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Two-phase Pressure Drop (two-phase + pressure_drop)

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Chemistry100%

Selected Abstracts

Prediction of two-phase pressure drop and liquid holdup in co-current gas,liquid downflow of air,Newtonian systems through packed beds

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2006
Ponnan Ettiyappan Jagadeesh Babu
Abstract The dependency of pressure drop and liquid holdup on phase velocities, geometry of the column and packing materials as well as on the physical properties have been analyzed. Our experimental data (825 data points obtained using four liquid systems and three different particles) along with those of the available literature (776 data point from five different sources) were used for the analysis. The applicability and the limitations of the literature correlations were evaluated using the available data. Based on the analysis, new correlations for the estimation of pressure drop and liquid holdup, valid for low and high interaction regimes have been developed using the available data, with a wide range of variables. Copyright © 2005 Society of Chemical Industry [source]

Volume-of-fluid-based model for multiphase flow in high-pressure trickle-bed reactor: Optimization of numerical parameters

AICHE JOURNAL, Issue 11 2009
Rodrigo J. G. Lopes
Abstract Aiming to understand the effect of various parameters such as liquid velocity, surface tension, and wetting phenomena, a Volume-of-Fluid (VOF) model was developed to simulate the multiphase flow in high-pressure trickle-bed reactor (TBR). As the accuracy of the simulation is largely dependent on mesh density, different mesh sizes were compared for the hydrodynamic validation of the multiphase flow model. Several model solution parameters comprising different time steps, convergence criteria and discretization schemes were examined to establish model parametric independency results. High-order differencing schemes were found to agree better with the experimental data from the literature given that its formulation includes inherently the minimization of artificial numerical dissipation. The optimum values for the numerical solution parameters were then used to evaluate the hydrodynamic predictions at high-pressure demonstrating the significant influence of the gas flow rate mainly on liquid holdup rather than on two-phase pressure drop and exhibiting hysteresis in both hydrodynamic parameters. Afterwards, the VOF model was applied to evaluate successive radial planes of liquid volume fraction at different packed bed cross-sections. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Pressure buildup in gas-liquid flow through packed beds due to deposition of fine particles

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2002
Murray R. Gray
Abstract In order to understand the increase in pressure drop in hydrotreating reactors due to deposition of fine solids, experiments were conducted with a model suspension of kaolin clay in kerosene. The suspension was circulated through packed beds of catalyst pellets in the trickle-flow and pulse-flow regimes, and the increase in pressure drop measured as a function of particle concentration in the bed. The increase in pressure drop was linear with particle concentrations over the range 0,60 kg.m,3. A consistent approach to modeling the pressure drop behavior was to determine an effective porosity of the packed bed as a function of the concentration of fine particles, then use this porosity in the Ergun equation as a basis for calculating the two-phase pressure drop. Afin de comprendre l'augmentation de perte de charge causée par le dépôt de solides fins dans les réacteurs d'hydrotraitement, des expériences ont été menées avec une suspension modèle d'argile de kaolin dans du kérosène. On a fait circuler la suspension dans des lits garnis de pastilles de catalyseur en régime à écoulement ruisselant et à écoulement pulsé et on a mesuré l'augmentation de perte de charge en fonction de la concentration de particules dans le lit. L'augmentation de la perte de charge est linéaire pour des concentrations de particules se situant dans la gamme de 0,60 kg.m,3. Une façon cohérente de modéliser le comportement de la perte de charge consiste à déterminer une porosité effective du lit garni en fonction de la concentration de fines, puis d'utiliser cette porosité dans l'équation d'Ergun comme base pour calculer la perte de charge diphasique. [source]

Oil,water two-phase flow in microchannels: Flow patterns and pressure drop measurements

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 6 2008
Abdelkader Salim
Abstract This paper investigates oil,water two-phase flows in microchannels of 793 and 667 µm hydraulic diameters made of quartz and glass, respectively. By injecting one fluid at a constant flow rate and the second at variable flow rate, different flow patterns were identified and mapped and the corresponding two-phase pressure drops were measured. Measurements of the pressure drops were interpreted using the homogeneous and Lockhart,Martinelli models developed for two-phase flows in pipes. The results show similarity to both liquid,liquid flow in pipes and to gas,liquid flow in microchannels. We find a strong dependence of pressure drop on flow rates, microchannel material, and the first fluid injected into the microchannel. On étudie dans cet article les écoulements diphasiques huile-eau dans des micro-canaux de 793 µm et 667 µm de diamètre hydraulique faits de quartz et de verre, respectivement. En injectant un fluide à un débit constant et le second à un débit variable, différents schémas d'écoulements ont été observés et représentés en diagrammes, et les pertes de charge diphasiques correspondantes ont été mesurées. Les mesures de perte de charge ont été interprétées à l'aide du modèle homogène et du modèle de Lockhart,Martinelli mis au point pour les écoulements diphasiques dans les conduites. Les résultats montrent une similarité à la fois avec l'écoulement liquide-liquide et l'écoulement liquide de gaz dans des micro-canaux. On a trouvé une forte dépendance de la perte de charge aux débits, au matériau des micro-canaux et au premier fluide injecté dans le micro-canal. [source]