Zeolite membranes are considered to be a promising alternative to polymeric membranes and they have the potential to separate gases under harsh conditions. Silicalite-1 membranes in particular are easy to prepare and suitable for several industrial applications. In this research project, silicalite-1/ceramic composite membranes were prepared using the pore plugging hydrothermal synthesis method and supports with zirconium oxide and/or titanium oxide as active layers. The effect of the support’s pore size on the morphology and permeation performance of the prepared membranes was investigated using five supports with different active layer pore sizes in the range of 0.14 – 1.4 m. The prepared membranes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), electron diffraction spectrometer (EDS), single gas and binary gas mixtures permeation tests. The results confirmed the presence of a typical silicalite-1 zeolite structure with a high internal crystalline order grown inside the pores of the active layer of the supports, with a dense film covering most of the supports active layers. Silicalite-1 crystals in the prepared membranes were preferably oriented with either a- or b-axes perpendicular to the support surface. Single gas permeation results illustrated that the observed permeances were not directly related to the kinetic diameter of permeants. Instead, the transport of the studied gases through the prepared membranes occurred by adsorption followed by surface diffusion mechanism. Binary gas tests performed with CO2 and N2 mixtures showed that the prepared membranes were selective and very permeable with CO2/N2 permselectivities up to 30 and a CO2 permeances in the order of 10-6 mol m-2 Pa-1 s-1. A model was developed, based on Maxwell−Stefan equations and Extended Langmuir adsorption isotherm, to describe the transport of binary CO2 and N2 mixtures through the prepared silicalite-1 membranes. The model results showed that the exchange diffusivities (D12 and D21) were less dependent on the feed pressure and feed composition compared to the permeances and the permselectivities. Hence, they are more appropriate to characterize the intrinsic transport properties of the prepared silicalite-1 membranes.

Orientador: Matthieu Tubino / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-21T17:49:21Z (GMT). No. of bitstreams: 1 Mattos_RodrigoAlvesde_D.pdf: 2518556 bytes, checksum: a8c7635c9785df284e4cea0c8053443c (MD5) Previous issue date: 2012 / Resumo: O presente trabalho foi realizado usando biodieseis preparados a partir de óleos de soja, canola, milho, girassol e, também, de gordura suína, através de reações transesterificação. Para todos esses biodieseis foram determinados o ponto de entupimento a frio, o ponto de fulgor e o perfil cromatográfico. Estes biodieseis foram misturados com diesel de petróleo para se produzir misturas contendo 5% do biocombustível (B5), 10% (B10) e 20% (B20), e os ensaios citados foram realizados nestas amostras. Visando a diminuição do ponto de entupimento a frio, alguns aditivos naturais foram testados e se mostraram eficientes. Por exemplo, o limoneno reduziu o ponto de entupimento do biodiesel de óleo soja em mais de 7°C. No biodiesel de gordura suína a redução foi de 10°C, o que significa o ponto de entupimento a frio em temperatura inferior a 13°C. Os aditivos utilizados são solúveis nos biodieseis estudados e, também, nas misturas diesel-biodiesel, pelo menos nas concentrações testadas. Como importante exemplo de abaixamento do ponto de entupimento a frio das misturas diesel-biodiesel de gordura suína com 10% de biodiesel (B10), podese citar o caso da terebentina que provocou uma redução de aproximadamente 8°C (de 12,7ºC para 5,0°C). Este mesmo aditivo caus ou uma redução de 13,6 ºC (de 20,3ºC para 6,7ºC), na mistura diesel-biodiesel de gordura suína com 20% de biodiesel (B20). Este resultado é muito significativo por implicar na possibilidade de usar este tipo de combustível mesmo em regiões mais ao sul do país durante o inverno / Abstract: The present studies were performed preparing biodiesel from soya, canola, corn, sunflower oils and the fat swine, through transesterification reaction. The biodiesel produced from these oils were studied for: cold filter plugging point, flash point and for chromatographic analysis. The biodiesels were mixed with diesel to produce blends containing 5% of the biofuel (B5), 10% (B10) and 20% (B20), and these samples were also analyzed by the same techniques as discussed earlier. In order to decrease the cold filter plugging point, some natural additives have been tested and were proved effectively. For example, limonene caused more than 7°C reduction in the cold filter plugging point of soybean biodiesel. In the biodiesel obtained from the swine fats, the reduction was found around 10°C and less than 13°C for the cold filter plugging point. The additives are soluble in studied biodiesels and also in the dieselbiodiesel blends, at least, in the concentrations tested. One of the important example of the reduction in the cold filter plugging point of diesel-biodiesel blends of swine fats with 10% biodiesel (B10), using turpentine as additive which caused reduction of approximately 8°C (from 12,7ºC up to 5,0°C). The same additive caused a reduction of 13,6 ºC (from 20.3 ºC up to 6.7 °C) in the cold filter plugging point of diesel -biodiesel blends of swine fats with 20% biodiesel (B20). This result is very significant because it is possible to use this type of fuel in south regions of the country during the winter / Doutorado / Quimica Analitica / Doutor em Ciências

Zeolite membranes are considered to be a promising alternative to polymeric membranes and they have the potential to separate gases under harsh conditions. Silicalite-1 membranes in particular are easy to prepare and suitable for several industrial applications. In this research project, silicalite-1/ceramic composite membranes were prepared using the pore plugging hydrothermal synthesis method and supports with zirconium oxide and/or titanium oxide as active layers. The effect of the support’s pore size on the morphology and permeation performance of the prepared membranes was investigated using five supports with different active layer pore sizes in the range of 0.14 – 1.4 m. The prepared membranes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), electron diffraction spectrometer (EDS), single gas and binary gas mixtures permeation tests. The results confirmed the presence of a typical silicalite-1 zeolite structure with a high internal crystalline order grown inside the pores of the active layer of the supports, with a dense film covering most of the supports active layers. Silicalite-1 crystals in the prepared membranes were preferably oriented with either a- or b-axes perpendicular to the support surface. Single gas permeation results illustrated that the observed permeances were not directly related to the kinetic diameter of permeants. Instead, the transport of the studied gases through the prepared membranes occurred by adsorption followed by surface diffusion mechanism. Binary gas tests performed with CO2 and N2 mixtures showed that the prepared membranes were selective and very permeable with CO2/N2 permselectivities up to 30 and a CO2 permeances in the order of 10-6 mol m-2 Pa-1 s-1. A model was developed, based on Maxwell−Stefan equations and Extended Langmuir adsorption isotherm, to describe the transport of binary CO2 and N2 mixtures through the prepared silicalite-1 membranes. The model results showed that the exchange diffusivities (D12 and D21) were less dependent on the feed pressure and feed composition compared to the permeances and the permselectivities. Hence, they are more appropriate to characterize the intrinsic transport properties of the prepared silicalite-1 membranes.

During impact driving of open-ended piles through cohesion-less soil the internal soil column may mobilize enough internal shaft resistance to prevent new soil from entering the pile. This phenomena, referred to as soil plugging, changes the driving characteristics of the open-ended pile to that of a closed-ended, full displacement pile. If the plugging behavior is not correctly understood, the result is often that unnecessarily powerful and costly hammers are used because of high predicted driving resistance or that the pile plugs unexpectedly such that the hammer cannot achieve further penetration. Today the user is generally required to model the pile response on the basis of a plugged or unplugged pile, indicating a need to be able to evaluate soil plugging prior to performing the drivability analysis and before using the results as basis for decision. This MSc. thesis focuses on soil plugging during impact driving of open-ended piles in cohesion-less soil and aims to contribute to the understanding of this area by evaluating models for predicting soil plugging and driving resistance of open-ended piles. Evaluation was done on the basis of known soil plugging mechanisms and practical aspects of pile driving. Two recently published models, one for predicting the likelihood of plugging and the other for predicting the driving resistance of open-ended piles, were compared to existing models. The main outcomes from the model evaluations are: • Internal shaft resistance, pile diameter and pile velocity/acceleration were found to be the primary input parameters affecting the result in the models used to predict if soil plugging is likely to occur. • The pile diameter was shown to have less influence on the calculated driving resistance in the recently published model, derived from measurements of plug length ratios, compared to in the existing model. This thesis also includes a full-scale field study conducted during the initial piling operations for the construction of the new Värtahamnen seaport in Stockholm (Sweden). The soil conditions cause the piles to be driven through very dense post glacial moraine, in which little is known about soil plugging. The drivability performance of 146 open-ended and closed-ended steel pipe piles with diameters ranging from 914-1168 mm was compared through analysis of driving records. The aim was to evaluate if open-ended piles resulted in a drivability related gain and if so during which part of the installation process. The driving records were used to quantify the performance in terms of driving time and energy required to drive the piles. The main conclusions from the field study are: • Significant time savings were achieved by using open-ended piles instead of closedended piles. The time advantage was bigger during impact driving, compared to vibratory driving, and on average the impact driving of open-ended piles took 9 minutes versus 26 minutes for closed-ended piles. • Contrary to what was expected, namely that the open-ended piles would result in lower driving resistance, the results indicate that the majority of the time savings came from open-ended piles being more stable during driving and thereby requiring fewer adjustments. / Under slagdrivning av öppna pålar i friktionsjord förekommer det att den interna jordpelaren mobiliserar tillräckligt mycket internt mantelmotstånd för att förhindra inträngning av ny jord. Detta fenomen, på svenska vanligen kallat jordpluggning, medför att drivbeteendet för pålen övergår till att likna det hos en sluten och massundanträngande påle. Oförmåga att på ett korrekt sätt beakta jordpluggning medför ofta att drivmotståndet för öppna pålar antingen överskattas, vilket medför att onödigt kraftfull och kostsam utrustning används, eller underskattas vilket kan medföra att pålen pluggar och inte kan drivas till avsett djup. I dagsläget kräver drivbarhetsanalyser generellt sett att användaren måste modellera pålen som en pluggad eller opluggad påle. Detta medför att det finns ett behov att kunna utvärderajordpluggning innan drivbarhetsanalysen genomförs, samt även vid utvärdering av resultaten från drivbarhetsanalysen. Detta examensarbete fokuserar på jordpluggning vid slagdrivning av öppna pålar i friktionsjord och syftar till att öka kunskapen inom området genom att utvärdera modeller som kan användas för att uppskatta huruvida jordpluggning är sannolikt, samt modeller för att uppskatta drivmotståndet för öppna pålar. Utvärderingen av nämnda modeller skedde med utgångspunkt i kända mekanismer som förknippas med jordpluggning, samt i praktiska aspekter av påldrivning. Två nyligen publicerade modeller, en avsedd att utvärdera huruvida pluggning är sannolikt och den andra för att uppskatta det förväntade drivmotståndet, jämfördes med befintliga modeller för samma ändamål. De huvudsakliga slutsatserna av modellutvärderingen är: • Internt mantelmotstånd, pålens diameter samt pålens hastighet/acceleration var de faktorer som hade störst inverkan på resultatet hos de modeller som avser utvärdera huruvida jordpluggning är att förvänta. • Pålens diameter visade sig få mindre inverkan på beräknat drivmotstånd i den nyligen publicerade modellen, baserad på mätningar av plugglängd relativt penetrationsdjup, jämfört med i den befintliga modellen. Examensarbetet innefattar även en fältstudie genomförd under inledningen av pålningsarbetet vid uppförandet av nya Värtahamnen i Stockholm. Markförhållandena på platsen medför att pålarna drivs genom bottenmorän, ett jordförhållande där det i stor utsträckning saknas erfarenheter relaterade till jordpluggning. Med hjälp av pålprotokoll jämfördes drivbarheten hos 146 öppna och slutna pålar med diametrar 914-1168 mm. Målet var att fastställa huruvida öppna pålar medförde ökad drivbarhet och i så fall under vilket skede av drivprocessen. Pålprotokollen användes för att kvantifiera vinsten i form av drivtid samt erforderlig drivenergi. De huvudsakliga slutsatserna från fältstudien är: • Betydande tidsvinst kunde påvisas för öppna pålar, jämfört med stängda pålar. Tidsvinsten var större under slagdrivning än under vibrationsdrivning och i snitt 9 minuter jämfört med 26 minuter för stängda pålar. • I motsats till det förväntade utfallet, nämligen att de öppna pålarna inte skulle plugga, antyder resultaten att majoriteten av tidsvinsten kan kopplas till att de öppna pålarna var mer stabila under drivning vilket resulterade i färre korrigeringar

Membrane processes have received growing attention due to their low energy consumption and ease of operation. Thin-film composite reverse osmosis membranes based on polyamides are the most widely applied commercial membranes, because of their high flux and selectivity. However, their application for gas separation processes is still limited. This is the due to the presence of defects in the membrane when in the dry state. Traditionally, thin-film composite membranes are made by interfacial polymerization between a polar (aqueous) phase and a non-polar (organic) phase. The most commonly applied thin-film composite membranes are made by dissolving m-phenylene diamine in the aqueous phase and trimesoyl chloride in the organic phase. This work investigated the possibility of fabricating thin-film composite membranes when an aliphatic alcohol (methanol, ethanol or isopropanol) is used as the polar phase. This is further extended to examining the ability of a PDMS coating to plug the defects in such layers. The effects of temperature and support type on the membrane performance were also studied. Solubility tests were conducted to determine the solubility limit of commercial and in-house fabricated amine monomers in water, methanol, ethanol and isopropanol. Water-insoluble monomers were found to be soluble in ethanol and methanol. Gas permeation tests were conducted on membranes made using water, methanol, ethanol and isopropanol as the polar phase. The results showed that the membranes produced by aliphatic alcohols had higher selectivities. The highest H2/CO2 selectivity of ~ 26 was observed in the ethanol-based membranes when they were coated with PDMS and tested at 80 C. It was confirmed that PDMS is able to plug the defects in the membrane. Membranes made on the polysulfone support were found to have higher permeance and comparable selectivity relative to the membranes made on the polyacrylonitrile supports. It was also found that a change in the polar phase solvent is able to alter the morphology of the membranes. SEM micrographs showed clear differences in the surface structure of each membrane. The average thickness values obtained from ellipsometry measurements showed a correlation with the interface miscibility. The thickest membrane corresponded to the most miscible interface (IPA/Isopar).

In petroleum production systems, hydrate morphology is observed to be influenced by the crude oil composition. This work is aimed at identifying which crude oil compositional parameters that need to be determined in order to evaluate natural anti-agglomerating properties of crude oils, i.e. the critical compositional descriptors. The compositional features of 22 crude oils have been studied, and multivariate data analysis has been used to investigate the possibility for correlations between several crude oil properties. The results show that biodegradation together with a relatively large amount of acids are characteristic for non-plugging crude oils, while excess of basic compounds is characteristic for plugging crude oils. The multivariate data analysis shows a division of the nonbiodegraded oils, which are all plugging, and the biodegraded oils. In addition, the biodegraded oils seem to be divided into two groups, one with plugging oils and one with mostly non-plugging oils. The results show that the wettability can be predicted from the variables biodegradation level, density, asphaltene content and TAN.

[pt] Operações de posicionamento de tampão de cimento na indústria do petróleo representam um exemplo de escoamento dominado por efeitos gravitacionais. Essa situação é altamente instável visto que o cimento geralmente é mais denso que o fluido do poço e, como consequência, suas posições tendem a se inverterem. O presente estudo objetiva aprimorar a percepção dos mecanismos físicos associados às operações de tamponamento através da análise de escoamentos de inversão por gravidade. Com esta finalidade, executam-se experimentos de visualização com líquido mais denso posicionado sobre outro de menor densidade em tubo vertical. Ademais determina-se a velocidade da interface através do processamento e análise de imagens. A influência dos parâmetros governantes é averiguada sobre a velocidade de inversão e o regime de escoamento. A importância relativa entre as forças gravitacionais, viscosa, inercial e interfacial são avaliadas. A primeira etapa do estudo consiste na realização de experimentos com pares de fluidos newtonianos e imiscíveis com pequena diferença de densidade. Examinam-se dois regimes de escoamento, a saber gotas e slugs em queda. Os resultados experimentais demonstram que a velocidade terminal pode ser estimada por correlações empíricas de esferas rígidas em queda dentro de um tubo. A segunda etapa da pesquisa consiste na análise de escoamento de inversão por gravidade com fluido elasto viscoplástico tixotrópico sobre óleo newtoniano menos denso. Constatam-se três diferentes regimes de escoamento, denominados instável, quase-estável e estável (sem escoamento). O regime instável apresenta escoamento wavy core annular com o líquido mais denso no centro. No regime quase-estável há formação de plug flow após um tempo de retardo, que é função dos efeitos tixotrópicos e elásticos do material. Através da análise dos resultados experimentais é possível identificar, para um dado par de fluidos, a janela de operações no espaço de parâmetros governantes dentro da qual a velocidade de inversão é suficientemente baixa (ou nula) para assegurar o sucesso da operação de tamponamento. / [en] Cement plug placement in oil industry operations represents an example of buoyancy-driven exchange flows. This situation is highly unstable since cement is usually denser than well fluid and, as a consequence, their positions tend to invert. The present study aims to improve the perception of the physical mechanisms associated to cement plug operations through the analysis of exchange flows. To this end, visualization experiments are performed with denser liquid positioned above a lower-density liquid in a vertical tube. In addition, the interface front speed is determined through image processing and analysis. The influence of the governing parameters is investigated on the speed of inversion and flow regime. The first stage of the study consists of conducting experiments with pairs of immiscible Newtonian liquids with small density difference. Two different flow regimes were examined, namely, falling drops and falling slugs. Experimental results demonstrate that the terminal velocity can be estimated by empirical correlations for falling rigid spheres within a tube. The second stage of the research consists of an exchange flow analysis considering an elastoviscoplastic thixotropic fluid above a less dense Newtonian oil. Three different flow regimes were observed, namely unstable, quasi-stable, and stable (no flow). The unstable regime is a wavy core-annular flow with the denser liquid in the core. In the quasi-stable regime a slow plug flow starts after a time delay, which is a function of material thixotropic and elastic effects. Through analysis of the experimental results it is possible to identify, for a given pair of fluids, the operational window in the governing parameter space within which the speed of inversion is sufficiently low (or zero) to ensure the cement plug operation success.

Zeolite membranes have great potential in gas separation applications because of their unique selective properties. The main challenge is in synthesizing defect-free zeolite membranes. In this study, we synthesized silicalite-1 zeolite membranes on ceramic supports composed of Al2O3 and TiO2 using the pore-plugging method. We investigated the effect of the fill-level in the autoclave during the synthesis on the membrane performance. In particular, we were interested in determining the conditions at which the defects' contribution to the total transport is minimized. We adopted and further developed the approach proposed by Carter (2019) to quantify the permeance contribution through defects. Comparing the membrane performance before and after calcination, we proposed several modifications to the original analysis of Carter (2019). Knowing the defect transport contribution, we determined the corrected diffusivity, an intrinsic property of zeolite crystals at a given temperature, of several adsorbed gases on silicalite-1 crystals. The defect's contribution decreased as the autoclave fill-level increased from 94 to 98%. A further increase in the autoclave fill-level introduced more defects and caused the autoclave lid to rupture. Despite the differences in the membranes' performance arising from the autoclave fill-level, the corrected diffusivities of CO2, CH4, and N2 in silicalite-1 showed minimal variation from membrane to membrane. This proves the validity of the proposed characterization method. Moreover, the reported corrected diffusivities are comparable to the literature's values, found using other characterization methods. However, none of the previously used methods is as simple and straightforward as the one we further developed in this study.

[pt] O tamponamento de poços de petróleo é analisado numericamente. Neste processo, um fluido mais denso (pasta de cimento) é colocado sobre outro menos denso (fluido de perfuração) em um poço vertical, resultando em uma situação de instabilidade. O escoamento resultante foi estudado de forma a avaliar se o isolamento do poço ocorreria até o momento da cura do cimento (entre 4 e 5 horas). O cimento foi modelado como fluido não-newtoniano e o fluido de perfuração foi considerado newtoniano em alguns casos e não-newtoniano nos demais casos. A solução do escoamento foi obtida numericamente, usando-se o programa ANSYS Fluent. As equações de conservação são resolvidas empregando-se o Método dos Volumes Finitos e o escoamento multifásico foi modelado utilizando-se o método Volume de Fluido. O comportamento viscoplástico não-newtoniano foi modelado empregando a equação constitutiva do fluido newtoniano generalizado, com a função de viscosidade Herschel-Bulkley. O sucesso da operação foi determinado pela combinação dos parâmetros reológicos e geométricos. O efeito dos parâmetros como a razão entre densidades e viscosidades foi investigado para uma geometria fixa (razão fixa entre o comprimento do tampão e o seu diâmetro). Além disso, a influência dessa mesma razão no processo também foi analisada enquanto outros parâmetros foram mantidos fixos. Foi demonstrado que o escoamento é muito instável e que os parâmetros estudados afetam consideravelmente a operação. / [en] The plugging process of an oil well was analyzed numerically. In this process, the denser fluid is the cement plug, which was placed above the drilling fluid in a vertical well, resulting in an unstable situation. The cement plug was modeled as non-Newtonian and the drilling fluid was considered Newtonian in some cases and non-Newtonian in other cases. The flow solution is studied using the ANSYS Fluent program. The conservation equations were solved using the Finite Volume Method, and the multiphase flow was modeled with the Volume of Fluid method. The non-Newtonian viscoplastic behavior of the cement plug was modeled with the Generalized Newtonian Fluid constitutive equation, with the Herschel-Bulkley viscosity function. The success of the operation was determined by the combination of the governing rheological and geometric parameters. The effect of the governing parameters, such as the density ratio and the viscosity ratio, were investigated for a fixed geometry and a fixed ratio between the cement plug length and diameter. Furthermore, the influence of this ratio in the process was also analyzed while others governing parameters were fixed. It was shown that the flow is highly unstable, and that the governing parameters considerably affect the operation.

Dans les médias d’information, il est de plus en plus régulièrement question, recherches scientifiques à l’appui, du danger que poserait la connexion pour tous ceux et celles qui passent trop de temps branché.e.s à des appareils numériques. Une charge normative est ainsi apposée sur la connexion et le temps. Ce mémoire explore la conception de la connexion par les personnes qui la vivent et l’interrogent au quotidien. L’objectif est aussi de comprendre comment celle-ci pourrait orienter leurs expériences du temps ou comment elle pourrait être tributaire des temporalités induites par la société. La méthodologie de cette recherche exploratoire a pris la forme d’entrevues semi-dirigées menées à Montréal auprès de quatre personnes « connectées » et réfléchissant la connexion au quotidien. Nous nous rencontrions une fois par semaine pendant un mois et les participant.e.s remplissaient régulièrement un journal de bord qu’iels me présentaient ensuite, pour amorcer nos rendez-vous. À la lumière de l’analyse des transcriptions d’entrevues, je suggère que les participant.e.s ont en commun différentes approches de la dé-connexion. Cette dernière peut se conceptualiser en termes d’infrastructures, d’artefacts et de symboles. Aussi, différentes temporalités parcourent, modulent et son modulées par la dé-connexion vécue comme un moyen de s’intégrer socialement et de viser un idéal de connexion (temporellement) équilibré. / Based on various scientific studies, news media discourse address more and more regularly the danger posed by connection to all of those who spend too much time using digital devices. A normative load is therefore placed on connection and time. This research project aims to: a) explore what connection means to people whose daily lives involve being connected and questioning their connection; and b) to understand how their approach to connection may orient their experiences of time while at the same time being affected by the temporalities around which today’s societies are organized. The methodological approach that guides this exploratory research features semi-structured interviews conducted in Montreal with four “connected” people who questioned the place of connection in their daily lives. We met once a week for a month and the participants regularly filled out a logbook which they then presented to me at the beginning of each of our conversations. Based on the analysis of interview transcripts, I suggest that the participants share different approaches to dis-connection. The latter can be conceptualized in terms of infrastructure, artifacts and symbols. Also different temporalities modulate and are modulated by this dis-connection as people experience it as a means to fit in, and to aim for an ideal (time) balanced practice.