@MastersThesis{Souza:2016:EfAdZi,
author = "Souza, Amanda Cassiano de",
title = "Efeito da adi{\c{c}}{\~a}o da zirc{\^o}nia em aluminas
empregadas como suporte de catalisadores",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2016",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2016-05-25",
keywords = "alumina, {\'o}xido de zirc{\^o}nio, catalisadores,
propuls{\~a}o espacial, refino de petr{\'o}leo, zirconium oxide,
catalyst, space propulsion, petroleum refining.",
abstract = "Na busca pelo aumento do desempenho de rea{\c{c}}{\~o}es
catal{\'{\i}}ticas heterog{\^e}neas, compostos contendo
elementos dopantes s{\~a}o adicionados a suportes e
catalisadores, alterando suas propriedades morfol{\'o}gicas,
mec{\^a}nicas e texturais. Conforme citado em in{\'u}meras
refer{\^e}ncias bibliogr{\'a}ficas, a adi{\c{c}}{\~a}o de
{\'o}xido de zirc{\^o}nio em alguns suportes de catalisadores
pode alterar as suas propriedades, sobretudo a acidez superficial
desses materiais. Neste trabalho, buscou-se avaliar a
influ{\^e}ncia da presen{\c{c}}a do {\'o}xido de zirc{\^o}nio
na alumina, adicionando este elemento antes da etapa de
forma{\c{c}}{\~a}o do seu hidr{\'o}xido precursor ou por
impregna{\c{c}}{\~a}o da alumina, ap{\'o}s
calcina{\c{c}}{\~a}o do seu composto precursor. As aluminas
modificadas em sua origem e os catalisadores obtidos ap{\'o}s
impregna{\c{c}}{\~a}o de fases ativas foram avaliadas em
rea{\c{c}}{\~o}es catal{\'{\i}}ticas heterog{\^e}neas
aplicadas. Na propuls{\~a}o espacial, al{\'e}m dos aspectos
mec{\^a}nicos e t{\'e}rmicos, o poss{\'{\i}}vel efeito do
{\'o}xido de zirc{\^o}nio na acidez da matriz alumina foi
avaliado na rea{\c{c}}{\~a}o de decomposi{\c{c}}{\~a}o da
am{\^o}nia. Este g{\'a}s {\'e} formado durante a
decomposi{\c{c}}{\~a}o catal{\'{\i}}tica da hidrazina no
decorrer do acionamento dos propulsores de controle de {\'o}rbita
e atitude de sat{\'e}lites. Sendo esta rea{\c{c}}{\~a}o de
decomposi{\c{c}}{\~a}o endot{\'e}rmica, o seu controle pode
reduzir a temperatura de opera{\c{c}}{\~a}o do propulsor,
aumentando a vida {\'u}til do catalisador no sat{\'e}lite. No
refino de petr{\'o}leo, procurou-se avaliar o efeito do
{\'o}xido de zirc{\^o}nio n{\~a}o somente na acidez da alumina,
mas tamb{\'e}m na atividade e seletividade dos catalisadores,
obtidos a partir desse suporte, na rea{\c{c}}{\~a}o de
hidrodessulfuriza{\c{c}}{\~a}o (HDS). As aluminas foram
preparadas a partir de seu hidr{\'o}xido de alum{\'{\i}}nio.
Este composto precursor foi ent{\~a}o moldado e, posteriormente
submetido a tratamentos t{\'e}rmicos para sua
transforma{\c{c}}{\~a}o em alumina ativa ou de
transi{\c{c}}{\~a}o. A incorpora{\c{c}}{\~a}o da zirc{\^o}nia
ocorreu de duas diferentes formas. Na primeira, antes da etapa de
forma{\c{c}}{\~a}o do hidr{\'o}xido de alum{\'{\i}}nio e na
segunda, por impregna{\c{c}}{\~a}o incipiente, ap{\'o}s a
obten{\c{c}}{\~a}o da alumina. A prepara{\c{c}}{\~a}o dos
catalisadores tamb{\'e}m foi realizada com aux{\'{\i}}lio da
t{\'e}cnica de impregna{\c{c}}{\~a}o incipiente dos suportes.
Os metais selecionados para avalia{\c{c}}{\~a}o em
rea{\c{c}}{\~o}es do refino foram o molibd{\^e}nio (Mo) e o
n{\'{\i}}quel (Ni), elementos mais utilizados em catalisadores
comerciais. Os materiais preparados neste trabalho foram
caracterizados por in{\'u}meras t{\'e}cnicas, entre elas
volumetria de N\$_{2}\$ (BET), difratometria de raios X (DRX),
dinamometria, quimissor{\c{c}}{\~a}o com mol{\'e}culas sonda
(TPD) e espectroscopia de infravermelho com transformada de
Fourier (FTIR). As aluminas foram avaliadas em uma unidade
catal{\'{\i}}tica de bancada na rea{\c{c}}{\~a}o de
decomposi{\c{c}}{\~a}o da NH\$_{3}\$, etapa realizada no
Laborat{\'o}rio Associado de Combust{\~a}o e Propuls{\~a}o
(LCP) do INPE. Os catalisadores impregnados com os metais Ni e Mo
foram avaliados na rea{\c{c}}{\~a}o de
hidrodessulfuriza{\c{c}}{\~a}o (HDS) do dibenzotiofeno (DBT), em
uma unidade catal{\'{\i}}tica de alta press{\~a}o de bancada
(UHP), etapa conduzida no Laborat{\'o}rio de Cat{\'a}lise
(LABCAT) da UNIVAP. ABSTRACT: In order to increase performance of
heterogeneous catalytic reactions, compounds containing doping
elements are added to supports and catalysts, altering their
morphological, mechanical, and textural properties. As mentioned
in several literature references, addition of zirconium oxide in
some catalyst supports can alter their properties, mainly
regarding surface acidity of such materials. This work had the
objective of evaluating the influence of zirconium oxide in
alumina, adding this element before the formation step of its
precursor hydroxide or by alumina impregnation, after calcination
of its precursor compound. Modified aluminas in their origin, as
well as catalysts obtained after impregnation of active phases,
were evaluated in applied heterogeneous catalytic reactions.
Besides mechanical and thermal aspects of space propulsion, a
possible effect of zirconium oxide in the acidity of alumina
matrix was evaluated regarding the ammonium decomposition
reaction. This gas is formed from hydrazine catalytic
decomposition throughout start up of satellites for orbit control
and attitude. Since it is an endothermic decomposition reaction,
its control may reduce the thruster operational temperature,
increasing the catalyst useful life in the satellite. The effect
of zirconium oxide was evaluated in the case of petroleum
refining, not only regarding alumina acidity but also in catalyst
activity and selectivity, which are obtained from this support in
the hydrodesulphurization reaction (HDS). Aluminas were prepared
by employing aluminum hydroxide. This precursor compound was then
molded and later submitted to thermal treatments for its
transformation into active or transition alumina. Zircon
incorporation occurred through two manners. In the first case, it
occurred in the step of aluminum hydroxide formation, and in the
second case it happened by incipient impregnation, after alumina
obtainment. Catalyst preparation was also done by using the
incipient impregnation technique for supports. Molybdenum (Mo) and
nickel (Ni) were metals selected for evaluation of refining
reactions, since they are the most common elements used in
commercial catalysts. Materials prepared in this study were
characterized by several techniques, such as N\$_{2}\$ Volumetry
(BET), X-Ray Diffractometry (DRX), dynamometry, Chemisorption with
probe molecules (TPD), and Fourier Transform Infrared Spectroscopy
(FTIR). Aluminas were evaluated by employing a bench catalytic
unit during the NH\$_{3}\$ decomposition reaction, which was
accomplished at the Combustion and Propulsion Associated
Laboratory (LCP) from INPE. Impregnated catalysts with Ni and Mo
metals were evaluated in the hydrodesulphurization reaction (HDS)
of dibenzothiophene (DBT), by employing a high pressure catalytic
bench unit (UHP). This step was conducted at UNIVAP Catalysis
Laboratory (LABCAT).",
committee = "Nono, Maria do Carmo de Andrade (presidente/orientadora) and
Rodrigues, Jos{\'e} Augusto Jorge (orientador) and Soares Neto,
Tur{\'{\i}}bio Gomes and Ferreira, Marco Aur{\'e}lio",
copyholder = "SID/SCD",
englishtitle = "Effect of addition zirconia in the aluminas employed as catalyst
support",
language = "pt",
pages = "106",
ibi = "8JMKD3MGP3W34P/3LLMKHE",
url = "http://urlib.net/ibi/8JMKD3MGP3W34P/3LLMKHE",
targetfile = "publicacao.pdf",
urlaccessdate = "27 abr. 2024"
}