The Influence of the Distributor Plate on the Bottom Zone of a Fluidized Bed Approaching the Transition from Bubbling to Turbulent Fluidization

Paiva, João Monney; Pinho, Carlos; Figueiredo, A.R.

doi:10.1205/026387604772803043

Cited by 18 publications

(10 citation statements)

References 11 publications

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“…The velocity value at which it occurs seems to be consistent with the onset transition values from bubbling to turbulent regimes (Chen and Bi, 2003;Paiva et al, 2004). However, this subject requires further considerations and extends beyond the scope of the present study.…”

Section: Effect Of Superficial Velocity On Fluidization Qualitysupporting

confidence: 71%

Influence of the Distributor Plate and Operating Conditions on the Fluidization Quality of a Gas Fluidized Bed

Paiva

Pinho

Figueiredo

2008

Chemical Engineering Communications

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Experiments were carried out to examine the influence of both the type and the pressure drop of distributor plates on the fluidization quality of an atmospheric fluidized bed. Three different distributor types were used, perforated Perspex, metallic mesh, and porous ceramic, with pressure drops ranging from 0.05 to 350 kPa and superficial air velocities ranging from 0.1 to 2.3 m=s. Three sizes of silica Ballotini beads, 355-425, 600-710, and 850-1000 mm, were used as bed material. The static bed height was set to 300 mm and was divided into six horizontal 50 mm high slices. For each slice, pressure drop values were recorded for U 0 =U mf ratios from 20 to 1. In order to produce a reference for the pressure drop evolution, a modification of the two-phase theory was introduced, taking into consideration the increase in the average global porosity as well as the change in the ratio of flow through the bubbles versus the flow through the dense phase. This allowed assessment of the influence of the different operating conditions and setups on the quality of fluidization, Q Ã .

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Section: Effect Of Superficial Velocity On Fluidization Qualitysupporting

confidence: 71%

Influence of the Distributor Plate and Operating Conditions on the Fluidization Quality of a Gas Fluidized Bed

Paiva

Pinho

Figueiredo

2008

Chemical Engineering Communications

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“…Some studies were conducted on the particles size of the fluidization catalyst [8][9][10]. Hatzantonis et.…”

Section: Introductionmentioning

confidence: 99%

“…al. [8] studied the influence of the distributor on the bottom zone of the fluidized bed approaching the transition from bubbling to fluidization. Results showed that the flow changes with the change in operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Oxychlorination Process Optimization for the Conversion of Ethylene to Ethylene Dichloride

El-Maghraby,

Youssef,

Shoaib

2020

IJRTE

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The catalytic oxychlorination of ethylene is widely used for the production of ethylene dichloride (EDC) which is an essential step for the production of poly-vinyl chloride (PVC). However, catalyst entrainment from the fluidization reactor has formed a problem and caused the loss of expensive catalyst powder with the outlet gas, hence less conversion in achieved. In this research we studied the catalytic oxychlorination of ethylene over the surface of geldart A powder with average particle size of 80 microns. Simulation was developed using Aspen plus and Mat Lab. It was validated against the industrial data and they were matching. Various operating conditions and variables were studied. The effect of fluidized gas velocity, bubble diameter, temperature and pressure on solid catalyst entrainment rate. In addition, the copper content from the quencher bottom was analyzed. It was found that the entrainment rate increased with the increase in fluidized gas velocity, bubble diameter, reactor temperature and pressure. While on the other hand increasing orifice diameter decreased the amount of entrained catalyst within the fluidized bed.It was found that the optimum superficial gas velocity is 2570.4 m 3 /hr.and the optimum orifice diameter is 1 cm. At this condition the lowest rate of solids entrainment out of the bed will be reached. This will decrease the amount of lost catalyst and the process will be more economic with higher gas conversion.

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“…A gas distributor is usually used in fluidized bed operations. There are different types of gas distributors including porous plates, perforated plates and tuyere nozzles (Paiva et al, 2004;Kunii and Levenspiel, 1991). A gas distributor helps to ensure uniform gas distribution to achieve a stable operation.…”

Section: Introductionmentioning

confidence: 99%

Distribution of Solids in a Fluidized Bed Operated without a Gas Distributor

Agu¹,

Moldestad²

2018

Linköping Electronic Conference Proceedings

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Despite several advantages of a gas distributor, there are also some challenges in its application. Using a gas distributor increases the fluidizing gas compression cost. Due to deposition of fine particles and product of chemical corrosion, the gas flow area across a distributor may also be reduced. This paper investigates the distribution of solids in a fluidized bed operated without a gas distributor. The gas supply is through two opposite points on the column wall. In this bed configuration, the fluidized bed behaviour simulated using the CPFD (Computational Particle-Fluid dynamics) Barracuda code is compared with an equivalent system where a uniform gas distribution is assumed. For different powders with mean size 480-710 µm, the results show that the axial distribution of pressure fluctuation in both types of bed configurations are similar, particularly near the bottom of the bed. The relative solid fraction fluctuation is lower than 0.2 around the central axis and it spans over 21-83% and 41-65% of the bed diameter, respectively. These results therefore show that stable bubbling behaviour and good distribution of solids can also be achieved in a bed operated without any distributor.

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The Influence of the Distributor Plate on the Bottom Zone of a Fluidized Bed Approaching the Transition from Bubbling to Turbulent Fluidization

Cited by 18 publications

References 11 publications

Influence of the Distributor Plate and Operating Conditions on the Fluidization Quality of a Gas Fluidized Bed

Influence of the Distributor Plate and Operating Conditions on the Fluidization Quality of a Gas Fluidized Bed

Catalytic Oxychlorination Process Optimization for the Conversion of Ethylene to Ethylene Dichloride

Distribution of Solids in a Fluidized Bed Operated without a Gas Distributor

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