PTAB

IPR2025-00281

Berkshire Hathaway Energy Co v. MES Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Mercury Removal From Gas Streams
  • Brief Description: The ’517 patent relates to methods for reducing or separating mercury from mercury-containing gas, such as flue gas from coal combustion. The methods involve adding a bromine-containing additive to the coal or combustion chamber and subsequently collecting the mercury with a sorbent comprising activated carbon.

3. Grounds for Unpatentability

Ground 1: Obviousness over Sjostrom and Eckberg - Claims 1, 4-15, and 17-30 are obvious over Sjostrom in view of Eckberg under 35 U.S.C. §103.

  • Prior Art Relied Upon: Sjostrom (a January 2005 conference presentation) and Eckberg (a January 2005 conference presentation).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sjostrom taught the core elements of the claimed invention, including combusting coal and adding a bromine-containing substance ("Br") at multiple locations—including to the pulverized coal (Location 1) or directly into the combustion chamber (Location 2)—while also injecting an activated carbon sorbent downstream to collect mercury. Eckberg allegedly supplied the implementation details missing from Sjostrom by teaching the specific "chemical injection" of an aqueous calcium bromide (CaBr2) solution into a coal-fired boiler to enhance mercury removal.
    • Motivation to Combine: A POSITA would combine these references to implement the general halogen-addition strategy of Sjostrom using the specific, readily available, and inexpensive bromide compound (CaBr2) disclosed in Eckberg. Further motivation existed because both references were presented consecutively in the same "Mercury-Control" session at the 2005 EUEC conference, addressed the same problem, and shared a common author, suggesting their teachings were complementary and interoperable.
    • Expectation of Success: A POSITA would expect success because the combination amounted to a simple substitution of a specific known element (Eckberg’s CaBr2) for a general one (Sjostrom’s "Br") in a well-understood process to achieve the predictable result of enhanced mercury removal.

Ground 2: Obviousness over Sjostrom and Olson-646 - Claims 1-15 and 17-30 are obvious over Sjostrom in view of Olson-646 under §103.

  • Prior Art Relied Upon: Sjostrom (a January 2005 conference presentation) and Olson-646 (Application # 2006/0048646).
  • Core Argument for this Ground:
    • Prior Art Mapping: As in Ground 1, Sjostrom provided the foundational method of adding bromine to coal/the combustion chamber and using a downstream activated carbon sorbent. Petitioner asserted that Olson-646 provided complementary technical details by teaching that the "halogen/halide promoter" should be in a "gaseous or vapor form" comprising "gaseous HBr or Br2." Olson-646 also described the chemical reaction mechanisms for mercury capture on activated carbon and disclosed collecting greater than 70 wt% of mercury.
    • Motivation to Combine: A POSITA would combine the references to implement Sjostrom's system with the specific chemical promoters (HBr or Br2) and reaction details taught by Olson-646. Olson-646 explained the chemical theory behind the process shown in Sjostrom, motivating a POSITA to use its teachings to optimize the known process. Both references used the same commercial activated carbon (Norit Darco FGD), further suggesting their compatibility.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because the combination involved applying the detailed chemical teachings of Olson-646 to improve the known, practical system of Sjostrom, yielding the predictable result of effective mercury removal.

Ground 3: Anticipation by Olson-235 - Claims 29 and 30 are anticipated by Olson-235 under 35 U.S.C. §102.

  • Prior Art Relied Upon: Olson-235 (Patent 8,652,235).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Olson-235 disclosed every limitation of independent claims 29 and 30. For claim 29, Olson-235 allegedly disclosed a method of separating mercury from a gas by combusting coal, collecting mercury with an activated carbon sorbent, and, critically, introducing a "halogen or halide promoter" (e.g., gaseous HBr or Br2) into the combustion chamber. While Olson-235 did not teach adding the promoter to the coal upstream, its disclosure of direct injection into the combustion chamber met one of the alternatives in the Markush group of claim 29(b), thereby anticipating the claim. The limitations of claim 30 were allegedly disclosed for the same reasons.

4. Key Technical Contentions (Beyond Claim Construction)

  • ’517 Patent Is Not Entitled to Pre-2018 Priority Date: A central contention of the petition was that the ’517 patent was not entitled to a priority date earlier than April 12, 2018. Petitioner argued that claim limitations central to the invention (e.g., "the coal comprising an additive comprising Br2, HBr, a bromide compound...") were "Newly-Introduced Limitations" that lacked written description support in any of the parent applications filed before the ’970 application in 2018. Because this breaks the priority chain, Petitioner asserted that Sjostrom (2005), Eckberg (2005), Olson-646 (2006), and Olson-235 (2014) all qualified as prior art.

5. Arguments Regarding Discretionary Denial

  • §314(a) Denial (Fintiv) Inappropriate: Petitioner argued that discretionary denial would be inappropriate because the parallel district court litigation was in its earliest stages. No answers had been filed, no scheduling orders were in place, and discovery had not commenced, ensuring that an inter partes review (IPR) would be a more efficient resolution.
  • §325(d) Denial Inappropriate: Petitioner argued against denial under §325(d), asserting that the primary prior art references relied upon in the petition (Sjostrom and Eckberg) were never considered by the Examiner during the original prosecution of the ’517 patent or its parent applications.

6. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-15 and 17-30 of Patent 10,596,517 as unpatentable.