Porous Particles Drying in a Vertical Upward Pneumatic Conveying Dryer
A steady two-phase flow model has been developed to simulate the drying process of porous particle in a pneumatic conveying dryer. The model takes into account the momentum, heat and mass transfer between the continuous phase and the dispersed phase. A single particle model was employed to calculate the evaporation rate. In this model the pore structure is simplified to allow the dominant evaporation mechanism to be readily identified at all points within the duct. The predominant mechanism at any time depends upon the pressure, temperature and the diameter of pore from which evaporating is occurring. The model was validated against experimental studies of pneumatic transport at low and high speeds as well as pneumatic drying. The effects of operating conditions on the dryer parameters are studied numerically. The present results show that the drying rate is enhanced as the inlet gas temperature and the gas flow rate increase and as the solid mass flow rate deceases. The present results also demonstrate the necessity of measuring the inlet gas velocity or the solid concentration in any experimental analysis.
[1] Baeyens J., Gauwbergen D. V. and Vinckier I., 1995, "Pneumatic
Drying: the Use of Large-Scale Data in a Design Procedure", Powder
Tech., Vol. 83, pp. 139-148.
[2] Borde I. and Levy A., 2006, "Pneumatic and Flash Drying", in
Handbook of Industrial Drying, 3rd Ed., (Mujumdar A. S. Ed.), CRC
Press, New York.
[3] Moyers C. G. and Baldwin G. W., 1997, "Psychrometry, Evaporative
Cooling, and Solids Drying", in Perry-s Chemical Engineers- Handbook,
7th Ed. (Eds. Robert H. Perry R. H., Green D. W. and Maloney J. O.),
McGraw-Hill, Inc.
[4] Thorpe G.R., Wint A. and Coggan G.C., 1973, "The Mathematical
Modelling of Industrial Pneumatic Driers", Transactions of the
Institution of Chemical Engineers, Vol. 51, pp. 339-348.
[5] Kemp I. C., Bahu R. E. and Pasley H. S., 1994, "Model Development
and Experimental Studies of Vertical Pneumatic Conveying Dryers",
Drying Tech., Vol. 12, pp. 1323-1340.
[6] Kemp I. C and Oakley D. E., 1997, "Simulation and Scale-up of
Pneumatic Conveying and Cascading Rotary Dryers", Drying Tech.,
Vol. 15, pp. 1699-1710.
[7] Kemp I. C., Oakley D. E. and Bahu R. E., 1991, "Computational Fluid
Dynamics Modelling of Vertical Pneumatic Conveying Dryers", Powder
Tech., Vol. 65, pp. 477-484.
[8] Radford R. D., 1997, "A Model of Particulate Drying in Pneumatic
Conveying Systems", Powder Tech., Vol. 93, pp. 109-126.
[9] Levy A. and Borde I., 1999, "Steady State One Dimensional Flow Model
for a Pneumatic Dryer", Chem. Eng. Processing, Vol. 38, pp. 121-130.
[10] Skuratovsky I., Levy A. and Borde I., 2003, "Two-Fluid Two-
Dimensional Model for Pneumatic Drying", Drying Tech., Vol. 21, pp.
1645-1668.
[11] Skuratovsky I., Levy A. and Borde I., 2005, "Two-Dimensional
Numerical Simulations of the Pneumatic Drying in Vertical pipes",
Chem. Eng. Processing, Vol. 44, pp. 187-192.
[12] Pelegrina A. H. and Crapiste G. H., 2001, "Modelling the Pneumatic
Drying of Food Particles", J. Food Eng., Vol. 48, pp. 301-310.
[13] Narimatsu C. P., Ferreira M. C. and Feire J. T., 2007, "Drying of Coarse
Particles in a Vertical Pneumatic Conveyor", Drying Tech., Vol. 25, pp.
291-302.
[14] Fyhr C. and Rasmuson A., 1997, "Mathematical Model of Pneumatic
Conveying Dryer", AICHE Journal, Vol. 43, pp. 2889-2902.
[15] Fyhr C. and Rasmuson A., 1997, "Steam Drying of Wood Ships in
Pneumatic Conveying Dryers", Drying Tech., Vol. 15, pp. 1775-1785.
[16] Alvarez P. I., Vega R. and Blasco R., 2005, "Cocurrent Downflow
Fluidized Bed Dryer: Experimental Equipment and Modeling", Drying
Tech., Vol. 23, pp. 1435-1449.
[17] NamKung W. and Cho M., 2004, "Pneumatic Drying of Iron Ore
particles in a Vertical tube", Drying Tech., Vol. 22, pp. 877-891.
[18] Kaensup W., Kulwong S. and Wongwises S., 2006, "A Small-Scale
Pneumatic Conveying Dryer of Rough Rice", Drying Tech., Vol. 24, pp.
105-113.
[19] Kaensup W., Kulwong S. and Wongwises S., 2006, "Comparison of
Drying Kinetics of Paddy Using a Pneumatic Dryer with and without a
Cyclone", Drying Tech., Vol. 24, pp. 1039-1045.
[20] Hamed M. H., 2005," Choked Gas-Solid Two-Phase Flow in Pipes", J.
Eng. Applied Science, Faculty of Engineering, Cairo University, Vol.
52, pp. 961-980.
[21] Kladas, D. D. and Deorgiou, D. P., 1993, "A Relative Examination of
CD-Re Relationships used in Particle Trajectory Calculations", Trans.
of ASME, J. of Fluids Engineering, Vol. 115, pp. 162-165.
[22] Han, T., A. Levy, and Y. Peng, 2000, "Model for Dilute Gas-Particle
Flow in Constant-Area Lance with Heating and Friction ", Powder
Technology, Vol. 112, pp. 283-288.
[23] Debrand S., 1974, "Heat Transfer during a Flash Drying Process", Ind.
Eng. Chem., Process Des. Develop., Vol. 13, pp. 396-404.
[24] Welty J. R., Wicks G. E. and Wilson R. E., 1984, "Fundamentals of
Momentum, Heat, and Mass Transfer", 3rd Ed., John Wiley & Sons,
New York.
[25] Reynolds W. C., 1979, "Thermodynamic Properties in SI: Graphs,
Tables and Computational Equations for Forty Substances", Published
by the Department of Mechanical Engineering, Stanford University,
Stanford CA 94305.
[26] Crowe C., Sommerfeld M. and Tsuji Y., 1998, "Multiphase Flow with
Droplets and Particles", CRC Press, Florida, USA.
[27] Hariu O. H. and Molstad M. C., 194, "Pressure Drop in Vertical Tubes
in Transport of Solids by Gases", Industrial and Engineering Chemistry,
Vol. 41, pp. 1148-1160.
[28] Arastoopour H. and Gidaspow D., 1979, "Vertical Pneumatic Conveying
Using Four Hydrodynamic Models", Ind. Eng. Chem. Fundam., Vol. 18,
pp. 123-130.
[29] Mobbs F. R., Bowers H. M., D. M. Riches D. M., and Cole B. N., 1969-
70, "Influence of Particle Size Distribution on the high-Speed flow of
Gas-Solid Suspensions in a Pipe", Proc Instn Mech Engrs, Vol. 184, Pt
3C, paper 9.
[30] Bunyawanichakul P., Walker G. J., Sargison J. E. and Doe P. E., 2007,
"Modelling and Simulation of Paddy Grain (Rice) Drying in a simple
Pneumatic Dryer", Biosystems Eng., Vol. 96, pp. 335-344.
[31] Saravanan B., Balsubramaniam N. and Srinivasakannan C., 2007,
"Drying Kinetics in a Vertical Gas-Solid System", Chem. Eng. Tech.,
Vol. 30, pp. 176-183.
[1] Baeyens J., Gauwbergen D. V. and Vinckier I., 1995, "Pneumatic
Drying: the Use of Large-Scale Data in a Design Procedure", Powder
Tech., Vol. 83, pp. 139-148.
[2] Borde I. and Levy A., 2006, "Pneumatic and Flash Drying", in
Handbook of Industrial Drying, 3rd Ed., (Mujumdar A. S. Ed.), CRC
Press, New York.
[3] Moyers C. G. and Baldwin G. W., 1997, "Psychrometry, Evaporative
Cooling, and Solids Drying", in Perry-s Chemical Engineers- Handbook,
7th Ed. (Eds. Robert H. Perry R. H., Green D. W. and Maloney J. O.),
McGraw-Hill, Inc.
[4] Thorpe G.R., Wint A. and Coggan G.C., 1973, "The Mathematical
Modelling of Industrial Pneumatic Driers", Transactions of the
Institution of Chemical Engineers, Vol. 51, pp. 339-348.
[5] Kemp I. C., Bahu R. E. and Pasley H. S., 1994, "Model Development
and Experimental Studies of Vertical Pneumatic Conveying Dryers",
Drying Tech., Vol. 12, pp. 1323-1340.
[6] Kemp I. C and Oakley D. E., 1997, "Simulation and Scale-up of
Pneumatic Conveying and Cascading Rotary Dryers", Drying Tech.,
Vol. 15, pp. 1699-1710.
[7] Kemp I. C., Oakley D. E. and Bahu R. E., 1991, "Computational Fluid
Dynamics Modelling of Vertical Pneumatic Conveying Dryers", Powder
Tech., Vol. 65, pp. 477-484.
[8] Radford R. D., 1997, "A Model of Particulate Drying in Pneumatic
Conveying Systems", Powder Tech., Vol. 93, pp. 109-126.
[9] Levy A. and Borde I., 1999, "Steady State One Dimensional Flow Model
for a Pneumatic Dryer", Chem. Eng. Processing, Vol. 38, pp. 121-130.
[10] Skuratovsky I., Levy A. and Borde I., 2003, "Two-Fluid Two-
Dimensional Model for Pneumatic Drying", Drying Tech., Vol. 21, pp.
1645-1668.
[11] Skuratovsky I., Levy A. and Borde I., 2005, "Two-Dimensional
Numerical Simulations of the Pneumatic Drying in Vertical pipes",
Chem. Eng. Processing, Vol. 44, pp. 187-192.
[12] Pelegrina A. H. and Crapiste G. H., 2001, "Modelling the Pneumatic
Drying of Food Particles", J. Food Eng., Vol. 48, pp. 301-310.
[13] Narimatsu C. P., Ferreira M. C. and Feire J. T., 2007, "Drying of Coarse
Particles in a Vertical Pneumatic Conveyor", Drying Tech., Vol. 25, pp.
291-302.
[14] Fyhr C. and Rasmuson A., 1997, "Mathematical Model of Pneumatic
Conveying Dryer", AICHE Journal, Vol. 43, pp. 2889-2902.
[15] Fyhr C. and Rasmuson A., 1997, "Steam Drying of Wood Ships in
Pneumatic Conveying Dryers", Drying Tech., Vol. 15, pp. 1775-1785.
[16] Alvarez P. I., Vega R. and Blasco R., 2005, "Cocurrent Downflow
Fluidized Bed Dryer: Experimental Equipment and Modeling", Drying
Tech., Vol. 23, pp. 1435-1449.
[17] NamKung W. and Cho M., 2004, "Pneumatic Drying of Iron Ore
particles in a Vertical tube", Drying Tech., Vol. 22, pp. 877-891.
[18] Kaensup W., Kulwong S. and Wongwises S., 2006, "A Small-Scale
Pneumatic Conveying Dryer of Rough Rice", Drying Tech., Vol. 24, pp.
105-113.
[19] Kaensup W., Kulwong S. and Wongwises S., 2006, "Comparison of
Drying Kinetics of Paddy Using a Pneumatic Dryer with and without a
Cyclone", Drying Tech., Vol. 24, pp. 1039-1045.
[20] Hamed M. H., 2005," Choked Gas-Solid Two-Phase Flow in Pipes", J.
Eng. Applied Science, Faculty of Engineering, Cairo University, Vol.
52, pp. 961-980.
[21] Kladas, D. D. and Deorgiou, D. P., 1993, "A Relative Examination of
CD-Re Relationships used in Particle Trajectory Calculations", Trans.
of ASME, J. of Fluids Engineering, Vol. 115, pp. 162-165.
[22] Han, T., A. Levy, and Y. Peng, 2000, "Model for Dilute Gas-Particle
Flow in Constant-Area Lance with Heating and Friction ", Powder
Technology, Vol. 112, pp. 283-288.
[23] Debrand S., 1974, "Heat Transfer during a Flash Drying Process", Ind.
Eng. Chem., Process Des. Develop., Vol. 13, pp. 396-404.
[24] Welty J. R., Wicks G. E. and Wilson R. E., 1984, "Fundamentals of
Momentum, Heat, and Mass Transfer", 3rd Ed., John Wiley & Sons,
New York.
[25] Reynolds W. C., 1979, "Thermodynamic Properties in SI: Graphs,
Tables and Computational Equations for Forty Substances", Published
by the Department of Mechanical Engineering, Stanford University,
Stanford CA 94305.
[26] Crowe C., Sommerfeld M. and Tsuji Y., 1998, "Multiphase Flow with
Droplets and Particles", CRC Press, Florida, USA.
[27] Hariu O. H. and Molstad M. C., 194, "Pressure Drop in Vertical Tubes
in Transport of Solids by Gases", Industrial and Engineering Chemistry,
Vol. 41, pp. 1148-1160.
[28] Arastoopour H. and Gidaspow D., 1979, "Vertical Pneumatic Conveying
Using Four Hydrodynamic Models", Ind. Eng. Chem. Fundam., Vol. 18,
pp. 123-130.
[29] Mobbs F. R., Bowers H. M., D. M. Riches D. M., and Cole B. N., 1969-
70, "Influence of Particle Size Distribution on the high-Speed flow of
Gas-Solid Suspensions in a Pipe", Proc Instn Mech Engrs, Vol. 184, Pt
3C, paper 9.
[30] Bunyawanichakul P., Walker G. J., Sargison J. E. and Doe P. E., 2007,
"Modelling and Simulation of Paddy Grain (Rice) Drying in a simple
Pneumatic Dryer", Biosystems Eng., Vol. 96, pp. 335-344.
[31] Saravanan B., Balsubramaniam N. and Srinivasakannan C., 2007,
"Drying Kinetics in a Vertical Gas-Solid System", Chem. Eng. Tech.,
Vol. 30, pp. 176-183.
@article{"International Journal of Engineering, Mathematical and Physical Sciences:55398", author = "Samy M. El-Behery and W. A. El-Askary and K. A. Ibrahim and Mofreh H. Hamed", title = "Porous Particles Drying in a Vertical Upward Pneumatic Conveying Dryer", abstract = "A steady two-phase flow model has been developed to simulate the drying process of porous particle in a pneumatic conveying dryer. The model takes into account the momentum, heat and mass transfer between the continuous phase and the dispersed phase. A single particle model was employed to calculate the evaporation rate. In this model the pore structure is simplified to allow the dominant evaporation mechanism to be readily identified at all points within the duct. The predominant mechanism at any time depends upon the pressure, temperature and the diameter of pore from which evaporating is occurring. The model was validated against experimental studies of pneumatic transport at low and high speeds as well as pneumatic drying. The effects of operating conditions on the dryer parameters are studied numerically. The present results show that the drying rate is enhanced as the inlet gas temperature and the gas flow rate increase and as the solid mass flow rate deceases. The present results also demonstrate the necessity of measuring the inlet gas velocity or the solid concentration in any experimental analysis.
", keywords = "Two-phase, gas-solid, pneumatic drying, pneumatic
conveying, heat and mass transfer", volume = "3", number = "5", pages = "306-16", }
