@PhDThesis{Souza:2022:CaSuAl,
author = "Souza, Amanda Cassiano de",
title = "Catalisadores suportados em aluminas dopadas para
decomposi{\c{c}}{\~a}o do per{\'o}xido de hidrog{\^e}nio em
propulsores de sat{\'e}lites",
school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
year = "2022",
address = "S{\~a}o Jos{\'e} dos Campos",
month = "2022-08-05",
keywords = "catalisador, {\'o}xidos mistos, per{\'o}xido de hidrog{\^e}nio,
propuls{\~a}o, catalyst, mixed oxides, hydrogen peroxide,
propulsion.",
abstract = "Ap{\'o}s v{\'a}rias d{\'e}cadas de dom{\'{\i}}nio da
hidrazina como propelente de propulsores de sat{\'e}lites, sua
utiliza{\c{c}}{\~a}o come{\c{c}}ou a ser questionada em
fun{\c{c}}{\~a}o do seu perigo {\`a} sa{\'u}de humana e ao
meio ambiente. Uma das alternativas {\`a} hidrazina {\'e} o uso
do per{\'o}xido de hidrog{\^e}nio (H2O2), monopropelente
classificado como sendo verde, uma vez que sua
decomposi{\c{c}}{\~a}o gera os compostos qu{\'{\i}}micos
{\'a}gua e oxig{\^e}nio, ou seja, n{\~a}o causam impactos ao
meio ambiente e {\`a} sa{\'u}de humana. Buscando agregar
aspectos inovadores que possam melhorar a atividade dos
catalisadores empregados na decomposi{\c{c}}{\~a}o do H2O2, o
presente trabalho tem como objetivos, sintetizar uma alumina
modificada, adicionando um elemento dopante, sil{\'{\i}}cio ou
boro, durante a etapa de forma{\c{c}}{\~a}o do hidr{\'o}xido de
alum{\'{\i}}nio, a fim de melhor as caracter{\'{\i}}sticas
texturais, mec{\^a}nicas e t{\'e}rmicas da alumina. O
hidr{\'o}xido precursor contendo o dopante sil{\'{\i}}cio
resultou na forma{\c{c}}{\~a}o da fase cristalina boemita e,
ap{\'o}s calcina{\c{c}}{\~a}o, da fase cristalina gama-alumina
com elevados valores de {\'a}rea e volume de poros. A
obten{\c{c}}{\~a}o de aluminas moldadas envolveu uma etapa de
dispers{\~a}o das part{\'{\i}}culas, denominada de
peptiza{\c{c}}{\~a}o, realizada com aux{\'{\i}}lio de agentes
qu{\'{\i}}micos, etapa fundamental para a gera{\c{c}}{\~a}o de
pellets com elevada resist{\^e}ncia mec{\^a}nica. Foram
realizados dois tipos de processos, o convencional, denominado de
peptiza{\c{c}}{\~a}o incipiente, e o alternativo, visando
melhorar a resist{\^e}ncia mec{\^a}nica, denominado de
peptiza{\c{c}}{\~a}o em excesso. Os pellets de hidr{\'o}xido de
alum{\'{\i}}nio (antes da calcina{\c{c}}{\~a}o) e alumina
(ap{\'o}s calcina{\c{c}}{\~a}o) modificados com
sil{\'{\i}}cio ou boro foram submetidos {\`a} etapa de
esferoidiza{\c{c}}{\~a}o, pelo m{\'e}todo de
fluidiza{\c{c}}{\~a}o com ar, para obten{\c{c}}{\~a}o de
part{\'{\i}}culas esferoidais, formato empregado no catalisador
comercial Shell 405. O hidr{\'o}xido de alum{\'{\i}}nio
contendo sil{\'{\i}}cio resultou nas part{\'{\i}}culas
esferoidais com melhor rendimento. Catalisadores foram preparados
contendo como fase ativa os metais, o mangan{\^e}s, o cobalto, o
bismuto, o n{\'{\i}}quel e o molibd{\^e}nio. Esses metais
selecionados s{\~a}o considerados mais ativos por serem
c{\'a}tions de metais de transi{\c{c}}{\~a}o. Foram preparados
catalisadores m{\'a}ssicos para avalia{\c{c}}{\~a}o nos testes
de gota e de bancada, e catalisadores suportados na alumina
contendo sil{\'{\i}}cio para avalia{\c{c}}{\~a}o no
micropropulsor. Com rela{\c{c}}{\~a}o {\`a}
impregna{\c{c}}{\~a}o do suporte com a fase ativa, empregou-se
dois procedimentos, um tradicional, ou seja, solubilizando os
metais que constituem a fase ativa em meio aquoso, e o outro,
propondo uma t{\'e}cnica inovadora de impregna{\c{c}}{\~a}o,
solubilizando-os em meio org{\^a}nico, denominada processo
poliol. Os materiais preparados foram caracterizados pelas
t{\'e}cnicas de volumetria de nitrog{\^e}nio (BET),
difratometria de raios X (DRX), termogravimetria (TG),
resist{\^e}ncia mec{\^a}nica por compress{\~a}o individual,
densidade real (DR). Os catalisadores m{\'a}ssicos foram
pr{\'e}avaliados atrav{\'e}s do teste de gota (drop test), com o
gotejamento de H2O2 na superf{\'{\i}}cie do catalisador, com o
objetivo de verificar a atividade do material na
decomposi{\c{c}}{\~a}o do H2O2, associando essa atividade ao
volume dos gases liberados em fun{\c{c}}{\~a}o do tempo. De
forma qualitativa, inicialmente os testes foram monitorados por
uma c{\^a}mera fotogr{\'a}fica de alta velocidade. Foi
desenvolvido um teste de bancada capaz de estimar, de forma
simples e r{\'a}pida, a atividade de catalisadores frente {\`a}
rea{\c{c}}{\~a}o de decomposi{\c{c}}{\~a}o do H2O2 de forma
quantitativa. O melhor catalisador, ou seja, o mais ativo, nos
testes de bancada, contendo a fase ativa mangan{\^e}s-cobalto,
foi selecionado para avalia{\c{c}}{\~a}o em testes de bancada em
um sistema micropropulsivo equipado com um propulsor de 2N, que
indicaram que o catalisador suportado na alumina com
sil{\'{\i}}cio e preparado pelo novo m{\'e}todo, poliol,
resultou em valores superiores de empuxo e press{\~a}o de
c{\^a}mera. ABSTRACT: After several decades of hydrazine
dominance as a propellant for satellite propellants, its use began
to be questioned due to its danger to human health and the
environment. One of the alternatives to hydrazine is the use of
hydrogen peroxide (H2O2), a monopropellant classified as being
green, since its decomposition generates the chemical compounds
water and oxygen, that is, it does not cause impacts to the
environment and human health. . Seeking to add innovative aspects
that can improve the activity of catalysts used in the
decomposition of H2O2, the present work aims to synthesize a
modified alumina, adding a dopant element, silicon or boron,
during the aluminum hydroxide formation step, in order to better
the textural, mechanical and thermal characteristics of alumina.
The precursor hydroxide containing the silicon dopant resulted in
the formation of the boehmite crystalline phase and, after
calcination, of the gamma-alumina crystalline phase with high
values of pore area and volume. Obtaining molded alumina involved
a particle dispersion step, called peptization, carried out with
the aid of chemical agents, a fundamental step for the generation
of pellets with high mechanical strength. Two types of processes
were carried out, the conventional one, called incipient
peptization, and the alternative, aiming to improve the mechanical
resistance, called excess peptization. The aluminum hydroxide
pellets (before calcination) and alumina (after calcination)
modified with silicon or boron were subjected to the
spheroidization step, by the air fluidization method, to obtain
spheroidal particles, a format used in the commercial catalyst
Shell 405. Aluminum hydroxide containing silicon resulted in the
spheroidal particles with the best yield. Catalysts were prepared
containing as active phase the metals, manganese, cobalt, bismuth,
nickel and molybdenum. These selected metals are considered more
active because they are transition metal cations. Mass catalysts
were prepared for evaluation in the drop and bench tests, and
catalysts supported on alumina containing silicon for evaluation
in the micropropeller. Regarding the impregnation of the support
with the active phase, two procedures were used, one traditional,
that is, solubilizing the metals that constitute the active phase
in an aqueous medium, and the other, proposing an innovative
technique of impregnation, solubilizing them in water. organic
medium, called polyol process. The prepared materials were
characterized by the techniques of nitrogen volumetry (BET), X-ray
diffraction (XRD), thermogravimetry (TG), mechanical strength by
individual compression, real density (DR). The mass catalysts were
pre-evaluated through the drop test, with the dripping of H2O2 on
the surface of the catalyst, with the objective of verifying the
activity of the material in the decomposition of the H2O2,
associating this activity with the volume of gases released in
time function. Qualitatively, initially the tests were monitored
by a high-speed camera. A bench test was developed capable of
estimating, in a simple and fast way, the activity of catalysts
against the decomposition reaction of H2O2 in a quantitative way.
The best catalyst, that is, the most active, in the bench tests,
containing the manganese-cobalt active phase, was selected for
evaluation in bench tests in a micropropulsive system equipped
with a 2N propellant, which indicated that the catalyst supported
in the alumina with silicon and prepared by the new method,
polyol, resulted in superior values of thrust and chamber
pressure.",
committee = "Rodrigues, Jos{\'e} Augusto Jorge (orientador/presidente) and
Nono, Maria do Carmo de Andrade (orientadora) and Machado,
Jo{\~a}o Paulo Barros and Silva, Adriana Maria da and Oliveira,
Ivone Regina de and Cruz, Gilberto Marques da",
englishtitle = "Catalyst supported on aluminas doped for decomposition of hydrogen
peroxide in satellite propellers",
language = "pt",
pages = "145",
ibi = "8JMKD3MGP3W34T/47GU3DB",
url = "http://urlib.net/ibi/8JMKD3MGP3W34T/47GU3DB",
targetfile = "publicacao.pdf",
urlaccessdate = "21 maio 2024"
}