Schedule:
| PRESENTATION | SPEAKER |
| Investigating Jet Cup Attrition: Experiments and CFD-DEM Simulations | Ravindra Aglave, CD-adapco |
| Population Balance Models of Particle Attrition – Attrition Fragment Distributions and Inference of Parameters | R. Bertrum Diemer, University of Delaware |
| Modeling Catalyst Extrudate Breakage by Impulsive Forces | Jean Beeckman, ExxonMobil Research & Engineering Company |
Investigating Jet Cup Attrition: Experiments and CFD-DEM Simulations
Ravindra Aglave, CD-adapco
Attrition of particles occurs in many industrial processes such as fluidized beds and cyclones. It can be a serious problem. To understand the phenomenon of attrition, it important to investigate the characteristics of materials, the breaking energy supplied by the system, and the distribution of attrition rates among the particles.
Jet cup attrition testing is the most common experimental test for particle attrition in fluidized beds and risers. Arguably, it is supposed to mimic attrition in cyclones which is largest contributed source of attrition in a well-designed unit. However, it is unknown how the components of attrition, abrasion and fragmentation, relate to each other in a jet cup and if that relationship is preserved in a cyclone.
In this preliminary work, simulation of the flow and collision of particles using a coupled DEM (Discrete Element Method) and CFD (Computational Fluid Dynamics) in a Jet Cup is performed to investigate the basics of attrition. This allows to evaluate the distribution of contract forces and how it is affected by various operating and design parameters of the geometry. This can be correlated to the fraction of particles that will break.
Population Balance Models of Particle Attrition – Attrition Fragment Distributions and Inference of Parameters
R. Bertrum Diemer, University of Delaware
In this paper, the ability of the generalized Diemer-Olson-Hill-Ng fragment distribution to describe attrition will be explored including the impact of the fragment distribution on the resulting product size distribution and the inference of fragment distribution parameters by solving the inverse problem for particle breakage.
Modeling Catalyst Extrudate Breakage by Impulsive Forces
Jean Beeckman, ExxonMobil Research & Engineering Company
Here we describe the reduction of the average length to diameter ratio of catalyst extrudates by breakage upon collision with a surface. For this, the authors link the flexural strength of the extrudate described by the Euler-Bernoulli modulus of rupture to the impulsive force the extrudate experiences as described by Newton’s second law. This force balance is applied at the asymptotic length to diameter ratio which is reached after many repeated impacts. This approach yields a dimensionless group as the ratio of the rupture force by bending to the impulsive force by collision and shows that the asymptotic length to diameter ratio is directly proportional with the square root of this group. This dimensionless group also allows one to define a severity of the collision via the impact velocity and the time of contact of the collision. Finally, we also show how the effect of operational severity sequencing and severity conditioning on catalyst breakage can be well described by the method presented.