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Solid-Gas Separation
150
Book reviews
Solid-Gas Separation. By L SVAROVSKY. pp. x i + 123, limp cover, $40.50 IDfl. 95L Elsevier. Amsterdam, 1981. This third volume of the Handbook of Powder Technology deals, in fact, with coarse aerosols and their removal from flowing gas by settling, impaction, scrubbing, electrostatics and filtration. A distinct coyness about particle size is evident, dirty words to engineers, and those prurient minds which probe into this will be surprised to find a diagram on p. I l 1 which presents the cut size of a high efficiency cyclone as 3/~m and that of a high efficiency venturi scrubber as 0.04/~m. There is a considerable number of formulae, 97 references and 3 pages of introduction to the mechanics of particle motion, from which the basic physics is lacking. The second chapter, of 18 pages, is about the efficiency of separation of solid or liquid particles from gas and is dealt with on a mass basis, total and grade efficiencies being explained and three methods of finding the 50 ~0 penetration on cut size are given which do not require knowledge of the full grade efficiency curve. The theory of separators in series is given. The next 27 pages deal with settling chambers, cyclones and other centrifugal devices with guidance on m a x i m u m dust concentration, pressure drop and cut size. Fifteen pages on wet separation, or scrubbers, follow with acknowledgement to the "'Scrubber H a n d b o o k " (v. J. Aerosol Sci. 4, 340, 1973). The next chapter, on electrostatic precipitation, has 15 pages and reviews the systems in use in a general way. High resistance of the collected dust is identified as a cause of inefficiency but there is no discussion of recent Japanese work on the suppresion of backdischarge. Chapter 6 on filters has 20 pages, half of which are devoted to the physical ideas behind mechanical filtration, but the author has not appreciated the single fibre concept which in conjunction with the fan model has led to the most accurate theoretical representation of high efficiency filters operating at low face velocities. The rest of the chapter describes briefly industrial bag filters, air conditioning filters, high efficiency filters and sand bed filters with a few notes on filter testing. The final chapter of this book deals with the economics of gas cleaning and the selection of equipment. C. N+ DAVIES
Book reviews
Solid-Gas Separation. By L SVAROVSKY. pp. x i + 123, limp cover, $40.50 IDfl. 95L Elsevier. Amsterdam, 1981. This third volume of the Handbook of Powder Technology deals, in fact, with coarse aerosols and their removal from flowing gas by settling, impaction, scrubbing, electrostatics and filtration. A distinct coyness about particle size is evident, dirty words to engineers, and those prurient minds which probe into this will be surprised to find a diagram on p. I l 1 which presents the cut size of a high efficiency cyclone as 3/~m and that of a high efficiency venturi scrubber as 0.04/~m. There is a considerable number of formulae, 97 references and 3 pages of introduction to the mechanics of particle motion, from which the basic physics is lacking. The second chapter, of 18 pages, is about the efficiency of separation of solid or liquid particles from gas and is dealt with on a mass basis, total and grade efficiencies being explained and three methods of finding the 50 ~0 penetration on cut size are given which do not require knowledge of the full grade efficiency curve. The theory of separators in series is given. The next 27 pages deal with settling chambers, cyclones and other centrifugal devices with guidance on m a x i m u m dust concentration, pressure drop and cut size. Fifteen pages on wet separation, or scrubbers, follow with acknowledgement to the "'Scrubber H a n d b o o k " (v. J. Aerosol Sci. 4, 340, 1973). The next chapter, on electrostatic precipitation, has 15 pages and reviews the systems in use in a general way. High resistance of the collected dust is identified as a cause of inefficiency but there is no discussion of recent Japanese work on the suppresion of backdischarge. Chapter 6 on filters has 20 pages, half of which are devoted to the physical ideas behind mechanical filtration, but the author has not appreciated the single fibre concept which in conjunction with the fan model has led to the most accurate theoretical representation of high efficiency filters operating at low face velocities. The rest of the chapter describes briefly industrial bag filters, air conditioning filters, high efficiency filters and sand bed filters with a few notes on filter testing. The final chapter of this book deals with the economics of gas cleaning and the selection of equipment. C. N+ DAVIES