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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

Process simulation and assessment of crude oil stabilization unit

Rahmanian, Nejat, Aqar, D.Y., Bin Dainure, M.F., Mujtaba, Iqbal 05 July 2018 (has links)
Yes / Crude oil is an unrefined petroleum composed of wide range of hydrocarbon up to n‐C40+. However, there are also a percentage of light hydrocarbon components present in the mixture. Therefore, to avoid their flashing for safe storage and transportation, the live crude needs to be stabilized beforehand. This paper aims to find the suitable operating conditions to stabilize an incoming live crude feed to maximum true vapor pressure (TVPs) of 12 psia (82.7 kPa) at Terengganu Crude Oil Terminal, Malaysia. The simulation of the process has been conducted by using Aspen HYSYS. The obtained results illustrate that the simulation data are in good agreement with the plant data and in particular for the heavier hydrocarbons. For the lighter components, the simulation results overpredict the plant data, whereas for the heavier components, this trend is reversed. It was found that at the outlet temperature (85–90°C) of hot oil to crude heat exchanger (HX‐220X), the high‐pressure separator (V‐220 A/B) and the low‐pressure separator (V‐230 A/B) had operating pressures of (400–592 kPa) and (165–186 kPa), respectively, and the live crude was successfully stabilized to a TVP of less than 12 psia. The impact of main variables, that is, inlet feed properties, three‐phase separators operating pressure, and preheater train's performance on the product TVP, are also studied. Based on the scenarios analyzed, it can be concluded that the actual water volume (kbbl/day) has greater impact on the heat exchanger's duty; thus, incoming free water to Terengganu Crude Oil Terminal should be less than 19.5 kbbl/day (9.1 vol%) at the normal incoming crude oil flow rate of 195 (kbbl/day).
82

A Model for the PTX Properties of H2O-NaCl

Atkinson, Allen Bradley Jr. 13 August 2002 (has links)
In many geologic environments, fluids have compositions that are approximated by the H₂O-NaCl system. When minerals grow in the presence of such fluids, some of the solution is trapped in the growing mineral as fluid inclusions. The salinity, temperature of homogenization, and pressure of homogenization are required to predict the trapping conditions of the fluid inclusion. In the laboratory the salinity and the temperature of homogenization of the trapped fluid are easily determined however, the pressure of homogenization cannot be determined directly, and must be calculated from an equation of state. A statistical model that relates the vapor pressure of H₂O-NaCl to the fluid temperature and composition has been developed. The model consists of equations that predict the vapor pressure of H₂O-NaCl from the eutectic temperature (-21.2°C) to 1500°C and for all compositions between the pure end-members. The model calculates the vapor pressure based on the composition (wt% NaCl) and the temperature of homogenization, which can be directly obtained from laboratory studies of fluid inclusions. This information in turn can be used to construct the isochore, or line of constant volume, along which the fluid inclusion was trapped. Finally the isochore can be used to determine the temperature and pressure at which the host mineral of the fluid inclusion was trapped. / Master of Science
83

A hydrodynamic evaluation of the Sandia UO₂ equation of state experiment

Smith, Mark Scott January 1981 (has links)
No description available.
84

Design, construction and operation of an automated vapor pressure determination apparatus (I). II, Gas chromatography/mass spectrometry headspace analysis of engine oil, III, Design of a chemically selective layer for ozone detection

Levermore Thorpe, Dianne Marie 12 1900 (has links)
No description available.
85

Equilibrio líquido-vapor de misturas de álcoois superiores contendo 2-propanol, 2-metil-1-propanol e 3-metil-1-butanol / Vapor-liquid equilibrium of mixtures containing the following higher alcohols 2-propanol, 2-methyl-1-proponol and 3-methyl-1-butanol

Dias, Telma Porcina Vilas Boas, 1986- 17 August 2018 (has links)
Orientador: Antonio Jose de Almeida Meirelles / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-17T20:44:23Z (GMT). No. of bitstreams: 1 Dias_TelmaPorcinaVilasBoas_M.pdf: 800597 bytes, checksum: eee5814b7dd33c7fe35806dce5b84d48 (MD5) Previous issue date: 2011 / Resumo: Os álcoois superiores são provenientes, em sua maior parte, de transformações de aminoácidos durante o processo de fermentação. São álcoois com números de átomos de carbono entre três e cinco, como o álcool propílico, álcool amílico e seus isômeros, responsáveis pelo odor de algumas bebidas alcoólicas. Eles estão presentes na composição do óleo fúsel, que é a fração alcoólica menos volátil obtida durante a destilação do etanol. Embora o óleo fúsel seja um dos principais subprodutos da destilação do álcool, não é devidamente aproveitado pelas indústrias. Devido à presença desses álcoois superiores no processo de destilação do etanol, este trabalho tem como objetivo estudar o equilíbrio líquido vapor (ELV) desses componentes. O estudo foi feito com sistemas isobáricos a pressões de 760 e 560 mmHg, formados pelos álcoois superiores 2-propanol, 2-metil-1-propanol e 3-metil-1-butanol. O equipamento empregado na obtenção dos dados de equilíbrio (_ 9 _ 9 _ 9 _: foi um ebuliômetro FISCHER ® e a composição das fases em equilíbrio (líquida e vapor condensado) foi determinada utilizando cromatografia gasosa. Os sistemas estudados foram os binários 3-metil-1-butanol + 2-metil-1-propanol a 760 mmHg, 2-propanol + 3-metil-1-butanol a 760 mmHg e 560 mmHg e o ternário 2-propanol + 3-metil-1-butanol + 2-metil-1-propanol a 760 mmHg e 560 mmHg, procurando cobrir toda a faixa de composição, incluindo os compostos puros. Os dados de ELV obtidos experimentalmente foram submetidos ao teste de consistência termodinâmica. Outra contribuição consistiu na obtenção dos parâmetros de interação binária de modelos de coeficientes de atividade da fase líquida como as equações de Wilson, UNIQUAC e NRTL. Estas equações são comumente usados em simuladores de processos. Para o ajuste de parâmetros e o teste de consistência foi utilizado o simulador Aspen Plus ®. Os testes de consistência termodinâmica confirmaram a boa qualidade dos dados obtidos pelo ebuliômetro FISCHER ® para os sistemas binários estudados. Os modelos de Wilson, NRTL e UNIQUAC mostraram-se adequados na representação do ELV de todos os sistemas estudados, binários e ternários, obtendo-se desvios de temperatura e de composição da fase vapor muito próximos para todos os modelos utilizados / Abstract: The higher alcohols are derived, mainly, from the amino acids changes during the fermentation process. These are alcohols with carbon numbers between three and five, such as propyl alcohol, amyl alcohol and their isomers, responsible for the odor of most alcoholic beverages. They are present in the composition of fusel oil, which is the least volatile alcoholic fraction obtained during the ethanol distillation. Although the fusel oil is one of the main by-products of alcohol distillation, it is not properly harnessed by industry. Due to the presence of higher alcohols in the ethanol distillation process, this work aims at studying the vapor-liquid equilibrium (VLE) of these components. The study was developed with isobaric systems at pressures of 760 and 560 mmHg, formed by higher alcohols 2-propanol, 2-methyl- 1-butanol and 3-methyl-1-butanol. The equipment used in obtaining the equilibrium data (P ¿ T ¿ x ¿ y) was an ebuliometer FISCHER and the composition of the equilibrium phases (liquid and condensed steam) was determined using gas chromatography. The studied systems were the binary 3-methyl-1-butanol + 2- methyl-1-propanol at 760 mmHg, 2-propanol + 3-methyl-1-butanol at 760 mmHg and 560 mmHg and the ternary 2-propanol + 3 - methyl-1-butanol + 2-methyl-1- propanol at 760 mmHg and 560 mmHg, always trying to cover the entire composition range including the pure compounds. The VLE data obtained were experimentally tested for thermodynamic consistency. Another contribution was the binary interaction parameters obtained by adjusting the activity coefficient models of the liquid phase (Wilson, NRTL and UNIQUAC) to the experimental data. These equations are commonly used in process simulators. The Aspen Plus simulator was used to adjust the parameters and to test the consistency of the experimental data. The thermodynamic consistency tests confirmed the good data quality obtained by the FISCHER ebuliometer for the binary systems studied. The models Wilson, NRTL and UNIQUAC proved to be adequate for representing the VLE of all studied systems, binary and ternary ones, and the temperature and vapor composition deviations between experimental and calculated data were low for all the models used / Mestrado / Engenharia de Alimentos / Mestre em Engenharia de Alimentos
86

Fluxos de agua em especie de citro (citrus sinensis L. Osbeck - laranja pera) - Campinas - São Paulo / Water flows in species of citrus (citrus sinensis L. Osbeck - Orange pear) - Campinas - São Paulo - Brazil

Teixeira Filho, Aristoteles de Jesus 04 July 2005 (has links)
Orientador: Jose Teixeira Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-04T06:12:33Z (GMT). No. of bitstreams: 1 TeixeiraFilho_AristotelesdeJesus_D.pdf: 3254132 bytes, checksum: aae8c8f2bd08b359e5b2d2c647e86b0e (MD5) Previous issue date: 2005 / Resumo: As variáveis ecofisiológicas exercem grande influência, não somente no comportamento vegetativo das plantas cultivadas, mas, sobretudo no seu desempenho em relação às características produtivas. Os estudos sobre trocas gasosas têm-se ampliado desde a década de oitenta, dada a sua importância em cultivos tropicais, tal qual, em variedades de citros. Tem-se investigado que os estômatos são o principal ponto de controle do fluxo de água, sendo o déficit de pressão hídrica do ar apontada como a força motora para a transpiração, e a quantidade de água no solo é o fator decisivo para o abastecimento hídrico da planta. Dessa forma, a eficiência do uso da água pela cultura pode ser considerada como uma relação custo-benefício para o aumento da produção dos citros, com o mínimo impacto na reserva hídrica do ecossistema, haja vista que no Brasil, apesar da incidência de períodos de déficits hídricos temporários em várias regiões citrícolas, predomina o cultivo sem irrigação. O Brasil é um dos maiores produtores mundiais de frutas cítricas, destacando-se os Estados: Bahia, Minas Gerais, Rio Grande do Sul, Rio de Janeiro, São Paulo e Sergipe. Com plantios acima de 1.100.000 hectares, os citros têm grande importância comercial no Brasil, sendo São Paulo o maior produtor com aproximadamente 70% da produção nacional. O retorno econômico proveniente deste produto é de grande importância para o crescimento do setor agrícola do país. A partir da safra de 1979-1981, a citricultura brasileira vem ocupando o primeiro lugar em produção dentro da América do Sul. Para tal, o estudo foi conduzido no campo experimental da Faculdade de Engenharia Agrícola (FEAGRI) da Universidade Estadual de Campinas, localizado no município de Campinas, entre as coordenadas geográficas de 22o53¿20¿ de Latitude sul e o meridiano 47o04¿40¿ de Longitude oeste de Greenwich. O experimento foi conduzido em cinco plantas de citros de mesma variedade (Citrus sinensis L. Osbeck), realizando medidas de transpiração, condutância estomática, radiação fotossinteticamente ativa, radiação incidente total e déficit de pressão de vapor saturado. No período considerado observou-se que a maior média diária da transpiração 4,63 mmol.m-2.s-1 na PL4T2 e a menor foi de 1,53 mmol.m-2.s-1 na PL1EVP1. O melhor modelo foi aquele que considerou que resposta da transpiração foliar estar diretamente associado ao déficit de pressão de vapor saturado / Abstract: The variables ecofisiológicas exercise great influence, not only in the vegetative behavior of the cultivated plants, but, above all in your acting in relation to the productive characteristics. The studies on gas exchange have been enlarging since the decade of eighty, given your importance in tropical cultivations, just as, in citrus varieties. Has been investigating that the stomatal is the principal point of control of the flow of water, being the deficit of pressure water of the air appeared as the motive force for the perspiration, and the amount of water in the soil it is the decisive factor for the provisioning water of the plant. In that way, the efficiency of the use of the water for the culture can be considered as a relationship cost-benefit for the increase of the production of the citrus, with the minimum impact in the reservation water of the ecosystem, have seen that in Brazil, in spite of the incidence of periods of deficits temporary waters in several areas citrícolas, the cultivation prevails without irrigation. Brazil is one of the largest world producers of citric fruits, standing out States: Bahia, Minas Gerais, Rio Grande do Sul, Rio de Janeiro, São Paulo and Sergipe. With plantings above 1.100.000 hectares, the citrus have great commercial importance in Brazil, being São Paulo the largest producing with approximately 70% of the national production. The originating from economical return this product is of great importance for the growth of the agricultural section of the country. Starting from the crop of 1979-1981, the Brazilian citricultura is occupying the first place inside in production of South America. For such, the study was lead in the experimental field of the College of Engenharia Agrícola (FEAGRI) of the State University of Campinas, located in the city of Campinas, enters the geographic coordinates of 22o53¿20¿ of south Latitude and the meridian 47o04¿40¿ of Longitude west of Greenwich. The experiment was led in five plants of citrus of same variety (Citrus sinensis L. Osbeck), accomplishing perspiration measures, conductance stomatal, radiation fotossinteticamente activates, total incident radiation and deficit of pressure of saturated vapor. In the considered period it was observed that the largest average daily rate of the perspiration 4.63 mmol.m-2.s-1 in PL4T2 and the smallest was of 1.53 mmol.m-2.s-1 in PL1EVP1. The best model was that that considered that answer of the perspiration to foliate to be directly associated to the deficit of pressure of saturated vapor / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola
87

MICRO-CLIMATE CHARACTERIZATION OF COMFORT MATERIALS : A CLIMATE ANALYSIS OF HIGH RESILIENCE FOAM IN MICRO-CLIMATE CONDITIONS

Siddachary, Ullas January 2022 (has links)
Currently, it is widely recognised that the operational energy consumption of most building types currently outweighs their embodied energy by some margin. However, as we make dramatic increases in energy efficiency the embodied energy of the materials and components that we use will become proportionally larger and may account for a substantial proportion of the energy associated with buildings in the future. The main factor that might contribute to comfort/discomfort perception is the thermal equilibrium caused by the interaction between a person and the interaction of an object.This is easy to demonstrate as an assumption, mainly in situations where almost the whole body is in contact with the object. The main purpose of this work is to determine important parameters that differentiate different materials and develop new way of working with comfort materials (in particular, soft materials like High Resilience foam and High-Density foam) and characterize them based on their response to temperature and humidity. A literature study is performed to gain more knowledge about current state of foam technology and experimental methods are used to obtain analytical data.To characterize the materials, climate chamber is used to evaluate the materials to determine their properties. From the experiment, the key parameters were determined to be Temperature, Humidity, Vapour pressure and Heat Index. These parameters have a significant impact on the comfortability of the material and hence can be used to determine a soft material’s properties and their reaction to certain environments. The most important characteristics such as temperature, humidity, partial water vapour pressure show that HS materials which 400-450mm of PCR coating have much better sweat diffusion which can be attributed to chemical composition of the material and thermal capacity. The most difficult part micro-climate analysis is to accurately represent what is ‘comfortable’, as comfort is subjective but by using these methods of experiments and analysing methods, the characteristics of the materials can be determined, and a conclusion can be drawn. One of the most difficult things in microclimate testing or testing as such is the repetition of equal processes because it requires experience with the device and the complex process to gain comparable data. There are many variables that were not included in this study due to time constraints but can certainly add to the accuracy of the results. The study was conducted only on two materials over a certain period which can be extended for further accuracy.
88

Prediction of Thermodynamic Properties by Structure-Based Group Contribution Approaches

Emami, Fatemesadat 02 September 2008 (has links)
No description available.
89

Selection of Prediction Methods for Thermophysical Properties for Process Modeling and Product Design of Biodiesel Manufacturing

Su, Yung-Chieh 14 July 2011 (has links)
To optimize biodiesel manufacturing, many reported studies have built simulation models to quantify the relationship between operating conditions and process performance. For mass and energy balance simulations, it is essential to know the four fundamental thermophysical properties of the feed oil: liquid density (Ï L), vapor pressure (Pvap), liquid heat capacity (CpL), and heat of vaporization (Î Hvap). Additionally, to characterize the fuel qualities, it is critical to develop quantitative correlations to predict three biodiesel properties, namely, viscosity, cetane number, and flash point. Also, to ensure the operability of biodiesel in cold weather, one needs to quantitatively predict three low-temperature flow properties: cloud point (CP), pour point (PP), and cold filter plugging point (CFPP). This article presents the results from a comprehensive evaluation of the methods for predicting these four essential feed oil properties and six key biodiesel fuel properties. We compare the predictions to reported experimental data and recommend the appropriate prediction methods for each property based on accuracy, consistency, and generality. Of particular significance are (1) our presentation of simple and accurate methods for predicting the six key fuel properties based on the number of carbon atoms and the number of double bonds or the composition of total unsaturated fatty acid methyl esters (FAMEs) and (2) our posting of the Excel spreadsheets for implementing all of the evaluated accurate prediction methods on our group website (www.design.che.vt.edu) for the reader to download without charge. / Master of Science
90

Modellierung PBPK-relevanter Verteilungskoeffizienten organischer Stoffe

Stöckl, Stefanie 06 February 2014 (has links) (PDF)
Drei Verteilungskoeffizienten, die für physiologie-basierte Pharmakokinetik (PBPK)-Modelle relevant sind, wurden mit verschiedenen Ansätzen modelliert. Für den Blut/Luft-Verteilungskoeffizienten wurde ein auf linearen Solvatations-Energie-Beziehungen (LSER) beruhendes Literaturmodell angewendet und diskutiert. Mit einer schematischen Aufteilung des Blutkompartiments in Wasser und einen organischen Teil wurde der Blut/Luft-Verteilungskoeffizient mit einer linearen Regression von anderen Verteilungskoeffizienten vorhergesagt. Zusätzlich wurde ein Fragmentmodell entwickelt. Der Fett/Luft-Verteilungskoeffizient wurde mit dem LSER-Ansatz und mit anderen Verteilungskoeffizienten modelliert. Der Koeffizient Fett/Blut wurde aus den ersten beiden errechnet. Da der inverse dimensionslose Henry-Koeffizient Wasser/Luft-Verteilungskoeffizient bei der Blut/Luft-Modellierung zum Einsatz kommt und dieser aus dem Dampfdruck und der Wasserlöslichkeit gewonnen werden kann, wurde der Dampfdruck ebenfalls modelliert.

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