to react with steam over a bed of metallic catalyst via the steam reforming and water gas shift reactions and be converted into H₂ and CO₂ product, having this exit stream from last reformer to condense its unreacted steam by passage through a heat exchanger and by generating new steam in other side of the heat exchanger to be used as feed in the inlet of the last reformer, having the final exit dry mixture of H₂ and CO₂ from the heat exchanger to be combined with the permeate from the membrane permeator, H₂ and CO₂ stream, to make one combined stream of H₂ and CO₂ to be used for

chemical synthesis,

also as fuel

either as a mixture or as pure H₂ after the CO₂ condensation and removal.

6. The process of claim 5 wherein the combined H₂ and CO₂ product mixture is used

(a) for direct methanol synthesis via the reaction:

CO₂ +3H₂ ═

CH₃ OH(g)+H₂ O(g),

(b) for direct feed in molten carbonate fuel cell (MCFC) units for electricity generation via the overall electrochemical reaction;

H₂ +CO₂ +1/2O₂ (cathode)→

H₂ O+CO₂ (anode),

(c) for other CO₂ and H₂ or H₂ only chemical synthesis reactions, moreover after the removal of CO₂ pure H₂ is used

(d) as fuel in the anode of fuel cells such as phosphoric acid, alkaline, molten carbonate, solid oxide, proton exchange,

(e) and as fuel in gas turbines, conventional and jet type gas engines.

7. The process of claim 1 with the hydrocarbon in stream 1 to be replaced by carbon monoxide (CO) to react with steam in reactor A via only the water gas shift reaction, with the exit from reactor stream to contain products H₂, CO₂ and unreacted CO and steam, having steam condensation and removal of moisture content in heat exchanger and moisture adsorbing particle bed, having the H₂ and CO₂ separated in the consecutive membrane permeator and the CO exiting from the non-permeate side of the permeator as reject stream, with the H₂ and CO₂ mixture permeated from membrane permeator to be used for

chemical synthesis,

also as fuel

either as a mixture or as pure H₂ after the CO₂ condensation and removal.

8. The process of claim 7 with the reject stream from the permeator containing the unreacted CO to be recycled into inlet of first water gas shift reactor for continuous reaction into the reactor.

9. The process of claim 7 with the reject stream from the permeator containing unreacted CO to enter into a consecutive placed water gas shift reactor to react with steam over a bed of metallic catalyst via the water gas shift reaction and be converted into H₂ and CO₂ product, having the exit stream from last shift reactor to condense its unreacted steam by passage through a heat exchanger and by generating new steam in the other side of the heat exchanger to be used as feed in the inlet of this last shift reactor in an autothermic operation, having the final exit dry mixture of H₂ and CO₂ from last heat exchanger to be combined with the permeate from the membrane permeator, H₂ and CO₂ stream, to make one combined stream of H₂ and CO₂ to be used for

chemical synthesis,

also as fuel

either as a mixture or as pure H₂ after the CO₂ condensation and removal.

10. A process that reacts a hydrocarbon with CO₂ and steam (H₂ O(g)) over a bed of metallic catalyst in a steam and CO₂ reforming reactor to produce H₂ and CO via the hydrocarbon steam reforming reaction, the hydrocarbon CO₂ reforming reaction, and the reverse water gas shift reaction, with the exit stream to be passed through a heat exchanger to reduce its temperature and condense unreacted and produced steam by generating new steam in other side of the exchanger which is used as feed into this reforming reactor and any subsequently placed reformer, with the exit stream from the heat exchanger to be passed through a bed of moisture adsorbing particles to remove any moisture content, with the dry cooled exit gas mixture to enter into a membrane permeator made by one of the following materials,

organic polymer membrane,

organic polymer membrane-inorganic support,

inorganic membrane,

which all materials are permselective to H₂ and CO₂ and separate these two species in permeate stream from the unreacted hydrocarbon and product CO which exit from the non-permeate side of the permeator as a reject stream, with the H₂ and CO₂ permeate product mixture to be used for

chemical synthesis,

also as fuel

either as a mixture or as pure H₂ after the CO₂ condensation and removal.

11. The process of claim 10 with the reject stream from the permeator containing unreacted hydrocarbon and CO to enter into a consecutively placed steam reformer to react with steam over a bed of metallic catalyst via the steam reforming and water gas shift reactions and be converted into H₂ and CO₂ products, having this exit stream from last reformer to condense its unreacted steam by passage through a heat exchanger and by generating new steam in other side of the heat exchanger which is used as feed in the inlet of this last reformer, having the final exit dry mixture of H₂ and CO₂ from the heat exchanger to be combined with the permeate from the membrane permeator, H₂ and CO₂ stream, to make one combined stream of H₂ and CO₂ to be used for

chemical synthesis,

also as fuel

either as a mixture or as pure H₂ after the CO₂ condensation and removal.

12. The process of claim 10 wherein the membrane in the permeator is made from an organic polymer or composite or copolymer of organic polymers selected from the group of

polyimides,

polycarbonates,

polysulfones,

polybenziimidazoles,

polyphosphazenes,

polyamides,

polystyrenes,

polycaprolactams,

parylenes,

polyvinyl halides,

polyacetates,

polysiloxanes

or from inorganic-metal composites based on pure or mixture of one of the following ceramic oxides:

alumina (Al₂ O₃),

titania (TiO₂),

silica (SiO₂),

zirconia (ZrO₂).

13. The process of claim 10 wherein the hydrocarbon is a single constituent or a mixture of constituents of the following components

methane,

ethane,

propane,

n-butane,

i-butane,

methanol,

ethanol,

natural gas rich in methane,

coal gas rich in methane,

landfill gas rich in methane,

flue gas rich in methane.

14. The process of claim 10 wherein the feed hydrocarbon and CO₂ gases are substituted by

a CH₄ and CO₂ mixture,

acidic natural gas rich in CH₄ and CO₂,

coal gas rich in CH₄ and CO₂,

landfill gas rich in CH₄ and CO₂,

other refinery and flue gas mixtures rich in CH₄ and CO₂.

15. A process that reacts a hydrocarbon with CO₂ over a bed of metallic catalyst in a CO₂ reforming reactor to produce H₂ and CO via the hydrocarbon CO₂ reforming reaction and the reverse water gas shift reaction, with the exit stream to be passed through a heat exchanger to reduce its temperature and condense any produced steam by generating new steam in other side of the exchanger, which steam can be used as feed into subsequently placed steam reformers, with the exit dry and cooled stream from the heat exchanger to enter into a membrane permeator made by one of the following materials,

organic polymer membrane,

organic polymer membrane-inorganic support,

inorganic membrane,

which all materials are permselective to H₂ and CO₂ and separate these two species through the permeate stream from the unreacted hydrocarbon and product CO which exit from the non-permeate side of the permeator as a reject stream, with the H₂ and CO₂ permeate product mixture to be used for

chemical synthesis,

also as fuel

either as a mixture or as pure H₂ after the CO₂ condensation and removal.

16. The process of claim 15 with the reject stream from the permeator containing unreacted hydrocarbon and CO to enter into a consecutively placed steam reformer to react with steam over a bed of metallic catalyst via the steam reforming and water gas shift reactions and be converted into H₂ and CO₂ product, having this exit stream from last reformer to condense its unreacted steam by passage through a heat exchanger and by generating new steam in the other side of the heat exchanger to be used as feed in the inlet of the last reformer, having the final exit dry mixture of H₂ and CO₂ from the heat exchanger to be combined with the permeate from the membrane permeator, H₂ and CO₂ stream, to make one combined stream of H₂ and CO₂ to be used for

chemical synthesis,

also as fuel

either as a mixture or as pure H₂ after the CO₂ condensation and removal.

17. The process of claim 15 wherein the membrane in the permeator is made from an organic polymer or composite or copolymer of organic polymers selected from the group of

polyimides,

polycarbonates,

polysulfones,

polybenziimidazoles,

polyphosphazenes,

polyamides,

polystyrenes,

polycaprolactams,

parylenes,

polyvinyl halides,

polyacetates,

polysiloxanes

or other organic polymer, composite, copolymer with glass transition temperature above 50°

C., also from inorganic materials and inorganic-metal composites based on pure or mixture of one of the following ceramic oxides;

alumina (Al₂ O₃),

titania (TiO₂),

silica (SiO₂),

zirconia (ZrO₂).

18. The process of claim 15 wherein the hydrocarbon is a single constituent or a mixture of constituents of the following components

methane,

ethane,

propane,

n-butane,

i-butane,

methanol,

ethanol,

natural gas rich in methane,

coal gas rich in methane,

landfill gas rich in methane,

flue gas rich in methane.

19. The process of claim 15 wherein the feed hydrocarbon and CO₂ gases are substituted by

a CH₄ and CO₂ mixture,

acidic natural gas rich in CH₄ and CO₂,

coal gas rich in CH₄ and CO₂,

landfill gas rich in CH₄ and CO₂,

other refinery and flue gas mixtures rich in CH₄ and CO₂.

20. The process of claim 16 wherein the combined H₂ and CO₂ product mixture is used

(a) for direct methanol synthesis via the reaction:

CO₂ +3H₂ ═

CH₃ OH(g)+H₂ O(g),

(b) for direct feed in molten carbonate fuel cell (MCFC) units for electricity generation via the overall electrochemical reaction;

H₂ +CO₂ +1/2O₂ (cathode)→

H₂ O+CO₂ (anode),

(c) for other CO₂ and H₂ or H₂ only chemical synthesis reactions moreover after the removal of CO₂ pure H₂ is used

(d) as fuel in anode of fuel cells such as phosphoric acid, alkaline, molten carbonate, solid oxide, proton exchange,

(e) and as fuel in gas turbines, conventional and jet type gas engines.