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Previous issue date: 2015-03-05 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Na ind?stria do petr?leo, a ?gua produzida ? o maior volume l?quido produzido com
grande capacidade poluidora. Dentre os contaminantes org?nicos, os arom?ticos apresentam o
principal risco ao meio ambiente e ? sa?de da popula??o principalmente BTEX. Ao longo dos
?ltimos anos, a eletroqu?mica tem se mostrado eficiente na degrada??o desses compostos,
envolvendo apenas a utiliza??o de el?trons como reagentes. Entretanto, o desenho do reator
eletroqu?mico, hidrodin?mica e, consequentemente, o coeficiente de transfer?ncia de massa
s?o par?metros determinantes na efici?ncia do processo eletroqu?mico. Dentro desse contexto,
o objetivo deste trabalho foi investigar geometrias de c?lulas eletroqu?micas, visando
determinar os coeficientes de transfer?ncia de massa e entender a sua hidrodin?mica. Foram
estudadas c?lulas em batelada e em fluxo, variando a pot?ncia da agita??o, posi??o da
agita??o e espa?amento entre os eletrodos, empregando a t?cnica de corrente limite, com um
gradiente de concentra??o de 4 a 24 mmol/dm? de K4[Fe(CN)]6 em propor??o molar de 2:1
para K3[Fe(CN)]6 em meio de NaOH 0,5 mol/dm?, a fim de determinar a corrente limite, e
consequentemente o coeficiente de transfer?ncia de massa (km). Os resultados obtidos
mostraram claramente que na c?lula em batelada, o aumento da agita??o e a posi??o da
agita??o influenciaram o km; na c?lula em fluxo, o afastamento dos eletrodos n?o mostra
influencia significativa quando a agita??o (fluxo) ? direcionada ? superf?cie do eletrodo; e
ainda, as c?lulas em fluxo se mostraram mais eficientes no que diz respeito ? elimina??o de
resist?ncias f?sicas inerentes ao tratamento eletro-oxidativo. Por fim, os resultados alcan?ados
mostraram que ? poss?vel a aplica??o do reator eletroqu?mico no tratamento de BTX, uma vez
que foi identificada uma geometria com o melhor coeficiente de massa, favorecendo a
oxida??o das esp?cies na superf?cie do eletrodo, de forma mais r?pida e eficiente. / The oil and gas production processes generate large volumes of waste with high
toxicity. In this industry, produced water is the most produced liquid volume with great
polluting capacity. Among the organic contaminants, the aromatics, mainly BTEX, present a
major risk to the environment and people's health. Over the past years, many studies have
been conducted under the electrooxidation of aromatic compounds, showing that the
electrochemical degradation is efficient for these substances, even more importantly, the
process involves only the use of electrons as reactants. However, the design of the
electrochemical reactor, hydrodynamics and mass transfer coefficients are critical parameters
on the efficiency of the electrochemical process. In this context, the objective of this study
was to investigate geometries of electrochemical cells, to determine the mass transfer
coefficients and understand their hydrodynamics. Cells were studied in batch and flow design,
varying stirring rate, the stirring position and spacing between electrodes. In order to
determine the current limit, and thus the mass transfer coefficient (Km), it was used a
concentration gradient of K4[FeCN]6 / K3[FeCN]6 (2:1) from 4 to 24 mM, in medium of 0.5
M NaOH. The results clearly showed that regarding the batch cell, increasing stirring rate and
changing its position promote a considerable effect on Km; in the flow cell, no influences were
achieved when the spacing of the electrodes was modified when the stirring (flow) is directed
to the electrode surface; and, the flow cells are more efficient with regard to the elimination of
inherent physical resistance to the electrochemical treatment. Finally, the results showed that
the application of reactor is possible to treat electrochemically BTX because the better
geometry has been identified, favoring the oxidation of the species on the electrode surface
more rapidly and efficiently.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/20336 |
| Date | 05 March 2015 |
| Creators | N?brega, Diogo Rosembergh da Silva |
| Contributors | 01139059980, http://lattes.cnpq.br/2485073932883264, Silva, Djalma Ribeiro da, 13893734449, http://lattes.cnpq.br/2791074318745945, Ara?jo, Danyelle Medeiros de, 00974778427, http://lattes.cnpq.br/5376210566183962, Moura, Dayanne Chianca de, 04719087469, http://lattes.cnpq.br/5569739045933136, Castro, Suely Souza Leal de, 05705753896, http://lattes.cnpq.br/9860381828526444, Huitle, Carlos Alberto Martinez |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM CI?NCIA E ENGENHARIA DE PETR?LEO, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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