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Proceedings of the Symposium on the Handling of Solids
Book Reviews observers who make daily determinations of smoke in the atmosphere by the smoke filter method receive no help either with the shortcomings of the apparatus or with the more subtle difliculties of expressing and interpreting the results. The equally numerous users of the daily hydrogen peroxide method for sulphur dioxide receive little better treatment. On the descriptive side, the inadequacy of the twenty pages on the effects of air pollution on materials (and very inadequate pages they are) may be compared with the decision to give fifteen pages to such a marginal aspect of air pollution as ‘Air Ions’. The chapter on liquid scrubbing is interesting in that after sections on Classification, Principles, and Equipment, the Snal section on ‘An Example of the Use of Scrubbers* is given over to a process--the F&am-Simon Carves Ammonia Process-that has never been operated on anything more than a large pilot-plant scale, and the failure to mention this raises a doubt as to how much more of the information in the book may be misleading. The only process of flue-gas washing to remove sulphur dioxide that is operated on a full scale anywhere in the world-the process used at Battersea and Bankside Power Stations in London gets two paragraphs in a separate chapter headed ‘Water Pollution Potemial of Air Pollution Control Devices’. And. as a final examule, the ‘Selected List of Major Air Pollution Surveys’ contains the Leicester Survey, made in 1937-9 by DSIR with a man and a boy, but makes no mention of the DSIR co-operative survey of Gt. Britain, now the National Survey, conducted with the help of 569 local authorities and others making observations at some 2240 sites throughout the country. Looking back again at the contents of each chapter the only principle to emerge-and it is overwhelmingly apparent in every chapter-is the selection of American and the omission of European material. The publishers are not entirely to be blamed for this as their American market may prefer it this way, and it would still be possible to write a balanced account of air pollution within such a restrictive framework. But this book is far from being such an account. S. R. CRAXFORD.
argon, oxygen-free argon/nitrogen mixtures and very dry air. The puritlcation processes which the authors describe in detail include high-temperature “gettering” reactions of oxygen with reactive metals, reversible physical adsorption of water vapour and organic solvents and low temperature distillation of argon. They also outline the many potential applications of adsorption on molecular sieve type materials. The important design principles involved in the engineering of complete systems are mentioned. The book has been condensed from what wuld well have been a vast tome of detail into a useful introduction to a very new field of process engineering. Its main utility will be an indication of what can be achieved in the field of very pure atmospheres for a given wst and an introduction to some methods of tackling the problem. In an industry which until recently has not had to be cost-conscious by industrial standards it is noteworthy that the authors have paid close attention to actual costs, and they outline potential developments which could reduce these significantly. At first sight the costs of providing what would be only a service to some other industrial process seem quite enormous. To illustrate this, one could quote the authors’ figure of ElOO,OOOcapital- cost and an annual operating East of f10.000/1000 fts of workinn volume maintained at the highest ievel of argon purity.%n the other hand they state that by accepting slightly lower standards of gas purity these figures could be reduced to a tenth for the same working volume, and if normal industrial oxygen-free or dry atmospheres are used the costs would be very much lower. One would infer from this that unless the main process concerns a very expensive material such as plutonium or very small articles such as transistors, a most important decision will be that of selecting the gas purity really needed. Perhaps the only criticism of the book lies in the very brief discussion offered on methods of arriving at the latter. ’ The timely issue of this book will no doubt stimulate further application of the techniques described in other industries. It will be of particular value to engineers not familiar with the specialised field of atomic energy who are dealing with new processes requiring very high standards F. L. D. CLOETE of purity.
P. A. F. Wrurs and S. E. Sr+nru, Inert Atmospheres la the Chemical, Metalhugleal aad Atomic Energy Iadustrles. Butterworth, London, 1962. viii + 235 pp., 50s.
proeeedurgs
Tr-ns book is primarily concerned with the high purity inert atmosphere facilities developed in accordance with the special requirements of the atomic energy industry. The authors have dealt exclusively with recirculating gas purification systems where specific contaminants have been reduced to levels of a few parts per million. As they point out, it would be highly uneconomic to attempt to maintain these levels of purity by a simple oncethrough purge of nitrogen or argon, and they also show the necessity for the working volume to be enclosed in a glove-box constructed to very high standards of integrity. All aspects of the subject are mentioned from scientillc principles to costs and hints on operation. Most of the book consists of descriptions of experimental results and techniques selected from an extensive development programme carried out at Aldermaston, and it is fully illustrated with photographs and diagrams including useful details. The inert atmospheres discussed include high purity
Trns title may be misleading. Many readers will infer that the topic was the movement of materials by mechanical means. A better title might have been “The Behaviour of Systems of Particulate Solids in Bulk” but this would probably not have attracted so large an audience to the lecture hall at Olympia. This subject has not received great attention from r&&h workers, and designers have had to work mainly bv rule-of-thumb, or have introduced a fluid into the equipment to facilitate design and operation. Is this because solids systems are very difficult to detine completely, and therefore difficult to investigate in a systematic way? The texts of ten papers are reproduced in this book (87 pp.), together with thirteen pages of discussion. Three of the papers are by German authors (one of these is in the German text) and one by an American. Each deals with solid particulate systems, except for the last two in the book, which are on the design of weighing equipment.
559
.
of the symlMXJhlm 011 the HandBag of solids. (Inst. Chem. Eng., London 1962. 100 pp., 25s.)
Book Reviews The first two papers are concerned with forces acting between particles under compaction; the next with adhesion of starch, iron and iron oxide particles to substrates of similar composition, after the application of detaching forces up to 105g. A paper by Prof. A. W. JEMKE, of the University of Utah, on “Gravity Flow of Solids”, probably has the widest field of application. It summarizes 9 years’ work leading to the development of apparatus for measuring direct shear under controlled strain, in samples of bulk solids previously consolidated under controlled pressure and moisture content. The results may be applied to the design of storage hoppers in which a flow pattern may be predicted. For practical details, which the paper lacks: the-reader is referred to a University of Utah Enaineerina Exueriment Station Bulletin, which is now out of print, alihough copies are in the hands of several U.K. workers, and one was presented by Prof. JENIKBto the library of the Institution of Chemical Engineers. The next three papers deal with solids in motion in mixers and pipes, and the eighth with the concept of a breaking index for describing the extent of attrition of minerals during conveying. This is a mixed bag, and few answers to design problems are provided as ready-to-use empirical formulae, but these accounts of original work indicate how much is yet to be discovered about the behaviour of solids systems. P. L. BALDWIN
V. R. G~WAIUKERand F. H. GARNER, Analysis of Heat and Mass Transfer beIween Solid Wall and Fluid Streams at Both Low and High Reynolds Numbezs. AERE-R 4197 (1962) H.M. Stationery Office. 7s. THIS latest in a long line of “analogies” is based on the selection of an empirical equation to express the eddy viscosity as a function not only of the dimensionless distance from the wall (y+), but also of the Reynolds number. This approach is based on the observation that the u+ to y+ function has been shown experimentally to depend on Reynolds number. The assumed empirical equation for eddy viscosity is
employed to derive the relation between u+ and y+; the result is shown to compare well with experimental data at each of several Reynolds numbers. Assuming the equation for eddy viscosity to hold for eddy conductivity, the authors then proceed to calculate dimensionless temperature and concentration profiles for heat and mass transfer. Finally, the predicted relation between Stanton number and Prandtl (or Schmidt) number is compared with a considerable collection of experimental data on heat and mass transfer for rotating cylinders and flow in conduits. The agreement is impressive. Evidently the allowance for the trend with Reynolds number leads to a somewhat better correlation with the data then obtained by Deissler, though the improvement is not remarkable at Prandtl or Schmidt numbers from 1 to 1000 and Reynolds numbers from 10000 to 50000. T. K. SHERWOOD
D. H. HANSON, J. H. DIJFFIN and G. F. SOMERVILLE, Computation of Multistage Separation Processes. Reinhold, New York 1962. viii + 361 pp., 70s. Tms BOOK consists of four short chapters (36 pages in all) describing the fundamental mathematics of the calculation of multistage multicomponent separation processes, together with ten distinct computer programs adapted to various distillation and extraction problems. The introductory chapters include a good description of the specification problem, that is, discovering what variables are disposable by the calculator. The programs are written in a version of IBM FORTRAN and are souhisticated enough to reauire a large computer and to be of immediate value 70 the designer of petroleum separation plant. Each program has a short description of how it has been built up and how it works. This book will be of most value to the man whose problem is comprehended in one of the situations for which these programs are written. In this respect the book may be compared to a collection of standard methods of preparative Organic Chemistry, and should thus take its place in the reference library of any organisation concerned with computing for chemical engineers. H. P. HUTCHISON.
560
argon, oxygen-free argon/nitrogen mixtures and very dry air. The puritlcation processes which the authors describe in detail include high-temperature “gettering” reactions of oxygen with reactive metals, reversible physical adsorption of water vapour and organic solvents and low temperature distillation of argon. They also outline the many potential applications of adsorption on molecular sieve type materials. The important design principles involved in the engineering of complete systems are mentioned. The book has been condensed from what wuld well have been a vast tome of detail into a useful introduction to a very new field of process engineering. Its main utility will be an indication of what can be achieved in the field of very pure atmospheres for a given wst and an introduction to some methods of tackling the problem. In an industry which until recently has not had to be cost-conscious by industrial standards it is noteworthy that the authors have paid close attention to actual costs, and they outline potential developments which could reduce these significantly. At first sight the costs of providing what would be only a service to some other industrial process seem quite enormous. To illustrate this, one could quote the authors’ figure of ElOO,OOOcapital- cost and an annual operating East of f10.000/1000 fts of workinn volume maintained at the highest ievel of argon purity.%n the other hand they state that by accepting slightly lower standards of gas purity these figures could be reduced to a tenth for the same working volume, and if normal industrial oxygen-free or dry atmospheres are used the costs would be very much lower. One would infer from this that unless the main process concerns a very expensive material such as plutonium or very small articles such as transistors, a most important decision will be that of selecting the gas purity really needed. Perhaps the only criticism of the book lies in the very brief discussion offered on methods of arriving at the latter. ’ The timely issue of this book will no doubt stimulate further application of the techniques described in other industries. It will be of particular value to engineers not familiar with the specialised field of atomic energy who are dealing with new processes requiring very high standards F. L. D. CLOETE of purity.
P. A. F. Wrurs and S. E. Sr+nru, Inert Atmospheres la the Chemical, Metalhugleal aad Atomic Energy Iadustrles. Butterworth, London, 1962. viii + 235 pp., 50s.
proeeedurgs
Tr-ns book is primarily concerned with the high purity inert atmosphere facilities developed in accordance with the special requirements of the atomic energy industry. The authors have dealt exclusively with recirculating gas purification systems where specific contaminants have been reduced to levels of a few parts per million. As they point out, it would be highly uneconomic to attempt to maintain these levels of purity by a simple oncethrough purge of nitrogen or argon, and they also show the necessity for the working volume to be enclosed in a glove-box constructed to very high standards of integrity. All aspects of the subject are mentioned from scientillc principles to costs and hints on operation. Most of the book consists of descriptions of experimental results and techniques selected from an extensive development programme carried out at Aldermaston, and it is fully illustrated with photographs and diagrams including useful details. The inert atmospheres discussed include high purity
Trns title may be misleading. Many readers will infer that the topic was the movement of materials by mechanical means. A better title might have been “The Behaviour of Systems of Particulate Solids in Bulk” but this would probably not have attracted so large an audience to the lecture hall at Olympia. This subject has not received great attention from r&&h workers, and designers have had to work mainly bv rule-of-thumb, or have introduced a fluid into the equipment to facilitate design and operation. Is this because solids systems are very difficult to detine completely, and therefore difficult to investigate in a systematic way? The texts of ten papers are reproduced in this book (87 pp.), together with thirteen pages of discussion. Three of the papers are by German authors (one of these is in the German text) and one by an American. Each deals with solid particulate systems, except for the last two in the book, which are on the design of weighing equipment.
559
.
of the symlMXJhlm 011 the HandBag of solids. (Inst. Chem. Eng., London 1962. 100 pp., 25s.)
Book Reviews The first two papers are concerned with forces acting between particles under compaction; the next with adhesion of starch, iron and iron oxide particles to substrates of similar composition, after the application of detaching forces up to 105g. A paper by Prof. A. W. JEMKE, of the University of Utah, on “Gravity Flow of Solids”, probably has the widest field of application. It summarizes 9 years’ work leading to the development of apparatus for measuring direct shear under controlled strain, in samples of bulk solids previously consolidated under controlled pressure and moisture content. The results may be applied to the design of storage hoppers in which a flow pattern may be predicted. For practical details, which the paper lacks: the-reader is referred to a University of Utah Enaineerina Exueriment Station Bulletin, which is now out of print, alihough copies are in the hands of several U.K. workers, and one was presented by Prof. JENIKBto the library of the Institution of Chemical Engineers. The next three papers deal with solids in motion in mixers and pipes, and the eighth with the concept of a breaking index for describing the extent of attrition of minerals during conveying. This is a mixed bag, and few answers to design problems are provided as ready-to-use empirical formulae, but these accounts of original work indicate how much is yet to be discovered about the behaviour of solids systems. P. L. BALDWIN
V. R. G~WAIUKERand F. H. GARNER, Analysis of Heat and Mass Transfer beIween Solid Wall and Fluid Streams at Both Low and High Reynolds Numbezs. AERE-R 4197 (1962) H.M. Stationery Office. 7s. THIS latest in a long line of “analogies” is based on the selection of an empirical equation to express the eddy viscosity as a function not only of the dimensionless distance from the wall (y+), but also of the Reynolds number. This approach is based on the observation that the u+ to y+ function has been shown experimentally to depend on Reynolds number. The assumed empirical equation for eddy viscosity is
employed to derive the relation between u+ and y+; the result is shown to compare well with experimental data at each of several Reynolds numbers. Assuming the equation for eddy viscosity to hold for eddy conductivity, the authors then proceed to calculate dimensionless temperature and concentration profiles for heat and mass transfer. Finally, the predicted relation between Stanton number and Prandtl (or Schmidt) number is compared with a considerable collection of experimental data on heat and mass transfer for rotating cylinders and flow in conduits. The agreement is impressive. Evidently the allowance for the trend with Reynolds number leads to a somewhat better correlation with the data then obtained by Deissler, though the improvement is not remarkable at Prandtl or Schmidt numbers from 1 to 1000 and Reynolds numbers from 10000 to 50000. T. K. SHERWOOD
D. H. HANSON, J. H. DIJFFIN and G. F. SOMERVILLE, Computation of Multistage Separation Processes. Reinhold, New York 1962. viii + 361 pp., 70s. Tms BOOK consists of four short chapters (36 pages in all) describing the fundamental mathematics of the calculation of multistage multicomponent separation processes, together with ten distinct computer programs adapted to various distillation and extraction problems. The introductory chapters include a good description of the specification problem, that is, discovering what variables are disposable by the calculator. The programs are written in a version of IBM FORTRAN and are souhisticated enough to reauire a large computer and to be of immediate value 70 the designer of petroleum separation plant. Each program has a short description of how it has been built up and how it works. This book will be of most value to the man whose problem is comprehended in one of the situations for which these programs are written. In this respect the book may be compared to a collection of standard methods of preparative Organic Chemistry, and should thus take its place in the reference library of any organisation concerned with computing for chemical engineers. H. P. HUTCHISON.
560