Midwest Energy Emissions Corp v. Ameren Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Midwest Energy Emissions Corp. (Delaware)
  • Defendant: Ameren Corporation (Missouri) and Union Electric Co. (d/b/a Ameren Missouri) (Missouri)
  • Plaintiff’s Counsel: The Simon Law Firm, P.C. and Caldwell Cassady & Curry P.C.
• Case Identification: 4:24-cv-00980, E.D. Mo., 07/17/2024
• Venue Allegations: Venue is alleged to be proper as Defendants reside in the district and operate the accused coal-fired power plants within the district, constituting a regular and established place of business where acts of infringement occur.
• Core Dispute: Plaintiff alleges that Defendants' operation of three coal-fired power plants infringes five patents related to methods for removing mercury from flue gas.
• Technical Context: The technology addresses methods for controlling mercury pollution from industrial combustion processes, a field driven by environmental regulations such as the U.S. Environmental Protection Agency's Mercury and Air Toxics Standards (MATS).
• Key Procedural History: The complaint references a prior lawsuit filed by Plaintiff in July 2019 in the District of Delaware against other entities. On March 1, 2024, a jury in that case found two of the patents-in-suit ('114 and '517) were willfully infringed. The complaint also alleges that Plaintiff contacted Defendants on February 5, 2021, to negotiate a license and that Defendant Union Electric was served with a subpoena in connection with the Delaware litigation in August 2021.

Case Timeline

Date	Event
2004-08-30	Earliest Priority Date for all Patents-in-Suit
2019-07-09	U.S. Patent No. 10,343,114 Issues
2019-07	Plaintiff files related litigation in the District of Delaware
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
2021-02-05	Plaintiff contacts Defendants to negotiate a license
2021-03-02	U.S. Patent No. 10,933,370 Issues
2021-08	Plaintiff serves subpoena on Defendant Union Electric
2024-03-01	Jury verdict of willful infringement in related Delaware litigation
2024-07-17	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, entitled “Sorbents for the Oxidation and Removal of Mercury,” issued July 9, 2019 (the “'114 Patent”).

The Invention Explained

• Problem Addressed: The patent describes a technical challenge in removing mercury, particularly elemental mercury, from the flue gas of coal combustion facilities. Existing methods, such as injecting activated carbon, were noted to be relatively unreactive, requiring large quantities of expensive sorbent and creating solid waste disposal problems. (’114 Patent, col. 2:11-20).
• The Patented Solution: The invention proposes a method where a base sorbent, such as activated carbon, is treated with a halogen or halide "promoter" (e.g., bromine). This process creates a "promoted sorbent" with highly reactive chemical sites on its surface that can more efficiently oxidize elemental mercury and capture it from the gas stream, even with short contact times. (’114 Patent, Abstract; col. 3:37-51).
• Technical Importance: This approach aimed to increase the efficiency and reduce the cost of mercury emission control, a critical objective for power plants needing to comply with federal environmental standards finalized in 2011. (Compl. ¶¶ 22, 24).

Key Claims at a Glance

• The complaint asserts independent claim 25 and reserves the right to assert claims 1-30. (Compl. ¶¶ 74, 76).
• The essential elements of independent 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 or the combustion chamber comprises an added promoter such as Br2, HBr, or a bromide compound.
  • Injecting a sorbent material comprising activated carbon into the mercury-containing gas downstream of the combustion chamber.
  • Contacting 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.

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

• Patent Identification: U.S. Patent No. 10,596,517, entitled “Sorbents for the Oxidation and Removal of Mercury,” issued March 24, 2020 (the “’517 Patent”).

The Invention Explained

• Problem Addressed: As with the related ’114 Patent, the background addresses the inefficiency of prior art methods for removing mercury from flue gas streams, which required large amounts of sorbent and had limited effectiveness against elemental mercury. (’517 Patent, col. 2:11-20).
• The Patented Solution: The invention discloses a method of treating coal with a halogen/halide additive before or during combustion. This pre-treatment is described as creating a flue gas in which mercury is more readily captured by a downstream sorbent, such as activated carbon. (’517 Patent, Abstract; col. 3:9-21).
• Technical Importance: The technology provided an alternative means of enhancing mercury capture, potentially simplifying the process by treating the fuel source directly rather than preparing a separate promoted sorbent for injection. (Compl. ¶22).

Key Claims at a Glance

• The complaint asserts independent claim 1 and reserves the right to assert claims 1-30. (Compl. ¶¶ 94, 96).
• The essential elements of independent claim 1 are:
  • A method for reducing mercury in a mercury-containing gas.
  • Combusting coal in a combustion chamber, where the coal comprises an additive such as Br2, HBr, or a bromide compound, to form the mercury-containing gas.
  • Collecting mercury from the gas with a sorbent comprising activated carbon that is added to the gas.

Multi-Patent Capsule: U.S. Patent No. 10,589,225

• Patent Identification: U.S. Patent No. 10,589,225, "Sorbents for the Oxidation and Removal of Mercury," issued March 17, 2020 (the “'225 Patent”). (Compl. ¶9).
• Technology Synopsis: The patent describes a method for treating mercury-containing gas by combusting a mixture that includes not only coal but also pyrolysis char, along with a bromine-based additive. Following combustion, a particulate sorbent comprising activated carbon is added to the gas to capture mercury. (Compl. ¶¶ 112, 114, 116).
• Asserted Claims: The complaint provides an explanation of infringement with regard to exemplary claim 1 and asserts infringement of at least one of claims 1-29. (Compl. ¶¶ 110-111).
• Accused Features: The complaint alleges that Defendants' power plants perform the patented method by combusting coal, pyrolysis char, and a bromine-based additive, and then adding activated carbon sorbent to the resulting flue gas. (Compl. ¶¶ 115, 117).

Multi-Patent Capsule: U.S. Patent No. 10,668,430

• Patent Identification: U.S. Patent No. 10,668,430, "Sorbents for the Oxidation and Removal of Mercury," issued June 2, 2020 (the “'430 Patent”). (Compl. ¶11).
• Technology Synopsis: This patent claims a method of separating mercury from gas that involves combusting coal with a bromine-based additive, where the additive is added either to the coal before it enters the combustion chamber or directly into the chamber. The method proceeds by injecting an activated carbon sorbent downstream, contacting the mercury, and separating the resulting composition. (Compl. ¶¶ 128, 130, 132).
• Asserted Claims: The complaint provides an explanation of infringement with regard to exemplary claim 1 and asserts infringement of at least one of claims 1-29. (Compl. ¶¶ 126-127).
• Accused Features: The complaint alleges Defendants' plants infringe by combusting coal with a bromine additive, injecting activated carbon downstream, and collecting the mercury-laden sorbent. (Compl. ¶¶ 131, 133, 137).

Multi-Patent Capsule: U.S. Patent No. 10,933,370

• Patent Identification: U.S. Patent No. 10,933,370, "Sorbents for the Oxidation and Removal of Mercury," issued March 2, 2021 (the “'370 Patent”). (Compl. ¶12).
• Technology Synopsis: This patent claims a method for separating mercury from gas that specifies a particular ratio between the amount of additive (e.g., halides, halogens) used in combustion and the amount of activated carbon sorbent added downstream. The claimed weight ratio of additive to sorbent is from about 1:100 to about 30:100. (Compl. ¶152).
• Asserted Claims: The complaint provides an explanation of infringement with regard to exemplary claim 1 and asserts infringement of at least one of claims 1-29. (Compl. ¶¶ 146-147).
• Accused Features: The complaint alleges that Defendants' plants perform the claimed method by using additives and sorbents that fall within the specified weight ratios. (Compl. ¶¶ 151, 153).

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are the processes and methods used in the operation of Defendants' coal-fired power plants, identified as the Labadie Energy Center, the Rush Island Energy Center, and the Sioux Energy Center (the "Accused Coal Plants"). (Compl. ¶¶ 42, 52).

Functionality and Market Context

• The complaint alleges the Accused Coal Plants perform a multi-step process for mercury emission control. This process involves (1) combusting coal that contains an added bromine-based compound to generate flue gas containing mercury; (2) injecting an activated carbon sorbent into the flue gas after it leaves the combustion chamber; and (3) using particulate collection equipment, such as baghouses or electrostatic precipitators (ESPs), to capture the sorbent material, which has become bound to mercury. (Compl. ¶¶ 43-51). These actions are allegedly performed to comply with federal and/or state mercury regulations. (Compl. ¶77). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

’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.	The Accused Coal Plants are alleged to perform this method to comply with mercury regulations.	¶77	col. 5:36-40
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...	The Accused Coal Plants allegedly burn coal with an added bromine-based compound and/or add such a compound directly to the combustion chamber.	¶79	col. 3:10-21
injecting a sorbent material comprising activated carbon into the mercury containing gas downstream of the combustion chamber.	The Accused Coal Plants allegedly inject activated carbon sorbent downstream of the combustion chamber.	¶81	col. 5:46-50
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.	¶83	col. 10:1-6
separating the mercury/sorbent composition from the mercury-containing gas, to form a cleaned gas.	The Accused Coal Plants allegedly use equipment such as baghouses or electrostatic precipitators to collect the mercury captured by the sorbent.	¶85	col. 13:35-44

’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.	The Accused Coal Plants are alleged to perform this method to comply with mercury regulations.	¶97	col. 5:36-40
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.	The Accused Coal Plants allegedly combust coal with an additive comprising Br2, HBr, a bromide compound, or a combination thereof.	¶99	col. 3:9-21
collecting mercury in the mercury-containing gas with a sorbent added to the mercury-containing gas, the sorbent comprising activated carbon.	The Accused Coal Plants allegedly add an activated carbon sorbent to the flue gas and then collect the mercury using equipment such as baghouses or electrostatic precipitators.	¶101	col. 2:62-67

Identified Points of Contention

• Scope Questions: A central question may be whether the specific chemical "additives" allegedly used by Defendants fall within the scope of the claimed terms, such as "additive comprising Br2, HBr, a bromide compound, or a combination thereof." While the complaint makes a direct allegation, the precise chemical identity and function of the materials used by Defendants will be a subject of discovery.
• Technical Questions: For the ’370 Patent, a key factual question will be whether the weight ratio of the additive to the sorbent used in the Accused Coal Plants falls within the claimed range of "from about 1:100 to about 30:100." The complaint alleges this is met, but provides no specific data to support the allegation. (Compl. ¶153).

V. Key Claim Terms for Construction

• The Term: "additive comprising Br2, HBr, a bromide compound, or a combination thereof" (’114 Patent, Claim 25; ’517 Patent, Claim 1)

• Context and Importance: This term defines the chemical agent that initiates the patented process. The scope of infringement hinges on which chemical substances qualify as this "additive." Practitioners may focus on this term because the specific composition used by Defendants could be argued to fall outside a narrow construction.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification describes the "promoter" broadly as being selected from "halides, halogens, and combinations thereof" and provides numerous examples, suggesting the claim term should not be limited to only the three species explicitly recited. (’114 Patent, col. 3:10-14).
  • Evidence for a Narrower Interpretation: The specification provides a detailed chemical theory for how bromide and bromine species create reactive sites on the sorbent. (’114 Patent, FIG. 2; col. 12:5-24). A defendant may argue that the term "additive" should be limited to compounds that function according to this specific mechanism, potentially excluding other bromine-containing substances that operate differently.

• 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 relative to the combustion process. Infringement requires the injection to occur at a specific point in the flue gas path, making the definition of the "combustion chamber" boundary critical.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The patent’s description and figures illustrate injection into the flue gas duct after the boiler, suggesting "downstream" refers to any point after the primary zone of fuel combustion. (’114 Patent, FIG. 6; col. 5:46-50).
  • Evidence for a Narrower Interpretation: The specification describes the process as occurring in "downstream process sections, such as in the ducts and stack of a combustion system." (’114 Patent, col. 1:40-42). A defendant might argue this language implies a location physically distinct and separate from the boiler structure itself, potentially creating a non-infringement argument if their injection point is in an area considered an integral part of the boiler outlet.

VI. Other Allegations

• Indirect Infringement: The complaint alleges that parent company Ameren induces its subsidiary Union Electric to infringe. The alleged acts of inducement include Ameren's awareness of the patents, its participation in supply contract processes for the accused materials (activated carbon and bromine additives), and its exercise of control over Union Electric's operations. (Compl. ¶¶ 55-57, 87, 103).
• Willful Infringement: The willfulness allegation is based on alleged pre-suit knowledge of the patents. The complaint cites a February 5, 2021 communication from Plaintiff to Defendants regarding licensing the ’114 Patent, as well as a subpoena served on Union Electric in August 2021 in connection with separate litigation on the same family of patents. (Compl. ¶¶ 62, 64). The complaint further points to a jury verdict of willfulness against other parties for infringement of the ’114 and ’517 patents as evidence that Defendants knew or should have known their actions constituted infringement. (Compl. ¶41, ¶67).

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

• A core issue will be one of evidentiary proof: can Plaintiff produce evidence from discovery demonstrating that the specific chemical processes and materials used at Defendants' three power plants meet each limitation of the asserted claims? This will be particularly crucial for the '370 Patent, which requires proof that the weight ratio of additive to sorbent falls within a specific numerical range.
• A key legal question will be one of willfulness: can Plaintiff establish that Defendants acted with the requisite state of mind for willful infringement, given the allegations of direct notice in 2021 and their awareness of parallel litigation involving the same patents that resulted in a willfulness verdict against other industry participants? The court will need to determine when Defendants' knowledge rose to the level of "wanton and malicious" conduct, if at all.