Showing papers by "Kenneth Williams published in 2008"

Dense Phase Pneumatic Conveying of Powders: Design Aspects and Phenomena

Abstract: ...............................................................................................................1 CHAPTER 1: INTRODUCTION................................................................................2 1.1 Modes of Flow .........................................................................................................3 1.1.1 Plug flow.........................................................................................................4 1.1.2 Fluidised dense phase flow .............................................................................6 1.2 Thesis Overview ......................................................................................................8 1.2.1 Mode of flow...................................................................................................8 1.2.2 Solids friction..................................................................................................9 1.2.3 Solids velocity...............................................................................................11 CHAPTER 2: PREDICTING CONVEYING MODES OF FLOW.......................13 2.1 Bulk Material Parameters.......................................................................................14 2.1.1 Basic parameters ...........................................................................................14 2.1.1.1 particle size distribution.......................................................................14 2.1.1.2 particle density .....................................................................................14 2.1.1.3 bulk density..........................................................................................15 2.1.2 Air-particle parameters .................................................................................15 2.1.2.1 permeability .........................................................................................16 2.1.2.2 steady state fluidisation pressure .........................................................16 2.1.2.3 de-aeration............................................................................................16 2.2 Mode of Flow Data ................................................................................................17 2.3 Predictive Diagrams...............................................................................................21 2.3.1 Basic bulk material diagrams........................................................................21 2.3.1.1 Geldart’s fluidisation diagram .............................................................23 Dense Phase Pneumatic Conveying of Powders: Design Aspects and Phenomena v 2.3.1.2 Molerus’s fluidisation diagram ............................................................27 2.3.1.3 Dixon’s slugging diagram....................................................................31 2.3.1.4 Pan’s pneumatic conveying predictive diagram ..................................34 2.3.2 Air-particle bulk material diagrams ..............................................................35 2.3.2.1 Mainwaring and Reed diagram............................................................36 2.3.2.2 Jones diagram.......................................................................................39 2.3.2.3 Chambers et al parameter.....................................................................40 2.3.2.4 Fargette et al parameter........................................................................42 2.3.2.5 Sanchez et al diagram ..........................................................................44 2.4 Proposed Mode of Flow Diagram..........................................................................46 2.5 Summary ................................................................................................................47 CHAPTER 3: EXPERIMENTAL PROGRAM AND DATA.................................49 3.1 Bulk Material Testing Methods .............................................................................49 3.1.1 Basic parameter test methods........................................................................49 3.1.2 Air-particle parameter test methods..............................................................51 3.1.3 Flow property tests........................................................................................53 3.2 Bulk Material Data.................................................................................................54 3.2.1 Cement Meal .................................................................................................55 3.2.2 Flyash............................................................................................................57 3.2.3 Alumina.........................................................................................................59 3.3 Conveying Tests.....................................................................................................61 3.3.1 Feeding and receiving systems .....................................................................61 3.3.2 Calibration of instruments.............................................................................63 3.3.3 Air mass flow rate calibration.......................................................................65 Dense Phase Pneumatic Conveying of Powders: Design Aspects and Phenomena vi 3.3.4 Conveying pipeline configurations ...............................................................67 3.3.5 test procedure and analysis ...........................................................................71 3.3.5.1 test procedure .......................................................................................71 3.3.5.2 test analysis ..........................................................................................71 3.4 Jones Pneumatic Conveying Test Data [18] ..........................................................76 3.4.1 Pulverised Fuel Ash data sheet .....................................................................77 3.4.2 Democrat Flour .............................................................................................78 3.4.3 Iron Powder data sheet..................................................................................79 CHAPTER 4: SOLIDS FRICTION CORRELATIONS – REVIEW AND ANALYSIS .........................................................................................80 4.1 Current Pressure Models ........................................................................................81 4.1.1 Scale-up methods ..........................................................................................81 4.1.2 Empirical methods ........................................................................................82 4.2 Solids Friction and Two Phase Fluid Pressure Model ...........................................83 4.2.1 Air friction factors.........................................................................................83 4.2.2 Solids friction factors ....................................................................................84 4.2.3 Effect on pressure drop .................................................................................87 4.2.3.1 diameter scale-up analysis ...................................................................89 4.2.3.2 length scale-up analysis .......................................................................92 4.3 Comparison of Pressure Analysis with Experimental Tests ..................................95 CHAPTER 5: SOLIDS FRICTION – POWER LAW ..........................................100 5.1 Back Calculation of the Power Law ....................................................................100 5.1.1 Co-efficient and exponent behaviour..........................................................101 5.1.2 Scale-up behaviour......................................................................................107 5.1.2.1 pipeline length variations ...................................................................108 Dense Phase Pneumatic Conveying of Powders: Design Aspects and Phenomena vii 5.1.2.2 pipeline diameter variations ...............................................................113 5.1.3 Summary of power law back calculation....................................................118 5.2 Optimal Power Law Determination .....................................................................119 5.2.1 Empirical optimisation methods .................................................................119 Comparison of the optimal power law methods ...................................................124 5.2.2 Pressure drop prediction and bench scale based parameters.......................125 CHAPTER 6: NUMERICAL MODEL FOR SOLIDS VELOCITY...................130 6.1 Current modelling ................................................................................................131 6.2 The Initial Continuum Model Approach..............................................................131 6.2.1 Force equilibrium and conservation of mass ..............................................132 6.2.2 Force equilibrium equations........................................................................133 6.2.3 Conservation of mass ..................................................................................134 6.3 Pressure Drop.......................................................................................................134 6.4 Differential Equations ..........................................................................................134 6.5 Initial Conditions..................................................................................................135 6.6 Behaviour of the Non-Linear Differential Equations ..........................................136 6.7 Comparison of Continuum Model to Conveying Tests .......................................138 6.7.1 Constant solids friction along pipeline..........................................