scholarly journals Effects of Rashig rings placed in interplate spaces and the rheological properties of the liquid phase on power consumption in a gassed reciprocating plate column

2003 ◽  
Vol 57 (3) ◽  
pp. 107-113
Author(s):  
Mirko Aleksic ◽  
Vlada Veljkovic ◽  
Ivana Bankovic-Ilic ◽  
Miodrag Lazic ◽  
Dejan Skala
Keyword(s):  
Liquid Phase ◽  
Power Consumption ◽  
Rheological Properties ◽  
Newtonian Liquid ◽  
Operating Conditions ◽  
Solid Particles ◽  
Distilled Water ◽  
Gas Velocity ◽  
Superficial Gas Velocity ◽  
Plate Column

The power consumption in a gassed reciprocating plate column with Rashig rings placed in interplate spaces increases with both increasing vibration intensity and content of solid particles but decreases with increasing the superficial gas velocity, regardless of the rheological properties of the liquid phase. Under the same operating conditions, the power consumption is higher when the column is filled with a non-newtonian liquid than with distilled water.

scholarly journals The influence of Rashig rings and the rheological properties of the liquid phase on the pressure drop at the bottom of a reciprocating plate column

2002 ◽  
Vol 56 (10) ◽  
pp. 409-414 ◽  
Author(s):  
Mirko Aleksic ◽  
Vlada Veljkovic ◽  
Ivana Bankovic-Ilic ◽  
Miodrag Lazic ◽  
Dejan Skala
Keyword(s):  
Liquid Phase ◽  
Pressure Drop ◽  
Rheological Properties ◽  
Solid Phase ◽  
Newtonian Liquid ◽  
Solid Particles ◽  
Distilled Water ◽  
Gas Velocity ◽  
Superficial Gas Velocity ◽  
Plate Column

The pressure drop at the column bottom, filled with a Newtonian (distilled water) or non-Newtonian (aqueous solution of carboxymethylcellulose, sodium salt, CMC, 1 %) liquid, in the presence of Rashig rings, made of aluminum (0.8 cm in diameter), regularly distributed in the interplate spaces (volume content of the solid phase: up to 3.2 %) was studied. The average and total pressure drop at the column bottom increased with increasing vibration speed and content of the solid particles, but decreased with increasing superficial gas velocity, indepentently of the rheological properties of the liquid phase. The pressure drop at the column bottom filled with the non-Newtonian liquid was found to be higher than that in the case of distilled water.

scholarly journals The gas holdup in a multiphase reciprocating plate column filled with carboxymethylcellulose solutions

2005 ◽  
Vol 70 (12) ◽  
pp. 1533-1544 ◽  
Author(s):  
Ivica Stamenkovic ◽  
Olivera Stamenkovic ◽  
Ivana Bankovic-Ilic ◽  
Miodrag Lazic ◽  
Vlada Veljkovic ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Power Consumption ◽  
Rheological Properties ◽  
Gas Holdup ◽  
Gas Velocity ◽  
Vibration Intensity ◽  
Three Phase ◽  
Solids Content ◽  
Superficial Gas Velocity ◽  
Plate Column

Gas holdup was investigated in a gas-liquid and gas-liquid-solid reciprocating plate column (RPC) under various operation conditions. Aqueous carboxymethyl cellulose (sodium salt, CMC) solutions were used as the liquid phase, the solid phase was spheres placed into interplate spaces, and the gas phase was air. The gas holdup in the RPC was influenced by: the vibration intensity, i.e., the power consumption, the superficial gas velocity, the solids content and the rheological properties of the liquid phase. The gas holdup increased with increasing vibration intensity and superficial gas velocity in both the two- and three-phase system. With increasing concentration of the CMC PP 50 solution (Newtonian fluid), the gas holdup decreased, because the coalescence of the bubbles was favored by the higher liquid viscosity. In the case of the CMC PP 200 solutions (non-Newtonian liquids), the gas holdup depends on the combined influence of the rheological properties of the liquid phase, the vibration intensity and the superficial gas velocity. The gas holdup in the three-phase systems was greater than that in the two-phase ones under the same operating conditions. Increasing the solids content has little influence on the gas holdup. The gas holdup was correlated with the power consumption (either the time-averaged or total power consumption) and the superficial gas velocity.

scholarly journals The effects of operating conditions on the pressure variation at the bottom of a 16.6 cm i.d. reciprocating plate column

2005 ◽  
Vol 11 (4) ◽  
pp. 195-202 ◽  
Author(s):  
Ljubisa Vasic ◽  
Ivana Bankovic-Ilic ◽  
Miodrag Lazic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Liquid Phase ◽  
Free Fraction ◽  
Pressure Variation ◽  
Operating Conditions ◽  
Solid Particles ◽  
Gas Velocity ◽  
Vibration Intensity ◽  
The One ◽  
Superficial Gas Velocity ◽  
Plate Column

The effects of the intensity of vibration, superficial gas velocity, content of solid particles and rheology of the liquid phase on the total and time-averaged pressure variation at the bottom of a 16.6 cm i.d. reciprocating plate column were studied. The total and time-averaged pressure variation at the column bottom were found to increase with increasing vibration intensity, liquid viscosity and content of solid particles, but to decrease with increasing superficial gas velocity. The pressure variation at the column bottom was greater in the column filled with CMC solutions than in the one with distilled water. The pressure variation at the column bottom was correlated with the vibration intensity and the liquid phase hold-up. The pressure variations at the bottom of columns of different diameter were also compared. The orifice coefficient for plates of approximately the same free fraction area was found to decrease with increasing column diameter.

scholarly journals Oxygen mass transfer in a 16.6 cm i.d. multiphase reciprocating plate column

2007 ◽  
Vol 72 (5) ◽  
pp. 523-531 ◽  
Author(s):  
Ljubisa Vasic ◽  
Ivana Bankovic-Ilic ◽  
Miodrag Lazic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Solid Particles ◽  
Oxygen Mass Transfer ◽  
Column Diameter ◽  
Specific Time ◽  
Gas Velocity ◽  
Vibration Intensity ◽  
Superficial Gas Velocity ◽  
Plate Column

The effects of vibration intensity, superficial gas velocity and content of solid particles on the volumetric oxygen mass transfer coefficient (k 1 a) in a 16.6 cm i.d. multiphase reciprocating plate column were studied. The k 1 a increased with increasing vibration intensity and superficial gas velocity, and decreased with increasing content of solid particles. The k 1 a was correlated with the specific time-averaged power consumtion, the superficial gas velocity, the column diameter and the content of solid particles.

scholarly journals Effect of Solid Particles on the Gas Hold Up in the Fluidized Bed Columns: Experimental and Mathematical Studies

2021 ◽  
Vol 12 (4) ◽  
pp. 5004-5011
Keyword(s):  
Particle Density ◽  
Tap Water ◽  
Particle Diameter ◽  
Gas Holdup ◽  
Operating Conditions ◽  
Solid Particles ◽  
Bubble Columns ◽  
Solid Concentration ◽  
Gas Velocity ◽  
Superficial Gas Velocity

The present research investigated the effect of solid properties on the gas holdup of the fluidization bed bubble columns (FBCS). All experiments were performed in the constant clear tap water of 80 cm height. The range of solid particle diameters was 0.7 – 2 mm with two different densities of 1075 and 1200 kg/m3, superficial air velocities 4 – 7 cm/s. It was observed that there are proportional relationships between superficial gas velocity and particle diameter with the gas holdup. While an inverse relationship between solid concentration and particle density with the gas holdup. Mathematical and statistical analysis was also used as a powerful way to represent the gas hold up as a function of different operating conditions.

scholarly journals Gas-holdup in a 16.6 cm I.D. reciprocating plate column

2005 ◽  
Vol 59 (9-10) ◽  
pp. 263-266
Author(s):  
Ljubisa Vasic ◽  
Ivana Bankovic-Ilic ◽  
Miodrag Lazic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Power Consumption ◽  
Gas Flow ◽  
Gas Holdup ◽  
Specific Power ◽  
Specific Power Consumption ◽  
Gas Velocity ◽  
Two Phase ◽  
Operation Conditions ◽  
Superficial Gas Velocity ◽  
Plate Column

The effects of operation conditions (the vibration intensity and gas flow rate) on the gas holdup in a 16.6 cm i.d. two-phase reciprocating plate column (RPC) were studied. Distilled water and aqueous solutions of carboxymethyl-cellulose of different concentration were used as the liquid phase and air as the gas phase in this investigation. The gas holdup was measured after the gas flow and the reciprocating action had been stopped. An empirical correlation which correlates the gas holdup with the specific power consumption and the superficial gas velocity showed that the aeration intensity had a greater influence on the gas holdup than the intensity of agitation. Because the gas holdup was approximately the same in RPC's of different diameters, an equation relating the gas holdup with the specific power consumption and the superficial gas velocity was derived. The correlation could be used in the scaling up of reciprocating plate columns.

scholarly journals Effect of Surfactants on Gas Holdup in Shear-Thinning Fluids

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Shaobai Li ◽  
Siyuan Huang ◽  
Jungeng Fan
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Sodium Dodecyl ◽  
Shear Thinning ◽  
Gas Holdup ◽  
Bubble Columns ◽  
Gas Velocity ◽  
Shear Thinning Fluids ◽  
Liquid Surface Tension ◽  
Superficial Gas Velocity

In this study, the gas holdup of bubble swarms in shear-thinning fluids was experimentally studied at superficial gas velocities ranging from 0.001 to 0.02 m·s−1. Carboxylmethyl cellulose (CMC) solutions of 0.2 wt%, 0.6 wt%, and 1.0 wt% with sodium dodecyl sulfate (SDS) as the surfactant were used as the power-law (liquid phase), and nitrogen was used as the gas phase. Effects of SDS concentration, rheological behavior, and physical properties of the liquid phase and superficial gas velocity on gas holdup were investigated. Results indicated that gas holdup increases with increasing superficial gas velocity and decreasing CMC concentration. Moreover, the addition of SDS in CMC solutions increased gas holdup, and the degree increased with the surfactant concentration. An empirical correlation was proposed for evaluating gas holdup as a function of liquid surface tension, density, effective viscosity, rheological property, superficial gas velocity, and geometric characteristics of bubble columns using the experimental data obtained for the different superficial gas velocities and CMC solution concentrations with different surfactant solutions. These proposed correlations reasonably fitted the experimental data obtained for gas holdup in this system.

scholarly journals Gas hold-up in a three-phase reciprocating plate column

2005 ◽  
Vol 70 (11) ◽  
pp. 1363-1371 ◽  
Author(s):  
Ljubisa Nikolic ◽  
Vesna Nikolic ◽  
Vlada Veljkovic ◽  
Dejan Skala
Keyword(s):  
Solid Phase ◽  
Liquid System ◽  
Column Diameter ◽  
Gas Velocity ◽  
Vibration Intensity ◽  
Three Phase ◽  
Superficial Gas Velocity ◽  
Phase Column ◽  
Plate Column ◽  
Good Agreement

The influence of the geometry of a reciprocating plate column (diameter), superficial gas velocity, vibration intensity and content of the solid phase in the column on the gas hold-up in a three phase column (G-L-S) were investigated in this study. For comparison, the gas hold-up was also analyzed in a gas-liquid system (G-L) in the same type of column. Good agreement between the experimentally determined values of the gas hold-up and those calculated on the basis of the derived correlation for the G-L and G-L-S system was obtained.

Bubble Diameter and Effective Interfacial Area in a Novel Hybrid Rotating and Reciprocating Perforated Plate Bubble Column

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Dhanasekaran S ◽  
Karunanithi T
Keyword(s):  
Liquid Velocity ◽  
Bubble Column ◽  
Bubble Diameter ◽  
Perforated Plate ◽  
Interfacial Area ◽  
Gas Velocity ◽  
The Mean ◽  
Superficial Gas Velocity ◽  
Plate Column

This investigation reports on the experimental and theoretical investigation carried out to evaluate the bubble diameter and effective interfacial area in a novel Hybrid Rotating and Reciprocating Perforated Plate Bubble Column. Air-water system is used in this investigation. Countercurrent mode is employed. The effects of agitation level, superficial gas velocity and superficial liquid velocity on the bubble size distribution are studied. The mean bubble diameter is predicted using photographic technique. A simple correlation is developed for the determination of mean bubble diameter. It is found that the mean bubble diameter values for hybrid column are 1.8 to 2.5 times smaller when compared with conventional reciprocating plate column. The interfacial area is calculated based on the experimental results of the gas holdup and bubble diameter. Effects of agitation level, superficial gas velocity, superficial liquid velocity and plate free area on the interfacial area have been investigated. Correlations are developed for the determination of interfacial area for both mixer-settler and emulsion regions. It could be noted that the interfacial area for the hybrid column is 3 to 6 times higher in both mixer-settler region and emulsion region than that of conventional reciprocating plate column which is quite large.

Solids-Loading Measurements in a Gas-Solid Riser

Volume 1 ◽  
2004 ◽  
Author(s):  
T. J. O’Hern ◽  
S. M. Trujillo ◽  
J. B. Oelfke ◽  
P. R. Tortora ◽  
S. L. Ceccio
Keyword(s):  
Catalytic Cracking ◽  
Volume Fraction ◽  
Electrode System ◽  
Operating Conditions ◽  
Fluid Catalytic Cracking ◽  
Gas Velocity ◽  
Cross Sectional ◽  
Solids Loading ◽  
Special Cases ◽  
Superficial Gas Velocity

Gas-solid multiphase flows are commonly used in chemical processing, petroleum fluid catalytic cracking, and other industrial applications. The distribution of the solid phase in gas-solid flows (generally in the form of small particles) is seldom uniform, but more commonly involves clusters, streamers, and core-annular distributions, depending on the flow orientation and the overall gas and solid flowrates and their ratio. For this reason, tomographic techniques are of great interest for measurement of cross-sectional solids distributions in such flows. The cross-sectional profiles of solids loading can be integrated to yield a cross-sectionally averaged solids loading. Determination of this averaged solids loading is needed to understand the axial variations of solids loading and its sensitivity to flow parameters and to optimize performance. A common technique for determining volume-averaged solids loading in vertical flows like the riser section of a circulating fluidized bed (CFB) is by measurement of the time-averaged axial pressure gradients along the riser axis (differential pressure or ΔP method). Neglecting acceleration and wall friction, the axial momentum balance simplifies to equate the multiphase hydrostatic pressure term with the pressure gradient along the axis. Many authors (e.g., Louge and Chang, 1990) have pointed out the neglected terms in this approach and generally show that ΔP is applicable in the special cases of no solids-loading gradient (fully developed flow) or small solids flux. A more generally applicable technique for measuring solids loading in gas-solid flows is gamma tomography. A gamma tomography system using a 100-mCi Cs-137 source collimated into a fan beam and an array of scintillation detectors, has been developed and implemented for application to a cold-flow (non-reacting) CFB. The CFB has a 14-cm-ID 6-m tall riser, and is currently operated with a multiphase mixture of air and fluid catalytic cracking (FCC) catalyst particles. Typical operating conditions include mean superficial gas velocities up to 7.4 m/s and solids fluxes up to approximately 100 kg/m2·s. Quantitative comparison of gamma- and ΔP-determined solids loadings was made over a range of operating conditions (combination of superficial gas velocity and solids flux). Results indicate that the differences between gamma and ΔP-determined cross-sectionally averaged solids loading are most pronounced near the base of the riser, where solids concentration is highest and the mixture is accelerating. Higher in the riser, the agreement is better. Additionally, the difference is larger in cases of higher superficial gas velocity. In addition, several studies were performed to design an electrical-impedance tomography (EIT) system for a gas-solid flow to collect data suitable for validating computational models. A two-electrode bulk impedance system was studied experimentally. The required accuracy, spatial resolution and temporal resolution of an EIT system are addressed, and modeling and reconstruction are discussed. Bulk solid volume fractions measured by the two-electrode system and by gamma-densitometry tomography are in general agreement. Experiments with the two-electrode system also show that the Maxwell-Hewitt relation, used to convert the mixture impedance to solid volume fraction, must be applied carefully, paying attention to the identity of the dispersed and continuous phases. The design of a 16-electrode system is also described.

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