Midwest Energy Emissions Corp v. Evergy Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Midwest Energy Emissions Corp. (n/k/a Birchtech Corp.) (Delaware)
  • Defendant: Evergy, Inc., Evergy Metro, Inc., Evergy Missouri West, Inc., and Evergy Kansas Central, Inc. (Missouri, Delaware, Kansas)
  • Plaintiff’s Counsel: The Simon Law Firm, P.C.; Caldwell Cassady & Curry P.C.
• Case Identification: 4:25-cv-00050, W.D. Mo., 01/23/2025
• Venue Allegations: Venue is alleged based on Defendants' residence in the district and their operation of coal-fired power plants within the district, which constitute regular and established places of business where the alleged acts of infringement occurred.
• Core Dispute: Plaintiff alleges that Defendants’ operation of several coal-fired power plants infringes six patents related to methods for removing mercury from flue gas emissions.
• Technical Context: The technology addresses methods for controlling mercury pollution from coal combustion, a key regulatory requirement for power plants under federal environmental standards.
• Key Procedural History: The complaint notes that in a prior case in the District of Delaware, a jury found two of the patents-in-suit ('114 and '517) were willfully infringed by a third-party refined coal producer. Plaintiff also alleges it contacted Defendants on multiple occasions between 2016 and 2022 to discuss the patented technology and negotiate a license.

Case Timeline

Date	Event
2004-08-30	Earliest Patent Priority Date ('114, '225, '517, '430, '218, '370 Patents)
2016-01-01	Approximate MATS regulations compliance deadline
2016-08-02	Plaintiff alleges first pre-suit contact with Defendants regarding patented technology
2018-11-01	Plaintiff alleges second pre-suit contact with Defendants
2019-07-01	Approximate date Plaintiff filed Delaware case involving '114 and '517 Patents
2019-07-09	U.S. Patent No. 10,343,114 Issues
2019-08-07	Plaintiff alleges third pre-suit contact with Defendants, providing '114 Patent
2020-03-17	U.S. Patent No. 10,589,225 Issues
2020-03-24	U.S. Patent No. 10,596,517 Issues
2020-06-02	U.S. Patent No. 10,668,430 Issues
2021-02-23	U.S. Patent No. 10,926,218 Issues
2021-03-02	U.S. Patent No. 10,933,370 Issues
2022-02-08	Plaintiff alleges fourth pre-suit contact with Defendants regarding Patents-in-Suit
2024-03-01	Jury verdict in Delaware case finds willful infringement of '114 and '517 Patents
2025-01-23	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,343,114 - Sorbents for the Oxidation and Removal of Mercury

• Patent Identification: U.S. Patent No. 10,343,114, “Sorbents for the Oxidation and Removal of Mercury,” issued July 9, 2019.

The Invention Explained

• Problem Addressed: The patent addresses the problem that conventional methods for removing mercury from flue gas, such as injecting activated carbon, are inefficient and expensive. These methods require large amounts of sorbent, which is relatively unreactive toward elemental mercury, and contaminates the collected fly ash, complicating disposal and preventing reuse ( Compl. ¶¶ 45, 48; ’114 Patent, col. 2:3-20).
• The Patented Solution: The invention is a method for removing mercury by using a halogen/halide-promoted sorbent. A promoter (such as a bromine compound) is added to the coal before combustion or directly into the combustion chamber. This promoter reacts with a base sorbent (like activated carbon), which is injected downstream, to create a highly reactive surface that efficiently oxidizes and captures mercury from the flue gas ('114 Patent, col. 3:24-31, Abstract). The promoter enhances the sorbent's activity by forming complexes on its surface, which facilitates the oxidation and capture of mercury ('114 Patent, col. 3:12-21).
• Technical Importance: This approach is presented as a more economical and effective mercury removal technology that can meet regulatory standards with lower sorbent quantities, thereby reducing costs and waste ('114 Patent, col. 3:22-29).

Key Claims at a Glance

• The complaint asserts independent Claim 25 (Compl. ¶¶ 170-179).
• The essential elements of Claim 25 are:
  • A method of separating mercury from a mercury-containing gas.
  • Combusting coal in a combustion chamber to provide the gas, where the coal comprises an added bromine-based compound (Br₂, HBr, or bromide) added upstream, or the combustion chamber itself comprises such a compound.
  • Injecting a sorbent material comprising activated carbon into the gas downstream of the combustion chamber.
  • Contacting the mercury in the gas with the sorbent to form a mercury/sorbent composition.
  • Separating the mercury/sorbent composition from the gas to form a cleaned gas.
• The complaint states that Defendants infringe at least one of claims 1-30, thereby reserving the right to assert other claims, including dependent claims (Compl. ¶168).

U.S. Patent No. 10,589,225 - Sorbents for the Oxidation and Removal of Mercury

• Patent Identification: U.S. Patent No. 10,589,225, “Sorbents for the Oxidation and Removal of Mercury,” issued March 17, 2020.

The Invention Explained

• Problem Addressed: The patent addresses the same technical problem as the ’114 Patent: the inefficiency of prior art sorbents in capturing mercury, particularly elemental mercury, from coal combustion flue gas ('225 Patent, col. 2:3-20).
• The Patented Solution: The invention is a method for treating a mercury-containing gas by combusting a specific mixture. This mixture comprises coal, pyrolysis char, and an additive such as hydrogen bromide (HBr) or a bromide compound. This combustion forms the mercury-containing gas, into which a particulate sorbent of activated carbon is then added to capture the mercury ('225 Patent, Abstract, col. 1:44-51). The inclusion of pyrolysis char in the initial mixture is a distinct feature of this patented method.
• Technical Importance: This method claims to provide an effective way to treat mercury-containing gas generated from coal combustion, leveraging specific chemical additives and sorbents to achieve high capture efficiency ('225 Patent, col. 3:21-27).

Key Claims at a Glance

• The complaint asserts independent Claim 1 (Compl. ¶¶ 208-213).
• The essential elements of Claim 1 are:
  • A method for treating a mercury-containing gas.
  • Combusting a mixture comprising coal, pyrolysis char, and an additive (comprising HBr, a bromide compound, or a combination thereof) to form the gas.
  • Adding a particulate sorbent material comprising activated carbon into the mercury-containing gas.
• The complaint states that Defendants infringe at least one of claims 1-29, reserving the right to assert additional claims (Compl. ¶206).

U.S. Patent No. 10,596,517 - Sorbents for the Oxidation and Removal of Mercury

• Patent Identification: U.S. Patent No. 10,596,517, “Sorbents for the Oxidation and Removal of Mercury,” issued March 24, 2020.
• Technology Synopsis: The patent describes a method for reducing mercury in gas from coal combustion. The method involves combusting coal that contains a bromine-based additive (Br₂, HBr, or a bromide compound) and then collecting the resulting mercury with a sorbent comprising activated carbon that is added to the gas stream ('517 Patent, Abstract).
• Asserted Claims: Claim 1 (independent) (Compl. ¶¶ 191, 193, 195).
• Accused Features: The complaint alleges infringement by combusting coal with a bromine-based additive and then adding an activated carbon sorbent to the resulting flue gas to collect mercury (Compl. ¶¶ 194, 196).

U.S. Patent No. 10,668,430 - Sorbents for the Oxidation and Removal of Mercury

• Patent Identification: U.S. Patent No. 10,668,430, “Sorbents for the Oxidation and Removal of Mercury,” issued June 2, 2020.
• Technology Synopsis: The patent claims a method of separating mercury from gas by adding a bromine-based additive to the coal before it enters the combustion chamber. An activated carbon sorbent is then injected downstream to contact and separate the mercury ('430 Patent, Abstract).
• Asserted Claims: Claim 1 (independent) (Compl. ¶¶ 225, 227, 229, 231, 233).
• Accused Features: Defendants are accused of performing the patented method by combusting coal with a bromine-based additive, injecting activated carbon downstream, contacting the mercury with the sorbent, and separating the resulting composition (Compl. ¶¶ 228, 230, 232, 234).

U.S. Patent No. 10,933,370 - Sorbents for the Oxidation and Removal of Mercury

• Patent Identification: U.S. Patent No. 10,933,370, “Sorbents for the Oxidation and Removal of Mercury,” issued March 2, 2021.
• Technology Synopsis: This patent claims a mercury separation method involving combusting a mixture of coal and an additive (halides, halogens, or salts thereof). A key feature is adding a particulate activated carbon sorbent in a specific proportion: the weight ratio of the additive to the sorbent must be from about 1:100 to about 30:100 ('370 Patent, Abstract, Claim 1).
• Asserted Claims: Claim 1 (independent) (Compl. ¶¶ 246-255).
• Accused Features: Defendants are accused of combusting coal with halogen/halide additives and adding activated carbon sorbent where the weight ratio of additive to sorbent falls within the claimed 1:100 to 30:100 range (Compl. ¶¶ 249, 251).

U.S. Patent No. 10,926,218 - Sorbents for the Oxidation and Removal of Mercury

• Patent Identification: U.S. Patent No. 10,926,218, “Sorbents for the Oxidation and Removal of Mercury,” issued February 23, 2021.
• Technology Synopsis: This patent is similar to the '370 Patent but is directed specifically to iodine-based additives (HI, iodide salt, or combinations thereof). It also requires that the weight ratio of the iodine-based additive to the injected activated carbon sorbent be from about 1:100 to about 30:100 ('218 Patent, Abstract, Claim 1).
• Asserted Claims: Claim 1 (independent) (Compl. ¶¶ 267-276).
• Accused Features: The complaint alleges Defendants use iodine-based additives and activated carbon in a process where the weight ratio of additive to sorbent is within the claimed 1:100 to 30:100 range (Compl. ¶¶ 270, 272).

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are the mercury removal methods performed at coal-fired power plants owned and/or operated by the Defendants, identified as the Iatan, Hawthorn, La Cygne, Jeffrey Energy Center (JEC), and Lawrence generating stations (Compl. ¶¶ 70, 80, 87, 95, 103, 112).

Functionality and Market Context

• The complaint alleges that to comply with federal Mercury and Air Toxics Standards (MATS), these plants combust coal with an added bromine, bromide, iodine, iodide, or other halogen/halide compound. Downstream from the combustion chamber, a sorbent material comprising activated carbon is injected into the flue gas. The mercury binds to the activated carbon and is then collected in a particulate collection device, such as a baghouse or an electrostatic precipitator (ESP) (Compl. ¶¶ 111-112). The complaint asserts that Defendants rely on this technology to meet their regulatory obligations (Compl. ¶111).

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

U.S. Patent No. 10,343,114 Infringement Allegations

Claim Element (from Independent Claim 25)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method of separating mercury from a mercury-containing gas	Defendants allegedly perform this method at the Accused Coal Plants to comply with mercury regulations.	¶171	col. 5:35-42
combusting coal in a combustion chamber to provide the mercury-containing gas, wherein the coal comprises added Br₂, HBr, a bromide compound, or a combination thereof, added to the coal upstream of the combustion chamber, or the combustion chamber comprises added Br₂, HBr, a bromide compound, or a combination thereof, or a combination thereof	Defendants allegedly burn coal with an added bromine-based compound and/or add such a compound directly to the combustion chamber.	¶173	col. 2:31-35
injecting a sorbent material comprising activated carbon into the mercury containing gas downstream of the combustion chamber	Defendants allegedly inject an activated carbon sorbent downstream of the combustion chamber.	¶175	col. 3:40-44
contacting mercury in the mercury-containing gas with the sorbent, to form a mercury/sorbent composition	Mercury in the flue gas exiting the combustion chamber allegedly contacts the injected sorbent material.	¶177	col. 3:6-21
separating the mercury/sorbent composition from the mercury-containing gas, to form a cleaned gas	Defendants allegedly use equipment such as baghouses or electrostatic precipitators to collect the sorbent and captured mercury.	¶179	col. 2:3-10

U.S. Patent No. 10,589,225 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A method for treating a mercury-containing gas	Defendants allegedly perform this method at the Accused Coal Plants to comply with mercury regulations.	¶209	col. 2:21-26
combusting a mixture comprising coal, pyrolysis char, and an additive comprising HBr, a bromide compound, or a combination thereof, to form the mercury-containing, gas	Defendants allegedly combust coal, pyrolysis char, and a bromide-based additive.	¶211	col. 1:44-51
adding a particulate sorbent material comprising activated carbon into the mercury-containing gas	Defendants allegedly add a sorbent containing activated carbon to the gas that exits the combustion chamber.	¶213	col. 2:62-67

Identified Points of Contention

• Scope Questions: A central question for the ’225 Patent may be whether the accused process involves combusting a "mixture comprising coal, pyrolysis char, and an additive." The definition of "pyrolysis char" and whether it is combined with coal and an additive to form a "mixture" prior to or during combustion, as claimed, will likely be a point of dispute requiring claim construction and detailed factual evidence.
• Technical Questions: For the ’114 Patent, a factual question may arise regarding the point of introduction of the bromine-based additive. The claim requires addition "to the coal upstream of the combustion chamber" or addition such that "the combustion chamber comprises" the additive. Evidence of where and how Defendants introduce these additives will be critical. For the ’370 and ’218 Patents, a key evidentiary question will be whether the specific weight ratios of additive-to-sorbent alleged in the complaint (Compl. ¶¶ 251, 272) can be substantiated with evidence from Defendants' plant operations.

V. Key Claim Terms for Construction

The Term: "mixture comprising coal, pyrolysis char, and an additive" (’225 Patent, Claim 1)

• Context and Importance: This term is the central novel element of Claim 1 of the ’225 Patent. The infringement analysis will depend entirely on whether Plaintiff can prove that Defendants’ process involves the combustion of this specific three-component "mixture." Practitioners may focus on this term because the complaint's allegation that Defendants "combust coal, pyrolysis char, and an additive" (Compl. ¶211) is conclusory and does not specify how these components are mixed or if "pyrolysis char" is a distinct component in the accused process.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent does not appear to provide an explicit definition of the term. The background section discusses the combustion of fossil fuels generally, which could support an argument that "pyrolysis char" is an inherent byproduct of coal combustion and is thus always part of the "mixture" when an additive is present with the coal.
  • Evidence for a Narrower Interpretation: The term recites three distinct components ("coal, pyrolysis char, and an additive"), which suggests that each must be identifiably present in a pre-combustion "mixture." The detailed description does not provide specific examples of creating such a mixture, which could suggest the term should be limited to its plain and ordinary meaning, requiring proof of all three components being mixed.

The Term: "added to the coal upstream of the combustion chamber" (’114 Patent, Claim 25)

• Context and Importance: This term defines one of the two alternative locations for introducing the promoter. The infringement case for this portion of the claim depends on the physical location and method of Defendants' additive injection systems. Practitioners may focus on this term because the operational details of a power plant may present ambiguity as to what constitutes "upstream of the combustion chamber" versus inside it.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The specification does not provide a specific definition of "upstream." A party could argue it encompasses any point in the coal handling and preparation process before the burners, such as on conveyor belts or in pulverizers ('114 Patent, Fig. 6, "Additive Injection").
  • Evidence for a Narrower Interpretation: A party could argue the term implies addition to the coal as a distinct step before it enters the boiler system, potentially excluding introduction at or near the burners where combustion begins. The alternative claim language "or the combustion chamber comprises" the additive suggests "upstream" is a location meaningfully distinct from the chamber itself.

VI. Other Allegations

Indirect Infringement

• The complaint alleges that parent company Evergy, Inc. induces infringement by its operating subsidiaries. This inducement is allegedly based on Evergy's control over the subsidiaries and its role in approving and managing supply contracts for the activated carbon and bromine-containing additives required for the infringing process (Compl. ¶¶ 181, 198, 215). It also alleges that Defendants who co-own but do not operate plants induce the operators by directing and paying them to perform the patented methods to ensure regulatory compliance (Compl. ¶¶ 182, 199).

Willful Infringement

• Willfulness is alleged based on Defendants' purported knowledge of the patents-in-suit since at least August 2, 2016 (Compl. ¶154). The complaint alleges a multi-year history of communications where Plaintiff identified its patents and explained its technology to Defendants in attempts to negotiate a license (Compl. ¶¶ 153-157). The complaint also cites the March 1, 2024 jury verdict in the Delaware case, which found willful infringement of the '114 and '517 patents by a different entity, as further evidence of Defendants' knowledge and willful blindness (Compl. ¶¶ 69, 160-161).

VII. Analyst’s Conclusion: Key Questions for the Case

• A core issue will be one of claim scope and factual proof: can Plaintiff provide sufficient evidence to demonstrate that the complex operational processes inside Defendants' power plants meet the specific limitations of the asserted claims? This will turn on questions such as whether a "mixture comprising coal, pyrolysis char, and an additive" ('225 Patent) is actually formed and combusted, and whether the specific additive-to-sorbent weight ratios ('370 and '218 patents) are used.
• A second key issue will be claim construction: the dispute may center on the definition of key phrases like "upstream of the combustion chamber" ('114 Patent). The outcome of claim construction could determine whether the physical layout and processes at Defendants' facilities fall within the scope of the patent claims.
• Given the extensive pre-suit notice alleged in the complaint, a central legal question will be one of willfulness: did Defendants' continued use of the accused mercury control methods after being repeatedly notified of the patents and the technology constitute objective recklessness? The prior jury verdict on two of the patents-in-suit will likely be a significant factor in this analysis.