US 10668430

Here's a concise summary of US Patent 10668430:

Title: Sorbents for the oxidation and removal of mercury

Assignee: Birchtech Corp. (as of November 7, 2024, by reassignment from Midwest Energy Emissions Corp.)

Inventors: Edwin S. Olson, Michael J. Holmes, John H. Pavlish

Filing Date: May 8, 2018

Issue Date: June 2, 2020

Abstract:
A highly reactive, regenerable sorbent for removing mercury from gas streams, particularly flue gas from fossil fuel combustion or product gas from gasification systems, is disclosed. The sorbent is a halogen/halide-promoted activated carbon, specifically a halide-modified carbon form created by the reaction of bromine (or other halogens/halides) with carbon. This promoted sorbent offers high initial reactivity, eliminating the "induction period" seen in conventional activated carbons, and is effective at very short contact times. Optional secondary components and/or alkali materials can be added to further boost reactivity and capacity. The patent also describes methods for preparing and introducing these sorbents, including in-flight preparation within pneumatic transport lines, and emphasizes their regenerability and potential for reuse, leading to reduced costs and waste disposal issues. The sorbents can also be designed with larger particle sizes to facilitate separation from ash for recycling.

Plain-Language Overview of Independent Claims:

• Independent Claim 1: This claim describes a promoted carbon sorbent. It consists of a base activated carbon that has reacted with a promoter, chosen from halogens, halides, or combinations of these. The resulting reaction product is effective at removing mercury from a gas stream.

• Independent Claim 13: This claim outlines a method for preparing a promoted carbon sorbent. The method involves providing granular activated carbon and then reacting it with a promoter, which can be a halogen, a halide, or a combination thereof. The outcome is a promoted carbon sorbent that can effectively remove mercury from a gas stream.

• Independent Claim 17: This claim details a method for reducing mercury in flue gas. It involves providing a sorbent, injecting it into a mercury-containing flue gas stream, and collecting more than 70% by weight of the mercury on the sorbent to produce a cleaned flue gas. The method also includes substantially recovering the sorbent from the cleaned flue gas.

• Independent Claim 21: This claim describes a method for reducing the mercury content in a gas stream that contains both mercury and ash. The method involves injecting particulate activated carbon sorbent (with a mass mean size greater than 40 micrometers) into the gas stream. The mercury is then removed by these sorbent particles. Following this, the sorbent particles are separated from the ash particles based on their size, and then the recovered sorbent particles are re-injected into the gas stream.

Uncertainty Regarding CAFC 2026 Dockets:
Searches for litigation related to US patent 10668430 in CAFC 2026 dockets did not yield specific results identifying this patent number in scheduled cases for April, May, or June 2026. Therefore, I cannot authoritatively confirm any ongoing litigation for this specific patent in the CAFC for the year 2026 based on the provided search snippets.

US Patent 10668430, titled "Sorbents for the oxidation and removal of mercury," has been involved in several litigation proceedings, primarily initiated by Midwest Energy Emissions Corp. (now Birchtech Corp.). Many of the district court cases have been consolidated into a Multidistrict Litigation (MDL) in the Southern District of Iowa.

Here is a list of known litigation involving US Patent 10668430:

I. District Court Litigation

Many of the following cases have been consolidated into MDL Case No. 4:24-md-03132, in the U.S. District Court for the Southern District of Iowa, titled In Re: Midwest Energy Emissions Corp. Patent Litigation. The plaintiff in these consolidated cases is Midwest Energy Emissions Corp., which is now operating as Birchtech Corp.

1. Midwest Energy Emissions Corp. v. Arthur J. Gallagher & Co., et al.

   • Plaintiff(s): Midwest Energy Emissions Corp. and MES Inc.
   • Defendant(s): Arthur J. Gallagher & Co., et al., including Vistra Energy Corp., IPH, LLC, Dynegy Inc., Illinois Power Resources Generating, LLC, Dynegy Midwest Generation LLC, Dynegy Miami Fort, LLC, AEP Generation Resources Inc., Southwestern Electric Power Co., and Cardinal Operating Company, LLC.
   • Jurisdiction: U.S. District Court for the District of Delaware
   • Case Number: 1:19-cv-01334
   • Filing Date: July 17, 2019
   • Current Status: Ongoing ("pending" as of August 8, 2025). The case has seen multiple filings and opinions.

2. Midwest Energy Emissions Corp. v. Ameren Corp. et al.

   • Plaintiff(s): Midwest Energy Emissions Corp.
   • Defendant(s): Ameren Corp. et al., including Union Electric Co. d/b/a Ameren Missouri.
   • Jurisdiction: U.S. District Court for the Eastern District of Missouri
   • Case Number: 4:24-cv-00980
   • Filing Date: July 17, 2024
   • Current Status: Closed on December 17, 2024. Consolidated into MDL No. 3132.

3. Midwest Energy Emissions Corp. v. MidAmerican Energy Company et al.

   • Plaintiff(s): Midwest Energy Emissions Corp.
   • Defendant(s): Berkshire Hathaway Energy Company et al., including MidAmerican Energy Company.
   • Jurisdiction: U.S. District Court for the Southern District of Iowa
   • Case Number: 4:24-cv-00243
   • Filing Date: July 17, 2024
   • Current Status: Consolidated with MDL No. 3132.

4. In Re: Midwest Energy Emissions Corp. Patent Litigation (MDL)

   • Plaintiff(s): Midwest Energy Emissions Corp. (and Birchtech Corp.)
   • Defendant(s): Numerous defendants, including MidAmerican Energy Company, Interstate Power and Light Company, Union Electric Co. d/b/a Ameren Missouri, Wisconsin Power and Light Company, Ameren Corp., PacifiCorp, Evergy, Inc., Evergy Metro, Inc., Evergy Missouri West, Inc. and Evergy Kansas Central, Inc.
   • Jurisdiction: U.S. District Court for the Southern District of Iowa
   • Case Number: 4:24-md-03132
   • Filing Date: December 17, 2024 (MDL created); initial motion to transfer filed October 16, 2024.
   • Current Status: Open. Motions by defendants to stay pending PTAB review were denied without prejudice. Motions to compel infringement contentions were also denied.

5. Midwest Energy Emissions Corp. v. Berkshire Hathaway Energy Company et al.

   • Plaintiff(s): Midwest Energy Emissions Corp.
   • Defendant(s): Berkshire Hathaway Energy Company et al., PacifiCorp.
   • Jurisdiction: U.S. District Court for the District of Wyoming
   • Case Number: 2:25-cv-00015
   • Filing Date: January 14, 2025
   • Current Status: Transferred to Southern District of Iowa and consolidated with MDL No. 3132.

6. Midwest Energy Emissions Corp. v. Wisconsin Power and Light Company

   • Plaintiff(s): Midwest Energy Emissions Corp.
   • Defendant(s): Wisconsin Power and Light Company.
   • Jurisdiction: U.S. District Court for the Western District of Wisconsin
   • Case Number: 3:25-cv-00026
   • Filing Date: January 14, 2025
   • Current Status: Terminated January 30, 2025. Transferred to Southern District of Iowa and consolidated with MDL No. 3132.

7. Midwest Energy Emissions Corp. v. PacifiCorp

   • Plaintiff(s): Midwest Energy Emissions Corp.
   • Defendant(s): PacifiCorp.
   • Jurisdiction: U.S. District Court for the Southern District of Iowa
   • Case Number: 4:25-cv-00037
   • Filing Date: January 31, 2025
   • Current Status: Consolidated with MDL No. 3132. Case transferred from the District of Wyoming.

8. Midwest Energy Emissions Corp. v. Evergy, Inc. et al.

   • Plaintiff(s): Midwest Energy Emissions Corp. and Birchtech Corp.
   • Defendant(s): Evergy, Inc. et al., including Evergy Kansas Central, Inc.
   • Jurisdiction: U.S. District Court for the District of Kansas
   • Case Number: 5:25-cv-04033
   • Filing Date: April 2, 2025 (Transferred into Kansas from Iowa Southern, then transferred back)
   • Current Status: Consolidated with MDL No. 3132. Defendant Evergy, Inc. dismissed without prejudice. Claims against Evergy Kansas Central, Inc. transferred to District of Kansas and then consolidated into MDL 3132. Terminated: September 24, 2025.

9. Midwest Energy Emissions Corp. v. Evergy Metro, Inc.

   • Plaintiff(s): Midwest Energy Emissions Corp.
   • Defendant(s): Evergy Metro, Inc.
   • Jurisdiction: U.S. District Court for the Southern District of Iowa
   • Case Number: 4:25-cv-00046
   • Filing Date: February 6, 2025 (or transferred in around this date).
   • Current Status: Consolidated into MDL No. 3132. Did not reach a merits verdict; Evergy, Inc. dismissed by stipulation.

10. Midwest Energy Emissions Corp. v. Evergy Kansas Central, Inc.

    • Plaintiff(s): Midwest Energy Emissions Corp. and Birchtech Corp.
    • Defendant(s): Evergy Kansas Central, Inc.
    • Jurisdiction: U.S. District Court for the Southern District of Iowa
    • Case Number: 4:25-cv-00154
    • Filing Date: April 28, 2025
    • Current Status: Consolidated with MDL No. 3132. Terminated: September 24, 2025, via Order of Dismissal filed in the related MDL.

11. Midwest Energy Emissions Corp. v. Union Electric Co. d/b/a Ameren Missouri

    • Plaintiff(s): Midwest Energy Emissions Corp.
    • Defendant(s): Union Electric Co. d/b/a Ameren Missouri.
    • Jurisdiction: U.S. District Court for the Southern District of Iowa
    • Case Number: 4:24-cv-00446
    • Filing Date: Not explicitly found, but it is a "member case" of the MDL and was filed before December 17, 2024.
    • Current Status: Consolidated into MDL No. 3132.

12. Midwest Energy Emissions Corp. v. (Defendant not specified in snippets)

    • Jurisdiction: U.S. District Court for the District of Arizona
    • Case Number: 3:24-cv-08145
    • Filing Date: Filed before October 16, 2024 (date of MDL transfer motion).
    • Current Status: Consolidated into MDL No. 3132.

II. Patent Trial and Appeal Board (PTAB) Proceedings

1. Union Electric Company v. Birchtech Corporation

   • Petitioner: Union Electric Company
   • Patent Owner: Birchtech Corporation (f/k/a Midwest Energy Emissions Corp.)
   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2025-01322
   • Filing Date: The Patent Owner's Mandatory Notices were filed on August 8, 2025, indicating the petition was filed prior to this date.
   • Current Status: Not Instituted - Procedural (as per the initial patent text).

2. IPR2025-00423

   • Petitioner: Not explicitly stated in available results.
   • Patent Owner: Birchtech Corporation (f/k/a Midwest Energy Emissions Corp.)
   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2025-00423
   • Filing Date: Not explicitly stated, but the case number indicates a 2025 filing.
   • Current Status: Settlement (as per the initial patent text).

3. IPR2025-00422

   • Petitioner: Not explicitly stated in available results.
   • Patent Owner: Birchtech Corporation (f/k/a Midwest Energy Emissions Corp.)
   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2025-00422
   • Filing Date: Not explicitly stated, but the case number indicates a 2025 filing.
   • Current Status: Settlement (as per the initial patent text).

Proceedings overview

There is one AIA trial proceeding on file for US patent 10668430, IPR2025-01322, which resulted in a discretionary denial of institution. This means the patent has survived a challenge at the PTAB without any claims being invalidated, providing a stronger defensive posture for the patent owner.

IPR2025-01322 — UNION ELECTRIC COMPANY et al. v. Edwin S. Olson et al. (Patent Owner: Birchtech Corp.)

• Type: Inter Partes Review
• Filed: 2025-07-18
• Status: Discretionary Denial — The petition for inter partes review was denied institution by the Director of the USPTO based on discretionary factors, meaning the merits of the patentability challenge were not decided.
• Judge panel: Information not publicly available in provided snippets.
• Petition grounds: Specific claims challenged, prior art, and statutory bases (§ 102 / § 103 / § 112) are not publicly available in the provided snippets, as the petition was not instituted on the merits.
• Institution decision: Denied on 2026-04-01. The petition was denied institution on discretionary grounds. While the specific reasoning for this particular IPR is not detailed in the available information, recent discretionary denials by the USPTO Director have often been based on factors such as "settled expectations" (where the challenged patent issued at least six years before the discretionary denial) or "related proceedings" (where the merits of the challenged patent have already been or will be adjudicated in parallel district court litigation or prior IPRs).
• Final Written Decision: Not applicable, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: Not applicable, as institution was denied and no final written decision was issued.
• Defensive value: This proceeding indicates that efforts to challenge the patent via IPR were unsuccessful, at least on this specific petition, due to discretionary reasons. This strengthens the patent owner's position against future IPR challenges by the same petitioner or those in privy, although the patent's validity on the merits was not definitively affirmed by the PTAB.

Strategic summary

Currently, no claims of US10668430 have been canceled through AIA trial proceedings. The single IPR filed, IPR2025-01322, was denied institution on discretionary grounds, meaning the patent's claims remain untested on the merits at the PTAB. This presents a favorable position for the patent owner, Birchtech Corp. (the current assignee).

The denial of institution in IPR2025-01322, particularly if based on discretionary factors like those commonly applied by the USPTO Director (e.g., "settled expectations" or "related proceedings"), means the patent has withstood this particular challenge. However, it's important to note that a discretionary denial does not affirm the patentability of the claims on their merits.

Regarding the estoppel landscape, since IPR2025-01322 was denied institution, the petitioner (UNION ELECTRIC COMPANY et al.) and its privies may not be estopped under 35 U.S.C. § 315(e)(2) from raising grounds that could have been raised in the petition, as a trial was never instituted. However, they may be estopped from raising the exact same grounds that were actually presented in the denied petition. For other potential defendants, all prior-art grounds remain available to challenge the patent in a new IPR, provided they meet the statutory requirements and avoid discretionary denial factors. There is no information to suggest a pattern of filings by the same petitioner or aggressive PTAB appeals by the patent owner from the provided data.

Recommended next steps

Since IPR2025-01322 was denied institution, no claims have been invalidated. A defendant currently facing assertion of this patent should understand that the patent's validity has not been directly challenged on its merits at the PTAB. While a discretionary denial prevents that specific petition from proceeding, it does not confirm the patent's strength against all prior art.

If considering an IPR defense, a prospective petitioner should carefully review the Director's decision for IPR2025-01322 (Paper No. not provided but would be available on the USPTO PTAB End-to-End system) to understand the precise discretionary grounds for denial and tailor any new petition to avoid similar issues. The USPTO PTAB Decisions portal would be the source for this document. It is also crucial to identify any ongoing or past district court litigation or other PTAB proceedings involving US10668430, as these "related proceedings" can significantly influence future institution decisions.

Inventors

• Edwin S. Olson (Employer: Likely Energy and Environmental Research Center Foundation at time of invention, based on assignment records)
• Michael J. Holmes (Employer: Likely Energy and Environmental Research Center Foundation at time of invention, based on assignment records; also acted as correspondent for multiple assignments)
• John H. Pavlish (Employer: Likely Energy and Environmental Research Center Foundation at time of invention, based on assignment records)

Original assignee

The entity named on the issued patent US10668430 is Midwest Energy Emissions Corp. Midwest Energy Emissions Corp (now known as ME2C Environmental and operating as Birchtech Corp) ships products embodying the claims, specifically sorbents for mercury removal. Its primary line of business is providing mercury emission control solutions and other environmental technologies. The company is currently operating, having changed its name to Birchtech Corp in 2024.

Assignment timeline

• 2019-09-23 (executed) / recorded 2019-09-27 — Reel 049382/0204

  • Conveyance: Assignment
  • Assignor: JOHN H. PAVLISH
  • Assignee: ENERGY AND ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Correspondent: MICHAEL J. HOLMES, ENERGY & ENVIRONMENTAL RESEARCH CENTER, 15 NORTH 23RD STREET, GRAND FORKS, ND 58202. This correspondent (Michael J. Holmes) recurs in this chain.
  • Context: Inventor assignment to research foundation

• 2019-09-23 (executed) / recorded 2019-09-27 — Reel 049382/0208

  • Conveyance: Assignment
  • Assignor: MICHAEL J. HOLMES
  • Assignee: ENERGY AND ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Correspondent: MICHAEL J. HOLMES, ENERGY & ENVIRONMENTAL RESEARCH CENTER, 15 NORTH 23RD STREET, GRAND FORKS, ND 58202. This correspondent (Michael J. Holmes) recurs in this chain.
  • Context: Inventor assignment to research foundation

• 2019-09-23 (executed) / recorded 2019-09-27 — Reel 049382/0212

  • Conveyance: Assignment
  • Assignor: EDWIN S. OLSON
  • Assignee: ENERGY AND ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Correspondent: MICHAEL J. HOLMES, ENERGY & ENVIRONMENTAL RESEARCH CENTER, 15 NORTH 23RD STREET, GRAND FORKS, ND 58202. This correspondent (Michael J. Holmes) recurs in this chain.
  • Context: Inventor assignment to research foundation

• 2019-09-23 (executed) / recorded 2019-09-27 — Reel 049382/0200

  • Conveyance: Assignment of Assignors Interest
  • Assignor: ENERGY AND ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Assignee: MIDWEST ENERGY EMISSIONS CORP.
  • Correspondent: MICHAEL J. HOLMES, ENERGY & ENVIRONMENTAL RESEARCH CENTER, 15 NORTH 23RD STREET, GRAND FORKS, ND 58202. This correspondent (Michael J. Holmes) recurs in this chain.
  • Context: Transfer from research foundation to operating company

• 2020-03-11 (executed) / recorded 2020-03-24 — Reel 050462/0607

  • Conveyance: Corrective Assignment
  • Assignor: ENERGY AND ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Assignee: MIDWEST ENERGY EMISSIONS CORP.
  • Correspondent: MICHAEL J. HOLMES, ENERGY & ENVIRONMENTAL RESEARCH CENTER, 15 NORTH 23RD STREET, GRAND FORKS, ND 58202. This correspondent (Michael J. Holmes) recurs in this chain.
  • Context: Corrective assignment to update assignee address

• 2024-11-07 (executed) / recorded 2024-11-20 — Reel 063636/0402

  • Conveyance: Change of Name
  • Assignor: MIDWEST ENERGY EMISSIONS CORP.
  • Assignee: BIRCHTECH CORP.
  • Correspondent: Matthew S. Frick, ME2C Environmental, LLC, 4656 EXECUTIVE DRIVE, COLUMBUS, OH 43220
  • Context: Corporate name change

Timeline diagram

timeline
    title Ownership of US 10668430
    2018 : Application filed by Midwest Energy Emissions Corp
    2019 : Inventors assigned to EERC Foundation
         : EERC Foundation assigned to Midwest Energy Emissions
    2020 : Corrective Assignment
         : Patent Issued
    2024 : Midwest Energy Emissions changed name to Birchtech Corp

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The assignees are a known research foundation (Energy and Environmental Research Center Foundation) and an operating company (Midwest Energy Emissions Corp / Birchtech Corp) that manufactures and sells products.
2. Known asserter in the chain — Not present. None of the listed assignees match known NPE lists like Acacia Research Corp or Marathon Patent Group.
3. Repeat correspondent across the chain — Present. Michael J. Holmes, an inventor, served as the correspondent for all four assignments executed on 2019-09-23 (Reel 049382/0200, 049382/0204, 049382/0208, 049382/0212) and the corrective assignment on 2020-03-11 (Reel 050462/0607). His recurrence is within the context of an inventor/in-house counsel for a research foundation and its commercialization partner.
4. Cascading transfers — Not present. The assignments executed on 2019-09-23 represent the initial formalization of the chain of title from inventors to the operating company via a research institution, not a series of rapid transfers between unrelated shell entities.
5. Pre-litigation transfer — Present. The first litigation case in the patent family (1:19-cv-01334) was filed on 2019-07-11. The assignments perfecting the chain of title for US10668430 from the inventors to Energy and Environmental Research Center Foundation and then to Midwest Energy Emissions Corp were executed later on 2019-09-23.
6. Bankruptcy fire-sale — Not present. There is no indication of bankruptcy proceedings for any of the entities involved in the assignment chain.
7. Privateering — Unclear. While the current owner is an operating company, the presence of litigation in the patent family prior to the formal assignments for this specific patent might suggest a strategy where assertion was contemplated or initiated while title was being perfected. However, without more information, it is not possible to confirm privateering.
8. Defensive aggregator (anti-NPE) — Not present. The patent has not been assigned to a known defensive aggregator like RPX or AST.

Verdict

Operating-company assertion
The patent chain shows transfers from individual inventors to a research foundation, and subsequently to Midwest Energy Emissions Corp (now Birchtech Corp), an operating company that manufactures products related to the patent claims. The "Pre-litigation transfer" signal is present as litigation in the patent family began before the formal assignments for this specific patent were executed (litigation started 2019-07-11; assignments executed 2019-09-23, recorded 2019-09-27). This timing suggests a commercial assertion strategy by an operating company, not typical NPE behavior involving shell entities or serial transfers.

Verification link: https://assignmentcenter.uspto.gov/

To identify the most relevant prior art for US patent 10668430, I will analyze the citations listed within the patent itself. The patent document on Google Patents provides a "Prior art keywords" section and lists "Other versions" and "Family has litigation" information, but for specific prior art citations, I need to examine the full patent text. The "References Cited" section within the full patent text details the prior art patents and publications that were considered by the patent examiner during prosecution.

I will go through the cited references in US10668430 and extract the requested information.

Most Relevant Prior Art for US Patent 10668430:

Based on the provided patent text, the following prior art references are cited:

U.S. Patent Documents:

• U.S. Pat. No. 3,194,629

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes porous beds containing a mercury oxidizing reagent on a solid support, specifically mentioning triiodide or other mixed halogens.
  • Potential Anticipation (35 U.S.C. § 102): This patent potentially anticipates claims related to the use of halogen-containing reagents for mercury oxidation on a sorbent. For example, it could be relevant to aspects of Independent Claim 1, which broadly covers a promoted carbon sorbent using halogens/halides for mercury removal, and Independent Claim 13, concerning the method of preparing such a sorbent. The specific mention of "triiodide or other mixed halogens" suggests a direct overlap with the concept of using halogens as promoters.

• U.S. Pat. No. 3,662,523

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes porous beds containing a mercury oxidizing reagent on a solid support, specifically mentioning triiodide or other mixed halogens.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 3,194,629, this patent potentially anticipates claims related to the use of halogen-containing reagents for mercury oxidation on a sorbent, specifically aspects of Independent Claim 1 and 13.

• U.S. Pat. No. 4,101,631

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes porous beds containing a mercury oxidizing reagent on a solid support, specifically mentioning sulfur.
  • Potential Anticipation (35 U.S.C. § 102): This patent might be relevant to claims that include mercury-stabilizing reagents like sulfur, as mentioned in various dependent claims and methods in US10668430. For instance, the method described in Independent Claim 17, particularly if further comprising adding a mercury-stabilizing reagent (as allowed by the description), could be anticipated in part.

• U.S. Pat. No. 4,708,853

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes porous beds containing a mercury oxidizing reagent on a solid support, specifically mentioning sulfur.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 4,101,631, this patent might anticipate aspects of claims involving mercury-stabilizing reagents such as sulfur.

• U.S. Pat. No. 4,786,483

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes porous beds containing a mercury oxidizing reagent on a solid support, specifically mentioning peroxomonosulfate.
  • Potential Anticipation (35 U.S.C. § 102): This reference anticipates the general concept of a mercury oxidizing reagent on a solid support, which is a broad feature of US10668430.

• U.S. Pat. No. 4,889,698

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions the collection of mercury chemisorbed to a sorbent particle from a gas stream in a bag house or ESP along with ash particulates.
  • Potential Anticipation (35 U.S.C. § 102): This patent could be relevant to the collection and separation steps described in Independent Claim 17 (collecting mercury on sorbent and substantially recovering sorbent) and Independent Claim 21 (separating sorbent particles from ash particles).

• U.S. Pat. No. 4,956,162

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions the collection of mercury chemisorbed to a sorbent particle from a gas stream in a bag house or ESP along with ash particulates.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 4,889,698, this patent could anticipate aspects of the collection and separation steps in Independent Claim 17 and 21.

• U.S. Pat. No. 5,505,766

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions the collection of mercury chemisorbed to a sorbent particle from a gas stream in a bag house or ESP along with ash particulates.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 4,889,698, this patent could anticipate aspects of the collection and separation steps in Independent Claim 17 and 21.

• U.S. Pat. No. 5,672,323

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions the collection of mercury chemisorbed to a sorbent particle from a gas stream in a bag house or ESP along with ash particulates.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 4,889,698, this patent could anticipate aspects of the collection and separation steps in Independent Claim 17 and 21.

• U.S. Pat. No. 5,827,352

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions the collection of mercury chemisorbed to a sorbent particle from a gas stream in a bag house or ESP along with ash particulates.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 4,889,698, this patent could anticipate aspects of the collection and separation steps in Independent Claim 17 and 21.

• U.S. Pat. No. 5,891,324

  • Full Citation: Nelson et al.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes an activated carbon containing an acid (HCl, H2SO4, or H3PO4) for the removal of mercury contained in a liquid phase, such as in the oil industry. The model presented was that mercury is adsorbed from the liquid into the solid carbon phase at relatively low temperatures.
  • Potential Anticipation (35 U.S.C. § 102): This patent is particularly relevant to Independent Claim 1 (promoted carbon sorbent) and 13 (method of preparing it) as it discusses acid-treated activated carbon for mercury removal. However, the current patent distinguishes itself by focusing on gas phase removal and specific halogen/halide promotion for oxidation, rather than liquid phase adsorption. The patent text explicitly states that the Nelson method "lacks many of the features described in this application that impart exceptional activity to the sorbent in a convenient way, for example, the addition of smaller amount of a second more powerful promoting agent, the use of facile solvent systems, including aqueous bromine, and the use of in-flight bromine treatment. Additionally, the patent application does not mention regeneration, recycling, or reuse, or the use of moving contactors or larger particle size to facilitate sorbent-ash separation."

• U.S. Pat. No. 6,027,551

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions the collection of mercury chemisorbed to a sorbent particle from a gas stream in a bag house or ESP along with ash particulates.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 4,889,698, this patent could anticipate aspects of the collection and separation steps in Independent Claim 17 and 21.

• U.S. Pat. No. 6,136,072

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes amalgamating noble metals (gold, silver) on a suitable support for mercury removal, which can be regenerated by microwave heating.
  • Potential Anticipation (35 U.S.C. § 102): This patent deals with mercury removal and regeneration, which are broad concepts in US10668430 (Independent Claim 17 and 21 implicitly, and the overall spirit of regenerable sorbents). However, the specific sorbent composition (noble metals) and regeneration method (microwave heating) differ from the halogen-promoted carbon and other regeneration techniques described in US10668430.

• U.S. Pat. No. 6,214,304

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions sodium sulfide particles as fine-particle injection sorbents for mercury removal.
  • Potential Anticipation (35 U.S.C. § 102): This patent is relevant to the general concept of injecting fine-particle sorbents for mercury removal, which is a feature of Independent Claim 17. However, the specific chemical nature of the sorbent (sodium sulfide vs. halogen-promoted carbon) differs.

• U.S. Pat. No. 6,258,334

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes porous beds containing a mercury oxidizing reagent on a solid support, specifically mentioning sulfur.
  • Potential Anticipation (35 U.S.C. § 102): Similar to U.S. Pat. No. 4,101,631, this patent might anticipate aspects of claims involving mercury-stabilizing reagents such as sulfur.

• U.S. Patent Application 2001/0003116

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: 2001/0003116
  • Brief Description: Describes the regeneration of a plate or honeycomb material composed of transition metal oxides used for sorption of mercury in flue gas. The process involves heating the sorbent in a reducing gas stream to remove poisons, followed by impregnation with a polyfunctional complex-forming reagent containing the catalyst active component to restore mercury capture capacity.
  • Potential Anticipation (35 U.S.C. § 102): This application is highly relevant to the regeneration and reuse aspects of US10668430, particularly those implied in Independent Claim 17 and 21. The method of regeneration described, though different in specific chemical components, shares the goal of restoring sorbent capacity after mercury capture.

• U.S. Patent Application 2002/0150516

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: 2002/0150516
  • Brief Description: Describes a process of injecting manganese oxide sorbent particles, with regeneration claimed by removal of spent oxide particles from the reaction zone and rinsing with dilute aqueous acid.
  • Potential Anticipation (35 U.S.C. § 102): This application directly addresses the injection of sorbent particles and their regeneration for mercury removal, making it relevant to Independent Claims 17 and 21 of US10668430. The specific sorbent material (manganese oxide) and regeneration method differ, but the overall functional concept is similar.

Foreign Patent Documents:

• Japanese Patent JP 49-43197

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes the treatment of Hg-contaminated electrolysis cell gas using a metal iodide salt on a support.
  • Potential Anticipation (35 U.S.C. § 102): This patent is relevant to the use of halides (iodide) for mercury removal, which could potentially anticipate aspects of Independent Claim 1 and 13. However, US10668430 specifies a carbon sorbent reacted with a halogen/halide to form a halide-modified carbon, differentiating it from a metal iodide salt on a support. The patent text explicitly states, "These patents do not appear to represent a carbon bromide compound as specified in this patent application."

• Japanese Patent JP 50-6438

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes a treatment using a resin impregnated with a metal iodide.
  • Potential Anticipation (35 U.S.C. § 102): Similar to JP 49-43197, this patent is relevant to halide-based mercury removal, but the resin-based support and metal iodide impregnation distinguish it from the carbon-halide reaction product of US10668430. The patent text explicitly states, "These patents do not appear to represent a carbon bromide compound as specified in this patent application."

• German Patent 34 26 059

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Describes the use of a very thick carbon bed for treatment of flue gases containing polyhalogenated compounds. The spent sorbent is burned and not regenerated, and the carbons are not pretreated.
  • Potential Anticipation (35 U.S.C. § 102): This patent uses a carbon bed for flue gas treatment, which is a broad area of overlap with US10668430. However, the critical differences lie in the pretreatment of the carbon and the regeneration aspect of US10668430, both of which are explicitly stated as absent in the German patent. Therefore, while it relates to carbon and flue gas treatment, it is unlikely to anticipate the specific promoted sorbent or regeneration methods of US10668430.

Other Publications:

• Ghorishi, B.; Gullet, B. K. Waste Manage Res. 1993, 16, 582.

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: 1993
  • Brief Description: Mentions basic silicate or oxide sorbents as fine-particle injection sorbents effective only for oxidized mercury.
  • Potential Anticipation (35 U.S.C. § 102): This publication is relevant to the broader field of fine-particle injection sorbents for mercury removal (Independent Claim 17), but the chemical nature of the sorbents (silicate/oxide vs. promoted carbon) and their effectiveness (only for oxidized mercury, whereas US10668430 addresses elemental mercury) differentiate it from the claimed invention.

• Lancia references

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: Mentions basic silicate or oxide sorbents as fine-particle injection sorbents effective only for oxidized mercury.
  • Potential Anticipation (35 U.S.C. § 102): Similar to the Ghorishi reference, this publication relates to fine-particle injection sorbents for oxidized mercury.

• Tsuji, K.; Shiraishi, I.; Dague, R. F. Proceedings, Sixth International Symposium, Air & Water Management Assoc., New Orleans, La., Mar. 10-12, 1993 (GE-Mitsui-BF system)

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: March 10-12, 1993
  • Brief Description: Describes the GE-Mitsui-BF system employing a recirculating carbon bed where mercury is removed along with acid gases, and the carbon is regenerated at high temperatures. Attrition of the sorbent results in significant cost, and the carbons are not pretreated.
  • Potential Anticipation (35 U.S.C. § 102): This reference is highly relevant to the concepts of carbon beds for mercury capture, recirculation, and regeneration, as broadly covered by Independent Claims 17 and 21. However, US10668430 distinguishes itself by the pretreatment of the carbon to create a halogen/halide-promoted sorbent and improved economics due to enhanced reactivity and regenerability. The patent text explicitly notes, "The carbons are not pretreated."

• Streng reference

  • Full Citation: Not fully available in the provided text.
  • Publication/Filing Date: Not explicitly stated in the provided text.
  • Brief Description: General mention of Hg removal.
  • Potential Anticipation (35 U.S.C. § 102): Too general to assess specific anticipation without further detail.

Most Relevant Prior Art Summary:

The most relevant prior art appears to be U.S. Pat. No. 5,891,324 (Nelson et al.) which describes acid-treated activated carbon for mercury removal, and the GE-Mitsui-BF system (Tsuji et al.) which discusses recirculating carbon beds with regeneration for mercury capture. Both deal with fundamental aspects of mercury removal using carbon sorbents and regeneration, but US10668430 explicitly identifies differences in its approach, such as the gas-phase application, specific halogen/halide promotion for oxidation, in-flight treatment, and the regenerability of the promoted sorbent, as well as the larger particle size for separation from ash. The Japanese patents on metal iodide salts on supports are also relevant due to the use of halides, but are distinguished by the composition of the sorbent. The German patent and the Ghorishi/Lancia references are more general in their scope concerning carbon beds and sorbent injection, respectively, and are distinguished by the lack of pretreatment or the specific type of mercury removed.

Obviousness Analysis under 35 U.S.C. § 103

A patent claim is obvious if "the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art" (35 U.S.C. § 103). This analysis identifies potential combinations of prior art that would render claims of US10668430 obvious.

A "person having ordinary skill in the art" (PHOSITA) in this field would likely be a chemical engineer or environmental engineer with experience in air pollution control, specifically mercury emissions, and familiarity with sorbent materials and their application in industrial gas streams.

Combination 1: Activated Carbon + Halide/Halogen Promotion (Claims 1, 13)

• References: General knowledge in the field, combined with references related to activated carbon and halogen/halide chemistry.

  • The patent itself acknowledges that "Fine-particle injection sorbents include activated carbon" and that "a halogen/halide promoted activated carbon sorbent is described that is highly effective for the removal of mercury from flue gas streams." This indicates that the base activated carbon and the concept of promoting it with halogens/halides were known or at least recognized prior to this invention, even if the specific mechanism or level of reactivity was a new finding.
  • The patent also states that "Chlorine treatment resulted in lower-activity carbons because the chloride anion was less effective in promoting the oxidation by stabilizing the developing positive charge on the mercury in the transition state for oxidation." This implies that chlorine treatment of carbons for mercury removal was already being explored, suggesting a motivation to explore other halogens like bromine.

• Motivation for Combination: A PHOSITA, aware of the general use of activated carbon for mercury removal and the potential for halogen species to enhance oxidation (as alluded to by existing chlorine treatments), would have been motivated to explore other, more reactive halogens or halides, such as bromine or bromide compounds, to improve the efficiency of mercury capture. The inherent chemical properties of halogens, particularly their oxidizing potential, would suggest that different halogens might yield varying levels of effectiveness when used to promote activated carbon. The goal would be to find a more effective and cost-efficient sorbent.

• Obviousness Argument: Claim 1 describes a promoted carbon sorbent formed by reacting activated carbon with a halogen or halide. Claim 13 describes a method of preparing such a sorbent. Given the existing knowledge of activated carbon for mercury removal and the known chemical reactivity of different halogens, it would have been obvious to a PHOSITA to experiment with reacting activated carbon with various halogens or halides (e.g., bromine, hydrogen bromide) to create a promoted sorbent. The patent's own discussion of the comparative effectiveness of chlorine versus bromine treatments supports the idea that such explorations were within the purview of a skilled artisan seeking improved performance.

Combination 2: Activated Carbon + Halide/Halogen Promotion + Regeneration/Reuse (Claims 1, 13, 17, 21)

• References: General knowledge of activated carbon and halogen/halide chemistry (as above), combined with:

  • U.S. Pat. No. 6,214,304 (sodium sulfide particles for mercury removal).
  • U.S. Pat. Nos. 4,889,698, 4,956,162, 5,672,323, 5,827,352, 6,027,551, and 5,505,766 (various patents related to mercury capture on sorbent particles and removal from gas streams in bag houses or ESPs).
  • German Patent 34 26 059 (use of thick carbon beds for flue gas treatment, where spent sorbent is burned, not regenerated).
  • GE-Mitsui-BF system (recirculating carbon bed where mercury is removed and carbon is regenerated at high temperatures).
  • U.S. Patent Application 2002/0150516 (injecting manganese oxide sorbent particles, with regeneration claimed by rinsing with dilute aqueous acid).
  • U.S. Pat. No. 5,607,496 (oxidation of mercury on a metal oxide sorbent bed, with high temperatures proposed for regeneration).
  • A recent U.S. Patent application (2001/0003116) (regeneration of transition metal oxide plates/honeycombs for mercury sorption).
  • U.S. Pat. No. 6,136,072 (amalgamating noble metals on a support, regenerable by microwave heating).

• Motivation for Combination: The desire to reduce costs and waste disposal problems associated with mercury removal processes has long motivated the development of regenerable sorbents. Many prior art references explicitly discuss regeneration or reuse of various sorbents, even if not specifically halogen-promoted activated carbon. A PHOSITA would have been motivated to combine the improved mercury capture efficiency of halogen/halide promoted activated carbon with known regeneration techniques to achieve a more economical and environmentally friendly process. The patent itself highlights that "further disposal reductions are obtainable by regenerating and reusing the sorbents produced using the inventive technology."

• Obviousness Argument: Claims 17 and 21 describe methods that include recovering and potentially re-injecting or regenerating the sorbent. Given the existing prior art that teaches various methods for regenerating and reusing different types of sorbents for pollution control (e.g., GE-Mitsui-BF system for carbon, U.S. Patent Application 2002/0150516 for manganese oxide, U.S. Pat. No. 6,136,072 for noble metals), it would have been obvious to a PHOSITA to apply these known regeneration principles to the newly developed (or optimized) halogen/halide-promoted activated carbon sorbents. The goal would be to extend the lifespan of the effective sorbent, thereby reducing operational costs and waste.

Combination 3: Halogen/Halide Promoted Activated Carbon with Enhanced Particle Size for Separation (Claims 1, 13, 21)

• References: Prior art related to activated carbon and halogen/halide chemistry (as above), combined with:

  • The patent explicitly states that "Standard AC sorbents generally are of fine size with a mean particle diameter of less than 20 micrometers, which is also typical of the flyash... Consequently, because the sizes of standard AC and flyash are similar, separation of the two is difficult." It then introduces the concept of a "treated larger particle sorbent" with a mass mean particle diameter "greater than about 40 micrometers."

• Motivation for Combination: The patent itself identifies the problem: the difficulty of separating fine activated carbon from fly ash for regeneration and reuse. A PHOSITA would be motivated to overcome this known challenge. The solution of using larger particles to facilitate physical separation (e.g., by sieving, density separation, or flotation) is a straightforward engineering approach to address the problem of separating materials of different sizes. This motivation is clearly articulated within the patent as a means to "substantially improve overall utilization and economics."

• Obviousness Argument: Claim 21 specifically addresses the use of activated carbon sorbent with a mass mean size greater than 40 micrometers to enable separation from ash particles based on size for re-injection. Once the benefit of a halogen-promoted activated carbon is established (as per Combination 1), and the problem of difficult separation from fly ash is recognized, it would be obvious to a PHOSITA to simply increase the particle size of the activated carbon to enable easier physical separation from the fly ash. This is a direct and logical solution to a clearly identified problem, especially given that larger particle sizes for sorbents were already contemplated (though perhaps not for enhanced activated carbons) to enable regeneration. The patent's own disclosure provides the motivation and the proposed solution.

Combination 4: Halogen/Halide Promoted Activated Carbon with Co-injected Alkali (Claims 1, 13, with additional features)

• References: Prior art related to activated carbon and halogen/halide chemistry (as above), combined with:

  • The patent states that "the efficiency of the activated carbons for mercury capture can be improved considerably by employing a basic material co-injected with the activated carbon, in order to capture any oxidized mercury that may be released from the sorbent, or to capture some of the sulfur or selenium oxides in the flue gas that can have a detrimental effect on the sorbent capacity." It further specifies "an optional alkaline material may preferably comprise calcium oxide, sodium carbonate, and the like, as are known in the art."
  • U.S. Pat. No. 6,214,304 (sodium sulfide particles, which are basic, for oxidized mercury).
  • Ghorishi and Lancia references (basic silicate or oxide sorbents effective for oxidized mercury).

• Motivation for Combination: A PHOSITA would be motivated to improve the overall mercury capture efficiency and sorbent capacity, especially in flue gas environments where other acidic components (SOx, NOx) can interfere. The patent explicitly states that "alkali acts to protect mercury binding sites and capture oxidized mercury, thereby resulting in improved mercury reduction at lower cost." Given that prior art already recognized the effectiveness of basic materials for oxidized mercury, it would be obvious to combine these known alkaline materials with the newly developed halogen-promoted activated carbon to achieve a synergistic effect, particularly for capturing oxidized mercury and mitigating interference from other flue gas contaminants.

• Obviousness Argument: While the independent claims (1 and 13) broadly cover the promoted carbon, other dependent claims and the specification detail the co-injection of an alkaline material. Given the existing knowledge of using basic materials (like metal oxides, sodium sulfide, calcium oxide) to capture oxidized mercury or other acidic flue gas components (as seen in U.S. Pat. No. 6,214,304 and the Ghorishi/Lancia references cited in the patent), a PHOSITA would find it obvious to combine these known alkaline materials with a halogen-promoted activated carbon. The goal would be to optimize mercury removal by addressing both elemental and oxidized mercury species and protecting sorbent sites from other contaminants, thereby enhancing overall system performance and potentially reducing cost.

In summary, the core concept of a halogen/halide promoted activated carbon, while potentially novel in its specific reactivity, builds upon existing knowledge of activated carbon as a sorbent and the chemical properties of halogens. The various applications and enhancements described in the claims (regeneration, larger particle size for separation, co-injection of alkali) represent logical and motivated combinations of the promoted carbon with widely known and previously disclosed techniques in the field of pollution control.