Radioactive particle tracking in a lab‐scale conical fluidized bed dryer containing pharmaceutical granule

Khanna, Pankaj; Pugsley, Todd; Tanfara, Helen; Dumont, Hubert

doi:10.1002/cjce.20073

Cited by 15 publications

(12 citation statements)

References 46 publications

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“…No internal inside the vessel None result is the average number of 'counts', c i (counts are proportional to the amount of radioactive -rays that make a way into a detector's crystal), for each sensor in a period of 0.50 s. In order to minimise the errors by the reduction of the radiation of the tracer particle in time, Khanna et al (2008) proposed a normalisation of the data. The counts are normalised using C = 12 1 c i , and the relative signal value is obtained as:…”

Section: Accuracy In Experimental Detection Of a Tracer-particle Locamentioning

confidence: 99%

“…In order to evaluate the accuracy of the RPT technique, the tracer-particle was introduced in a long shaft that was rotating by an electric motor ( Figure 6). An E/G tracer particle prepared as suggested by Godfroy (1997) and Khanna et al (2008) was selected as the radioactive source. When gold is radiated in a nuclear reactor (for this case, the Slowpoke II reactor at the Saskatchewan Research Council), part of it is transformed into the Au 198 isotope with a half-life of 2.69 days (Chaouki et al, 1997).…”

Section: Accuracy In Experimental Detection Of a Tracer-particle Locamentioning

confidence: 99%

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Application of radioactive particle tracking to indicate shed fouling in the stripper section of a fluid coker

Sánchez¹,

Granovskiy²

2012

Can J Chem Eng

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The stripper section of a fluid-coker consists of a system of baffles (sheds) that enhances the removal efficiency of entrained and adsorbed hydrocarbons from the fluidised coke-particles. If the particles contain a thin liquid film layer of heavy hydrocarbons, making them excessively 'wet' or 'sticky', and if they stay in contact with sheds for too long, solid deposits are formed that lead to stripper fouling. Extensive fouling decreases stripping efficiency and liquid product yield and can shorten run-times between shutdowns. Because of the fouling, the shape of sheds mostly changes by increasing their surfaces thickness. An early indication of that fouling and the ability to follow its development are essential for choosing optimal parameters of the process. The radioactive particle tracking (RPT) method has been tested to determine its applicability to indicate the change in the shape of internals within a fluidised bed reactor when direct observation is impossible. A single radioactive tracer-particle has been traced in experiments lasting from 2 to 6 h. The experiments were conducted in a lab-scale, cold-flow fluidised bed into which a single shed with walls of different thickness was incorporated. This experimental fluidised bed provides intensive solid phase mixing that allows a single tracer-particle to be located in any place within the reactor. By registering the frequency of the tracer-particle appearance within a defined internal space surrounding the shed, the shape of shed was reconstructed. The conducted experiments suggest that RPT technique allows for tracking internals' fouling within a fluidised bed reactor.

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Section: Accuracy In Experimental Detection Of a Tracer-particle Locamentioning

confidence: 99%

Section: Accuracy In Experimental Detection Of a Tracer-particle Locamentioning

confidence: 99%

Application of radioactive particle tracking to indicate shed fouling in the stripper section of a fluid coker

Sánchez¹,

Granovskiy²

2012

Can J Chem Eng

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“…This same type of circulation pattern has also been reported by our group. Khanna et al [16] used a radioactive particle tracking (RPT) system to describe conical bed circulation patterns with a bed of dry pharmaceutical granule. More importantly however, our group has also demonstrated the circulation patterns generated during the actual drying of pharmaceutical granule.…”

Section: Introductionmentioning

confidence: 99%

“…First, conical fluidized beds are operated with distributor plates, whereas the spouted beds use an orifice to introduce gas into the bed. Second, conical fluidized beds typically operated with Geldart A and B powders [14][15][16][17][18][19]; whereas true spouted bed operation results from the use of Geldart D powders [20][21][22]. Finally, conical fluidized beds are usually operated at relatively shallow static bed heights as compared to their inlet diameter (H/D i ≤ 1).…”

Section: Introductionmentioning

confidence: 99%

The influence of vessel geometry on fluidized bed dryer hydrodynamics

Wormsbecker¹,

Ommen²,

Nijenhuis³

et al. 2009

Powder Technology

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“…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.…”

mentioning

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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Radioactive particle tracking in a lab‐scale conical fluidized bed dryer containing pharmaceutical granule

Cited by 15 publications

References 46 publications

Application of radioactive particle tracking to indicate shed fouling in the stripper section of a fluid coker

Application of radioactive particle tracking to indicate shed fouling in the stripper section of a fluid coker

The influence of vessel geometry on fluidized bed dryer hydrodynamics

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

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