Contents

Key note lecture 1

Understanding Dust Explosions - The Role of Powder Science and Technology 1

Prof. Rolf Eckhoff - University of Bergen, Norway

Session 1A – Environmental Aspects

1A-1 A nanodustiness test for the assessment of ultrafine aerosol emission from the free fall of nanostructured powders 24

N Ibaseta, B Biscans - Laboratoire de Genie Chimique, Toulouse, FRA

1A-2 Reducing dust emission from falling bulk solids by water spraying - development of a suitable model equation 30

W Höflinger, P Grundnig, G Mauschitz, J Gao - Vienna University of Technology, AUT

1A-3 Water availabel for recycling after the placement of dense phase fly ash slurries 36

T F Bunn, M G Jones, C A Wheeler - The University of Newcastle, AUS

Session 1B – Silodesign

1B-1 Pipe stability in silos 42

J Schwedes, M Morgeneyer, A Cannavaccioulo, T Ittershagen, A Kwade - Institute of Particle Technology, TU Braunschweig, DEU - Universite de Technologie de Compiegne, FRA - Universita di Salerno, ITA

1B-2 Investigation of the anisotropic behaviour of bulk solids. 48

T Ittershagen, J Schwedes, A Kwade – T U Braunschweig, DEU

1B-3 Pipe collapse in the aerated silo discharge of cohesive powders. 54

A Cannavacciuolo, D Barletta, G Donsi, G Ferrari, J Schwedes, M Poletto - University of Salerno, ITA - Technical University of Braunschweig, DEU

Session 1C – Processing

1C-1 Spore inactivation and quality of paprika powder heated by near-infrared radiation 60

N Staack, L Ahrne, E Borch, D Knorr - The Swedish Inst. for Food and Biotechnology, SWE - University of Technology of Berlin, DEU

1C-2 Analysis of granule breakage inside a rotary mixing drum: Experimental study and distinct element analysis 65

H Ahmadian, M Eggert, A Hassanpour, M Ghadiri - University of Leeds, GBR

1C-3 Investigation on the crystallization kinetics of Dextrose Monohydrate using in-situ particle size and supersaturation monitoring 71

A Markande, L Aerts, A Nezzal - Tate and Lyle Europe NV, Aalst, BEL - Nezzal Powder Consulting, Albi, FRA

Session 1D – Electrostatic Charging

1D-1 An analysis of a simple test device for tribo-charging of bulk powders 78

E Supuk, C Seiler, A Hassanpour, M Gahadiri - University of Leeds, GBR

1D-2 Effect of electrostatic charge on particle behaviour in agitation system by parallel discrete element method 84

H Mio, A Shimosaka, Y Shirakawa, J Hidaka - Dosisha University, Kyoto, JPN - Kyoto Fine Particle Technology, Kyoto, JPN

1D-3 Electrostatic charging of powder in pneumatic conveying and aplicability of generated electric signals 90

K Azin, G G Enstad, M Waskaas - Tel-Tek, Dept. POSTEC, NOR - Telemark University College, NOR

Key note lecture 2

Opportunities with Transformative Research in Pneumatic Conveying 95

Prof. George E. Klinzing - University of Pittsburgh, USA

Session 2A – Pneumatic Conveying

2A-1 Advantages of high-pressure dilute-phase conveying systems 115

H Wilms - Zeppelin Silos & Systems Gmbh, Friedrichshafen, DEU

2A-2 Changes in particle size and shape in pneumatic Conveying of Dextrose 123

C Arakaki, C Ratnayake, G G Enstad - Tel-Tek, Dept. POSTEC, NOR

2A-3 Mass flow rate measurement in a pneumatic conveyor using a system identification modelling approach 131

A Sæther, C Arakaki, C Ratnayake, D D Ruscio - Telemark University College, Norway, NOR - Tel-Tek, Dept. POSTEC, NOR

Session 2B – Modelling

2B-1 Numerical investigations for continuous use of gravity silo mixers to smooth periodical inlet fluctuations 140

H. Dauth, K Sommer - TU München-Weihenstephan, DEU

2B-2 CFD visualisation of a pneumatic conveying passive by-pass line 146

D McGlinchey, A Cowell - Glasgow Caledonian University, GBR

2B-3 The application of wavelet transforms to many-body particle interactions 152

N Meejun, U Tuzun, A Skeldon - Univerity of Surrey, Guildford, GBR

Session 2C – Processing

2C-1 Hydrodynamic behaviour of binary mixtures of biomass and alumina in gas fluidized bed 158

K Tannous, E O Gomez, A L B Sauvanel - State University of Campinas, BRA - Federal University of Itajuba-UNIFEI, BRA - University of Oriente, Santiago, CUB

2C-2 Effect of size ratio on the behaviour of granules embedded in a bed of glass beads subjected to shearing: Experimental and DEM analysis 164

H Ahmadian, M Ghadiri - University of Leeds, GBR

2C-3 Production of solid-phase biocatalysts by immobilization of b-galactosidase onto different sized chitosan particles and comparing their catalytic properties 170

E Biro, A Sz Nemeth, C Sisak, T Feczko, J Gyenis - University of Pannonia, Veszprem, HUN - Delft University of Technology, NLD - Hungarian Academy of Science, Budapest, HUN

Session 2D – Characterization

2D-1 Energetic analysis of powder compaction 176

M Röck, T Ittershagen, A Kwade, J Schwedes - T U Braunschweig, DEU

2D-2 Avalanching and breaking of rotating powders layers: A new device to measure cohesion182

A Castellanos - Facultad de Fisicas, Seville, ESP

2D-3 Energy absorption at shear flow and compression of ultrafine powders 188

J Tomas - The Otto-von-Guericke-University, Magdeburg, DEU

Session 3A – Discrete Element Modelling

3A-1 Micromechanics of ultrafine particle adhesion-contact models 194

J Tomas - The Otto-von-Guericke-University, Magdeburg, DEU

3A-2 The stress analysis of high shear mixer granulator using discrete element method (DEM) 200

A Hassanpour, B Ng, J Antony, M Ghadiri - University of Leeds, GBR

3A-3 Representing particle shape in discrete element modelling 206

E Tijskens, F Rioual - Katholieke Universiteit Leuven, BEL - Cemagref, Clermont-Ferrand, FRA

Session 3B – Silodesign

3B-1 A numerical study of the influence of particle friction and wall friction on silo flow 212

J Härtl, J Y Ooi, J Theuerkauf - University of Edinburgh, GBR

3B-2 Pressure development along the walls of a conical hopper with a steep inclination angle 219

S Ding, JM Rotter, JY Ooi, G Enstad - Tel-Tek, Dept. POSTEC, NOR - University of Edinburgh, GBR

3B-3 Experimental investigation of a full scale silo with a large inner tube 228

J Y Ooi, JF Chen, J M Rotter, Z Zhong, J Härtl, M Johnstone, SE Forsmo, B Andreasson, D Thulin - University of Edinburgh, GBR - LKAB, Malmberget, SWE

Session 3C – Processing

3C-1 Drying of heat sensitive materials of high moisture content in mechanically spouted bed of inert particles 235

J Gyenis, E Pallai-Varsanyi, J Toth - University of Pannonia, HUN - Hungarian Academy of Science, Budapest, HUN

3C-2 Prediction of powder agglomeration during the spray drying process 241

A Gianfrancesco, C Turchiuli, D Flick, A Sommer, S Palzer, E Dumoulin - Agroparistech, Massy Cedex, FRA - Nestl Research Center, Lausanne, CHE

3C-3 Analysis of the dynamic response of a mixed-flow grain dryer on the basis of reversing experiments 247

J Mellmann, L Kocsis, I Farkas - Leibniz Inst. of Abricultural Eng. Potsdam-Bornim, DEU - Szent Istvn University, HUN

Session 3D – Characterization

3D-1 Fast determination of particle size distribution by means of the setting rates measured in a microscope sedimentation balance 253

K Sommer, H Dauth - T U München, DEU

3D-2 The apparent viscosity of aerated alumina powder using sphere drop technique 259

K C Williams, M G Jones, G Seswai - University of Newcastle, AUS

3D-3 A study on the effect of air humidity on powder flow properties 265

G Landi, D Barletta, G Donsi, G Ferrari, M Poletto - Universite di Salerno, Fisciano, ITA

Key note lecture 3

Powder Flow and Dust Emissions 271

Prof. Alain de Ryck - Ecole des Mines d'Albi-Carmaux, FRA

Session 4A – Pneumatic Conveying

4A-1 Wear of straight pipeline in pneumatic conveying system 279

V K Agarwal, D Mills - Indian Institute of Technology, New Delhi, IND - Pneumatic Conveying Consultant, Canterbury, GBR

4A-2 Development of an erosion tester - some theoretical & experimental aspects 287

M Wolf, C Ratnayake, W Schubert, G G Enstad - Tel-Tek, Dept. POSTEC, NOR

4A-3 Wear testing of polymers in pneumatic conveying systems 295

H Schneider, H Wilms - Zeppelin Silos & Systems GmbH, Friedrichshafen, DEU

Session 4B – Flowability

4B-1 Flowability testing for product development and quality control 301

T A Bell - DuPont Engineering Research & Technology, Wilmington, USA

4B-2 Prediction of powder bulk flowability using water migration, glass transition and sintering kinetics 307

N Descamps, J Fitzpatrick - University College, Cork, IRL

4B-3 Flow behaviour of non-drained ultrafine limestone particle beds 313

T Mladenschev, J Tomas - Otto-von-Guericke University Magdeburg, DEU

Session 4C – Segregation and Mixing

4C-1 Dispersive and convective transport processes in continuous dynamic powder mixers 319

D Dopfer, K Sommer - T U München, Germany, DEU

4C-2 Quantifying segregation of binary mixtures of particulate solids by image analysis 325

M Eggert, A Hassanpour, N Gedney, M Ghadiri - University of Leeds, GBR

4C-3 Theoretical study of superposition of macro- and micro-scale mixing and its influence on mixing kinetics and mixture quality 331

V Mizonov, H Berthiaux, E Barantseva, C Gatumel - Ivanovo Power Eng. State University, RUS - Ecole des Mines d'Albi, FRA

Session 4D – Characterization

4D-1 Comparison of the stable microsystems texture analyser (TA) with the Schulze ring shear tester 337

A Cowell, D McGlinchey - Glasgow Caledonian Univeristy, GBR

4D-2 Effect of machine dependence on wall failure property measurements, Jenike versus annular shear tester 344

R J Berry, M S A Bradley, O A Angulo, R J Farnish - University of Greenwich, GBR

4D-3 The deformation and breakage behaviour of irregularly shaped particles 351

S Aman, J Tomas, H Kalman, E Rozenblat - Otto-von Guericke Univ. Magdeburg, DEU - Ben- Gurion Univ. of the Negev, ISR

Key note lecture 4

Developments in mechanical transport of bulk solids 357

Prof. Alan Roberts / M G Jones - The University of Newcastle, AUS

Session 5A – Discrete Element Modelling

5A-1 The role of cohesive force in the relationship between the bulk density and the connectivity of the contact network of a granular material 371

F A Gilabert, J-N Roux, A Castellanos - University of Seville, ESP - Lab. des Materiaux des Structures du Genie Cevil, Champs-sur-Marne, FRA

5A-2 Multi-sphere ellipsoidal particles in DEM simulations of piling problem 378

D Markauskas, R Kacianauskas, A Dziugys - Vilnius Gediminas Tech. Univeristy, LTU - Lithuanian Energy Institute, LTU

5A-3 Discrete element simulation of a stockpile with spherical and non-spherical particles 384

C Zhou, J Ooi - University of Edinburgh, GBR

Session 5B – Silodesign

5B-1 Experimental and calculated loads on "cone in cone"- inserts 391

T Schuricht, C Fürll, G G Enstad - Leibniz-Institut für Agrartechnik Potsdam-Bornim, DEU - Tel-Tek, Dept. POSTEC, NOR

5B-2 An experimental study of cone-in-cone inserts configuration in a full-scale silo 397

J Härtl, J Y Ooi, G G Enstad - University of Edinburgh, GBR -Tel-Tek, Dept. POSTEC, NOR

5B-3 Tracer technique for flow profile of solid in silo 405

S K Nadngavkar, R Pitchumani, B Pitchumani - Indian Institute of Technology, New Dehli, IND

Session 5C – Segregation and Mixing

5C-1 Investigation into the segregation of alumina on board ships and in the silos 418

J Scotland, A Dyrøy, E Tveten - Malvern Process Systems, GBR - Hydro Aluminium, NOR

5C-2 Controlling particle segregation with a specially shaped standpipe 424

W Halford, O Kennedy, P Arnold - Centre for Bulk Solids and Particulate Technologies, University of Wollongong, AUS

5C-3 Experimental investigation on air current segregation in cylindrical laboratory silos 430

S Zigan, R B Thorpe, U Tuzun, G G Enstad - University of Surrey, GBR - Tel-Tek, Dept. POSTEC, NOR

Session 5D – Handling

5D-1 The reliable way to convey inconsistent materials such as drill cuttings for all applications 437

G Burnett - Brandt NOV, Aberdeen, GBR

5D-2 Startup and running forces on bulk solids feeders: Experimental findings versus available models 450

CPM Holmes, MSA Bradley, AR Reed, RJ Berry - Jenike & Johansen Ltd, Toronto, CAN - The University of Greenwich, Chatham, GBR

5D-3 Transitional concentration measurement of powder flow in vertical pipe for petroleum refinery process 458

T Zhao, M Takei - Nihon University, Tokyo, JPN

Session 6A – Pneumatic Conveying

6A-1 Analysis of trasient behaviour in the dense phase conveying of powders 464

M G Jones, K C Williams, S Busteed - Centre for Bulk Solids and Particulate Technologies, The University of Newcastle, AUS

6A-2 Evaluation of scale-up procedures for fluidised dense-phase pneumatic conveying design 470

S S Mallick, P W Wypych - University of Wollongong, AUS

6A-3 Evaluation of pressure gradient data for the pneumatic conveying of sand 476

A N H Rao, D Mills, V K Agarwal - SJCE College, Mysore, IND - Pneumatic Conveying Consultant, Canterbury, GBR - Indian Institute of Technology, New Delhi, IND

Session 6B – Modelling

6B-1 Review of models for predicting the discharge rates of bulk particulates from silos and bins 484

K Ariza-Zafra, R J Berry, M Bradley - The Wolfson Centre for Bulk Solids Handling Tech., University of Greenwich, GBR

6B-2 Can granular media be modelled in terms of continuum mechanics? 493

E F Grekova, A Castellanos, S N Gavrilov - University of Seville, ESP - Institute for Problems in Mechanical Engineering - Russian Academy of Sciences, RUS

6C-3 Deformation and breakage behaviour of dry cylindrical agglomerates 499

S Antonyuk, J Tomas - Otto-von-Guericke-Univ. of Magdeburg, DEU

Session 6C – Segregation and Mixing

6C-1 Segregation of bulk particulates through multiple process handling steps 505

R J Farnish, P Kulkani, M S A Bradley - The Wolfson Centre for Bulk Solids Handling Tech., University of Greenwich, GBR

6C-2 Reliable flow of powders in blending silos - New blender design as a chance for process optimization 511

H Hoppe, M Dürr - Coperion Waeschle GmbH & Co. KG, Wingarten, DEU

6C-3 Assessment of methodologies for scaling-up of high shear mixer granulators 520

N Rahmanian, M Ghadiri, Y Ding, X Jia - University of Leeds, GBR

Session 6D – Handling

6D-1 Reliable handling of Al2O3-powder in the aluminium smelter industry 526

H Hoppe, S Skirde - Coperion Waeschle GmbH & Co. KG, - Weingarten, DEU

6D-2 Development and installation of a new alumina feeding system to aluminium pots 532

S Ose, G Wedde, A Sørhus, O Bjarnø, J K Bøckman - Alstom Norway AS, Oslo, NOR

6D-3 Effective design of belt feeder interfaces to achieve reliable operation 539

J Carson, F Cabrejos, M Rulff - Jenike & Johansson, USA, - Jenike & Johansson, CHL - Jenike & Johansson, CAN

Key note lecture 5

Size Reduction of Particles 545

Prof. Haim Kalman - Ben-Gurion University of the Negev, ISR

Session 7A – Pneumatic Conveying

7A-1 Investigation of the air gap and slug length ratio in slug flow pneumatic conveying 555

T Krull, K C Williams, S Hoette, M G Jones - Centre for Bulk Solids and Particulate Technologies, The University of Newcastle, AUS

7A-2 Experimental study of dilute vertical pneumatic transport using PIV 561

A Mathisen, B Halvorsen, M C Melaaen - Tel-Tek, Dept. GassTEK, NOR -Telemark University College, Porsgrunn, NOR

7A-3 Effect of elbow geometry on pressure drop in upstream straight sections during dilute phase pneumatic conveying 568

N Vasquez, K Jacob, A Voets - The Dow Chemical Company, Midland, USA - RWTH Aachen University, DEU

Session 7B – Modelling

7B-1 Validation of particle flow through a conveyor transfer hood via particle velocity analysis 574

D B Hastie, A P Gima, P W Wypych - University of Wollongong, AUS

7B-2 Determination of the stress distribution during the die compaction of powders by numerical simulation 580

J D Prigge, K Sommer - Technische Universität München, DEU

7B-3 Modelling dosator filling and discharge of powder 586

O A Angulo, MSA Bradley, RJ Berry, RJ Farnish - University of Greenwich, GBR

Session 7C – Caking

7C-1 A force-displacement tester for investigating the caking powders 592

J Fitzpatrick, N Descamps, E O'Callaghan, J O Flynn - University College of Cork, IRL

7C-2 Caking of binary powder mixtures of crystalline and amorphous particles 598

E Schreyer, K Sommer - Nestl Product Technology Centre, Singen, DEU

7C-3 Caking strength of granulated clay under frozen conditions 604

T Deng, M Bradley, RJ Berry, J Kostuch - The Wolfson Centre for Bulk Solids Handling Tech., University of Greenwich, GBR - Imerys Minerals Ltd, Cornwall, GBR

Session 7D – Milling and Grinding

7D-1 Study of sub-micron milling mechanism by means of population balance modelling 610

S L A Hennart, G M H Meesters, W J Wildeboer - DSM Food Specialties, Delft, NLD - DSM, Delft University of Technology Delft, NLD

7D-1 Effect of pH variation in wet grinding system 617

S Sakthivel, V V Krishnan, B Pitchumani - Indian Institute of Technology, New Dehli, IND

7D-3 Numerical and experimental study of particle motion and classification in jet milling 624

T Brosh, Y Batat, H Kalman, A Levy - Ben-Gurion University of the Negev, ISR

Key note lecture 6

Powder Technology - quo vadis ?

Prof. Gisle Enstad - Tel-Tek, Dept. POSTEC, NOR

Session 8A – Pneumatic Conveying

8A-1 Wear resistant components in mineral pneumatic conveying systems 630

B Zinser - Coperion Waeschle GmbH & Co. KG, Weingarten, DEU

8A-2 Motion of coarse particles in a horizontal pneumatic pipe 640

H Tashiro, Y Tomita - Kurume Institute of Technology, JPN - Kyushu Institute of Technology, JPN

8A-3 Measurement of dense-phase pipe forces in an industrial-size conveying system 646

T Fatho, H Schneider, H Wilms - Zeppelin Silos & Systems GmbH, Friedrichshafen, DEU

Session 8B – Silodesign

8B-1 Silo discharge of an ultrafine cohesive powder by vibrating hoppers 654

G Kache, D Pötch, A Haack, J Tomas - Otto-von-Guericke-University Magdeburg, DEU

8B-2 Prediction of flow mode during silo discharge and its preliminary verification 660

S Ding, M Jecmenica, G Enstad, JY Ooi, JM Rotter - Tel-Tek, Dept. POSTEC, NOR - Telemark University College, NOR - University of Edinburgh, GBR

8B-3 Numerical simulation study upon granular materials flow in silos 668

G Xiao, D Xu, S Ding - Soochow University, Suzhou, CHN - Univeristy of Archi. & Tech, Xi'an, CHN - Tel-Tek, Dept. POSTEC, NOR

Session 8C – Coating

8C-1 Dry coating process using polysaccharides in a Pan coating system 674

L Bilancetti, C Loisel, D Poncelet, F Depypere, K Dewettinck, J G Pieters - ENITIAA, Nantes, FRA - Ghent University, BEL

8C-2 Water-soluble cellulose derivatives as coating agents in fluidized bed processing 680

K Nienaltowska, F Depypere, F Ronsse, J Pieters, K Dewettinck - Ghent University, BEL

8C-3 Dry particle-High impact-Coating of biopowders-Coating strength of biopowders 687

S Ötles, A Chamayou, L Galet, O Lecoq, J A Dodds - Ecole des Mines d'Albi, FRA

Session 8D – Handling

8D-1 Performance analysis of a rotary spreader 695

A W Roberts, M G Jones - Centre for Bulk Solids and Particulate Technology, The University of Newcastle, AUS

8D-2 Determination of the undesired consolidation by mechanical vibrations at cohesive powder flow 701

A Haack, G Kache, S Winkler, J Tomas - Otto-von-Guericke University Magdeburg, DEU

8D-3 Influence of crystal properties in powder flow behaviour 707

R Beck, D Malthe-Sørenssen, J-P Andreassen, T Nysæter, G G Enstad - NTNU, Trondheim, NOR - Tel-Tek, Dept. POSTEC, NOR

POSTERS

P01 Morphology and viscoelastic behaviour of HPMC cast films as model for "quality by design"

approach for coating characterization 726

G Perfetti, K Jansen, H Wildeboer, G. Meesters - Delft University of Technology, NLD - DSM Food Specialties, Delft, NLD

P02 Hygenic design for components of pneumatic food conveying systems 732

B Zinser, M Stephan - Coperion Waeschle GmbH & Co. KG, Weingarten, DEU

P03 Description of the flow in the silo model 738

I Sielamowicz - Bialystok Technical University, POL

P04 Mechanical attrition of sodium chloride particles in a gas fluidized bed 744

V O P Valdo, K Tannous - State University of Campinas, BRA

P05 Population balance modelling of fluidized bed spray granulation 750

C Turchiuli, T Jimenez, B Broyart, E Dumoulin - Agroparistech, Massy Cedex, FRA

P06 Characterisation of flowability of cohesive powders using indentation 756

C Wang, A Hassanpour, M Ghadiri - University of Leeds, GBR

P07 Particle charging in nanofludization 762

M A S Quintanilla, J M Valverde, M J Espin, A Castellanos - University of Seville, ESP

P08 Stress states and porosity within horizontal slug by dense-phase pneumatic conveying 768

I Lecreps, K Sommer - Technische Universität München, DEU

P09 Influence of technological parameters on compression and flow behaviour of cohesive powders 774

M Stasiak, J Tomas, M Molenda, P Müller - Otto-von-Guericke- University, Magdeburg, DEU - Polish Academy of Science, Lublin, POL

P10 Preliminary investigation into magnetite powder's magnet shielding effect on drilling fluid 780

S Ding, F von Hafenbrädl, A Saasen, P A Amundsen - Tel-Tek, Dept. POSTEC, NOR -Statoil Hydro ASA, NOR -University of Stavanger, NOR

P11 Methods and equipment of measuring loads of pressure of bulk materials against silo wall and bottom 786

M Kaminski, M Maj - Technical University of Wroclaw, POL

P12 Non-intrusive measurement of particle trajectories and velocities in pneumatic conveying pipelines using positron emission particle tracking technique (PEPT) 792

AR Chaudhry, MSA Bradley, AR Reed - Portasilo Bulk Handling Systems, York, GBR - The University of Greenwich, London, GBR

P13 Micromechanics of ultrafine particle adhesion - energy absorption at contact 798

J Tomas - The Otto-von-Guericke University, Magdeburg, DEU

P14 Direct measurement of flavouring powder adhesion onto food surface using a novel adhesion tester 804

E Ermis, R J Farnish, R J Berry, M S A Bradley - University of Greenwich at Medway, Kent, GBR

P15 Aerodynamic dispersion of cohesive powders: The effect of interparticle cohesion 812

G Calvert, A Hassanpour, M Ghadiri - University of Leeds, GBR

P16 Flow in vending machine canisters and dosage 818

M Ramaioli, T M Liebling - Nestl Research Centre, Lausanne, CHE - Ecole Polytechnique Federeale de Lausanne, CHE

P17 Application of the theory of Markov chains to describe multi-stage particle breakage due to fatigue 824

V Mizonov, H Kalman, H Berthiaux - State University, Ivanovo, RUS - Ben-Gurion Univerisy of the Negev, ISR - Ecole des Mines d'Albi, FRA

P18 Particle breakage in agitated dryers 830

C Hare, M Chadiri, R Dennehy - University of Leeds, GBR - GlaxoSmithKline Particle Sciences Group, Kent, GBR

P19 Analysis of flow velocities in converging models 837

I Sielamowicz - Bialystok Technical University, POL ■

Understanding Dust Explosions.

The Role of Powder Science and Technology

R.K. Eckhoff

Professor emeritus, University of Bergen, Dept. of Physics and Technology, Bergen, Norway.

Scientific and technical adviser, Øresund Safety Advisers AB, Malmö, Sweden.

Abstract

Dust explosions in the process industries practically always start inside process equipment such as mills, dryers, mixers, classifiers, conveyors, and storage silos and hoppers. For any given dust type the ease with which dust clouds ignite and the rates with which they burn, vary considerably with factors well known in powder science and technology. The key factors include the primary particle size distribution of the dust, the degree of de-agglomeration of the dust particles in the cloud, the dust concentration distribution in the cloud, and the cloud turbulence. The last three factors are entirely dependent on the actual process situation in which the dust cloud is generated and sustained. The paper first discusses influences of these factors on the ignition sensitivity and explosion violence of dust clouds. Secondly the concept of inherently safe process design to prevent accidental dust explosions is discussed, using design of hoppers and silos as an example.

Then some consequences of the mentioned factors in design of mitigatory measures such as explosion isolation, explosion venting, and automatic explosion suppression, are discussed. The role of powder science and technology in understanding development and propagation of secondary dust explosions is also considered.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

A NANODUSTINESS TEST FOR THE ASSESSMENT OF ULTRAFINE AEROSOL EMISSION FROM THE FREE FALL OF NANOSTRUCTURED POWDERS

Nelson IBASETA, Batrice BISCANS

Laboratoire de Gnie Chimique CNRS UMR 5503

Toulouse FRANCE

ABSTRACT

A nanodustiness test is proposed as a useful device for the assessment of ultrafine aerosol emission by free falling nanopowders. This test is made of a 180*50*80 cm chamber, where the nanostructured powder is stocked in a silo with variable height. After the powder fall, the size distribution and concentration of the emitted aerosol are measured by an Electric Low Pressure Impactor (ELPI). Three representative powders have been tested: TiO2, SiO2 and Al2O3. The emitted aerosols have a bimodal distribution in all cases. One of the maxima corresponds to the micrometric nanostructured agglomerates that constitute the powder, whereas the other one represents the ultrafine aggregates coming from the break-up of the coarser agglomerates. Ultrafine aggregates concentration is not affected by the experimental conditions (height of fall, dropped mass), but is strongly influenced by the structure of the powder.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

REDUCING DUST EMISSIONS FROM FALLING BULK SOLIDS BY WATER SPRAYING - DEVELOPMENT A SUITABLE MODEL EQUATION

W. Höflinger*, P. Grundnig, G. Mauschitz, J.Gao

Vienna University of Technology, Institute of Chemical Engineering,

Getreidemarkt 9, A-1060 Vienna

ABSTRACT

One of the main origins of fugitive dust emission arises from bulk handling in quarries or mines, in particular, from bulk materials falling from a hopper or a conveyor belt. Waterspraying systems, using two-phase nozzles, are one of the methods to suppress such dust emission. In a laboratory bulk falling experimental apparatus, where in the enclosed box the spraying nozzle is situated, the generated dust is sucked off and the PM10 dust concentration were measured for different water flows and different nozzle positions. In order to develop a design method for the spraying device, a model was developed, by which the water flow consumption together with the relative humidity of the sucked- in air can be related to the reduction of PM10 dust emission. This model was developed in analogy to a deep bed filtration model, where the deep bed filter layer has a similar function like the droplet swarm of the spraying nozzle for the particle retention. This model can be used to clear-up in more detail the responsible physical separation mechanism and will led further to an optimal design of the spraying device.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

EFFECT OF SIZE RATIO ON THE BEHAVIOUR OF PARTICLES EMBEDDED IN A BED OF GLASS BEADS SUBJECTED TO SHEARING: EXPERIMENTAL AND DEM ANALYSIS

H. Ahmadian, A. Hassanpour and M. Ghadiri

Institute of Particle Science and Engineering

University of Leeds, Leeds LS2 9JT, UK

Abstract

The stress nature and breakage behaviour of a particle inclusion embedded in a matrix of particles subjected to shearing (normal pressure and strain rate of 20 kPa and 10 to 13 s-1, respectively) is investigated. In previous studies the size ratios (ratio of the diameter of inclusion to diameter of surrounding particles) of 3 to 15, more applicable to the granulation process, were investigated. In this work, the effect of lower size ratios, ranging from 0.71 to 2.5, on the stress ratio (ratio of deviatoric stress to hydrostatic stress) are investigated by Distinct Element Method (DEM) simulations. It is shown that as the size ratio is decreased below 2.5, the number of contacts around the embedded particle decreases and the maximum stress ratio drastically increases, promoting particle breakage. This trend is consistent with experimental observations, where the granule breakage increases with a decrease in size ratio.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

PRODUCTION OF SOLID-PHASE BIOCATALYST BY IMMOBILIZATION OF –GALACTOSIDASE ONTO MICRO-SIZED CHITOSAN PARTICLES

E. Biro (1,2), A. Sz.-Nemeth (1), C. Sisak (1), T. Feczko (1,3), J. Gyenis (1)

1. University of Pannonia, Faculty of Information Technology, Research Institute of Chemical and

Process Engineering, 10 Egyetem Street, biro@mukki.richem.hu,

HU-8200 Veszprem, HUNGARY

2. Delft University of Technology, Department of Chemical Technology, Particle Technology

Group, 136 Julianalaan,

NL-2628 BL Delft, THE NETHERLANDS

3. Hungarian Academy of Science, Chemical Research Centre, Institute of Materials and

Environmental Chemistry, 59-67 Pusztaszeri Street,

HU-1025 Budapest, HUNGARY

Abstract

Chitosan microparticles have been prepared by emulsion cross-linking method. Glutaraldehyde was used as cross-linking agent, which allows covalent attachment of the enzyme. A wide range of particle size could be produced using the emulsion cross-linking method. Practically, any desired size between 20 and 500 m could be reached by properly choosing the type and concentration of surfactant.

The obtained microparticles proved to be suitable for immobilization of -galactosidase. -Galactosidase enzyme was immobilized onto microparticles to obtain solid-phase biocatalyst. The biocatalysts fixed on microspheres were stable at 4ºC for 3. The immobilized -galactosidase proved to be very stable and operated with almost the same yields throughout the performed 10 runs.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ENERGETIC ANALYSIS OF POWDER COMPACTION

M. Röck1, T. Ittershagen2, A. Kwade2 and J. Schwedes2

1. Evonik Degussa GmbH, Process Technology & Engineering, Particle Processing

Hanau-Wolfgang, GERMANY

2. Institute for Particle Technology, TU Braunschweig

Braunschweig, GERMANY

Abstract

Compaction of powders is of interest from both industrial and academic points of view. The compaction behaviour comprises the interaction of bulk density with porosity and compaction stress and is important to characterize bulk solids. In general the compaction behaviour of a powder is plotted using a porosity-stress diagram, referred to as a compaction curve. The aim of this paper is to present compaction curves obtained for different compaction procedures using the True Biaxial Shear Tester. The True Biaxial Shear Tester allows the investigation of uni-axial and bia-xial compaction procedures and additionally a stair-like compaction procedure with uni-axial

compaction in the x-direction followed by uni-axial compaction in the y-direction. These compaction procedures are analysed according to the energy input required to reach the final porosity. This approach allows the energetic and thus the economic optimization of the compaction process of powders.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

AVALANCHING AND BREAKING OF ROTATING POWDER LAYERS:

A NEW DEVICE TO MEASURE COHESION

A. Castellanos

Faculty of Physics, University of Seville, Avda. Reina Mercedes s/n, 41012 Seville, Spain

Abstract

We study the effect of the combined action of centrifugal and gravitational forces on the avalanching and breaking of vertical and horizontal layers made of cohesive powders. Because the layers are thin we may safely assume uniformity of the material properties across them. In both cases, at a critical value of the angular velocity the shear stresses are large enough to drive material avalanches. The analysis of the vertical layer is based on the Coulomb method of wedge, and allow us to determine the cohesion and angle of internal friction of the powder.

For the analysis of the horizontal spinning disk we have devised a simple physical model, that allows us to obtain the value of the tensile strength. The results show that both cohesion and tensile strength are of the same order of magnitude, thus indicating that the yield locus is curved to the left of the origin. Since the boundary and initial conditions are better controlled for vertical layers, we have developed a novel device [1] enabling us to measure the angle of internal friction

and cohesion of loosely consolidated cohesive granular materials. As further checks we have estimated experimentally the angle of internal friction and cohesion of powder samples compacted by previous vertical vibration. These parameters have been also measured using an independent standard technique (automated Schulze ring shear tester) and the values obtained

agree within the experimental indeterminacy with the values obtained from our powder tester.

Some advantages of the new powder tester are: i) it needs a quite reduced mass of material for testing, ii) the test is of short duration, typically of the order of minutes, iv) the shear on the sample is not induced by external mechanical parts, which avoids problems such as wall sliding, v) the fracture inside the sample is clearly identified by direct visualization of the shearing process, and, vi) it allows for testing at very small consolidations.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ENERGY ABSORPTION AT SHEAR FLOW AND COMPRESSION OF DRY ULTRAFINE POWDERS

Jürgen Tomas

Mechanical Process Engineering, The Otto-von-Guericke-University

Universitätsplatz 2, D – 39 106 Magdeburg, Germany

Abstract

For the non-rapid frictional shear flow in powder handling practice, the fundamentals of cohesive powder consolidation and flow are briefly explained by combination of particle micromechanics and powder continuum mechanics. With this physical basis, incipient powder consolidation, yield and cohesive steady-state flow are explained. These yield loci are completely described only

with three material parameters, i.e., angle of internal friction, stationary angle of internal friction, isostatic tensile strength of an unconsolidated powder and the influence of averaged pressure during pre-consolidation. Next, the physical basis of the enormous compressibility of cohesive powders is explained by compression rate and compression function. This powder compression behaviour is

classified by a compressibility index n (with 0 ≤ n < 1) as an additional constitutive parameter. As consequence of poor flowability and large compressibility, ultrafine powders can absorb large amounts of energy during compression and shear flow. Exemplary, the flow properties of an ultrafine limestone powder are shown. These constitutive models are used to evaluate shear test results

for apparatus design to ensure reliable powder flow. Finally, conclusions are drawn concerning particle stressing, powder handling and product quality assessment in processing industries.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

MICROMECHANICS OF ULTRAFINE PARTICLE ADHESION – CONTACT MODELS

Jürgen Tomas

Mechanical Process Engineering, The Otto-von-Guericke-University

Universitätsplatz 2, D – 39 106 Magdeburg, Germany

Abstract

Dry, ultrafine, cohesive and compressible powders (particle size d < 10 µm) show a wide variety of typical flow problems that cause insufficient apparatus and system reliability of processing plants. Thus, it is very essential to understand the fundamentals of particle adhesion with respect to product quality assessment and process performance in particle technology.

Comprehensive models are shown that describe the elastic-plastic force-displacement and frictional moment-angle behaviour of adhesive contacts of isotropic smooth spheres. Using the model stiff particles with soft contacts, a sphere-sphere interaction of van der Waals forces without any contact deformation describes the stiff attractive term. The soft micro-contact response generates a flattened

contact, i.e. plate-plate interaction, and increasing adhesion. These increasing adhesion forces between particles directly depend on this frozen irreversible deformation. Thus, the adhesion force is found to be load dependent. It essentially contribute to the tangential forces in an elastic-plastic frictional contact with partially sticking within the contact plane and microslip. The load dependent rolling resistance and torque of mobilized frictional contact rotation (spin) is also shown.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

THE STRESS ANALYSIS OF HIGH SHEAR MIXER GRANULATOR USING DISCRETE ELEMENT METHOD (DEM)

A. Hassanpour, B. Ng, S. J. Antony, M. Ghadiri

Institute of Particle Science & Engineering

University of Leeds, Leeds, LS2 9JT, U.K.

Abstract

High shear mixer granulators are typically found in pharmaceutical and detergent industries, and are capable of reducing processing time and producing agglomerates of high strength and density. Generally, several granulation scale-up stages are involved before commencing production. During such scale-up processes, the mechanics of particle interactions and prevailing levels of compressive stresses and strains are affected by the variation in hydrodynamics within granulators of different scales. This in turn affects the final structure of the agglomerates. In this paper the effect of velocity field of two different scales of high shear mixer granulator (1 l and 5 l) on the structure of the evolved agglomerates is analysed. The study is based on computer simulation using Distinct Element Method (DEM). A single agglomerate is generated using DEM and is placed in a bed of primary particles. The bed is sheared by imposing a velocity field obtained from Positron Emission Particle Tracking (PEPT) measurements on 1 l and 5 l granulators which were scaled up based on constant shear stress condition. The results show that when the velocity profile of the 1 l granulator is used, the resulting agglomerate is more elongated, has a smaller packing fraction and therefore is weaker.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

REPRESENTING PARTICLE SHAPE IN DISCRETE ELEMENT MODELLING

E. Tijskens (1) and F. Rioual (2)

1. DEM Research Group, K.U.Leuven

Leuven, BELGIUM

2. Cemagref

Clermont-Ferrand, FRANCE

Abstract

An overview is given of techniques to represent particle shape in discrete element models. The authors discuss issues related to computational complexity, implementation, experimental determination of model parameters. Finally, they present a new shape model based on rounded polyhedra.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

A NUMERICAL STUDY OF THE INFLUENCE OF PARTICLE FRICTION AND WALL FRICTION ON SILO FLOW

J. Härtl (1, J.Y. Ooi (1) , J. Theuerkauf (2)

1. Institute for Infrastructure & Environment, The King's Buildings,

University of Edinburgh, Edinburgh EH9 3JL, U.K.

2. The Dow Chemical Company, Core R&D, EP&S, Solids Processing Laboratory,

2301 North Brazosport Blvd, Freeport, TX, USA.

Abstract

A numerical study of flow and pressure in a silo using the discrete element method is presented. An attempt was made to use the Jenike direct shear tests to calibrate the DEM material model. The results show that DEM, using non-spherical particles, can produce reasonable predictions of both the flow behaviour and the wall pressure distribution in a silo. Temporally averaged pressure distributions are found to be in good agreement with established silo theories. A summary of the parametric study to explore the influence of particle and wall friction on the criteria for mass flow and funnel flow is also presented.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

Pressure development along the walls of a conical hopper with a steep inclination angle

S. Ding (1), M. Rotter (2), J. Ooi (2) and G. Enstad (1)

1. POSTEC av Tel-Tek, 3914 Porsgrunn, Norway

2. The School of Engineering and Electronics, The University of Edinburgh, Scotland

Abstract

A progressive filling approach was adopted in a numerical effort to represent the filling process of particulate solids. It was implemented in a finite element analysis to investigate the development of loads on a conical steep hopper during filling. The loads developed along the walls of the hopper in a concentric-filling were addressed. An analysis of the conventional so-called ‘switch on’ filling was also conducted. The predictions of such numerical approaches are compared with predictions of classical theories for the loads acting on the wall of the hopper.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

EXPERIMENTAL INVESTIGATION OF A FULL SCALE SILO WITH A LARGE INNER TUBE

J.Y. Ooi (1), J.F. Chen (1), J.M. Rotter (1), Z. Zhong (1), J. Härtl (1), M. Johnstone (1), S.E. Forsmo (2),

B. Andreasson (2), D. Thulin (2)

1. School of Engineering & Electronics, University of Edinburgh, Edinburgh EH9 3JL, U.K.

2. LKAB, Malmberget SE-983 81, Sweden.

ABSTRACT

This paper describes an investigation to support the design of full scale silos with large perforated inner concrete tubes. The group of silos are blasted and formed out of solid rock underground to store iron ore pellets. A 1:25th scale model was constructed to investigate the flow pattern and stress regime for the pellets and to evaluate the loading on the concrete tube. A total of 15 tests were conducted to measure the flow pattern using a combination of top surface observations and residence times of tracers, to measure pellets stresses and to observe the structural response of the inner tube subject to the pellets filling and discharge using fibre optics strain

gauges. The main test results and the key findings relating to the flow pattern measurements are described in this paper.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

DRYING OF HEAT SENSITIVE MATERIALS OF HIGH MOISTURE CONTENT IN MECHANICALLY SPOUTED BED OF INERT PARTICLES

Janos Gyenis (1) , Elisabeth Pallai –Varsnyi (1) and Judit Tth (2)

1. Research Institute of Chemical and Process Engineering,

University of Pannonia, H-8200 Veszprm, HUNGARY

2. Institute of Materials and Environmental Chemistry,

Chemical Research Center, Hungarian Academy of Sciences,

H-1025 Budapest, HUNGARY

Abstract

In drying operation the material characteristics such as heat sensitivity, moisture content and particle size are of great importance, which should be taken into account in selection of proper design and conditions for the process. Rigorous quality requirements, i.e. gentle drying of heat sensitive materials, stable, well-controlled and economic operation can be fulfilled by using Mechanically Spouted Bed (MSB) dryer with inert particles developed to eliminate some drawbacks of the conventional spouted bed dryers. In this paper the construction and the main

features of MSB-dryer are presented. Different tasks with special quality demands, namely drying of bovine serum albumin and moisture removal from tomato pulp of thermoplastic behaviour, and a method to accomplish these requirements are shown.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

PREDICTION OF POWDER AGGLOMERATION DURING SPRAY DRYING PROCESS

Gianfrancesco A. (1), Turchiuli C.1, Sommier A. (1), Palzer S. (2), Dumoulin E. (1)

1. Agroparistech, SPAB Department, UMR GenIAl 1145

1 avenue des Olympiades, 91300 Massy (France)

2. Nestl Research Center, Food Science and Technology Department.

Vers-Chez-Les-Blanc CH-1000 Lausanne 26 (Switzerland)

Abstract

Spray drying process is a convective drying of liquid droplets through their surface by hot air. Initially drop water activity is close to 1 and drying is fast. Then drop surface aw decreases and viscosity increases reaching a sticky rubbery state. Drying being fast, this behavior is generally observed close to the atomizer. But, for some specific conditions and materials, sticking is observed along the chamber, on walls or between particles (agglomeration).

In this study air properties evolution (temperature, relative humidity) during drying was considered as representative of drop drying. Trials were performed with a model product (maltodextrin DE12) in a co-current pilot spray dryer, varying parameters as liquid flow rate (25-50-75 mL.min-1), air temperature (144-174-200°C), air flow rate (80-110 kg.h-1) and rotary atomizer speed (22500 to 30000 rpm). From air cartographies and powders properties the evolution of temperature and mean water content of drying drops was described. These results combined with sorption isotherms and glass transition temperatures allowed to predict particles stickiness during drying.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ANALYSIS OF THE DYNAMIC RESPONSE OF A MIXED-FLOW GRAIN DRYER ON THE BASIS OF REVERSING EXPERIMENTS

J. Mellmann (1), L. Kocsis (1) and I. Farkas (2)

1. Department of Post Harvest Technology,

Leibniz Institute of Agricultural Engineering Potsdam-Bornim (ATB),

Potsdam, GERMANY

2. Department of Physics and Process Control,

Szent Istvn University, Gödöll, HUNGARY

Abstract

Mixed-flow dryers are widely used for hot-air drying of grain, maize, and rice and considered to be well-engineered. Regardless there is still a need to optimize the process control as well as the dryer apparatus. To produce grain with equilibrium moisture content is

an important objective of drying process control. However, fluctuations of grain moisture content at the dryer entrance are still a major problem resulting in quality and economic losses due to under-drying or over-drying. A multitude of disturbance variables, nonlinearity, and long reaction times complicate the dryer control. Therefore, the authors aim to develop a new model-based control system for the mixed-flow dryer enabling the operator to superiorly equalize the fluctuations of the moisture content of the dried grain. The objective of this study

is to analyse the dynamic response of the dryer on the basis of reversing experiments. As a result, model parameters for the process control model can be estimated. For this purpose jump functions of the inlet moisture content are inserted at the dryer entrance. The response

functions measured at the dryer outlet are evaluated.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

FAST DETERMINATION OF PARTICLE SIZE DISTRIBUTION BY MEANS OF THE SETTLING RATES MEASURED IN A MICROSCOPE

“SEDIMENTATION BALANCE”

K. Sommer (1), H. Dauth (1)

1. Technische Universität München, Center of Life Sciences Weihenstephan, Lehrstuhl für

Maschinen- und Apparatekunde, GERMANY

Abstract

The settling rate and the calculated equivalent diameter derived from that is one of the best and most important values to determine the particles size. A lot of processes dealing with particles are influenced by the settling rate, e.g. air separators, centrifugal separators or cyclones as well as the separation of particles from air or fluids. So far two well known sedimentation analysis are used to determine the particle size distribution by means of the settling rate, the sedimentation balance or the pipette analysis. Both methods have a few drawbacks. A long analysis time caused by small particles associated with the risk of thermal convection. In the case of the sedimentation

balance a large amount of product is needed, because it is necessary to weigh the sediment.

Based on this background knowledge a new method to measure the particle size distribution by means of the equivalent diameter calculated from the settling rate is being developed. The aim was to avoid the known drawbacks of the common analysis methods. Therefore an inverted microscope is used to measure the increase of the settled particles at the bottom of a small cuvette (settling tank) by automatic image analysis. Hereby the measured quantity is not the mass but the increase of the total projected area. In addition the method needs just a small amount of particles which means it has a small sedimentation height and a relatively quick sedimentation time. As a result of the illumination in an inverted microscope from the top, a thermal convection could nearly be avoided. The results with selected products of spherical and non spherical shape will be presented and compared with other particle size measurement methods e.g. laser diffraction.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

THE APPARENT VISCOCITY OF AERATED ALUMINA POWDER USING A SPHERE DROP TECHNIQUE

K.C. Williams, G. Seswai and M.G. Jones

Centre for Bulk Solids and Particulate Technologies

University of Newcastle, AUSTRALIA

Abstract

With the increase in the development of CFD based codes for gas-solids flows, the viscous nature of gas-solid behaviour is becoming an increasing important parameter to determine. Generally, the assumption on the viscous behaviour of gas-solid flows is that the viscosity is only related to the interstitial gases rate of deformation rather than the overall gas-solids deformation response. This deformation response can vary from the conveying gas viscosity response for dilute gas-solid systems to apparent gas-solid viscosity behaviour for material that exhibits high air retention. (e.g. fluidised material). The apparent viscosity calculations for an alumina powder were based on the resistance force of a sphere passing vertically through the aerated alumina bed. Initial

results of the drag force of the sphere found that its associated co-efficient of drag within the aerated bed could vary between 1.2 and 2.5 with the aerated alumina bed exhibiting shear thinning (pseudo-plastic) viscosity behaviour.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

A STUDY ON THE EFFECT OF AIR HUMIDITY ON POWDER FLOW PROPERTIES

Giovanna Landi, Diego Barletta, Giorgio Dons, Giovanna Ferrari and Massimo Poletto

Department of Chemical and Food Engineering, University of Salerno

Via Ponte don Melillo, I-84084 Fisciano (SA), Italy.

Abstract

In this work the effect of air humidity on the flow properties of a 48 µm glass beads powder was studied by means of a ring shear tester. Powder sample moisture content was conditioned by humid air in a fluidization column. In spite of the very low moisture contents in the powder (<0.2%) obtained by this technique, a significant change in the powder cohesion was observed. The Kelvin equation was used to infer on the pressure increase inside the capillary bridge and the resulting typical interparticle force. This result was used to derive the powder tensile strength following the Rumpf approach and compare it with values derived from shear experiments.

A single fitted value of the unknown capillary bridge gap is able to provide quantitative agreement for experiments with highly humid air. Model estimation indicates that water mainly condenses on rough surfaces of the particles and only a small portion of this condensed humidity contributes to change the powder flow properties in interparticle capillary bridges.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

POWDER FLOW AND DUST EMISSIONS

R. Ansart, A. de Ryck and J. A. Dodds,

Centre RAPSODEE-UMR CNRS 2392, Ecole des Mines d’Albi-Carmaux

F-81000 Albi, France

The handling of bulk materials in free streams of particles is a source of dust emission – Abstract during the fall or at the impact on a pile, if fines are present. To quantify it, we discuss the physics of the phenomenon and focus on the role of air entrainment.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

WEAR OF STRAIGHT PIPELINE IN PNEUMATIC CONVEYING SYSTEMS

V. K. Agarwal (1) and D. Mills (2)

1. Indian Institute of Technology

New Delhi, India

2. Pneumatic Conveying Consultant

Garelochead, UK

Abstract

The wear of bends in pneumatic conveying system pipelines is a topic that has been given much consideration in technical papers. Bends, of course, can fail in a matter of hours if conveying conditions or bend materials are inappropriate for the duty. Straight pipeline, however, is also susceptible to wear, and particularly so in sections following a bend. The authors have both undertaken research into these problems and in this paper they combine their findings and examine the influence of many of the parameters that they have investigated.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

DEVELOPMENT OF AN EROSION TESTER

- SOME THEORETICAL & EXPERIMENTAL ASPECTS

M. Wolf (1), C. Ratnayake (2), G.G. Enstad (2), B.K. Datta (3), P. A. Amundsen (4), W. Schubert (5)

1. MCE Industrietechnik Salzburg GmbH & Co, Salzburg, Austria

2. Dept. of Powder Science & Technology (POSTEC), Telemark Technical R & D Centre (Tel-tek),

Porsgrunn, Norway

3. Aker Kværner Subsea AS, Fornebu, Norway

4. Dept. of Mathematics and Natural Science, University of Stavanger, Norway

5. Faculty of Process and Chemical Engineering, University of Applied Sciences, Mannheim, Germany

Abstract

In pneumatic conveying plants, wear has been identified as one of their major drawbacks. When a system is running in dilute phase mode, wear can be very effective, lead to unplanned maintenance due to leakage of pipes etc, discharge of bulk material to the

surroundings with associated occupational hygiene problems and problems caused by contamination of their transported material by eroded particles. Particularly in oil and gas industry, this phenomenon has been recognised as a major problem for its effective operation.

Even though quite a lot of scientific investigations have been carried out on wear in industrial pneumatic conveying systems, the problem is still with us, because the basic mechanisms of wear are only partly understood. In an early investigation [1], some weaknesses of currently used measurement techniques were identified and a novel method to measure and predict the erosion of a pneumatic conveying pipeline system was proposed, as an on-line measurement technique.

This paper briefs the development of an erosion tester based on those proposals, together with some theoretical and practical problems involved with it. In addition, some observations made during the test using the newly developed erosion tester are also presented.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

WEAR TESTING OF POLYMERS IN PNEUMATIC CONVEYING SYSTEMS

Hans Schneider, Harald Wilms

Zeppelin Silos & Systems GmbH, Friedrichshafen, Germany

Abstract

Polymer pellets generate fines and streamers in dilute-phase pneumatic conveying systems. Fines generation depends on many parameters, which make comparison of industrial data and prediction for new systems difficult. In order to predict fines generation levels in pneumatic conveying systems, Zeppelin has installed in its test facility a conveying system dedicated for running wear tests under defined conditions. A respective test procedure has been defined. Conveying tests with numerous polymers have been performed in the meantime and quantitative results from this test facility are presented. A database is being built up for different polymers.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

REDUCING DUST EMISSIONS FROM FALLING BULK SOLIDS BY WATER SPRAYING - DEVELOPMENT A SUITABLE MODEL EQUATION

W. Höflinger*, P. Grundnig, G. Mauschitz, J.Gao

Vienna University of Technology, Institute of Chemical Engineering,

Getreidemarkt 9, A-1060 Vienna;

ABSTRACT

One of the main origins of fugitive dust emission arises from bulk handling in quarries or mines, in particular, from bulk materials falling from a hopper or a conveyor belt. Waterspraying systems, using two-phase nozzles, are one of the methods to suppress such dust emission. In a laboratory bulk falling experimental apparatus, where in the enclosed box the spraying nozzle is situated, the generated dust is sucked off and the PM10 dust concentration were measured for different water flows and different nozzle positions. In order to develop a design method for the spraying device, a model was developed, by which the water flow consumption together with the relative humidity of the sucked- in air can be related to the reduction of PM10 dust emission. This model was developed in analogy to a deep bed filtration model, where the deep bed filter layer has a similar function like the droplet swarm of the spraying nozzle for the particle retention. This model can be used to clear-up in more

detail the responsible physical separation mechanism and will led further to an optimal design of the spraying device.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

WATER AVAILABLE FOR RECYCLING AFTER THE PLACEMENT OF DENSE PHASE FLY ASH SLURRIES

T.F., Bunn, M.G., Jones, C.A., Wheeler

Centre for Bulk Solids & Particulate Technologies, Faculty of Engineering and Built

Environment, The University of Newcastle, Australia

Abstract

The amount of water that is available for recycling after the placement of Dense Phase Fly Ash Slurries is dependent on the Cw of the placed slurry, the packing density of the fly ash particles and the Particle Size Distribution of the original fly ash. This paper examines the maximum amount of water that is available for recycling from a range of Dense Phase Fly Ash Slurries.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

PIPE STABILITY IN SILOS

J. Schwedes x) , M. Morgeneyerxx ), A. Cannavacciuoloxxx) , T. Ittershagenx) and A. Kwade x)

x) Technical University Braunschweig (Germany); xx) Universit de

Compiegne (France); xxx) Universit di Salerno (Italy)

Abstract

Stable pipes can be formed in funnel flow silos, when the strength of the stored bulk solid exceeds the circumferential stress in the surface of the formed pipe. Above a critical pipe diameter the pipe is not stable anymore. To predict the critical pipe diameter the strength of the stored bulk solid has to be known. Two design criteria exist: in the older one (Jenike 1961 [1]) a passive state of stress is assumed to prevail close to the silo outlet; in the newer one (first Johanson 1969 [2]) an active state of stress is assumed. The first criterion often leads to a design on the unsafe side, while the newer one can lead to a tremendous overdesign. Reason for this overdesign is the anisotropic behaviour of bulk solids being not considered in Johanson´s criterion. Experiments in a silo centrifuge have shown that both criteria lead to a safe and reliable design: Applying the older Jenike approach it has to be

guaranteed by an early partial discharge that a passive state of stress really exists. Applying the other approach with the active state of stress the anisotropic behaviour has to be considered.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

INVESTIGATION OF THE ANISOTROPIC BEHAVIOUR OF BULK SOLIDS

T. Ittershagen, J. Schwedes and A. Kwade

Institute for Particle Technology, TU Braunschweig

Braunschweig, GERMANY

Abstract

The anisotropic material behaviour is a characteristic of bulk solids. Prior research work proved that the measured unconfined yield strength of cohesive bulk solids is lower when the direction of the collapsing stress and the consolidation stress do not coincide. The anisotropic behaviour is significant for many applications in the handling of bulk solids, for instance pelleting or silo design. A new powder tester has been developed to measure the unconfined yield strength in the uniaxial direction, which provides consolidation and collapse stresses in the same direction, as well as the anisotropic unconfined yield strength in the biaxial direction, which means consolidation and collapse stresses are in orthogonal directions. The consolidation stress is applied through two

movable side walls in the horizontal direction, allowing measurement of the anisotropic unconfined yield strength, and in the vertical direction for measuring the normal unconfined yield strength. The friction between the walls and the bulk solid is minimized by the use of rubber membranes which deform uniformly with the tested bulk sample. After the consolidation procedure, all side walls are

removed. Thereafter, the free-standing sample can be stressed by a piston in the vertical direction until failure occurs at the specific unconfined failure stress. The uniaxial and the anisotropic unconfined yield strengths have been measured for a limestone powder test-material at different consolidation stresses. Design of the tester as well as first experimental results are presented.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

PIPE COLLAPSE IN THE AERATED SILO DISCHARGE OF COHESIVE POWDERS

Antonio Cannavacciuolo1,2, Diego Barletta1, Giorgio Dons1, Giovanna Ferrari1, Joerg Schwedes2 and Massimo Poletto1

1. Department of Chemical and Food Engineering, University of Salerno

Via Ponte don Melillo, I-84084 Fisciano (SA), Italy.

2. Institute for Particle Technology, Technical University of Braunschweig

Volkmaroder Straße 5, 38104 Braunschweig, Germany.

Abstract

The limiting aeration condition necessary to produce the collapse of established pipes is evaluated in a flat bottomed aerated silo. The main parameters tested are the powders properties and the width of the aeration pad at the silo bottom. The measured quantities are the aeration rates and the corresponding size of the pipe. The gas pressure gradient close to the pipe is estimated from the

numerical solution of the air flow field in the bulk solids in the hypothesis of Darcy flow regime. The powder permeability necessary for this calculation is estimated by fluidization experiments. The hoop stress evaluated according to Johanson [4] is in good agreement with the unconfined yield strength of the powder provided that the contribution of aeration to powder consolidation during pipe formation is properly accounted for.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

Spore inactivation and quality of paprik a powder heated by near-infrared radiation

N. Staacka,b, L. Ahrn a, E. Borcha, D. Knorrb

a SIK – The Swedish Institute for Food and Biotechnology, P.O. Box 5401, SE-402 29 Göteborg, Sweden

b University of Technology of Berlin, Königin-Luise-Strasse 22, D-14195 Berlin, Germany

Objective

Dried powders, such as spices, may contain high microbial counts, particularly bacterial spores known for their high heat resistance and good survival capability. Although these spores do not germinate in the powders, when added to high-moisture foods a suitable environment is given for microbial growth. In order to reduce the microbiological contamination and inactivate food altering enzymes many processes expose the powder to a moisture environment during the heat treatment.

This paper used infrared (IR) heating on decontaminating food powders. Infrared radiation (IR) has the advantage of fast and effective heating of food material with a product specific penetration depth. A disadvantage during IR heating is that water evaporates from surfaces due to high temperatures. A process for decontamination of paprika powder using near-IR heating was tested, by (a) developing and testing a closed sample holder to avoid the undesired water evaporation from the powder surface; (b) developing a IR heating process based on variable near-infrared to avoid overheating; and c) studying the effects of product temperature and pH on reduction of spores of Bacillus cereus, and aw and colour of paprika (model material) after IR heating.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ANALYSIS OF GRANULE BREAKAGE IN A ROTARY MIXING DRUM:

EXPERIMENTAL STUDY AND DISTINCT ELEMENT ANALYSIS

H. Ahmadian, M. Eggert, A. Hassanpour, M. Ghadiri

Institute of Particle Science and Engineering

University of Leeds, Leeds LS2 9JT, UK

Abstract

Rotary drums are commonly used in particulate solid industries for mixing, coating and reactions. The process is often accompanied by undesired breakage of granules. For this reason, they are sometimes used as an attrition testing device. In this work, the attrition of three types of granules in a rotary drum is analysed. The granules have been produced by fluid-bed coating (size 300 to 1000 m), high shear granulation (size 300 to 1000 m) and extrusion (size 500 to 1000 m).

The rotary drum has an internal diameter of 0.39 m and a single baffle. Attrition tests are conducted at 18, 35 and 52 rpm for 4000 cycles. The extent of breakage is quantified by sieving out fine debris which is two sieve sizes smaller than the feed particles. To relate the extent of breakage in the drum to granule characteristics, single granule impact tests are performed on one type of granule at several velocities. The effects of particle size and impact velocity are analysed and a power-law

relationship is found between impact velocity and single granule breakage. This information is used to simulate granule breakage in a rotary drum by Distinct Element Method (DEM). The drum is simulated for 5 rotations at the rotational speeds stated above and the breakage rate per rotation is compared to experimental results obtained.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

INVESTIGATION ON THE CRYSTALLIZATION KINETICS OF DEXTROSE MONOHYDRATE USING IN-SITU PARTICLE SIZE AND SUPERSATURATION MONITORING

Abhay Markande 1) 3), Amale Nezzal2), John Fitzpatrick, 1), Luc Aerts3)

1) Department of Process and Chemical Engineering, University College Cork, Ireland

2) Nezzal Powder consulting, 55 rue Bermond, 81000 Albi, France

3) Syral, Aalst, Belgium

Abstract

The prediction of the performance of an industrial scale production of dextrose monohydrate is a difficult task because of various phenomena, nucleation, growth, breakage and aggregation, taking place simultaneously. At industrial scale crystallization, the main challenge to process engineers is to predict the influence of change in operating conditions on the process behavior such as final crystal size distribution, process productivity etc. For reliable prediction of final production performance, it is

important to investigate the basic nucleation and growth mechanism dominating the crystallization

process.

In the present work, a seeded batch cooling crystallization is used to study dextrose monohydrate crystallization. Experiments are conducted under the parameters like seed mass % and cooling strategy. These parameters are varied in accordance with industrial scale process. Experimental results are analysed to evaluate the kinetics constants from the growth and nucleation power law functions with

supersaturation. The seed mass and cooling profile have been particularly focused to determine the effect of secondary nucleation and crystal growth rate on the final crystal size distribution, the course of supersaturation and productivity. For this purpose two in situ techniques: Lasentec® Focused Beam Reflectance Measurement (FBRM) and an in line process refractometer for monitoring aqueous

crystallization of dextrose monohydrate is used. FBRM provides in-situ information of crystal size and particle concentration in the form of a chord length distribution. The process refractometer used to measures concentration evolution in the mother liquor during the crystallization process.

The results showed the change in crystal size distribution and the productivity of the crystallization considering the effect of change in supersaturation, seed characteristics and the cooling stratergy.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

AN ANALYSIS OF A SIMPLE TEST DEVICE FOR TRIBO-CHARGING OF BULK POWDERS

Enes upuk1, Ali Hassanpour1, Christian Seiler2 and Mojtaba Ghadiri1

1. Institute of Particle Science and Engineering, University of Leeds, Leeds LS2 9JT, UK

2. Merck Sharpe & Dohme Ltd., Hoddesdon, Hertfordshire H11 9BU, UK

Abstract

A simple device for characterisation of the tribo-charging propensity of powders has been developed at the University of Leeds, where a small amount of powder is placed inside a 10 ml container, which is shaken by reciprocal strokes in a horizontal direction. Several containers with

different materials have been made: stainless steel, polytetrafluoroethylene (PTFE) and glass. The charge on the powder is measured using a Faraday cup connected to an electrometer. The charge is measured before and after the shaking process.

The main objective of this work is to analyse the operation of this simple test device by investigating the behaviour of -lactose monohydrate, hydroxy propyl cellulose (HPC) and a 50:50 binary mixture (by mass) of these two powders with various surfaces that are most commonly used

in the pharmaceutical industry. The experiments are carried out in controlled environmental conditions and using different shaking times together with different shaking frequencies of 10, 20 and 30 Hz.

The experimental results show that a-lactose monohydrate and HPC particles have the highest magnitude of charge at 20 Hz frequency against all surfaces tested. This is surprising, as it is intuitively expected that higher charges should be produced at 30 Hz, given other conditions. The

dynamic movement of particles within a shaking container vary with frequency. This results in a varied amount of particle-wall contacts which affects particle charging.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

EFFECT OF ELECTROSTATIC CHARGE ON PARTICLE MIXING BEHAVIOUR IN AGITATION SYSTEM BY PARALLEL DISCRETE ELEMENT METHOD

Hiroshi Mio1,2, Ryohei Higuchi3, Atsuko Shimosaka3, Yoshiyuki Shirakawa3 and Jusuke Hidaka3

1. Research Center for Advanced Science and Technology, Doshisha University

Kyotanabe, JAPAN

2. Kyoto Fine Particle Technology, Keihanna Interaction Plaza Inc.

Kyoto, JAPAN

3. Department of Chemical Engineering and Materials Science, Doshisha University

Kyotanabe, JAPAN.

Abstract

The objective of this paper is to analyse the particle mixing behaviour in twocomponent electrophotographic system by using parallel Discrete Element Method. The effect of the electrostatic charge on the mixing behaviour was discussed. The toner particles were segregated near the outer wall, when the adhesion force was not considered in the calculation. On the other hand, the toner particles were located between the carrier particles when the toner particles had 15 µC/g in charge and the adhesion force was considered between particles. The number of contact between particles increased under considering the adhesion force, however, the number of new contacts between them decreased, if particles were adhesive. Thus, the most of toner particles are stuck to the surface of carrier particles, and they are moving together. It seems that the toner charge would be saturated in this condition because of the reduction of new contact.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ELECTROSTATIC CHARGING OF POWDER IN PNEUMATIC CONVEYING AND APLICABILITY OF GENERATED ELECTRIC SIGNALS

K.Azin1 , G.G.Enstad1,2 and M.Waskaas2

1. Telemark Technological R & D Centre

Porsgrunn, NORWAY

2. Telemark University College

Porsgrunn, NORWAY

Abstract

In handling and storage of particulate materials people may encounter flow problems attributed to static electric charge generation. The phenomenon of electrostatic charging of bulk particulate materials is also often experienced in pneumatic transport of particulate solids. Such charging may cause explosions or severe discharges of electricity which may be dangerous for the operators nearby. Enhanced understanding of electrostatic charging mechanisms during handling of particulate materials will help industry to avoid dangers associated with this phenomenon. This new knowledge may also lead to development of techniques for measurement of flow related properties like mass flow rate and particle velocity in pneumatic conveyig. This article will have a look at the latest development for understatnding and use of electrostatic charging of powder in pneumatic

transport. The idea of using correlation between electrostatic signals and other multiphase flow properties and a test rig built for this purpose will be discussed briefly as well.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

Opportunities with Transformative Research in Pneumatic Conveying

George E. Klinzing

University of Pittsburgh

Abstract

An attempt is made to call attention to the need to be more risky and exploratory in our research scheme when studying pneumatic conveying. The term transformative research is the strategy’s title which has been adopted by many of the funding agencies in the world. Significant resources have been spent to provide new information but mostly in an incremental fashion rather than making large gains in our knowledge. This paper reviews what can be considered as transformative advances in the field of pneumatic conveying over the past sixty + years and projects what avenues and areas we can look to for future advancements.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ADVANTAGES OF HIGH-PRESSURE DILUTE-PHASE CONVEYING SYSTEMS

H. Wilms

Zeppelin Silos & Systems GmbH

Friedrichshafen, GERMANY

Abstract

Numerous applications, especially in the polymer industry, require closed-loop conveying systems operated under nitrogen. The return gas system comprising return gas line, filter, cooler consumes a substantial portion of the available pressure. An alternative to low-pressure conveying systems operated by blowers are high-pressure dilute-phase conveying systems using a screw

compressor, allowing higher solids-to-air ratios. Comparative calculations of a case study reveal the different options and clearly reveal the advantages with respect to investment and operating cost of using high-pressure dilute-phase conveying systems for closed-loop applications.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

CHANGES IN PARTICLE SIZE AND SHAPE IN PNEUMATIC CONVEYING OF DEXTROSE

C. Arakaki1, C. Ratnayake1 and G.G. Enstad1,2

1. Telemark Technological R & D Centre

Porsgrunn, NORWAY

2. Telemark University College

Porsgrunn, NORWAY

Abstract

During pneumatic conveying of particulate materials, changes in the size and shape of the individual particles can be observed. These changes can have a great impact in the bulk powder and affect its flow properties in the pipelines and can be wanted or unwanted according to the whole process chain and final use of the powder. In this investigation, dextrose monohydrate particles

were pneumatically conveyed repetitively and the size and shape of the particles were characterized by a semi-automatic image analysis method; qualitatively by observing micrographs and quantitatively by using statistical diameters and two shape factors. The mass flow rate of the pneumatic conveying tests was not affected by changes in size and shape of the dextrose particles.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

MASS FLOW RATE MEASUREMENT IN A PNEUMATIC CONVEYOR USING A SYSTEM IDENTIFICATION MODELLING APPROACH

1 Ruscio . D . D & 2 Ratnayake . C , 2 Arakaki . C , 1 Sæther . A

1. Telemark University College

Porsgrunn, NORWAY.

2. Telemark Technological R & D Centre

Porsgrunn, NORWAY

Abstract

Accurate measurements of solids flow rate in pneumatic conveying systems has been a need for the different industries in which these systems are used. In this study, a system identification approach, which is termed as the Deterministic Stochastic Realization (DSR) method is used to obtain a model on state space form. The selection of inputs to the system identification model is based on conservation of energy related to the Bernoulli effect. Under this investigation,

attempts were made to predict the mass flow rate of conveying solids in real time, by using pressure data obtained from 3 different pressure sensors located on the conveying line, blow tank pressure and inlet air volume flow rate. To evaluate the performance of the DSR model, the results were compared with one published method based on a scaling up technique of pneumatic conveying [1]. The Root Mean Squared Error of Prediction (RMSEP) of the cumulative mass of transported solids

as a percentage of the total conveyed mass using the system identification model was between 1.3- 5.8%.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

NUMERICAL INVESTIGATIONS FOR CONTINUOUS USE OF GRAVITY SILO MIXERS TO SMOOTH PERIODICAL INLET FLUCTUATIONS

H. Dauth1, K. Sommer1

1. Technische Universität München, Center of Life Sciences Weihenstephan, Lehrstuhl für

Maschinen- und Apparatekunde, GERMANY

Abstract

With a mathematical model principle effects of silo mixing processes can be simulated. The model is a simulation of a circulating mixing silo. The fundamental idea is to split the silo into a number of parallel individual silos (or cells), each of which is subject to the same flow conditions. Each cell has a distinct volume Vi and residence time ti that correspond to the different residence time characteristic of the process. The residence time distribution of the silo model is therefore the only necessary parameter for modeling the process. This parameter is defined by the geometry of the silo and the existing fixed mountings.

Founded on a basis of very good agreement between the simulation predictions and experimental mixing results for a lot of trials, further simulations were conducted using only different ideal residence time distributions (normal-distribution, log-distribution, linear-distribution, bimodaldistribution) as inputs. The theoretical investigations are focused on the outlet concentration of the silo, the standard deviation at the silo outlet and the standard deviation for the entire silo related to the known mixing ratio. The major results will be discussed.

Further theoretical investigations are aimed at simulating changing load conditions, in order to detect the influence of these changes in the blending results. Based on these results, further calculations for the periodical inlet fluctuations (e.g. rectangular or sinusoidal concentration fluctuation) of a component were carried out. The aim is to estimate among which conditions a mixing silo can be used for continuous operation.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

CFD VISUALISATION OF A PNEUMATIC CONVEYING PASSIVE BY-PASS LINE

D. McGlinchey and A. Cowell

School of Engineering and Computing

Glasgow Caledonian University

Glasgow G4 0BA

UK

Abstract

A computational fluid dynamic transient analysis of the operation of a passive by-pass system in clearing a pneumatic conveying pipeline blockage was undertaken and in this paper results on the change of volume fraction and gas velocity are presented. A section of pneumatic conveying pipeline with a passive by-pass line was modelled and meshed using GAMBIT. The CFD analysis performed using FLUENT was based on an Euler - Euler approach with the solids being modelled with the granular kinetic theory. A stationary plug of material was placed in the line at a location where the “inlet” to the bypass line was clear and the “outlet” halfway along the plug. The gas flow and details of plug – gas interaction are discussed.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

THE APPLICATION OF WAVELET TRANSFORMS TO MANY-BODY PARTICLE INTERACTIONS

N.Meejun1, A.C.Skeldon2, U.Tüzün 1, C.O’Sullivan 3 and G.Cheung3

1. Chemical and Process Enginerring, Faculty of Engineering and Physical Sciences,

University of Surrey UK

2. Department of Mathematics, Faculty of Engineering and Physical Sciences,

University of Surrey UK

3. Department of Civil and Environmental Engineering, Imperial College, London, UK

Abstract

The application of wavelet transforms to data sets which are results of a discrete element simulation of biaxial and triaxial compression test are presented. The multi-resolution analysis of stress ratio, porosity and coordination number can reveal distinct localizations developed in the specimen as the compression of the sample is underway. We show how the wavelet technique may be used to find the strain scales on which critical events occur and to identify regions both in space and in strain when particles in the sample undergo significant activity.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

HYDRODYNAMICS BEHAVIOR OF BINARY MIXTURES OF BIOMASS AND ALUMINA IN A GAS-FLUIDIZED BED

K. Tannous1, E. Olivares-Gmez2 and A.L.B. Sauvanel3

1. School of Chemical Engineering, State University of Campinas

Campinas, BRAZIL

2. NEST, Federal University of Itajub

Itajub, BRAZIL

3. Energetic Efficiency Center, University of Oriente

Santiago de Cuba, CUBA

Abstract

The aim of this work is to study the hydrodynamics behavior of binary mixtures between biomass (rice husk) and alumina in a gas-fluidized bed. Experiments were carried out in a 0.092m ID acrylic column. The solid particles were classified as B and D concerning Geldart´s classification. The percentages of rice husk that were studied were from 2.5 to 15 by weight. The particle size ratios of these binaries varied from 5 to 13, while the density kept the buoyed-density ratio equal to 2.4. Three characteristic velocities have been identified: the initial fluidization velocities (Ufi), the apparent fluidization velocity (Ufa) and the complete fluidization velocity (Ufc). For fine particles, these velocities and apparent fluidization porosity (fa) are practically independent of the weight ratio for less than 10 %. Experimental data of Ufa were compared with correlations known from the literature.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

EFFECT OF SIZE RATIO ON THE BEHAVIOUR OF PARTICLES EMBEDDED IN A BED OF GLASS BEADS SUBJECTED TO SHEARING: EXPERIMENTAL AND DEM ANALYSIS

H. Ahmadian, A. Hassanpour and M. Ghadiri

Institute of Particle Science and Engineering

University of Leeds, Leeds LS2 9JT, UK

Abstract

The stress nature and breakage behaviour of a particle inclusion embedded in a matrix of particles subjected to shearing (normal pressure and strain rate of 20 kPa and 10 to 13 s-1, respectively) is investigated. In previous studies the size ratios (ratio of the diameter of inclusion to diameter of surrounding particles) of 3 to 15, more applicable to the granulation process, were investigated. In this work, the effect of lower size ratios, ranging from 0.71 to 2.5, on the stress ratio (ratio of deviatoric stress to hydrostatic stress) are investigated by Distinct Element Method (DEM) simulations. It is shown that as the size ratio is decreased below 2.5, the number of contacts

around the embedded particle decreases and the maximum stress ratio drastically increases, promoting particle breakage. This trend is consistent with experimental observations, where the granule breakage increases with a decrease in size ratio.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

PRODUCTION OF SOLID-PHASE BIOCATALYST BY IMMOBILIZATION OF –GALACTOSIDASE ONTO MICRO-SIZED CHITOSAN PARTICLES

E. Biro1,2, A. Sz.-Nemeth1, C. Sisak1, T. Feczko1,3, J. Gyenis1

1. University of Pannonia, Faculty of Information Technology, Research Institute of Chemical and

Process Engineering, 10 Egyetem Street, biro@mukki.richem.hu,

HU-8200 Veszprem, HUNGARY

2. Delft University of Technology, Department of Chemical Technology, Particle Technology

Group, 136 Julianalaan,

NL-2628 BL Delft, THE NETHERLANDS

3. Hungarian Academy of Science, Chemical Research Centre, Institute of Materials and

Environmental Chemistry, 59-67 Pusztaszeri Street,

HU-1025 Budapest, HUNGARY

Abstract

Chitosan microparticles have been prepared by emulsion cross-linking method. Glutaraldehyde was used as cross-linking agent, which allows covalent attachment of the enzyme. A wide range of particle size could be produced using the emulsion cross-linking method.

Practically, any desired size between 20 and 500 m could be reached by properly choosing the type and concentration of surfactant.

The obtained microparticles proved to be suitable for immobilization of -galactosidase. -Galactosidase enzyme was immobilized onto microparticles to obtain solid-phase biocatalyst. The biocatalysts fixed on microspheres were stable at 4ºC for 3. The immobilized -galactosidase proved to be very stable and operated with almost the same yields throughout the performed 10 runs.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ENERGETIC ANALYSIS OF POWDER COMPACTION

M. Röck1, T. Ittershagen2, A. Kwade2 and J. Schwedes2

1. Evonik Degussa GmbH, Process Technology & Engineering, Particle Processing

Hanau-Wolfgang, GERMANY

2. Institute for Particle Technology, TU Braunschweig

Braunschweig, GERMANY

Abstract

Compaction of powders is of interest from both industrial and academic points of view. The compaction behaviour comprises the interaction of bulk density with porosity and compaction stress and is important to characterize bulk solids. In general the compaction behaviour of a powder is plotted using a porosity-stress diagram, referred to as a compaction curve. The aim of this paper is to present compaction curves obtained for different compaction procedures using the True Biaxial Shear Tester. The True Biaxial Shear Tester allows the investigation of uni-axial and bia-xial compaction procedures and additionally a stair-like compaction procedure with uni-axial compaction in the x-direction followed by uni-axial compaction in the y-direction. These compaction procedures are analysed according to the energy input required to reach the final porosity. This approach allows the energetic and thus the economic optimization of the compaction process of powders.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

AVALANCHING AND BREAKING OF ROTATING POWDER LAYERS:

A NEW DEVICE TO MEASURE COHESION

A. Castellanos

Faculty of Physics, University of Seville, Avda. Reina Mercedes s/n, 41012 Seville, Spain

Abstract

We study the effect of the combined action of centrifugal and gravitational forces on the avalanching and breaking of vertical and horizontal layers made of cohesive powders. Because the layers are thin we may safely assume uniformity of the material properties across them. In both cases, at a critical value of the angular velocity the shear stresses are large enough to drive material avalanches. The analysis of the vertical layer is based on the Coulomb method of wedge, and allow us to determine the cohesion and angle of internal friction of the powder.

For the analysis of the horizontal spinning disk we have devised a simple physical model, that allows us to obtain the value of the tensile strength. The results show that both cohesion and tensile strength are of the same order of magnitude, thus indicating that the yield locus is curved to the left of the origin. Since the boundary and initial conditions are better controlled for vertical layers, we have developed a novel device [1] enabling us to measure the angle of internal friction and cohesion of loosely consolidated cohesive granular materials. As further checks we have estimated experimentally the angle of internal friction and cohesion of powder samples

compacted by previous vertical vibration. These parameters have been also measured using an independent standard technique (automated Schulze ring shear tester) and the values obtained agree within the experimental indeterminacy with the values obtained from our powder tester.

Some advantages of the new powder tester are: i) it needs a quite reduced mass of material for testing, ii) the test is of short duration, typically of the order of minutes, iv) the shear on the sample is not induced by external mechanical parts, which avoids problems such as wall sliding, v) the fracture inside the sample is clearly identified by direct visualization of the shearing process, and, vi) it allows for testing at very small consolidations.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

ENERGY ABSORPTION AT SHEAR FLOW AND COMPRESSION OF DRY ULTRAFINE POWDERS

Jürgen Tomas

Mechanical Process Engineering, The Otto-von-Guericke-University

Universitätsplatz 2, D – 39 106 Magdeburg, Germany

Abstract

For the non-rapid frictional shear flow in powder handling practice, the fundamentals of cohesive powder consolidation and flow are briefly explained by combination of particle micromechanics and powder continuum mechanics. With this physical basis, incipient powder consolidation, yield and cohesive steady-state flow are explained. These yield loci are completely described only with three material parameters, i.e., angle of internal friction, stationary angle of internal friction, isostatic tensile strength of an unconsolidated powder and the influence of averaged pressure during pre-consolidation. Next, the physical basis of the enormous compressibility of cohesive powders is explained by compression rate and compression function. This powder compression behaviour is classified by a compressibility index n (with 0 ≤ n < 1) as an additional constitutive parameter. As consequence of poor flowability and large compressibility, ultrafine powders can absorb large amounts of energy during compression and shear flow. Exemplary, the flow properties of an ultrafine limestone powder are shown. These constitutive models are used to evaluate shear test results for apparatus design to ensure reliable powder flow. Finally, conclusions are drawn concerning particle stressing, powder handling and product quality assessment in processing industries.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■

MICROMECHANICS OF ULTRAFINE PARTICLE ADHESION – CONTACT MODELS

Jürgen Tomas

Mechanical Process Engineering, The Otto-von-Guericke-University

Universitätsplatz 2, D – 39 106 Magdeburg, Germany

Abstract

Dry, ultrafine, cohesive and compressible powders (particle size d < 10 µm) show a wide variety of typical flow problems that cause insufficient apparatus and system reliability of processing plants. Thus, it is very essential to understand the fundamentals of particle adhesion with respect to product quality assessment and process performance in particle technology.

Comprehensive models are shown that describe the elastic-plastic force-displacement and frictional moment-angle behaviour of adhesive contacts of isotropic smooth spheres. Using the model stiff particles with soft contacts, a sphere-sphere interaction of van der Waals forces without any contact deformation describes the stiff attractive term. The soft micro-contact response generates a flattened contact, i.e. plate-plate interaction, and increasing adhesion. These increasing adhesion forces between particles directly depend on this frozen irreversible deformation. Thus, the adhesion force is found to be load dependent. It essentially contribute to the tangential forces in an elastic-plastic frictional contact with partially sticking within the contact plane and microslip. The load dependent rolling resistance and torque of mobilized frictional contact rotation (spin) is also shown.

You can order the electronic version of the Procceedings for Euro 100 at:

http://www.relpowflo.no/ ■