A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed

M.S. van Buijtenen, N.G. Deen, Stefan Heinrich, Sergiy Antonyuk, J.A.M. Kuipers

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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    Abstract

    Spout fluidized beds find widespread application in the process industry in granulation processes, in which efficient contacting between large particles, droplets and gas is of paramount importance. However, detailed understanding of the complex behavior of these systems is lacking. In this paper we study the effect of the inter-particle interaction on the bed dynamics, by investigating the bed height, pressure drop and vertical particle velocity as function of the variable
    restitution coefficient, which varies in time and space as function of the moisture content due to the particle-droplet interaction. This is done computationally, by using the extended discrete element model (DEM) which describes the dynamics of the continuous gas-phase and the discrete particles and droplets. The objective of this work is to gain insight in the effect of the variable restitution coefficient on the flow behavior of spout fluidized beds at different flow
    regimes using DEM. The three flow regimes comprise the intermediate / spout-fluidization regime (B1), spouting-withaeration regime (B2) and the jet-in-fluidized-bed regime (B3). The simulation results with variable restitution
    coefficients were compared to simulations with constant restitution coefficients reported by Van Buijtenen et al. (2007). The trend of increasing average bed height with decreasing restitution coefficient is also valid for the variable restitution coefficient. However, the average bed height is larger for the variable restitution coefficient for all flow regimes. This is also observed for the pressure drop, showing a lower value compared to the constant restitution coefficient.
    These results suggest a significant influence of the variable restitution coefficient on the bed dynamics, since the variable restitution coefficient provides regions in the bed with particles having different collision properties. The presence of these distinctive regions causes different behavior of the
    bed dynamics, which is also shown in the time-averaged vertical particle velocity. The velocity in the spout region for the variable restitution coefficient is lower than for the constant restitution coefficient for case B1 and B2. However,
    for case B3 these regions are less pronounced, due to the larger mixing capacity caused by the larger interaction between the spout channel and the bubbles in the annulus region. As a result, the particle velocity for the variable restitution coefficient complies with the particle velocity for the constant restitution coefficient.
    These findings reveal the significant impact of the influence of the variable restitution coefficient on the dynamics of the bed, which is clearly different compared to the constant restitution coefficient. This is due to the presence of
    distinctive regions with different restitution coefficient, which can only be simulated when the dependency of the moisture content on the restitution coefficient is accounted for. Currently, only the wetting process on the particles has been simulated without evaporation and crystallization of the deposited granulate solution, which are phenomena that are very important in the granulation process. It is therefore desirable to further improve the discrete element model, by solving mass and energy balances for the particles and the gas phase.
    Original languageEnglish
    Title of host publication6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008
    Place of PublicationTrondheim, Norway
    Number of pages13
    Publication statusPublished - 2008
    Event6th International Conference on CFD in the Oil & Gas, Metallurgical and Process Industries 2008 - Trondheim, Norway
    Duration: 10 Jun 200812 Jun 2008

    Conference

    Conference6th International Conference on CFD in the Oil & Gas, Metallurgical and Process Industries 2008
    CountryNorway
    CityTrondheim
    Period10/06/0812/06/08
    Other10-12 June 2008

    Fingerprint

    moisture
    droplet
    pressure drop
    moisture content
    particle
    gas
    fluidization
    wetting
    energy balance
    simulation
    bubble
    mass balance
    crystallization
    evaporation
    collision
    industry

    Keywords

    • IR-68588
    • METIS-254301

    Cite this

    van Buijtenen, M. S., Deen, N. G., Heinrich, S., Antonyuk, S., & Kuipers, J. A. M. (2008). A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed. In 6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008 Trondheim, Norway.
    van Buijtenen, M.S. ; Deen, N.G. ; Heinrich, Stefan ; Antonyuk, Sergiy ; Kuipers, J.A.M. / A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed. 6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008. Trondheim, Norway, 2008.
    @inproceedings{d3d87cd703f64924991640f6320becbe,
    title = "A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed",
    abstract = "Spout fluidized beds find widespread application in the process industry in granulation processes, in which efficient contacting between large particles, droplets and gas is of paramount importance. However, detailed understanding of the complex behavior of these systems is lacking. In this paper we study the effect of the inter-particle interaction on the bed dynamics, by investigating the bed height, pressure drop and vertical particle velocity as function of the variablerestitution coefficient, which varies in time and space as function of the moisture content due to the particle-droplet interaction. This is done computationally, by using the extended discrete element model (DEM) which describes the dynamics of the continuous gas-phase and the discrete particles and droplets. The objective of this work is to gain insight in the effect of the variable restitution coefficient on the flow behavior of spout fluidized beds at different flowregimes using DEM. The three flow regimes comprise the intermediate / spout-fluidization regime (B1), spouting-withaeration regime (B2) and the jet-in-fluidized-bed regime (B3). The simulation results with variable restitutioncoefficients were compared to simulations with constant restitution coefficients reported by Van Buijtenen et al. (2007). The trend of increasing average bed height with decreasing restitution coefficient is also valid for the variable restitution coefficient. However, the average bed height is larger for the variable restitution coefficient for all flow regimes. This is also observed for the pressure drop, showing a lower value compared to the constant restitution coefficient.These results suggest a significant influence of the variable restitution coefficient on the bed dynamics, since the variable restitution coefficient provides regions in the bed with particles having different collision properties. The presence of these distinctive regions causes different behavior of thebed dynamics, which is also shown in the time-averaged vertical particle velocity. The velocity in the spout region for the variable restitution coefficient is lower than for the constant restitution coefficient for case B1 and B2. However,for case B3 these regions are less pronounced, due to the larger mixing capacity caused by the larger interaction between the spout channel and the bubbles in the annulus region. As a result, the particle velocity for the variable restitution coefficient complies with the particle velocity for the constant restitution coefficient.These findings reveal the significant impact of the influence of the variable restitution coefficient on the dynamics of the bed, which is clearly different compared to the constant restitution coefficient. This is due to the presence ofdistinctive regions with different restitution coefficient, which can only be simulated when the dependency of the moisture content on the restitution coefficient is accounted for. Currently, only the wetting process on the particles has been simulated without evaporation and crystallization of the deposited granulate solution, which are phenomena that are very important in the granulation process. It is therefore desirable to further improve the discrete element model, by solving mass and energy balances for the particles and the gas phase.",
    keywords = "IR-68588, METIS-254301",
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    year = "2008",
    language = "English",
    booktitle = "6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008",

    }

    van Buijtenen, MS, Deen, NG, Heinrich, S, Antonyuk, S & Kuipers, JAM 2008, A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed. in 6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008. Trondheim, Norway, 6th International Conference on CFD in the Oil & Gas, Metallurgical and Process Industries 2008, Trondheim, Norway, 10/06/08.

    A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed. / van Buijtenen, M.S.; Deen, N.G.; Heinrich, Stefan; Antonyuk, Sergiy; Kuipers, J.A.M.

    6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008. Trondheim, Norway, 2008.

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    TY - GEN

    T1 - A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed

    AU - van Buijtenen, M.S.

    AU - Deen, N.G.

    AU - Heinrich, Stefan

    AU - Antonyuk, Sergiy

    AU - Kuipers, J.A.M.

    PY - 2008

    Y1 - 2008

    N2 - Spout fluidized beds find widespread application in the process industry in granulation processes, in which efficient contacting between large particles, droplets and gas is of paramount importance. However, detailed understanding of the complex behavior of these systems is lacking. In this paper we study the effect of the inter-particle interaction on the bed dynamics, by investigating the bed height, pressure drop and vertical particle velocity as function of the variablerestitution coefficient, which varies in time and space as function of the moisture content due to the particle-droplet interaction. This is done computationally, by using the extended discrete element model (DEM) which describes the dynamics of the continuous gas-phase and the discrete particles and droplets. The objective of this work is to gain insight in the effect of the variable restitution coefficient on the flow behavior of spout fluidized beds at different flowregimes using DEM. The three flow regimes comprise the intermediate / spout-fluidization regime (B1), spouting-withaeration regime (B2) and the jet-in-fluidized-bed regime (B3). The simulation results with variable restitutioncoefficients were compared to simulations with constant restitution coefficients reported by Van Buijtenen et al. (2007). The trend of increasing average bed height with decreasing restitution coefficient is also valid for the variable restitution coefficient. However, the average bed height is larger for the variable restitution coefficient for all flow regimes. This is also observed for the pressure drop, showing a lower value compared to the constant restitution coefficient.These results suggest a significant influence of the variable restitution coefficient on the bed dynamics, since the variable restitution coefficient provides regions in the bed with particles having different collision properties. The presence of these distinctive regions causes different behavior of thebed dynamics, which is also shown in the time-averaged vertical particle velocity. The velocity in the spout region for the variable restitution coefficient is lower than for the constant restitution coefficient for case B1 and B2. However,for case B3 these regions are less pronounced, due to the larger mixing capacity caused by the larger interaction between the spout channel and the bubbles in the annulus region. As a result, the particle velocity for the variable restitution coefficient complies with the particle velocity for the constant restitution coefficient.These findings reveal the significant impact of the influence of the variable restitution coefficient on the dynamics of the bed, which is clearly different compared to the constant restitution coefficient. This is due to the presence ofdistinctive regions with different restitution coefficient, which can only be simulated when the dependency of the moisture content on the restitution coefficient is accounted for. Currently, only the wetting process on the particles has been simulated without evaporation and crystallization of the deposited granulate solution, which are phenomena that are very important in the granulation process. It is therefore desirable to further improve the discrete element model, by solving mass and energy balances for the particles and the gas phase.

    AB - Spout fluidized beds find widespread application in the process industry in granulation processes, in which efficient contacting between large particles, droplets and gas is of paramount importance. However, detailed understanding of the complex behavior of these systems is lacking. In this paper we study the effect of the inter-particle interaction on the bed dynamics, by investigating the bed height, pressure drop and vertical particle velocity as function of the variablerestitution coefficient, which varies in time and space as function of the moisture content due to the particle-droplet interaction. This is done computationally, by using the extended discrete element model (DEM) which describes the dynamics of the continuous gas-phase and the discrete particles and droplets. The objective of this work is to gain insight in the effect of the variable restitution coefficient on the flow behavior of spout fluidized beds at different flowregimes using DEM. The three flow regimes comprise the intermediate / spout-fluidization regime (B1), spouting-withaeration regime (B2) and the jet-in-fluidized-bed regime (B3). The simulation results with variable restitutioncoefficients were compared to simulations with constant restitution coefficients reported by Van Buijtenen et al. (2007). The trend of increasing average bed height with decreasing restitution coefficient is also valid for the variable restitution coefficient. However, the average bed height is larger for the variable restitution coefficient for all flow regimes. This is also observed for the pressure drop, showing a lower value compared to the constant restitution coefficient.These results suggest a significant influence of the variable restitution coefficient on the bed dynamics, since the variable restitution coefficient provides regions in the bed with particles having different collision properties. The presence of these distinctive regions causes different behavior of thebed dynamics, which is also shown in the time-averaged vertical particle velocity. The velocity in the spout region for the variable restitution coefficient is lower than for the constant restitution coefficient for case B1 and B2. However,for case B3 these regions are less pronounced, due to the larger mixing capacity caused by the larger interaction between the spout channel and the bubbles in the annulus region. As a result, the particle velocity for the variable restitution coefficient complies with the particle velocity for the constant restitution coefficient.These findings reveal the significant impact of the influence of the variable restitution coefficient on the dynamics of the bed, which is clearly different compared to the constant restitution coefficient. This is due to the presence ofdistinctive regions with different restitution coefficient, which can only be simulated when the dependency of the moisture content on the restitution coefficient is accounted for. Currently, only the wetting process on the particles has been simulated without evaporation and crystallization of the deposited granulate solution, which are phenomena that are very important in the granulation process. It is therefore desirable to further improve the discrete element model, by solving mass and energy balances for the particles and the gas phase.

    KW - IR-68588

    KW - METIS-254301

    M3 - Conference contribution

    BT - 6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008

    CY - Trondheim, Norway

    ER -

    van Buijtenen MS, Deen NG, Heinrich S, Antonyuk S, Kuipers JAM. A discrete element study of moisture dependent particle-particle interaction during granulation in a spout fluidized bed. In 6th international conference on computational fluid dynamics in the oil & gas, metallurgical and process industries, Trondheim, Norway, 10 - 12 June 2008. Trondheim, Norway. 2008