Análise da influência do escoamento no interior de uma câmara de fluxo dinâmica na taxa de emissão de sulfeto de hidrogênio

• Ano de defesa: 2016
• Autor(a) principal: Andreão, Willian Lemker
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Espírito Santo; BR; Mestrado em Engenharia Ambiental; Centro Tecnológico; UFES; Programa de Pós-Graduação em Engenharia Ambiental
• Palavras-chave em Português: Odour sampling; odorous emissions; Flux hoods; Computational fluid dynamics; CFX; Câmara de fluxo dinâmica; ANSYS-CFX (Programa de computador); Amostragem de gases odorantes; Emissão de gases odorantes; Dinâmica dos fluidos computacional; Gases; Controle de odor; Sulfeto de hidrogênio; Fluidodinâmica computacional; Engenharia Sanitária; 628
• Link de acesso: http://repositorio.ufes.br/handle/10/10316

The wastewater treatment process lead to formation of odorous compounds, as hydrogen sulphide (H2S), which can cause nuisance and disturbance to health of nearby residents. The dynamic flux chamber (or flux hood) is widely used to estimate the emission of odorous gases from quiescent liquid surfaces, presented in wastewater treatment plants. The geometry of the flux hood must promote a complete mixing of the volatilized gas within the hood to the emission measured be independent of the point sampling. An auxiliary device, as a small fan, it is commonly used for this purpose. This study investigated the influence of the flow inside the chamber on the transport of H2S and its emission rate. Mathematical modeling of these phenomena was performed through the numerical solution of the transport equations considering the turbulent flow using ANSYS-CFX 14.5 code. The results show that a flux hood with eight air inlets promote a concentration distribution more homogeneous, although the friction velocity at interface (0.007 m s-1 ) is not sufficient to promote an appropriate sweeping on interface, where it is found high values of concentration. In standard configuration (US EPA model), with four inlets, clean air jet can reaches the sampling probe, affecting in the concentration values measured. If micro fans are used, turbulence created within the hood and friction velocity are significantly higher. Concentration quickly reaches stationary state within the hood (1 to 2 min) and the final emission rate is on average 25.3% higher with the use of micro fans. If the purpose of using the flux hood is to represent environmental conditions that would be found in the field, it is recommended to use micro fans.