Berkshire Hathaway Energy Co v. MES Inc

Prosecution History analysis

Examiner Search analysis

Invalidity Framework analysis

Petition

Petition Analysis

## 1. Case Identification
- Case Number: [IPR2025-00422](https://ai-lab.exparte.com/case/ptab/IPR2025-00422)
- Patent #: [10,668,430](https://ai-lab.exparte.com/patent/10668430)
- Filed: February 11, 2025
- Petitioner(s): [Berkshire Hathaway Energy Co](https://ai-lab.exparte.com/party/berkshire-hathaway-energy-co), [Interstate Power and Light Co](https://ai-lab.exparte.com/party/interstate-power-and-light-co), [MidAmerican Energy Co](https://ai-lab.exparte.com/party/midamerican-energy-co), [PacifiCorp](https://ai-lab.exparte.com/party/pacificorp), [WEC Energy Group, Inc](https://ai-lab.exparte.com/party/wec-energy-group-inc), and [Wisconsin Power and Light Co](https://ai-lab.exparte.com/party/wisconsin-power-and-light-co)
- Patent Owner(s): Birchtech Corp.
- Challenged Claims: 1-4 and 6-29

## 2. Patent Overview
- Title: Method of Separating Mercury from a Mercury-Containing Gas
- Brief Description: The [’430 Patent](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1001) relates to a system for removing mercury from flue gas generated by coal combustion. The method involves adding a bromine-containing additive to the coal or combustion chamber to oxidize mercury, followed by injecting an activated carbon sorbent downstream to adsorb the mercury for subsequent separation.

## 3. Grounds for Unpatentability
#### Ground 1: Obviousness over Vosteen589 and Starns - Claims 1-4 and 6-29 are obvious over Vosteen589 in view of Starns.
- **Prior Art Relied Upon:** Application # 2004/0013589 ("[Vosteen589](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1005)"), and Travis [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008), "Full-Scale Test of Mercury Control..." ("[Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008)," June 2002).
- **Core Argument for this Ground:**
    - **Prior Art Mapping:** Petitioner argued that [Vosteen589](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1005) taught the core method of adding bromine or bromide compounds to coal or a furnace to enhance mercury oxidation, followed by removal using a downstream sorbent like activated carbon. However, [Vosteen589](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1005) lacked specific engineering details. [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008), a publicly available conference paper, supplied these details by teaching a mature, practical activated carbon injection (ACI) system, including the use of a bulk-storage silo, blower/feeder trains, injection upstream of an electrostatic precipitator (ESP), and control via a programmable logic controller (PLC).
    - **Motivation to Combine:** A person of ordinary skill in the art (POSITA) would combine the references to implement [Vosteen589](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1005)'s chemical process using the well-established and practical ACI hardware and control methods described in [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008). The combination represented a straightforward pairing of a known chemical treatment with a known engineering solution to achieve the common goal of mercury removal.
    - **Expectation of Success:** A POSITA would have a high expectation of success, as the combination involved using known technologies (halogen addition and ACI) for their intended purposes, which would predictably result in effective mercury capture.

#### Ground 2: Anticipation by Downs-Boiler - Claims 1-4, 6-9, 14-16, 18-19, and 22-28 are anticipated by Downs-Boiler under 35 U.S.C. §102.
- **Prior Art Relied Upon:** Application # 2008/0107579 ("[Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006)").
- **Core Argument for this Ground:**
    - **Prior Art Mapping:** Petitioner asserted that [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006), which claims priority to a 2004 provisional application, disclosed every element of the challenged claims. [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) taught a method for removing mercury from coal combustion flue gas by adding a bromine-containing reagent (e.g., calcium bromide) to the coal before combustion or directly into the combustion chamber. It also explicitly taught injecting a powdered activated carbon (PAC) sorbent downstream to contact the mercury, and subsequently separating the mercury-laden sorbent using a particulate collector like an ESP or fabric filter. [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) also disclosed use with subbituminous and lignite coals and achieving over 70% mercury removal.

#### Ground 3: Obviousness over Downs-Boiler and Starns - Claims 1-4 and 6-29 are obvious over Downs-Boiler in view of Starns.
- **Prior Art Relied Upon:** [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) (’579 application), [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008).
- **Core Argument for this Ground:**
    - **Prior Art Mapping:** As an alternative to anticipation, Petitioner argued that [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) taught the fundamental combination of adding bromine to the fuel/furnace and using downstream PAC injection. [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008) rendered this combination obvious by providing further enabling details. For example, [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008) disclosed specific operational parameters, control strategies for modifying sorbent injection rates based on monitored mercury levels, and the use of specific benchmark sorbents (e.g., Norit Darco FGD), which would have been obvious modifications to optimize the system taught by [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006).
    - **Motivation to Combine:** A POSITA implementing the general method of [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) would naturally look to contemporaneous, practical reports like [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008) for specific, field-tested details on ACI hardware, control processes, and sorbent selection to ensure efficient and cost-effective operation.
    - **Expectation of Success:** Integrating the specific, mature ACI techniques from [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008) into the similar system of [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) was a simple application of a known improvement to achieve the predictable result of enhanced mercury control.

- **Additional Grounds:** Petitioner asserted additional obviousness challenges based on [Vosteen589](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1005) in view of [Mass-EPA](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1009) and [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) in view of [Mass-EPA](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1009). These grounds relied on similar arguments, with a Massachusetts Department of Environmental Protection report ("[Mass-EPA](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1009)," Dec. 2002) providing further evidence of ACI as a mature, well-understood, and cost-effective technology for mercury control.

## 4. Key Technical Contentions (Beyond Claim Construction)
- **Workable Range Optimization:** Petitioner argued that the ratio recited in claim 13 (about 1 g to 30 g of bromine per 100 g of sorbent) was not an inventive feature but an obvious, result-effective variable. The petition contended that a POSITA could readily calculate this ratio by combining the known bromine concentrations taught in [Vosteen589](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1005) or [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006) with the routine sorbent injection rates described in [Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008) or [Mass-EPA](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1009). This routine calculation, using fundamental chemistry principles, would yield a value squarely within the claimed range without achieving any unexpected results.

## 5. Arguments Regarding Discretionary Denial
- Petitioner argued the Board should not deny institution under §314(a) or §325(d). For §314(a) (Fintiv), the petition asserted that the parallel district court litigation had barely begun, with no trial date set, making an inter partes review (IPR) a more efficient resolution. For §325(d), Petitioner contended that the examiner did not cite or consider the key secondary references ([Starns](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1008), [Mass-EPA](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1009)) and failed to appreciate the full scope of the primary references ([Vosteen589](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1005), [Downs-Boiler](https://ai-lab.exparte.com/case/ptab/IPR2025-00422/doc/1006)) during prosecution, which constituted a material error justifying review.

## 6. Relief Requested
- Petitioner requests institution of IPR and cancellation of claims 1-4 and 6-29 of Patent [10,668,430](https://ai-lab.exparte.com/patent/10668430) as unpatentable.

Berkshire Hathaway targets mercury removal patent: 28 claims face anticipation & obviousness challenges from prior art on bromine & carbon injection.