PTAB

IPR2025-00718

PacifiCorp v. MES Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Mercury Separation from Gas
  • Brief Description: The ’218 patent discloses methods for removing mercury from mercury-containing gas, such as flue gas from coal combustion. The methods involve adding an iodine-containing compound (hydrogen iodide or an iodide salt) to the coal or combustion chamber, and subsequently injecting an activated carbon sorbent downstream to contact and separate the mercury.

3. Grounds for Unpatentability

Petitioner first argued that the ’218 patent is not entitled to priority before April 2018, because earlier applications in the priority chain allegedly lack written description support for adding iodine-based compounds directly to the coal or combustion chamber. This lack of priority renders the asserted references, including Baldrey (2011), Sjostrom (2005), Olson-646 (2006), and Olson-235 (2014), valid prior art.

Ground 1: Claims 1-4, 6-9, 13-17, and 20-25 are anticipated by Baldrey

  • Prior Art Relied Upon: Baldrey (Application # 2011/0030592).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Baldrey discloses every limitation of the challenged claims. Baldrey teaches a method for mercury removal from flue gas by adding a halogen-containing additive, specifically including "halide salts" like "potassium iodide," to the coal feed before it enters the combustion chamber. It further discloses injecting an activated carbon sorbent downstream of the furnace to capture the mercury, which is then separated by a particulate removal device. Petitioner argued that Baldrey also explicitly discloses concentration ranges for both the additive and the sorbent that result in a weight ratio falling within the claimed 1:100 to 30:100 range.

Ground 2/3: Claims 1-4 and 6-26 are obvious over Baldrey in view of Olson-235 or Olson-646

  • Prior Art Relied Upon: Baldrey (Application # 2011/0030592), Olson-235 (Patent 8,652,235), and Olson-646 (Application # 2006/0048646).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Baldrey teaches the core process of adding a halide to coal and injecting a sorbent downstream. The Olson references, which describe promoting activated carbon with iodine-containing materials, explicitly disclose the claimed weight ratio limitation of "from about 1 to about 30 grams [of promoter] per 100 grams of activated carbon." This ratio is absent in Baldrey but is a key element of several claims. The combination also teaches adding an alkaline material like calcium oxide (claim 19) and using feedback control based on continuous mercury monitoring to adjust injection rates (claims 10-12).
    • Motivation to Combine: A POSITA would combine Baldrey’s general process with the specific, workable ratios taught in Olson to optimize mercury removal. Olson provides the precise implementation details and conventional ranges for the halide:sorbent ratio that a POSITA would naturally seek when applying Baldrey’s teachings.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination involves applying known optimization parameters (the ratios from Olson) to a known mercury capture system (the process from Baldrey) to achieve the predictable result of effective mercury removal.

Ground 4/5: Claims 1-4 and 6-26 are obvious over Sjostrom in view of Olson-235 or Olson-646

  • Prior Art Relied Upon: Sjostrom (a 2005 conference presentation), Olson-235 (Patent 8,652,235), and Olson-646 (Application # 2006/0048646).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Sjostrom teaches the fundamental process, showing a diagram with options for adding halogens (Cl, Br, F, I) as "coal additives" before the boiler (Location 1), directly into the combustion chamber (Location 2), or to the sorbent downstream (Location 3). Sjostrom further discloses injecting activated carbon sorbent downstream. While Sjostrom generically discloses adding "I" (iodine), the Olson references specify using effective iodine promoters like HI and iodide salts and disclose the claimed 1:100 to 30:100 weight ratio.
    • Motivation to Combine: A POSITA implementing Sjostrom’s system would have been motivated to consult references like Olson to select a specific, effective chemical form for the generically disclosed iodine and to determine workable quantities. Olson provides this by identifying HI and iodide salts as effective and teaching the specific ratios for their use, representing a simple and logical substitution to optimize Sjostrom’s process.
    • Expectation of Success: The combination represents the application of a known technique (halide promotion with specific iodides from Olson) to a known system (Sjostrom's mercury capture process) to yield predictable results, such as achieving over 70% mercury removal as taught by both references.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on the Sjostrom/Olson combinations further in view of Olson-279, which bridges the references by teaching that a "pre-added promoter" like ammonium iodide (an iodide salt) can be added to coal to generate HI in the flue gas.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-4 and 6-26 of Patent 10,926,218 as unpatentable.