scholarly journals Experimental Study on Pressure Drop and Flow Dispersion in Packed Bed of Natural Zeolite

2018 ◽  
Vol 156 ◽  
pp. 02006
Author(s):  
Petric Marc Ruya ◽  
Herri Susanto ◽  
Mubiar Purwasasmita
Keyword(s):  
Pressure Drop ◽  
Natural Zeolite ◽  
Air Flow ◽  
Plug Flow ◽  
Particle Diameter ◽  
Packed Bed ◽  
Transitional Flow ◽  
Ergun Equation ◽  
Hydrodynamic Behaviour ◽  
Bed Height

The use of conventional correlation for pressure drop and dispersion coefficient calculation may result in inaccurate values for zeolite packed bed as the correlations are generally developed for regularly shaped and uniformly sized particles. To support the research on the application of modified natural zeolite as tar cracking catalyst, the research on the hydrodynamic behaviour of zeolite packed bed has been conducted. Experiments were carried out using a glass column with diameter of 37.8 mm. Natural zeolite with particle size of about 2.91 to 6.4 mm was applied as packing material in the column, and the bed height was varied at 9, 19 and 29 cm. Air was used as the fluid that flows through the bed and nitrogen was used as a tracer for residence time distribution determination. Air flow rates were in the range of 20 to 100 mL/s which correspond to the laminar-transitional flow regime. The pressure drops through the bed were in the range of 1.7 to 95.6 Pa, depending on the air flow rate and bed height. From these values, the parameters in the Ergun equation were estimated, taking into account the contribution by wall effect when the ratio of column to particle diameter is low. The viscous and inertial term constants in the Ergun equation calculated ranges from 179 to 199 and 1.41 to 1.47 respectively while the particle sphericity ranges from 0.56 to 0.59. The reactor Peclet number were determined to range from 5.2 to 5.5, which indicated significant deviation from a plug flow condition.

Plug Flow of Coarse Particles in a Horizontal Pipe

1982 ◽  
Vol 104 (2) ◽  
pp. 198-206 ◽  
Author(s):  
Y. Tsuji ◽  
Y. Morikawa
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Air Flow ◽  
Plug Flow ◽  
Packed Bed ◽  
Coarse Particles ◽  
Air Flow Rate ◽  
Horizontal Pipe ◽  
Main Pipe ◽  
Secondary Air

Plug flow of coarse particles was investigated experimentally in a horizontal pipe, in which a sub-pipe for secondary air injection was installed. Measurements were made about the plug motion, pressure drop, and transportation properties, and the roles of the main and sub-pipe air flow were clarified. The main air flow increases the number of plugs, while the sub-pipe air flow increases the plug velocity. The higher the main pipe air flow rate, the more regular the motion. The height of a stationary layer of deposited particles, which is built on the bottom of the main pipe, decreases with increasing the sub-pipe air flow rate. The pressure drop in the moving plug is quantitatively much smaller than that in the stationary packed bed of same particles.

The Pressure Drop at Critical Fluidization of Large Particles in Vibrated Fluidization Bed

2012 ◽  
Vol 550-553 ◽  
pp. 2763-2766
Author(s):  
Xue Jun Zhu ◽  
Jun Deng
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Large Particle ◽  
Particle Diameter ◽  
Future Design ◽  
Vibration Strength ◽  
Bed Height ◽  
Large Particles ◽  
Vibrated Fluidized Bed ◽  
Critical Fluidization

The pressure drop at critical fluidization for two-dimensional vibrated fluidized bed(240 mm×80 mm) was studied, with large particle glass beads of average diameters dp of 1.8mm, 2.5mm and 3.2mm.The effect of the vibration strength, the static bed height and the particle diameter on the pressure drop was analyzed. The results of the study show that the pressure drop decreases with the increase of the vibration strength. It plays an even more prominent part with decreases of the static bed height and the particle diameter. The empirical correlation equations to predict the pressure drop was established, and the results of the prediction was compared with the experimental data, the error is in range of ±10%. The results can provide references for future design and research on the vibrated fluidized bed.

scholarly journals WALL EFFECT OF A PACKED BED WITH PELLET PARTICLES

2018 ◽  
Vol 56 (2A) ◽  
pp. 31-36
Author(s):  
Tran Duy Hai
Keyword(s):  
Flow Rate ◽  
Particle Diameter ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Radial Coordinate ◽  
Flow Profile ◽  
Local Velocity ◽  
Gas Velocity ◽  
Bed Height ◽  
Small Ratio

Fluid flow profile is a dominate role in the performance of packed bed reactor. In small ratio of column-to-particle diameter, velocity pattern is strongly affected by voidage distribution, which depends on radial coordinate, flow rate and bed height. In this study, effects of voidage distribution to gas velocity profile in a packed bed with pellet particles was empirically investigated. Uniformity of local velocity at the top of the bed was clearly observed with decreasing of bed height and flow rate. For 400 mm of bed height, the measured velocities are a well fitting to Fahien and Stankovich model for any expected flow rate.

A Study on Fluidized Bed-Type Particulate Filter for Diesel Engines

2007 ◽  
Vol 129 (4) ◽  
pp. 1072-1078 ◽  
Author(s):  
Sung-Sub Kee ◽  
Ali Mohammadi ◽  
Takuji Ishiyama ◽  
Takaaki Kakuta
Keyword(s):  
Particle Size ◽  
Diesel Engine ◽  
Pressure Drop ◽  
Fluidized Bed ◽  
Particle Diameter ◽  
Filtration Efficiency ◽  
Particulate Filter ◽  
Design Parameters ◽  
Gas Velocity ◽  
Bed Height

A fluidized bed-type diesel particulate filter (DPF) was applied to filter particulate matter (PM) in diesel engine exhaust gas. The effects of the fluidized bed design parameters, such as gas velocity, bed particle size, and height, on PM and smoke filtration efficiencies, and pressure drop were experimentally investigated using a single-cylinder direct injection (DI) diesel engine. High PM filtration efficiency and low pressure drop were achieved with the DPF, especially at a lower gas velocity. The PM filtration efficiency was higher with a smaller bed particle size at the lower gas velocity; however, it drastically decreased with an increase in gas velocity due to excessive fluidization of the bed particles. Increase in bed height led to higher PM filtration efficiency while causing an increase in pressure drop. The theoretical work was also conducted for further investigation of the effects of the above-mentioned parameters on PM filtration. These results indicated that diffusion filtration was the dominant mechanism for PM filtration under the conditions of this study and that the decrease in PM filtration efficiency at high gas velocity was caused by a deterioration in the diffusion filtration. The bed particle diameter and the bed height should be optimized in order to obtain a high filtration efficiency without increasing the DPF size.

scholarly journals Numerical Simulation of Flow and Heat Transfer in Structured Packed Beds with Smooth or Dimpled Spheres at Low Channel to Particle Diameter Ratio

Energies ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 937 ◽  
Author(s):  
Shiyang Li ◽  
Lang Zhou ◽  
Jian Yang ◽  
Qiuwang Wang
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Heat Transfer Performance ◽  
Particle Diameter ◽  
Packed Bed ◽  
Packed Beds ◽  
Transfer Performance ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer

Packed beds are widely used in catalytic reactors or nuclear reactors. Reducing the pressure drop and improving the heat transfer performance of a packed bed is a common research aim. The dimpled structure has a complex influence on the flow and heat transfer characteristics. In the present study, the flow and heat transfer characteristics in structured packed beds with smooth or dimpled spheres are numerically investigated, where two different low channel to particle diameter ratios (N = 1.00 and N = 1.15) are considered. The pressure drop and the Nusselt number are obtained. The results show that, for N = 1.00, compared with the structured packed bed with smooth spheres, the structured packed bed with dimpled spheres has a lower pressure drop and little higher Nusselt number at 1500 < ReH < 14,000, exhibiting an improved overall heat transfer performance. However, for N = 1.15, the structured packed bed with dimpled spheres shows a much higher pressure drop, which dominantly affects the overall heat transfer performance, causing it to be weaker. Comparing the different channel to particle diameter ratios, we find that different configurations can result in: (i) completely different drag reduction effect; and (ii) relatively less influence on heat transfer enhancement.

scholarly journals Hydrodynamic characteristics of a two-phase gas-liquid flow upward through a fixed bed of spherical particles

2001 ◽  
Vol 66 (1) ◽  
pp. 53-64 ◽  
Author(s):  
Snezana Serbula ◽  
Velizar Stankovic
Keyword(s):  
Pressure Drop ◽  
Liquid Velocity ◽  
Fixed Bed ◽  
Particle Diameter ◽  
Packed Bed ◽  
Spherical Particles ◽  
Hydrodynamic Characteristics ◽  
Phase System ◽  
Relative Pressure ◽  
Two Phase

The influence of an electrochemically generated gas phase on the hydrodynamic characteristics of a three-phase system has been examined. The two-phase fluid, (gas-liquid), in which the liquid phase is the continuous one, flows through a packed bed with glass spheres. The influence of the liquid velocity was examined, as well as the gas velocity and particle diameter on the pressure drop through the fixed bed. It was found that with increasing liquid velocity (wl = 0.0162-0.03 m/s), the relative pressure drop decreases through the fixed bed. With increasing current density, the pressure drop increases, since greater gas quantities stay behind in the fixed bed. Besides, it was found that with decreasing diameter of the glass particles, the relative pressure drop also decreases. The relationship betweeen the experimentally obtained friction factor and the Reynolds number was established.

Prediction of Pressure Drop in Air-Water Two Phase Upflow Through Packed Bed

2010 ◽  
Author(s):  
Nan Zhang ◽  
Zhongning Sun
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Flow Model ◽  
Homogeneous Model ◽  
Great Influence ◽  
Particle Diameter ◽  
Predictive Ability ◽  
Packed Bed ◽  
Two Phase ◽  
Model Based

The resistance characteristics of air-water flow upward through packed bed have been studied experimentally. Experiments were conducted in transparent tube with 50mm inner diameter filled with glass spheres of which the diameters are 2, 5 and 8mm, respectively. Experimental results show that the pressure drop increases with the increasing of gas-liquid mass flow rate, and has a certain relationship with the flow pattern. The different particle diameter and porosity have great influence on pressure drop under the same flow condition. The applicability of several representative correlations for calculating the two-phase pressure drop and two new correlations were evaluated against 234 group experimental data. All compared correlations can be grouped into two, namely: (a) the separated flow model based on Lockhart & Matinelli method (b) the homogeneous model based on gas and liquid Reynolds number. The results show that: (1) the best agreement between measured and calculated values is obtained with the correlations based on separate flow model, but the predictive ability is reduced with the increasing of particle diameter. (2) the existing homogeneous model shows the considerable discrepancies with experiment values; however the modified homogeneous correlation by considering particle-to-column diameter ratio and porosity gives good agreement with experimental data.

Determination of pressure drop for air flow through sintered metal porous media using a modified Ergun equation

2016 ◽  
Vol 27 (4) ◽  
pp. 1134-1140 ◽  
Author(s):  
Wei Zhong ◽  
Ke Xu ◽  
Xin Li ◽  
Yuxuan Liao ◽  
Guoliang Tao ◽  
...  
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Air Flow ◽  
Ergun Equation ◽  
Sintered Metal ◽  
Flow Through

scholarly journals An Experimental Study of Gas Flow Regime and Pressure Drop in a Random Packed Bed with Sinter Particles

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 872
Author(s):  
Zude Cheng ◽  
Haitao Wang ◽  
Junsheng Feng ◽  
Hui Dong
Keyword(s):  
Pressure Drop ◽  
Turbulent Flow ◽  
Flow Regime ◽  
Gas Flow ◽  
Particle Diameter ◽  
Flow Regimes ◽  
Packed Bed ◽  
Superficial Velocity ◽  
Experimental Conditions ◽  
Gas Flow Regime

The gas flow regime and pressure drop in a gas–solid packed bed with irregularly shaped sinter particles were experimentally investigated. Using a self-made experimental facility for data measurement, the gas flow pressure drop in a sinter bed layer was determined for various experimental conditions. According to the changes in the modified coefficients, α and β, for different flow regimes, the flow transitions from one regime to another in packed beds with different particle diameters were described. Furthermore, the pressure drop correlations for different flow regimes were determined, and the reliabilities of the obtained correlations were contrastively analyzed. The results show that, when the particle diameter is constant, the modified pressure drop per unit height, ΔP/Hu, increases linearly with the increasing gas superficial velocity. When the gas superficial velocity is larger than 1.15 m/s under atmospheric conditions, the gas flow regime in the sinter bed layer is the turbulent flow. Compared with the experimental correlation of the whole flow, the pressure drop correlations obtained by the piecewise fitting method provided a better prediction of the experimental values, and the average deviations of the obtained correlations for the Forchheimer flow and the turbulent flow were 5.31% and 4.07%, respectively.

COMBUSTION BEHAVIOR OF LUMPY COKE IN PACKED BED IN A COUNTER CURRENT AIR FLOW

2018 ◽  
Author(s):  
Bassem Hallak ◽  
N. Linn ◽  
Eckehard Specht ◽  
Fabian Herz
Keyword(s):  
Air Flow ◽  
Packed Bed ◽  
Combustion Behavior ◽  
Counter Current
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