Berkshire Hathaway Energy Co v. MES Inc

1. Case Identification

• Case #: IPR2025-00423
• Patent #: 10,668,430
• Filed: February 11, 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: 1-4 and 6-29

2. Patent Overview

• Title: Method of Separating Mercury from a Gas
• Brief Description: The ’430 patent relates to methods for removing mercury from flue gas generated by coal combustion. The claimed method involves adding a bromine-containing additive to coal before it enters the combustion chamber or directly into the chamber, and subsequently injecting an activated carbon sorbent downstream to capture the mercury.

3. Grounds for Unpatentability

Ground 1: Obviousness over Sjostrom and Eckberg - Claims 1-4, 6-29

• 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 claimed method. Sjostrom taught a system for enhancing mercury removal by adding halogens, including bromine ("Br"), at three potential locations: to the pulverized coal before the boiler (Location 1), directly into the combustion chamber (Location 2), or to the sorbent downstream (Location 3). Sjostrom also explicitly taught injecting an activated carbon sorbent downstream of the combustion chamber to capture mercury from the flue gas and separating the resulting sorbent using particulate control devices like an electrostatic precipitator (ESP).
  • Motivation to Combine: Petitioner contended a person of ordinary skill in the art (POSITA) would combine Sjostrom with Eckberg to implement Sjostrom’s high-level framework. While Sjostrom taught adding "Br," it lacked specific details on the chemical form or quantity. Eckberg, presented at the same conference session, provided these exact implementation details. Eckberg described injecting an aqueous solution of a specific bromide compound (calcium bromide, CaBr₂) into a coal-fired boiler to enhance mercury removal. A POSITA would have been motivated to use the specific, readily available, and effective bromide compound from Eckberg to practice the general method taught by Sjostrom to achieve predictable improvements in mercury capture.
  • Expectation of Success: A POSITA would have had a high expectation of success because both references addressed the same problem using the same fundamental technique (bromine addition for mercury control in coal plants) and were presented as related, interoperable technologies.

Ground 2: Obviousness over Sjostrom and Olson-646 - Claims 1-4, 6-29

• Prior Art Relied Upon: Sjostrom and Olson-646 (Application # 2006/0048646).
• Core Argument for this Ground:
  • Prior Art Mapping: As in Ground 1, Petitioner relied on Sjostrom to teach the overall process of adding bromine to coal or the combustion chamber and injecting an activated carbon sorbent downstream. The combination with Olson-646 was argued to render obvious specific chemical species and reaction mechanisms.
  • Motivation to Combine: A POSITA would have looked to Olson-646 to provide the scientific rationale and chemical details for Sjostrom’s system. Olson-646 taught that the active halogen promoter is in a gaseous or vapor form, specifically "gaseous HBr or Br₂." A POSITA would understand that adding a bromide compound to the coal or combustion chamber, as taught by Sjostrom, would produce these exact gaseous promoters at combustion temperatures. Olson-646 also disclosed workable ratios of promoter-to-sorbent (1-30g per 100g) and confirmed the combination could achieve greater than 70% mercury removal. The motivation was to apply the chemical principles of Olson-646 to optimize the system in Sjostrom.
  • Expectation of Success: The combination involved using a known promoter (bromine compounds taught by Olson-646) to improve a known process (mercury capture with activated carbon as in Sjostrom), leading to the predictable result of enhanced mercury removal.

Ground 3: Anticipation by Olson-235 - Claims 1, 3, 6-7, 10-29

• Prior Art Relied Upon: Olson-235 (Patent 8,652,235).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that because the ’430 patent is not entitled to a priority date before April 2018, the 2014-issued Olson-235 patent anticipated the challenged claims. Petitioner argued Olson-235 disclosed every limitation of the independent claims. Olson-235 taught a method where a halogen/halide promoter (e.g., "gaseous HBr or Br₂") is introduced into a combustion chamber where coal is burned. It further disclosed injecting a powdered activated carbon sorbent downstream of the chamber to contact and capture mercury, followed by separating the sorbent from the cleaned flue gas. Olson-235 also expressly disclosed using a continuous emissions monitor to measure mercury and provide feedback to control the sorbent injection rate, meeting the limitations of claims 10-12.

4. Key Technical Contentions (Beyond Claim Construction)

• Priority Date Challenge: A central contention of the petition was that the ’430 patent is not entitled to claim priority to its provisional application (filed in 2004) or any application filed before April 12, 2018. Petitioner argued that the specific claim limitations requiring the addition of "Br₂, HBr, a bromide compound, or a combination thereof" to the coal or combustion chamber were "Newly-Introduced Limitations" that lack written description support in the pre-2018 applications. As this new matter allegedly broke the priority chain, the asserted prior art from 2005, 2006, and 2014 was argued to be effective against the challenged claims.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not discretionarily deny institution. Under 35 U.S.C. §314(a), it was asserted that the parallel district court litigation was in its nascent stages, with no trial date set and minimal discovery having occurred. Under 35 U.S.C. §325(d), Petitioner argued that the Examiner did not consider Sjostrom or Eckberg during prosecution and did not substantively reject claims over Olson-235 or Olson-646. Petitioner also noted that the Board had previously instituted IPRs on related patents using the same prior art.

6. Relief Requested

• Petitioner requested that the inter partes review of the ’430 patent be instituted and that challenged claims 1-4 and 6-29 be cancelled as unpatentable.