Anatoly

The best book that I know of is : PNEUMATIC CONVEYING OF SOLIDS, A THEORETICAL AND PRACTICAL APPROACH, by GE Klinzing, RD Marcus, F Rizk and LS Leung. It is published by Chapman and Hall. Its ISBN is 0-412-72440-5.

David Mills has also written a good book on the subject but I do not have its details.

Regards

Mark Kilfoil ■

The book by Dr. Mills and Dr. Agarwal was published by

Trans Tech Publicatins Germany and has the following

bibliographic data (you will find contents pages etc.,

and also other interesting books on Pneumatic Conveying

in the Bookshop on this website.

(https://www.bulk-online.com)

Pneumatic Conveying Systems

Design, Selection, Operation and Troubleshooting With Particular Reference to Pulverised Fuel Ash

D. Mills and V.K. Agarwal

Pages: 350

Year: 2001

ISBN: 878491260

99.00 Euro / US$

From the Foreword

Fly ash conveying tends to be a rather neglected subject area, particularly with regard to books. Such neglect is probably due, in part, to the near zero value of the commodity. Having worked in this particular area for many years, however, the authors have recognized a definite need for such a book. System design is not straightforward and errors in component specification tend to be made on a regular basis. A particular problem with fly ash is that the material is automatically graded in the collection hoppers in boiler plant, and different grades of fly ash can have very different conveying characteristics.

The efficient handling of fly ash, however, is essential for the smooth running of the associated power plant. If ash accumulations in boiler hoppers are not cleared, for any reason, the boiler plant will generally have to be shut down and the financial consequences can be quite considerable. Fly ash handling almost represents an industry on its own, with a multitude of companies involved in the design, installation and operation of conveying equipment. In India alone fly ash generation is rapidly approaching 100,000,000 tonne/yr and is set to continue rising at a high rate into the forseeable future.

Much confusion exists around the definition of dilute and dense phase conveying and so this is an issue that is addressed in detail. In general, in a conventional positive or negative pneumatic conveying system, coarse grades of ash can only be conveyed in dilute phase, and so high values of conveying air velocity must be employed, with the ash conveyed in suspension in the air. Fine ash, however, can usually be conveyed in dense phase, non suspension flow, and with very much lower conveying air velocities but this capability is dictated very much by the concentration of the ash in the air, the pressure drop available and the conveying distance.

The critical design parameter in any pneumatic conveying system is the conveying line inlet air velocity. With different grades of the same material requiring different values of this velocity, considerable care must be exercised in the design and specification of the plant and components if different grades are to be conveyed in a common system. An added problem is that the different grades of fly ash are generally at different temperatures and this adds to the complexity of specifying air requirements and calculating air velocity values. Yet another problem is the fact that fly ash is generally a very abrasive material and so component specification must take this into account also.

In systems where fly ash is drawn from ash hoppers to intermediate silos by vacuum conveying, and is then conveyed onward by positive pressure to bunkers for disposal, further problems can result in this onward conveying if a mix of both fine and coarse ash has to be handled. Emphasis is given to both system design and system operation in the book, and so problems of this nature are considered in two ways. For a new system the conveying variables are highlighted so that they should be taken into account in the system analysis and design procedures. For existing systems two chapters are devoted specifically to troubleshooting and numerous equations are presented throughout the book that can be used to check operating parameters. Stepped pipeline systems are a design feature that is given prominence, and this applies to both positive pressure and vacuum conveying systems. Several case studies are included to illustrate the design procedures for both fine and coarse ash, and these are used further to illustrate the basic fact that there is no one fixed set of design and conveying parameters for a given conveying system. An infinite combination of air supply pressures and pipeline bores is generally capable of meeting any conveying duty, limited only by the availability of standard pipeline bores and the problem of accommodating very high air supply pressures. It is to be recommended that alternative designs should be considered for any system and that these should be evaluated in terms of both capital costs and running costs. By this means a true economic cost comparison can be made, in which it should also be possible to include maintenance costs.

Much of the conveying data presented in the book was obtained by students running pneumatic conveying test facilities. This is why such high values of solids loading ratio and low values of conveying air velocity have been achieved in much of the work presented. The authors often state in short courses that anyone can convey fine fly ash and cite the case of our many students and their results in order to encourage delegates attending. From our experience with coarse ash, and visiting innumerable power plants where the ash is also at a high temperature, however, we do recognize the many problems and we hope that this book will help in gaining a clearer understanding of the issues, the design process and the operating problems.

Dr. David Mills

Dr. V.K. Agarwal ■

Dear Sir,

Thank you for your interest in our pneumatic conveying systems. We

manufacture a wide range of pneumatic conveying systems from rock and sand conveyors, seed conveyors for marmers, grain conveyors for grain terminals and ship unloaders for ports. Your "table" of component requirements was not attached. Please advise us of your requirement.

Best regards,

Frank Christianson

Christianson Systems, Inc

Blomkest, MN USA

Tel: 320-995-6141 ext 364

e-mail: fchristianson@christianson.com ■