Dynamic flux chamber measurements of hydrogen sulfide emission rate from a quiescent surface – A computational evaluation

Dynamic flux chamber measurements of hydrogen sulfide emission rate from a quiescent surface – A computational evaluation

Enclosure devices have been studied and used for research purposes and practical applications in order to measure the emission rate of odorous pollutants from quiescent liquid surfaces to atmosphere. However, important questions remain about the interference of these measuring devices on the actual...

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Bibliographic Details
Published in:Chemosphere (Oxford) Vol. 146; pp. 426 - 434
Main Authors: Prata, Ademir A., Santos, Jane M., Beghi, Sandra P., Fernandes, Isabella F., Vom Marttens, Lya L.C., Pereira Neto, Leovegildo I., Martins, Ramon S., Reis, Neyval C., Stuetz, Richard M.
Format: Journal Article
Language:English
Published: England Elsevier Ltd 01-03-2016
Elsevier
Subjects:
Air Pollutants - analysis
Area sources
Chambers
Computational fluid dynamics
Computer Simulation
Dynamic flux chamber
Emission
Emission analysis
Engineering Sciences
Environmental Monitoring - instrumentation
Equipment Design
Flux
Hydrogen sulfide
Hydrogen Sulfide - analysis
Mathematical models
Odorants - analysis
Odour emission
Surface Properties
United States
Walls
Waste Water - chemistry
USA
Dynamic flux chamber
Area sources
Odour emission
Computational fluid dynamics
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Summary:Enclosure devices have been studied and used for research purposes and practical applications in order to measure the emission rate of odorous pollutants from quiescent liquid surfaces to atmosphere. However, important questions remain about the interference of these measuring devices on the actual emission rate. The main concern regarding the use of a flux chamber is the fact that odorous compounds can accumulate into the chamber and yield gas-phase concentration increase inside the equipment, which causes a reduction of the emission rate during the measurement and thus gives an inaccurate local emission rate. Furthermore, the fluid flow inside the chamber does not reproduce the atmospheric boundary layer flow. This study applied the Computational Fluid Dynamics (CFD) technique in order to investigate the influence of the fluid flow features inside a flux chamber on the measured hydrogen sulfide emission rate at quiescent liquid surfaces. The flux chamber design and operational conditions are those supported by the United States Environmental Protection Agency (US EPA). The results show that the US EPA flux chamber presents a fairly well mixed air phase. However, a trend to stagnation and hydrogen sulfide accumulation near chamber walls was detected in the computational simulation, which also indicated that the positioning of the sampling tube in relation to the inlet orifices may lead to deviations in the measurement results. CFD results showed that the wall shear and concentration gradients spatially vary at the gas–liquid interface, and friction velocity inside the chamber does not match typical values of atmospheric flow. [Display omitted] •Air flow and H2S transportation in the US EPA flux chamber was studied applying CFD.•H2S emission rate from CFD was validated with mass transfer experiments.•Results show a fairly well mixed air phase in the chamber headspace.•A trend to stagnation and H2S accumulation near chamber walls was detected.•Friction velocity inside the chamber does not match typical values of atmospheric flow.
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content type line 23
ISSN:0045-6535
1879-1298
DOI:10.1016/j.chemosphere.2015.11.123