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Mehdi Khiadani - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation and analysis of a new single stage vacuum spray flash desalinator utilising a gas liquid ejector
Journal of Cleaner Production, 2018Co-Authors: Alireza Hosseini Araghi, Mehdi KhiadaniAbstract:Abstract The aim of this research is to investigate the performance and the dynamic thermo-Fluid behaviour of a new vacuum spray flash desalinator. This is the key component of the open water cycle in the discharge thermal energy combined desalination (DTECD) system utilising a gas-liquid ejector (eductor). A down-flow eductor using saline water as a Motive Fluid is proposed for this new single-stage vacuum desalinator. The effects of the temperature and the salinity of Motive Fluid on the performance of eductor are investigated. The exergy efficiency of the system and its components are evaluated. Experimental results indicate that the performance of the proposed desalinator aligns well with the evaporation model. The proposed eductor is also reliable and easy to operate for generating a vacuum as required close to 6 kPa. This pressure is lower than the corresponding saturation pressures of the operating temperature range between 55 °C and 75 °C. The results show that lower vacuum pressure is obtained when the temperature of the Motive Fluid is lower (about 30 °C or less). The eductor was operated using 3% and 3.5% by weight of saline water and the results show that the salinity of the Motive Fluid does not significantly affect the performance of the system. Thus, utilising seawater can be an alternative and cheap option for operating the eductor.
Dariusz Butrymowicz - One of the best experts on this subject based on the ideXlab platform.
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prediction of critical mass rate of flashing carbon dioxide flow in convergent divergent nozzle
Chemical Engineering and Processing, 2019Co-Authors: Wojciech Angielczyk, Jean Marie Seynhaeve, Jerzy Gagan, Yann Bartosiewicz, Dariusz ButrymowiczAbstract:Abstract The prediction of a critical mass flow rate of flashing flow is of crucial importance for many applications in chemical and processing apparatus. One of the most prosperous application is the two-phase ejector as a device with flashing liquid phase as a Motive Fluid and vapour phase as a secondary Fluid. In that case the prediction of critical flashing flow mass flow rate is necessary. A new generalised procedure of the transonic trajectory determination that uses enhanced Possible-Impossible Flow algorithm is proposed. The procedure is much faster than the commonly used Newton Critical Point (NCP) approach. The approach was applied in modelling of carbon dioxide transonic two-phase flow through the convergent-divergent nozzle by means of Homogeneous Equilibrium Model (HEM) and Delayed Equilibrium Model (DEM). These models were used to simulate flows that were experimentally and theoretically investigated in literature. The application of DEM model for determination of the supersonic trajectory part for CO2 flow is a novel contribution provided in the paper. The comparison with literature experimental data revealed that the original closure equations developed for water are improper for CO2 transonic flows, thus the adjusting attempts were demonstrated. It was revealed that the applied Darcy friction factor determination approach significantly influences on the results. Moreover, an effective DEM adjustment is impossible until Lockhart–Martinelli approach is utilised. It was shown that for CO2 case Darcy friction factor calculated by means of Friedel approach is more appropriate than the one calculated by means of the commonly used Lockhart–Martinelli approach. Nevertheless, it was demonstrated that using a frictionless approach would still give better results while adjusting DEM to better approximate the experimental pressure distributions.
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analysis of application of two phase injector in ejector refrigeration systems for isobutane
Applied Thermal Engineering, 2015Co-Authors: Kamil śmierciew, Dariusz Butrymowicz, Roman Kwidzinski, Tomasz PrzybylinskiAbstract:Abstract Two-phase vapour–liquid injectors may be applied as a feeding pump device or as a condensing device in many applications. In these injectors vapour is a Motive Fluid which enthalpy is used to compress and heat a liquid – the secondary Fluid. The model of the cycle operation of the ejection system equipped with two-phase vapour liquid injector as a feeding pump was proposed. Two-Fluid model for the two-phase flow in such injector was proposed in the paper. The model equations were formulated for one-dimensional steady flow. The analysis of the operation if this cycle was presented for isobutane as the working Fluid.
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MODEL OF STEAM-WATER INJECTOR
2015Co-Authors: Dariusz Butrymowicz, R. Matysko, W. Angielczyk, M. Trela, M. BergAbstract:Two-phase steam-water injectors may be applied as a feeding pump device or as a condensing device in many applications. In such injectors steam is a Motive Fluid while cold water is a secondary Fluid. One-dimensional model of two-phase injector has been proposed in the paper. Model is based on two-Fluid model of two-phase flow along with a set of closure equations. The results of calculations have been compared with experimental results showing reasonably good agreement
G. Scott Samuelsen - One of the best experts on this subject based on the ideXlab platform.
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integration of air separation unit with h2 separation membrane reactor in coal based power plant
Volume 4: Cycle Innovations; Electric Power; Industrial and Cogeneration; Manufacturing Materials and Metallurgy, 2006Co-Authors: D J Francuz, A. Verma, G. Scott SamuelsenAbstract:A novel process configuration consisting of integrating the air separation unit with a H2 separation membrane reactor (HSMR) in a coal gasification based coproduction facility with near zero emissions is described. The plant utilizes an air separation unit operating at elevated pressure to produce an Intermediate Pressure (IP) N2 stream in addition to the O2 required by the coal gasifier. The syngas produced by the gasifier after cleanup is supplied to the membrane reactor which produces H2 by shifting the carbon monoxide while simultaneously separating the fy. The IP N2 is used as sweep gas to assist in the separation of the H 2 diffusing across the membrane walls by decreasing the partial pressure of the H2 on the permeate side. The total pressure of gases on the permeate side may thus be increased such that the H2 / N 2 mixture may be fed directly to the gas turbines at the required pressure without requiring cooling and compression of the HT. An added advantage is that the total pressure differential across the membrane wall is reduced. The N2 in the fuel gas functions both as a thermal diluent for reducing the formation of nitrogen oxides and as additional Motive Fluid for expansion in the turbine. The carbon dioxide rich gas (non-permeate) leaving the membrane reactor after catalytic oxidation of the residual combustibles constitutes the carbon capture stream which may be further compressed and pipelined for CO2 sequestration. High purity H2 may be coproduced for export from a portion of the H2-N2 stream leaving the HSMR utilizing a Pressure Swing Adsorption (PSA) unit. The techno-economic advantages of such a coproduction facility are addressed. Copyright © 2006 by ASME.
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integration of air separation unit with h2 separation membrane reactor in coal based power plant
Volume 4: Cycle Innovations; Electric Power; Industrial and Cogeneration; Manufacturing Materials and Metallurgy, 2006Co-Authors: D J Francuz, A. Verma, G. Scott SamuelsenAbstract:A novel process configuration consisting of integrating the air separation unit with a H2 separation membrane reactor (HSMR) in a coal gasification based coproduction facility with near zero emissions is described. The plant utilizes an air separation unit operating at elevated pressure to produce an Intermediate Pressure (IP) N2 stream in addition to the O2 required by the coal gasifier. The syngas produced by the gasifier after cleanup is supplied to the membrane reactor which produces H2 by shifting the carbon monoxide while simultaneously separating the fy. The IP N2 is used as sweep gas to assist in the separation of the H 2 diffusing across the membrane walls by decreasing the partial pressure of the H2 on the permeate side. The total pressure of gases on the permeate side may thus be increased such that the H2 / N 2 mixture may be fed directly to the gas turbines at the required pressure without requiring cooling and compression of the HT. An added advantage is that the total pressure differential across the membrane wall is reduced. The N2 in the fuel gas functions both as a thermal diluent for reducing the formation of nitrogen oxides and as additional Motive Fluid for expansion in the turbine. The carbon dioxide rich gas (non-permeate) leaving the membrane reactor after catalytic oxidation of the residual combustibles constitutes the carbon capture stream which may be further compressed and pipelined for CO2 sequestration. High purity H2 may be coproduced for export from a portion of the H2-N2 stream leaving the HSMR utilizing a Pressure Swing Adsorption (PSA) unit. The techno-economic advantages of such a coproduction facility are addressed. Copyright © 2006 by ASME.
Alireza Hosseini Araghi - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation and analysis of a new single stage vacuum spray flash desalinator utilising a gas liquid ejector
Journal of Cleaner Production, 2018Co-Authors: Alireza Hosseini Araghi, Mehdi KhiadaniAbstract:Abstract The aim of this research is to investigate the performance and the dynamic thermo-Fluid behaviour of a new vacuum spray flash desalinator. This is the key component of the open water cycle in the discharge thermal energy combined desalination (DTECD) system utilising a gas-liquid ejector (eductor). A down-flow eductor using saline water as a Motive Fluid is proposed for this new single-stage vacuum desalinator. The effects of the temperature and the salinity of Motive Fluid on the performance of eductor are investigated. The exergy efficiency of the system and its components are evaluated. Experimental results indicate that the performance of the proposed desalinator aligns well with the evaporation model. The proposed eductor is also reliable and easy to operate for generating a vacuum as required close to 6 kPa. This pressure is lower than the corresponding saturation pressures of the operating temperature range between 55 °C and 75 °C. The results show that lower vacuum pressure is obtained when the temperature of the Motive Fluid is lower (about 30 °C or less). The eductor was operated using 3% and 3.5% by weight of saline water and the results show that the salinity of the Motive Fluid does not significantly affect the performance of the system. Thus, utilising seawater can be an alternative and cheap option for operating the eductor.
Teixeira, Mauricio Broxado De França - One of the best experts on this subject based on the ideXlab platform.
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Hidrodinamica e transferencia de massa em ejetores liquido-gas com escoamento descendente
[s.n.], 2018Co-Authors: Teixeira, Mauricio Broxado De FrançaAbstract:Orientador: Satoshi TobinagaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: O presente trabalho objetiva o estudo dos fenômenos de transferência de massa e quantidade de movimento em um ejetor líquido-gás multiorifício em escoamento descendente, para o caso em que o gás é admitido na câmara de sucção por auto-aspiração, tendo como Fluido primário água e como Fluido secundário o ar atmosférico. O ejetor utilizado nos experimentos tem vazão nominal de projeto de 2,0 m3/h para o Fluido primário e foi construído em acrílico incolor, permitindo assim a visualização dos tipos gerais de escoamentos obtidos. A caracterização hidrodinâmica relacionou os efeitos das variáveis operacionais do ejetor sobre os diferentes tipos de escoamentos observados na câmara de mistura. Foram propostas, ainda, correlações para a predição da capacidade de auto-aspiração de gás. A velocidade do jato de líquido para os três diferentes bicos empregados foi variada na faixa de 1,90 a 13,2 m/s, possibilitando a obtenção de uma razão volumétrica gás-líquido na faixa de 0,10 a 1,60. A pressão absoluta de sucção na linha de admissão de ar foi variada na faixa de 75,0 a 95,0 kPa. O balanço de forças estabelecido no interior do equipamento permitiu o controle da altura da zona de mixing-shock, definindo-se mapas de domínio hidrodinâmico onde ocorrem os escoamentos coaxial e bifásico homogêneo e onde se observa risco de inundação da câmara de sucção. O fenômeno de transferência de massa foi investigado a partir de medidas locais e globais do coeficiente volumétrico de transporte mássico (kla) e da taxa de absorção molar de oxigênio na fase aquosa. A eficiência de transferência padrão (TEpadrão) variou na faixa de 0,08 a 0,40 kg02/(kWh), enquanto a taxa específica de transferência de oxigênio foi de aproximadamente 0,057 kg02/(m3h), valor três vezes superior ao observado em aeradores superficiais aplicados na indústria de processos. A partir dos resultados obtidos foi possível escrever um manual geral de operação para ejetores líquido-gás, bem como uma rotina simplificada de projetoAbstract: This work aimed at studying the mass and momentum transport phenomena of a downstream and gas self-aspirated liquid-gas ejector, in which the Motive Fluid was ordinary tap water and the gas was air at atmospheric pressure. In order to develop the experiments a prototype of a liquid-gas ejector with a rate of 2.0m3/hr was built of transparent perspex, helpful to the pattern flow visualization inside the mixing chamber. Building and assembly procedures concerning the ejector were also discussed. Several experiments were carried out using the small-scale equipment with the purpose of studying the effects of important variables on the pattern of the downstream two-phase flow. Relationships between the variables and the self-aspirated gas flow were proposed. The liquid jet velocity ranged between 1.90 and 13.2 m/sec for three different nozzles, leading to a gas-liquid ratio in the range 1.10 to 1.60. The absolute suction pressure in the gas line was ranged between 75.0 and 95.0 kPa. The balance of forces established inside the ejector has allowed the control of the mixing-shock zone along the mixing chamber. Flow pattern maps were plotted based on hydrodynamic conditions, highlighting the occurance of bubble flow and coaxial flow as well as where there is risk of suction chamber flooding. The mass transfer phenomenon was investigated from the experimental measurements of the local and global volumetric mass transfer coefficient (kla) and from the absorption rate of oxigen in aqueous solutions. The standard transfer efficiency was obtained in the range of 0.08 and 0.40 kg02/(kWhr). The oxygen transfer rate had a value of 0.057 kg02/(m3hr), three times higher than that reported on the industrial turbine aeration units. From the experimental results it was possible to write a general guide to the liquid-gas ejector operation, as well as a practical routine designDoutoradoDoutor em Engenharia de Alimento