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Pneumatic Conveying Design Guide

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Pneumatic Conveying Design GuideThis page intentionally left blank Pneumatic Conveying Design GuideSecond EditionDavid MillsAMSTERDAM BOSTON HEIDELBERG LONDON NEW YORK OXFORD PARISSAN DIEGO SAN FRANCISCO SINGAPORE SYDNEY TOKYOElsevier Butterworth-HeinemannLinacre House, Jordan Hill, Oxford OX2 8DP200 Wheeler Road, Burlington, MA 01803First published 1990Second edition 2004 David Mills 2004This publication contains material from PneumaticConveying Design Guide 1990 which was written by Dr David Mills under contract with the Department ofTrade and Industry. Crown copyright 1990. Reproducedwith the permission of the Controller of Her MajestysStationery OfcePermissions may be sought directly from ElseviersScience and Technology Rights Department in Oxford,UK: phone: 44-0-1865-843830; fax: 44-0-1865-853333; e-mail: [email protected] You may alsocomplete your request on-line via the Elsevier homepage(http://www.elsevier.com), by selecting CustomerSupport and then Obtaining PermissionsAll rights reserved. No part of this publication may bereproduced in any material form (including photocopyingor storing in any medium by electronic means and whetheror not transiently or incidentally to some other use of thispublication) without the written permission of the copyright holder except in accordance with the provisionsof the Copyright, Designs and Patents Act 1988 or underthe terms of a licence issued by the Copyright LicensingAgency Ltd, 90 Tottenham Court Road, London, EnglandW1T 4LP. Applications for the copyright holders writtenpermission to reproduce any part of this publication shouldbe addressed to the publisherBritish Library Cataloguing in Publication DataA catalogue record for this book is available from theBritish LibraryLibrary of Congress Cataloging in Publication DataA catalog record for this book is available from the Libraryof CongressISBN 0 7506 5471 6Typeset by Charon Tec Pvt Ltd, Chennai, IndiaPrinted and bound in Great Britain For information on all Butterworth-Heinemann publications visit our website at www.bh.comContentsPreface xiPart A: Systems and Components1. Introduction to pneumatic conveying and the guide 031.1 Introduction 031.2 Pneumatic conveying 031.3 Information provided 131.4 Review of chapters 141.5 Denitions 201.6 Nomenclature 25References 282. Review of pneumatic conveying systems 292.1 Introduction 292.2 System types 292.3 System requirements 482.4 Material property inuences 50References 533. Pipeline feeding devices Part I: Low pressure and vacuum 543.1 Introduction 543.2 Rotary valves 583.3 Screw feeders 683.4 Venturi feeders 693.5 Gate lock valves 713.6 Suction nozzles 733.7 Trickle valves 763.8 Blow tanks 77References 794. Pipeline feeding devices Part II: High pressure 804.1 Introduction 804.2 Screw feeders 814.3 Rotary valves 824.4 Blow tanks 824.5 Lock hoppers 101References 1035. Pipelines and valves 1045.1 Introduction 1045.2 Pipelines 1045.3 Valves 1105.4 Rubber hose 114References 1166. Air movers 1176.1 Introduction 1176.2 Types of air mover 1176.3 Air compression effects 1306.4 Pre-cooling systems 1376.5 Nomenclature 137References 1387. Gassolid separation devices 1397.1 Introduction 1397.2 Dust control 1407.3 Separation devices 1417.4 System considerations 150References 1518. System selection considerations 1528.1 Introduction 1528.2 Variables involved 1538.3 Variables investigated 1558.4 Material compatibility 1648.5 Design curves 1648.6 Power requirements 1728.7 System selection considerations 177Part B: System Design9. Air ow rate evaluation 1839.1 Introduction 1839.2 Volumetric ow rate 1869.3 The inuence of pressure 1909.4 Stepped pipeline systems 1969.5 Pipeline purging 2029.6 The inuence of temperature 2039.7 The inuence of altitude 2089.8 The use of air mass ow rate 2099.9 Nomenclature 21010. Air only relationships 21110.1 Introduction 21110.2 Pipeline pressure drop 21110.3 Venturi analysis 224vi CONTENTS10.4 Air ow rate control 22710.5 Stepped pipelines 23210.6 Nomenclature 234References 23511. Conveying characteristics 23611.1 Introduction 23611.2 Single phase ow 23711.3 Gassolid ows 23911.4 The determination of conveying characteristics 24311.5 Energy considerations 24711.6 Component pressure drop relationships 25211.7 Nomenclature 257References 25712. Conveying capability 25812.1 Introduction 25812.2 The inuence of materials 25812.3 System capability 283References 28613. Material property inuences 28713.1 Introduction 28713.2 Conveying modes 28713.3 Conveying capability correlations 29413.4 Material grade inuences 30513.5 Material degradation effects 311References 31814. Pipeline scaling parameters 31914.1 Introduction 31914.2 Scaling requirements 31914.3 Conveying distance 32014.4 Pipeline bore 32714.5 Pipeline bends 33314.6 Vertical pipelines 34214.7 Pipeline material 34614.8 Stepped pipelines 349References 35315. Design procedures 35515.1 Introduction 35515.2 The use of equations in system design 35515.3 The use of test data in system design 36715.4 Typical pipeline and material inuences 37216. Case studies Part I: Fine material 38416.1 Introduction 38416.2 Conveying data 38516.3 Procedure 38817. Case studies Part II: Coarse material 39517.1 Introduction 39517.2 Conveying data 39517.3 Procedure 39818. First approximation design methods 40418.1 Introduction 40418.2 Air only pressure drop method 40518.3 Universal conveying characteristics method 41319. Multiple use systems 42319.1 Introduction 42319.2 Multiple material handling 42419.3 Multiple delivery points 42619.4 The use of stepped pipelines 428References 435Part C: System Operation20. Troubleshooting and material ow problems 43920.1 Introduction 43920.2 Pipeline blockage 43921. Optimizing and up-rating of existing systems 46121.1 Introduction 46121.2 System not capable of duty 46321.3 Optimizing existing systems 46421.4 Case study 46721.5 Alternative methods of up-rating 47422. Operating problems 47822.1 Introduction 47822.2 Types of system 47922.3 System components 48222.4 System related 49122.5 Material related 494References 49723. Erosive wear 49823.1 Introduction 49823.2 Inuence of variables 49923.3 Industrial solutions and practical issues 512References 524viii CONTENTS24. Particle degradation 52624.1 Introduction 52624.2 Inuence of variables 53024.3 Recommendations and practical issues 53824.4 Pneumatic conveying data 54024.5 Particle melting 544References 54625. Moisture and condensation 54725.1 Introduction 54725.2 Humidity 54725.3 Air processes 55425.4 Energy considerations 56425.5 Nomenclature 56926. Health and safety 57026.1 Introduction 57026.2 Dust risks 57126.3 Conveying systems 57826.4 System components 58026.5 Conveying operations 58326.6 Explosion protection 587References 594Appendix 1: Determination of relevant material properties 595A1.1 Introduction 595A1.2 Particle size and shape 596A1.3 Particle and bulk density 602A1.4 Flow properties 605A1.5 Aeration properties 608References 616Appendix 2: Additional conveying data 617A2.1 Introduction 617A2.2 Materials and pipelines listings 617A2.3 Material properties listings 620A2.4 Additional conveying data 622Index 629CONTENTS ixThis page intentionally left blank PrefaceFor this second edition of the Pneumatic Conveying Design Guide I have followed asimilar format to the rst edition, in that it is in three parts plus appendices. There thesimilarity ends, however, for the material within these parts has been completely updated,substantially extended and re-developed to make it more accessible. The gures andillustrations are incorporated into the text for easy reference and the work is presentedin a single volume.The rst part of the Design Guide is devoted to Systems and Components and generalinformation on pneumatic conveying. This provides an understanding of dilute and densephase conveying modes, solids loading ratio and the inuence of pressure and convey-ing distance, and hence pressure gradient, on ow mechanisms and capabilities. It alsoprovides a review of major system types, feeding devices, air movers and ltrationdevices. A multitude of decisions have to be made with regard to the selection of aconveying system for a given duty and these chapters will be invaluable in this process.The new book brings all this information right up to date. Feeding devices are coveredin two chapters and are divided between high and low pressure (including vacuum)systems, following developments in this area with regard to blow tanks, rotary valvesand the application of lock hoppers. A completely new chapter has been included onpipelines and valves, which is probably unique, and reinforces the very practicalapproach of the book.The second part of the Design Guide is devoted entirely to System Design and is anentirely new and updated presentation. In this second edition I have incorporated the mainfeatures of the Abbreviated Design Guide in two case studies. These help to reinforcethe application of the scaling parameters and design procedures that are presented.Particular emphasis is placed on material types and conveying capability, since this is where there have been major advancements in the understanding of the technology.Different grades of exactly the same material can give totally different conveying resultsand so this aspect of conveying performance is highlighted. Entire chapters are devotedto topics such as First Approximation Design Methods and Multiple Use Systems. Forfeasibility studies, a quick solution is often required so that system economics can beassessed and particularly operating costs. There is often a need for a single system toconvey a number of different materials, and possibly to a number of different loca-tions, and these design issues are addressed.The third part of the Design Guide is devoted to System Operation and covers amultitude of very practical operational issues, such as damage to the plant when con-veying abrasive materials, and