Berkshire Hathaway Energy Co v. MES Inc

1. Case Identification

• Case #: IPR2025-00278
• Patent #: 10,343,114
• Filed: January 17, 2025
• Petitioner(s): Berkshire Hathaway Energy Company, Interstate Power & Light Company, MidAmerican Energy Company, PacifiCorp, WEC Energy Group, Inc., and Wisconsin Power & Light Company
• Patent Owner(s): Birchtech Corp.
• Challenged Claims: 1-30

2. Patent Overview

• Title: Sorbents for the Oxidation and Removal of Mercury
• Brief Description: The ’114 patent discloses methods for separating mercury from a mercury-containing gas, such as flue gas from coal combustion. The method involves adding a bromine-containing species to the coal upstream of or into the combustion chamber, and separately injecting an activated carbon sorbent downstream to capture the mercury.

3. Grounds for Unpatentability

Ground 1: Obviousness over Sjostrom in view of Eckberg - Claims 1-9 and 12-30 are obvious over Sjostrom in view of Eckberg.

• Prior Art Relied Upon: Sjostrom (a 2005 conference presentation) and Eckberg (a 2005 conference presentation).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Sjostrom disclosed the core elements of the challenged claims, including a method for mercury removal from flue gas by adding a halogen ("Br") to coal or a combustion chamber (boiler) and injecting an activated carbon sorbent downstream. Sjostrom further taught using particulate separators (ESP or FF), monitoring mercury levels with a continuous emissions monitor (CEM), and controlling the sorbent injection rate to achieve desired removal efficiencies, including over 90%. Petitioner asserted that Eckberg provided the specific implementation details for the halogen injection that Sjostrom referenced generally. Eckberg taught injecting an aqueous solution of calcium bromide (CaBr2) into a coal-fired boiler, which upon combustion forms HBr in the flue gas.
  • Motivation to Combine: A POSITA would combine these references because Eckberg provided specific, readily available, and inexpensive chemical options (CaBr2) to implement the general halogen-addition step taught by Sjostrom. Petitioner highlighted that both references were presented consecutively in the same session at the 2005 Electric Utilities Environment Conference (EUEC), shared a common author, and addressed the identical problem of enhancing mercury removal, making their teachings naturally interoperable.
  • Expectation of Success: A POSITA would have a high expectation of success, as the combination involved a simple substitution of a specific, known halogen compound (Eckberg's CaBr2) for the generic "Br" in Sjostrom's established system to achieve the predictable result of high-efficiency mercury removal.

Ground 2: Obviousness over Sjostrom in view of Olson-646 - Claims 1-30 are obvious over Sjostrom in view of Olson-646.

• Prior Art Relied Upon: Sjostrom (a 2005 conference presentation) and Olson-646 (Application # 2006/0048646).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner again used Sjostrom as the primary reference disclosing the overall process. The combination with Olson-646 was argued to render all claims obvious. Olson-646 taught the underlying chemical mechanism, explaining that a promoter like gaseous HBr or Br2 reacts with activated carbon to form a "promoted sorbent" that is highly effective at capturing mercury. Olson-646 also disclosed key claim limitations nearly verbatim, including controlling the sorbent injection rate in response to a continuous emissions monitor to maintain mercury levels within desired limits, using specific bromine-to-sorbent ratios, and co-injecting secondary materials.
  • Motivation to Combine: A POSITA reviewing Sjostrom's system would look to a reference like Olson-646 to understand the chemical reactions and to identify effective gas-phase promoters (HBr or Br2). Olson-646 provided the scientific explanation and specific compounds that complemented Sjostrom's full-scale process diagram, motivating a POSITA to use HBr or Br2 to optimize the halogen injection step.
  • Expectation of Success: Success would be expected because the combination involved applying the known promoters (HBr/Br2) and control logic from Olson-646 to the established mercury removal framework of Sjostrom. Both references used the same commercial activated carbon (Norit Darco FGD), further ensuring predictable results.

Ground 3: Anticipation by Olson-235 - Claims 1-5, 7-12, 14-18, 20, 23-25, and 27-30 are anticipated by Olson-235.

• Prior Art Relied Upon: Olson-235 (Patent 8,652,235).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the ’114 patent is not entitled to a priority date earlier than its May 2018 filing date, making the 2014-issued Olson-235 patent prior art. Petitioner contended Olson-235 disclosed every element of the challenged claims. For claim 1, Olson-235 was alleged to disclose one alternative of the Markush group for halogen addition—introducing gaseous HBr or Br2 "into a combustion chamber"—which is sufficient for anticipation. Olson-235 was also asserted to expressly teach injecting activated carbon downstream, separating the resulting mercury-sorbent composition, monitoring the cleaned gas, and controlling the sorbent injection rate based on feedback from the monitor to maintain a desired mercury level. The petition mapped limitations of dependent claims to corresponding verbatim or near-verbatim disclosures in Olson-235.

4. Key Technical Contentions (Beyond Claim Construction)

• Priority Date Challenge: A central contention of the petition was that the ’114 patent is not entitled to claim priority to any application filed before May 14, 2018. Petitioner argued that key limitations—specifically, adding certain bromine species (Br2, Br-) or adding any bromine-containing compound "to the coal" upstream of the combustion chamber—were "Newly-Introduced Limitations" that lack written description support in the entire priority chain dating back to 2004. The earlier applications were alleged to only describe pre-brominating a sorbent outside the flue gas stream and then injecting it, which is a different process. This contention was foundational to establishing that Sjostrom, Eckberg, Olson-646, and Olson-235 qualify as prior art.

5. Arguments Regarding Discretionary Denial

• No Denial under §314(a) (Fintiv): Petitioner argued that discretionary denial would be improper because the parallel district court proceedings had just begun. No answers had been filed, substantive discovery had not commenced, and no trial dates were set. A Final Written Decision in the IPR would likely conclude well before any potential trial.
• No Denial under §325(d): Petitioner asserted denial would be inappropriate because the primary references for the obviousness grounds, Sjostrom and Eckberg, were never considered by the Examiner during prosecution. While other references were of record, they were not applied in a substantive rejection, and the Examiner never made findings on the critical priority date issue.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-30 of the ’114 patent as unpatentable.