Chemical Engineering Commons^™

Hydrodynamic Characteristics Of A Fluidized Bed With Rotating Distributor, C. Sobrino, S. Sánchez-Delgado, J. A. Almendros-Ibáñez, M. De Vega, U. Ruiz-Rivas, D. Santana

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

The performance of a novel rotating distributor fluidized bed is presented. The pressure drop and the standard deviation of pressure fluctuations, σp, were used to find the minimum fluidization velocity, Umf, and to characterize the quality of fluidization at different rotational speeds of the distributor plate. Experiments were conducted in the freely bubbling regime in a 0.19 m i.d. fluidized bed, operating with Group B particles according to Geldart’s classification. A decrease in Umf is observed when the rotational speed increases. Frequency analysis of pressure fluctuations shows that fluidization can be controlled by the adjustable rotational speed, at several excess …

Understanding The Hydrodynamics In A 2-Dimensional Downer By Cfd-Dem Simulation, Yongzhi Zhao, Yi Cheng, Yulong Ding, Yong Jin

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

The gas-solid flows in a 2-dimensional downer were simulated using a CFD-DEM method. The predicted macro-scale flow structure had good agreement with the experiments. The distinct clustering phenomena at meso-scale were revealed throughout the downer. Influences of the collision properties of the wall and the particles on the hydrodynamics in downer were investigated.

The Influence Of Distributor Design On Fluidized Bed Dryer Hydrodynamics, Michael Wormsbecker, Todd S. Pugsley, Helen Tanfara

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

The influence of perforated plate, punched plate and Dutch weave mesh distributor designs on fluidized bed dryer hydrodynamics was studied for a range of bed loadings and superficial gas velocities. The punched plate performs better than the other designs at a gas velocity of 1.5 m/s and bed loadings greater than 1.0 kg.

Four Approaches To Structure Gas-Solid Fluidized Beds, J. Ruud Van Ommen, John Nijenhuis, Marc-Olivier Coppens

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

Structuring fluidized beds can facilitate scale-up and increase conversion and selectivity by controlling the bubble size. We present four approaches to structure fluidized beds: oscillating the gas flow, distributing the gas injection, imposing an electric field to induce interparticle forces, and optimising distributed particle properties such as the size.

Tailoring Particle Mixtures For Fluidized Bed Reactors Using High-Throughput Experimentation, John Nijenhuis, J. Ruud Van Ommen

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

The goal of the described project is to design mixtures of particles with optimal fluidization properties. Using high-throughput experimentation, a novel approach for hydrodynamic research, the relevant properties can be obtained in a limited period of time. This approach is demonstrated by measuring the hydrodynamic characteristics of typical Geldart B powders.

Bubble Size And Mass Transfer In A Modified Airlift Loop Reactor With Continuous Slurry Phase, Mengxi Liu, Chunxi Lu, Mingxian Shi

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

A modified internal airlift loop reactor with continuous slurry phases was explored to investigate the local bubble size and the local mass transfer properties. A mathematical model was derived to simulate the bubble size in every flow region. Also, a new method was developed to measure the dissolved oxygen concentration.

Hydrodynamics Of Gas-Solids Bubbling Fluidized Beds Using Polyethylene Resin, Bangyou Wu, John Shepperson, Loni Van Der Lee, Céline Bellehumeur, Apostolos Kantzas

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

Pressure fluctuations were measured in three gas-solids bubbling fluidized beds (10cm, 20cm, and 30cm diameter, 1.0m high) using polyethylene particles of different sizes and particle size distributions. Both bed scale and particle size distribution significantly affect the gas-solids flow behavior. Bubble diameters measured from X-ray fluoroscopy in the 10cm diameter column were compared to various correlations in the literature.

Laser Diagnostics Of Hydrodynamics And Gas-Mixing In The Splash Zone Of Gas-Fluidized Beds, Roberto Solimene, Antonio Marzocchella, Raffaele Ragucci, Piero Salatino

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

The hydrodynamic patterns of gas flow associated with bubbles bursting at the surface of gas-fluidized beds have been investigated by means of planar laser induced fluorescence using acetone as diffusive gas tracer. The flow structures generated by the eruption of an isolated bubble have been characterized as a function of bed material size and of bubble injection level.

X-Ray Fluoroscopy Measurements And Cfd Simulation Of Hydrodynamics In A Two Dimensional Gas-Solids Fluidized Bed, Zhengxing He, Bangyou Wu, Blake Chandrasekaran, Celine Bellehumeur, Apostolos Kantzas

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

X-ray fluoroscopy measurements and CFD simulation were used to characterize the hydrodynamics in a pseudo 2-D gas-solids bubbling fluidized bed using polyethylene resin and glass beads. Bubble properties, such as bubble frequency, bubble size, bubble number distribution and bubble diameter distribution, were estimated from X-ray images and compared to those from CFD simulation.

Hydrodynamic Aspects And Correlations For The Design Of Draft-Tube Conical Spouted Beds, H. Altzibar, S. Alvarez, M.J. San José, R. Aguado, J. Bilbao, Martin Olazar

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

A study has been carried out on the hydrodynamics of conical spouted beds with draft tube. Correlations have been proposed for calculating minimum spouting velocity, operating pressure drop and peak pressure drop as functions of dimensionless module that take into account geometric factors, particle characteristics and operating conditions.

An Analysis Of Pressure Fluctuations In A Cfb Of Heavy Minerals, Adam Luckos, Quinn G. Reynolds , Paul Den Hoed

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

Pressure fluctuations were measured at high frequencies in a CFB model operated with air at ambient conditions. The model comprises an 80-mm-ID, 5-m-tall riser with a blind-T exit, a cyclone, a 50-mm-ID standpipe, and an L-valve. Tests were conducted with particles of natural rutile (TiO2), a heavy mineral mined from coastal dunes. The particles fall into group B of Geldart’s classification. The solids inventory was kept at 25 kg. The superficial gas velocity ranged from 3 to 6 m/s. The solid circulation flux varied between 10 and 40 kg/m2.s.

Profiles of solid concentrations in the riser are C-shaped. The amplitude …

Hydrodynamic Scale-Up Of Circulating Fluidized Beds, Ted Knowlton, S. B. Reddy Karri, J. S. Smith

The 12th International Conference on Fluidization - New Horizons in Fluidization Engineering

A general procedure that can be used to scale up circulating fluidized beds is presented. It consists of developing a mathematical model in conjunction with measuring 1) the radial dispersion coefficient (Dr) using gas tracers, 2) the radial solids velocity profile using a Pitot tube and 3) the radial distribution of solids density (1 - ε) using an optical probe. If the resulting information is obtained in a riser 200 mm or greater in diameter, it can be used in conjunction with the mathematical model for scale-up.