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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Adsorption Separation of CO2 from CO in Syngas: Improving the Conversion of the Reverse Water Gas Shift Reaction

Wilson, Sean M. W. January 2015 (has links)
In this research project, adsorption is considered for the separation of CO2 from CO for applications such as industrial syngas production and in particular to improve the conversion of the Reverse Water Gas Shift (RWGS) process. The use of adsorption technology for these applications requires an adsorbent that can effectively separate out CO2 from a gas mixture containing CO2, CO, and H2. However, adsorption of H2 is insignificant when compared to both CO2 and CO, with only CO2 and CO being the adsorbed species. The adsorption of CO2 and CO was investigated in this work for four major types of industrial adsorbents which include: activated aluminas, activated carbons, silica gels, and zeolites. Zeolites, with their ability to be fine tuned many parameters which may affect adsorption, were investigated in terms of the effect of the cations present, SiO2/Al2O3 ratios, and structure to determine how to optimize adsorption of CO2 while decreasing adsorption of CO. This will help to determine a promising adsorbent for this separation with focus on maximizing the selective adsorption of CO2 over CO. To investigate this separation three scientific experimental methods were used; gravimetric adsorption isotherm analysis, volumetric adsorption isotherm analysis, and packed bed adsorption desorption breakthrough analysis. Gravimetric and volumetric methods allow for testing the adsorbent with the individual species of CO2 and CO. This investigation will let us determine the pure component adsorption capacity, heats of adsorption, regenerability, and basic selectivity. Packed bed adsorption breakthrough experimentation was then carried out on promising adsorbents for the CO2 separation from a mixture of CO2, CO, and H2. These experiments used a gas mixture that would be comparable to that produced from the RWGS reaction to determine the multicomponent gas mixture behaviour for adsorption. Temperature swing adsorption (TSA) with a purge gas stream of H2 was then used to regenerate the adsorbent.
82

Estudo da pirólise do bio-óleo / Study of bio-oil pyrolysis

Costa, Lucas Ferrari de Carvalho, 1989- 24 August 2018 (has links)
Orientador: Caio Glauco Sánchez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-24T08:46:37Z (GMT). No. of bitstreams: 1 Costa_LucasFerrarideCarvalho_M.pdf: 3999968 bytes, checksum: 7756a52a0e0727ae5b7f9d138e57ef02 (MD5) Previous issue date: 2013 / Resumo: A pirólise rápida é um processo aplicado a biomassa com o intuito de densifica-la energeticamente, os produtos resultantes são, gases, carvão e principalmente bio-óleo. O bio-óleo pode servir como matéria prima para as biorrefinarias e pode ser transformado em gás de síntese através da degradação térmica a altas temperaturas com a presença ou não de agente oxidante externo, gaseificação e pirólise respectivamente. Durante estes processos podem ocorrer reações de polimerização formando coque no interior do reator. O processo de formação de coque ainda é pouco conhecido. O coque pode entupir o reator e/ou desativar catalizadores que estejam no processo. Tem-se como objetivo neste trabalho estudar a pirólise do bio-óleo e diminuir a formação de coque na reação através da destilação prévia do composto a uma temperatura de 260 ºC, pois a partir desta temperatura não ocorre mais a formação de vapores. As amostras da pirólise a 700 ºC em um reator de fluxo arrastado do bio-óleo integral (BPL) e do bio-óleo destilado (BPLD) foram comparadas com testes estatístico t-student em relação a formação de coque, balanço de massas, composição gasosa e poder calorífico do gás produzido. O resultado da pirólise dos bio-óleos foi a não formação de coque no interior do reator quando utilizado o BPLD. O gás resultante da pirólise do BPLD teve um poder colorífico inferior (PCI) de 8,3 ± 0,6 MJ/Nm3, e o gás resultante da pirólise do BPL teve um PCI = 6,1 ± 0,7 MJ/Nm3. O balanço de massas indicou que a formação de gases é estatisticamente igual nos dois processos para um significância ? = 5%. Assim é possível afirmar que a produção de coque foi nula para a pirólise do BPLD. A quantidade de gás gerada pelos processos foi equivalente e o poder calorifico do gás resultante do BPLD é maior que o gás resultante da pirólise do BPL / Abstract: The fast pyrolysis is a process applied to densifies the biomass, the resulting products are gas, char and mainly bio-oil. The bio-oil can serve as raw material for bio-refineries and can be transformed into syngas by thermal degradation at high temperatures with the presence of oxidizing agent, in a process called gasification, or without external oxidizing agent, in a process called pyrolysis. During these processes, polymerization reactions can occur forming coke inside the reactor. The formation of coke is a process still unknown. The coke can clog the reactor and/or disable catalysts of the process. Study the pyrolysis of the bio-oil and reduce the formation of coke through the distillation of the bio-oil at temperatures above 260 ºC is the objective of this work. Samples from pyrolysis at 700 ° C in an entrained flow reactor of full bio-oil (BPL) and the bio-oil distillate (BPLD) were compared with t-student statistical tests for coke formation, mass balance, composition of gas and gas calorific value. The result of pyrolysis of the bio-oils was no coking within the reactor when using the BPLD. The lower heat value (LHV) of the gas resulting from pyrolysis of BPLD was 8,3 ± 0,6 MJ/Nm3, and the gas resulting from the pyrolysis of BPL was 6,1 ± 0,7 MJ/Nm3. The mass balance indicated that gas formation is statistically equal in the two cases for a significance level ? = 5 %. It is possible to affirm that the production of coke was null for the pyrolysis of BPLD. The amount of gas generated by the process was equivalent and the heat value of the gas resulting from the pyrolysis of BPLD is greater than the gas resulting from pyrolysis of BPL / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica
83

Desenvolvimento de microrreatores para produção de hidrogênio e gás de síntese a partir da reação de pirólise da glicerina aplicando laser de CO2 / Development microreactos for hydrogen and syngas production from glycerol pyrolysis by CO2 laser

Peres, Ana Paula Gimenez, 1985- 12 February 2014 (has links)
Orientadores: Rubens Maciel Filho, André Luiz Jardini Munhoz, Betânia Hoss Lunelli / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T10:23:37Z (GMT). No. of bitstreams: 1 Peres_AnaPaulaGimenez_D.pdf: 3966242 bytes, checksum: a5d9efcc4a345b82183bab53e34a3ebd (MD5) Previous issue date: 2014 / Resumo: Dentre as rotas alternativas e novas fontes sustentáveis de energia, a biomassa vem se tornando uma opção com potencial para atender a crescente demanda por energia e combustíveis. Como exemplo de fonte renovável, podemos citar o biodiesel, uma das fontes de energia limpa e alternativa mais promissora, cuja produção mundial vem crescendo anualmente. Neste contexto, a geração de hidrogênio e gás de síntese a partir da glicerina bruta tem sido considerada. O principal objetivo desta Tese foi projetar, fabricar e testar um microrreator para produção de hidrogênio a partir da pirólise da glicerina utilizando Laser de CO2 como fonte de energia. Para o cumprimento deste objetivo, quatro etapas principais foram desenvolvidas. A primeira delas foi a realização de estudos fluidodinâmicos do microrreator para a escolha da geometria mais favorável à distribuição do fluxo entre os microcanais. Nesta etapa foi possível quantificar o fluxo do gás nos microcanais e escolher a geometria de acordo com o menor valor no desvio padrão relativo apresentado pela geometria do microrreator. Contudo, neste trabalho, o modelo de microrreator com microcanais internos apresentado não será aplicado, pois de acordo com o objetivo principal da Tese - produção de hidrogênio e gás de síntese a partir da pirólise da glicerina aplicando o laser de CO2 - a radiação do laser deverá atingir diretamente a superfície da amostra (glicerina). Na segunda etapa, através da tecnologia de prototipagem rápida/impressão 3D foi fabricado o protótipo do microrreator e a partir desse protótipo foi fabricado o microrreator a partir do método convencional de usinagem. Na terceira etapa, os parâmetros do laser de CO2, tais como potência, velocidade de varredura e tempo de incidência foram avaliados, através de simulações computacionais. A partir da variável de resposta - geração de calor na amostra - foi possível identificar que a potência do laser de CO2 é a variável com maior influência na geração de calor. Na etapa final, experimentos de pirólise da glicerina foram realizados no microrreator com laser de CO2. Os resultados mostraram significantes conversões para a produção de hidrogênio e gás de síntese. A potência do laser de CO2 foi a variável operacional mais importante. Uma conversão na faixa de 54 a 66 % foi obtida quando uma potência de 60 W foi aplicada / Abstract : Motivated to solve the problems caused by the use of non-renewable fuels, scientists around the world seek ways to develop renewable energy that can reduce these impacts in Earth's atmosphere. Among the alternative routes and new sustainable energy sources, biomass is becoming a potential with option to meet the growing demand for energy and fuel. As a renewable source of one example, biodiesel, one of the sources of clean energy and more promising alternative, whose world production is increasing annually. In this context, the generation of hydrogen and syngas from crude glycerol has been considered. Therefore, the objective of this thesis was to design, fabricate and test a microreactor for hydrogen production from glycerol pyrolysis using CO2 laser as a source of energy. To achieve this objective, four main steps were developed. Firstly, studies of the fluid dynamic behavior of microreactor was conducted for choosing the most favorable geometry to flow distribution among microchannels. At this point it was possible to quantify the internal gas flow in the microchannels and to select the geometry with the lowest value in the relative standard deviation. However, in this thesis, the model of microreactor with internal microchannels presented will not be applied, because according to the main objective of the thesis - the production of hydrogen and synthesis gas from pyrolysis of the glycerol applying the CO2 laser - laser radiation should directly reach the surface of the sample (glycerol). In the second step, by rapid prototyping technology/3D printing was made the microreactor of the prototype and from the prototype that was manufactured the microreactor from conventional machining method. In the third step, the CO2 laser parameters such as power, sweep rate and incidence of time were evaluated through computer simulations. From the response variable - heat generation in the sample - we found that the power of the CO2 laser is the variable with the greatest influence on the generation of heat. In the final step, glycerol pyrolysis experiments were performed in the microreactor with CO2 laser. The results showed significant conversions for the production of hydrogen and synthesis gas. The power of the CO2 laser is the most important operational variable. A conversion in the range 54-66% was obtained when an output of 60 W was applied / Doutorado / Engenharia Química / Doutora em Engenharia Quimica
84

Projeto conceitual simulação e análise de plantas de produção de etanol a partir do gás de síntese / Conceptual projetct, simulation and analysis of ethanol production plants from syngas

Miranda, Júlio César de Carvalho, 1983- 28 August 2018 (has links)
Orientadores: Maria Regina Wolf Maciel, Rubens Maciel Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-28T02:11:55Z (GMT). No. of bitstreams: 1 Miranda_JulioCesardeCarvalho_D.pdf: 11420052 bytes, checksum: 1d66d50744b41020ecf572a3b96b2561 (MD5) Previous issue date: 2015 / Resumo: O gás de síntese (syngas) é conhecido principalmente pelo seu uso na produção de amônia (Processo Harber-Bosch) e hidrocarbonetos (Processo Fischer-Tropsch). No entano, uma rota menos explorada para a produção de produtos químicos, entre eles alcoóis e outros oxigenados, a partir do gás de síntese, vem ganhando atenção nos últimos anos. Nessa rota, a matéria-prima inicial, como a biomassa é inicialmente gaseificada ao syngas, o qual é reformado, limpo, comprimido e finalmente convertido cataliticamente em uma mistura de alcoóis e produtos oxigenados que, após os passos de separação, atingem a pureza necessária para sua comercialização. Nesse trabalho, a rota termoquímica, como é conhecida, é utilizada com o objetivo de se produzir etanol a partir do syngas. Utilizando o simulador comercial ASPEN Plus v7.3, foram propostos 9 casos de estudo utilizando 3 categorias diferentes de catalisador em 4 diferentes layouts de processo. Todos os casos de estudo foram avaliados quanto à sua produtividade, ao seu consumo de energia e aspectos de importância econômica. Foi possível concluir a partir das análises feitas que cada uma das categorias de catalisador possui vantagens e desvantagens dependendo do contexto econômico, podendo-se citar a diferenciada produção de hidrocarbonetos e outros oxigenados além do etanol, a geração de água, o número de unidades de separação e o consumo de energia / Abstract: Synthesis gas (syngas) is mostly known by its use on ammonia (Harber-Bosch process) and hydrocarbons (Fischer-Tropsch process) production processes. However, a less explored route to produce chemical products, among them alcohols and other oxygenates, from syngas is gaining attention over the last few years. In this route, an initial feedstock as biomass is firstly gasified to synthesis gas, which is reformed, cleaned, compressed and finally catalytically converted in a mixture of alcohols and oxygenated products that after separation steps attain sufficient purity to be sold. In this work, the thermochemical route, as it is known, is used aiming ethanol production from syngas. Using the commercial simulator ASPEN Plus v7.3, 9 case studies were proposed using 3 different categories of catalysts in 4 different process layouts. All the cases were evaluated regarding their productivity, their energy consumption, and aspects of economic importance. It was possible to conclude from the analysis that each of the catalyst categories has advantages and disadvantages depending on the economic context, among them the different proportion of hydrocarbons and other oxygenated products besides ethanol, water generation, number of separation unities and energy consumption / Doutorado / Engenharia Química / Doutor em Engenharia Química
85

Supercritical Water Gasification of Two-Carbon Carboxylic Acid Derivatives

Conley, Matthew January 2018 (has links)
No description available.
86

Syngas and Hydrogen Production Enhancement Strategies in Chemical Looping Systems

Nadgouda, Sourabh Gangadhar January 2019 (has links)
No description available.
87

Catalytic Modification of Oxygen Carriers for Chemical Looping Applications

Guo, Mengqing January 2019 (has links)
No description available.
88

Production of Hydrocarbons from Gasified Biomass Using Bifunctional Catalysts

Street, Jason Tyler 15 August 2014 (has links)
The following chapters deal with the chemistry, catalytic poisoning, newer catalyst technologies, and possible future solutions to increase the efficiency of creating high-value products by thermochemically converting gasified biomass (producer gas). Chapter 1 puts emphasis on multifunctional catalysts containing transition metals that are used for renewable fuel production. High-value products such as gasoline-range hydrocarbons, dimethyl ether (DME), aldehydes, isobutane, isobutene and other olefins can be produced with gasified biomass due to the gas containing syngas (H2 + CO). The chemistry and production of these chemicals is discussed in the review. Chapter 2 describes the reactor design of a bench scale system and results after using a Mo/HZSM- 5 catalyst for aromatic hydrocarbon creation. This chapter also discusses issues that came with trying to control the temperature without any reactor intercooling. Chapter 3 shows the feasibility of using a particular multifunctional catalyst with a lab scale system and also shows the importance of certain process variables including temperature, space velocity, gas ratios, and pressure. The subject of the importance of the cleanliness of the producer gas is also discussed so that maximum high-value product yield can be achieved with the greatest efficiency. Chapter 4 discusses the implementation of a bench scale and pilot scale reactor design (both with intercooling) and the results of scale-up when using the catalyst mentioned in Chapter 3. Chapter 5 involves the modelling of an industrialized system with Aspen Plus. The economics of industrial plants to produce hydrocarbons from coal or wood feedstocks at scales of 5, 50 and 5000 tons per day were modeled using CAPCOST.
89

Dry Reforming of Methane to Produce Syngas over Ni-Based Bimodal Pore Catalysts

Bao, Zhenghong 08 December 2017 (has links)
Dry reforming of methane is an important reaction to generate syngas from two greenhouse gases. The syngas can be used in Fishcher-Tropsch synthesis to produce valueded chemicals. Chapter I reviews the catalytic conversion of methane and carbon dioxide to syngas, including DRM reaction chemistry, catalysts used in this process, catalyst deactivation, and the kinetics of DRM reaction. Chapter II discusses the development of bimodal pore NiCeMgAl catalysts for DRM reaction. Bimodal pore NiCeMgAl catalysts were synthesized via the refluxed co-precipitation method and systematically investigated the influence of active metal loading, calcination temperature, reduction temperature and gas hourly space velocity (GHSV) on the catalytic performance of DRM reaction. The Ni15CeMgAl sample with 15 wt% NiO loading was found to be active enough at 750 °C with a high CH4 conversion of 96.5%. The proper reduction temperature for the NiCeMgAl catalyst is either 550–650 °C or 850 °C. Higher calcination temperature favors the formation of NiAl2O4 and MgAl2O4 spinel structures. Compared with non-bimodal pore NiCeMgAl catalyst, bimodal pore NiCeMgAl catalyst has a longer stability in the feed gas without dilution. In chapter III, the kinetic behavior of bimodal pore NiCeMgAl catalyst for DRM reaction was investigated after the elimination of external and internal diffusion effects in a fixed-bed reactor as a function of temperature and partial pressures of reactants and products. A Langmuir-Hinshelwood model was developed assuming that the carbon deposition is ignorable but the RWGS reaction is non-ignorable and the removal of adsorbed carbon intermediate is the rate-determining step. A nonlinear least-square method was applied to solve the kinetic parameters. The derived kinetic expression fits the experimental data very well with a R2 above 0.97, and predicts the products flow rate satisfactorily. Chapter IV documents the results of in situ XRD study on the NiMgAl catalyst for DRM reaction. The phase evolution of a NiMgAl oxide catalyst at the reduction stage was qualitatively analysed and quantitatively determined by employing the continuous changes in XRD intensity and TPR information. The stable crystallite size of both active metal and spinel support is responsible for the long stability of NiMgAl catalyst without carbon deposition during the DRM reaction.
90

Economic Evaluation of Biofuel Production through Bio-Gasification Power Facility using Modeling Method

Deng, Yangyang 11 August 2012 (has links)
Since bio-gasification is a potentially more efficient way to utilize bio-energy, the economic feasibility becomes one of the greatest issues when we apply this new technology. Evaluation of economic feasibility of a bio-gasification facility needs understanding of its production unit cost under different capacities and different working shift modes. The objectives of this study were to evaluate the unit cost of bio-syngas and biouel products at different capacities by using economic modeling method. Result showed that economic feasibility of a power facility was significantly affected by its production capacity and operating mode (one shift, two shifts, or three shifts mode). Economic feasibility could be improved by increasing production capacity or by changing operating mode to two or three shifts from one shift. The economic evaluation model and cost analysis software developed in this study could be a good tool for economic analysis of bio-syngasand biouel products from biomass gasification.

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