Mitigation of climate change and energy security are major driving forces for increased biomass utilization. The pulp and paper industry consumes a large proportion of the biomass worldwide including bark, wood residues, and black liquor. Due to the fact that modern mills have established infrastructure for handling and processing biomass, it is possible to lay foundation for future gasification based bio-refineries to poly-produce electricity, chemicals or bio-fuels together with pulp and paper products. There is a potential to export electricity or bio-fuels by improving energy systems of existing chemical pulp mills by integrating gasification technology. The present study investigates bio-fuel alternatives from the dry black liquor gasification (BLG) system with direct causticization and direct methane production from the catalytic hydrothermal gasification (CHG) system. The studied systems are compared with bio-fuel alternatives from the Chemrec BLG system and the improvements in the energy systems of the pulp mill are analyzed. The results are used to identify the efficient route based on system performance indicators e.g. material and energy balances to compare BLG systems and the conventional recovery boiler system, potential biofuel production together with biomass to biofuel conversion efficiency, energy ratios, potential CO2 mitigation combining on-site CO2 reduction using CO2 capture and potential CO2 offsets from biofuel use, and potential motor fuel replacement. The results showed that the dry BLG system for synthetic natural gas (SNG) production offers better integration opportunities with the chemical pulp mill in terms of overall material and energy balances. The biofuel production and conversion efficiency are higher in the CHG system than other studied configurations but at a cost of larger biomass import. The dry BLG system for SNG production achieved high biomass to biofuel efficiency and considerable biofuel production. The energy ratio is significant in the dry BLG (SNG) system with less biomass demand and considerable net steam production in the BLG island. The elimination of the lime kiln in the dry BLG systems resulted in reduced consequences of incremental biomass import and associated CO2 emissions. Hydrogen production in the dry BLG system showed the highest combined CO2 mitigation potential i.e. on-site CO2 capture potential and CO2 offset from biofuel replacing fossil fuel. The results also showed that the motor fuel replacement potential with SNG as compressed natural gas (CNG) replacing gasoline in the transport sector is significantly high in countries with large pulp industry. / QC 20120528

The research institute ETC in Piteå is working with energy technical research and development. Today, much work revolves around research about renewable sources for fuel. In one project, biomass such as wood pellet is heated up while producing synthesis gas. The synthesis gas is then analyzed using three different GC techniques. ETC wanted to be able to make all their analysis on one instrument and with a faster speed. They contacted the company Rowaco in Linköping for help with developing a method on FTIR for analysis of the synthesis gas and that has been the aim for this thesis. A method has been developed for analysis of water, carbon monoxide, carbon dioxide and methane. The results from this thesis show that the concentrations of the molecules in the synthesis gas are outside the calibration curved that has been made and that the high concentrations give much interference to other molecules. The thesis also shows that many areas in the spectrum from the process are roof absorbers and there is also a contamination of water and carbon dioxide in the system. Suggested improvements are to find the source for the contamination, to develop calibration points with higher concentrations, to reduce the length of the gas cell and to dilute the gas before entering the FTIR.

Increasing prices of crude oil derived transportation fuels ascended the researches on seeking alternative fuels, in last decades. Moreover, the increasing rate of global warming, because of high greenhouse gas emissions initiated new research for environment-friendly clean alternative fuels. Due to its low NOx emission, good burning characteristics and high cetane number, dimethyl ether (DME) attracted major attention as a transportation fuel alternative. Two possible pathways have been proposed for DME production. One of these pathways is DME synthesis through conventional methanol dehydration. More recently, direct DME synthesis in a single step has attracted significant attention of researchers and fuel producers. Catalysts having two active sites are required for direct DME synthesis from synthesis gas. The aim of this work was to synthesize novel bifunctional direct DME synthesis catalysts and test their activity in a high pressure fixed bed flow reactor. Bifunctional mesoporous catalysts were synthesized by using one-pot hydrothermal synthesis, impregnation and physical mixing methods. These materials were characterized by XRD, EDS, SEM, N2 physisorption and diffuse reflectance FT-IR (DRIFTS) techniques. Characterization results of the catalysts synthesized by one-pot hydrothermal synthesis procedures in basic and acidic routes showed that pH value of the synthesis solution was highly effective on the final physical structure and chemical nature of the catalysts. Increase in the pH value promoted the incorporation of Cu, Zn and Al into the mesoporous MCM-41 structure. Also, effects of Na2CO3 addition on the catalyst structure during the hydrothermal synthesis procedure were investigated. The characterization results showed that metals were incorporated into the catalyst structure successfully. However, surface area results showed that loaded metals blocked the pores of MCM-41 and decreased the surface area of the catalysts. Effects of zirconium (Zr) metal with different weight ratios were also investigated. Results showed that Zr loading increased the surface area of the catalyst. A high pressure fixed bed flow reactor was built and the catalyst testing experiments were performed between the temperature range of 200-400&deg / C, at 50 bars. The activity results of the catalyst synthesized by impregnation method showed that no DME was formed over this catalyst / however it showed promising results for production of methanol and ethanol. Selectivity values of these alcohols were between 0.35 and 0.2. Formation of methane and CO2 indicated the occurrence of reverse dry reforming reaction. Incorporation of Zr into the catalyst structure at neutral synthesis condition caused significant activity enhancement, giving CO conversion values of about 40% at 400&deg / C. Product distribution obtained with this catalyst indicated the formation of DME, ethanol, methanol as well as CH4 and CO2. Highest DME selectivity (60%) was observed with the catalyst prepared by physical mixing of commercial methanol reforming catalyst with silicotungstic acid incorporated methanol dehydration catalyst having W/Si ratio of 0.4.

Hydrocarbon conversion and synthesis gas production are two components of the power production process that require significant development and exploration in the advanced energy arena. To remain within our current fueling infrastructure, it is imperative that an efficient and reliable mechanism to facilitate these components of the power production process is developed for automotive applications. A honeycomb monolith rhodium based catalyst has been identified as a potential fuel reformer element for use in automotive hydrocarbon fuel conversion. Using the novel and minimally invasive SpaciMS (Spatially resolved capillary inlet Mass Spectroscopy), developed at Oak Ridge National Laboratories, and an internal temperature acquisition system, the impact of fuel inlet space velocity on the operating rhodium based catalytic fuel reformer of interest was parametrically studied. In situ temperature and species profiles of the catalyst during steady state operation were produced. The data acquired through these experiments was then used to demonstrate analytic capability by conducting thermodynamic analyses on the operating fuel reformer. Experimental and analytical results can be used in development of design considerations for fuel conversion systems.

Thesis (M.S.) -- Mississippi State University. Dave C. Swalm School of Chemical Engineering. / Title from title screen. Includes bibliographical references.

Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request

A tecnologia Coal, Gas or Biomass-To-Liquids (XTL) permite a obtenção de combustíveis líquidos a partir de biomassa, carvão mineral ou gás natural. A síntese de catalisadores otimizados constitui um desafio para aumentar a viabilidade desses processos. Neste contexto, por exibirem propriedades catalíticas interessantes para diferentes processos químicos, os óxidos mistos apresentam-se como alternativas promissoras. Entretanto, a sua aplicação nesta tecnologia ainda requer maior investigação. A proposta da tese foi a de avaliar catalisadores baseados em óxidos mistos para a geração de gás de síntese a partir da decomposição do etanol e da reforma do etanol ou do metano. Foram preparadas amostras Fe-Al, Co-Al e Ni-Al pelo método da co-precipitação, sendo caracterizadas por diferentes técnicas. As reações foram conduzidas em reatores tubulares de leito fixo, com alimentação contínua dos reagentes gasosos e líquidos e com análise por cromatografia gasosa. Um melhor compromisso entre propriedades e desempenho catalítico na reação de decomposição do etanol foi observado para amostras com razões molares Ni2+/Al3+ entre 1 e 3, pois esta composição favoreceu a formação dos óxidos mistos. Para materiais baseados em Fe, Co ou Ni, houve a formação de materiais do tipo hidrotalcita nos precursores dos catalisadores Co-Al e Ni-Al, formando óxidos mistos após o tratamento térmico. Foram observadas conversões de etanol e seletividade para H2 e CO mais altas na reação de decomposição do etanol sobre estas amostras. Catalisadores à base de ferro conduziram à maior formação de eteno e acetaldeído e menor deposição de coque. A substituição parcial de Ni por um terceiro elemento modificou o perfil de redução e diminuiu a acidez das amostras. Nas amostras Ni-Al, os catalisadores contendo Zn, Mo ou Co apresentaram maior atividade na reação de reforma a vapor do etanol nas temperaturas de 400 e 450°C. Um aumento na redutibilidade e na área específica foi verificado com a substituição parcial de ferro por cobre ou cobalto nas amostras Fe-Al. A melhoria nas propriedades do material resultou em desempenho superior nos testes de reforma a vapor do etanol, especialmente para o catalisador Co-Fe-Al. Em relação à reforma do metano, foram investigadas amostras Co-Al modificadas com um terceiro elemento. A substituição parcial de Co por um elemento de maior alcalinidade propiciou um incremento na área específica e modificações no perfil de redução, na força ou quantidade de sítios alcalinos e na cristalinidade do material. As alterações nas propriedades do material proporcionaram menor formação de coque, sendo mantidas ou elevadas as conversões de CH4 e CO2. O catalisador Mg-Co-Al apresentou os melhores resultados de atividade, especialmente para o catalisador com razão molar Mg/Co = 0,5 e para ativação na temperatura de 500°C. Desta forma, foi possível avaliar as diferenças entre óxidos mistos contendo diferentes metais ativos para a geração do gás de síntese, bem como a otimização destes catalisadores por meio da adição de promotores. Os óxidos mistos exibiram alta área específica, elevada estabilidade térmica e moderada acidez que conduziram a melhores desempenhos nos diferentes processos estudados. / The Coal or Gas or Biomass-To-Liquids (XTL) technology allows the production of liquid fuels from biomass, mineral coal or natural gas. The synthesis of optimized catalysts is a great challenge for improving the feasibility of these processes. In this context, mixed oxides are promising alternatives as they exhibit interesting catalytic properties for different chemical processes. However, its application for XTL processes still requires further investigation. The purpose of this thesis was to evaluate catalysts based on mixed oxides for the generation of synthesis gas through the decomposition of ethanol and the reforming of ethanol or methane. Fe-Al, Co-Al and Ni-Al samples were prepared by the co-precipitation method and characterized by different techniques. The reactions were conducted using tubular fixed bed reactors. The gaseous and liquid feedstocks were fed continuously and the analysis was performed by gas chromatography. A better commitment between the properties and catalytic performance for the decomposition of ethanol was observed for samples with Ni2+/Al3+ molar ratios between 1 and 3 because this composition favored the formation of the mixed oxides. For the Fe-, Coor Ni-based materials, the formation of hydrotalcite-type materials was identified in the precursors of the Co-Al and Ni-Al catalysts and thus yielding mixed oxides after thermal treatment. Higher conversion of ethanol and selectivity towards H2 and CO for the decomposition of ethanol was observed for these samples. The iron-based catalysts led to higher formation of ethylene and acetaldehyde and a decrease on the coke deposition. The partial substitution of Ni by a third element modified the reduction profile and decreased the acidity of samples. For the Ni-Al samples, the catalysts containing Zn, Mo or Co showed higher activity for the steam reforming of ethanol at 400 and 450°C. An increase in the reducibility and in the specific surface area was verified when iron is partly substituted by copper or cobalt in the Fe-Al samples. The improvement in the properties of the material resulted in a better performance for the steam reforming of ethanol, especially for the Co-Fe-Al catalyst. Regarding the reforming of methane, different Co-Al samples modified with a third element were investigated. The partial substitution of Co by an element with higher basicity provided an increase in the specific surface area and modifications on the reduction profile, in the strength or quantity of the alkalinity sites and in the overall crystallinity of the material. The changes in the properties provided smaller coke formation while maintaining or even increasing the CO2 and CH4 conversions. The Mg-Co-Al catalyst exhibited the best activity results, especially for the catalyst with Mg/Co molar ratio of 0.5 and for activation at 500°C. Therefore, it was possible to evaluate the differences between the mixed oxides based on different active metals for the generation of the synthesis gas, as well as the optimization of these catalysts through the addition of promoters. The mixed oxides exhibited high specific surface area, high thermal stability and moderate acidity that led to better performance for the different studied processes.

A fermentação anaeróbia da matéria orgânica produz uma mistura de gases chamada biogás. Este biogás contém CH4 e CO2 como componentes majoritários. Estes dois compostos são gases de efeito estufa e sua utilização é muito importante do ponto de vista ambiental e econômico. O presente trabalho teve por objetivo produzir gás de síntese (H2/CO), uma matéria prima de alto valor industrial, a partir da reforma oxidativa do biogás com adição de oxigênio (1,5CH4+1,0CO2+0,25O2) sobre catalisadores de NiO-MgO-ZrO2 e NiO-Y2O3-ZrO2. Os catalisadores foram preparados usando o método de polimerização numa única etapa e foi estudada a variação do teor de MgO e de Y2O3 contido nas amostras. Estes materiais foram caracterizados por DRX, RTP, Adsorção-dessorção de N2, XPS, XAS-XANES, MEV e EDX e foram avaliados na reação de reforma oxidativa de um biogás modelo (composição molar:1,5 CH4/1CO2) em presença de oxigênio, a 750&deg;C e 1atm, visando à obtenção de gás de síntese. Os teores de MgO utilizados no sistema NiO/MgO/ZrO2 foram de 0%, 4%, 20%, 40% e 100% em relação ao ZrO2 (os mesmos teores foram utilizados para Y2O3 no sistema NiO/Y2O3/ZrO2) e o teor mássico de Ni foi 20%. As análises de DRX, TPR, XPS confirmaram a formação das soluções sólidas NiO-MgO e MgO-ZrO2 nos catalisadores NiO-MgO-ZrO2, e das soluções sólidas NiO-Y2O3 e Y2O3-ZrO2 nos catalisadores NiO-Y2O3-ZrO2. Estas soluções sólidas juntas, nos correspondentes catalisadores, melhoraram o desempenho catalítico, levando a altos valores de conversão e baixas taxas de deposição de coque. O teor de MgO ótimo foi de 20%mol no sistema NiO/MgO/ZrO2, e de 20% e 40% mol de Y2O3 no sistema NiO/Y2O3/ZrO2. Nos catalisadores NiO-MgO-ZrO2, a solução sólida NiO-MgO favoreceu principalmente a reação de reforma seca do metano (CH4+CO2), enquanto que nos catalisadores NiO-Y2O3-ZrO2 a solução sólida Y2O3-ZrO2 favoreceu principalmente à oxidação parcial do metano (CH4+1/2O2). Os catalisadores Ni20MZ e Ni20YZ apresentaram resultados promissores para a reforma oxidativa de biogás em presença de oxigênio sendo estes catalisadores melhores do que uma amostra comercial de Ni/Al2O3 (20%Ni) testada nas mesmas condições de reação. A razão H2/CO nos produtos das reações sobre os melhores catalisadores foi muito próxima de 1,0; o que permite seu uso direto em diversas reações, como reação de Fischer-Tropsch, síntese direta de dimetil-éter (processo STD) e síntese de formaldeído. / The anaerobic fermentation of the organic material produces a mixture of gases called biogas. This biogas contains CH4 and CO2 as major components. These two compounds are greenhouse gases and their use are very important from the environmental and economic point of view. The present study aimed to produce synthesis gas (H2/CO), a high-value raw material for the chemical industry, from the oxidative reforming of biogas using oxygen (1.5CH4 +1.0CO2+0.25O2) over NiO-MgO-ZrO2 and NiO-Y2O3-ZrO2 catalysts. These catalysts were prepared by the one-step polymerization method. The variation content of MgO and Y2O3 in each catalyst was studied. These materials were characterized by XRD, TPR, adsorption-desorption of N2, XPS, XAS, SEM and EDX; they were evaluated in the oxidative reforming reaction of a model biogas (molar composition: 1.5 CH4/1CO2) in the presence of oxygen at 750 &deg;C and 1atm, aiming to produce synthesis gas.<br /> The content of MgO in the NiO/MgO/ZrO2 system was varied ranging from 0-100% (0%, 4%, 20%, 40% and 100%mol in relation to ZrO2) , the same contents were used for the Y2O3 in the NiO/Y2O3/ZrO2 system. All catalysts had 20% wt of Ni. The XRD, TPR and XPS confirmed the formation of NiO-MgO and the MgO-ZrO2 solid solutions in the NiO-MgO-ZrO2 catalysts; and NiO-Y2O3 and Y2O3-ZrO2 solid solutions in the NiO-Y2O3-ZrO2 catalysts. These solid solutions together, in the corresponding catalysts, inproved the catalytic performance, leading to high conversion rates and low carbon deposition rates. The optimum MgO content was 20mol% for the NiO/MgO/ZrO2 system and 20% and 40mol% of Y2O3 for the NiO/Y2O3/ZrO2 system. In the NiO-MgO-ZrO2 catalysts, the NiO-MgO solid solution promoted primarily the dry reforming reaction of methane (CH4 + CO2), while in the NiO-Y2O3-ZrO2 catalysts, the Y2O3-ZrO2 solid solution primarily favored the partial oxidation of methane (CH4 + 1/2O2). The Ni20MZ and Ni20YZ catalysts showed promising results for the oxidative reforming of biogas in the presence of oxygen; these catalysts being better than a commercial catalysts (Ni/Al2O3; 20%wt Ni) tested under the same reaction conditions. The H2/CO ratio in the reaction products over the best catalysts was very close to 1.0, which allows its direct use in various processes such as Fischer-Tropsch process, Syngas-to-dimethyl-ether process (STD) and in the synthesis of formaldehyde.

A tecnologia Coal, Gas or Biomass-To-Liquids (XTL) permite a obtenção de combustíveis líquidos a partir de biomassa, carvão mineral ou gás natural. A síntese de catalisadores otimizados constitui um desafio para aumentar a viabilidade desses processos. Neste contexto, por exibirem propriedades catalíticas interessantes para diferentes processos químicos, os óxidos mistos apresentam-se como alternativas promissoras. Entretanto, a sua aplicação nesta tecnologia ainda requer maior investigação. A proposta da tese foi a de avaliar catalisadores baseados em óxidos mistos para a geração de gás de síntese a partir da decomposição do etanol e da reforma do etanol ou do metano. Foram preparadas amostras Fe-Al, Co-Al e Ni-Al pelo método da co-precipitação, sendo caracterizadas por diferentes técnicas. As reações foram conduzidas em reatores tubulares de leito fixo, com alimentação contínua dos reagentes gasosos e líquidos e com análise por cromatografia gasosa. Um melhor compromisso entre propriedades e desempenho catalítico na reação de decomposição do etanol foi observado para amostras com razões molares Ni2+/Al3+ entre 1 e 3, pois esta composição favoreceu a formação dos óxidos mistos. Para materiais baseados em Fe, Co ou Ni, houve a formação de materiais do tipo hidrotalcita nos precursores dos catalisadores Co-Al e Ni-Al, formando óxidos mistos após o tratamento térmico. Foram observadas conversões de etanol e seletividade para H2 e CO mais altas na reação de decomposição do etanol sobre estas amostras. Catalisadores à base de ferro conduziram à maior formação de eteno e acetaldeído e menor deposição de coque. A substituição parcial de Ni por um terceiro elemento modificou o perfil de redução e diminuiu a acidez das amostras. Nas amostras Ni-Al, os catalisadores contendo Zn, Mo ou Co apresentaram maior atividade na reação de reforma a vapor do etanol nas temperaturas de 400 e 450°C. Um aumento na redutibilidade e na área específica foi verificado com a substituição parcial de ferro por cobre ou cobalto nas amostras Fe-Al. A melhoria nas propriedades do material resultou em desempenho superior nos testes de reforma a vapor do etanol, especialmente para o catalisador Co-Fe-Al. Em relação à reforma do metano, foram investigadas amostras Co-Al modificadas com um terceiro elemento. A substituição parcial de Co por um elemento de maior alcalinidade propiciou um incremento na área específica e modificações no perfil de redução, na força ou quantidade de sítios alcalinos e na cristalinidade do material. As alterações nas propriedades do material proporcionaram menor formação de coque, sendo mantidas ou elevadas as conversões de CH4 e CO2. O catalisador Mg-Co-Al apresentou os melhores resultados de atividade, especialmente para o catalisador com razão molar Mg/Co = 0,5 e para ativação na temperatura de 500°C. Desta forma, foi possível avaliar as diferenças entre óxidos mistos contendo diferentes metais ativos para a geração do gás de síntese, bem como a otimização destes catalisadores por meio da adição de promotores. Os óxidos mistos exibiram alta área específica, elevada estabilidade térmica e moderada acidez que conduziram a melhores desempenhos nos diferentes processos estudados. / The Coal or Gas or Biomass-To-Liquids (XTL) technology allows the production of liquid fuels from biomass, mineral coal or natural gas. The synthesis of optimized catalysts is a great challenge for improving the feasibility of these processes. In this context, mixed oxides are promising alternatives as they exhibit interesting catalytic properties for different chemical processes. However, its application for XTL processes still requires further investigation. The purpose of this thesis was to evaluate catalysts based on mixed oxides for the generation of synthesis gas through the decomposition of ethanol and the reforming of ethanol or methane. Fe-Al, Co-Al and Ni-Al samples were prepared by the co-precipitation method and characterized by different techniques. The reactions were conducted using tubular fixed bed reactors. The gaseous and liquid feedstocks were fed continuously and the analysis was performed by gas chromatography. A better commitment between the properties and catalytic performance for the decomposition of ethanol was observed for samples with Ni2+/Al3+ molar ratios between 1 and 3 because this composition favored the formation of the mixed oxides. For the Fe-, Coor Ni-based materials, the formation of hydrotalcite-type materials was identified in the precursors of the Co-Al and Ni-Al catalysts and thus yielding mixed oxides after thermal treatment. Higher conversion of ethanol and selectivity towards H2 and CO for the decomposition of ethanol was observed for these samples. The iron-based catalysts led to higher formation of ethylene and acetaldehyde and a decrease on the coke deposition. The partial substitution of Ni by a third element modified the reduction profile and decreased the acidity of samples. For the Ni-Al samples, the catalysts containing Zn, Mo or Co showed higher activity for the steam reforming of ethanol at 400 and 450°C. An increase in the reducibility and in the specific surface area was verified when iron is partly substituted by copper or cobalt in the Fe-Al samples. The improvement in the properties of the material resulted in a better performance for the steam reforming of ethanol, especially for the Co-Fe-Al catalyst. Regarding the reforming of methane, different Co-Al samples modified with a third element were investigated. The partial substitution of Co by an element with higher basicity provided an increase in the specific surface area and modifications on the reduction profile, in the strength or quantity of the alkalinity sites and in the overall crystallinity of the material. The changes in the properties provided smaller coke formation while maintaining or even increasing the CO2 and CH4 conversions. The Mg-Co-Al catalyst exhibited the best activity results, especially for the catalyst with Mg/Co molar ratio of 0.5 and for activation at 500°C. Therefore, it was possible to evaluate the differences between the mixed oxides based on different active metals for the generation of the synthesis gas, as well as the optimization of these catalysts through the addition of promoters. The mixed oxides exhibited high specific surface area, high thermal stability and moderate acidity that led to better performance for the different studied processes.

A tecnologia Coal, Gas or Biomass-To-Liquids (XTL) permite a obtenção de combustíveis líquidos a partir de biomassa, carvão mineral ou gás natural. A síntese de catalisadores otimizados constitui um desafio para aumentar a viabilidade desses processos. Neste contexto, por exibirem propriedades catalíticas interessantes para diferentes processos químicos, os óxidos mistos apresentam-se como alternativas promissoras. Entretanto, a sua aplicação nesta tecnologia ainda requer maior investigação. A proposta da tese foi a de avaliar catalisadores baseados em óxidos mistos para a geração de gás de síntese a partir da decomposição do etanol e da reforma do etanol ou do metano. Foram preparadas amostras Fe-Al, Co-Al e Ni-Al pelo método da co-precipitação, sendo caracterizadas por diferentes técnicas. As reações foram conduzidas em reatores tubulares de leito fixo, com alimentação contínua dos reagentes gasosos e líquidos e com análise por cromatografia gasosa. Um melhor compromisso entre propriedades e desempenho catalítico na reação de decomposição do etanol foi observado para amostras com razões molares Ni2+/Al3+ entre 1 e 3, pois esta composição favoreceu a formação dos óxidos mistos. Para materiais baseados em Fe, Co ou Ni, houve a formação de materiais do tipo hidrotalcita nos precursores dos catalisadores Co-Al e Ni-Al, formando óxidos mistos após o tratamento térmico. Foram observadas conversões de etanol e seletividade para H2 e CO mais altas na reação de decomposição do etanol sobre estas amostras. Catalisadores à base de ferro conduziram à maior formação de eteno e acetaldeído e menor deposição de coque. A substituição parcial de Ni por um terceiro elemento modificou o perfil de redução e diminuiu a acidez das amostras. Nas amostras Ni-Al, os catalisadores contendo Zn, Mo ou Co apresentaram maior atividade na reação de reforma a vapor do etanol nas temperaturas de 400 e 450°C. Um aumento na redutibilidade e na área específica foi verificado com a substituição parcial de ferro por cobre ou cobalto nas amostras Fe-Al. A melhoria nas propriedades do material resultou em desempenho superior nos testes de reforma a vapor do etanol, especialmente para o catalisador Co-Fe-Al. Em relação à reforma do metano, foram investigadas amostras Co-Al modificadas com um terceiro elemento. A substituição parcial de Co por um elemento de maior alcalinidade propiciou um incremento na área específica e modificações no perfil de redução, na força ou quantidade de sítios alcalinos e na cristalinidade do material. As alterações nas propriedades do material proporcionaram menor formação de coque, sendo mantidas ou elevadas as conversões de CH4 e CO2. O catalisador Mg-Co-Al apresentou os melhores resultados de atividade, especialmente para o catalisador com razão molar Mg/Co = 0,5 e para ativação na temperatura de 500°C. Desta forma, foi possível avaliar as diferenças entre óxidos mistos contendo diferentes metais ativos para a geração do gás de síntese, bem como a otimização destes catalisadores por meio da adição de promotores. Os óxidos mistos exibiram alta área específica, elevada estabilidade térmica e moderada acidez que conduziram a melhores desempenhos nos diferentes processos estudados. / The Coal or Gas or Biomass-To-Liquids (XTL) technology allows the production of liquid fuels from biomass, mineral coal or natural gas. The synthesis of optimized catalysts is a great challenge for improving the feasibility of these processes. In this context, mixed oxides are promising alternatives as they exhibit interesting catalytic properties for different chemical processes. However, its application for XTL processes still requires further investigation. The purpose of this thesis was to evaluate catalysts based on mixed oxides for the generation of synthesis gas through the decomposition of ethanol and the reforming of ethanol or methane. Fe-Al, Co-Al and Ni-Al samples were prepared by the co-precipitation method and characterized by different techniques. The reactions were conducted using tubular fixed bed reactors. The gaseous and liquid feedstocks were fed continuously and the analysis was performed by gas chromatography. A better commitment between the properties and catalytic performance for the decomposition of ethanol was observed for samples with Ni2+/Al3+ molar ratios between 1 and 3 because this composition favored the formation of the mixed oxides. For the Fe-, Coor Ni-based materials, the formation of hydrotalcite-type materials was identified in the precursors of the Co-Al and Ni-Al catalysts and thus yielding mixed oxides after thermal treatment. Higher conversion of ethanol and selectivity towards H2 and CO for the decomposition of ethanol was observed for these samples. The iron-based catalysts led to higher formation of ethylene and acetaldehyde and a decrease on the coke deposition. The partial substitution of Ni by a third element modified the reduction profile and decreased the acidity of samples. For the Ni-Al samples, the catalysts containing Zn, Mo or Co showed higher activity for the steam reforming of ethanol at 400 and 450°C. An increase in the reducibility and in the specific surface area was verified when iron is partly substituted by copper or cobalt in the Fe-Al samples. The improvement in the properties of the material resulted in a better performance for the steam reforming of ethanol, especially for the Co-Fe-Al catalyst. Regarding the reforming of methane, different Co-Al samples modified with a third element were investigated. The partial substitution of Co by an element with higher basicity provided an increase in the specific surface area and modifications on the reduction profile, in the strength or quantity of the alkalinity sites and in the overall crystallinity of the material. The changes in the properties provided smaller coke formation while maintaining or even increasing the CO2 and CH4 conversions. The Mg-Co-Al catalyst exhibited the best activity results, especially for the catalyst with Mg/Co molar ratio of 0.5 and for activation at 500°C. Therefore, it was possible to evaluate the differences between the mixed oxides based on different active metals for the generation of the synthesis gas, as well as the optimization of these catalysts through the addition of promoters. The mixed oxides exhibited high specific surface area, high thermal stability and moderate acidity that led to better performance for the different studied processes.