DCT

4:25-cv-00050

Midwest Energy Emissions Corp v. Evergy Inc

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I. Executive Summary and Procedural Information

Midwest Energy Emissions Corp. v. Evergy, Inc.

  • Parties & Counsel:
  • Case Identification: 4:25-cv-00050, W.D. Mo., 01/23/2025
  • Venue Allegations: Venue is alleged to be proper as Defendants reside in the district, have committed acts of infringement at regular and established places of business (specifically named coal-fired power plants) within the district, and/or operate as agents or alter egos of entities residing in the district.
  • Core Dispute: Plaintiff alleges that Defendants' operation of coal-fired power plants infringes six patents related to mercury emission control systems that use halogen-based additives and sorbent injection.
  • Technical Context: The technology addresses the removal of mercury, a toxic pollutant, from the flue gas of coal combustion facilities, a key area of environmental regulation for the power generation industry.
  • Key Procedural History: The complaint notes that Plaintiff previously obtained a favorable jury verdict in the District of Delaware against a refined coal producer for contributory and induced infringement of two of the patents-in-suit ('114 and '517 patents), which implicitly required a finding of direct infringement by the power plants supplied by that producer. The complaint also alleges multiple pre-suit attempts by Plaintiff to license the patented technology to Defendants, beginning in 2016.

Case Timeline

Date Event
2004-08-30 Earliest Patent Priority Date
2016-04-01 Alleged period of infringement begins (based on MATS compliance deadline)
2016-08-02 Plaintiff allegedly first contacted Defendants regarding licensing
2018-11-01 Plaintiff allegedly contacted Defendants regarding licensing
2019-07-09 U.S. Patent No. 10,343,114 Issued
2019-08-07 Plaintiff allegedly contacted Defendants regarding licensing and the '114 patent
2020-03-17 U.S. Patent No. 10,589,225 Issued
2020-03-24 U.S. Patent No. 10,596,517 Issued
2020-06-02 U.S. Patent No. 10,668,430 Issued
2021-02-23 U.S. Patent No. 10,926,218 Issued
2021-03-02 U.S. Patent No. 10,933,370 Issued
2022-02-08 Plaintiff allegedly contacted Defendants regarding licensing
2024-03-01 Jury verdict in Plaintiff's favor in separate Delaware litigation
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”

The Invention Explained

  • Problem Addressed: The patent specification describes that existing methods for removing mercury from flue gas, such as injecting fine carbon sorbent particles, are often inefficient and costly. These sorbents are "relatively unreactive toward mercury," requiring large quantities that are expensive, difficult to separate from valuable fly ash, and create solid waste disposal problems (’114 Patent, col. 2:11-19).
  • The Patented Solution: The invention is a method for mercury removal using a "halogen/halide-promoted sorbent" (’114 Patent, col. 3:40-41). The method involves adding a promoter, such as a bromine compound, into the combustion system, which reacts with a base sorbent like activated carbon to make it more chemically reactive to mercury. This enhanced reactivity allows the sorbent to more effectively oxidize elemental mercury and capture it from the flue gas stream, even with short contact times (’114 Patent, Abstract; col. 3:53-61). Figure 6 of the patent illustrates a typical power plant layout where additives and sorbents are injected into the flue gas stream after the boiler but before collection devices like a baghouse or ESP (’114 Patent, Fig. 6).
  • Technical Importance: This approach sought to improve the economic and technical efficiency of mercury capture, a process mandated by environmental regulations for coal-fired power plants (’114 Patent, col. 1:36-45).

Key Claims at a Glance

  • The complaint asserts infringement of at least one of claims 1-30, with Claim 25 identified as exemplary (Compl. ¶¶168-169).
  • Independent Claim 25 includes the following essential elements:
    • A method of separating mercury from a mercury-containing gas.
    • Combusting coal in a combustion chamber to provide the gas, where either the coal or the combustion chamber itself comprises an added bromine-based compound (Br2, HBr, or a bromide 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 reserves the right to assert other claims, which may include dependent claims (Compl. ¶168).

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

The Invention Explained

  • Problem Addressed: Similar to its parent '114 patent, the specification states that conventional carbon injection systems for mercury removal are inefficient, requiring high sorbent-to-mercury ratios, which increases costs and creates waste disposal issues (’517 Patent, col. 2:11-19).
  • The Patented Solution: The patent describes a method to reduce mercury by using a halogen/halide to promote the reactivity of a sorbent. An additive containing bromine is introduced with the coal into the combustion chamber, which creates a mercury-containing flue gas. A sorbent such as activated carbon is then added to this gas to collect the mercury (’517 Patent, Abstract; col. 3:49-54). Figure 3 of the patent provides a schematic of a mercury control system, showing reservoirs for a base sorbent and a promoter that can be injected into a flue gas stream upstream of a particulate separator (’517 Patent, Fig. 3).
  • Technical Importance: The technology aimed to provide a more cost-effective and efficient process for power plants to meet regulatory requirements for mercury emissions (’517 Patent, col. 1:33-42).

Key Claims at a Glance

  • The complaint asserts infringement of at least one of claims 1-30, with Claim 1 identified as exemplary (Compl. ¶¶189-190).
  • Independent Claim 1 includes the following essential elements:
    • A method for reducing mercury in a mercury-containing gas.
    • Combusting coal in a combustion chamber, where the coal comprises an additive (Br2, HBr, a bromide compound, or combination thereof), to form the mercury-containing gas.
    • Collecting mercury from the gas using a sorbent comprising activated carbon that is added to the gas.
  • The complaint reserves the right to assert other claims (Compl. ¶189).

Multi-Patent Capsule

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

  • Technology Synopsis: This patent discloses a method for treating mercury-containing gas by combusting a mixture of coal, pyrolysis char, and a bromine-based additive. A particulate sorbent of activated carbon is then added to the resulting gas to capture the mercury (’225 Patent, Abstract; Claim 1).

  • Asserted Claims: At least one of claims 1-29, with Claim 1 as exemplary (Compl. ¶¶206-207).

  • Accused Features: The complaint alleges infringement by the combustion of coal and a bromine-based additive, followed by the addition of an activated carbon sorbent into the resulting gas (Compl. ¶¶211, 213).

  • Patent Identification: U.S. Patent No. 10,668,430 (“’430 Patent”), “Sorbents for the Oxidation and Removal of Mercury,” issued June 2, 2020.

  • Technology Synopsis: The patent describes a method of separating mercury from gas by combusting coal that contains a bromine-based additive. A sorbent comprising activated carbon is then injected downstream to contact and separate the mercury from the gas stream (’430 Patent, Abstract; Claim 1).

  • Asserted Claims: At least one of claims 1-29, with Claim 1 as exemplary (Compl. ¶¶223-224).

  • Accused Features: The alleged infringement involves combusting coal with a bromine additive and subsequently injecting an activated carbon sorbent downstream of the combustion chamber (Compl. ¶¶228, 230).

  • Patent Identification: U.S. Patent No. 10,933,370 (“’370 Patent”), “Sorbents for the Oxidation and Removal of Mercury,” issued March 2, 2021.

  • Technology Synopsis: This patent claims a method for mercury separation by combusting coal with an additive chosen from halides, halogens, or salts thereof. A key element is adding a particulate activated carbon sorbent in a specific weight ratio relative to the additive (from about 1:100 to about 30:100) to form and separate a mercury-sorbent composition (’370 Patent, Abstract; Claim 1).

  • Asserted Claims: At least one of claims 1-29, with Claim 1 as exemplary (Compl. ¶¶244-245).

  • Accused Features: The Defendants are accused of combusting coal with a halide/halogen additive and adding activated carbon in a manner that satisfies the claimed weight ratio (Compl. ¶¶249, 251).

  • Patent Identification: U.S. Patent No. 10,926,218 (“’218 Patent”), “Sorbents for the Oxidation and Removal of Mercury,” issued February 23, 2021.

  • Technology Synopsis: This patent is similar to the ’370 patent but focuses specifically on iodine-based additives (HI, iodide salt, or a combination). It claims a method of separating mercury by combusting coal with an iodine-based additive and injecting an activated carbon sorbent downstream, also within a specified weight ratio of additive to sorbent (from about 1:100 to about 30:100) (’218 Patent, Abstract; Claim 1).

  • Asserted Claims: At least one of claims 1-26, with Claim 1 as exemplary (Compl. ¶¶265-266).

  • Accused Features: The complaint alleges, in the alternative, that Defendants use iodine-based compounds as the additive and activated carbon in a process that meets the claimed weight ratio (Compl. ¶¶100, 107, 270, 272).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are the processes for mercury emission control employed at coal-fired power plants owned and/or operated by the Defendants, including the Iatan Generating Station, Hawthorn Station, La Cygne Generating Station, Jeffrey Energy Center, and Lawrence Energy Center (collectively, the "Accused Coal Plants") (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"), the Accused Coal Plants perform a multi-step method for mercury removal (Compl. ¶111). This allegedly involves combusting coal with an added halogen or halide (such as a bromine or iodine compound) in a combustion chamber (Compl. ¶¶76-77, 83-84, 91-92, 99-100, 106-107). Subsequently, a sorbent material comprising activated carbon is injected into the flue gas downstream of the combustion chamber (Compl. ¶¶78, 85, 93, 101, 108). Finally, the mercury, which has bound to the sorbent, is collected using a particulate collection device such as a baghouse or an electrostatic precipitator (ESP) (Compl. ¶¶79, 86, 94, 102, 109). The complaint's attached patent exhibits include a schematic diagram of a coal-fueled power plant illustrating the relative locations of the boiler (combustion chamber), sorbent injection points, and particulate collection equipment like a baghouse or ESP (e.g., ’114 Patent, Fig. 6).

IV. Analysis of Infringement Allegations

10,343,114 Patent 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 perform this method at the Accused Coal Plants to comply with mercury regulations. ¶171 col. 3:53-55
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… Defendants burn coal with an added bromine-based compound, or add such a compound directly to the combustion chamber. ¶173 col. 18:31-44
injecting a sorbent material comprising activated carbon into the mercury containing gas downstream of the combustion chamber Defendants inject activated carbon sorbent into the flue gas after it exits the combustion chamber. ¶175 col. 18:14-25
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 contacts the injected sorbent material. ¶177 col. 7:43-48
separating the mercury/sorbent composition from the mercury-containing gas, to form a cleaned gas Defendants use baghouses or electrostatic precipitators to collect the mercury captured by the sorbent from the gas stream. ¶179 col. 2:5-10
  • Identified Points of Contention:
    • Factual Questions: A primary factual question will be what specific chemical "additive" is used at each accused plant and where precisely it is introduced into the system. The complaint alleges bromine or iodine compounds are added either to the coal or directly into the combustion chamber (Compl. ¶¶76-77, 91-92). Evidence of the exact operational parameters will be necessary to determine if they fall within the claim's scope.
    • Scope Questions: Claim 25 covers adding a bromine compound to the coal "upstream of the combustion chamber" OR the "combustion chamber comprises" the added compound. A potential area of dispute could be the interpretation of these alternatives. For instance, what is the boundary of the "combustion chamber," and what does it mean for the chamber to "comprise" an added compound, as opposed to having the compound added directly to the coal feed?

10,596,517 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method for reducing mercury in a mercury-containing gas Defendants' operation of the Accused Coal Plants performs this method to meet federal and state mercury regulations. ¶192 col. 3:49-51
combusting coal in a combustion chamber, the coal comprising an additive comprising Br2, HBr, a bromide compound, or a combination thereof, to form the mercury-containing gas Defendants combust coal that has been treated with an additive containing a bromine-based compound. ¶194 col. 23:10-16
collecting mercury in the mercury-containing gas with a sorbent added to the mercury-containing gas, the sorbent comprising activated carbon Defendants add an activated carbon sorbent to the flue gas, which is then collected in equipment such as baghouses or electrostatic precipitators. ¶196 col. 2:4-10
  • Identified Points of Contention:
    • Technical Questions: The infringement allegation hinges on whether the coal combusted by Defendants "compris[es] an additive" as recited in the claim (Compl. ¶194). This raises the question of how the additive is incorporated. Is it pre-treated on the coal, or is it added separately but simultaneously with the coal feed? The evidence on how Defendants source and handle their coal and additives will be central.
    • Scope Questions: The term "collecting mercury... with a sorbent" is broad. A potential point of contention may be whether the Defendants' process of adding a sorbent and then capturing it in a downstream particulate control device constitutes "collecting... with" the sorbent as required by the claim, or if the claim implies a more direct or integrated collection mechanism.

V. Key Claim Terms for Construction

  • The Term: "downstream of the combustion chamber" (’114 Patent, Claim 25)

  • Context and Importance: This term defines the location for injecting the activated carbon sorbent. Its construction is critical because the location of injection determines the temperature, gas composition, and contact time the sorbent experiences, all of which are central to the patented method's effectiveness. Practitioners may focus on this term because a defendant could argue its injection point (e.g., after an air pre-heater or economizer) is not "downstream" in the manner disclosed and claimed by the patent.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The specification's general description and figures suggest "downstream" could mean any point after the primary combustion zone but before the particulate collection device. Figure 6 shows "Sorbent Injection" occurring after the "Boiler" but before the "Baghouse or ESP" (’114 Patent, Fig. 6).
    • Evidence for a Narrower Interpretation: Specific embodiments or descriptions of optimal temperature ranges for injection could be cited to argue for a narrower construction limited to certain zones. For example, the patent notes that some prior art methods require "appropriate high temperatures to heat the impregnated salt(s)," a problem the invention aims to solve, suggesting the invention operates at different, potentially lower, downstream temperatures (’114 Patent, col. 2:41-44).

  • The Term: "the coal comprising an additive" (’517 Patent, Claim 1)

  • Context and Importance: This term is central to the infringement analysis for the '517 patent, as it defines how the halogen promoter is introduced. The dispute will likely center on whether the additive must be pre-mixed with or applied to the coal before combustion, or if co-injection of the additive and coal into the chamber satisfies this limitation.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The claim language itself does not specify how the coal comes to "comprise" the additive, which could support a reading that includes simultaneous injection of separate streams of coal and additive into the combustion chamber.
    • Evidence for a Narrower Interpretation: The specification discusses adding bromine-based additives "onto coal" (Compl. ¶50). Language describing the treatment of coal with additives prior to combustion could be used to argue that the term requires the additive to be physically incorporated into or onto the coal before it enters the furnace, rather than simply being co-present in the combustion chamber.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges that the parent company, Evergy, Inc., induces infringement by its operating subsidiaries (Compl. ¶114). The alleged inducing acts include exercising technical and administrative control, and participating in and approving supply contracts for the bromine-containing additives and activated carbon that are used in the infringing processes (Compl. ¶¶115, 181, 198).
  • Willful Infringement: Willfulness is alleged based on pre-suit knowledge of the patents-in-suit (Compl. ¶160). The complaint asserts that Plaintiff contacted Defendants on multiple occasions beginning in August 2016 to discuss the patented technology, sending lists of patents, copies of patents, and explaining the scope of the patented methods (Compl. ¶¶154-157). The jury verdict in the prior Delaware litigation concerning the ’114 and ’517 patents is also a potential source of knowledge (Compl. ¶¶65-69).

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

  • A key evidentiary question will be one of "process specifics": what is the precise chemical composition of the additives used at the Accused Coal Plants, where are they introduced into the system, and in what quantities, particularly concerning the weight ratio limitations recited in the ’370 and ’218 patents?
  • A central legal issue will concern "joint liability and inducement": can the Plaintiff prove that parent company Evergy, Inc. exercised sufficient direction and control over its operating subsidiaries to establish liability for induced infringement, or that the various defendant entities operated as a joint enterprise as alleged?
  • A primary question for claim construction will be one of "temporal and spatial scope": does the claim language requiring sorbent injection "downstream of the combustion chamber" and coal "comprising an additive" require specific locations or timings of introduction, or can it be read broadly to cover the Defendants' actual operational configurations?