DCT

3:24-cv-00033

Topsoe Inc v. Casale US Inc

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Amended Complaint
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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 3:24-cv-00033, S.D. Tex., 08/20/2026
  • Venue Allegations: Plaintiff alleges venue is proper because Defendant committed acts of false advertising and attempted to enforce its patent in the district, and because Defendant is not a resident of the United States, it may be sued in any judicial district.
  • Core Dispute: Plaintiff Topsoe seeks a declaratory judgment that Defendant Casale's patent for low-carbon ammonia production is unenforceable due to fraudulent procurement, and further alleges that Casale's enforcement activities constitute illegal monopolization under the Sherman Act.
  • Technical Context: The lawsuit concerns technology for "blue ammonia" production, a process critical for reducing carbon emissions in the fertilizer and chemical industries by capturing carbon dioxide generated during manufacturing.
  • Key Procedural History: This Fourth Amended Complaint follows significant post-issuance proceedings for the patent-in-suit. Casale initiated a supplemental examination which led the U.S. Patent and Trademark Office (PTO) to order an ex parte reexamination and subsequently cancel all original claims, issuing a certificate with narrowed claims in July 2024. In response to Casale's infringement counterclaims based on the reexamined patent, Topsoe filed petitions for inter partes review (IPR), one of which was instituted in February 2026 based on a finding of "substantial questions of patentability."

Case Timeline

Date Event
1988-05-01 First Topsoe-designed IFFCO plant unit commissioned in India
1996-12-01 Second Topsoe-designed IFFCO plant unit commissioned in India
2009-01-01 Topsoe describes "split-for-fuel" process at FAI Seminar in India
2014-01-01 Casale begins revamp project on Topsoe's IFFCO plant
2017-02-15 '168 Patent earliest priority date
2018-01-01 Casale completes revamp project on Topsoe's IFFCO plant
2018-01-31 '168 Patent effective filing date
2019-08-13 Casale files application for the '168 Patent
2022-03-29 U.S. Patent No. 11,286,168 ('168 Patent) issues
2022-11-09 Casale sends letter to Topsoe customer alleging potential infringement
2023-02-16 Casale requests supplemental examination of the '168 Patent
2023-06-28 PTO orders ex parte reexamination of the '168 Patent
2024-07-16 PTO issues reexamination certificate for the '168 Patent with narrowed claims
2025-08-22 Topsoe files IPR petitions against the reexamined '168 Patent
2025-12-09 Casale files patent infringement counterclaims against Topsoe
2026-02-10 PTO institutes IPR against the reexamined '168 Patent
2026-08-20 Topsoe files Fourth Amended Complaint

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

U.S. Patent No. 11,286,168 - "PROCESS FOR THE SYNTHESIS OF AMMONIA WITH LOW EMISSIONS OF CO2 IN ATMOSPHERE"

  • Issued: March 29, 2022

The Invention Explained

  • Problem Addressed: The patent's background describes that conventional ammonia synthesis plants result in significant carbon dioxide (CO2) emissions, and prior art methods for capturing CO2 from flue gases are costly, complex, and energy-intensive '168 Patent, col. 1:40-62
  • The Patented Solution: The invention proposes a method to reduce CO2 emissions by altering the fuel source within the ammonia plant. After natural gas is converted to a synthesis gas and most of the CO2 is removed, the resulting hydrogen-rich, CO2-depleted gas is split into two streams. One stream, the "fuel fraction," is routed to a furnace and burned as fuel. The second stream, the "process fraction," continues on to be converted into ammonia. Because the fuel fraction consists mainly of hydrogen, its combustion produces little to no CO2, thereby lowering the plant's overall emissions '168 Patent, abstract '168 Patent, col. 2:29-47
  • Technical Importance: This "split-for-fuel" technique provides a pathway to achieve high levels of carbon capture (e.g., "blue ammonia") more economically than methods requiring expensive post-combustion CO2 scrubbing technology Compl. ¶130

Key Claims at a Glance

The complaint primarily contests the enforceability of the original claims of the '168 Patent, which were procured before being cancelled and replaced by narrowed claims in a reexamination proceeding Compl. ¶¶103-107 Compl. ¶338 Original independent claims 1 and 21 are central to the allegations of fraudulent procurement Compl. ¶¶357-359

  • Original Independent Claim 1 (Process Claim):

    • Converting desulphurized natural gas and steam into a synthesis gas.
    • Treating the synthesis gas to remove CO2, obtaining a "CO2-depleted synthesis gas."
    • Separating a part of the CO2-depleted synthesis gas as a "fuel fraction" and feeding it as fuel to a furnace.
    • Wherein the separation includes splitting the CO2-depleted gas into a first stream (the fuel fraction) and a second stream (the process gas for ammonia synthesis).
    • Crucially, the claim requires that "said first and second streams having the same composition" '168 Patent, original claim 1 Compl. ¶357

  • The complaint does not specify an intent to assert particular dependent claims but notes that original claims 1-23 were found to have a substantial new question of patentability Compl. ¶102

III. The Accused Instrumentality

Product Identification

  • The complaint centers on Casale's allegations that Topsoe's SynCOR Ammonia™ process infringes the '168 Patent Compl. ¶90

Functionality and Market Context

  • The complaint describes the SynCOR™ process as a single-step autothermal reforming (ATR) technology used to produce low-carbon or "blue" ammonia Compl. ¶131
  • A key feature highlighted is its use of a "split-for-fuel" configuration, where a portion of CO2-depleted synthesis gas is used as fuel for the plant's heater. This feature is alleged to enable the process to achieve approximately 99.3% carbon capture without needing a separate, costly post-combustion capture unit Compl. ¶131 The complaint includes a diagram of the SynCOR™ process, which Casale allegedly used to assert infringement, showing a "H2 Fuel" stream being separated and routed to a fired heater Compl. ¶92
  • Topsoe alleges its SynCOR™ technology is a market leader, representing about 90% of the nascent U.S. market for blue ammonia licenses due to its superior, industrially-proven performance at scale Compl. ¶10

IV. Analysis of Infringement Allegations

The infringement allegations are not made by the Plaintiff but are Defendant Casale's assertions as described in the complaint. Topsoe recounts that Casale claimed infringement was "self-evident" based on a public diagram of the SynCOR™ process Compl. ¶¶92-93 The following chart summarizes Casale's alleged infringement theory against Topsoe's SynCOR™ process, mapping it to the elements of original claim 1 of the '168 Patent.

'168 Patent Infringement Allegations

Claim Element (from Original Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A process for synthesis of ammonia from natural gas, the process comprising: conversion of a charge of desulphurized natural gas and steam... into a synthesis gas... in a conversion section; The SynCOR™ process is used for ammonia synthesis and involves converting natural gas into synthesis gas using an autothermal reformer (ATR). ¶131; ¶92 col. 7:18-22
treatment of said synthesis gas including at least a shift reaction... and subsequent separation of CO2 from the gas, thus obtaining a CO2-depleted synthesis gas...; The SynCOR™ process diagram shows steps for "CO shift conversion" and "CO2 removal" following the reforming step, which produces a CO2-depleted gas. ¶92 col. 7:22-29
separation of a part of said CO2-depleted synthesis gas as fuel fraction, wherein said fuel fraction is fed as fuel to at least one furnace... The complaint states the SynCOR™ process is "configured with split-for-fuel-using part of the CO2-depleted synthesis gas as heater fuel." The process diagram shows a "H2 Fuel" stream being fed to a "Fired heater." ¶92; ¶131 col. 8:25-29
wherein said separation of the fuel fraction includes the split of said CO2-depleted synthesis gas into at least a first stream and a second stream, said first and second streams having the same composition... Topsoe alleges that its process has long included "splitting a CO2-depleted synthesis gas stream into two streams of the same composition," the very feature Casale argued to the PTO was its distinguishing invention. ¶49; ¶56; ¶58 col. 3:5-9
  • Identified Points of Contention:
    • Validity and Enforceability: The primary point of contention identified in the complaint is not a technical mismatch regarding infringement, but the validity and enforceability of the '168 Patent itself. Topsoe alleges that the key "split-for-fuel" concept with "same composition" streams-the feature Casale relied on to secure the patent-was taught by multiple prior art references that Casale knowingly and intentionally withheld from the PTO, constituting inequitable conduct (Compl. ¶251; Compl. ¶252; Compl. ¶253; Compl. ¶254). This is supported by a diagram in the complaint from a 2009 Topsoe presentation allegedly showing the same concept of recycling excess syngas as fuel Compl. ¶365
    • Scope Questions (Reexamined Claims): For Casale's infringement counterclaims on the reexamined patent, a potential dispute may arise over the new limitation added to claim 1, which now requires a "conversion section including an autothermal reformer downstream from a pre-reformer and without a primary reformer therebetween" Reexam. Cert., col. 2:1-5 The question will be whether Topsoe's SynCOR™ process, described as a "single-step ATR process" that sometimes follows a "pre-reformer," meets this more specific structural requirement Compl. ¶92 Compl. ¶131

V. Key Claim Terms for Construction

  • The Term: "first and second streams having the same composition"
  • Context and Importance: This phrase was the "distinguishing feature" Casale successfully argued to the PTO to overcome an obviousness rejection during the original prosecution Compl. ¶58 Compl. ¶361 Topsoe's central allegation of inequitable conduct rests on the assertion that its own prior art, which it alleges Casale knew of and concealed, taught this exact feature Compl. ¶254 The construction of this term is therefore critical to both the historical question of patentability and any ongoing infringement analysis.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent specification describes the separation as "splitting a process flow," which inherently suggests that the resulting streams are identical at the point of division '168 Patent, col. 3:5-9 Practitioners may argue this supports a plain and ordinary meaning of "same composition" as being chemically identical or substantially identical.
    • Evidence for a Narrower Interpretation: During prosecution, Casale distinguished its invention from prior art that created a "hydrogen rich stream and a methane rich stream" Compl. ¶361 A party might argue that "same composition" should be construed narrowly in light of this distinction, though the primary contrast appears to be between splitting a single source stream versus generating two chemically different streams. The patent itself does not appear to offer a basis for a narrower definition beyond this contrast.

VI. Other Allegations

  • Indirect Infringement: The complaint states that Casale asserted claims for indirect infringement in its December 9, 2025 counterclaims Compl. ¶118 However, the complaint does not provide sufficient detail for analysis of the specific facts alleged by Casale to support induced or contributory infringement.
  • Willful Infringement: The complaint does not allege willfulness by Topsoe, but rather alleges that Casale's enforcement of the '168 Patent was undertaken in bad faith, which is the basis for Topsoe's antitrust and unfair competition claims. The complaint alleges Casale had pre-suit knowledge of the patent's invalidity from its access to Topsoe's technology at the IFFCO plant revamp Compl. ¶¶48-49, its awareness of Topsoe's 2009 publications Compl. ¶51 Compl. ¶253, and its knowledge of other prior art Compl. ¶¶369-382 It further alleges that Casale continued to assert the patent post-suit despite the PTO cancelling the original claims and instituting an IPR on the reexamined claims Compl. ¶114 Compl. ¶117 A diagram from a 2010 prior art presentation by Uhde von Trotha is included as an example of prior art Casale allegedly knew of and withheld, which also shows a "CO2-free firing" concept Compl. p. 127

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

  • A central issue for the court will be one of fraudulent procurement: did Casale, its inventors, and its attorneys intentionally deceive the USPTO by withholding material prior art-specifically Topsoe's own commercial processes and publications-that taught the key "same composition split-for-fuel" feature, and if so, does this inequitable conduct render the reexamined '168 Patent unenforceable?

  • A key economic and legal question will be one of market definition and monopolization: does Casale's enforcement of the allegedly fraudulent '168 Patent constitute an illegal attempt to monopolize the "high-capture" and "ultra-high-capture" blue ammonia technology markets, and are these narrowly-defined, performance-based product markets legally cognizable for antitrust analysis?

  • For Casale's infringement counterclaims, a key evidentiary question will be one of infringement under the reexamined claims: does Topsoe's SynCOR™ process, which utilizes a pre-reformer and an autothermal reformer, meet the specific structural limitations of the newly-added language in reexamined claim 1, which now requires a conversion section "without a primary reformer therebetween"?

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