Numerical study of counter‐current gas–solid flow in FCC disengager and stripper

Jia, Dening; Zhao, Hui; Berrouk, Abdallah S.; Yang, Chaohe; Shan, Honghong

doi:10.1002/cjce.21811

Cited by 14 publications

(2 citation statements)

References 21 publications

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“…Within the experimental range, yields of the tar kept increasing, but the coal gas decreased. Counter-current downers were also adopted in fluid catalytic cracking (FCC) by Jia et al, 13 and dual circulating fluidized bed gasifiers by Schmid et al 14 Geometrical modifications have been further conducted. Peng et al 15 applied computational fluid dynamics (CFD) simulation to clarify the characteristics of countercurrent downers.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Flash Ironmaking Process in a Newly Proposed Counter-Current Downer

Yang

Shen

et al. 2021

JOM

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A counter-current downer is proposed as a new structure to improve the flash ironmaking technology (FIT). A computational fluid dynamics (CFD) model was established to predict the dilute gas-particle reacting flow, and a coreannulus structure was observed. Furthermore, counter-current and cocurrent downers have been compared in similar conditions. As a result, reduced iron of the counter-current downer had a higher reduction degree (99.8%) than that of the cocurrent downer (70.1%). The first two reaction steps (Fe 2 O 3 fi Fe 3 O 4 and F 3 O 4 fi FeO) were swift, while the subsequent step (FeO fi Fe) in the counter-current downer showed a significant difference due to the preponderant reduction potential and temperature. Different gas velocities (0.167-0.667 m/s) were also investigated, and the high-speed gas flow brought more particles with decreasing metal yield from 89.3% to 27.5%. However, more gas amounts always led to a higher reduction degree separately of captured and escaped particles.

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Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Flash Ironmaking Process in a Newly Proposed Counter-Current Downer

Yang

Shen

et al. 2021

JOM

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“…A lot of holes or grids are opened in the baffles to make the contact of catalysts uniformly with vapor. But the baffle stripper also meets several problems in the practical application, such as coking 12, flooding 13, wear 14, and local defluidization 15. These problems decrease its stripping efficiency.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Gas‐Solids Contact in an Industrial Multistage Circulation Stripper

Yao

Liu

2021

Chem Eng & Technol

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An industrial multistage circulation stripper (MSCS) is simulated to improve its stripping efficiency. In its baffle region, an amount of vapor is easily to be gathered under the baffle and forms the vapor bypass near the walls. The comparison of the vapor flux at each row of holes indicates that the reason is an improper hole layout in the baffles. A method of hole layout to improve the vapor‐particles contact is built based on the Bernoulli equation. The enhanced baffles can decrease the average standard deviation from 0.1783 to 0.0056 and improve the stripping efficiency in the downer baffle region. The vapor distribution in the baffles perfecting the hole layout is sensitive to the superficial gas velocity but not to the mass flow rate of particles.

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Investigation of fluidized bed behaviour using electrical capacitance tomography

et al. 2020

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The temporal and cross-sectional distributions of particles in a 127 mm diameter fluidized bed have been obtained using a new generation, high-speed Electrical Capacitance Tomography. Two planes of eight electrodes were used and mounted at 160 and 660 mm from the gas distributor which was a 3 mm thick porous plastic plate made (maximum pore size of 50-70 m). 3 mm diameter, nearly-spherical polyethylene granules made up the bed. Experiments at sampling frequencies of 200-2000 cross-sections per second and gas superficial velocities from just below the minimum fluidization to 83% above minimum fluidization velocities were used. The time series of the cross-sectional average void fractions have been examined both directly and in amplitude and frequency space. The last two used Probability Density Functions and Power Spectral Densities. The information generated show that the fluidized bed is operating in the slugging mode, not surprising given the size of the particles. It has been found that an increase of the excess gas velocity above the minimum fluidization velocity resulted in the increase of the mean void fraction, length and velocity of the slug bubbles as well as the bed height, and in a slight decrease of the slug frequency. The results are presented in a level of detail suitable for comparison with later numerical simulation.

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Numerical study of counter‐current gas–solid flow in FCC disengager and stripper

Cited by 14 publications

References 21 publications

Numerical Analysis of Flash Ironmaking Process in a Newly Proposed Counter-Current Downer

Numerical Analysis of Flash Ironmaking Process in a Newly Proposed Counter-Current Downer

Optimization of Gas‐Solids Contact in an Industrial Multistage Circulation Stripper

Investigation of fluidized bed behaviour using electrical capacitance tomography

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