Os grandes campos de petróleo offshore recentemente descobertos na camada pré-sal, localizada no sudeste do Brasil, representam um avanço significativo da participação brasileira nas reservas mundiais de hidrocarbonetos, que ainda são a principal matriz energética mundial. Nesse cenário, torna-se importante o desenvolvimento da produção desses campos. Um dos principais desafios tecnológicos da exploração desses campos é o processamento do gás natural associado, que possui altos teores de dióxido de carbono CO2. Esse contaminante deve ser separado para possibilitar a injeção no reservatório e/ou o escoamento desse gás através de dutos submarinos, dadas as restrições na legislação ambiental. Nas plantas de processamento instaladas no convés de grandes embarcações, são previstas instalações para a separação do CO2 e a remoção de umidade do gás a fim de evitar a formação de hidratos e a corrosão acentuada das linhas de escoamento, pois tanto a injeção quanto a exportação do gás são realizadas em condições de pressão e temperaturas extremas. Nesse contexto, o conhecimento acurado das condições em que se forma uma fase aquosa líquida é importante para garantir a viabilidade técnica e de segurança dessas operações. Considerando a relevância do assunto e as limitações da literatura para os cenários enfrentados no pré-sal brasileiro, esse trabalho tem o objetivo de fazer um estudo abrangente do equilíbrio de fases em sistemas contendo hidrocarbonetos em fase gasosa com altos teores de CO2 e traços de água, visando à obtenção de modelo para cálculo do ponto de orvalho da água. O uso de modelos rigorosos baseado na teoria dos fluidos associativos (PC-SAFT) mostrou-se adequado para o cálculo das condições de saturação em amplas faixas de pressão e temperatura. Com base em dados experimentais publicados foi possível fazer um ajuste preciso dos parâmetros de interação binária da equação de estado PC-SAFT. Como resultado, obteve-se um modelo capaz de descrever o comportamento de fases em misturas de hidrocarbonetos com composição próxima das encontradas no pré-sal brasileiro. / The giant offshore petroleum fields recently discovered in the pre-salt layer on the southeast of Brazil represent a significant increment in the Brazilian share of the global hydrocarbon reserves, which is still the most important energetic matrix. In this scenario, the development of production for these petroleum fields becomes important. One of the main technological challenges posed by these fields is the processing of the associated gas, which contains high amounts of carbon dioxide (CO2). Due to environmental laws, this contaminant must be separated to allow the injection back into the reservoir and/or the gas flow through subsea pipelines. The gas processing plants installed on large vessels comprise facilities that remove CO2 and moisture from natural gas, to prevent hydrate formation and severe corrosion throughout the pipelines, as both gas injection and gas exportation are performed in extreme pressure and temperature conditions. Thus, the accurate knowledge of conditions in which aqueous liquid phases are formed is important to ensure the technical viability and operational safety of these operations. Considering the relevance of this subject and the limitations of published works for the Brazilian pre-salt scenario, this work presents a comprehensive study on the phase equilibrium in systems with hydrocarbons in gas phase with high content of CO2 and traces of water, aiming at developing a model to calculate the dew point of water. The use of a rigorous method based on the associating fluid theory (PCSAFT) has shown to be appropriate to calculate the saturation condition for a large range of pressure and temperature. Based on the experimental data published, the fitting of the binary interaction parameter from the PC-SAFT equation of state was carried out. The resulting model was able to describe the phase behavior of hydrocarbon mixture with composition similar to those found in the Brazilian pre-salt.

abstract: Seeking to address sustainability issues associated with food waste (FW), and fat, oil, and grease (FOG) waste disposal, the City of Mesa commissioned the Biodesign Swette Center for Environmental Biotechnology (BSCEB) at Arizona State University (ASU) to study to the impact of implementing FW/FOG co-digestion at the wastewater treatment plant (WWTP). A key issue for the study was the “souring” of the anaerobic digesters (ADs), which means that the microorganism responsible for organic degradation were deactivated, causing failure of the AD. Several bench-scale reactors soured after the introduction of the FW/FOG feed streams. By comparing measurements from stable with measurements from the souring reactors, I identified two different circumstances responsible for souring events. One set of reactors soured rapidly after the introduction of FW/FOG due to the digester’s hydraulic retention times (HRT) becoming too short for stable operation. A second set of reactors soured after a long period of stability due to steady accumulation of fatty acids (FAs) that depleted bicarbonate alkalinity. FA accumulation was caused by the incomplete hydrolysis/fermentation of feedstock protein, leading to insufficient release of ammonium (NH4+). In contrast, carbohydrates were more rapidly hydrolyzed and fermented to FAs. The most important contribution of my research is that I identified several leading indicators of souring. In all cases of souring, the accumulation of soluble chemical oxygen demand (SCOD) was an early and easily quantified indicator. A shift in effluent FA concentrations from shorter to longer species also portended souring. A reduction in the yield of methane (CH4) per mass of volatile suspended solids removed (VSSR) also identified souring conditions, but its variability prevented the methane yield from providing advanced warning to allow intervention. For the rapidly soured reactors, reduced bicarbonate alkalinity was the most useful warning sign, and an increasing ratio of SCOD to bicarbonate alkalinity was the clearest sign of souring. Because I buffered the slow-souring reactors with calcium carbonate (CaCO3), I could not rely on bicarbonate alkalinity as an indicator, which put a premium on SCOD as the early warning. I implemented two buffering regimes and demonstrated that early and consistent buffering could lead to reactor recovery. / Dissertation/Thesis / Masters Thesis East Asian Languages and Civilizations 2020

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In this study, hydrogen induced cracking (HIC) behavior of welded steels used in petroleum lines under sour petroleum environments was investigated. The testing environment in NACE TM0284-2003 standard was used in order to simulate sour petroleum environment. In order to investigate behavior of welding parameters, used in pipe production, on HIC, welds were done with different line energies. Two different API X-65 steels were used in welding operations. The specimens taken from welded zones were tested in testing environment. The specimens were examined metallographically. Crack lengths were measured with a computer program. The results obtained were discussed in view of metallurgical and welding parameters aspects. The result obtained from this investigation led to a general conclusion that, the metallurgical parameters of steels used in pipe production were more important than welding parameters regarding their effect on HIC. It was shown that the composition and microstructural grain size of steels were in direct relation to HIC.

Baigiamasis darbas atliktas Lietuvos Žemės ūkio universitete 2006 - 2008 metais. Magistro baigiamąjį darbą sudaro įvadas, 3 skyriai, išvados, literatūros sąrašas ir priedai. Darbo apimtis 48 puslapių, juose 25 paveikslai, 8 lentelės, naudotasi 46 literatūros šaltiniais. Tiriamojo darbo tikslas - padidinti plataus vartojimo, kasdienio produkto – rauginto pieno biologinę vertę, panaudojant sausąsias išrūgas, siekiant pagerinti jį vertingomis mineralinėmis medžiagomis, smulkiadispersiniais (unikaliais) baltymais ir angliavandeniu – laktoze. Ištirti sausųjų išrūgų priedo įtaką rauginimo procesui, fizikinėms – cheminėms surauginto pieno savybėms bei jų kitimą laikymo metu. Darbe ištirta sausųjų išrūgų įtaka rauginto pieno savybėms. Įdėjus sausųjų išrūgų padidėja rauginto pieno biologinė vertė, papildant produktą vertingomis mineralinėmis medžiagomis, smulkiadispersiniais (unikaliais) baltymais ir angliavandeniu – laktoze. Sausųjų išrūgų priedas iki 2 % padidina nepakeičiamų amino rūgščių ir mineralinių medžiagų kiekį. Bendras nepakeičiamų amino rūgščių kiekis padidėjo 1068 mg/l, o bendras mineralinių medžiagų kiekis 1727 mg/l (tame kiekyje kalcio padidėjo 220 mg/l, kalio 280 mg/l, natrio 220 mg/l). Nustatyta, kad sausųjų išrūgų priedas iki 2 % nepakeičia tradicinių rauginto pieno juslinių savybių. Gauta, kad mėginiuose suraugintuose su sausųjų išrūgų priedu padidėja LLRR kiekis, šiek tiek sumažėja rūgštinio gelio klampumas, tačiau padidėja išrūgų imobilizavimo galimybės. Su 1 %... [toliau žr. visą tekstą] / Work size - 48 pages, including 25 pictures, 8 tables. List of literature - 46 sources. The beginning of the work -2006 09 01, the end of the work - 2008 05 13. The article analyzes the influence of dry whey on the properties of sour milk, when the dry whey is added. The biological value of sour milk – daily product of wide usage – increases when it is enriched with valuable mineral substances, small-dispersive (unique) albumens and carbohydrate – lactose. The addition of dry whey up to 2 % increases the amount of irreplaceable amine acids and mineral substances. The total amount of irreplaceable amine acids increased by 1068 mg/l, while total amount of mineral substances increased by 1727 mg/l (including increase of calcium by 220 mg/l, potassium – 280 mg/l, sodium 220 mg/l). It was determined that the addition of dry whey up to 2 % does not change the traditional sensitive properties of sour milk. It resulted that when the dry whey was added, LLRR amount increased in the sour samples, the viscosity of the structure of sour gel decreased a little, but the immobilization possibilities of the whey increased. The addition of dry whey of 1 % results in emission of whey in the process of syneresis (in 2 hours) decreased by 6 %, and 2 % - with 17 %. The determined change of physical-chemical indexes during the storage of sour samples (the amount of LLRR in the beginning of storage up to 2 days increased, and later started to decrease). The change of structure of acid gel happens... [to full text]

Tyrimo tikslas. Ištirti ir įvertinti padidintos biologinės vertės maisto produktų (mineralinio vandens „Tichė“ ir rūgpienio, praturtinto konjuguota linolo rūgštimi ir probiotinėmis kultūromis) įtaką 2007/ 2008 m.m. besimokiusių Vilniaus universiteto Medicinos fakulteto II-o kurso Medicinos studijų programos studentų kai kuriems kraujo laboratoriniams rodikliams. Metodai. Vilniaus universiteto ligoninės Santariškių klinikų LDC buvo atlikti kraujo laboratoriniai tyrimai. Siekiant įvertinti vartotų padidintos biologinės vertės maisto produktų galimą poveikį organizmo virškinimo sistemos funkcijoms, buvo sudarytos anketos. Siekiant įvertinti, ar papildomai vartotas maistas turėjo įtakos kraujo biocheminiams rodikliams, buvo atlikti studentų faktinės mitybos tyrimai pagal standartinę 24 valandų apklausos metodiką. Duomenų suvedimui ir analizei panaudotos MICROSOFT EXCEL 2003, SPSS 12,0 programos. Rezultatai ir išvados. Asmenų, kurie vartojo mineralinį vandenį „Tichė“, jonizuoto Ca koncentracija kraujo plazmoje patikimai padidėjo, o kontrolinio bandinio metu, kai buvo vartojamas vien tik šaltinio vanduo, tiek jonizuoto Ca, tiek ir bendra Ca koncentracijos patikimai mažėjo. Tirtieji Medicinos fakulteto studentai pakankamai gerai žino, kiek reikėtų suvartoti geriamo vandens per parą ir supranta jo reikšmę organizmo fiziologinėms funkcijoms. Didžiausia dalis respondentų (net 67,9 proc.) gėrimui vartojo vandentiekio vandenį, tačiau, jeigu vandenį pirko parduotuvėse, 81,8 proc... [toliau žr. visą tekstą] / Purpose of the analysis. To investigate and to evaluate the influence of food products with increased biological value (“Tichė” mineral water and sour milk enriched with conjugated linoleic acid and probiotic cultures) on some laboratory blood test results of students who have attended the second year of Medicine studies at the Faculty of Medicine of Vilnius University in 2007/ 2008. Methods. Laboratory blood examinations were performed in the LDC of Vilnius University Hospital Santariškių Klinikos. In order to evaluate the possible effect of food products with increased biological value on digestive functions of the organism, questionnaires were distributed. In order to find out whether the additionally consumed food had any influence on biochemical blood indicators, actual student nutrition analyses based on standard 24-hour survey methodology were performed. Programs used for data processing and analysis were MICROSOFT EXCEL 2003, and SPSS 12 0. Results and conclusions. The ionized Ca concentration in the blood plasma of persons that were using “Tichė” mineral water increased reliably, while both ionized Ca and overall Ca concentrations were decreasing during a control test when only spring water was used. The examined medical students were sufficiently aware of the daily water amount that should be consumed and understand its significance to the physiological functions of the body. The majority of respondents (67.9 percent) were drinking tap water; however, if the water... [to full text]

The goal is of this project was to identify principles to guide the development of high performance dense film membranes for natural gas sweetening using hydrogen sulfide and carbon dioxide gas mixtures as models under aggressive sour gas feed conditions. To achieve this goal, three objectives were developed to guide this research. The first objective was to study the performance of cellulose acetate (CA) and an advanced crosslinkable polyimide (PDMC) dense film membrane for H₂S separation from natural gas. The second objective was to engineer those polymers to produce membrane materials with superior performance as measured by efficiency, productivity, and plasticization resistance, and the third objective was to determine the separation performance of these engineered membrane materials under more aggressive, realistic natural gas feeds, and to perform a detailed transport analysis of the factors that impact their performance. Work on the first objective showed that in neat CA, penetrant transport is controlled by both the solubility and mobility selectivity, with the former being more dominant, leading to a high overall CO₂/CH₄ (33) and H₂S/CH₄ (35) ideal selectivities. However, in uncrosslinked PDMC, H₂S/CH₄ selectivity favored sorption only, whereas CO₂/CH₄ selectivity favored both mobility and sorption selectivity, leading to a high CO₂/CH₄ (37) but low H₂S/CH₄ (12) ideal selectivities. However, the latter polymer showed more plasticization resistance for CO₂. In the second objective, both materials were engineered. A new technique referred to as “GCV-Modification” was introduced in which cellulose acetate was grafted using vinyltrimethoxysilane (VTMS), then hydrolyzed and condensed to form a polymer network. PDMC was also covalently crosslinked to enhance its performance. GCV-Modified CA showed significant performance improvements for H₂S and CO₂ removal; the permeability of CO₂ and H₂S were found to be 139 and 165 Barrer, respectively, which represented a 30X and 34X increase compared to the pristine CA polymer. The H₂S/CH₄ and CO₂/CH₄ ideal selectivities were found to be 39 and 33, respectively. Crosslinked PDMC showed a higher CO₂/CH₄ selectivity of 38 with a better plasticization resistance for CO₂ and H₂S. In the third objective, these materials were tested under aggressive ternary mixtures of H₂S/CO₂/CH₄ with both vacuum and nonvacuum downstream. Even under aggressive feed conditions, GCV-Modified CA showed better performance vs. PDMC, and it remained were fairly stable, making it a potential candidate for aggressive sour gas separations, not only because of its significantly higher productivity, which will help decrease the surface area needed for separation, thereby reducing operating costs, but also because of the lower cost of the raw material GCV-Modified CA compared to PDMC.

The purpose of this study was to examine the performance of several generic types of organic protective coatings as a corrosion protection method for the interior of subsea pipelines in sour gas media. The sour gas environment was simulated in the laboratory by the use of an Autoclave and the performance of the organic coatings was studied via the use of Electrochemical Impedance Spectroscopy (EIS) and Linear Polarization Resistance (LPR) tests to determine the coatings resistance, capacitance and corrosion behavior before and after the exposure to sour gas environment. The coating degradation and the corrosion products formed were examined by the use of SEM/EDS. The results indicated that both FBE and Novolac Epoxy coatings had excellent adhesion properties and chemical resistance. The Amine-Cured Novolac Epoxy coating exhibited good adhesion properties and chemical resistance. However, the Phenolic Epoxy coating started to degrade over time and corrosion took place under the coating.

Compte tenu que la capacité de panification de l'amidon aigre, amidon de manioc modifié par fermentation et irradiation UV, n'a pas encore été complètement élucidée, l'influence du génotype et les traitements post-récolte sur le pouvoir de panification de l'amidon aigre a été l'objectif de ce travail. 13 génotypes de manioc de Colombie, cultivés à 1000 m. et 1700 m.p.n.m (3 de plaine et 10 d'altitude, respectivement) modifiés par fermentation (0 ou30 jours) et séchage (four ou soleil) ont été étudiés. Les analyses de la taille des granules, la viscosité d'empesage RVA et la viscosité intrinsèque révèlent que les traitements post-récolte ont été les facteurs prépondérants en vue de l'amélioration de la capacité de panification tandis que le facteur génotype a présenté une influence moins importante. Parmi les traitements post-récolte, la fermentation a présenté un effet plus prononcé sur la structure des granules d'amidon, que le séchage au soleil. Cependant, la combinaison de ces deux traitements a été nécessaire pour obtenir une forte capacité de panification. L'effet d'altitude de culture a été mis en évidence lors de la fermentation par des sensibilités différentes trouvées entre les granules de plaine et d'altitude (exocorrosion et endocorrosion, respectivement). Les génotypes d'altitude, donc, ont montré une bonne capacité de panification. Néanmoins, d'autres facteurs entrent en jeu, la teneur en amylose mesurée par DSC a influencé négativement l'expansion de la pâte, probablement en raison de la formation de complexes amylose-lipide. Par conséquent, la combinaison de génotypes de manioc (la teneur en amylose principalement) et les traitements post-récolte sont un élément clé de la capacité de panification de l'amidon aigre. Ces contributions peuvent aider à l'établissement de standards de qualité de l'amidon aigre vis à vis de leur potentielle utilisation dans la fabrication des produits sans-gluten. / The breadmaking ability of sour cassava starch, cassava starch modified by fermentation and UV irradiation, have not been yet fully elucidated. The influence of genotype and postharvest treatments on expansion ability of sour cassava was the objective of this work. Thirteen cassava genotypes have been studied. All genotypes proceeded from Colombia. Two altitudes of origin (1000 m. and 1700 m.a.s.l. refered to respectively as lowland and highland), fermentation treatments (0 or 30 days) and drying treatments (oven or sun) were considered. Analyses of the granule size, RVA pasting behavior and intrinsic viscosity were analysed as indicators of breadmaking ability. Results showed that post-harvest treatments were prevailing factors in improving breadmaking ability while the genotype factors had a smaller influence. Among post-harvest treatments, fermentation had a greater influence than sun-drying on these indicators, in particular on starch granular structure. The combination of both treatments was needed to obtain a high capacity bread. Furthermore, the altitude of origin of cassava genotypes was observed to affect the fermentation process: different sensitivities to fermentation were found between granules of lowland and highland (exocorrosion and endocorrosion, respectively). Highland genotypes showed a better breadmaking ability. Other influencing factor related to genotype was the amylose content measured by DSC: it negatively influenced the expansion of the dough, probably due to the formation of amylose-lipid complex. As a conclusion, the combination of cassava genotypes (mainly amylose content) and post-harvest treatment is key for expansion ability of sour starch. This knowledge is a first, essential step to provide quality standards for sour starch, targeted particularly for use in gluten-free products.