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Authors
Abstract(s)
Com o esgotamento das reservas de combustíveis fósseis e visando a redução
dos gases de efeito de estufa, como o CO2 e os NOx, tornou-se absolutamente
necessário procurar fontes energéticas mais ecológicas e renováveis, bem como, numa
ótica de valorização de resíduos, reciclar óleos alimentares usados e gordura animal,
na produção de biodiesel. Este biocombustível é produzido pela transesterificação
desses óleos vegetais com um álcool, como o metanol e, pode ser usado após a mistura
com diesel mineral.
O glicerol, subproduto do processo de transesterificação, é produzido em grande
escala e com pouco valor de mercado, o que levou à procura de alternativas na
utilização desse subproduto. Isso significa que novas aplicações para este poliol estão
a ser desenvolvidas, como a sua cetalização, produzindo cetais como aditivos diesel de
base biológica, como o Solketal.
O Solketal pode ser utilizado como um aditivo de combustível para reduzir as
emissões de NOx e melhorar as propriedades de fluxo a frio dos combustíveis de
transporte de líquidos.
O objetivo deste trabalho experimental consistiu em estudar a reação catalítica de
cetalização do glicerol com acetona, sob catálise heterogênea, utilizando catalisadores
microporosos como o Zeólito Y e duas argilas naturais, as montmorilonites K10 e K30.
Com esta reação, 2 enantiómeros são formados, sendo um deles o Solketal (98%).
Várias condições operatórias, tais como temperatura, quantidade de catalisador, razão
estequiométrica, presença e ausência de co-solvente e, diferentes tipologias de
catalisadores sólidos foram testadas.
Além disso, todo o Solketal produzido foi quantificado por refratometria e
viscosimetria, tendo sido posteriormente misturado com misturas biodiesel/diesel, para
analisar o efeito das suas propriedades físicas, como a viscosidade. As amostras
catalíticas foram caracterizadas por FTIR-ATR, SEM-EDS, por Difração de Raios X e,
pelas isotérmicas de adsorção através do modelo de BET, para cálculo da área
específica destes materiais.
With the depletion of fossil fuel reserves and aiming towards the reduction of greenhouse gases, such as CO2 and NOx, more ecological and renewable sources have been sought, as well, in a perspective of valorising solid and liquid wastes, recycling waste frying oils and animal fat, in the production of biodiesel. This biofuel is produced by transesterification of those vegetable oils with an alcohol, like methanol, and can be used after blending with fossil-based diesel. Glycerol, a by-product of the transesterification process, is produced on a large scale with little market value, which has led to the search for alternatives in using this by-product. This means that, new applications for this polyol are being developed, such as, its ketalization, producing glycerol ketals as bio-based diesel additives, like Solketal. Solketal can be used as a fuel additive to reduce the NOx emissions and to improve the cold flow properties of liquid transportation fuels. The aim of this experimental work was the study of the Solketal production by catalytic ketalization reaction of glycerol with acetone, under heterogeneous catalysis, using microporous materials, such as Zeolite Y and, two natural clays, montmorillonites K10 and K30. With this reaction, 2 enantiomers are formed, one of them being the Solketal (98%). Several operatory conditions, such as temperature, amount of catalyst, stoichiometric ratio, presence and absence of co-solvent and, different solid catalysts were tested. Besides that, all the Solketal produced was quantified by refractometry and viscosimetry and, after that, it was mixed with biodiesel/diesel mixtures, to analyse the effect of its physical properties, such as, viscosity. The catalysts’ samples were characterized by FTIR-ATR, SEM-EDS, XRD and BET, to quantify the correspondent specific areas of these materials.
With the depletion of fossil fuel reserves and aiming towards the reduction of greenhouse gases, such as CO2 and NOx, more ecological and renewable sources have been sought, as well, in a perspective of valorising solid and liquid wastes, recycling waste frying oils and animal fat, in the production of biodiesel. This biofuel is produced by transesterification of those vegetable oils with an alcohol, like methanol, and can be used after blending with fossil-based diesel. Glycerol, a by-product of the transesterification process, is produced on a large scale with little market value, which has led to the search for alternatives in using this by-product. This means that, new applications for this polyol are being developed, such as, its ketalization, producing glycerol ketals as bio-based diesel additives, like Solketal. Solketal can be used as a fuel additive to reduce the NOx emissions and to improve the cold flow properties of liquid transportation fuels. The aim of this experimental work was the study of the Solketal production by catalytic ketalization reaction of glycerol with acetone, under heterogeneous catalysis, using microporous materials, such as Zeolite Y and, two natural clays, montmorillonites K10 and K30. With this reaction, 2 enantiomers are formed, one of them being the Solketal (98%). Several operatory conditions, such as temperature, amount of catalyst, stoichiometric ratio, presence and absence of co-solvent and, different solid catalysts were tested. Besides that, all the Solketal produced was quantified by refractometry and viscosimetry and, after that, it was mixed with biodiesel/diesel mixtures, to analyse the effect of its physical properties, such as, viscosity. The catalysts’ samples were characterized by FTIR-ATR, SEM-EDS, XRD and BET, to quantify the correspondent specific areas of these materials.
Description
Trabalho final de mestrado para obtenção do grau de mestre em Engenharia Química e Biológica
Keywords
Biodiesel Glicerol Glycerol Solketal Catálise Heterogénea Heterogeneous Catalysis Montmorilonites
Citation
MARTINHO, Joana Filipa Paiva - Estudo da utilização de aditivo de baixo custo a combustíveis diesel, a partir da valorização do glicerol. Lisboa: Instituto Superior de Engenharia de Lisboa, 2018. Dissertação de mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa