Dual-dense gas-solid circulating fluidized bed reactor

Gai, Hengjun; Yang, Peiyi; Zhang, Qiang; Lin, Mengqi; Song, Hongbing; Xiao, Meng; Huang, Ting‐Ting; Zhu, Quanhong

doi:10.1016/j.fuel.2022.126872

Cited by 10 publications

(3 citation statements)

References 72 publications

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“…It can be seen clearly in Figure 10 that the solid particles in the high-speed bed enter the low-speed bed from the connecting hole in the upper part of the high-speed bed, while the solid particles in the low-speed bed enter the high-speed bed from the connecting hole in the lower part of the low-speed bed, which shows that the internal recycling is achieved between the two beds. Moreover, there are several flow vortexes formed in the beds, which can enhance mass transfer between the gas phase and the solid phase [44,45].…”

Section: Velocity Profiles Of Solid Phasementioning

confidence: 99%

Fluid Dynamics Investigation in a Cold Flow Model of Internal Recycle Quadruple Fluidized Bed Coal Pyrolyzer

Cao,

Yu,

Wang

et al. 2024

Processes

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Internal recycle quadruple fluidized bed pyrolyzer (IR-QFBP) consists of a dual fluidized bed pyrolyzer and a dual fluidized bed combustor and is proposed in this work. It is a new kind of efficient fluidized bed with high pyrolysis and energy efficiency. IR-QFBP may attract extensive attention because of its compact structure. Cold hydrodynamic characteristics of IR-QFBP are the bases of modeling and designing for the hot one. To fully understand the hydrodynamic characteristics of IR-QFBP, a cold flow model on a laboratory scale was designed and set up; furthermore, the two-fluid model (TFM) based simulation was also carried out. The pressure profiles, fluidization states, velocity profiles, and circulation rates of a solid powder at different operation conditions in IR-QFBP were investigated. The results showed that the stable internal circulation of solid powder can be achieved in IR-QFBP. And different circulation characteristics can be obtained by adjusting the operating conditions.

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Section: Velocity Profiles Of Solid Phasementioning

confidence: 99%

Fluid Dynamics Investigation in a Cold Flow Model of Internal Recycle Quadruple Fluidized Bed Coal Pyrolyzer

Cao,

Yu,

Wang

et al. 2024

Processes

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“…Recently, we proposed to integrate the gas–solid MSB with the dual-dense circulating fluidization process, , which is illustrated in Figure b. After the saturated/deactivated particles in the MSB flowed into the lower part of the ascending bed through the bottom opening, they were first regenerated by the influent gas and then sent back to the upper part of the MSB through the upper opening based on the overflow.…”

Section: Introductionmentioning

confidence: 99%

Discharge of Packed Magnetizable Particles through Side Orifice in the Absence and Presence of a Magnetic Field

Liu,

Guan,

Zhang

et al. 2024

Ind. Eng. Chem. Res.

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The magnetizable and active particles in the magnetically stabilized bed (MSB) should be regenerated in time to ensure the continuous treatment of the influent gas. We proposed solving this problem by integrating the MSB with the dual-dense gas–solid circulating fluidization technique. In this case, laws governing the discharge of magnetizable particles from the MSB through the side opening should be mastered. The discharging behavior of packed iron particles through the side orifice was first explored. The mass discharge rate (q) was constant over time and increased as the orifice size or particle size increased. The angle of repose (β) at the end of the discharge decreased with increasing orifice size or particle size. Smaller particles usually had greater inherent interparticle forces and poorer flowability. After the axial uniform and steady magnetic field was exerted, q decreased, whereas β increased as the field intensity (H) increased. Both variations became steeper at higher values of H. The magnetic field induced additional interparticle forces and decreased the flowability of the magnetizable particles. After H exceeded a certain value, the packed iron particles were magnetically frozen and ceased to flow out of the orifice. Under the action of the magnetic field, the discharge of packed magnetizable particles through the side orifice could also be predicted by the well-known Beverloo equation; the effect of H could be well-reflected by k embedded therein. k was demonstrated to be more comprehensive than various repose angles in characterizing the flowability of packed particles through orifices.

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“…Fluidized bed reactors have become widely recognized and essential in various industrial applications. The reactors under consideration, distinguished by solid particles suspended in a gaseous medium, have garnered significant attention due to their distinct benefits in various applications, from petrochemical processing to producing renewable energy [1][2][3]. Fluidized beds are widely recognized for their exceptional mixing properties, remarkable heat transfer capabilities, and improved mass transfer rates [4,5].…”

Section: Introductionmentioning

confidence: 99%

Nano-Iron Oxide Coating for Enhanced Heat Transfer in Gas–Solid Fluidized Bed Systems

Faraj,

Ali,

Najim

et al. 2024

ChemEngineering

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This study explores using iron oxide coatings on glass beads to improve heat transfer efficiency in fluidized bed reactors. Techniques such as BET surface area analysis, SEM imaging, and X-ray diffraction were used to characterize the coated beads. Results showed the successful creation of a crystalline iron layer on the beads’ surface and increased thermal conductivity, especially at elevated temperatures. The study also quantified the impact of air surface velocity and heating power on the heat transfer coefficient, revealing substantial improvements, especially at higher velocities. It was found that the heat transfer coefficient for 600 µm glass beads increases significantly from 336.4 W/m2·K to 390.3 W/m2·K when the velocity is 0.27 m/s and the heating flux is 125 W. This demonstrates the effectiveness of the iron oxide coating in improving heat transfer. The results of this study emphasize the efficacy of iron oxide coatings in augmenting heat transmission characteristics, particularly in fluidized bed reactor.

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Dual-dense gas-solid circulating fluidized bed reactor

Cited by 10 publications

References 72 publications

Fluid Dynamics Investigation in a Cold Flow Model of Internal Recycle Quadruple Fluidized Bed Coal Pyrolyzer

Fluid Dynamics Investigation in a Cold Flow Model of Internal Recycle Quadruple Fluidized Bed Coal Pyrolyzer

Discharge of Packed Magnetizable Particles through Side Orifice in the Absence and Presence of a Magnetic Field

Nano-Iron Oxide Coating for Enhanced Heat Transfer in Gas–Solid Fluidized Bed Systems

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