Gas-Solid Flow Behavior in a Pneumatic Conveying System for Drying Applications: Coarse Particles Feeding with a Venturi Device
Affiliation(s)
Department of Chemical Engineering, Federal University of São Carlos, São Carlos, Brazil.
Department of Chemical Engineering, Federal University of São Carlos, São Carlos, Brazil.
ABSTRACT
The feeding of coarse particles (>0.5 mm diameter) directly into a riser operating at positive pressure is important for drying and pre-heating applications. The presence of the feeding device can lead to heterogeneity of drying and heating, and is the main factor responsible for pressure loss in short conveying systems. However, there is a lack of information concerning the axial and radial distributions of coarse particles in this type of configuration, despite the recent advances when dealing with fine particles (FCC catalyst). The present work therefore investigates a vertical venturi feeder with the conveying system operating in dilute-phase regime with 1 mm spherical glass particles. Experimental assays revealed the behavior of the mass flow rate of solids in the system, and pressure measurements were made along the riser in order to evaluate the accuracy of simulations. Euler-Euler simulations provided close estimation of the experimental pressure drop and the pressure drop according to distance in the linear region. Simulation of the fluid dynamics in the riser showed that solids clusters were formed at low concentrations near the feeding device, reflecting heterogeneity in the solid phase volume fraction.
The feeding of coarse particles (>0.5 mm diameter) directly into a riser operating at positive pressure is important for drying and pre-heating applications. The presence of the feeding device can lead to heterogeneity of drying and heating, and is the main factor responsible for pressure loss in short conveying systems. However, there is a lack of information concerning the axial and radial distributions of coarse particles in this type of configuration, despite the recent advances when dealing with fine particles (FCC catalyst). The present work therefore investigates a vertical venturi feeder with the conveying system operating in dilute-phase regime with 1 mm spherical glass particles. Experimental assays revealed the behavior of the mass flow rate of solids in the system, and pressure measurements were made along the riser in order to evaluate the accuracy of simulations. Euler-Euler simulations provided close estimation of the experimental pressure drop and the pressure drop according to distance in the linear region. Simulation of the fluid dynamics in the riser showed that solids clusters were formed at low concentrations near the feeding device, reflecting heterogeneity in the solid phase volume fraction.
Cite this paper
Pádua, T. , Béttega, R. and Freire, J. (2015) Gas-Solid Flow Behavior in a Pneumatic Conveying System for Drying Applications: Coarse Particles Feeding with a Venturi Device. Advances in Chemical Engineering and Science, 5, 225-238. doi: 10.4236/aces.2015.53024.
Pádua, T. , Béttega, R. and Freire, J. (2015) Gas-Solid Flow Behavior in a Pneumatic Conveying System for Drying Applications: Coarse Particles Feeding with a Venturi Device. Advances in Chemical Engineering and Science, 5, 225-238. doi: 10.4236/aces.2015.53024.
References
[1] Hidayat, M. and Rasmuson, A. (2004) Numerical Assessment of Gas-Solid Flow in a U-Bend. Chem. Research in Engineering Design, 82, 332-343.
http://dx.doi.org/10.1205/026387604322870444 [2] Hidayat, M. and Rasmuson, A. (2007) Heat and Mass Transfer in U-Bend of a Pneumatic Conveying Dryer. Chemical Engineering Research and Design, 85, 307-319.
http://dx.doi.org/10.1205/cherd06162 [3] Rajan, K.S., Dhasandhan, K., Srivastava, S.N. and Pitchumani B. (2008) Studies on Gas-Solid Heat Transfer during Pneumatic Conveying. International Journal of Heat and Mass Transfer, 51, 2801-2813.
http://dx.doi.org/10.1016/j.ijheatmasstransfer.2007.09.042 [4] Sousa, R.C., Almeida, A.R.F., Ferreira, M.C. and Freire, J.T. (2010) Analysis of Fluid Dynamics and Thermal Behavior Using a Vertical Conveyor with a Spouted Bed Feeder. Drying Technology, 28, 1277-1287.
http://dx.doi.org/10.1080/07373937.2010.483031 [5] Fokeer, S., Kingman, S., Lowndes, I. and Reynolds, A. (2004) Characterisation of the Cross Sectional Particle Concentration Distribution in Horizontal Dilute Flow Conveying—A Review. Chemical Engineering and Processing, 43, 677-691.
http://dx.doi.org/10.1016/S0255-2701(03)00096-5 [6] Zhu, K.W., Rao, S.M., Wang, C.H. and Sundaresan, S. (2003) Electrical Capacitance Tomography Measurements on Vertical and Inclined Pneumatic Conveying of Granular Solids. Chemical Engineering Science, 58, 4225-4245.
http://dx.doi.org/10.1016/S0009-2509(03)00306-3 [7] Vashisth, S. and Grace, J.R. (2012) Simulation of Granular Transport of Geldart Type-A, -B, and -D Particles through a 90 Degrees Elbow. Industrial & Engineering Chemistry Research, 51, 2030-2047.
http://dx.doi.org/10.1021/ie200647e [8] Grbavcic, Z.B., Garic, R.V., Jovanovic, S.D. and Rozic, L.S. (1997) Hydrodynamic Modeling of Vertical Accelerating Gas-Solid Flow. Powder Technology, 92, 155-161.
http://dx.doi.org/10.1016/S0032-5910(97)03234-8 [9] Lopes, C.S., Pádua, T.F., Ferreira, M.C. and Freire, J.T. (2011) Influence of the Entrance Configuration on the Performance of a Non-Mechanical Solid Feeding Device for a Pneumatic Dryer. Drying Technology, 29, 1186-1194.
http://dx.doi.org/10.1080/07373937.2011.575495 [10] Rajan, K.S., Srivastava, S.N., Pitchumani, B. and Mohanty, B. (2006) Simulation of Gas-Solid Heat Transfer during Pneumatic Conveying: Use of Multiple Gas Inlets along the Duct. International Communications in Heat and Mass Transfer, 33, 1234-1242.
http://dx.doi.org/10.1016/j.icheatmasstransfer.2006.06.011 [11] Grace, J.R. and Taghipour, F. (2004) Verification and Validation of CFD Models and Dynamic Similarity for Fluidized Beds. Powder Technology, 139, 99-110.
http://dx.doi.org/10.1016/j.powtec.2003.10.006 [12] Du, B., Warsito, W. and Fan, L.S. (2004) ECT Studies of the Choking Phenomenon in a Gas-Solid Circulating Fluidized Bed. AIChE Journal, 50, 1386-1406.
http://dx.doi.org/10.1002/aic.10168 [13] Chan, C.W., Seville, J.P.K., Parker, D.J. and Baeyens, J. (2010) Particle Velocities and Their Residence Time Distribution in the Riser of a CFB. Powder Technology, 203, 187-197.
http://dx.doi.org/10.1016/j.powtec.2010.05.008 [14] Costa, I.A., Ferreira, M.D. and Freire, J.T. (2004) Analysis of Regime Transitions and Flow Instabilities in Vertical Conveying of Coarse Particles Using Different Solids Feeding Systems. The Canadian Journal of Chemical Engineering, 82, 48-59.
http://dx.doi.org/10.1002/cjce.5450820107 [15] Mills, D. (2004) Pneumatic Conveying Design Guide. Elsevier Butterworth-Heinemann, Oxford. [16] Béttega, R., Rosa, C.A., Corrêa, R.G. and Freire, J.T. (2009) Fluid Dynamic Study of a Semicylindrical Spouted Bed: Evaluation of the Shear Stress Effects in the Flat Wall Region Using Computational Fluid Dynamics. Industrial & Engineering Chemistry Research, 48, 11181-11188.
http://dx.doi.org/10.1021/ie900973x [17] Wen, C.Y. and Yu, Y.H. (1966) Mechanics of Fluidization. The Chemical Engineering Progress Symposium Series, 162, 100-111. [18] Gidaspow, D., Bezburuah, R. and Ding J. (1992) Hydrodynamics of Circulating Fluidized Beds, Kinetic Theory Approach. In: Potter, O.E. and Nicklin, D.J., Eds., Fluidization VII, Proceedings of the 7th Engineering Foundation Conference on Fluidization, Engineering Foundation, New York, 75-82. [19] Lun, C.K.K., Savage, S.B., Jeffrey, D.J. and Chepurniy, N. (1984) Kinetics Theories for Granular Flow: Inelastic Particles in Couette Flow and Slightly Inelastic Particles in a General Flowfield. Journal of Fluid Mechanics, 140, 223-256.
http://dx.doi.org/10.1017/S0022112084000586 [20] Wilde, de J., Van Engelandt, G., Heyndenickx, G.J. and Marin, G.B. (2005) Gas Solids Mixing in the Inlet Zone of a Dilute Circulating Fluidized Bed. Powder Technology, 151, 96-116.
http://dx.doi.org/10.1016/j.powtec.2004.11.037
[1] Hidayat, M. and Rasmuson, A. (2004) Numerical Assessment of Gas-Solid Flow in a U-Bend. Chem. Research in Engineering Design, 82, 332-343.
http://dx.doi.org/10.1205/026387604322870444 [2] Hidayat, M. and Rasmuson, A. (2007) Heat and Mass Transfer in U-Bend of a Pneumatic Conveying Dryer. Chemical Engineering Research and Design, 85, 307-319.
http://dx.doi.org/10.1205/cherd06162 [3] Rajan, K.S., Dhasandhan, K., Srivastava, S.N. and Pitchumani B. (2008) Studies on Gas-Solid Heat Transfer during Pneumatic Conveying. International Journal of Heat and Mass Transfer, 51, 2801-2813.
http://dx.doi.org/10.1016/j.ijheatmasstransfer.2007.09.042 [4] Sousa, R.C., Almeida, A.R.F., Ferreira, M.C. and Freire, J.T. (2010) Analysis of Fluid Dynamics and Thermal Behavior Using a Vertical Conveyor with a Spouted Bed Feeder. Drying Technology, 28, 1277-1287.
http://dx.doi.org/10.1080/07373937.2010.483031 [5] Fokeer, S., Kingman, S., Lowndes, I. and Reynolds, A. (2004) Characterisation of the Cross Sectional Particle Concentration Distribution in Horizontal Dilute Flow Conveying—A Review. Chemical Engineering and Processing, 43, 677-691.
http://dx.doi.org/10.1016/S0255-2701(03)00096-5 [6] Zhu, K.W., Rao, S.M., Wang, C.H. and Sundaresan, S. (2003) Electrical Capacitance Tomography Measurements on Vertical and Inclined Pneumatic Conveying of Granular Solids. Chemical Engineering Science, 58, 4225-4245.
http://dx.doi.org/10.1016/S0009-2509(03)00306-3 [7] Vashisth, S. and Grace, J.R. (2012) Simulation of Granular Transport of Geldart Type-A, -B, and -D Particles through a 90 Degrees Elbow. Industrial & Engineering Chemistry Research, 51, 2030-2047.
http://dx.doi.org/10.1021/ie200647e [8] Grbavcic, Z.B., Garic, R.V., Jovanovic, S.D. and Rozic, L.S. (1997) Hydrodynamic Modeling of Vertical Accelerating Gas-Solid Flow. Powder Technology, 92, 155-161.
http://dx.doi.org/10.1016/S0032-5910(97)03234-8 [9] Lopes, C.S., Pádua, T.F., Ferreira, M.C. and Freire, J.T. (2011) Influence of the Entrance Configuration on the Performance of a Non-Mechanical Solid Feeding Device for a Pneumatic Dryer. Drying Technology, 29, 1186-1194.
http://dx.doi.org/10.1080/07373937.2011.575495 [10] Rajan, K.S., Srivastava, S.N., Pitchumani, B. and Mohanty, B. (2006) Simulation of Gas-Solid Heat Transfer during Pneumatic Conveying: Use of Multiple Gas Inlets along the Duct. International Communications in Heat and Mass Transfer, 33, 1234-1242.
http://dx.doi.org/10.1016/j.icheatmasstransfer.2006.06.011 [11] Grace, J.R. and Taghipour, F. (2004) Verification and Validation of CFD Models and Dynamic Similarity for Fluidized Beds. Powder Technology, 139, 99-110.
http://dx.doi.org/10.1016/j.powtec.2003.10.006 [12] Du, B., Warsito, W. and Fan, L.S. (2004) ECT Studies of the Choking Phenomenon in a Gas-Solid Circulating Fluidized Bed. AIChE Journal, 50, 1386-1406.
http://dx.doi.org/10.1002/aic.10168 [13] Chan, C.W., Seville, J.P.K., Parker, D.J. and Baeyens, J. (2010) Particle Velocities and Their Residence Time Distribution in the Riser of a CFB. Powder Technology, 203, 187-197.
http://dx.doi.org/10.1016/j.powtec.2010.05.008 [14] Costa, I.A., Ferreira, M.D. and Freire, J.T. (2004) Analysis of Regime Transitions and Flow Instabilities in Vertical Conveying of Coarse Particles Using Different Solids Feeding Systems. The Canadian Journal of Chemical Engineering, 82, 48-59.
http://dx.doi.org/10.1002/cjce.5450820107 [15] Mills, D. (2004) Pneumatic Conveying Design Guide. Elsevier Butterworth-Heinemann, Oxford. [16] Béttega, R., Rosa, C.A., Corrêa, R.G. and Freire, J.T. (2009) Fluid Dynamic Study of a Semicylindrical Spouted Bed: Evaluation of the Shear Stress Effects in the Flat Wall Region Using Computational Fluid Dynamics. Industrial & Engineering Chemistry Research, 48, 11181-11188.
http://dx.doi.org/10.1021/ie900973x [17] Wen, C.Y. and Yu, Y.H. (1966) Mechanics of Fluidization. The Chemical Engineering Progress Symposium Series, 162, 100-111. [18] Gidaspow, D., Bezburuah, R. and Ding J. (1992) Hydrodynamics of Circulating Fluidized Beds, Kinetic Theory Approach. In: Potter, O.E. and Nicklin, D.J., Eds., Fluidization VII, Proceedings of the 7th Engineering Foundation Conference on Fluidization, Engineering Foundation, New York, 75-82. [19] Lun, C.K.K., Savage, S.B., Jeffrey, D.J. and Chepurniy, N. (1984) Kinetics Theories for Granular Flow: Inelastic Particles in Couette Flow and Slightly Inelastic Particles in a General Flowfield. Journal of Fluid Mechanics, 140, 223-256.
http://dx.doi.org/10.1017/S0022112084000586 [20] Wilde, de J., Van Engelandt, G., Heyndenickx, G.J. and Marin, G.B. (2005) Gas Solids Mixing in the Inlet Zone of a Dilute Circulating Fluidized Bed. Powder Technology, 151, 96-116.
http://dx.doi.org/10.1016/j.powtec.2004.11.037