Sorbents For The Oxidation And Removal Of Mercury
Patent No. US10933370 (titled "Sorbents For The Oxidation And Removal Of Mercury") was filed by Birchtech Corp on Apr 12, 2018.
What is this patent about?
’370 is related to the field of mercury removal from flue gas streams , particularly those generated by coal combustion. The background involves the need to control mercury emissions from power plants and other industrial facilities that burn fossil fuels. Existing methods, such as injecting activated carbon into the flue gas, have limitations in terms of efficiency, cost, and waste disposal.
The underlying idea behind ’370 is to enhance the reactivity of activated carbon sorbents by modifying them with halogens or halides , creating a more effective material for capturing mercury. This modification involves forming a reactive compound on the carbon surface that promotes the oxidation and subsequent capture of mercury from the gas stream. The key insight is that the halogen/halide treatment creates a carbon structure with a high chemical potential for oxidizing mercury.
The claims of ’370 focus on a method for separating mercury from a mercury-containing gas, which involves combusting coal with a halogen-containing additive, adding a particulate sorbent material comprising activated carbon into the mercury-containing gas, contacting mercury in the mercury-containing gas with the sorbent material, to form a mercury-sorbent, and separating the mercury-sorbent from the mercury-containing gas. The ratio of additive to sorbent is specified as being from about 1:100 to about 30:100.
In practice, the invention involves introducing a halogen or halide, such as bromine, into the activated carbon structure. This can be done through gas-phase or liquid-phase reactions. The resulting modified carbon sorbent is then injected into the flue gas stream, where it captures mercury through a combination of oxidation and adsorption. The spent sorbent, along with the captured mercury, is then separated from the flue gas using conventional particulate control devices like baghouses or electrostatic precipitators.
The invention differentiates itself from prior approaches by creating a highly reactive sorbent that doesn't require an induction period and can be used in smaller amounts. Unlike some prior art that simply mixes halogens with the gas stream, this invention chemically modifies the carbon structure to enhance its mercury capture capabilities. Furthermore, the patent describes methods for regenerating the sorbent and separating it from ash, enabling reuse and reducing waste disposal issues. The use of larger particle sizes also facilitates separation from fly ash.
How does this patent fit in bigger picture?
Technical landscape at the time
In the mid-2000s when ’370 was filed, mercury removal from flue gas was typically implemented using sorbent injection systems. At a time when systems commonly relied on activated carbon, the effectiveness of these systems was limited by the slow reaction kinetics of the sorbent, especially for elemental mercury. When hardware or software constraints made sorbent regeneration and reuse non-trivial, disposal of mercury-laden sorbents posed environmental and economic challenges.
Novelty and Inventive Step
The examiner agreed with the applicant's description of how the amended claims are different from what's already known. The existing solutions don't show or suggest using a specific weight ratio of an additive (halides, halogens, or salts) added to the coal and/or combustion chamber, relative to the amount of sorbent injected, along with the other steps in the claimed process.
Claims
This patent contains 18 claims, with independent claims 1 and 17 directed to methods for separating mercury from a mercury-containing gas using a combination of additives and sorbent materials during coal combustion. The dependent claims generally specify details and variations of the method described in independent claim 1, such as specific additives, sorbent materials, and additional process steps.
Key Claim Terms New
Definitions of key terms used in the patent claims.
Litigation Cases New
US Latest litigation cases involving this patent.
Patent Family
File Wrapper
The dossier documents provide a comprehensive record of the patent's prosecution history - including filings, correspondence, and decisions made by patent offices - and are crucial for understanding the patent's legal journey and any challenges it may have faced during examination.
Date
Description
Get instant alerts for new documents
US10933370
- Application Number
- US15951970
- Filing Date
- Apr 12, 2018
- Status
- Granted
- Expiry Date
- Apr 24, 2026
- External Links
- Slate, USPTO, Google Patents