Berkshire Hathaway Energy Co v. MES Inc

1. Case Identification

• Case #: IPR2025-00274
• Patent #: 10343114
• 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: Method of Separating Mercury from a Mercury-Containing Gas
• Brief Description: The ’114 patent relates to methods for removing mercury from flue gas generated by coal combustion. The method involves adding bromine-containing species to the coal or combustion chamber and injecting an activated-carbon sorbent downstream to capture the mercury for later separation.

3. Grounds for Unpatentability

Ground 1: Obviousness over Vosteen589 and Starns - Claims 1-30 are obvious over Vosteen589 in view of Starns.

• Prior Art Relied Upon: Vosteen589 (Application # 2004/0013589) and Starns (a 2002 conference paper).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Vosteen589 taught the core chemical process of the ’114 patent: adding bromine, hydrogen bromide, or bromide compounds to coal upstream of a furnace or directly to the flue gas to improve mercury removal by a downstream activated carbon sorbent. However, Petitioner contended Vosteen589 lacked specific implementation details for the activated carbon injection (ACI) system. Starns allegedly supplied these details, describing ACI as the "most mature, retrofit technology" for mercury control. Starns disclosed the necessary hardware (e.g., bulk-storage silos, blower/feeder trains) and control methods, such as using a programmable logic controller to adjust sorbent injection rates in response to monitored mercury concentration, thereby satisfying the control limitations of claims 1, 24, and 28.
  • Motivation to Combine: A POSITA would combine the teachings to implement Vosteen589's chemical process using the well-known, practical, and mature ACI technology detailed in Starns. This combination would predictably improve mercury removal efficiency and provide the necessary operational control for a commercial power plant.
  • Expectation of Success: Because ACI was a mature, well-understood technology for injecting sorbents to remove pollutants, a POSITA would have had a high expectation of success in applying the hardware and control schemes from Starns to the process taught by Vosteen589.

Ground 2: Anticipation by Downs-Boiler - Claims 23, 25-27, and 30 are anticipated by Downs-Boiler.

• Prior Art Relied Upon: Downs-Boiler (Application # 2008/0107579).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Downs-Boiler disclosed every element of the challenged independent claims. Downs-Boiler taught a method for enhanced mercury removal from coal combustion flue gas by adding a bromine-containing reagent (such as HBr, Br₂, or calcium bromide) to the coal upstream of the combustion chamber or directly into the boiler. It further disclosed injecting a powdered activated carbon (PAC) sorbent into the flue gas downstream of the combustion chamber to contact and adsorb mercury, followed by separating the resulting mercury/sorbent composition in a downstream particulate collector (e.g., an ESP or fabric filter). Petitioner argued this disclosure met all limitations of independent claims 23 and 25, as well as several dependent claims.

Ground 3: Obviousness over Downs-Boiler and Starns - Claims 1-8 and 12-30 are obvious over Downs-Boiler in view of Starns.

• Prior Art Relied Upon: Downs-Boiler (Application # 2008/0107579) and Starns (a 2002 conference paper).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that while Downs-Boiler taught the core combination of bromine addition and downstream PAC injection, it did not explicitly detail a feedback control loop for the injection system. Starns provided the teachings for this missing element, disclosing the continuous monitoring of mercury content in the cleaned gas and controlling the sorbent injection rate in response to maintain mercury levels below a desired threshold. This combination allegedly rendered claims with control limitations (e.g., claim 1) obvious. Starns also provided specifics on sorbent injection rates (e.g., 10 lb/MMacf) that, when combined with bromine concentrations disclosed in Downs-Boiler, would result in the claimed ratios of bromine-to-sorbent recited in claims 4 and 29.
  • Motivation to Combine: A POSITA would be motivated to supplement the process in Downs-Boiler with the detailed control schemes from Starns. This would allow for routine process optimization, ensuring regulatory compliance and minimizing operational costs by avoiding excessive sorbent use, which are standard objectives in the field.
  • Expectation of Success: A POSITA would have reasonably expected success in applying the mature control technology of Starns to the system in Downs-Boiler, as it represented a logical and predictable way to optimize a known mercury removal process.

• Additional Grounds: Petitioner asserted additional obviousness challenges based on Vosteen589 in view of Mass-EPA (a 2002 environmental report) and Downs-Boiler in view of Mass-EPA, which provided similar disclosures to Starns regarding ACI as a mature, well-understood technology with established hardware and control parameters.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not discretionarily deny institution under §314(a) based on Fintiv factors because the parallel district court litigation had only recently begun. At the time of filing, no answers had been filed, discovery had not opened, and no trial dates were set, meaning an FWD would likely issue well before any trial.
• Petitioner also argued against denial under §325(d), contending that the examiner had not previously considered the core secondary references, Starns and Mass-EPA, during prosecution. Petitioner asserted that these references disclose key implementation and control details central to the obviousness arguments, and their absence from prosecution constituted a material oversight.

5. Relief Requested

• Petitioner requested institution of an IPR and cancellation of claims 1-30 of the ’114 patent as unpatentable.