Comparative study of gas–solids flow patterns inside novel multi-regime riser and conventional riser

Zhu, Xiaolin; Yang, Chaohe; Li, Chunyi; Liu, Yibin; Wang, Lu; Li, Teng; Geng, Qingbo

doi:10.1016/j.cej.2012.10.067

Cited by 34 publications

(11 citation statements)

References 43 publications

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“…The phase interface structure composed of internal pure gas and external mixtures can be observed. Differing from the ring-core structure of risers, [29] the phase interface structure [30] is specific to gradient reactors, which is beneficial to the cracking of heavy gases and the recovery of light gas products.…”

Section: Model Validationmentioning

confidence: 99%

Numerical analysis of hydrodynamic characteristics and interphase coupling in a gas‐solid cyclone reactor

Wang

Zhu

et al. 2021

Can J Chem Eng

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A down-flow gas-solid cyclone reactor (GSCR) for fluidized catalytic cracking process was proposed to solve the side reactions. Comprehensive threedimensional numerical models were established to interpret its gas-solid flow features, where the continuous phase and dispersed phase were modelled in the Eulerian grid and Lagrangian framework, respectively. Simulation results show that the four-way approach has a better prediction of gas-solid flow hydrodynamics in GSCR than the two-way approach, and the numerical pressure drop agreed well with the experimental data. Most catalysts accumulated on the wall when descending and the phase interface structure composed of internal pure gas and external mixtures was subsequently formed. The radial distribution of tangential velocity was almost hump shaped. Tangential and axial kinetic energies accounted for 92.49%-95.45% of total kinetic energy and were thus dominant. In the dilute condition, the oscillatory behaviour of particle concentration was more severe than that of gas velocities, and particle concentration and gas tangential velocity had the same dominant frequency (~2.6 Hz). As the particulate loading increased tenfold, the hydrodynamic characteristics became rather complex.

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Section: Model Validationmentioning

confidence: 99%

Numerical analysis of hydrodynamic characteristics and interphase coupling in a gas‐solid cyclone reactor

Wang

Zhu

et al. 2021

Can J Chem Eng

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“…It was highlighted that nozzle angle larger than A C C E P T E D M A N U S C R I P T 7 30° was preferable. Other recent works that used the CFD technique have reported interesting results on the flow system and chemistry in FCC risers [18][19]. Chen et al demonstrated that an increase in feed spray velocity would facilitate the feed diffusion and consequently enhance gasoil conversion.…”

Section: Introductionmentioning

confidence: 97%

CFD investigation of hydrodynamics, heat transfer and cracking reactions in a large-scale fluidized catalytic cracking riser

Yang

Berrouk²,

et al. 2016

Applied Mathematical Modelling

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investigation of hydrodynamics, heat transfer and cracking reactions in a large-scale fluidized catalytic cracking riser, Applied Mathematical Modelling (2016), 1 Highlights  Hydrodynamics coupled with cracking reactions in an FCC riser were studied. Two-fluid mathematical approach was used to model the fluid-particle flow. Intricate phenomena near a series of injecting nozzles were revealed in detail. A recommendation of an appropriate increasing of the feed injection angle was proposed. Yields and reaction rates of main products and catalyst activity were investigated. ABSTRACTA three-dimensional reactive gas-particle CFD model was built to study the hydrodynamics, heat transfer and cracking reaction behaviors within an industrial Fluid Catalytic Cracking (FCC) riser reactor designed to maximize propylene production. The two-fluid methodology (TFM) was used to simulate the riser hydrodynamics with solid phase properties derived from the kinetic theory of granular flows (KTGF). An 11-lump kinetic model was selected to represent the cracking reaction network in the CFD model. The selection of the kinetic model is dictated by the properties of the feedstock processed and the aim of the process which is maximizing propylene. A novel treatment of the coke component was conducted by incorporating coke into the secondary granular phase which is more realistic since carbon deposition occurs on catalyst phase. Momentum transfer, heat transfer and reaction behavior inside the riser were discussed in detail and inhomogeneity in these aspects were observed especially above the high speed injection nozzles. The numerical results of this investigation show a good agreement with the process real data on the yield distribution despite the use of a coarse grid to mesh such an industrial scale FCC riser. The methodology employed used and the results obtained should serve as guidelines for possible process redesign and optimization.

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“…Geometric structures, numbers, and locations of the enlarged section are variable. Some authors have developed different multistage risers and investigated fundamental gas–solid hydrodynamics in the bed. − They found that gas–solid flow structures change in the multistage riser due to the variation of the riser diameter with the bed height. Kersten et al introduced a novel multistage riser and concluded that the backmixing of gas and solids between the segments was prevented effectively.…”

Section: Introductionmentioning

confidence: 99%

“…Kersten et al introduced a novel multistage riser and concluded that the backmixing of gas and solids between the segments was prevented effectively. Qi et al and Zhu et al investigated the detailed profiles of solid velocity, solid concentration, and local solid flux and analyzed the flow development pattern in multistage beds. Their results showed that the relatively uniform gas–solid flow with high solid concentration was obtained.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Inner Solid Circulation Pattern in the Multistage Riser

Zhang

2021

Ind. Eng. Chem. Res.

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A multistage riser reactor with the enlarged section plays an increasingly important role in industries such as energy conversion. However, gas−solid complex flow in the multistage riser needs to be further explored. Inner solid circulation occurred in the enlarged section exerts essential effects on flow behavior. In this work, inner circulation mechanisms of solids in the multistage riser are investigated experimentally by correlating the bed geometry. Solid streamline and velocity profiles show that the inner circulation in the enlarged section involves the vortex core part in the upstream region and the expansion part in the downstream region. For the vortex core part, single and dual circulations of solids occur in different enlarged sections. The results also indicate that vortex core motions tend to strengthen with the increase of the diameter ratio and height−diameter ratio but weaken with the increase of the angle. Moreover, the effects of the expansion part on gas−solid flow increase as the angle increases.

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Comparative study of gas–solids flow patterns inside novel multi-regime riser and conventional riser

Cited by 34 publications

References 43 publications

Numerical analysis of hydrodynamic characteristics and interphase coupling in a gas‐solid cyclone reactor

Numerical analysis of hydrodynamic characteristics and interphase coupling in a gas‐solid cyclone reactor

CFD investigation of hydrodynamics, heat transfer and cracking reactions in a large-scale fluidized catalytic cracking riser

Experimental Study of the Inner Solid Circulation Pattern in the Multistage Riser

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