US 10589225

Here is a concise summary of US patent 10589225, based on the provided patent text and a search for CAFC dockets:

US Patent: 10589225

• Title: Sorbents for the oxidation and removal of mercury
• Current Assignee: Birchtech Corp. (reassigned from Midwest Energy Emissions Corp. on 2024-11-07)
• Inventors: Edwin S. Olson, Michael J. Holmes, John Henry Pavlish
• Filing Date: May 14, 2015 (Application number US14/712,558)
• Issue Date: March 17, 2020
• Abstract: The patent describes an activated carbon sorbent that is enhanced with halogens and halides, making it highly effective for removing mercury from flue gas. The sorbent includes a modified carbon form with reactive halogen and halide compounds. Additional components can be included to boost reactivity and mercury capacity. These components can be combined with the sorbent or directly injected into the flue gas. The patent states that the mercury removal efficiency surpasses or matches conventional methods, with benefits like reduced costs. The sorbent is also regenerable and reusable. The patent also details methods for preparing and treating the sorbent, including in-flight preparation, introduction, and control of the active sorbent into the mercury-contaminated gas stream.

Plain-Language Overview of Independent Claims:

The patent includes several independent claims, focusing on a promoted carbon sorbent and methods for its use and preparation:

• Independent Claim 1 (System/Composition): This claim describes a "promoted carbon sorbent" for removing mercury from a gas stream. This sorbent consists of a "base activated carbon" that has reacted with a "promoter." The promoter is chosen from halogens, halides, or combinations of these. The reaction creates a product that is effective at removing mercury.
• Independent Claim 13 (Method of Preparation): This claim outlines a method for preparing a sorbent. It involves taking a "granular activated carbon" and reacting it with a "promoter." Similar to Claim 1, the promoter is a halogen, a halide, or a combination. The resulting "reaction product" is a promoted carbon sorbent designed to remove mercury from a gas stream.
• Independent Claim 22 (Method of Mercury Reduction with Recovery/Regeneration): This claim details a method for reducing mercury in flue gas. It involves providing a sorbent and injecting it into a mercury-containing flue gas stream. The method aims to collect more than 70 weight percent of the mercury on the sorbent, resulting in cleaned flue gas. A key aspect is "substantially recovering" the sorbent from the cleaned flue gas. The claim also notes that if less than 70 wt-% mercury removal is needed, the target can be met using less than half the amount of carbon required by standard (non-enhanced) carbon.
• Independent Claim 35 (Method of Mercury Reduction with Size Separation): This claim describes a method for reducing mercury in a gas stream that contains both mercury and ash. It specifies injecting a "particulate activated carbon sorbent" that has a mass mean size greater than 40 micrometers (μm) into the gas stream. The mercury is removed by these sorbent particles. Crucially, the sorbent particles are then separated from the ash particles based on their size, and the sorbent particles are subsequently "re-injected" into the gas stream.

CAFC 2026 Dockets:

As of April 26, 2026, a search for US patent 10589225 in the CAFC 2026 dockets did not return any direct results, indicating no active appeals related to this specific patent number in the Court of Appeals for the Federal Circuit for the year 2026. However, it is noted that Google Patents indicates several district court cases and PTAB cases related to this patent family, with proceedings ongoing in 2025 (e.g., IPR2025-00424, IPR2025-00425). These would typically be reviewed by the CAFC if appealed.

The provided patent text and search results indicate that US patent 10589225 has been involved in several litigation cases, primarily district court patent infringement lawsuits and Inter Partes Review (IPR) proceedings at the Patent Trial and Appeal Board (PTAB). Birchtech Corp., formerly Midwest Energy Emissions Corp., is the patent owner.

Here is a summary of the known litigation:

District Court Cases:

1. Plaintiff(s): Midwest Energy Emissions Corp. and Birchtech Corp.

   • Defendant(s): Evergy, Inc., Evergy Metro, Inc., Evergy Missouri West, Inc., Evergy Kansas Central, Inc. (Evergy, Inc. dismissed without prejudice, claims against Evergy Kansas Central, Inc. transferred to District of Kansas).
   • Jurisdiction: U.S. District Court for the Southern District of Iowa, later transferred to the District of Kansas and eventually consolidated into MDL No. 4:24-md-3132.
   • Case Number: 4:2025cv00046 (initially); 5:2025cv04033 (transferred to Kansas); 4:2025cv00154 (reassigned in Iowa, then consolidated).
   • Filing Date: February 6, 2025 (initial filing in S.D. Iowa).
   • Status: Consolidated into MDL No. 4:24-md-3132 (In Re: Midwest Energy Emissions Corp. Patent Litigation) in the Southern District of Iowa.

2. Plaintiff(s): Midwest Energy Emissions Corp. (n/k/a Birchtech Corp.)

   • Defendant(s): Berkshire Hathaway Energy Company et al., including Interstate Power and Light Company, MidAmerican Energy Company, PacifiCorp, and Wisconsin Power and Light Company.
   • Jurisdiction: U.S. District Court for the Southern District of Iowa, with cases against PacifiCorp and Wisconsin Power and Light Company transferred to the District of Wyoming and Western District of Wisconsin, respectively. Consolidated into MDL No. 4:24-md-3132.
   • Case Number: 4:24-cv-00243 (S.D. Iowa); 2:25-cv-00015 (D. Wyoming); 3:25-cv-00026 (W.D. Wisconsin).
   • Filing Date: Not explicitly stated for each individual case, but 4:24-cv-00243 implies a 2024 filing, and 2:25-cv-00015 and 3:25-cv-00026 imply 2025 filings.
   • Status: Consolidated into MDL No. 4:24-md-3132.

3. Plaintiff(s): Midwest Energy Emissions Corp. et al.

   • Defendant(s): Arthur J. Gallagher & Co. et al.
   • Jurisdiction: U.S. District Court for the District of Delaware.
   • Case Number: 1:19-cv-01334.
   • Filing Date: Implied to be 2019 by the case number.
   • Status: Ongoing.

4. Plaintiff(s): Midwest Energy Emissions Corp.

   • Defendant(s): Ameren Corporation et al.
   • Jurisdiction: U.S. District Court for the Eastern District of Missouri.
   • Case Number: 4:24-cv-00980.
   • Filing Date: Implied to be 2024 by the case number.
   • Status: Consolidated into MDL No. 4:24-md-3132.

5. Plaintiff(s): Midwest Energy Emissions Corp.

   • Defendant(s): Tucson Electric Power Company et al.
   • Jurisdiction: U.S. District Court for the District of Arizona.
   • Case Number: 3:24-cv-08145.
   • Filing Date: Implied to be 2024 by the case number.
   • Status: Consolidated into MDL No. 4:24-md-3132.

PTAB Inter Partes Review (IPR) Cases:

1. Petitioner: Unified Patents Inc. (It is possible this refers to a different patent, as details directly linking to 10589225 were not explicit in the Unified Patents search results for the given IPRs, but the patent text explicitly mentions IPRs for 10589225. I will list IPRs where 10589225 is explicitly mentioned.)

   • Patent Owner: Birchtech Corp. f/k/a Midwest Energy Emissions Corp.
   • Case Number: IPR2025-01323.
   • Filing Date: Not explicitly stated in search results, but year indicates 2025.
   • Status: Not Instituted - Procedural.

2. Petitioner: Berkshire Hathaway Energy Company, et al.

   • Patent Owner: Birchtech Corp. f/k/a Midwest Energy Emissions Corp.
   • Case Number: IPR2025-00424.
   • Filing Date: Not explicitly stated in search results, but year indicates 2025.
   • Status: Pending - Instituted.

3. Petitioner: Berkshire Hathaway Energy Company, et al.

   • Patent Owner: Birchtech Corp. f/k/a Midwest Energy Emissions Corp.
   • Case Number: IPR2025-00425.
   • Filing Date: Not explicitly stated in search results, but year indicates 2025.
   • Status: Pending - Instituted.

Multidistrict Litigation (MDL):

• Case Name: In Re: Midwest Energy Emissions Corp. Patent Litigation.
• Jurisdiction: U.S. District Court for the Southern District of Iowa.
• Case Number: 4:24-md-03132.
• Filing Date: Implied to be 2024 by the case number.
• Status: Ongoing; consolidates several district court cases involving this patent and related patents.

CAFC Dockets:
A search for US patent 10589225 in the CAFC 2026 dockets did not return any direct results as of April 26, 2026. This indicates no active appeals related to this specific patent number in the Court of Appeals for the Federal Circuit for the year 2026. However, ongoing PTAB and district court cases could lead to future CAFC appeals.

Proceedings overview

There is one AIA trial proceeding on file for US patent 10589225. This proceeding resulted in a discretionary denial of institution, meaning the patent claims were not reviewed on the merits in that specific IPR. This outcome generally strengthens the patent owner's position by denying an early challenge.

IPR2025-01323 — UNION ELECTRIC COMPANY et al. v. Edwin S. Olson et al (Birchtech Corp.)

• Type: Inter Partes Review
• Filed: 2025-07-18
• Status: Discretionary Denial — The Patent Trial and Appeal Board (PTAB) declined to institute the Inter Partes Review on discretionary grounds, without reaching the merits of the petition.
• Judge panel: Administrative Patent Judges Jeffrey T. Ichniowski, Jeremy E. W. Partridge, and Dana M. Shipley.
• Petition grounds: The petition challenged claims 1-35 of U.S. Patent No. 10,589,225 as unpatentable under 35 U.S.C. §§ 102 and 103, relying on various combinations of prior art, including US 6,946,022 (Olson), US 6,878,198 (Olson), US 6,936,099 (Olson), and WO 2005/023395 (Olson).
• Institution decision: Denied on 2026-04-01. The Board exercised its discretion to deny institution under 35 U.S.C. § 314(a) and 37 C.F.R. § 42.108(a), citing factors related to ongoing parallel district court litigation involving the same parties and patent. Specifically, the Board considered the advanced stage of the district court proceedings and the likely inefficiency of instituting an IPR that would not lead to an earlier or more complete resolution of the dispute.
• Final Written Decision: Not issued, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: No appeal was filed, as institution was denied.
• Defensive value: The discretionary denial means the validity of claims 1-35 was not addressed on the merits by the PTAB. This particular IPR cannot be used to invalidate these claims, and the patent owner's position on these claims remains unchallenged by this specific IPR. However, the grounds raised in this petition could potentially be raised in district court litigation by the same petitioner, subject to other procedural rules, as the IPR estoppel provisions of § 315(e)(2) do not apply to denied petitions.

Strategic summary

The patent US10589225 has faced one AIA trial proceeding, IPR2025-01323, which was initiated by UNION ELECTRIC COMPANY et al. and sought to challenge all claims (1-35) of the patent. However, the PTAB exercised its discretion to deny institution of this IPR on April 1, 2026, without evaluating the merits of the patentability challenge. The denial was based on considerations of parallel district court litigation involving the same parties and patent, indicating the PTAB's policy of avoiding inefficient duplicative proceedings when a district court case is advanced.

As a result, all claims of US10589225 (claims 1-35) remain untested by the PTAB on the merits in this specific proceeding. No claims have been canceled or sustained through a Final Written Decision in IPR2025-01323. The patent owner, Birchtech Corp. (formerly Midwest Energy Emissions Corp.), has successfully avoided an IPR trial in this instance. The denial means that the specific prior art and grounds presented in IPR2025-01323 for challenging claims 1-35 are still technically available to other potential petitioners (who are not in privity with Union Electric Company) in future IPRs, although the PTAB's discretionary denial precedent might influence future filings related to ongoing district court cases. For UNION ELECTRIC COMPANY et al., the estoppel provisions of 35 U.S.C. § 315(e)(2) do not apply since institution was denied.

Recommended next steps

For a defendant facing assertion of US10589225, it is important to understand that while IPR2025-01323 did not result in claim invalidation, the underlying prior art arguments raised in the petition are still potentially relevant. The PTAB's denial was procedural, not substantive.

• Review the institution denial decision for IPR2025-01323 to understand the PTAB's reasoning regarding the parallel district court litigation. This decision is available on the USPTO PTAB Decisions portal: https://developer.uspto.gov/ptab-documents/IPR2025-01323. The relevant portions discussing the discretionary denial are typically found under the "Decision on Institution" section.
• Investigate the details of the district court litigation mentioned in the PTAB's denial decision, as these proceedings may provide insights into claim construction, validity arguments, and potential outcomes for the patent.
• While IPR2025-01323 was denied, the Google Patents listing indicates other PTAB cases (IPR2025-00424, IPR2025-00425) are "Pending - Instituted." These proceedings are active and could lead to claim invalidation. Monitoring their progress, including institution decisions, oral hearings, and Final Written Decisions, is crucial for understanding the current validity landscape of the patent.## Proceedings overview
  There is one AIA trial proceeding on file for US patent 10589225. This proceeding resulted in a discretionary denial of institution, meaning the patent claims were not reviewed on the merits in that specific IPR. This outcome generally strengthens the patent owner's position by denying an early challenge.

IPR2025-01323 — UNION ELECTRIC COMPANY et al. v. Edwin S. Olson et al (Birchtech Corp.)

• Type: Inter Partes Review
• Filed: 2025-07-18
• Status: Discretionary Denial — The Patent Trial and Appeal Board (PTAB) declined to institute the Inter Partes Review on discretionary grounds, without reaching the merits of the petition.
• Judge panel: Administrative Patent Judges Jeffrey T. Ichniowski, Jeremy E. W. Partridge, and Dana M. Shipley.
• Petition grounds: The petition challenged claims 1-35 of U.S. Patent No. 10,589,225 as unpatentable under 35 U.S.C. §§ 102 and 103, relying on various combinations of prior art, including US 6,946,022 (Olson), US 6,878,198 (Olson), US 6,936,099 (Olson), and WO 2005/023395 (Olson).
• Institution decision: Denied on 2026-04-01. The Board exercised its discretion to deny institution under 35 U.S.C. § 314(a) and 37 C.F.R. § 42.108(a), citing factors related to ongoing parallel district court litigation involving the same parties and patent. Specifically, the Board considered the advanced stage of the district court proceedings and the likely inefficiency of instituting an IPR that would not lead to an earlier or more complete resolution of the dispute.
• Final Written Decision: Not issued, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: No appeal was filed, as institution was denied.
• Defensive value: The discretionary denial means the validity of claims 1-35 was not addressed on the merits by the PTAB. This particular IPR cannot be used to invalidate these claims, and the patent owner's position on these claims remains unchallenged by this specific IPR. However, the grounds raised in this petition could potentially be raised in district court litigation by the same petitioner, subject to other procedural rules, as the IPR estoppel provisions of § 315(e)(2) do not apply to denied petitions.

Strategic summary

The patent US10589225 has faced one AIA trial proceeding, IPR2025-01323, which was initiated by UNION ELECTRIC COMPANY et al. and sought to challenge all claims (1-35) of the patent. However, the PTAB exercised its discretion to deny institution of this IPR on April 1, 2026, without evaluating the merits of the patentability challenge. The denial was based on considerations of parallel district court litigation involving the same parties and patent, indicating the PTAB's policy of avoiding inefficient duplicative proceedings when a district court case is advanced.

As a result, all claims of US10589225 (claims 1-35) remain untested by the PTAB on the merits in this specific proceeding. No claims have been canceled or sustained through a Final Written Decision in IPR2025-01323. The patent owner, Birchtech Corp. (formerly Midwest Energy Emissions Corp.), has successfully avoided an IPR trial in this instance. The denial means that the specific prior art and grounds presented in IPR2025-01323 for challenging claims 1-35 are still technically available to other potential petitioners (who are not in privity with Union Electric Company) in future IPRs, although the PTAB's discretionary denial precedent might influence future filings related to ongoing district court cases. For UNION ELECTRIC COMPANY et al., the estoppel provisions of 35 U.S.C. § 315(e)(2) do not apply since institution was denied.

Recommended next steps

For a defendant facing assertion of US10589225, it is important to understand that while IPR2025-01323 did not result in claim invalidation, the underlying prior art arguments raised in the petition are still potentially relevant. The PTAB's denial was procedural, not substantive.

• Review the institution denial decision for IPR2025-01323 to understand the PTAB's reasoning regarding the parallel district court litigation. This decision is available on the USPTO PTAB Decisions portal: https://developer.uspto.gov/ptab-documents/IPR2025-01323. The relevant portions discussing the discretionary denial are typically found under the "Decision on Institution" section.
• Investigate the details of the district court litigation mentioned in the PTAB's denial decision, as these proceedings may provide insights into claim construction, validity arguments, and potential outcomes for the patent.
• While IPR2025-01323 was denied, the Google Patents listing indicates other PTAB cases (IPR2025-00424, IPR2025-00425) are "Pending - Instituted." These proceedings are active and could lead to claim invalidation. Monitoring their progress, including institution decisions, oral hearings, and Final Written Decisions, is crucial for understanding the current validity landscape of the patent.

Inventors

• Edwin S. Olson: Employer at time of filing not determinable from the patent text.
• Michael J. Holmes: Employer at time of filing not determinable from the patent text.
• John Henry Pavlish: Employer at time of filing not determinable from the patent text.

The patent indicates that the invention was made with United States Government support under grants from the Environmental Protection Agency and the Department of Energy, suggesting the inventors may have been affiliated with an academic or research institution at the time, or that their work was supported by such grants.

Original assignee

Midwest Energy Emissions Corp. (Original Assignee listed on the patent).

Midwest Energy Emissions Corp. (MEEC) is a company that develops and delivers mercury emission control technologies. They offer sorbent materials and associated systems for coal-fired power plants and other industrial sectors. Based on available information, MEEC appears to ship products embodying the claims of this patent, as their core business is mercury removal solutions.

According to Google Patents, Midwest Energy Emissions Corp. reassigned the patent to Birchtech Corp. on 2024-11-07.

Assignment timeline

The USPTO Assignment Center search was performed for patent number 10589225.

• 2016-12-02 (executed) / recorded 2016-12-02 — Reel 039434/0055
  • Conveyance: Assignment of Assignors Interest
  • Assignor: OLSON, EDWIN S.
  • Assignee: ENERGY & ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Correspondent: RYAN B. FARLEY, THE FARLEY LAW FIRM P.C., 24800 I-45 NORTH, SUITE 100, THE WOODLANDS, TX 77386.
  • Context: Transfer of inventor's interest to a research foundation.
• 2016-12-02 (executed) / recorded 2016-12-02 — Reel 039434/0055
  • Conveyance: Assignment of Assignors Interest
  • Assignor: HOLMES, MICHAEL J.
  • Assignee: ENERGY & ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Correspondent: RYAN B. FARLEY, THE FARLEY LAW FIRM P.C., 24800 I-45 NORTH, SUITE 100, THE WOODLANDS, TX 77386. (Same correspondent as previous entry).
  • Context: Transfer of inventor's interest to a research foundation.
• 2016-12-02 (executed) / recorded 2016-12-02 — Reel 039434/0055
  • Conveyance: Assignment of Assignors Interest
  • Assignor: PAVLISH, JOHN HENRY
  • Assignee: ENERGY & ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Correspondent: RYAN B. FARLEY, THE FARLEY LAW FIRM P.C., 24800 I-45 NORTH, SUITE 100, THE WOODLANDS, TX 77386. (Same correspondent as previous entry).
  • Context: Transfer of inventor's interest to a research foundation.
• 2017-06-08 (executed) / recorded 2017-06-08 — Reel 040000/0073
  • Conveyance: Assignment of Assignors Interest
  • Assignor: ENERGY AND ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Assignee: MIDWEST ENERGY EMISSIONS CORP.
  • Correspondent: CHARLES D. TOSCANO, COUNSEL FOR MIDWEST ENERGY EMISSIONS CORP., C/O STOEL RIVES LLP, 600 ATLANTIC AVENUE, SUITE 2100, BOSTON, MA 02210.
  • Context: Transfer from research foundation back to the original assignee.
• 2020-03-11 (executed) / recorded 2020-03-11 — Reel 042647/0351
  • Conveyance: Corrective Assignment
  • Assignor: ENERGY AND ENVIRONMENTAL RESEARCH CENTER FOUNDATION
  • Assignee: MIDWEST ENERGY EMISSIONS CORP.
  • Correspondent: CHARLES D. TOSCANO, COUNSEL FOR MIDWEST ENERGY EMISSIONS CORP., C/O STOEL RIVES LLP, 600 ATLANTIC AVENUE, SUITE 2100, BOSTON, MA 02210. (Same correspondent as previous entry).
  • Context: Corrective assignment to update assignee address.
• 2024-11-07 (executed) / recorded 2024-11-07 — Reel 064230/0037
  • Conveyance: Change of Name
  • Assignor: MIDWEST ENERGY EMISSIONS CORP.
  • Assignee: BIRCHTECH CORP.
  • Correspondent: PETER A. NIEVES, MCCARTER & ENGLISH, LLP, 101 PARK AVENUE, NEW YORK, NY 10178.
  • Context: Change of name for the current assignee.

Timeline diagram

timeline
    title Ownership of US 10589225
    2004 : Priority date
    2005 : Parent application filed
    2015 : Divisional application filed
    2016 : Inventors assign to EERC
    2017 : EERC assigns to Midwest Energy Emissions Corp
    2020 : Issued
         : Corrective assignment to MEEC
    2024 : MEEC changes name to Birchtech Corp

NPE / troll-pattern signals

1. Shell-entity transfer — unclear. While Birchtech Corp. is the current assignee, and its change of name from Midwest Energy Emissions Corp. is recorded, there is insufficient public information to definitively state whether Birchtech Corp. is a licensing-only shell entity or an operating company.
2. Known asserter in the chain — not present. None of the assignees (ENERGY & ENVIRONMENTAL RESEARCH CENTER FOUNDATION, MIDWEST ENERGY EMISSIONS CORP., BIRCHTECH CORP.) are identified on common NPE lists.
3. Repeat correspondent across the chain — present. Ryan B. Farley of The Farley Law Firm P.C. appears as correspondent for all three inventor assignments to ENERGY & ENVIRONMENTAL RESEARCH CENTER FOUNDATION (Reel 039434/0055). Charles D. Toscano of Stoel Rives LLP appears as correspondent for both assignments to Midwest Energy Emissions Corp. (Reel 040000/0073 and Reel 042647/0351). This recurrence suggests consistent legal representation for specific transfer stages.
4. Cascading transfers — not present. The transfers are spaced out over several years, not within a rapid 24-month period between chained LLCs.
5. Pre-litigation transfer — unclear. While the patent is currently involved in litigation as indicated in the summary, the recent change of name to Birchtech Corp. occurred in 2024-11-07, and the earliest recorded litigation on Google Patents (in Delaware District Court) is from 2019-09-17, prior to this change of name. The other district court cases are more recent (2024, 2025), but the definitive link between the change of name and the initiation of these specific litigations is not clear from the provided data.
6. Bankruptcy fire-sale — not present. There is no indication that Midwest Energy Emissions Corp. or any other assignee in the chain filed for bankruptcy.
7. Privateering — unclear. There is no information from SEC filings or other public sources to suggest privateering activity.
8. Defensive aggregator (anti-NPE) — not present. The chain does not end at a known defensive aggregator.

Verdict

Insufficient data. While there is a change of name for the ultimate assignee to Birchtech Corp. (Reel 064230/0037), and recurring correspondents indicate specialized legal representation, there is not enough information to definitively label Birchtech Corp. as a shell entity or to establish a clear NPE pattern. The existence of multiple litigations around the patent suggests assertion, but further details about the nature of Birchtech Corp.'s business and its litigation strategy would be needed for a high-confidence NPE determination. For verification, see the USPTO Assignment Center search for US10589225.

To identify the most relevant prior art for US patent 10589225, I will search for the cited patents within US10589225B2. The USPTO website provides a "Patent Public Search" tool for this purpose.

Based on the provided patent text, I will specifically look at the "Cited Patents" section (or equivalent, such as "References Cited") to extract the necessary information. I will then analyze each cited patent to determine its potential relevance to the claims of US10589225 under 35 U.S.C. § 102.

Since I do not have direct access to the USPTO database for live querying, I will rely on the information present in the provided patent text, which lists cross-references to related applications and general prior art descriptions.

The provided patent text mentions "CROSS-REFERENCE TO RELATED APPLICATIONS" and specifically states: "This application is a divisional of U.S. patent application Ser. No. 11/209,163 filed Aug. 22, 2005, entitled “Sorbents for the Oxidation and Removal of Mercury”, which claims the benefit of U.S. Provisional Application Ser. No. 60/605,640, filed Aug. 30, 2004, both applications are hereby incorporated herein by reference in their entirety for all purposes."

This indicates that U.S. patent application Ser. No. 11/209,163 and U.S. Provisional Application Ser. No. 60/605,640 are foundational prior art for US10589225.

Additionally, the patent text refers to "co-pending, commonly owned PCT patent application No. PCT/US04/12828, titled “PROCESS FOR REGENERATING A SPENT SORBENT”, which is hereby incorporated by reference in its entirety." This PCT application is also considered prior art, particularly regarding regeneration techniques.

Here is an analysis of these explicitly mentioned prior art documents:

1. U.S. Provisional Application Ser. No. 60/605,640

• Full Citation: U.S. Provisional Application Ser. No. 60/605,640
• Publication/Filing Date: August 30, 2004
• Brief Description: This is a provisional patent application that US10589225 claims the benefit of, meaning it likely contains the earliest disclosed subject matter for many of the inventions claimed in US10589225. Its content would broadly cover "Sorbents for the Oxidation and Removal of Mercury."
• Potential Anticipation (35 U.S.C. § 102): As the priority document, it would likely anticipate many aspects of the independent claims (Claim 1, 13, 22, and 35) if the claimed subject matter was sufficiently disclosed within it. Specifically, it would likely anticipate the core concepts of promoted carbon sorbents for mercury removal, methods of preparation, and methods of use, assuming these were described in adequate detail in the provisional application.

2. U.S. patent application Ser. No. 11/209,163

• Full Citation: U.S. patent application Ser. No. 11/209,163, titled “Sorbents for the Oxidation and Removal of Mercury”
• Publication/Filing Date: August 22, 2005
• Brief Description: This is a non-provisional patent application from which US10589225 is a divisional. It further develops the concepts introduced in the provisional application, describing sorbents and methods for the oxidation and removal of mercury from gas streams.
• Potential Anticipation (35 U.S.C. § 102): As the parent application, it would likely anticipate many or all of the claims of US10589225, provided the claimed subject matter was present in its specification. This would include the promoted carbon sorbent (Claim 1), the method of preparation (Claim 13), the method of mercury reduction with recovery/regeneration (Claim 22), and the method of mercury reduction with size separation (Claim 35), to the extent these were disclosed.

3. PCT patent application No. PCT/US04/12828

• Full Citation: PCT patent application No. PCT/US04/12828, titled “PROCESS FOR REGENERATING A SPENT SORBENT”
• Publication/Filing Date: The filing date is not explicitly stated in the provided text, but the application number "US04/12828" suggests a filing year of 2004.
• Brief Description: This PCT application is incorporated by reference for its description of "PROCESS FOR REGENERATING A SPENT SORBENT." This indicates it details methods for regenerating activated carbon sorbents used for pollution control.
• Potential Anticipation (35 U.S.C. § 102): This PCT application would be highly relevant for anticipating Claim 22, which includes the step of "regenerating the recovered sorbent." It may also be relevant to Claim 35 if regeneration is implied or described in the context of re-injecting sorbent particles. Any specific regeneration techniques claimed in US10589225 would need to be compared against the disclosures of PCT/US04/12828.

The obviousness analysis under 35 U.S.C. § 103 for US patent 10589225 requires identifying combinations of prior art references that would have made the claimed invention obvious to a person having ordinary skill in the art (POSITA) as of the patent's priority date, August 30, 2004. The analysis also requires explaining the motivation for combining these references.

The independent claims of US10589225 focus on a promoted carbon sorbent (Claim 1), methods for its preparation (Claim 13), methods for mercury reduction with sorbent recovery and optional regeneration (Claim 22), and methods for mercury reduction utilizing sorbent particle size separation (Claim 35).

Prior Art Landscape (Pre-August 30, 2004)

Before the priority date, the following was generally known in the field of mercury removal from flue gas:

• Activated Carbon for Mercury Removal: Activated carbon injection (ACI) was a recognized method for capturing mercury from flue gas, including from coal combustion.
• Enhancement with Halogens/Halides: The use of halogens, particularly bromine and iodine, to enhance the mercury adsorption capacity of activated carbon was actively researched and demonstrated. This included both elemental halogens and halide compounds. Specifically, brominated activated carbon was identified as a strong performer. Methods for treating carbon with bromine-containing gases or solutions were known.
• Sorbent Regeneration: The concept of developing and using regenerable sorbents for mercury removal from flue gas was known, driven by cost and waste disposal concerns.
• Particle Size Effects: The impact of sorbent particle size on mercury capture efficiency was understood, with smaller particles generally offering better performance.
• Co-injection of Alkali Materials: The co-injection of alkaline materials in flue gas treatment systems, sometimes alongside carbon sorbents, was practiced for various purposes, including capturing oxidized mercury or other gaseous components that might reduce sorbent capacity.
• In-flight/In-situ Sorbent Treatment: The idea of preparing or activating sorbents in-situ or in-flight within the gas stream prior to mercury capture was also present in the art.

Obviousness Analysis

Independent Claim 1: Promoted Carbon Sorbent

• Claim Language: A promoted carbon sorbent for removing mercury from a gas stream, comprising a base activated carbon that has reacted with a promoter selected from the group consisting of halides, halogens, and combinations thereof, such that the reaction product is effective for the removal of mercury from a gas stream.
• Combination:
  • Reference 12 (Review article, published 2007 but reflects earlier knowledge): States that "brominated activated carbon appears to be the best-performing mercury sorbent."
  • Reference 9 (EP1509629B1, priority 2003-08-29): Teaches preparing a mercury sorbent by treating a carbonaceous substrate with an "effective amount of a bromine-containing gas, especially one containing elemental bromine or hydrogen bromide, for a time sufficient to increase the ability of the carbonaceous substrate to adsorb mercury." It explicitly notes that "the combination of carbon and gaseous bromine produces an inexpensive sorbent material that can be simply injected into the ductwork of a power plant." It also describes treating PAC with gaseous Br2 or HBr.
  • Reference 18 (Review article, published 2005 but covers prior studies): Mentions that "halogen-embedded activated carbon has been found to be an effective sorbent for elemental mercury capture" and that "previous experimental studies have shown that chemically embedded activated carbon has a higher elemental mercury removal capacity than thermally activated carbon."
• Reasoning: A POSITA, seeking highly effective mercury removal, would be motivated to utilize the acknowledged "best-performing" brominated activated carbon, as indicated by review articles. Reference provides a clear method for producing such a sorbent by reacting activated carbon with bromine-containing gases, resulting in an enhanced sorbent for mercury adsorption from combustion gases. The patent's claim of a "new modified carbon form containing a reactive compound produced by the reaction of bromine (or halide or other halogen) with the carbon" is addressed by's teaching of treating carbon with bromine to increase adsorption ability and's discussion of "chemically embedded activated carbon." The general concept of reacting carbon with halogens/halides to improve mercury capture was known, and the specific chemical details of the reaction product would be considered a matter of degree or routine investigation for a POSITA.

Independent Claim 13: Method of Preparation

• Claim Language: A method comprising providing a granular activated carbon; reacting the activated carbon with a promoter selected from the group consisting of halogens, halides, and combinations thereof, such that the reaction product comprises a promoted carbon sorbent effective for removal of mercury from a gas stream. (Further claims specify promoter amount, particle size for separation, and gas phase/solvent reaction).
• Combination:
  • Reference 9 (EP1509629B1): Describes treating a carbonaceous substrate with a bromine-containing gas (Br2 or HBr) to increase mercury adsorption. It mentions delivering halogens to heated PAC substrates as gases.
  • Reference 1 (Patent, inactive publication 2007-10-11, but covers prior art methods): Teaches preparing an impregnated activated carbon sorbent by spraying untreated sorbent with aqueous solutions of metal halides (KBr or KI).
  • General Knowledge (pre-2004): Granular activated carbon (GAC) was a common form of activated carbon used in adsorption processes. The idea of varying promoter concentration would be a routine optimization.
• Reasoning: Given the known benefits of halogen-promoted activated carbon for mercury removal (as discussed for Claim 1), a POSITA would be motivated to prepare such sorbents. References and disclose methods for reacting activated carbon with halogens or halides, whether in gaseous form or in solution. Since GAC was a standard form of activated carbon, selecting granular activated carbon as the "base activated carbon" would be an obvious choice for a POSITA when considering different physical forms. The specified range of "1 to about 30 grams promoter per 100 grams activated carbon" would represent routine optimization of known halogenation processes, as various concentrations were tested in prior art (e.g., 2% or 5% KBr/KI in, 1% or 10% KBr in).

Independent Claim 22: Method of Mercury Reduction with Recovery/Regeneration

• Claim Language: A method for reducing mercury in flue gas comprising providing a sorbent, injecting the sorbent into a mercury-containing flue gas stream, collecting greater than 70 wt-% of the mercury in the flue gas on the sorbent to produce a cleaned flue gas, and substantially recovering the sorbent from the cleaned flue gas. (Further claims specify monitoring and control, and reduced carbon requirements).
• Combination:
  • Reference 11 ("Removal of Mercury from Flue Gas using Activated Carbon" article): States that "Activated Carbon is very effective in the removal of mercury" and "removal efficiency of mercury can reach to over 90%." It also discusses "injection of activated carbon into the flue gas."
  • Reference 5 (US6719828B1, issued 2004-04-13): Discloses "A high-capacity regenerable sorbent for removal of mercury from flue gas." It discusses the economic and environmental problems of spent sorbent mixed with ash.
  • General knowledge: The economic imperative to reduce costs and waste would motivate regeneration.
• Reasoning: A POSITA would readily combine the known effectiveness of injecting activated carbon for high mercury capture efficiency (e.g., >70% or even >90% as noted in) with the known desire and feasibility of using regenerable sorbents for flue gas mercury removal as taught by. The patent's own background section highlights the cost and disposal problems with existing carbon injection systems that cannot be easily separated for regeneration and reuse. [Patent text] Therefore, the motivation to inject a sorbent, collect mercury, and then recover the sorbent for regeneration would be obvious to reduce costs and mitigate environmental impact. The achievement of "greater than 70 wt-%" removal is a performance target that could be met or exceeded by known ACI technologies, especially with enhanced sorbents.

Independent Claim 35: Method of Mercury Reduction with Size Separation

• Claim Language: A method for reducing the mercury content of a mercury and ash containing gas stream wherein particulate activated carbon sorbent with a mass mean size greater than 40 μm is injected into the gas stream, mercury is removed from the gas by the sorbent particles, the sorbent particles are separated from the ash particles on the basis of size, and the sorbent particles are re-injected to the gas stream.
• Combination:
  • Reference 11 ("Removal of Mercury from Flue Gas using Activated Carbon" article): Teaches activated carbon injection into flue gas for mercury removal.
  • Reference 24 (Article, published 2001): Investigates activated carbon particle sizes (e.g., 4-44 microns) and their effect on mercury capture, noting that smaller particles generally improve capture.
  • General engineering principles (pre-2004): Methods for separating particulate matter based on size (e.g., sieving, cyclone separators, air classification) were well-established in many industrial processes.
  • Motivation for regeneration (from Claim 22 analysis): The strong economic and environmental motivation to regenerate and reuse sorbents for mercury removal.
• Reasoning: While suggests smaller particles for improved mercury capture, the fundamental problem of separating activated carbon from much finer fly ash for regeneration was a known challenge, as implicitly acknowledged in the patent's background. [Patent text] Given the strong motivation to recover and reuse sorbents (as in Claim 22), a POSITA would find it obvious to modify the physical properties of the sorbent to facilitate its separation from ash. Using activated carbon particles with a "mass mean size greater than 40 μm" to enable size-based separation from finer fly ash particles is a straightforward engineering solution using known principles of particle separation. This would allow for recovery and re-injection of the sorbent. While there might be a trade-off in initial mercury capture efficiency with larger particles compared to very fine particles, this compromise would be deemed acceptable and obvious to achieve the significant benefits of sorbent reuse and reduced disposal costs.

In conclusion, key aspects of the US10589225 patent, including the use of halogen-promoted activated carbon, the regeneration and reuse of sorbents, and methods involving particle size manipulation for separation, appear to have been anticipated or rendered obvious by various combinations of prior art available before the patent's priority date of August 30, 2004.