PTAB

IPR2015-01073

Air Liquide Large Industries US LP v. Praxair Technology Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method of Storing and Supplying Hydrogen to a Pipeline
  • Brief Description: The ’011 patent discloses a method for managing the supply of gaseous hydrogen to a pipeline network to meet variable demand. The method involves compressing a hydrogen stream, storing it in a subterranean salt cavern, later recovering a crude hydrogen stream from the cavern, purifying it to remove specific impurities like carbon dioxide and water vapor, and supplying the purified hydrogen product to the pipeline.

3. Grounds for Unpatentability

Ground 1: Obviousness over Yanagihara and Pottier - Claims 1-3, 8

  • Prior Art Relied Upon: Yanagihara (Patent 4,444,727) and Pottier (a 1995 article titled “Mass Storage of Hydrogen”).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Yanagihara taught the core process of recovering impure hydrogen gas from a storage container, purifying it by removing water and carbon dioxide to meet a pre-specified purity level for a given "end use," and supplying the purified gas to a pipeline. Pottier was cited for its teaching that storing large quantities of compressed hydrogen in subterranean salt caverns was a well-known technique used for over 20 years for applications like peak-shaving storage. Pottier also explicitly disclosed that hydrogen recovered from such storage contains water vapor and other impurities that would require purification.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine these references by substituting Yanagihara’s generic storage container with Pottier’s well-known salt cavern. The motivation was to apply Yanagihara’s purification and supply method to the large-scale, commercially relevant storage applications described in Pottier, such as energy infrastructure development and peak load balancing. Petitioner asserted this was a simple and obvious substitution of one known element for another to obtain predictable results.
    • Expectation of Success: A POSITA would have a high expectation of success, as combining a known large-scale storage method with a known gas purification process was a straightforward application of established technologies to solve a known problem of matching hydrogen supply with demand.

Ground 2: Obviousness over Yanagihara, Pottier, and Scott - Claims 1-3, 8

  • Prior Art Relied Upon: Yanagihara (Patent 4,444,727), Pottier (1995 article), and Scott (Patent 4,365,978).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination of Yanagihara and Pottier by adding Scott to address the specific impurity of carbon dioxide. While Pottier mentioned "other impurities," Scott was cited for its explicit disclosure that large quantities of carbon dioxide can enter the brine of a solution-mined salt cavern and subsequently off-gas into the stored product, necessitating later purification.
    • Motivation to Combine: A POSITA, knowing from Pottier that impurities were a general concern, would consult a reference like Scott to understand the specific types of contaminants common to salt cavern storage. Scott provided the specific knowledge that carbon dioxide contamination was a known phenomenon, directly reinforcing the reason to include the carbon dioxide removal step taught by Yanagihara when using a salt cavern. This combination directly refuted the ’011 patent’s premise that carbon dioxide contamination from salt caverns was a novel discovery.

Ground 3: Obviousness over Yanagihara, Pottier, and Thomas - Claim 7

  • Prior Art Relied Upon: Yanagihara (Patent 4,444,727), Pottier (1995 article), and Thomas (Patent 4,183,369).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed the specific pressure limitations of claim 7, which required compressing hydrogen to ~2200 psig for storage and reducing it to ~600-800 psig for pipeline distribution. Pottier taught that salt cavern storage pressures could be high (e.g., 850-2600 psi), compatible with the claimed storage pressure. Thomas taught that selecting pipeline pressure is a routine design consideration based on economic and engineering trade-offs, and that pressures in the 600-800 psi range were common for hydrogen pipelines at the time of the invention.
    • Motivation to Combine: A POSITA would be motivated to select operating pressures for the system by consulting known principles for storage and distribution. The teachings of Pottier (on salt cavern pressure tolerance) and Thomas (on conventional pipeline pressures) provided a clear rationale for arriving at the claimed ranges through routine optimization, not invention.

Ground 4: Obviousness over Yanagihara, Pottier, and Funke - Claim 8

  • Prior Art Relied Upon: Yanagihara (Patent 4,444,727), Pottier (1995 article), and Funke (a 2002 technical paper).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed the high-purity specifications of claim 8 (e.g., ~99.99% pure hydrogen). Yanagihara taught generally purifying hydrogen to meet "end uses." Funke was cited for explicitly teaching a hydrogen purification system that removes contaminants like water and CO2 to achieve 99.99% purity for specific high-purity end uses.
    • Motivation to Combine: A POSITA, seeking to supply hydrogen for an end use requiring 99.99% purity, would obviously be motivated to incorporate a known high-purity purification system, such as that described in Funke, into the overall storage and delivery framework established by Yanagihara and Pottier. This was presented as a routine optimization of purity level to meet the known requirements of a particular customer or application.

4. Key Claim Construction Positions

  • Petitioner argued that claim terms should be given their broadest reasonable interpretation consistent with the specification.
  • "Pipeline": Construed broadly to mean "all parts of those physical facilities through which gas moves in transportation," consistent with the definition in federal regulations.
  • "Product Purity Specification": Defined as a pre-determined level of hydrogen purity and a maximum level for specific impurities (like CO2 and water vapor) based on the intended end use of the gas.
  • "Crude Hydrogen Stream": The impure hydrogen gas recovered from storage before it undergoes the claimed purification step.

5. Key Technical Contentions (Beyond Claim Construction)

  • The central technical contention was that the premise of the ’011 patent—that the inventors discovered that storing hydrogen in salt caverns introduces unacceptable levels of carbon dioxide and water vapor—was factually incorrect.
  • Petitioner asserted, based on the teachings of Pottier and Scott, that contamination of stored gas in salt caverns, including by water and CO2, was a well-understood phenomenon in the art long before the invention. The examiner's allowance was allegedly based on this flawed premise.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1, 2, 3, 7, and 8 of the ’011 Patent as unpatentable under 35 U.S.C. §103.