Holdup
Mostrando 1-12 de 57 artigos, teses e dissertações.
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1. Liquid-phase RTD studies in a flotation column: an analysis between tanks-in-series and axial dispersion models
Abstract The objective of the present study is to evaluate the fluid dynamics of a flotation column (2" in diameter and 6 m in height) based on gas hold-up measurements and, in particular, by applying the liquid-phase RTD (residence time distribution) technique. Additionally, a comparative study is performed between different methodologies used to determine
REM, Int. Eng. J.. Publicado em: 2021-01
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2. SIMULATION AND EXPERIMENTAL INVESTIGATION OF POWER CONSUMPTION, GAS DISPERSION AND MASS TRANSFER COEFFICIENT IN A MULTI-PHASE STIRRED BIOREACTOR
Abstract Bio-oxidation leaching of refractory gold concentrate was carried out in a typical gas-liquid-solid three-phase stirred bioreactor. The bacteria, which adhered to solid particle surfaces and spread over the liquid phase, require sufficient oxygen and nutrient of carbon and nitrogen, and then the mass transfer rate should be considered. However, the
Braz. J. Chem. Eng.. Publicado em: 13/01/2020
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3. Effects of miniemulsion operation conditions on the immobilization of BSA onto PMMA nanoparticles
Abstract Polymer nanoparticles have been widely used in many biomedical applications, constituting a major incentive for immobilization of proteins. Poly(methyl methacrylate) nanoparticles were synthesized through miniemulsion polymerizations and used as supports for bovine serum albumin immobilization. Particularly, the effects of surfactant type (anionic s
Polímeros. Publicado em: 04/11/2019
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4. Hydrodynamics of an external-loop airlift reactor with inserted membrane
Abstract The objective of this study was to investigate the hydrodynamics of an external-loop airlift membrane reactor (ELAMR). The ELAMR was operated in two modes: without (mode A) and with bubbles in the downcomer (mode B), depending on the liquid level in the gas separator. The influence of the gas distributor’s geometry and various alcohol solutions on
Braz. J. Chem. Eng.. Publicado em: 2017-04
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5. Investigation of Copper Extraction from Aqueous Sulfate Solution in a Rotating Disc Contactor
The extraction of copper from aqueous sulfate solution with new extractant Cupromex-3302 (active substance is the 5-nonylsalicylaldoxime) using a rotating disc contactor (RDC) was investigated. It was observed from batch experiments that the best results were obtained with the initial aqueous pH and concentration of Cupromex-3302 of 1.9 and 10% (v/v) respect
J. Braz. Chem. Soc.. Publicado em: 2016-05
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6. SOLID HOLDUP AND CIRCULATION RATE IN A LIQUID-SOLID CIRCULATING FLUIDIZED BED WITH VISCOUS LIQUID MEDIUM
Abstract Experiments were conducted in a liquid-solid circulating fluidized bed with different viscous liquids and particles to study the hydrodynamics, average solid hold up and solid circulation rate. The effects of operating parameters, i.e., primary liquid flow rate in the riser, auxiliary liquid flow rate, total liquid flow rate and viscosity of the liq
Braz. J. Chem. Eng.. Publicado em: 2015-12
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7. Hydrodynamics and oxygen mass transfer characteristics of petroleum based micro-emulsions in a packed bed split-cylinder airlift reactor
The effects of aeration velocity and liquid properties on the pertinent hydrodynamic and mass transfer parameters in a split-cylinder airlift reactor (with and without packing) were examined. Four different oil-in-water micro-emulsion systems containing kerosene, heavy naphtha, light naphtha and diesel as the oil at the concentration of 7% (v/v) were used in
Braz. J. Chem. Eng.. Publicado em: 2013-09
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8. Avaliação fluidodinâmica do HDT em regime contracorrente com o uso da fluidodinâmica computacional - CFD / Computational fluid dynamics assessment of hydrotreating process in counter current operation
Processos comerciais de hidrotratamento (HDT) normalmente operam em regime de leito gotejante "Trickle bed" em concorrente com fluxos descendentes de gás e de líquido, sobre um leito de partículas de catalisador onde ocorrem as reações. É bem conhecido que a remoção de enxofre é fortemente inibida pelo efeito de adsorção competitiva de H2S nos sí
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/07/2012
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9. Investigation of hydrodynamics and transition regime in an internal loop airlift reactor using CFD
CFD modeling for an internal loop airlift reactor is developed for different superficial gas velocities, ranging from 0.015 to 0.073 m/s. Based on the presence of gas bubbles in the downcomer, three regimes can be generally classified as: no gas bubbles (I), stagnation of gas bubbles (II), and recirculation of gas bubbles into the riser (III). The aim of the
Braz. J. Chem. Eng.. Publicado em: 2012-12
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10. Parâmetros de dispersão de ar em células mecânicas de flotação em usinas brasileiras
O objetivo desse trabalho é apresentar e discutir a determinação dos parâmetros de dispersão de ar em células mecânicas de flotação, em circuitos industriais brasileiros. Foram investigados os circuitos rougher e scavenger das usinas RPM, Taquari-Vassouras, Copebras e Fosfértil-Catalão (atual Vale Fertilizantes). Nas usinas RPM e Taquari-Vassouras
Rem: Revista Escola de Minas. Publicado em: 2012-06
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11. Contractual solutions to the holdup problem: a survey
In this survey, we presented the general idea and main results from what we understand that are the most important contributions to contractual solutions to the holdup problem literature. The aim of this paper is to push the previous analysis, uniform the notation and provide a snapshot on the most recent literature, as well as bring topics for future inqui
Publicado em: 12/07/2011
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12. Flooding characteristics in pulsed packed extraction columns
Flooding behavior of a 76.2 mm diameter pulsed packed column has been determined using four different liquid-liquid systems. The effects of pulsation intensity, flow ratio, interfacial tension, and packing geometry on flood point have been investigated. The results showed that the maximum throughput of the column decreases with an increase in pulsation inten
Brazilian Journal of Chemical Engineering. Publicado em: 2011-12