scholarly journals Analysis of the Hydrodynamic Effects of Gas Permeation in a Pilot-Scale Fluidized Bed Membrane Reactor

2018 ◽  
Vol 9 (1) ◽  
pp. 67
Author(s):  
Chenxi Bai ◽  
Yao Xiao ◽  
Ruifeng Peng ◽  
John Grace ◽  
Yumin Chen
Keyword(s):  
Fluidized Bed ◽  
Bubble Size ◽  
Membrane Reactor ◽  
Scale Up ◽  
Pilot Scale ◽  
Gas Permeation ◽  
Gas Extraction ◽  
Gas Velocity ◽  
Attenuation Rate ◽  
Hydrodynamic Effects

This study experimentally investigates the effects of gas extraction/addition, via multiple vertical membrane panels, on the hydrodynamics in different regions of a pilot-scale gas fluidized bed membrane reactor (FBMR), based on differential pressure signals measured at different vertical bed sections at high temperature. In a bed section where membrane panels were installed and activated, the extraction of gas caused the average bubble size to increase, but decreased the number of small- and medium-sized bubbles. This effect of gas extraction penetrated into bed sections above the active membrane panel, but attenuated with increasing distance away from the extraction location. The attenuation rate was much faster in FBMR with lower bed voidage, mainly due to the large decrease of the drag force exerted by gas extraction on fluidizing gas in a denser bed. With the same inlet gas velocity, gas addition favored the growth of bubbles, especially in the upper bed sections compared with operation without gas permeation. The increase of the effective fluidizing velocity was the major reason for the increase of the bubble size during gas addition. These findings preliminarily suggest that membrane units should not be installed in or below fast-reacting zones in a scale-up FBMR, and operation with a lower bed voidage is preferable to avoid the formation of large bubbles enhanced by gas extraction.

Scale-up and biomass hold-up characteristics of biological fluidized bed reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 353-360 ◽  
Author(s):  
I. Ozturk ◽  
M. Turan ◽  
A. H. Idris
Keyword(s):  
Fluidized Bed ◽  
Scale Up ◽  
Experimental Studies ◽  
Scaling Up ◽  
Pilot Scale ◽  
Fluidized Bed Reactors ◽  
Biofilm Thickness ◽  
Study Results ◽  
Scaling Down ◽  
Comprehensive Study

This paper presents a comprehensive study results on scale-up and biomass hold-up characteristics of biological fluidized bed reactors (BFBR). The overall objective of this study was to establish and test some basic design criteria for the scaling-up or scaling-down of anaerobic fluidized bed reactors. A 12.5 1 laboratory-scale fluidized bed was designed and constructed based on a geometrically similar 70 1 pilot scale fluidized bed and the process performances were compared. Biomass hold up characteristics of the BFBRs were also investigated during the experimental studies. A general expression was developed for predicting the biological fludized bed porosities. Using this expression, both the local and overall fluidized bed porosities could be predicted depending on biofilm thickness, expansion coefficient, media diameter and density. The validity of this expression was tested with the data from this study.

Effect of gas extraction on the hydrodynamics in a fluidized bed membrane reactor at elevated temperatures

2019 ◽  
Vol 14 (4) ◽  
Author(s):  
Yao Xiao ◽  
Chenxi Bai ◽  
Yumin Chen ◽  
Weijie Yan ◽  
Jizhi Du ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Membrane Reactor ◽  
Elevated Temperatures ◽  
Gas Extraction

Particle pressures in gas-fluidized beds

1991 ◽  
Vol 227 ◽  
pp. 495-508 ◽  
Author(s):  
Charles S. Campbell ◽  
David G. Wang
Keyword(s):  
Fluidized Bed ◽  
Bubble Size ◽  
Fluidized Beds ◽  
Particle Density ◽  
Surface Force ◽  
Gas Velocity ◽  
Fluid Forces ◽  
Minimum Fluidization ◽  
Particle Pressure ◽  
Gas Fluidized Beds

The particle pressure is the surface force that is exerted due to the motion of particles and their interactions. This paper describes measurements of the particle pressure exerted on the sidewall of a gas-fluidized bed. As long as the bed remains in a packed state, the particle pressure decreases with increasing gas velocity as progressively more of the bed is supported by fluid forces. It appropriately reaches a minimum fluidization and then begins to rise again when the bed is fluidized, reflecting the agitation of the bed by bubbles. In this fully fluidized region, the particle pressure scales with the particle density and the bubble size.

scholarly journals Effect of Particle Size on Carbon Nanotube Aggregates Behavior in Dilute Phase of a Fluidized Bed

Processes ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 121 ◽  
Author(s):  
Sung Kim
Keyword(s):  
Particle Size ◽  
Carbon Nanotube ◽  
Fluidized Bed ◽  
Laser Sheet ◽  
Scale Up ◽  
Experimental Parameter ◽  
Aggregate Size ◽  
Chemical Vapor ◽  
Gas Velocity ◽  
Effect Of Particle Size

Fluidized bed reactors have been increasingly applied for mass production of Carbon Nanotube (CNT) using catalytic chemical vapor deposition technology. Effect of particle size (dp = 131 μm and 220 μm) on fluidization characteristics and aggregation behavior of the CNT particles have been determined in a fluidized bed for its design and scale-up. The CNT aggregation properties such as size and shape were measured in the dilute phase of a fluidized bed (0.15 m-ID × 2.6 m high) by the laser sheet technique for the visualization. Two CNT particle beds showed different tendency in variations of the aggregates factors with gas velocity due to differences in factors contributing to the aggregate formation. The CNT particles with a larger mean size presented as relatively larger in the aggregate size than the smaller CNT particles at given gas velocities. The aggregates from the large CNT particles showed a sharp increase in the aspect ratio and rapid decrease in the roundness and the solidity with gas velocity. A possible mechanism of aggregates formation was proposed based on the variations of aggregates properties with gas velocity. The obtained Heywood diameters of aggregates have been firstly correlated with the experimental parameter.

Fluidized bed gasification of eucalyptus chips: Axial profiles of syngas composition in a pilot scale reactor

Energy ◽  
2021 ◽  
Vol 219 ◽  
pp. 119604
Author(s):  
Francesco Parrillo ◽  
Filomena Ardolino ◽  
Gabriele Calì ◽  
Davide Marotto ◽  
Alberto Pettinau ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Pilot Scale ◽  
Pilot Scale Reactor ◽  
Scale Reactor

scholarly journals Pilot-Scale Production of Chito-Oligosaccharides Using an Innovative Recombinant Chitosanase Preparation Approach

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 290
Author(s):  
Chih-Yu Cheng ◽  
Chia-Huang Tsai ◽  
Pei-Jyun Liou ◽  
Chi-Hang Wang
Keyword(s):  
Cell Density ◽  
Scale Up ◽  
Cost Effective ◽  
Pilot Scale ◽  
Ionic Concentration ◽  
Dihydrogen Phosphate ◽  
Scale Production ◽  
Sodium Dihydrogen Phosphate ◽  
Selective Precipitation ◽  
Pilot Scale Production

For pilot-scale production of chito-oligosaccharides, it must be cost-effective to prepare designable recombinant chitosanase. Herein, an efficient method for preparing recombinant Bacillus chitosanase from Escherichia coli by elimination of undesirable substances as a precipitate is proposed. After an optimized culture with IPTG (Isopropyl β-d-1-thiogalactopyranoside) induction, the harvested cells were resuspended, disrupted by sonication, divided by selective precipitation, and stored using the same solution conditions. Several factors involved in these procedures, including ion types, ionic concentration, pH, and bacterial cell density, were examined. The optimal conditions were inferred to be pH = 4.5, 300 mM sodium dihydrogen phosphate, and cell density below 1011 cells/mL. Finally, recombinant chitosanase was purified to >70% homogeneity with an activity recovery and enzyme yield of 90% and 106 mg/L, respectively. When 10 L of 5% chitosan was hydrolyzed with 2500 units of chitosanase at ambient temperature for 72 h, hydrolyzed products having molar masses of 833 ± 222 g/mol with multiple degrees of polymerization (chito-dimer to tetramer) were obtained. This work provided an economical and eco-friendly preparation of recombinant chitosanase to scale up the hydrolysis of chitosan towards tailored oligosaccharides in the near future.

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