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Control of VOCs by Incineration
Published in Howard E. Hesketh, Frank L. Cross, Sizing and Selecting Air Pollution Control Systems, 2020
Regenerative thermal oxidizer: This system utilizes oxidized gases from the combustion chamber by passing it through millions of inert ceramic elements contained in a porous heat transfer section. A system of valves is used to control the inlet of contaminated air into the heat transfer section where the fumes are preheated by convection of the stored heat to within 5% of oxidation temperature on their way to the combustion chamber (up to 95% of the heat of combustion is stored by conduction in the ceramic elements). An uninterrupted flow of VOC-laden gas is processed through the system at all times. This flow is provided for the system by a continuous cycle of alternately storing and releasing heat within three heat transfer sections.
Air Stripping and Soil Vapor Extraction as Site Remediation Measures
Published in Donald L. Wise, Debra J. Trantolo, Edward J. Cichon, Hilary I. Inyang, Ulrich Stottmeister, Remediation Engineering of Contaminated Soils, 2000
Constantine J. Gregory, Frederic C. Blanc
Thermal oxidation is an effective treatment for vapor steams with high levels of combustible contaminants. The contaminant levels in the vapor stream generally decline with time, thereby requiring an increase in amounts of auxiliary fuel required for maintaining proper combustion. Incorporation of a thermal oxidizer for off-gas treatment may dictate the overall operating characteristics of a soil vapor extraction system. Effective operation of a thermal oxidizer, i.e., maximum efficiency of contaminant destruction, will be a function of flame temperature and gas flow rate. Hence, attainment of maximum efficiency determines the operating vacuum applied to extraction wells. When chlorinated
VOC Destruction Efficiency
Published in David A. Lewandowski, Design of Thermal Oxidation Systems for Volatile Organic Compounds, 2017
In selecting the design and operating conditions for a thermal oxidizer, the destruction efficiency requirements must be clearly stated. When more than one volatile organic compound is present in the waste gas, does the destruction efficiency requirement apply to each individual organic component or to the group as an aggregate?
Developing innovative treatment technologies for PFAS-containing wastes
Published in Journal of the Air & Waste Management Association, 2022
Chelsea Berg, Brian Crone, Brian Gullett, Mark Higuchi, Max J. Krause, Paul M. Lemieux, Todd Martin, Erin P. Shields, Ed Struble, Eben Thoma, Andrew Whitehill
Pyrolysis decomposes solid or semi-solid materials at temperatures typically in the 300°C to 1000°C range in an oxygen-free environment. Gasification is similar to pyrolysis but operates at temperatures typically in the 800°C to 1650°C range with substoichiometric quantities of oxygen in a partial combustion process to provide additional energy to the process (Fytili and Zabaniotou 2008; Patel et al. 2020; Winchell et al. 2020). Pyrolysis can form a useful char (Boni et al. 2021) product whereas gasification typically forms low carbon ash. Both processes can generate a hydrogen-rich synthetic gas (syngas) depending on operating conditions. The high temperatures and residence times achieved by the combination of pyrolysis or gasification, followed directly by combustion of the hydrogen-rich syngas stream in a thermal oxidizer could potentially destroy PFAS by breaking apart the chemicals into inert or less recalcitrant constituents, although this remains a subject for further research. Compared to traditional incineration, pyrolysis and gasification require much lower air flows than incineration, which reduces the size and capital expense of air pollution control equipment. More information is available in the U.S. EPA’s Research Brief on Pyrolysis and Gasification of Biosolids (Acheson et al. 2021).
Characterization of PFAS air emissions from thermal application of fluoropolymer dispersions on fabrics
Published in Journal of the Air & Waste Management Association, 2023
Lindsay C. Wickersham, James M. Mattila, Jonathan D. Krug, Stephen R. Jackson, M. Ariel Geer Wallace, Erin P. Shields, Hannah Halliday, Emily Y. Li, Hannah K. Liberatore, Stanley (Mac) Farrior, William Preston, Jeffrey V. Ryan, Chun-Wai Lee, William P. Linak
Results indicate that commercially relevant fabric-coating operating conditions are fully able to alter PFAS compositions and produce a variety of thermal decomposition products that would be released as air emissions unless a thermal oxidizer or another type of air pollution control device were installed. In the absence of such emission treatment technologies, it is possible that these PFAS thermal byproducts, as well as others not yet identified, could impact air quality and environmental and human health.