Investigation of the kinetic laws affecting the organic suspension granulation in the fluidized bed

Ostroha, Ruslan; Yukhymenko, Mykola; Yakushko, S; Аrtyukhov, Аrtem

doi:10.15587/1729-4061.2017.107169

Cited by 10 publications

(5 citation statements)

References 10 publications

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“…5), which shows a monotonous increase in the thickness of the shell dependent on the diameter of the retour particles. However, the mode of growth of granules on their surface is possible under certain temperature conditions [20], with a deviation from which new small granules are formed in the layer, or their agglomeration occurs.…”

Section: Discussion Of Results Of the Analytical Study Into The Influence Of Regime And Technological Parameters On The Encapsulation Promentioning

confidence: 99%

Determining the main regularities in the process of mineral fertilizer granule encapsulation in the fluidized bed apparatus

Ostroha

Yukhymenko

Bocko

et al. 2021

EEJET

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This paper has substantiated the expediency and prospects of obtaining organomineral fertilizers by encapsulating mineral granules with an organic suspension in fluidized bed apparatuses. An overview of existing approaches to the mathematical description of the kinetics of granule growth in granulation processes in fluidized bed apparatuses is presented. A mathematical model of the kinetics of the formation of a hard shell around granules in a fluidized bed has been built. It shows that the kinetics depend on the size of the retour particles, the specific flow rate of the suspension, the density of the suspension and granules, and the time of the process. Equations have been derived for determining the thickness of the hard shell and the specific flow rate of the suspension for individual granulation stages in a multi-stage granulator of the fluidized layer. Analytically, graphical dependences were built, which showed an increase in the thickness of the hard shell due to an increase in the specific flow rate of the suspension, the diameter of the retour particles, and the time of the encapsulation process. The equations make it possible to determine the rational regime and technological parameters of the encapsulation process in order to obtain a coating of the predefined thickness at the surface of the granules. This ensures that a quality product is obtained, with a granulometric composition in a narrower range of particle size. To obtain granules of 2.5–4 mm in size, it is necessary to carry out the process in three- or four-stage granulators of the fluidized bed at specific suspension consumption of (10–20)∙10-4 kg/(kg∙s.). It is shown that with uniform growing of granules with a constant increase in the thickness of the shell in multistage granulators, the suspension consumption decreases by 2‒3 times from the first stage to the subsequent ones. This approach reduces the operating and energy costs of the process.

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Section: Discussion Of Results Of the Analytical Study Into The Influence Of Regime And Technological Parameters On The Encapsulation Promentioning

confidence: 99%

Determining the main regularities in the process of mineral fertilizer granule encapsulation in the fluidized bed apparatus

Ostroha

Yukhymenko

Bocko

et al. 2021

EEJET

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“…In view of the need to isolate small fractions in technologies for obtaining granular mineral fertilizers, it is necessary to install a pneumatic classifier after the granulator [21]. As the above review shows, the main designs of pneumatic classifiers are apparatuses of the mine type with a free cross-section (such as a pneumatic pipe) and a fluidized layer.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Design of a shelf pneumatic classifier for separating a polydisperse mixture of granulated superphosphate

Yukhymenko

Ostroha

Bocko

2022

EEJET

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The object of this study is a polydisperse mixture of granular superphosphate. It is emphasized that existing technologies of granulation and processing of granules lead to the formation of dusty fractions of small particles. The content of small fractions in the finished product should be minimal and, in connection with this problem, the task is to remove small particles from the mixture. The purpose of the current experimental study is to classify a polydisperse mixture of granular superphosphate in a pneumatic classifier. The device includes an inclined perforated shelf with an unloading space between its end and the wall of the apparatus. It has been experimentally revealed that the maximum efficiency of extraction into the entrainment of small particles is achieved with a width of the discharge space equal to 0.5 of the length of the cross-sectional side of the apparatus; the degree of perforation of the shelf is 5 %; the angle of inclination of the shelf is 25–30°; the speed of the gas flow in the free section of the apparatus is 3.7 m/s. It is shown that the degree of extraction into the entrainment of a small fraction less than 1 mm in size reaches 70–75 %, the content of the small fraction in the carry-over is 96–98 %, and the large fraction is less than 5 %. By processing experimental data, an empirical equation was built that makes it possible to determine the concentration of particles in the gas stream for individual fractions of the material. It is shown that due to the implementation of an active aerodynamic weighing mode, the shelf pneumatic classifier works at specific loads for air flow rate less than the typical designs of fluidized bed separators. It is noted that the effective operation of the shelf pneumatic classifier in the production of granular mineral fertilizers is ensured at a productivity of no more than 10–12 t/h. With greater productivity, there is a need to install several devices in the technological line

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“…However, it requires a separate supply of gas flow into the holes of the gas distribution grid and the nozzle in its center. In some fluidized bed granulators, a special spraying mode of the melt by the nozzle is formed [4,5], or a fluidization jet-pulsating mode is created [6].…”

Section: Literature Reviewmentioning

confidence: 99%

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

et al. 2021

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The article deals with the theoretical description and experimental study of the hydrodynamic and heat transfer properties regarding the operation of multistage gravitational devices of the fluidized bed with inclined perforated shelves. The peculiarities of the work and the implementation field of the multistage shelf units are described. A theoretical model to define the solubilizer’s velocity above the perforation holes, in the above-shelf space of the device and in the outloading gap, as well as the residence time of the dispersed phase at the stage (perforated shelf contact) of the device is presented. The results of experimental studies regarding the influence, made by the structural parameters of the perforated shelf contacts, on the distribution pattern of single-phase and gas-dispersed flows in the workspace of the device, on the intensity of interphase heat transfer are presented. The conditions to create active hydrodynamic operating modes of multistage gravitational shelf devices, which provide higher efficiency of heat-mass transfer processes, and with lower gas consumption and hydraulic resistance compared to typical fluidized bed devices, are proved. Peculiarities regarding the implementation of heat-mass transfer processes in multistage devices are described using heat treatment and drying processes as examples.

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Investigation of the kinetic laws affecting the organic suspension granulation in the fluidized bed

Cited by 10 publications

References 10 publications

Determining the main regularities in the process of mineral fertilizer granule encapsulation in the fluidized bed apparatus

Determining the main regularities in the process of mineral fertilizer granule encapsulation in the fluidized bed apparatus

Design of a shelf pneumatic classifier for separating a polydisperse mixture of granulated superphosphate

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

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