Partial oxidation of CH4, CO2 reforming of CH4, and oxidative CO2 reforming of CH4 to produce synthesis gas at 700°C over supported Ni catalysts have been studied. A Ni/Mg-Al catalyst was prepared by the solid phase crystallization (spc-) method starting from a hydrotalcite-type (HT) anionic precursor. From XRD analysis, only Ni0.5Mg2.5Al catalyst consists of the layered hydrotalcite-type structure; not Ni0.5Ca2.5Al and Ni/Al2O3 catalysts. By TPR test, the Ni0.5Mg2.5Al-HT catalyst requires a high reduction temperature than the Ni0.5Ca2.5Al catalyst. It implies that the Ni0.5Mg2.5Al-HT which has a layered structure shows the stronger interaction strength between the molecules. It might increase the resistance of coke formation on the surface of the catalyst. For the reaction tests, the Ni0.5Ca2.5Al showed the highest initial activity for synthesis gas production for all reactions; but, its activity was decreased quickly due to coke formation except during the partial oxidation of CH4. The Ni0.5Mg2.5Al-HT showed a relatively higher reactivity compared to the equilibrium level than Ni/Al2O3 catalyst; and it shows very stable reactivity than other catalysts. By TPO test, the Ni0.5Mg2.5Al-HT has the lower amount of coke formed during the reaction than the Ni0.5Ca2.5Al catalyst. It confirms that the Ni0.5Mg2.5Al-HT catalyst has stronger resistance to coke formation; and it leads to provide stable reactivity in any reforming conditions at high temperature. Therefore, the Ni0.5Mg2.5Al-HT catalyst was the most promising catalyst in terms of activity and stability for partial oxidation, CO2 reforming, and oxidative CO2 reforming of CH4. The Ni0.5Mg2.5Al-HT catalyst was used to investigate the CO2 reforming of CH4 kinetics. With increasing CH4 partial pressures at constant CO2 partial pressure, the rates of CH4 consumption were increased. However, with increasing CO2 partial pressure at constant CH4 partial pressure, CH4 consumption rates was increased at lower CO2 partial pressure, but turned to independent at higher CO2 partial pressure. When the partial pressure of H2 was increased, the CO formation rate was decreased; it confirmed that the reverse water-gas shift (RWGS) reaction was occurring during the CO2 reforming of CH4 reaction. In addition, the reaction kinetic expression was proposed when the CH4 dissociation step was considered as a rate-limiting step.

In 2004 the Department of Chemical and Process Engineering (CAPE) at University of Canterbury began a programme to investigate using biomass gasification integrated combined cycle (BIGCC) technology to convert waste products and residues to useful energy for the wood processing sector. This research was conducted as a part of Objective Two of the programme to develop gasification and gas cleaning technology. This project involved commissioning and characterising the operation of the Fast Internal Circulating Fluidised Bed (FICFB) gasifier and comparing its operation with a more conventional up-draught process owned and operated by Page Macrae in Mount Manganui. The wood derived gas composition of each gasifier was measured using gas chromatography and these compositions were used to calculate lower heating values (LHV). The CAPE FICFB gasifier has proven to produce successfully a gas with a lower heating value of 10400-12500 kJ/Nm³. The Page Macrae gasification process produces a low quality gas with a lower heating value of 4100-5100 kJ/Nm³. This is much lower than the CAPE gasifier since the oxidant used in the up-draught gasification process is air and the product gas is diluted by nitrogen. The Page Macrae gasification system combusts wood derived gas to produce steam for a laminar veneer lumber (LVL) processing plant so gas quality and heating value are less important than in electrical production applications. Reducing the nitrogen content of the CAPE product gas will increase the heating value of the gas. Improvements to the boiler system will reduce the amount of air required for gasification and hence reduce the nitrogen content. Further improvements to gas quality can be gained from a change in the fuel feed point from on top of the gasification column's bubbling fluidised bed to the side of the bubbling fluidised bed. The CAPE gasifier is much more complicated and requires specialised operators but produces a gas suitable for gas engine and gas turbine technology. Overall the CAPE gasification system is more suited to BIGCC applications than the Page Macrae process.

Hydrogen is universally known as the most efficient renewable energy source capable of meeting global energy demands. Chlamydomonas reinhardtii has the ability to produce biohydrogen during the metabolic engineering of the photosynthetic pathways. The aim of this study was to 1) use leachate as a feedstock to enhance microalgal biomass and subsequent hydrogen production, 2) use Pulse Amplitude Modulated (PAM) Fluorometry to elucidate the role of photosystem one during hydrogen production, 3) use Nicotinamide Adenine Dinucleotide Phosphate (NADPH) fluorescence as an indicator of hydrogen production and 4) design a modular pilot scale biohydrogen bioprocessing system implementing experimental findings into a conceptual model. This resulted in a cost effective source of renewable hydrogen produced from waste. The use of 16% landfill leachate was found to increase biomass production by 26% as compared to using Tris- Acetate Phosphate (TAP) media alone. Hydrogen induction resulted in an increased gas synthesis of 37% as well as an increased production period of 8 days compared to the normal 5 days. Landfill leachate further reduced the costs as it acted as a free nutrient source with the added ecological advantage of leachate treatment. Hydrogen production was induced by sulphur depletion and physiological parameters were measured using PAM Fluorometry. Photosystem I was found to be dominant during hydrogen production while photosystem II was down-regulated due to the sulphur depletion and damaged D1 proteins. NADPH fluorescence was significantly correlated to hydrogen yields allowing for NADPH to be utilised as a molecular indicator for hydrogen synthesis. The overall functionality of this bioprocessing system relies on the optimum physiological functioning of cells. The above findings were implemented into a pilot scale design, maximising the physiological performance during hydrogen production. This study has contributed knowledge regarding the production of hydrogen gas from leachate, the physiological changes of photosystem I during hydrogen production and the use of NADPH fluorescence as an indicator. The fundamental theories of bioprocessing incorporate a firm understanding of cellular and biochemical processes. The use of molecular indicators determined from physiological studies can be used at pilot scale to improve overall efficiency of hydrogen production. / Ph.D. University of KwaZulu-Natal, Durban 2014.

Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Realff, Matthew; Committee Member: DeMartini, Nikolai; Committee Member: Muzzy, John; Committee Member: Sievers, Carsten.

Orientador: Carlos Alberto Luengo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-22T18:52:15Z (GMT). No. of bitstreams: 1 Filizola_AlexandreRodrigues_M.pdf: 3632264 bytes, checksum: 03e1e31881e49ad653e27f6ff8d6fc88 (MD5) Previous issue date: 2013 / Resumo: O objetivo deste trabalho é o desenvolvimento e a caracterização de nanocatalisadores ativos na catálise heterogênea da obtenção de gás de síntese a partir de bio-óleos. Com este fim pretende-se utilizar nanotubos de carbono NTC como suportes tridimensionais para os metais catalíticos. A amostra obtida pelo método de arco elétrico automatizado foi caracterizada utilizando-se as técnicas de espectroscopia Raman, medidas de área superficial (BET) e distribuição de tamanho de poro (BJH), difração de Raios-X, medidas de magnetização SQUID e microscopia de transmissão eletrônica TEM. Espera-se que estes nanocatalisadores diminuam a temperatura do processo de gaseificação dos bio-óleos / Abstract: The aim of this thesis is the development and characterization of nanocatalysts for the heterogeneous conversion of bio-oils into synthesis gas. To this end we intend to use carbon nanotubes (NTC) as unconventional supports for the catalytic transition metals. The sample obtained by a computer controlled electric arc method was characterized using the techniques of Raman spectroscopy, surface area measurement (BET) and pore size distribution (BJH), X-ray diffraction, SQUID magnetization measurements and transmission electron microscopy TEM. It is expected that these nanocatalysts would reduce the temperature of the gasification process of the bio-oil samples / Mestrado / Física / Mestre em Física

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.

Perovskita de LaFeO3 sintetizadas pelo método de Pechini foram avaliadas como catalisadores para a reação de oxidação parcial do metano. Foi impregnado níquel por via úmida como fase ativa em concentrações de 15 e 30 %, sobre as perovskitas, 15NLF e 30NLF, respectivamente, e o seu efeito foi avaliado para a mesma reação. Foi realizado análises termogravimétricas (TGA/DTGA) nos precursores da perovskitas, constatando a sua formação a 650 °C. A análise de microscopia de varredura (MEV) foi realizada nas amostras da perovskita pura, sendo que em uma delas foi realizada um banho de ultrassom para diminuir o tamanho de suas partículas e avaliar este efeito na reação de POM. Análises de difração de raio X (DRX) mostraram que todas as amostras apresentam as mesmas propriedades cristalográficas, sendo que, nas amostras contendo níquel, o metal apresentou-se na forma de NiO. O tamanho dos cristais, cálculado através da equação de Scherer, foi na ordem de 20 nm. Este resultado apontou que o níquel impregnado não participa da estrutura perovskita, mas sim está sobreposto a esta. Através da microscopia eletrônica de transmissão (TEM) foi possível visualizar a dispersão da fase ativa na superfície óxida e tamanhos de partículas na ordem de 20 nm. A redução a temperatura programada (TPR) apresentou as temperaturas de redução de espécies níquel e de ferro, presente na perovskita, e permitiu compreender a atuação das espécies Ni+2 e Fe0 na formação de H2 e CO. Os testes catalíticos foram realizados a 700ºC e 750°C, a pressão atmosférica, para uma vazão de alimentação de 200 cm3.min-1. Os testes cataliticos mostraram que a conversão de H2 dobrou para perovskita Ni/LaFeO3 em relação a LaFeO3. O catalisador 15NLF apresentou melhor estabilidade que o catalisador 30NLF para a reação. / LaFeO3 perovskite synthesized by the Pechini method were evaluated for the partial oxidation reaction of methane. Nickel was impregnated as the active phase in concentrations of 15 and 30%, on perovskites, 15NLF and 30NLF, respectively, and its effect was evaluated for the same reaction. Thermogravimetric analyzes (TGA / DTGA) were carried out on the perovskite precursors, confirming their formation at 650 °C. Scanning microscopy (SEM) was performed on pure perovskite samples, in one of them an ultrasonic bath was performed to reduce the size of its particles and to evaluate this effect in the POM reaction. X-ray diffraction (XRD) analyzes showed that all samples had the same crystallographic properties, and in the samples containing nickel, the metal was present as NiO. The size of the crystals, calculated through the Scherer equation, was in the order of 20 nm. This result pointed out that the impregnated nickel does not participate in the perovskite structure. Through transmission electron microscopy (TEM) it was possible to visualize the dispersion of the active phase on the oxide surface and particle sizes in the order of 20 nm. The programmed temperature reduction (TPR) showed the iron and nickel species reduction temperatures present in the perovskite, and allowed to understand the Ni+ 2 and Fe0 species in the H2 and CO formation. The catalytic tests were performed at 700 °C and 750 °C at atmospheric pressure for a flow rate of 200 cm3.min-1. The catalytic tests showed that the conversion of H2 doubled to perovskite Ni/LaFeO3 in relation to LaFeO3. 15NLF catalyst presented better stability than the 30NLF catalyst for the reaction.

The search for environmentally benign energy sources is becoming increasingly urgent. One such technology is fuel cells, e.g., the polymer electrolyte membrane (PEM) fuel cell which uses hydrogen as a fuel and emits only H2O. However, reforming hydrocarbon fuels to produce the needed hydrogen yields reformate streams containing CO2 as well as CO, which is toxic to the PEM fuel cell at concentrations above 100ppm. As the amount of CO permitted to reach the fuel cell increases, the performance of the PEM fuel cell decreases until it ultimately stops functioning. The water-gas-shift (WGS) reaction, CO + H2O <-> H2 + CO2, provides a method for extracting the energy from the toxic CO by converting it into usable H2 along with CO2 which can be tolerated by the fuel cell. Although a well established industrial process, alternate catalysts are sought for fuel cell application. Catalyst selection for the WGS reaction has, until recently, been based on trial-and-error screening of potential catalysts due to a lack of fundamental understanding of the catalyst's functioning. For this reason, we embarked on a deeper understanding of the molecular events involved in the WGS reaction such that a more systematic and theory-guided approach may be used to design and select catalysts more efficiently, i.e., rational catalyst design. The goal of this research was to develop a comprehensive predictive microkinetic model for the WGS reaction which is based solely on a detailed mechanism as well as theories of surface-molecule interactions (i.e., the transition-state theory) with energetic parameters determined a priori. This was followed by a comparison of the experimental results of sample catalysts to validate the model for various metal-based catalysts of interest including Cu, Fe, Ni, Pd, Pt, Rh, and Ru. A comprehensive mechanism of the plausible elementary reaction steps was compiled from existing mechanisms in the literature. These were supplemented with other likely candidates which are derivatives of those identified in the literature. Using established theories, we predicted the kinetics of each of the elementary reaction steps on metal catalysts of interest. The Unity Bond Index-Quadratic Exponential Potential Method (UBI-QEP) was used to predict the activation energies in both the forward and reverse direction of each step based solely on heats of chemisorption and bond dissociation energies of the species involved. The Transition State Theory (TST) was used to predict the pre-exponential factors for each step assuming an immobile transition state; however, the pre-exponential factors were adjusted slightly to ensure thermodynamic consistency with the overall WGS reaction. In addition, we have developed a new and powerful theoretical tool to gain further insight into the dominant pathways on a catalytic surface as reactants become products. Reaction Route (RR) Graph Theory incorporates fundamental elements of graph theory and electrical network theory to graphically depict and analyze reaction mechanisms. The stoichiometry of a mechanism determines the connectivity of the elementary reaction steps. Each elementary reaction step is viewed as a single branch with an assumed direction corresponding to the assumed forward direction of the elementary reaction step. The steps become interconnected via nodes which reflect the quasi-steady state conditions of the species represented by the node. A complete RR graph intertwines a series of routes by which the reactants may be converted to products. Once constructed, the RR graph may be converted into an electrical network by replacing, in the steady-state case, each elementary reaction step branch with a resistor and including the overall reaction as a power source where rate and affinity correspond to current and voltage, respectively. A simplification and reduction of the mechanism may be performed based on results from a rigorous De Donder affinity analysis as it correlates to Kirchhoff's Voltage Law (KVL), akin to thermodynamic consistency, coupled with quasi-steady state conditions, i.e., conservation of mass, analyzed using Kirchhoff's Current Law (KCL). Hence, given the elementary reaction step resistances, in conjunction with Kirchhoff's Laws, a systematic reduction of the network identifies the dominant routes, e.g., the routes with the lowest resistance, along with slow and quasi-equilibrium elementary reaction steps, yielding a simplified mechanism from which a predictive rate expression may possibly be derived. Here, we have applied RR Graph Theory to the WGS reaction. An 18-step mechanism was employed to understand and predict the kinetics of the WGS reaction. From the stoichiometric matrix for this mechanism, the topological features necessary to assemble the RR graph, namely the intermediate nodes, terminal nodes, empty reaction routes and full reaction routes, were enumerated and the graph constructed. The assembly of the RR graph provides a comprehensive overview of the mechanism. After reduction of the network, the simplified mechanism, comprising the dominant pathways, identified the quasi-equilibrium and rate-determining steps, which were used to determine the simplified rate expression which predicts the rate of the complete mechanism for different catalysts. Experimental investigations were conducted on the catalysts of interest to validate the microkinetic model derived. Comparison of the experimental results from the industrially employed catalysts (e.g., Cu, Ni, Fe, etc.) shows that the simplified microkinetic model sufficiently predicts the behavior of the WGS reaction for this series of catalysts with very good agreement. Other catalysis tested (Pt, Pd, Rh and Ru), however, had sufficient methanation activity that a direct comparison with WGS kinetics could not be made. In summary, we have developed a comprehensive approach to unravel the mechanism and kinetics of a catalytic reaction. The methodology described provides a more fundamental depiction of events on the surface of a catalyst paving the way for rational analysis and catalyst design. Illustrated here with the WGS reaction as an example, we show that the dominant RRs may be systematically determined through the application of rigorous fundamental constraints (e.g. thermodynamic consistency and mass conservation) yielding a corresponding explicit a priori rate expression which illustrates very good agreement not only with the complete microkinetic mechanism, but also the experimental data. Overall, RR graph theory is a powerful new tool that may become invaluable for unraveling the mechanism and kinetics of complex catalytic reactions via a common-sense approach based on fundamentals.

Perovskita de LaFeO3 sintetizadas pelo método de Pechini foram avaliadas como catalisadores para a reação de oxidação parcial do metano. Foi impregnado níquel por via úmida como fase ativa em concentrações de 15 e 30 %, sobre as perovskitas, 15NLF e 30NLF, respectivamente, e o seu efeito foi avaliado para a mesma reação. Foi realizado análises termogravimétricas (TGA/DTGA) nos precursores da perovskitas, constatando a sua formação a 650 °C. A análise de microscopia de varredura (MEV) foi realizada nas amostras da perovskita pura, sendo que em uma delas foi realizada um banho de ultrassom para diminuir o tamanho de suas partículas e avaliar este efeito na reação de POM. Análises de difração de raio X (DRX) mostraram que todas as amostras apresentam as mesmas propriedades cristalográficas, sendo que, nas amostras contendo níquel, o metal apresentou-se na forma de NiO. O tamanho dos cristais, cálculado através da equação de Scherer, foi na ordem de 20 nm. Este resultado apontou que o níquel impregnado não participa da estrutura perovskita, mas sim está sobreposto a esta. Através da microscopia eletrônica de transmissão (TEM) foi possível visualizar a dispersão da fase ativa na superfície óxida e tamanhos de partículas na ordem de 20 nm. A redução a temperatura programada (TPR) apresentou as temperaturas de redução de espécies níquel e de ferro, presente na perovskita, e permitiu compreender a atuação das espécies Ni+2 e Fe0 na formação de H2 e CO. Os testes catalíticos foram realizados a 700ºC e 750°C, a pressão atmosférica, para uma vazão de alimentação de 200 cm3.min-1. Os testes cataliticos mostraram que a conversão de H2 dobrou para perovskita Ni/LaFeO3 em relação a LaFeO3. O catalisador 15NLF apresentou melhor estabilidade que o catalisador 30NLF para a reação. / LaFeO3 perovskite synthesized by the Pechini method were evaluated for the partial oxidation reaction of methane. Nickel was impregnated as the active phase in concentrations of 15 and 30%, on perovskites, 15NLF and 30NLF, respectively, and its effect was evaluated for the same reaction. Thermogravimetric analyzes (TGA / DTGA) were carried out on the perovskite precursors, confirming their formation at 650 °C. Scanning microscopy (SEM) was performed on pure perovskite samples, in one of them an ultrasonic bath was performed to reduce the size of its particles and to evaluate this effect in the POM reaction. X-ray diffraction (XRD) analyzes showed that all samples had the same crystallographic properties, and in the samples containing nickel, the metal was present as NiO. The size of the crystals, calculated through the Scherer equation, was in the order of 20 nm. This result pointed out that the impregnated nickel does not participate in the perovskite structure. Through transmission electron microscopy (TEM) it was possible to visualize the dispersion of the active phase on the oxide surface and particle sizes in the order of 20 nm. The programmed temperature reduction (TPR) showed the iron and nickel species reduction temperatures present in the perovskite, and allowed to understand the Ni+ 2 and Fe0 species in the H2 and CO formation. The catalytic tests were performed at 700 °C and 750 °C at atmospheric pressure for a flow rate of 200 cm3.min-1. The catalytic tests showed that the conversion of H2 doubled to perovskite Ni/LaFeO3 in relation to LaFeO3. 15NLF catalyst presented better stability than the 30NLF catalyst for the reaction.

Made available in DSpace on 2017-07-10T15:14:47Z (GMT). No. of bitstreams: 1 Luiz Inacio Chaves.pdf: 1830089 bytes, checksum: 5146991baf6ffcd2929ea26b316d8b8d (MD5) Previous issue date: 2012-09-17 / The use of biomass as energy source is one of the most promising, because it contributes to reduce emissions of carbon dioxide in the atmosphere and allow the decentralized energy generation. Gasification is a technology of processing biomass energy into a gaseous biofuel of low calorific value. The gas can be used in Otto cycle engine for power generation in isolated communities. This study evaluated the capacity of the gasification gas in a fixed bed gasifier downtraft of two stages, the wood consumption, the efficiency of the gasifier and the gas consumption and efficiency in apower-generator Otto cycle. The gasifier use was a TERMOQUIP brand, model CD 40. The evaluated power-generator was a BRANCO brand, direct injection and power of 13 cv coupled to an electric generator of 5.5 cv. The gasification gas was injected into the engine mixed with the intake air. The generator was subjected to loads ranging from 0.5 kW to 2.5 kW, with the aid of a bank of electrical resistances. The production of gas from the gasifier and gas consumption by the motor were measured by means of a gasometer. The average gas production resulting from the gasification of wood presented during testing was 14.28 m³ h&#713; ¹. Wood consumption averaged 5.61 kg h&#713; ¹. The average yield of gas per unit weight was approximately 2.55 m3kg&#713; ¹. The gasification efficiency averaged 57.2%. When fed with synthesis gas, the output voltage of the generator was kept within the standards established by Companhia Paranaense de Energia (Copel, 2008), varying only between 221 and 223 V. For tests with the power-generator the best condition occurred for the highest load, 2.5 kW, where the gas consumption was about 10.6 m³ h&#713; ¹ and specific fuel consumption of 4.8 m³ kWh&#713;¹. For this condition, the average specific fuel consumption of equivalent wood was 1.9 kg kWh &#713; ¹ and the overall efficiency of power-generator was about 16.6%. / O uso da biomassa como fonte de energia é uma das formas mais promissoras, pois contribui para a redução das emissões de dióxido de carbono na atmosfera e possibilita a geração descentralizada de energia. A gaseificação é uma tecnologia de transformação energética da biomassa num biocombustível gasoso de baixo poder calorífico. O gás pode ser utilizado em motor ciclo Otto para geração de energia elétrica em comunidades isoladas. Este trabalho avaliou a capacidade de produção de gás de gaseificação em um gaseificador concorrente de leito fixo de dois estágios, o consumo de madeira, a eficiência do gaseificador, a eficiência e o consumo de gás num motor-gerador ciclo Otto. O gaseificador utilizado foi da marca TERMOQUIP, modelo CD 40. O motor-gerador avaliado foi da marca BRANCO, com injeção direta e potência de 13 cv acoplado a um gerador elétrico de 5,5 cv. O gás de gaseificação foi injetado no motor misturado com o ar de admissão. O gerador foi submetido a cargas que variaram entre 0,5 kW e 2,5 kW, com o auxílio de um banco de resistências elétricas. A produção de gás do gaseificador e o consumo de gás pelo motor foram medidos por meio de um gasômetro. A produção de gás média resultante da gaseificação de madeira apresentada durante os testes foi de 14,28 m³ h&#713;¹. O consumo de madeira apresentou uma média de 5,61 kg h&#713;¹. A média de rendimento de gás por unidade de massa foi de aproximadamente 2,55 m3 kg&#713;¹. A eficiência de gaseificação média foi de 57,2 %.Quando alimentado com gás de síntese, a tensão de saída do gerador se manteve dentro dos padrões estabelecidos pela Companhia Paranaense de Energia (COPEL, 2008), variando somente entre 221 e 223 V. Em relação aos testes com o motor-gerador, a melhor condição ocorreu para a maior carga, 2,5 kW, onde o consumo de gás foi cerca de 10,6 m³ h&#713;¹ e o consumo específico de combustível de 4,8 m³ kWh&#713;¹. Para essa condição, a média de consumo específico equivalente de madeira foi de 1,9 kg kWh&#713;¹e a eficiência global do motor-gerador foi de 16,6 %.