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A study of slug flow characteristics in large diameter horizontal multiphase pipelinesMaley, Lisa January 1997 (has links)
No description available.
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Desenvolvimento de transmissores de pressão diferencial baseados em sensores piezoresistivos e saída analógica de 4-20 mA. / Development of piezoresistive differential pressure transmitters with analog output of 4-20 mA.Ibarra, Alejandro Rafael Garcia 20 May 2014 (has links)
Este projeto de pesquisa apresenta o desenvolvimento de protótipos de transmissores industriais de pressão do tipo diferencial piezoresistivo com saída analógica a dois fios 4-20 mA. Os dispositivos usam um DSSP (processador digital de sinal do sensor) para realizar compensação térmica nas temperaturas de 0°C até 80°C e a calibração de pressão diferencial na faixa de 0-25 bard e de pressão de linha de 0-7 barg. Os transmissores permitem a leitura de diversas variáveis industriais: pressão diferencial, pressão relativa e pressão absoluta em fluidos. Os transmissores têm um TEB (total error band) menor que 0,15 de porcentagem de escala plena. A saída analógica dos transmissores diferenciais de pressão é caracterizada utilizando como base normas internacionais BS (British Standards). Os parâmetros avaliados nos transmissores de pressão são: a exatidão, o coeficiente térmico do offset, o coeficiente térmico do span, o total error band, e os desvios no tempo a curto e longo prazo. Esse trabalho é resultado da parceria dada entre o Laboratório de Sistemas Integráveis da Escola Politécnica da Universidade de São Paulo (LSI/EPUSP) e a empresa MEMS Microssistemas Integrados Híbridos de Pressão. / This research project presents the prototypes development of piezoresistive differential pressure transmitters with analog two-wire output of 4-20 mA. The devices use a DSSP (Digital Signal Processor Sensor) to achieve temperature compensation at temperatures from 0°C to 80°C and differential pressure calibration range from 0 bard to 25 bard and line pressure range from 0 barg to 7 barg. The transmitters measure several industrial variables: differential pressure, relative pressure and absolute pressure at fluids. The transmitters have a TEB (total error band) less than 0.15 percent of full scale. The analog output of the differential pressure transmitters is characterized using British Standards-BS. The parameters evaluated in the pressure transmitters are: the accuracy, the thermal coefficient of the offset, the thermal coefficient of the span, the total error band, the start-up drift and long-term drift. This work is the result of the academic and technological partnership between the Laboratory of Integrated Systems of the Polytechnic School of the University of São Paulo (LSI / EPUSP) and the MEMS company - Microssistemas Integrados Híbridos de Pressão Ltda.
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Desenvolvimento de transmissores de pressão diferencial baseados em sensores piezoresistivos e saída analógica de 4-20 mA. / Development of piezoresistive differential pressure transmitters with analog output of 4-20 mA.Alejandro Rafael Garcia Ibarra 20 May 2014 (has links)
Este projeto de pesquisa apresenta o desenvolvimento de protótipos de transmissores industriais de pressão do tipo diferencial piezoresistivo com saída analógica a dois fios 4-20 mA. Os dispositivos usam um DSSP (processador digital de sinal do sensor) para realizar compensação térmica nas temperaturas de 0°C até 80°C e a calibração de pressão diferencial na faixa de 0-25 bard e de pressão de linha de 0-7 barg. Os transmissores permitem a leitura de diversas variáveis industriais: pressão diferencial, pressão relativa e pressão absoluta em fluidos. Os transmissores têm um TEB (total error band) menor que 0,15 de porcentagem de escala plena. A saída analógica dos transmissores diferenciais de pressão é caracterizada utilizando como base normas internacionais BS (British Standards). Os parâmetros avaliados nos transmissores de pressão são: a exatidão, o coeficiente térmico do offset, o coeficiente térmico do span, o total error band, e os desvios no tempo a curto e longo prazo. Esse trabalho é resultado da parceria dada entre o Laboratório de Sistemas Integráveis da Escola Politécnica da Universidade de São Paulo (LSI/EPUSP) e a empresa MEMS Microssistemas Integrados Híbridos de Pressão. / This research project presents the prototypes development of piezoresistive differential pressure transmitters with analog two-wire output of 4-20 mA. The devices use a DSSP (Digital Signal Processor Sensor) to achieve temperature compensation at temperatures from 0°C to 80°C and differential pressure calibration range from 0 bard to 25 bard and line pressure range from 0 barg to 7 barg. The transmitters measure several industrial variables: differential pressure, relative pressure and absolute pressure at fluids. The transmitters have a TEB (total error band) less than 0.15 percent of full scale. The analog output of the differential pressure transmitters is characterized using British Standards-BS. The parameters evaluated in the pressure transmitters are: the accuracy, the thermal coefficient of the offset, the thermal coefficient of the span, the total error band, the start-up drift and long-term drift. This work is the result of the academic and technological partnership between the Laboratory of Integrated Systems of the Polytechnic School of the University of São Paulo (LSI / EPUSP) and the MEMS company - Microssistemas Integrados Híbridos de Pressão Ltda.
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Differenstrycksregulatorer : En studie om hydronisk reglering av radiatorsystem med hjälp av differenstrycksregulatorerNilsson-Böös, Viktor January 2016 (has links)
The purpose of this work was to investigate in which types of systems where use of differential pressure controllers is possible. And to analyze which success factors using of differential pressure controllers can provide. The work was done with the help of a literature review and discussions with energy consultants at the company FVB Sweden AB. This work does not assume any specific case, but treat scenarios that could occur in reality. There are three main scenarios created to demonstrate the function and importance of differential pressure controllers in a heating system. These scenarios treat cases where one pump is supplying both homes and businesses, when buildings will be built in stages and when the pump supplies a group of properties comprising both one-pipe and two-pipe systems. The study has shown that in all three scenarios imbalance in flow will occur in the heating system, this is reported under the chapter result in the report. In cases where the problem is imbalance of flows, the problem can be solved by installing only a static control valve on the outgoing return line from the property. Financial calculations carried out in this work. These calculations are showing what the additional cost will be for a differential pressure controller, compared to a static control valve. Calculations that show the cost savings that can be made when installing a differential pressure regulator has also been done. The conclusion of this work is that in all three scenarios presented in the results section, a differential pressure controller should be installed to provide the heating system with a balanced flow. Although it is a more expensive alternative, cost savings can be achieved, which justifies the installation of a differential pressure controller in the heating system. / Syftet med detta arbete var att undersöka i vilka typer av systemlösningar som användning av differenstrycksregulatorer är möjlig, samt att undersöka vilka framgångsfaktorer som användning av differenstryckregulatorer kan ge. Arbetet har genomförts med hjälp av en litteraturstudie och samtal med energikonsulter på företaget FVB Sverige AB. Detta arbete utgår inte från något specifikt fall, utan behandlar scenarion som skulle kunna uppstå i verkligheten. Det är främst tre scenarion som skapats för att kunna visa differenstryckregulatorers funktion och betydelse i ett värmesystem. Dessa scenarion är då en (1) pump försörjer både bostäder och verksamheter, när fastigheter skall byggas i etapper samt när en (1) pump försörjer en grupp byggnader som har både ett- och tvårörssystem. Studien har visat att det kommer i samtliga tre scenarion uppstå obalans i värmesystemet, detta redovisas under kapitlet resultat i rapporten. I de fall där obalans i flöden finns kan problemet lösas med att endast installera en statisk stamventil på utgående returledning från fastigheten. Ekonomiska beräkningar har även genomförts i detta arbete. Dessa beräkningar visar på vad merkostnaden blir för en differenstrycksregulator, jämfört med endast en stamventil. Det har även genomförts beräkningar som visar vilka kostnadsbesparningar som kan göras vid installation av en differenstryckregulator. Sammanfattningsvis blir slutsatsen av detta arbete att i samtliga tre scenarion som redovisas i resultatkapitlet, bör en differenstryckregulator installeras för att undvika obalans i systemen. Trots att det är ett dyrare alternativ kan kostnadsbesparingar åstadkommas, vilket motiverar en installation av en differenstryckregulator i värmesystemet.
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Low differential pressure and multiphase flow measurements by means of differential pressure devicesJusto, Hernandez Ruiz, 15 November 2004 (has links)
The response of slotted plate, Venturi meter and standard orifice to the presence of two phase, three phase and low differential flows was investigated. Two mixtures (air-water and air-oil) were used in the two-phase analysis while a mixture of air, water and oil was employed in the three-phase case. Due to the high gas void fraction (α>0.9), the mixture was considered wet gas. A slotted plate was utilized in the low differential pressure analysis and the discharge coefficient behavior was analyzed. Assuming homogeneous flow, an equation with two unknowns was obtained for the multi-phase flow analysis. An empirical relation and the differential response of the meters were used to estimate the variables involved in the equation. Good performance in the gas mass flow rate estimation was exhibited by the slotted and standard plates for the air-water flow, while poor results were obtained for the air-oil and air-water oil flows. The performance of all the flow meter tested in the analysis improved for differential pressures greater than 24.9 kPa (100 in_H2O). Due to the tendency to a zero value for the liquid flow, the error of the estimation reached values of more than 500% at high qualities and low differential pressures. Air-oil and air-water-oil flows show that liquid viscosity influences the response of the differential pressure meters. The best results for high liquid viscosity were obtained in the Venturi meter using the recovery pressure for the gas flow estimation at differential pressures greater than 24.9 kPa (100 in_H2O). A constant coefficient Cd was used for the low differential pressure analysis and results did show that for differential pressure less than 1.24 kPa (5 inH2O) density changes are less than 1% making possible the incompressible flow assumption. The average of the computed coefficients is the value of Cd.
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Low differential pressure and multiphase flow measurements by means of differential pressure devicesJusto, Hernandez Ruiz, 15 November 2004 (has links)
The response of slotted plate, Venturi meter and standard orifice to the presence of two phase, three phase and low differential flows was investigated. Two mixtures (air-water and air-oil) were used in the two-phase analysis while a mixture of air, water and oil was employed in the three-phase case. Due to the high gas void fraction (α>0.9), the mixture was considered wet gas. A slotted plate was utilized in the low differential pressure analysis and the discharge coefficient behavior was analyzed. Assuming homogeneous flow, an equation with two unknowns was obtained for the multi-phase flow analysis. An empirical relation and the differential response of the meters were used to estimate the variables involved in the equation. Good performance in the gas mass flow rate estimation was exhibited by the slotted and standard plates for the air-water flow, while poor results were obtained for the air-oil and air-water oil flows. The performance of all the flow meter tested in the analysis improved for differential pressures greater than 24.9 kPa (100 in_H2O). Due to the tendency to a zero value for the liquid flow, the error of the estimation reached values of more than 500% at high qualities and low differential pressures. Air-oil and air-water-oil flows show that liquid viscosity influences the response of the differential pressure meters. The best results for high liquid viscosity were obtained in the Venturi meter using the recovery pressure for the gas flow estimation at differential pressures greater than 24.9 kPa (100 in_H2O). A constant coefficient Cd was used for the low differential pressure analysis and results did show that for differential pressure less than 1.24 kPa (5 inH2O) density changes are less than 1% making possible the incompressible flow assumption. The average of the computed coefficients is the value of Cd.
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Möjligheter till ökad driftsäkerhet och kostnadseffektivitet i fjärrvärmenät : En simulerings- och optimeringsstudie på Kalmar Energi / Possibilities for increased reliability and cost-effectivness in district heating networks : A simulation and optimization study at Kalmar EnergiTorstensson, Carl, Nordborg, Daniel January 2019 (has links)
Since district heating is the most common way of space heatingin Sweden, continual improvements of theefficiency of production and distribution of district heating is crucial. The purposeof this report is therefore to, using Kalmar Energi as an example, study how the production and distribution of district heating is affected by introducing a bypass pipeat a critical point in the network, and to investigate howcost efficiency might be achieved. To fulfill this task, the network simulation software NetSim and the cost optimizing software MODEST was used. Most ofthe heat in the district heating network in Kalmar comesfrom the bio-fueled combined heat and power plant Moskogen and the top load production plantDraken covers the top load when the heat from Moskogen is not enoughto fulfill the heating demand. However, the studied scenario does not represent normal operationbut a temporary solution for when Draken and its circulation pumps for some reason cannot be used.In that scenario, all heat in the city mustbe delivered using the bypass pipeor usingthe two smaller reserve production plantsLindsdal and Dvärgen. The simulations performed in NetSim consist of three primary cases; one reference modelwhich represents the currentsituation, one model with only Moskogenand the bypass and one model with Moskogen, bypass, Lindsdal and Dvärgen. To study the possibility for improvements of the network further simulations were performed with measures like new circulation pumps, upgradeto bigger pipes and addition of new pipes. The optimization in MODEST also consist of three cases; normaloperation, operation using the bypassand possible benefits ofusing RME instead of oil in reserve plants. The simulations in NetSimshows that the bypass pipe enables fulfillment of the heating demand of Kalmar without the use ofDraken or otherreserveproduction plantsdown to an outside temperature around 1°C.If the reserve units in the periphery parts of the city are used, the bypass of Draken enables fulfillmentof the heating demand until an outside temperature of approximately -3°C. The limiting factorsare mainlycirculationpump capacity and the differential pressure. If a higher supply temperature than normal is usedor newcirculationpumps and bigger pipes are introduced, a working network can be achieved for loweroutsidetemperatures. However, a highersupply temperature means higherheatlosses and no additional electricity production and a new pumping station just to handle a worst-case scenario is most likely not economically feasible. New pipes connecting areas with high and low differential pressures was also found to improve the system, but might not be profitable in the short term. If the city is expected to expand in the certain areas that the new pipesweretested, the new pipes might become amore feasiblemeasurein the future.The optimizing in MODEST shows that from a cost minimizing perspective, it is optimal to use the biomass-fueled combined heat and power plant Moskogenas much as possibleand to cover the remaining heat demand using wood powderboilersand if necessary, oilboilers.It is also evident thatregardless ofthe bypass beingused or not, it is always more profitable to lower the electricity production of Moskogen in favor of heat production during periods when the electricity price is low or whentheuse of oilboilerswould otherwise be needed.This measure also lowers the amount ofcarbon dioxideemissionsfor the systemwith up to 250 tons/yearsince oil use can be exchanged for biomass use.An alternative way of eliminating carbon dioxide emissionsis to replace the oilfuelwith a renewable fuel like RME. However, this would be associated with higher costs for Kalmar Energi, since RME is currently more expensive per MWh than the oil that is currentlyused. / Med tanke på att fjärrvärme är den vanligaste uppvärmningsprincipen i Sverige är arbete med att förbättra effektiviteten och pålitligheten vid produktion och distribution av värme ett ständigt aktuellt ämne. Syftet med detta arbete är därför att med Kalmar Energi som exempel undersöka hur produktion och distribution av fjärrvärme påverkas av att en förbikoppling av en kritisk sektion har byggts samt att identifiera hur kostnadsoptimal drift av fjärrvärmenätet bör ske. För att uppnå detta har nätverkssimuleringsprogrammet NetSim och kostnadsoptimeringsprogrammet MODEST använts. Majoriteten av värmen i Kalmars fjärrvärmenät kommer från det bioeldade kraftvärmeverket Moskogen. Värmeverket Draken täcker under normal drift upp när Moskogens effekt inte räcker till för att uppfylla värmeefterfrågan. Scenariot som framförallt har studerats representerar dock inte normal drift utan utgör en tillfällig lösning för perioder när värmeverket Draken med tillhörande pumpar av någon anledning inte är tillgängliga. All Kalmars fjärrvärme måste i detta läge levereras från Moskogen via den nybyggda förbikopplingen eller med hjälp av de två mindre reservanläggningarna Lindsdal och Dvärgen. De simuleringar som gjorts i NetSim består av tre primära fall; en referensmodell som illustrerar nuläget, en modell med endast Moskogen via förbikopplingen samt en modell med Moskogen via förbikopplingen i kombination med Dvärgen och Lindsdal. För att studera förbättringsmöjligheter i systemet genomfördes även simuleringar på hur förändringar så som nya pumpar och utbyte av gamla rör påverkar systemet. Arbetet i MODEST består också av tre olika delar; normal drift, drift vid användning av förbikopplingen samt nyttan med ett bränslebyte från olja till RME. För normal drift och förbikopplingsdrift utvärderas lönsamheten med att minska elproduktionen och därmed få ut mer värme till fjärrvärmenätet. Simuleringarna i NetSim visar att Moskogen tack vare förbikopplingen ensam kan uppfylla Kalmars värmebehov ner till utomhustemperaturer kring 1 °C. Vid användning av reservanläggningarna i kombination med förbikopplingen kan värmebehovet i dagsläget uppfyllas fullständigt ner till utomhustemperaturer kring -3 °C. De begränsande faktorerna för nätet är framförallt kapacitet hos cirkulationspumpar och differenstryck. Om högre framledningstemperatur används eller om nya cirkulationspumpar införs och begränsande rör görs större kan ett väl fungerande system fås utan Draken även vid lägre utomhustemperaturer. Värt att notera är dock att höjd framledningstemperatur ökar värmeförlusterna i nätet samt att införskaffandet av nya pumpar endast för att hantera ett reservfall bedöms bli dyrt. Nya rör som kopplar samman områden med höga och låga differenstryck förbättrar också systemet men det bedöms på kort sikt inte vara lönsamt att implementera men kan kanske bli aktuellt i samband med framtida expansion av staden. Optimeringen av driften i MODEST visar att det ur produktionskostnadsperspektiv är optimalt att använda det bioeldade kraftvärmeverket Moskogen så mycket som möjligt och sedan täcka upp med träpulver och därefter olja när det behövs. Optimeringen visar också att det både vid utnyttjande av förbikopplingen och vid normal drift är ekonomiskt lönsamt att minska på elproduktionen i Moskogen till fördel för ökad värmeproduktion under perioder när elpriset är lågt eller när olja annars måste användas för värmeproduktion. Denna åtgärd minskar även utsläppen av fossil koldioxid med upp till 250 ton koldioxid per år eftersom oljeanvändning kan ersättas med Moskogens biobränsle. Ett alternativt sätt att eliminera utsläpp av fossil koldioxid vore att ersätta oljan med ett förnybart alternativ, exempelvis RME. Detta medför dock i Kalmars fall att den årliga driftskostnaden ökar med 179 miljoner SEK per år eftersom RME i dagsläget är dyrare per MWh än den olja som idag används.
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Hydrogen cryosorption of micro-structured carbon materialsTeng, Xiao January 2017 (has links)
In comparison with the high-pressure adsorption at room temperature, hydrogen adsorption at cryogenic temperatures can be significantly improved at low pressures, which has great potential for prospective mobile applications. In this study, a differential pressure based manometry system was designed and constructed for fast analysing hydrogen adsorption uptakes of sorbents up to a maximum of 10 wt% at 77 K and up to 11 bar. The safety design of the system in compliance with European ATEX directives (Zone 2) for explosive atmospheres was discussed in detail, together with additional pneumatic systems for remote control of the experiments. A thorough error analysis of related experimental tests was also performed. Common carbon sorbents, including several Norit branded activated carbons and graphene nanoplatelets (GNPs) with various surface areas, were characterised for their pore structures. The structural differences among GPNs of different surface areas were also studied. The hydrogen adsorption isotherms of these sorbents, examined in the newly-built manometry system, were further analysed and discussed with reference to the assessed microstructural properties. The carbonisation processes of plasma carbons from the microwave splitting of methane, and biochars from the pyrolysis of Miscanthus, were intensively studied primarily based on Raman spectroscopy, in conjunction with other characterisation techniques such as XRD, FTIR and XPS, for exploring the formation of graphitic structures and crystallinity under various conditions. Two selected types of carbons, the activated carbon AC Norit GSX with a specific surface areas of 875 m2/g and the graphene nanoplates with a specific surface area of 700 m2/g, were decorated with palladium nanoparticles in different compositions. The growth and distribution of doped palladium particles in the carbon substrates were studied, and their effects on porous properties and microstructures of the sorbents were also reviewed. Hydrogen adsorption tests of the decorated carbons were further conducted and discussed, to explore the potential effects of Pd contents on the adsorption kinetics and hydrogen absolute uptakes.
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[en] INFLUENCE OF THE OPERATION PRESSURE ON THE PERFORMANCE OF A DIFFERENCIAL PRESSURE TRANSMITTER: A METROLOGICAL ANALYSIS / [pt] INFLUÊNCIA DA PRESSÃO DE OPERAÇÃO NO DESEMPENHO DE TRANSMISSORES DIFERENCIAIS DE PRESSÃO: UMA ANÁLISE METROLÓGICALUIZ ALBERTO DI SALVIO 28 October 2008 (has links)
[pt] Nesta dissertação é realizada uma análise experimental da
influência da pressão estática na medição de pressão
diferencial com transmissores eletrônicos, dotados de
sensores capacitivos ou sensores de silício ressonante,
cuja tecnologia é amplamente difundida nos dias atuais por
serem de elevada repetitividade, reprodutibilidade,
exatidão e baixa histerese. A medição de pressão
diferencial é amplamente utilizada na indústria de
Petróleo, com o objetivo de medição de vazão,
nível, entupimento de filtros e medição de interface óleo
água. A calibração dos transmissores de pressão diferencial
é feita no país a pressão atmosférica, não se
preocupando com a influência da pressão estática do
processo sobre seu desempenho. Como sua principal
contribuição, o trabalho apresenta uma metodologia inovadora
ainda não disponível no país de calibração de transmissores
de pressão diferencial na pressão de operação, melhorando a
confiabilidade e a incerteza das medições de
vazão de líquidos e gases nas indústrias em geral. As
faixas estudadas de pressão estática (0 a 20000 KPa) e
diferencial (40 a 250 KPa), atendem a utilização interna
da área de produção e exploração da Petrobras. A simples
substituição da máquina de ensaio e seus instrumentos é
suficiente para a calibração em uma faixa mais ampla,
utilizando-se da mesma metodologia. Para alcançar os
resultados, um dispositivo de amplificação de pressão foi
desenvolvido neste estudo e utilizado em cada
extremidade do transmissor de pressão, para aumentar a
pressão desde valores próximos da atmosférica, que podem
ser medidos com boa exatidão e repetitividade,
até sua pressão de operação. Durante sua utilização, a
pressão diferencial em suas extremidades é deduzida a
partir dos valores medidos próximos da pressão
atmosférica e do fator de amplificação. A incerteza dos
resultados foi estimada e a metodologia foi utilizada para
mostrar que a curva de calibração de um transmissor
de pressão varia com sua pressão de operação. / [en] This paper deals with an experimental analysis of the
static pressure
influence upon the measurement of the differential
pressure. Using capacitive or
silicon resonator transducers, the electronic transmitters
used in the experiment
are thoroughly diffused nowadays due to their
repetitiveness, reproducibility,
accuracy and low hysteresis. The measurement of the
differential pressure is
widely employed in the petrol industry for determining the
flow rate, level,
blockage of filters and the oil-water interface. The
calibration of the differential
pressure transmitters is made in Brazil at atmospheric
pressure, since there is little
concern about the static pressure influence on the
transducer performance. As a
main contribution, this study presents a calibration
methodology of differential
pressure transmitters, still unavailable in the country,
increasing its reliability and
reducing the uncertainty of measuring the flow of liquid or
gaseous substances.
The ranges of the studied static pressure (from 0 to 20000
KPa) and differential
pressure (from 40 to 250 KPa) cover Petrobras production
and exploration
operating conditions. The same methodology can be applied
to wider ranges, by
properly sizing the calibrating device and the related
instruments. To achieve the
results, a pressure amplification device was developed and
used at each port of the
pressure transmitter. A methodology was also developed in
this study to
determine the amplification factor from near atmospheric
values, which can be
measured very accurately, up to the operating pressure of
the transmitter. Thus,
during the calibration of a pressure transmitter, the
pressure differential at the
transmitter ports is deduced from the measured value at
nearly atmospheric
pressure and the amplification factor. The uncertainty of
the results were
estimated and the methodology was used for the calibration
of a pressure
transmitter, showing that its calibrating curve varies with
the operating pressure.
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[en] DEVELOPMENT OF OPTICAL FIBER TRANSDUCERS FOR INTELLIGENT WELL COMPLETION / [pt] DESENVOLVIMENTO DE TRANSDUTORES A FIBRA ÓPTICA PARA COMPLETAÇÃO INTELIGENTE DE POÇOSROBERTH WALDO ANGULO LLERENA 30 December 2004 (has links)
[pt] O setor de petróleo e gás apresenta diversas oportunidades
de aplicação para os sensores a fibra óptica. Algumas
características inerentes às fibras ópticas, como baixo
peso, flexibilidade, longa distância de transmissão, baixa
reatividade do material, isolamento elétrico, imunidade
eletromagnética e alta capacidade de multiplexação, podem
ser determinantes em diversas situações, seja nos segmentos
de exploração, transporte, refino ou distribuição. As
principais operadoras internacionais do setor identificaram
a tecnologia de Sensores a Fibra Óptica como elemento chave
para viabilizar, com toda a funcionalidade esperada, a
instalação de sistemas de completação inteligente de poços
de petróleo (produção ou injeção). O sensoriamento do poço
permite obter, a qualquer momento, informações precisas
sobre diversas grandezas, entre outras a pressão,
temperatura, vazão, pH ou mesmo a posição de válvulas que
controlam o fluxo através do poço. A monitoração em tempo
real do poço é parte da estratégia de automação do processo
de produção do campo de petróleo. Esta é uma tendência que
no futuro próximo aponta para a exploração de campos de
petróleo inteligentes, onde a produção por vários poços de
um mesmo reservatório realizase de forma otimizada e
automatizada, reduzindo custos, e aumentando fatores de
recuperação das reservas de hidrocarbonetos fósseis. O
presente trabalho se insere neste contexto, e apresenta a
concepção, desenvolvimento e resultados de testes de dois
protótipos de transdutores de fundo do poço para integrar
um sistema de completação inteligente baseado na tecnologia
de sensoriamento utilizando redes de Bragg em fibras
ópticas. O primeiro deles destina-se à medida da pressão
diferencial num sensor de vazão do tipo Venturi. Resultados
de testes com protótipos do transdutor demonstraram que ele
pode operar numa faixa de mais ou menos 5 bar de pressão diferencial,
sob pressões médias de até 21 MPa e temperaturas de 90
graus Celsius com resolução de 0,06 por cento do fundo de escala. O segundo
transdutor desenvolvido, aplica-se à medida da posição de
abertura e fechamento de uma válvula controladora de fluxo
tipo camisa deslizante (sliding sleeves). Duas técnicas
foram investigadas. A primeira delas, para aplicações mais
gerais, baseia-se no uso de atuadores magnetoestrictivos. A
segunda procurou atender a um projeto específico para este
tipo de válvula, em cuja concepção utiliza-se uma mola
elástica para exercer a força de restituição contra um
atuador hidráulico. Neste caso, optou-se por desenvolver
uma célula de carga instrumentada com redes de Bragg. Nos
testes realizados foram obtidos resultados satisfatórios em
termos de sensibilidade e resolução, tendo-se chegado para
esta última a valores próximos de 0,03 mm num curso de 70
mm (0,04 por cento do fundo de escala). / [en] Optical fibers are finding a growing range of new
applications in the petroleum industry, which include, not
only those already well established in telecommunications,
but also in novel sensing technologies. Possibility of dense
multiplexing, continuous distributed measurements, long
distances between measurement points and electronic
circuits, and explosion risk free, are some of the
characteristics shared by different types of optical fiber
sensors. The major global oil and gas operators and service
companies have elected optical fiber sensing as one of the
key enablers to implement with all the expected
functionality and reliability the novel technology of
intelligent well completion. Continuous well monitoring
allows the operator to access, at any time during the well
life, important information regarding different process
variables, such as pressure, temperature, flow-rate, pH, or
even the position of sliding sleeves valves that control
the flow through the well. This is part of the automation
strategy to optimize production in the whole reservoir, a
technological trend that points towards the concept of an
intelligent oil field and that, in the near future, will be
applied to the integrated management of production from
several wells in the same reservoir, contributing to reduce
intervention costs, and increasing recovery factors of
fossil hydro-carbon reserves. The present work is inserted
in this context, and reports the conception, development
and results of tests conducted with prototypes of two
different optical fiber transducers to be integrated in an
intelligent well completion system. The first one is a
Bragg grating differential pressure transducer, which has
been developed to measure pressure drop across a Venturi
flow-meter inserted in the production tubing. Test results
with prototypes have demonstrated that the transducer may
be applied to measure differential pressures in the range
of more or less 5 bar, under static (average) pressures up to 21 MPa
and temperatures below 90 Celsius Degree, with 0.06 percent full-scale
resolution. The second development is a displacement
transducer applied to measure the opening position of
sliding sleeves valves. Two different measurement
principles were investigated. The first, intended to
general applications of displacement measurements, relied
on the use of magnetostrictive actuators and fiber Bragg
grating sensors. The second displacement transducer applies
to a specific type of valve, which employs a mechanical
spring to provide recovery forces to a hydraulic actuator.
The proposed solution was based on the use of a load cell
instrumented with fiber Bragg gratings. Tests results
demonstrated that the prototype transducer was capable of
resolving changes in displacement as lower as 0.03 mm in a
full-range of 70 mm, approximately 0.04 percent full-scale
resolution.
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