Catalytic Steam Reforming Of Ethanol For Hydrogen Production: Brief Status

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Hydrogen represents a promising fuel since it is considered as a dean energy carrier and also because during its combustion only water is emitted. It can be produced from different kinds of renewable feedstocks, such as ethanol. In this sense, hydrogen could be treated as biofuel. Three chemical reactions can be used to achieve this purpose: steam reforming (SR), partial oxidation (PDX), and autothermal reforming (ATR). In this study, the catalysts implemented in steam reforming of ethanol were reviewed. A wide variety of elements can be used as catalysts for this reaction, such as base metals (Ni; Cu and Co) or noble metals (Rh, Pt and Ru), usually deposited on a support material that increases surface area and improves catalytic function. The use of Rh, Ni and Pt supported or promoted with CeO2, and/or La2O3 shows excellent performance in ethanol SR catalytic process. The ratio of water to ethanol, reaction temperatures, catalysts loadings, selectivity and activity are also discussed, as they are extremely important for high hydrogen yields.224327332Sao Paulo Research Foundation - FAPESP [2014/14754-0]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Numerical simulation CFD in the quenching process

Orientadores: Rubens Maciel Filho, Andre Luiz Jardini MunhozDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuimicaResumo: Em tratamentos térmicos de têmpera há uma grande dificuldade em entender os diferentes perfis de resfriamento que ocorrem na superfície e no interior dos materiais, e que definem o controle da estrutura formada e das propriedades finais desejadas. A formação de diferentes tipos de estruturas no mesmo material pode ocorrer devido ao resfriamento não uniforme provocado pelas condições fluidodinâmicas do tanque e do fluido refrigerante, os quais determinam as taxas de resfriamento e o valor do coeficiente de transferência de calor. Além disso, há muito pouco na literatura sobre os critérios para a construção de tanques de têmpera. Portanto este trabalho investiga por meio da Fluidodinâmica Computacional (CFD), utilizando o software ANSYS CFX® 11, duas configurações de um sistema de agitação submerso em tanque de têmpera e o impacto das condições fluidodinâmicas e das propriedades físicas do fluido sobre a uniformidade do resfriamento e no coeficiente de transferência de calor na interface do bloco de aço. Como conseqüência as simulações permitem a verificação de alternativas de como o processo pode ser melhorado a partir deste tipo de análise. O processo físico estudado consiste no resfriamento de um bloco de aço nas dimensões 2,3m x 1,2m x 0,86m imerso em tanque com água de dimensões 8,7m x 2,8m x 4,0 m com um sistema de agitação de jato submerso distribuídos em vários bicos reguladores de saída de água. Foram realizadas duas simulações, a primeira envolvendo o sistema de agitação localizado sob o bloco. Na segunda, entretanto, foi acrescentado um sistema de agitação localizada nas laterais do material na tentativa de homogeneizar o fluxo do fluido entorno do bloco, consequentemente sobre a uniformidade do resfriamento. Os resultados deste trabalho indicam que o sistema foi suscetível a variação das propriedades físicas do fluido e do fluxo sobre o material o que levou a grandes variações na curva de resfriamento para o primeiro caso. Contudo, a implementação do sistema lateral de agitação promoveu uma melhora significativa na uniformidade da têmpera, além disso, o modelo foi capaz de predizer as curvas de resfriamento, os coeficientes de transferência de calor na interface do material, e os fluxos do fluido no tanque. A análise discutida fornece informações de como o software pode melhorar o controle do processo de resfriamento por estudos sobre a uniformidade da têmpera, o que pode auxiliar os engenheiros na concepção e desenvolvimento de novos projetos de tanque levando-se em consideração a forma e o tipo do sistema de agitação, bem como a geometria do tanque e do material, e o fluido utilizado no processo. Esta abordagem pode produzir melhorias significativas na qualidade do material enquanto simultaneamente prevê condições para redução de distorções do material durante o tratamento térmico.Abstract: In the quenching heat treatment is a great difficulty to understand the different cooling profiles occurring at the surface and subsurface of the material, that define the structure formed and the final properties desired. The formation of different types of structures in the material can occurs due to uneven cooling caused by fluid dynamic conditions of the tank, which determine the cooling rates and the heat transfer coefficient. Moreover, there is very little literature concerning the criteria for the construction of quenching tanks. Therefore in this work was analyzed by means of Computational Fluid Dynamics (CFD), two configurations of submerged agitation system and the impact of fluid dynamic conditions and the physical properties of the fluid on the cooling uniformity and the heat transfer coefficient at the interface of the steel block. The simulations performed allow the verification of alternatives of how the process can be improved from this type of analysis. The physical process studied consist in the cooling of a steel block with dimensions 2.3m x 1.2m x 0.86m immersed in water tank with dimensions 8.7m x 2.8m x 4.0m with submerged agitation system. There were two simulations, the first involving the agitation system located under the block. In the second, however, was added agitation system located next the sides of the material in an attempt to homogenize the fluid flow around the block, consequently on the uniformity of cooling. The results indicate that the system was susceptible to variations in the fluid properties and fluid flow on the material which led to large variations in the cooling curve for the first case. The implementation of the sideway agitation system led to a significant improvement in uniformity of quenching, in addition, the model was able to predict the cooling curves, the heat transfer coefficient at the interface of the material, and fluid flow in the tank. The analysis provides information about how software can improve the control of the cooling process by studies of quench uniformity, which can help engineers in the design and development of new tank taking into account the type of agitation system, tank geometry and material, and the fluid used in the process. This approach can produce significant improvements in the quality of the material while simultaneously provide conditions to reduce distortions in the material during heat treating.MestradoMestre em Engenharia Químic

Parametric Analysis of Rib Pillar Stability in a Longitudinal Sublevel Open Stoping Operation in an Underground Copper Mine in Southern Africa

The pillar stability factor (PSF) is calculated in three different mining stages for a sublevel open stoping mining project located in northern Botswana. Several three-dimensional finite element models were developed by varying the stope span. Pillar strength was estimated using the Lunder and Pakalnis equation and pillar stress was obtained from the numerical models. As mining progresses, both the first and second mining stages meet the rib pillar stability factor requirement for safe extraction. Geometrical improvements are suggested in the mining layout for the third mining stage to achieve the required PSF, which is based on international practices

Design, fabrication and testing of a catalytic microreactor for hydrogen production from ethanol steam reforming

Orientadores: Rubens Maciel Filho, André Luiz Jardini MunhozTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuímicaResumo: Atualmente, o conceito de sustentabilidade vem ganhando cada vez mais espaço e com ele os desafios de melhorar cada vez mais os processos industriais. Assim, tanto as engenharias quanto as ciências de base têm se dedicado à integração do conhecimento para projetar e implementar soluções inovadoras e ambientalmente equilibradas. Neste contexto, o uso dos microrreatores surge como uma opção atraente e com potencial para atender às diversas e crescentes exigências ambientais e econômicas. Portanto, o principal objetivo desta tese foi projetar fabricar e testar um microrreator catalítico para produção de hidrogênio a partir da reforma a vapor do etanol. Para o cumprimento deste objetivo, quatro etapas principais foram desenvolvidas. A primeira delas foi à 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 com o menor valor no desvio padrão relativo. Na segunda etapa, a tecnologia de manufatura aditiva de sinterização direta em metal a laser (DMLS) foi avaliada para a fabricação dos componentes do microrreator mostrando um grande potencial, principalmente por oferecer condições para produção de superfícies porosas. Apesar disso, as peças assim obtidas apresentaram distorções notáveis devido à alta energia do laser, sendo necessários mais estudos dos parâmetros de fabricação a fim de se obter peças com boa qualidade. Por essa razão e para garantir uma boa integração entre os componentes, a estrutura de compartimento do microrreator e as placas de microcanais foram obtidas por métodos convencionais de usinagem e corrosão química. Na terceira etapa, um método de otimização multicritério foi descrito para se investigar e sugerir uma faixa de parâmetros operacionais do microrreator como temperatura, fração de massa de etanol e fluxo volumétrico de alimentação. Nesta fase, entre os três modelos cinéticos selecionados, apenas um foi considerado o mais confiável para se estender o estudo de otimização e assim sugerir uma faixa de operação do microrreator. Na etapa final, testes experimentais da reação de reforma a vapor do etanol foram conduzidos sob duas diferentes composições de catalisadores, Ni/Al2O3 e Ni/CeO2, com o objetivo de se conhecer as principais reações. Os resultados mostraram que a desidratação e decomposição do etanol foram predominantes em ambos catalisadores, porém foi observada a supressão da desidratação em temperatura de 500 e 600ºC. Entre os catalisadores estudados o Ni/CeO2 foi o mais seletivo e promissor, pois foi capaz não somente de suprimir as reações indesejadas, como a formação de coque, mas por fornecer alta produtividade e rendimento comparado com o Ni/Al2O3. Além disso, ficou demonstrado que o projeto do microrreator proposto foi capaz de produzir hidrogênio com rendimentos significativos, próximo a 100% em altos tempos de residência, sendo, portanto, uma boa opção a ser considerada tanto para aplicações em pequena quanto em grande escalaAbstract: Currently, the concept of sustainability is gaining more prominence and with it the challenges to improve industrial processes. Thus, both engineering as the basic sciences has been devoted to integrate knowledge to design and implement innovative and environmentally balanced solutions. In this context, the use of microreactors emerges as an attractive option and with potential to meet various environmental and economic requirements. Therefore, the objective of this thesis was to design, fabricate and test a catalytic microreactor for hydrogen production from ethanol steam reforming. To achieve this objective, four main steps were developed. Firstly, studies of the fluid dynamic behavior of microreactor were 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. In the second step, the additive manufacturing technology of Direct Metal Laser Sintering (DMLS) was evaluated to fabricate the microreactor components. This technology showed a great potential, especially to provide conditions to produce pieces with porous surfaces. Nevertheless, the pieces obtained by this process showed remarkable distortions due to the high laser energy, necessitating further study about fabrication parameters in order to improve the quality of the parts. For that reason and also to ensure good integration among the components, the housing structure and microchannel plates were obtained by conventional methods of milling cutter and wet chemical etching, respectively. In the third step, a multicriteria optimization method was described to investigate and suggest a range of operating parameters such as temperature, ethanol mass fraction and volumetric flow. Among the three kinetic models selected, only one was considered the most reliable to extend the study of optimization and thus to suggest a range of operation conditions of the microreactor. In the final step, experimental tests of ethanol steam reforming were conducted under two different compositions of catalysts, Ni/Al2O3 and Ni/CeO2, with the aim of knowing the main reactions. The results showed that the ethanol dehydration and decomposition were predominant in both catalysts, but the suppression of the dehydration in the temperatures of 500 to 600°C was observed. Also, among the catalysts studied, the Ni/CeO2 was the most promising not only because it was able to suppress the undesired reactions, but also to provide a high productivity and yield compared to the Ni/Al2O3. Furthermore, it was shown that the design of microreactor was able to produce hydrogen with significant yields, close to 100% at high residence times, and is therefore a good option to be considered in applications ranging from small to large scalesDoutoradoDesenvolvimento de Processos QuímicosDoutor em Engenharia Químic

Caracterisation de la productivite des aquiferes du socle de la region de l’extreme Nord, Cameroun

Dans la zone de socle de la région de l’Extrême Nord du Cameroun, l’exploitation des ressources en eau souterraine permet de faire face au problème de l’alimentation en eau potable des populations rurales. Une meilleure connaissance de ces aquifères est nécessaire pour une bonne productivité. La présente étude a été effectué pour identifier les principaux paramètres hydrauliques essentiels dans la productivité des aquifères de ce socle. Pour ce faire, une compilation de données regroupant les fiches techniques de forage de même que les essais de pompage disponibles dans ce socle a été faite. Ces données concernent les paramètres tels que : le débit de forage (Q), la profondeur totale (Pt) et l’épaisseur d’altérites (EA). Les paramètres hydrauliques notamment la transmissivité (T) et le débit spécifique (Qs) ont été déterminés à partir de l’interprétation des essais de pompage issus des données des fiches. La transmissivité a été calculée par la méthode de Cooper Jacob avec les données de rabattement des ouvrages disponibles après l’arrêt du pompage lors de la remontée. Une analyse statistique de ces paramètres physiques et hydrauliques déterminés a été réalisée. Il ressort que les débits des forages oscillent entre 0,04 m³/h et 4 m³/h avec une moyenne de 1,66 m3/h. Les classes de débits très faible et faible représentent 74,57% des débits de forage de cette zone. Les forages productifs ont une profondeur totale comprise entre 30 et 75 m avec une épaisseur d’altérites qui varie entre 1m et 14 m. Les formations granitiques et métamorphiques semblent être productives, avec 47,46% des débits se trouvant dans la classe des débits faible à moyenne (Q e” 1m³/h). Les valeurs de transmissivité fluctuent entre 3x10-7 m²/s et 7,80x10-4 m²/s avec une moyenne de 5,03x10-5 m²/s. Elle illustre que les aquifères de socle de la région de l’Extrême Nord ont une faible fonction conductrice.Mots Clés: Productivité, aquifères, zone de socle, Extrême Nord, CamerounEnglish AbstractIn the socle zone of the extreme North region of Cameroon, the exploitation of groundwater resources makes it possible to cope with the problem of the supply of drinking water to rural populations. A better knowledge of these aquifers is necessary for good productivity. The present study was carried out to identify the main hydraulic parameters essential in the productivity of the aquifers of this socle zone. To do this, a compilation of data gathering the drilling data sheets as well as the pumping tests available in this socle was made. These data relate to parameters such as: flow of drilling (Q), total depth (Pt) and thickness of alterites (EA). The hydraulic parameters in particular the transmissivity (T) and specific flow rate (Qs) were determined from the interpretation of the pumping tests from the data the data sheets.The transmissivity was calculated by the Cooper Jacob method with the rabattement data of the works available after the stop of pumping at the time of the ride up. A statistical analysis of these parameters of given drillings and hydraulics was carried out. Borehole flow rates range from 0.04 m³ /h to 4 m³ / h with an average of 1.66 m3 / h. The very weak and weak flow classes account for 74.57% of the flow of drilling in this zone. The productive boreholes have a total depth of between 30 and 75 m with a thickness of alterites which varies between 1 m and 14 m. The granitic and metamorphic formations appear to be productive, with 47.46% of the flows in the low to medium flows class (Q e”1 m³ / h).Transmissivity values fluctuate between 3x10-7 m² / s and 7.80x10-4 m² / s with an average of 5.03x10-5 m² / s. It illustrates that the basement aquifers of the extreme North region have a weak conductive function.Keywords: Productivity, aquiferes, socle zone, Extreme North, Cameroo

Synthesis of carbon nanostructures by chemical vapour deposition over Ni-Al co-oxides using plastic solid waste as precursor

Europe contributed with 18.5% of the almost 3!50 Mton of plastics produced worldwide in 2017. Polypropylene (PP) and light and heavy density polyethylene (LOPE and HOPE, respectively) represents near 49.1% of the plastics produced in Europe. Packaging is the main application of these plastics, so typically they have one-single use. In 2014, 25.8 Mton of post-consumer plastic solid wastes (PSWs) ended up in the official waste streams (54.0% of the demanded quantity), 69.2% being recovered through recycling (7.7 Mton) and enen~y recovery processes (10.2 Mton), the remaining 30.8% sent to landfill [1]. Concerns about usage and disposal are diverse and include accumulation of PSWs in landfills and in natural habitats, physic;al problems for wildlife resulting from ingestion or entanglement in plastic and the leaching of chemicals from plastic products [2]. The incineration of PSWs contributes to pollution due to harmful and tC»xic emissions and both incineration and mechanical recycling are costly and may or may not be economically viable in different situations [3]. More attractive strategies are the production of carbon nanomate!rials using PSWs as carbon precursors [4]. In this work, Ni-AI eo-oxide nanoparticles were synthesiz,ed by eo-precipitation and employed as catalysts in the chemical vapour deposition of CNTs when using LOPE as carbon precursor and as model compound of plastic solid waste. Fig. 1 shows the scanning electron micrographs of the carbon nanostructures prepared at 1000 °C during 1 h in a tubular furnace under 10 NmL·min·1 nitrogen flow. As can be observed, CNTs and carbon nanospheres were produced.This work is a result of Project "PLASTIC_TO_FUEL&IMATs - Upcycling Waste Plastics into Fuel and Carbon Nanomaterials", with the reference POCI-01-0145-FEDER-031439, through the Competitiveness and Internationalization Operational Program. supported by the European Regional Development Fund (ERDF); the Associate Laboratory LSRE-LCM- UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC); and CIMO UID/AGR/00690/2019 through FEDER under Program PT2020.info:eu-repo/semantics/publishedVersio

Life cycle environmental impacts of vineyard in the south Portugal

Agricultural activities have multiple negative impacts on the environment. In the wine sector, several studies have used the life cycle approach to identify and measure these environmental impacts. The main aim of this study was to determine the environmental impact of two vineyards located in southern Portugal, considering 1 kg of grape yield, using the life cycle assessment (LCA) methodology (ISO 14040). The system boundary studied was “from cradle to gate” including grape production and harvesting. The methodology included the use of GaBi software for the assessment of different impact categories (CML 2001 Methods), including the global warming potential (GWP), acidification potential (AP), eutrophication potential (EP) and abiotic depletion potential (AD). The results show that the contribution in the AP and EP categories were associated with the use of agricultural machinery, while the AD was mostly due to external inputs, namely the production of pesticides. On the other hand, the GWP category, received a very equitable contribution among all production processes. This study allowed for the identification of which production processes may contribute the most to the different environmental impacts, thus prompting the identification of improvement opportunities for more sustainable production in the vineyards stages of the wine production.This study received funding from COMPETE 2020 - Programa Operacional Competitividade e Internacionalização (POCI-0145-FEDER-023360), Wine WATERFootprint project. The authors would also like to thank the Foundation for Science and Technology (FCT, Portugal) and FEDER under the PT2020 Program for the financial support to CIMO UID/AGR/00690/2019. Our thanks must also go to the farmers, companies and specialists in the wine sector for their kind collaboration in this study, through the provision of relevant data and information.info:eu-repo/semantics/publishedVersio

Synthesis of lanthanide compounds with iminic ligands and its application at the polymerization of methyl methacrylate

Orientadores: Ulf Friedrich Schuchardt, Wanda de OliveiraDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuimicaResumo: Estudou-se a síntese do complexo de samário (III) com 2 ligantes 2-(2,6- diisopropilfenil)aminopent-2-en-4-(2,6-diisopropilfenil)imina [(2,6DIPPh)2nacnac]. A síntese do complexo foi conduzida em atmosfera inerte e THF como solvente através da adição de 2 equivalentes do ligante ionizado sobre o brometo de samário e subseqüente adição de 2 equivalentes de butil-lítio. O complexo foi caracterizado por ressonância magnética nuclear de H e C, espectroscopia na região do visível e espectroscopia de emissão atômica com plasma indutivamente acoplada, para determinar a quantidade de Sm e Li presentes no complexo e argentometria para determinação do Br. A atividade catalítica do complexo foi testada na polimerização do metacrilato de metila. Os testes catalíticos foram conduzidos em atmosfera inerte utilizando tolueno como solvente e variando condições reacionais como tempo, temperatura e razão catalisador/monômero. Observou-se que a ordem de adição dos reagentes durante a síntese do complexo é um fator decisivo para a atividade do catalisador e que as melhores condições de polimerização ocorreram à 0 °C, com uma razão monômero/catalisador de 90 durante 30 minutos de reação, gerando 90 % de rendimento em polímeros. Os produtos obtidos foram caracterizados por cromatografia de permeação em gel, análise termogravimétrica, espectroscopia na região do infravermelho, ressonância magnética nuclear de H e C e calorimetria diferencial de varredura. Os polímeros apresentaram massa molar (Mw) da ordem de 25 000 g mol com um baixa polidispersão (1,30), sendo pred) eominantemente isotático (55 %) e uma temperatura de transição vítrea (Tg) em torno de 60°C.Abstract: The synthesis of the samarium complex with 2 ligands 2-(2,6- diisopropylphenil)aminopent-2-en-4(2,6-diisopropylphenil)imine [(2,6DIPPh)2nacnac] was studied. The synthesis was carried out under inert atmosphere, by the addition of 2 equivalents of the ionized ligand under the samarium bromide and then were added 2 equivalents of butil-lithium. The complex was characterized by nuclear magnetic resonance of H and C, visible spectroscopy, atomic emission spectroscopy with induced coupled plasma to determine the amount of Sm, Li present in the complex and Br was determinatéd by argentometry. The catalytic activity of the complex was studied through the polymerization of methyl methacrylaté. The catalytic tests were carried out under inert atmosphere using toluene as solvent and changing reaction conditions such as monomer : catalyst molar ratio, temperature and time dependence. It was observed that the order of addition is a important factor to determine the catalyst activity and that the best conditions to the polymerization reaction are monomer/catalyst molar ratio: 90, 30 minutes of reaction at 0 °C, giving polymers with 90 % of yield. The polymers were characterized by H and C nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, thermogravimetric analysis and differential scanning calorimetry (DSC). The polymers showed molar masses (MW) around 25 Kg mol with low polydispersivity (1.30), 55% isotactic with glass transition temperature around 60°C.MestradoQuimica InorganicaMestre em Químic

Aspects of the distribution of agricultural activity: An analysis for Brazilian microregions from 1991 to 2018

O objetivo deste trabalho é identificar, para o caso do Brasil, as mudanças nos padrões de localização e distribuição da atividade econômica agrícola entre os anos de 1991 e 2018. Utilizando-se de dados de emprego agrícola extraídos da Relação Anual de Informações Sociais (RAIS) e do Valor da Produção Agrícola extraídos do banco de dados da PAM (Produção Agrícola Municipal), foi elaborada uma Análise Exploratória dos Dados Espaciais (AEDE), apresentando a distribuição espacial por quintis, o I de Moran Global, e a análise do I de Moran Local (Análise LISA, ou análise de agrupamentos) para o Quociente Locacional (QL) do emprego agrícola e o Valor da Produção Agrícola (VPA) em 1991, 2000, 2010 e 2018. Os resultados indicam um deslocamento e uma expansão do QL do Emprego Agrícola e do Valor da Produção Agrícola no território brasileiro ao longo do tempo: a localização passa de áreas agrícolas tradicionais como São Paulo e os estados da Região Sul para áreas caracterizadas como “Novas Fronteiras Agrícolas”. Além disso, os resultados são semelhantes tanto para o Quociente Locacional do emprego agrícola e do Valor da Produção Agrícola. Este trabalho contribui para o preenchimento de uma lacuna nos estudos da geografia do desenvolvimento econômico sobre a evolução espacial do setor agrícola no Brasil nas últimas décadas.The objective of this work is to identify, in the case of Brazil, the changes in the patterns of location and distribution of agricultural economic activity between 1991 and 2018. Using agricultural employment data extracted from the Annual Report of Social Information (RAIS) and the Value of Agricultural Production extracted from the PAM (Municipal Agricultural Production) database, an Exploratory Analysis of Spatial Data (AEDE) was prepared, presenting the spatial distribution by quintiles, the Moran´s Global I, and the analysis of Moran's Local I (LISA Analysis, or cluster analysis) for the Location Quotient (QL) of agricultural employment and the Value of Agricultural Production (VPA) in 1991, 2000, 2010 and 2018. The results indicate a shift and an expansion of the Agricultural Employment´s QL and the Value of Agricultural Production in the Brazilian territory over time: their location move from traditionally agricultural areas such as São Paulo and the states of the South Region to areas characterized as “New Agricultural Frontiers”. Furthermore, the results are similar for both the Agricultural Employment´s Location Quotient and the Value of Agricultural Production. This work contributes to filling a gap in studies of the geography of economic development on the spatial evolution of the agricultural sector in Brazil in recent decades.Não recebi financiament