Particles' degradation and dynamics in conveying systems

Abstract The attrition process of particles in conveying systems is a common problem in many industrial applications. The current study adopts a new approach to modeling particle breakage by implementing one-dimensional breakage algorithm (ODBA) in a one-dimensional flow model (Uzi et al., 2016). This method is used for the first time in two-way coupling, i.e. when the breakage affects the flow dynamics and vice versa. The one-dimensional flow model uses conventional balances of mass, momentum and energy. Moreover, the ODBA exploits empirical correlations for particle characteristics (i.e. breakage, equivalence and fatigue functions), and dynamic behavior (i.e. impact velocity and frequency) obtained from a coupled 3D CFD and Discrete Element Method (DEM) simulations. Both the dynamics of the particles and the attrition of the particles were validated using the proposed approach. A dilute pneumatic conveying system was considered, which comprises of 1 in. pipe and 5 straight sections and 4 bends (R/D = 1) with a total length of 14.5 m. CFD-DEM results served as the basis for the velocity validation, satisfying a good agreement along the conveying line. In this system, the attrition of Potash particles was simulated and compared with the experimental measurements of Kalman et al. (2004), showing an excellent agreement. This comparison consists of inlet gas superficial velocity of 40 m/s and is comprised of ten conveying cycles in order to emphasize the fatigue phenomena. The investigated case was also analyzed to provide the dynamic parameters of the two-phase flow with regard to the coupling with the breakage algorithm. It was well established that the flow parameters are sensitive to particle size. In the pressure variation, it was prominent that larger particles resolve a larger pressure drop, while the differences between the cycles in the velocity were more extensive. These differences were caused by the changes in particle size distribution and actualized due to the two-way coupling approach.

[1]  Haim Kalman,et al.  A novel particle attrition model for conveying systems , 2016 .

[2]  Michael J. Hounslow,et al.  Particle fragmentation in dilute phase pneumatic conveying , 2002 .

[3]  G. Ma,et al.  A hybrid approach for modeling of breakable granular materials using combined finite-discrete element method , 2016 .

[4]  Haim Kalman,et al.  DEM simulation of particle attrition in dilute-phase pneumatic conveying , 2011 .

[5]  K. A. Aarseth.  Attrition of Feed Pellets during Pneumatic Conveying: the Influence of Velocity and Bend Radius , 2004 .

[6]  Haim Kalman,et al.  Selection and breakage functions of particles under impact loads , 2012 .

[7]  Haim Kalman,et al.  Strength distribution of particles under compression , 2011 .

[8]  Csaba Sinka,et al.  Modeling and measurement of granule attrition during pneumatic conveying in a laboratory scale system , 2008 .

[9]  Haim Kalman,et al.  Impact velocity and compression force relationship — Equivalence function , 2013 .

[10]  Ronald W. Breault,et al.  High-velocity fluidized-bed hydrodynamic modeling. 1. Fundamental studies of pressure drop , 1989 .

[11]  Pierre Chapelle,et al.  Computational model for prediction of particle degradation during dilute-phase pneumatic conveying: the use of a laboratory-scale degradation tester for the determination of degradation propensity , 2004 .

[12]  W. Zhou,et al.  Numerical and experimental verification of a damping model used in DEM , 2016 .

[13]  Haim Kalman,et al.  DEM simulation for attrition of salt during dilute-phase pneumatic conveying , 2003 .

[14]  Richard A Williams,et al.  Solids Flow Imaging and Attrition Studies in a Pneumatic Conveyor , 1995 .

[15]  Haim Kalman,et al.  A model for particle fatigue due to impact loads , 2013 .

[16]  T. Taylor,et al.  Specific energy consumption and particle attrition in pneumatic conveying , 1998 .

[17]  Jennifer S. Curtis,et al.  Discrete Element Method Simulations for Complex Granular Flows , 2015 .

[18]  Wolfgang Peukert,et al.  Attrition of Bulk Solids in Pneumatic Conveying: Mechanisms and Material Properties , 2002 .

[19]  B. K. Mishra,et al.  A novel and direct approach for modeling and simulation of impact grinding , 2015 .

[20]  Haim Kalman,et al.  Theoretical and experimental study of multi-impact breakage of particles , 2006 .

[21]  Pierre Chapelle,et al.  Numerical predictions of particle degradation in industrial-scale pneumatic conveyors , 2004 .

[22]  Haim Kalman,et al.  Fragments spawning and interaction models for DEM breakage simulation , 2011 .

[23]  Haim Kalman,et al.  A new method to implement comminution functions into DEM simulation of a size reduction system due to particle-wall collisions , 2009 .

[24]  Haim Kalman,et al.  Attrition of powders and granules at various bends during pneumatic conveying , 2000 .

[25]  Haim Kalman,et al.  Fatigue behavior of impact comminution and attrition units , 2004 .

[26]  Pierre Chapelle,et al.  Computational model for prediction of particle degradation during dilute-phase pneumatic conveying: modeling of dilute-phase pneumatic conveying , 2004 .

[27]  Haim Kalman,et al.  Particle Breakage and Attrition , 2000 .

[28]  Haim Kalman,et al.  Accelerating CFD–DEM simulation of processes with wide particle size distributions , 2014 .

[29]  Haim Kalman,et al.  Attrition control by pneumatic conveying , 1999 .