Explosions. w. Bartknecht. Course Prevention Protection. With 259 Figures, Some in Color and 34 Tables

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2 w. Bartknecht Explosions Course Prevention Protection With 259 Figures, Some in Color and 34 Tables Translation from the German by H. Burg and T. Almond Springer-Verlag Berlin Heidelberg New York 1981

3 Dr. Wolfgang Bartknecht c/o CIBA-GEIGY AG, Zentraler Sicherheitsdienst CH Basel Translators: H. Burg and T. Almond CIBA-GEIGY AG, CH-4002 Basel Revised translation of the second edition of "Explosionen. Ablauf und SchutzmaBnahmen" ISBN-13 : Springer-Verlag Berlin Heidelberg New York 1980 ISBN-13 : e-isbn -13 : DOl: / Library of Congress Cataloging in Publication Data. Bartknecht. Wolfgang. Explosions, course, prevention, protection. Rev. translation of the 2d ed. of Explosionen, Ablauf und SchutzmaBnabmen. Includes bibliographical references and index. 1. Explosions - Safety measures. 2. Explosions. I. Title. QD516.B ' ISBN-13 : (U.S.) This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. Under 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher. by Springer-Verlag Berlin Heidelberg 1981 Softcover reprint of the hardcover 1st edition 1981 The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Typesetting: Elsner & Behrens GmbH, Oftersheim. 2152/

4 Preface The hazards of explosions to human beings and to material values can hardly be overrated. These hazards are aggravated since powders and gas mixtures with a tendency to explode in general do not signal their inherent danger. But there is one powder whose name already indicates the hazard it represents. This substance is gunpowder. Whoever handles it is conscious of the danger to which he is exposed. He also knows that it is he, himself, who can trigger the explosion, he also can keep the hazard under control. In this respect, gunpowder has become one of the more harmless substances. Names and information indicating danger will create hazard consciousness in man which is a necessary condition for the institution of measures to protect himself and his material values. Gunpowder is only one of innumerable powders or dusts with an inherent dust explosion hazard. Technical development leads to an ever growing number of solids in the form of dust. Important properties of solids can only be put to use if they are present in the form of dusts. Only in the form of dust can flour be used for food, concrete for structures. No medicinal tablets could be made without pharmaceutical products in powder form. These are only a few examples of powders being of vital importance to men. Their number could be increased at will. Thus, products in the form of powders must be made, transported, stored in large numbers and also in large quantities. There is an important principle in powder technology: Dust creates finer dust. The finer the dust, the higher the explosion hazard. Dust is a particularly hazardous form of solid substances. By no means smaller are the hazards inherent to gaseous mixtures. To investigate, describe and master these hazards has been chosen by the author of this book as his task for life. The book consists of three main chapters in which are described the conditions for and the course of explosions, as well as the measures to prevent them or to protect against their effects. It covers the full span from scientific knowledge to the technical consequences to be derived therefrom. On the basis of comprehensive knowledge, a book

5 VI Preface has been written which presents in understandable form a field of technology of particular importance for technical development in general, that facilitates and thus also accelerates practical application. This book does more than just close a gap in technical literature. Primarily, it contributes to the technically safer handling of powders and gaseous substances. By means of this book, technology can be made a little safer, man can be given even better protection. For technical academies, this book illustrates that an important area of safety technology has been developed so far that it can now be taught and learnt. Heinz Brauer Professor of technology Technical University of Berlin

6 Contents Part I The Course of Explosions 1 Introduction Explosions in Closed Vessels Flammable Gases Explosion Limits Explosion Pressure - Violence of Explosion... 7 Flammable Gas (Vapour)/Air Mixtures Flammable Gas/Oxygen Mixtures Chlorine/Hydrogen Mixtures Combustible Dusts Preliminary Remarks Explosion Limits Explosion Pressure - Violence of Explosion Lowest Minimum Ignition Energy Hybrid Mixtures Preliminary Remarks Explosion Limits Explosion Pressure - Explosion Violence Lowest Minimum Ignition Energy Conclusions Explosions - Detonations in Pipelines Preliminary Remarks Flammable Gases Combustible Dusts Conclusions References... 70

7 VIII Contents Part II Protective Measures to Prevent Explosions or to Control Their Effects 1 Preliminary Remarks Measures to Prevent Explosions Inerting Preliminary Remarks Flammable Gases Combustible Dusts Conclusions Safety Measures Against the Effects of Explosions Within Enclosures or Rooms Preliminary Remarks Explosion Resistant Construction Pressure Vessels Pressure Shock Resistant Vessels Conclusions Explosion Relief Venting Preliminary Remarks Description of Relief Venting Relief Venting of Vessels Relief Venting of Rooms Design and Properties of Relief Venting Devices Preliminary Remarks Bursting Discs Bursting Discs Made of Brittle, Non-Deformable Material Bursting Discs Made of Defonnable Material Auxiliary Activation Bursting Discs Explosion Plates Self Closing Relief Devices Exposion Doors Spring Loaded Relief Devices Conclusions... " Sizing of Relief Areas Preliminary Remarks Flammable Gases Combustible Dusts Safe Discharge of Pressure Wave, Flames and Gases Elongated Vessels (Silos) Limits of Applicability Explosion Suppression Preliminary Remarks Description of Method

8 Contents IX Selection of the Sensor System Description of the Extinguishing Systems Selection of the Best Extinguishing Medium Limits of Applicability Extinguishing Agent Requirement Special Application Problems The Influence ofinitial Pressure Suppression of Explosions of Organic Peroxides Conclusions Safety Measures Against the Effects of Explosions in Pipelines Flame Barriers Preliminary Remarks Mechanical Flame Barriers Preliminary Remarks Explosion Barriers Long Time Flame Barriers Detonation Barriers Automatic Extinguishing Barrier Explosion Relief Venting Preliminary Remarks Relief Venting Device for the End of a Pipeline Bursting Discs, Activated Discs Explosion Doors Spring Loaded Valves Rapid Action Valves " Conclusions Summary References Part III Practical Applications of Protective Measures on Technical Equipment Preliminary Remarks Protective Measures for Equipment Grinders., Preliminary Remarks Parameters Influencing the Pressure vs. Time Course of Explosions Conclusions

9 x Contents 2.2 Bag Slitting Machines Preliminary Remarks The Application of Combined Protective Measures Fluid Bed Driers and Granulators Preliminary Remarks The Application of Secondary Protective Measures Basic Requirements of the Apparatus Square Shape Round Shape Conclusions Explosion Relief Venting Relief on Product Side of Filter Relief on Clean Side of Filter Explosion Suppression Additional Requirements Dust Separation Filters Preliminary Remarks Pocket Filters Application of Explosion Relief Venting Conclusions Hose Filters Application of Explosion Relief Venting The Location of the Ignition Source Within the Filter Housing Explosion Propagation from a Pipeline Application of Explosion Suppression Conclusions Safeguards on Combined Equipment Preliminary Remarks Grinding Installations Protection by Inerting Protection by Relief Venting Protection by Explosion SuppreSSion Spray Drying Installations Protection by Inerting Protection by Explosion Relief Venting Protection by Explosion Suppression Conclusions Closing Remarks References Subject Index