Dust Explosions: Course, Prevention, Protection (1989)

1 Introduction.- 2 Historical Review.- 2.1 Occurrence of Dust Explosions.- 2.2 The Nature of Dust Explosions.- 2.3 Apparatus for the Testing of Airborne Dusts.- 3 Dust as a Dispersed Substance.- 4 Material Safety Specifications.- 4.1 Preliminary Remarks.- 4.2 Material Safety Specifications of Dust Layers (G. Zwahlen).- 4.2.1 Flammability.- 4.2.2 Burning Behavior.- 4.2.2.1 Combustibility Test at Room Temperature.- 4.2.2.2 Combustibility Test at Elevated Temperature.- 4.2.2.3 Burning Rate Test.- 4.2.3 Deflagration.- 4.2.3.1 Screening Test for Deflagration.- 4.2.3.2 Laboratory Test for Deflagration.- 4.2.4 Smolder Temperature.- 4.2.4.1 Determination of the Smolder Temperature.- 4.2.5 Autoignition.- 4.2.5.1 Determination of the Relative Autoignition Temperature, as per Grewer.- 4.2.5.2 Hot Storage Test in the Wire Mesh Basket.- 4.2.6 Exothermic Decomposition.- 4.2.6.1 Determination of the Exothermic Decomposition Temperature in an Open Vessel, as per Lutolf.- 4.2.6.2 Determination of an Exothermic Decomposition in an Oven Purged with Nitrogen, as per Grewer.- 4.2.6.3 Differential Thermal Analysis.- 4.2.6.4 Determination of an Exothermic Decomposition Under Choked Heat Flow.- 4.2.7 Explosibility.- 4.2.7.1 Impact Sensitivity.- 4.2.7.2 Friction Sensitivity.- 4.2.7.3 Thermal Sensitivity.- 4.3 Material Safety Specifications for Dust Clouds Describing the Explosion Behavior.- 4.3.1 Combustible Dusts.- 4.3.1.1 Preliminary Remarks.- 4.3.1.2 Particle Size Distribution.- 4.3.1.3 Explosibility.- 4.3.1.4 Explosible Limits.- 4.3.1.5 Explosion Pressure Versus Explosion Violence.- 4.3.2 Flock.- 4.3.2.1 Preliminary Remarks.- 4.3.2.2 Explosible Limits.- 4.3.2.3 Explosion Pressure/Violence of Explosion.- 4.3.3 Hybrid Mixtures.- 4.3.3.1 Preliminary Remarks.- 4.3.3.2 Explosible Limits.- 4.3.3.3 Explosion Pressure /Violence of Explosion.- 4.3.4 Conclusions.- 4.4 Safety Characteristics of Airborne Dust Describing the Ignition Behavior.- 4.4.1 Minimum Ignition Energy.- 4.4.1.1 Preliminary Remarks.- 4.4.1.2 Apparatus for the Determination of the Minimum Ignition Energy.- 4.4.1.3 Ignition Behavior of Combustible Dusts.- 4.4.1.4 Ignition Behavior of Flock.- 4.4.1.5 Ignition Behavior of Hybrid Mixtures.- 4.4.1.6 Conclusions.- 4.4.2 Ignition Temperature.- 4.4.2.1 Preliminary Remarks.- 4.4.2.2 Apparatus for Temperature Determination.- 4.4.2.3 Ignition Effectiveness of a Glowing Coil.- 4.4.2.4 Conclusions.- 4.5 Safety Characteristics of Airborne Dusts Describing the Course of an Explosion in Pipelines.- 5 Protective Measures Against the Occurrence and Effects of Dust Explosions.- 5.1 Preliminary Remarks.- 5.2. Preventive Explosion Protection.- 5.2.1 Preliminary Remarks.- 5.2.2 Prevention of Explosible Dust/Air Mixtures.- 5.2.3 Prevention of Dust Explosions by Using Inert Matter.- 5.2.3.1 Admixture of Nitrogen.- 5.2.3.1.1 Preliminary Remarks.- 5.2.3.1.2 Combustible Dusts.- 5.2.3.1.3 Hybrid Mixtures.- 5.2.3.1.4 UseofVacuum.- 5.2.3.1.5 Admixture of Solids.- 5.2.4 Prevention of Effective Ignition Sources.- 5.2.4.1 Preliminary Remarks.- 5.2.4.2 Mechanically Generated Sparks.- 5.2.5 Hot Surfaces/Autoignition.- 5.2.6 Static Electricity.- 5.2.7 Conclusions.- 5.3 Explosion Protectio'n Through Design Measures.- 5.3.1 Preliminary Remarks.- 5.3.2 Explosion Pressure-resistant Design for the Maximum Explosion Pressure.- 5.3.2.1 Explosion Pressure-resistant Design.- 5.3.2.2 Explosion Pressure Shock-resistant Design.- 5.3.3 Explosion Pressure-resistant Design for a Reduced Maximum Explosion Pressure in Conjunction with Explosion Pressure Venting.- 5.3.3.1 Preliminary Remarks.- 5.3.3.2 Explosion Pressure Venting of Vessels.- 5.3.3.3 Explosion Pressure Venting of Elongated Vessels (Silos).- 5.3.3.4 Explosion Pressure Venting of Pipelines.- 5.3.4 Explosion-resistant Construction for Reduced Maximum Explosion Pressure in Conjunction with Explosion Suppression.- 5.3.5 Technical Diversion or Arresting of Explosions.- 5.3.5.1 Preliminary Remarks.- 5.3.5.2 Extinguishing Barrier.- 5.3.5.3 RotaryAir Locks (Rotary Valves).- 5.3.5.4 Rapid-Action Valves: Gate or Butterfly Type.- 5.3.5.5 Rapid-Action Valve: Float Type.- 5.3.5.6 Explosion Diverter.- 5.3.6 Conclusions.- 6 Concluding Remarks.- 7 Acknowledgements.- 8 Appendix.- 8.1 Explosion Pressure Venting.- 8.1.1 Vessel: Area Determination by Calculation or Nomogram.- 8.1.2 Elongated Vessels (Silos).- 9 References.- 10 Symbols and Abbreviations.- 11 Conversion Factors.- 12 Subject Index.