Slip velocity and axial dispersion measurements in a gas-solid pipeline using particle tracer analysis

Tallon, Stephen; Davies, Clive E; Barry, B.

doi:10.1016/s0032-5910(98)00095-3

Cited by 13 publications

(4 citation statements)

References 4 publications

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“…For a fast fluidized bed reactor, the catalysts residence time is less than the turbulent fluidized bed reactor. Previous works , pointed out that in a fast fluidized bed reactor the catalysts concentration follows a typical core-annulus distribution. Catalysts in the annulus zone tend to flow downward, which makes the flow pattern deviate from plug flow.…”

Section: Experiments Resultsmentioning

confidence: 99%

Investigation of Pyridine Synthesis in a Fast Fluidized Bed Reactor

Zhou

Liu

et al. 2018

Ind. Eng. Chem. Res.

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Pyridine has been generally synthesized by aldehydes and ammonia in a turbulent fluidized bed reactor. In this paper, a fast fluidized bed reactor was proposed for pyridine synthesis. Experiment results show that the yields of pyridine and 3-picoline decrease while the selectivity of pyridine over 3-picoline is increased. A model was proposed to predict the performance of the fast fluidized bed reactor; the average prediction deviation is 6%. The influence of mass transfer, heat transfer, and backmixing of the gas phase is represented by a modification factor, and the mean value of this modification factor is 0.75 within the experimental operating conditions. By model prediction, the reaction should be terminated when the critical point of R2 is reached to avoid over-reaction. To optimize the pyridine and 3-picoline product yield and minimize coke product yield, the reaction temperature should be kept around 723 K.

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Section: Experiments Resultsmentioning

confidence: 99%

Investigation of Pyridine Synthesis in a Fast Fluidized Bed Reactor

Zhou

Liu

et al. 2018

Ind. Eng. Chem. Res.

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“…The use of sound measurement in solids flows has been explored by Davies and Tallon [62][63][64]. The sound wave intensity is propagated by the presence of solids, giving a direct relationship to the amount of solids flowing.…”

Section: Flow Measurementsmentioning

confidence: 99%

Recent Advancement in Pneumatic Conveying for Application in Feed Industry: A Review

2023

Preprint

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The transportation of feed pellets via pneumatic conveying plays an improtant role in feed industry. In recent years, many efforts are made both exprimentally and numerically to gain a better understanding of the underlying mechanism for pneumatic conveying. Though few of those research is directly related to feed pellets, it can be beneficial to draw a full picture of rencent development in pneumatic conveying, with emphasis on aspects extendable to feed transportation. This paper reviews first the major factors concerning feed pellets pneumatic conveying, such as particle breakage, pipe wear and electrostatic. Building on that, new advancement including emerging new technologies in experiments and simulations are discussed, with a focus on the experimental measurements and mathematical models, repectively. The needs for future research and the analogy to feed pellets tranportation is given lastly.

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“…48,49 Finally, a third approach is to inject a few labeled tracer particles and measure their velocities experimentally. 48 The main objective here is to develop a CFD model for describing the hydrodynamics of a conical fluidized bed. Accordingly, the optical fiber technique is used as a first step to provide a set of experimental data for axial solid velocity in different sections of a bench-scale conical fluidized bed containing polydispersed dried TiO 2 particles.…”

Section: Introductionmentioning

confidence: 99%

“…4,13,16,32,50 Alternatively, slip velocity is estimated either experimentally or numerically from the difference between gas and solid particle velocities. 48,49 Finally, a third approach is to inject a few labeled tracer particles and measure their velocities experimentally. …”

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confidence: 99%

Effect of slip boundary conditions on the simulation of microparticle velocity fields in a conical fluidized bed

2013

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The hydrodynamic performance of micrometric TiO 2 particles has been experimentally studied in a conical fluidized bed and the results compared with numerical simulations. Local solid velocities in the bed have been measured by means of an optical fiber technique under different operating conditions of particle loading and air velocity. The radial profiles of axial solid velocities have been simulated to assess the sensitivity of grid size, and different drag models, namely, those by Syamlal and O'Brien, Ahmadi and Ma, Arastoopour et al., and Gidaspow, for no-slip, partial-slip, and free-slip boundary conditions (BCs). The different drag models record almost similar results, but those provided by the Gidaspow and Ahmadi-Ma models, together with free-slip BCs, are in somewhat better agreement with the experimental data for conical fluidized beds with smooth walls. V C 2013 American Institute of Chemical Engineers AIChE J, 59: [4502][4503][4504][4505][4506][4507][4508][4509][4510][4511][4512][4513][4514][4515][4516][4517][4518] 2013 Keywords: conical fluidized bed, solid velocity, slip boundary conditions, numerical simulation, drag models IntroductionFluidized and spouted beds are extensively used for various industrial applications in pharmaceuticals, 1,2 drying, 3,4 food processing, 5 combustion, 6,7 pyrolysis, and catalytic polymerization. 8,9 A conical fluidized bed has the characteristics of both fluidized and spouted beds, being, therefore, suitable for handling agglomerating or sticky powders. This is particularly the case for the fluidization of fine particles with a wide size distribution corresponding to different groups of Geldart's classification. 10,11 Although many studies have been reported in the literature involving fluidized beds, [12][13][14][15] certain details of the hydrodynamic performance of conical fluidized beds are not fully understood, which is partially due to the few experimental data on the hydrodynamics of these beds. 16,17 Accordingly, the design and scaling-up of conical fluidized beds is not straightforward, given that bed geometry, the ratio of inlet diameter to bed height and operating conditions highly influence gas-solid flow regime. Furthermore, hydrodynamic parameters such as pressure drop, solid volume fraction, and velocity significantly affect the performance of the conical bed. Optimizing the performance of conical fluidized beds requires a thorough understanding of the mixing characteristics and interactions between the gas and solid phases. The standard noninvasive measurement techniques used for the determination of particle trajectories and velocities are as follows: pitot tube, 18 Laser-Doppler anemometry, 19 video technique, 20 radioactive particle tracking, 21 and particle image velocimetry. 22 Nevertheless, techniques based on an optical-fiber probe are also promising for this purpose. [23][24][25][26][27][28][29] In recent years, with the development of high performance computers, researchers have used numerical methods to study the flow behavior of fluidized...

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Slip velocity and axial dispersion measurements in a gas-solid pipeline using particle tracer analysis

Cited by 13 publications

References 4 publications

Investigation of Pyridine Synthesis in a Fast Fluidized Bed Reactor

Investigation of Pyridine Synthesis in a Fast Fluidized Bed Reactor

Recent Advancement in Pneumatic Conveying for Application in Feed Industry: A Review

Effect of slip boundary conditions on the simulation of microparticle velocity fields in a conical fluidized bed

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