# US 2013/0156502 A1 · Hydrogen storage method and system

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- Number: US 2013/0156502 A1
- Document ID: US20130156502A1
- Status: Published application
- Kind: A1
- Application number: 13/751,531
- Filed: 2013-01-28
- Published: 2013-06-20
- Earliest claimed: 2010-06-10
- Assignees: Praxair Technology, Inc.
- Inventors: Raymond Francis Drnevich
- Web page: https://patentgrep.com/patent/US20130156502A1

## CPC

- B65G 5/00: Storing fluids in natural or artificial cavities or chambers in the earth
- B01D 53/261: {by adsorption}
- B01D 53/263: {by absorption}
- C01B 3/00: Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen; Reversible storage of hydrogen (production of water-gas or synthesis gas from solid carbonaceous material C10J)
- C01B 3/34: by reaction of hydrocarbons with gasifying agents
- C01B 3/48: followed by reaction of water vapour with carbon monoxide
- F17C 1/007: {Underground or underwater storage}
- C01B 2203/0233: the reforming step being a steam reforming step
- C01B 2203/0283: containing a CO-shift step, i.e. a water gas shift step
- C01B 2203/0288: containing two CO-shift steps
- C01B 2203/0294: containing three or more CO-shift steps
- C01B 2203/043: Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
- F17C 2221/012: Hydrogen
- F17C 2221/013: Carbon dioxide
- F17C 2223/0123: gaseous, e.g. CNG, GNC
- F17C 2223/036: Very high pressure (>80 bar)
- F17C 2265/068: Distribution pipeline networks
- F17C 2270/0152: Salt caverns
- Y02C 20/40: of CO2
- Y02E 60/32: Hydrogen storage
- B65G: TRANSPORT OR STORAGE DEVICES, e.g. CONVEYORS FOR LOADING OR TIPPING, SHOP CONVEYOR SYSTEMS OR PNEUMATIC TUBE CONVEYORS (packaging B65B; handling thin or filamentary materials, e.g. paper sheets or thread, B65H; cranes B66C; portable mobile or lifting or hauling appliances, e.g. hoists, B66D; devices for lifting or lowering goods for loading or unloading purposes, e.g. fork-lift trucks, B66F9/00; emptying bottles, jars, casks, barrels or similar containers, not otherwise provided for, B67C9/00; delivering or transferring liquids B67D; filling or discharging vessels for liquefied, solidified or compressed gases F17C; pipe-line systems for fluids F17D)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- F17C: VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00; construction or assembling of bulk storage containers employing civil-engineering techniques E04H7/00; variable-capacity gas-holders F17B; liquefaction or refrigeration machines, plants, or systems F25)
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method and system for storing and supplying hydrogen to a hydrogen pipeline in which a compressed hydrogen feed stream is introduced into a salt cavern for storage and a stored hydrogen stream is retrieved from the salt cavern and reintroduced into the hydrogen pipeline. A minimum quantity of stored hydrogen is maintained in the salt cavern to produce a stagnant layer having a carbon dioxide content along the cavern wall and the top of a residual brine layer located within the salt cavern. The compressed hydrogen feed stream is introduced into the salt cavern and the stored hydrogen stream is withdrawn without disturbing the stagnant layer to prevent carbon dioxide contamination from being drawn into the stored hydrogen stream being reintroduced into the hydrogen pipeline. This allows the stored hydrogen stream to be reintroduced into the hydrogen pipeline without carbon dioxide removal.

## Claims

### Claim 1

A system for storing and supplying hydrogen to a hydrogen pipeline comprising:
a compressor for compressing a feed stream of the hydrogen to produce a compressed hydrogen feed stream;
a salt cavern having a residual brine layer located at a bottom region of the salt cavern and side regions extending upwardly from the bottom region of the salt cavern;
at least one conduit in communication with the salt cavern for injecting the compressed hydrogen feed stream into a salt cavern to produce stored hydrogen within the salt cavern and for withdrawing a stored hydrogen stream composed of stored hydrogen from the salt cavern, the at least one conduit having at least one lower end located in an interior region of the salt cavern and spaced above the brine layer and from the side regions of the salt cavern;
a flow network configured to selectively connect the compressor to the at least one conduit such that the compressed hydrogen feed stream is injected into the salt cavern to produce the stored hydrogen within the salt cavern and to selectively connect the at least one conduit to the hydrogen pipeline such that the stored hydrogen stream is injected into the pipeline without removing carbon dioxide contained in the stored hydrogen stream;
that salt cavern having at least a minimum quantity of the stored hydrogen within the salt cavern before, during, and between times at which the compressed hydrogen feed stream is injected and at which the stored hydrogen stream is withdrawn such that a stagnant layer of hydrogen is maintained that has at least a bottom portion overlying the residual brine layer and a lateral portion situated along side regions of the salt cavern, the stagnant layer having a carbon dioxide content that is a potential source of carbon dioxide contamination to the stored hydrogen stream; and
means for limiting the flow rates and the velocities at which the compressed hydrogen feed stream is injected into the salt cavern and the stored hydrogen stream is withdrawn from the salt cavern such that the stagnant layer is not disturbed and the carbon dioxide contamination of the stored hydrogen stream from the stagnant layer is inhibited, the minimum volume of the hydrogen stored within the salt cavern is maintained at a volume ratio equal to a stored volume of the hydrogen to the actual cavern volume of no less than 29.0 scf/cf;
the at least one lower end of the at least one conduit is open;
the at least one lower end of the at least one conduit is spaced from the residual brine layer at a lower vertical distance of no less than 250 feet;
the at least one lower end of the at least one conduit is spaced from the side regions of the salt cavern at a lateral distance of no less than 40 feet from a vertical line extending between 10 and 250 feet below the at least one lower end of the at least one conduit; and
the flow rates and velocities are limited such that, as measured at the at least one lower end of the at least one conduit, the compressed hydrogen feed stream is injected at an injection ratio equal to an injection flow rate of the compressed hydrogen feed stream to the actual cavern volume of no greater than 7.5 scfd/cf and at an injection velocity of the compressed hydrogen feed stream of no greater than 100 feet per second and the stored hydrogen stream is withdrawn at a withdrawal ratio equal to the withdrawal flow rate of the stored hydrogen stream to the actual cavern volume of no greater than 10.0 scfd/cf and at a withdrawal velocity of the stored hydrogen stream of no greater than 150 feet per second.

### Claim 2 (depends on 1)

The system of claim 1, wherein:
the at least one lower end of the at least one conduit is spaced below a top region of the salt cavern, located opposite to the bottom region of the salt cavern; and
the stagnant layer also has a top portion extending along the top region of the salt cavern and situated opposite to the bottom portion of the stagnant layer.

### Claim 3 (depends on 1)

The system of claim 1, wherein the flow network has a drying unit positioned within the flow network to remove water from the stored hydrogen stream prior to injection into the pipeline.

### Claim 4 (depends on 1)

The system of claim 1, wherein:
the compressor compresses the hydrogen feed stream such that the compressed hydrogen feed stream is injected into the salt cavern at a cavern pressure that is above the pipeline pressure; and
the flow network is configured to reduce the cavern pressure of the stored hydrogen stream to the pipeline pressure prior to injecting the stored hydrogen stream into the pipeline.

### Claim 5 (depends on 4)

The system of claim 4, wherein the at least one conduit is an injection conduit from which the compressed hydrogen feed stream is injected into the salt cavern and a withdrawal conduit from which the stored hydrogen stream is withdrawn from the salt cavern through a withdrawal conduit.

### Claim 6 (depends on 1)

The system of claim 1, wherein the at least one conduit comprises an injection conduit having a flow diffuser from which at least the compressed hydrogen feed stream is injected into the salt cavern.

### Claim 7 (depends on 1)

The system of claim 1, wherein:
the at least one lower end of the at least one conduit is spaced below a top region of the salt cavern, located opposite to the bottom region of the salt cavern;
the stagnant layer also has a top portion extending along the top region of the salt cavern and situated opposite to the bottom portion of the stagnant layer; and
the at least one lower end of the at least one conduit is spaced from the top region of the salt cavern at an upper vertical distance of no less than 50 feet.