scholarly journals Effect of Fines Content on Fluidity of FCC Catalysts for Stable Operation of Fluid Catalytic Cracking Unit

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 293 ◽  
Author(s):  
Sung Kim ◽  
Chae Yeo ◽  
Do Lee
Keyword(s):  
Fluidized Bed ◽  
Catalytic Cracking ◽  
Particle Diameter ◽  
Fluidized Bed Reactor ◽  
Fluid Catalytic Cracking ◽  
Stable Operation ◽  
Minimum Fluidization Velocity ◽  
Fines Content ◽  
Fluidization Velocity ◽  
Fcc Catalysts

Effect of fines content (weight % of particles with diameter less than 45 μm) on bed fluidity was determined to get a base for good fluidization quality in the fluid catalytic cracking (FCC) unit. The fines content in equilibrium FCC catalysts (Ecat) from commercial units were controlled by adding or removing the fines to simulate commercial situation. To get the fluidity values (Umb/Umf) of seven different FCC catalysts (2 Ecats and 5 fresh catalysts) and their mixture, minimum fluidization velocity (Umf) and minimum bubbling velocity (Umb) were measured in a fluidized bed reactor (0.05 m ID). The fluidity decreased with loss of fines content and increased with increments of makeup of fresh catalysts or additive with the controlled fines content. The fluidities of catalysts increase with increases of normalized particle diameter variation by the fines addition. The obtained fluidities have been correlated with the fines contents and the catalyst and gas properties. The proposed correlation could guide to keep good catalyst fluidity in the FCC unit.

Correlation for Prediction of Minimum Fluidization Velocity and Riser Liquid Holdup in Three-Phase External Loop Air Lift Fluidized Bed Reactor

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Sivakumar Venkatachalam ◽  
Kannan Kandasamy ◽  
Senthilkumar Kandasamy
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Solid Particles ◽  
Liquid Holdup ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
External Loop ◽  
Minimum Fluidization ◽  
Newtonian Liquids ◽  
Air Lift

The effect of superficial gas and liquid velocities and properties of solids on the minimum fluidization velocity and riser liquid holdup of a three-phase external loop air lift fluidized bed reactor was characterized using Newtonian and non-Newtonian systems. Water, 65% and 85% of glycerol and n-Butanol were used as Newtonian liquids and different concentrations of carboxymethyl cellulose (i.e. 0.2%, 0.5% and 1% CMC) were used as non-Newtonian liquids. Spherical glass beads, bearl saddles and rasching rings of different sizes were used as solid phases. The phase flow rates and properties of solid particles had significant effects on the hydrodynamic characteristics of the external loop air lift fluidized bed reactor, such as minimum fluidization velocity and riser liquid holdup. Unified correlations have been developed to estimate the minimum fluidization velocity and riser liquid holdup as a function of superficial phase velocities, properties of solid particles and physical properties of both Newtonian and non-Newtonian liquid systems. The predicting ability of the correlations were tested with the experimental data and found to be a good fit with an absolute average relative deviation (AARD) of ± 6.5 % and ± 7.8 % for minimum fluidization velocity and riser liquid holdup, respectively.

Fluidization characteristics of wide-size-distribution particles in a gas-solid fluidized bed reactor

2020 ◽  
Vol 18 (12) ◽  
Author(s):  
Chaojie Li ◽  
Weiwen Wang ◽  
Xiuling Guo ◽  
Jihai Duan
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Fluidized Bed ◽  
Particle System ◽  
Fluidized Bed Reactor ◽  
Minimum Fluidization Velocity ◽  
Fluidization Velocity ◽  
Minimum Fluidization ◽  
Wide Size Distribution

AbstractFluidization characteristics of wide-size-distribution particles in the gas-solid fluidized bed reactor are investigated by applying experiment and computational fluid dynamics (CFD) methods. In this study, three types of narrow-cut particles and two sets of wide-size-distribution particles are used. A model considering particle size distribution is developed in the Eulerian frame, and good agreement between numerical results and experimental data is observed. The particle size distribution has an important effect on the average bed voidage. The axial particle diameter profiles along bed height have a “S” type feature. Minimum fluidization velocity is determined from the standard deviation of pressure fluctuations and bubble dynamics are analyzed based on power spectra. Results indicate that fine particle composition can reduce the minimum fluidization velocity of wide-size-distribution particle system and the bubble diameter in the fluidized bed.

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