i
I
CHEMICAL ENGINEERING REVIEWS
I I
UNIT
I
I
A u m M A m x has come to filtering operations. I n a sense, of course, \ye have had automatic filters for 50 yearsever since the first continuous vacuum filter arrived on the scene-and the semiautomatic cycling of batch centrifugal filters is old hat. Mechanical or electronic monitors of the quality of a product stream-for example, of its turbidity-also are not new. Until recently, however, the complete automation of high-pressure or low-rate filtrations was not known. I n 1956 the picture changed, and automatic operation of the most versatile of all filters, the batch pressure filter, became a commercial reality. While there is still a way to go, automatic control, with its usual economy of time, labor, and irregularity, is now available for pressure leaf filters and for one type of filter press, the Burwell. The trend in filtration equipment, in fact, is toward the improved rather than the new. The past year brought forth no equipment brand new in either principle or form, but there were a number of improvements in design, such as clean-up leaves for the heel in batch pressure filters, better backwashing or cake flushing arrangements, and higher filtrate delivery capacity in continuous rotary vacuum filters, continuous precoat filters, and ultrafilters. With filter media, too, it is improvement rather than novelty. The emphasis has been on the enhancement both chemically and physically of the fibers and fabrications that are now available as filter media: Superfine polymer fibers join their glass counterparts; cotton treated with rare earth
486
compounds is dn inexpensive alkali resistor; glass fibers that are acid-etched during their formation result in improved flex and abrasion resistance; woven textile is formed from polyethylene, and paper from glass and from nylon. Some of these items are still experimental, but all are successful. O n the research and development side there has been gratifying activity. I n addition to a half-day symposium devoted by the American Institute of Chemical Engineers to filtration (and another being planned, possibly for 1957), no less than a dozen serious research reports on the mechanism or application of filtration appeared in the past year, many of these with immediate practical implications. The greatest portion of these originated with the manufacturers of filters and their accessories-a heartening change from the situation of 10 years ago. Several came from univrrsities. The most significant of them all, Grace's two papers on the
INDUSTRIAL AND ENGINEERING CHEMISTRY
struciure and perlorniance of filter media, came from a user of filters, membrr of the process industries. Less is kno\vn today about filter media and that type of clarification called filter-medium or depth filtration than any other portion of the field. Grace's contributions do not remedy this ignorance, but they point a clearer way to its remedy than has heretofore existed. Many more data must be collected before we can realize any firm relation between the observable (and contrivable) physical structure of filter media and the way the media perform, and under the stimulus of Grace's work we can expect them to be forthcoming. hlean\vhile the users of filter media will find Grace's methods and results valuable. Furthermore, some of the confusion residing in clarification, notably in viscose filtration, will be dispelled b y Gracr's approach to the filter-medium filtration la\vs. As for the status ol filtration theory
SHELBY A. MILLER received his B.S. (1935) from the University of Louisville and Ph.D. (1944) from the University of Minnesota. Miller, who taught a t Kansas University until September 1955, is now professor and chairman of the department of chemical engineering at the University of Rochester. He i s a licensed professional engineer and belongs to ACS, AIChE, the SCI, and the National Society of Professional Engineers.
and its value to the designers and operators of filters, there has been little change during the year. The validity of the porosity-surface-resistance relationship as correlated by the Kozeny-Carman law is well established, a t least within the limits of engineering accuracy. Work done during the past year has further confirmed this validity, while confirming a t the same time the sensitivity of the filtration resistance to small changes in porosity and surface. This in turn focuses attention on the aggregation process whereby filter cakes are formed and on those process conditions that influence the character of the aggregate. Herein lies a fertile field for future research, upon which further major advances in our ability to design and specify filters must wait. That the concepts of specific cake resistance and compressibility are of practical value in predesign and poststartup investigations is indicated by the number of papers that report careful studies based upon them. From heavy chemicals to foods to sewage sludge, careful explorations are the more significant because the campaigns were planned and the data interpreted in light of these concepts. Freedom to use the concepts outside the restrictions of constant pressure or constant rate, the recent results of Tiller’s derivations, should make them even more generally valuable. The status of washing and dewatering operations is less happy. Some work is being done, however, and it is conceivable that related research efforts concerning fluid dynamics and mass transfer within porous media will eventually contribute fruitfully to filtration practice. At present, the empirical approach is the only one available. The users of filters have shown vitality and even fresh thinking about their filtration problems. Brown’s “cute” idea is an example. T o arrange a filter medium so that either surface can be used for cake collection and then periodically to reverse the direction of filtration so that the filtrate can backwash the medium during the first interval after reversal may have serious limitations. For many slurries and many media it would be an impracticable technique, but it will have its places of usefulness, and it represents open-mindedness. So also do Grace’s approach to his research and the development of filtration-extraction a t the Southern Regional Research Laboratory. Such an attitude, coupled with the sort of efforts now beginning to be made by filter suppliers and reasonable activity in university laboratories, is sure to produce steady and significant advancement. Even among the processors of water, where tradition and the squeeze of economics have combined to make
change extremely difficult, there are stirrings. Pressure filtration and the use of diatomite, becoming more and more important in the treatment of industrial water, are being approached by municipal plants. Filtration rates on sand filters, once untouchable, have been steadily and scientifically advanced. One purification plant superintendent has complained that water filters are much too costly for their function and that it is high time that equipment designed in a completely different economic and technical era be critically scrutinized. This is very encouraging. This review, which reports the items underlying the preceding comments, follows the pattern evolved in previous years. The approximately 200 references cited represent about half the number encountered. Those cited include the major theoretical and development work and a selection of the most interesting and pertinent of the other subjects. Accessibility to the reader has been considered; there is greater emphasis on English language publications than on others. No attempt was made to cover the patent literature exhaustively, and those patents mentioned were encountered incidentally. The defense for this is the shortage of time, the multitude of patent items, and the belief that the content of equipment patent specifications is of limited value to all except the equipment manufacturer. As in the past, the scope of the review is conventional filtration for the 18 months preceding December 1956. Occasional reference is made to gas clarification, but such reference is largely incidental. Exclusion of the subject is expedient rather than logical. Excluded also are centrifugal separation and sedimentation, because they are covered elsewhere, and adsorptive percolation and biofiltration, because they are not really cognate.
Reviews The year produced one review of high distinction, and that one, oddly enough, is intended for laboratory rather than industrial practitioners. A part of Weissberger’s second edition appeared, carrying a revised and enlarged chapter on filtration by Cummins and Hutto ( 3 4 . The emphasis of the chapter is properly on laboratory practice, but the comprehensive coverage given and the inclusion of sections on filtration theory and the conduct of small-scale tests directed toward large-scale realization not only give the research chemist a good idea of the importance that filtration may assume if his process reaches the plant but also present the general reader, whether chemist or engineer, with a n admirable introduction to the subjects of cake filtration and ultrafiltration.
The best general industrial summary of the field was included by Smith and McCabe (6A, 7A) in their new textbook on chemical engineering unit operations. After introducing the student to the concept of permeability and to the Kozeny-Carman equation in an earlier section on flow through porous resistances (64, they present him with filtration (74 in the proper context of a chapter on mechanical separations. The mathematical development of cake filtration is brief but satisfactory, but cake washing receives only a nod. Equipment and media are given standard textbook treatment. One wishes that an already large book might have been allowed to run to a few more pages, so that a section on clarifying or filtermedium filtration could have been included. Two general reviews appeared in British trade journals. Refson (7 7A734, in a seven-part paper introduced with a short, nonmathematical statement (7 7A) about filtration principles and the state of the “art,” devoted most of his attention to filter media (72A), which he classified as controlled weaves (textiles), random weaves (unwoven fibrous aggregates), sinters (rigid porous media), and miscellaneous. Filters (which he regards as containers for filter media) were the subject of his two concluding installments (73A), in which he permits an erroneous inference about the productivity of continuous vacuum filters. Pratt ( 7 0 4 emphasized the importance of slurry preconditioning but missed the chance to follow up with useful detail. His lead-off section on theory is perilously oversimplified. The more valuable part of his paper is the second, dealing with a classification of industrial equipment and its applications. Two additional reviewers concerned themselves ‘with the theoretical principles of filtration, Volckman (76A), chiefly, and Orlicek (U), entirely. The former concisely summarized both cake filtration and clarification but also wrote briefly about certain filters and about filter fabrics. Orlicek’s paper, which is available in French as well as German, dealt critically with cake filtration theory and the concept of variable specific resistance (discussed further in the next section of this review). I t concluded with a summary of the inferences that have been drawn recently from the cake filtration rate equations about optimum conditions for batch and continuous filters and optimum dilution of a viscous prefilt. Although they are incidental to the research papers that they introduce, the reviews of the structure and permeability of filter media (5E)and of the mathematical’status of filter-medium filtration (6E)prepared by Grace are excellent. They are thorough, quantitative, crit-
VOL. 49, NO. 3, PART II
0
MARCH 1957
487
Further major advances in ability to design and specify filters must wait on more research into the aggregation process.
Table I.
Pressure and Gravity Filters and Accessories
Item
Application
Jet-flush pressure leaf Hter Precoat back-flush leaf filter Precoat candle-element filter Horizontal plate clarifier Nonmetallic plate clarifier Filter press with hydraulic cake flusher Vibrating diaphragm to assist cake discharge Filter leaf with rim lock Gear-shaped a t e r element Recovery leaf 6 Multicell granular-bed filter Self-cleaning strainer Self-cleaning strainer Magnetic separator and filter Surface agitator Automatic-cycle filter press
Table It.
Cake removal Eliminates bolts, rivets, solder Element in thickener Filter heel in pressure leaf filter Pressure filter for water Strains water at pump intake Strainer with automatic solids discharge Coolant reconditioning Granular bed reconditioning Semicontinuous discharge of heavy concentrates
Vacuum Filters and Accessories
Item Rotary drum filter Top-feed drum filter (double or single drum) Rotobelt drum filter with cloth belt High-rate continuous precoat filter Traveling-pan filter Rotary drum with heated leaves Self-cleaning filter Rotating magnetic filter Batch suction leaf filter Portable vacuum leaf Portable vacuum leaf
-4pplication High-rate pulp filtration Heavy metallurgical concentrates Removable surface for high-rate, plug-free filtration Uranium processing Wet process, phosphoric acid Melt filtration Paper-belt coolant conditioner with vacuum assistance Combined magnetic drum and vacuum drum Water, waste streams, plating solutions Reconditioning cooking oil Water filtration
ical, and well documented-and they are also good writing. Chemical Engineering published another of its useful inventory issues (ZA), indexing, listing, and briefly describing among its entries many filters, media, aids, and accessories offered by U. S. vendors. More specific reviews of filtration equipment and procedures for vegetable oil and water processors were prepared by Singleton (74A) and by Symons (75A), respectively. A revision of Chapter 11, “Filtration,” of the American Water Works Association’s monograph, “Water Quality and Treat-
488
Reference
Wet-discharge solids Industrial water Chemical and metallurgical Liquid polishing Liquid polishing Beet- sugar cake
ment” (now in its second edition, dated 1950) was published by the association ( 7 4 . The chapter provides details of both equipment and procedure for water filtration and includes sections on pressure sand filters and diatomite filters. Because of their close relevance to the theory of filtration, two papers that are really outside the field should be mentioned. The fourth annual review of fluid dynamics ( 5 A ) appeared last year and contained sections on flow through porous media and two-phase flow. A superb paper describing in pre-
INDUSTRIAL AND ENGINEERING CHEMISTRY
cise detail the experiments and publications of Henry Darcy that produced Darcy’s la\v and elaborating critically upon the law in contemporary context was written by Hubbert (&I) as a contribution to the Darcy Centennial Hydrology Symposium. Anyone who has suffered the confusion generated by the multiple quotations and misquotations of Darcy’s law and who has attempted, perhaps in vain, to lay hands on Darcy’s own report will find Hubhert’s paper a valuahle and pleasurable experience. Theory, Experiment, and Design
Permeability a n d Cake Filtration. Information adding support to the relationship between porosity and filtration resistance was developed by \-alleroy (77B). He calculated the average specific resistance of a slightly compressible (0.36 2 E 2 0.39) aggregate pf Lucite spheres from compression-permeability, vacuum filtration, and centrifugal washing tests. \‘\‘hereas the values agreed within 16y0 on the basis of equal coinpressive stress, they agreed within 3r/o on the basis of equal porosity; there was a difference of 30y0,however, between the value computed from these tests and that computed from the Rozeny-Carman equation in which the specific surface was evaluated from microscopic observations and k was taken as 5.0. I’alleroy surmised that the failure of the Kozeny-Carman equation might have been identified with the wide range of sphere sizes (3.5 to 115 microns) or with surface effects produced by the use of Dreft to simplify initial wetting of the spheres. I n any event, Valleroy’s data pointed to the extreme sensitivity of resistance to changes in effective porosity. Such interaction is supported by the observed dependence of the permeability of a consolidated aggregate-e.g., an oilsand core-on the wettability of the aggregate (2%) and on the presence of a bound layer of an immiscible fluid ( 7 2 3 ) . It is further supported by the notable effects of electrolytes on permeability, which may result from a dimension change produced in certain particles by the electrolyte [as Kennedy and Pfile (5B) postulated occurred in a core] or from the compactiIig of an unconsolidated aggregate ( 3 B ) . It casts doubt on the generality of simplified empirical correlations, such as that of Broivnell
FILTRATION and coworkers (7B)which applies invariant corrections to friction factors and Reynolds numbers intended to describe the permeability of consolidated aggregates of widely varying porosity. In spite of its sensitivity, the permeability-compression relationship is now reasonably well established as a useful tool for the evaluation of filterability. Tiller (70B)objected to the use of a permeability-compression cell on the grounds of its elaborateness and expense and showed that the filterability of a material can be described generally by use of data obtained with any convenient pressure filter and a pump of known head-discharge characteristic. The way in which porosity varies through a filter cake, a question of some disagreement, was examined by Hutto (4B), who used the techniques of injecting systematically spaced “puffs” of colored solids into a slurry stream being filtered in a transparent cell. Hutto found porosity decreasing from cake surface to filter medium, more rapidly near the surface; he also demonstrated by striking motion pictures the elasticity of a cake of wood pulp. A different approach to filtration was taken by Scheidegger. In a paper (8B)presented at a recent meeting, he applied to the filtration phenomenon the statistical treatment of the filter cake as a disordered aggregate of channels that he proposed two years ago for the permeation phenomenon (9B). To those unversed in statistical mechanics there seems to be little to recommend an assumed random disorder of channels and the consequent Gaussian distribution instead of an assumed random aggregation of solids and the consequent mean value of the Kozeny coefficient. Application of the Cake Equations. The power of the filtration rate equations to guide in design data collection and to establish desirable operating conditions continues to be displayed. The equations will enable the construction of simple nomographs describing rotaryfilter capacity in sugar processing (72C) ; furthermore, they will permit the interpretation of such variables as prefilt aging, as Okamura and Shirato (7C) showed in the extension of their work on ceramic slurries. Their usefulness in the establishment of operating optima has been mentioned (SA). Along the latter line, Sjenitzer (77C) extended the work of Reeves and Mondria (see 1951 and 1953 reviews) by using the constant-pressure equations to establish the effects of slurry feed concentration, recirculation of filtrate during washing, and recirculation of cake. He allowed for the resistance of the filter medium, although not rigorously. His conclusions are deprived of maximum generality because of his assumptions.
These and other criticisms were detailed in a written discussion following his paper (SC, 8C). The use of the constant-pressure equations to describe the operation of a continuous pressure m e r (@) and to specify continuous vacuum filters for corn gluten (70CJandsewage sludge (9C)was elaborated in oral presentations reported in last year’s review. These papers have since been published. Coackley and Jones (IC,3C) justly criticized the conventional procedure of laboratory testing sewage sludge filterability by dewatering it in a Buchner funnel until the cake cracks. They recommended the adoption of the specific resistance as the criterion and showed that reproducible values of the specific resistance could be obtained from either pressure or vacuum tests. In their complaint that mechanical equilibrium was reached in a compression-permeability cell only after 24 hours, they raised an interesting point that will bear watching by future users of such equipment, with whatever cake. The extremely slow consolidation rate of the sludge apparently is reflected in Jones’s (3C)treatment of filter press and rotary vacuum performance, as predicted from laboratory tests; his equations do not agree with the established ones. The specific resistance of a fiber mass has been recommended by Marteny and as the comparative criterion Olson (4‘) of degree of fiberizing in coarse pulp. Cake Washing and Dewatering. The washing of filtrate from the cake formed on a continuous rotary vacuum filter was investigated with a test leaf by Choudhury and Dahlstrom (30). They found that the exponential relationship proposed by Rhodes 20 years ago best described the washing performance, and they recommended this basis for the design of plant equipment. Their observations do not agree with the data of von Rosenberg (5D)for thick beds, for which a displacement curve of the expected form was found. Choudhury and Dahlstrom explained the difference on the basis of their relatively thin cakes. More experimental work is needed. Equally unpredictable is the dewatering time and degree achieved by airblowing a filter cake, this notwithstanding the valuable researches of Brownell and his coworkers of the past several years. Bate1 applied his recent conabout the liquid retention clusions (70) capacity of granular aggregates to the air-blowing of filter cakes (20). His claim is that air pressure used must exceed the capillary rise in the aggregate, but the latter unfortunately is not precisely calculable and only qualitative conclusions can be drawn. A more frankly empirical approach to the cake
dewatering problem was reported by Henderson and his associates (40).By use of the “correlating factor” proposed in the past by Dahlstrom, they correlated the dewatering of taconite concentrates on disk filters. The correlation was rough but, according to the authors, useful. Filter Media and Filter-Medium Filtration. A reliable and sound method of evaluating filter media has long been an unfulfilled goal. Usually the only criteria have been experience, coupled with physical and optical examination and with permeability measurements, although the calculation of an average pore size by the Kozeny-Carman equation and the measurement of the maximum pore by bubble pressure have been used (6E). With the appearance of two excellent and enlightening research reports by Grace (6E, 7E),however, the way is paved for the solution to this problem. In the first paper (6E),Grace described the use of mercury intrusion, a standard technique for the examimtion of consolidated porous masses (7E),for the determination of pore size distribution of fabric, bulk fiber, and sintered filter media. The most interesting of his results showed the sharp distinction between the dimensions of interfiber (80 microns) pores in woven textiles, and indicated that 30 to 50% of the pore volume is contributed by the interfiber pores, even in the high-twist yarn fabrics recently developed. The value of the latter apparently lies in a reduction not of the volume but of the dimension of the interfiber pores. In the following paper (7E),Grace investigated the performance of media whose structure he had examined by the filtration of very dilute (23 p.p.m.) suspensions of 5-micron iron carbonyl. In general, he observed the following in the course of a filtration: some particles initially bleeding through; an initial filtration period indescribable by any existing theory; a period obeying the Hermans-Bredte standard law; and a period obeying the cake law, even when no visible cake was being formed. [How generally this behavior would apply to more concentrated slurries cannot be stated, but it may shed light on the mysterious next-to-medium layer and account for the existence of an optimum filtering pressure in cases where, although experimentally observable, such an optimum cannot be reconciled with the cake equation. Orlicek (9A) suggested that it might stem from the discontinuity between cake and medium.] Grace’s observation of the multiregime behavior of filter-medium filtration and of the dependence of these regimes on the structure of the filter
VOL. 49, NO. 3, CART II a MARCH 1957
489
UNIT OPERATIONS REVIEW To ble 111. Type of Filter or Treatment
Process Applications Application
Electro-osmotic beneficiation Addition of certain bivalent cations Oscillating filter Coalescing filter Passage through scrubber, coalescing filter, desiccant bed Dilution of petroleum solvent with water Disk filters Pressure filters and filter aid Full flow filters Wire-cloth pressure leaf Rotary vacuum drum Horizontal vacuum table Rotary vacuum drum Stainless steel pressure filters Various types of filters Various filters and filtration conditions Various filters and filtration conditions Sand
Increased filtration rate of chilled wax precipitate Dewatering taconite Cleaning wax melts or emulsions Diesel locomotives Filtration of foots from crude oil Filtration of corn gluten Extraction of oil from flaxseed Washing esparto pulp Processing borsch and gefilte fish Plating industry Viscose filtration
Diatomite
Industrial and municipal water
Vacuum dewatering
Domestic sewage sludge
Table IV. Type Poly(viny1idene chloride) fiber Polyethylene cloth Rare earth-treated cotton Superfine thermoplastics Electrically treated glass Resin-impregnated cellulose Ceramic fibers Fibrous glass cartridges Nylon paper Glass paper Cemented polymer granules Resin-impregnated wood flour and diatomite Small-pore sintered metal Giass-bead bed Crushed graphite Nerofil carbon filter aid Coconut meat filter aid Support arrangement for precoat Improved diatomite feeder
Table V. Type Laboratory-sized clarifiers Small filters and accessories Small filters Small continuous filter Ultrafilters, large capacity Ultrafilters and accessories Ultrafilters Modified ultrafilter Inrtrument control valve
490
Reference
Clay Improved filtration of calcium sulfate from superphosphate Separation of solid amalgams from excess mercury Separation of immiscible liquids Cleaning gasoline or light fuel oil
Sugar processing Water clarification
(1OG)
(40)
(7G, 18G) (17G) (SG)
UOC) (8G) (11G)
UJG)
(12G, 16K)
( S E , J E , 8 E , 16E, l G , 15G) ( f Z C ,BG, 6G, 16G, 190, 21 G ) (BH, 6 H , 10H, I I H , X H , 17m ( I H , S H . 4H,b H , 7H, lJH, l4H) ( I C , SC, 9C, 9H, 18H,B8J)
Filter Media and Filter Aids Application Chemically resistant filter cloth Chemical resistance Caustic-resistant cloth Fine-particle filtration Abrasion and flex resistance Hot oil Hot gases Emulsion coalescence and clarification
Reference (1J)
(25J)
Elevated temperature Oil and water resistance Cartridges and plates Removes 40-micron particles Water filtration Strong alkali Food processing Diatomite filtration
Equipment
Laboratory Equipment and Ultrafilters Application General purpose Determination of liquid-solid equilibrium at high temperature Automatic process analyzer-controller General purpose Examination and control of water and sewage Prevention of air contamination during filtration Vacuum breaker for ultrafilter
INDUSTRIAL AND ENGINEERING CHEMISTRY
medium (presumably, also, on slurry characteristics and other pertinent variables) does much to clear up the disagreement that has long existed among investigators of viscose filterability. Takizawa and coworkers (72E),for example, have reported that viscose follows the Hermans-Bredte intermediate law and have attempted to interpret the constant with the size and number of filtered particles. Other investigators (3E, 4E, (?E) have recently found that viscose filterability depends on type or, more specifically, porosity of filter medium, and Ellefsen (.3E) has devised a statistical method of correcting for porosity variation. As Grace suggested last year (8.4), the principles involved in gas filtration and liquid filtration (particularly of the clarification type) are closely similar and should be intercorrelated. Thus, as observed by Cranston and Beynon (LE), effective gas filters transmit some particles; and so do liquid filters as observed by Grace 17E) and by Oliver (8C). Perhaps, therefor?, Cranston’s “transmission factor” is a criterion considerable for liquid clarifiers in certain services. Novel models like that used by Gallily (5E)to study idealized aerosol filtration may be valuable in teaching investigators about liquid filtration; so indeed may straight phenornenological studies of the behavior of dust filter fabrics (9E). Perhaps even the theory of screening that has been under study statistically by Steenberg and his associates (71E) for the past several years [and that has most recently been brought by Kub6t (70E) to deal with the case o f particle interaction] may provide insight to the problem of filtration. Researchers of the present have many intriguing lines to draw together.
Reference (6K) (3K, 8 K , l 4 K , 19K) (ZK, BOK)
(4W ( i K , 7 K , IOK) (12K,16K) (SK, 9K,1 6 K ,
Table I lists pressure and gravity filters and their accessories of noiel interest that Mere described during the year. Table I1 does the same for vacuum filtration equipmmt. Two brief summaries (7F, 2 F ) of German filters were published. T h e most important development in the operation of equipment is the automation of batch pressure filters. Zievers (397) described the types of control systems that can be applied to pressure leaf filters, A single unit may be automated for less than $2000, and batteries of filters at much less per unit. A clarifier using filter aid can be monitored against turbidity so that additional aid will be supplied if clarity diminishes (36F). ,4n ingenious proposal by Brown (3F) involves a filter so devised as to permit reversible filtration-first one face of the medium collects the cake, and then
FILTRATION the other while the first is backwashed by the filtrate. Many slurries would not yield to such treatment, but for those that will, the idea seems good. Incidentally, the cycle should be automated easily. A 60-micron screen vibrated sonically (27F) abets gravity or buoyancy to repel solids and transmit liquid. O n the other hand a pulsatory technique (32F) permits ion exchange beds to adsorb solute from slurries without filtering the solids. Process Applications, Table I11 contains the past year’s developments in filtration of various types of materials, including water, sewage, and industrial effluents. A brief annual review of sludge disposal and utilization again appeared (SH). Hudson (72H)revised his earlier “floc strength index” into a more generally satisfactory if equally empirical index of sand filtration rate. Papers by Bell reported a full-scale setup of sand and diatomite filters side by side ( 4 H ) whereby a long-range comparison study was undertaken ( 3 H ) . Filter Media and Filter Aids. A listing of filter fibers, cloths,. paper, and filter aids of recent interest is contained in Table IV. Methods of improving natural ( 2 7 5 ) and protein fibers ( 3 2 5 ) . have been reviewed, and other reviews cavered filter papers (76.7, 17.7) and inorganic papers generally (64 Merrill (24.7) summarized the properties of industrial textile fibers. Shedden (28J) gave an excellent report of the performance of a dozen different filter fabrics in sewage-sludge service; Dacron seems most satisfactory. Lucas ( 2 3 5 ) discussed the ammonium content of filter paper. Leppla (22.7) described the size range of commercial diatomite in terms of the minimum particle size removed by each grade. Laboratory Applications and Ultrafilters. In Table V filters and accessories of interest in the laboratory are tabulated along with ultrafilters. Application of the Kozeny-Carman law to filter gauze allowed the adjustment of the fine-particle retention ( 7 7K). I
Literature Cited
Reviews (1A) American Water Works Association Committee 8913P, J. Am. Water Works ASSOC. 48, 787-818 (1956). (2A) Chm. Eng. 63 (No. 13), 164-75, 321,324,331,333 (1956). (3A) Cummins, A. B., Hutto, F. B., Jr., in “Technique of Organic Chemistry,” A. Weissberger, ed., vol. III, Pt. 1, Chap. V, Intencience, New York, 1956. (4A) Hubbert, M. K., J. Petrolcum Technol. 8, Petrolcum Trans. A.I.M.E. 207,222-39 (1956). (5A) Hughes, R. R., Oppenheim, A. K., IND. ENO. CHEM. 48, 633-54 (1956).
(6A) McCabe, W. L., Smith, J. C., “Unit Operations of Chemical En ‘ eerin ” pp. 94-7, McGrawH i r N e w pork, 1956. 7A) Zbid., pp. 324-53. 8A) Miller, S. A., IND.ENO.CKEM.48, 520-6 (1956). (9A) Orlicek, A. F., “Dechema Mono,” Bd. 26, pp. 199-218, erlag Chimie, Frankfurt 1956; Ganic chim. 76,65-74 (1956). (10A) Pratt, C. J., Znd. Chemist 31, 452-4, 607-13 (1955). (11A) Refson, B. H., Chem. Products 18, 411-14 (1955). (12A) Ibid., p. 467-71; 19,17-20,116-18, 1 5 8 6 (1956). (13A Zbid., pp. 23740,326-9, 334. (14AI Singleton, W. A., J. Am. Oil Chemists SOC.33, 477-84 (1956). (15A) Symons, G. E., Water d Scwa c Works 103, 108-11, 151-7 (19565 (16A) Volckman, 0. B., S. Afrrcon znd: C h i s t 9, 149-55 (1955).
$aphien
Theory, Experiment, and Design PERMEABILITY AND CAKE FILTRATION (1B) Brownell, L. E., Gami, D. C., Miller, R. A., Nekarvis, W. F., A.Z.Ch.E. Journal 2, 79-81 (1956). (2B) Gley, F. H., Marsden, S. S., Calhoun, J. C., Produccrs Monthly 20, (No. 8), 29-45 (1956). (3B) Gri orov, 0. N., Novikova, N. A., ffolloid khur. 17,278-86 (1955). (4B) Hutto, F. B., Jr., Annual Meeting, Am. Inst. -Chem. Engrs., Boston, Mass., Dec. 9-12,1956. (5B) Kennedy, H. T., Pfile, R. A., J. Phys. Chcm. 59, 870-3 (1955). (6B) J. F., Goetz, W. H., . . McLaunhh, Hi&av Restarch. Board .Proc. 34. 27k86- (1955). (7B) MacMullin, 1.B., Muccini, G. A., A.I.Ch.E. Journal 2. 393-404 (1956). (8B) Scheidegger, A. E., Annual Meeting, Am. Inst. Chem. Engrs., Boston, Mass., Dec. 9-12, 1956. (9B) Scheidegger, A. E., J. A l. Mcchanics 25, 994-1001 (1958. (10B) Tiller, F. M., Annual Meeting, Am. Inst. Chem. Engrs., Boston, Mass., Dw. 9-12,1956. (11B) Valleroy, V. V., Ph.D. thesis, University of Kansas, Lawrence, Kan., 1956. (12B) Zaks, S. L., Klsakov, M. M.,
Izvcst. Akad. Nauk S.S.S.R., Otdel: Tckh. Nauk 1955, (No. l l ) ,
87-94. APPLICATIONOF CAKEEQUATIONS (1C) Coackley, P., Jones, B. R. S., Sewage and Znd. Wastes 28, 96376 119561. (2C) Hollkd, C. D., Woodham, J. F., Petrolcum Re tlcr 35, (No. 2), 149-51 11958. . . .~ Jones, B.‘R.--S., Sewage and Ind. Wattt~28,1103-15(1956). Marteny, W. W., Olson, K. E., T~@i39,515-17 (1956). Miller, S. A., Carman, P. C., Heertjes, P. M., Trans. Inst. Chm. Engrs. (London) 33, 299-301 11955). \ - . - - I .
(6C) Nickolaus, N., Dahlstrom, D. A., C h . Eng. Progr. 52,87-93 (1956). (7C) Okamura, S., and Shirato, M., Chm. Eng. (Japan) 20, 98-105 11956).
(IOC) Schepman, B. A., Martin, B., Dahlstrom, D. A., Chem. Eng. PrOgr. 52,423-7 (1956). (11C) Sjenitzer, F., Trans. Inst. Chem. Engrs. (London) 33, 289-98, 301 119551. (12C) Werner,‘ E., Z . Zuckerind. 6, 357-9 (1956). CAKEWASHINO AND DEWATERINO (1D) Batel, W., Chem.-Zng.-Tcch. 27, 497501 (1955); 28, 195-200 (1956). (2D) Zbid., pp. 343-9. (3D) Choudhury, A. P. R., Dahlstrom, D. A., Annual Meeting, Am. Inst. Chem. Engrs., Boston, Mass., Dec. 9-12, 1956. (4D) Henderson, A. S., Cornell, C. F., Dunyon, A. F., and Dahlstrom, D. A,, Annual Meeting, Am. Inst. Mining Met. Engrs., New York, Feb. 20-23,1956. (5D) von Rosenberg, D. U., A.Z.Ch.E. Journal 2, 55-8 (1956). FILTERMEDIAAND FILTER-MEDIUM FILTRATION (1E) ‘Bucker, H. P., Jr., Felsenthal, M., Conley, F. R., J. Petroleum Tcchno/. 8, (NO.4), 65-6 (1956). (2E) Oranston, R. W., Beynon, L. R., Aircraft Eng. 28, 318-21 (1956). (3E) Hlefsen, O., Norsk. Skogind. 8, 360-6 (1954). (4E) Zbid., 9, 322-9 (1955). (5E) Gallily, I., J. Colloid Sci. IO, 558-62 (1955). (6E) Grace, H. P., A.1.Ch.E. Journal 2, 307-15 (1956). 1 (7E) Zbid., pp. 316-36. (8E) Hembree, E. E., Tappi 39, 91-3 (1956). (9E) Inoya, K., Yamamura, M., Chem. En , (Japan) 20,163-71 (1956). (10E) Kubft, J., Svensk Papjcrstidn. 58, 175-8, 251-6 (1956). (11E) Steenber , B., others, Zbid., 56, 771-8 $1953); 57, 37-40 (1954); 58, 319-24 (1955); Das Papiet 10,834, 227-32 (1956). (12E) Takiiawa, A., Owashi, T., IuChi, A., J. SOC.Textile and Cellulose Znd. Japan 10,246-9,540-4 (1954).
Equipment (1F) Batd, W., Chem.-Ing.-Tech. 27,743-5 (1955). (2F) Bender, W., Chem. Ind. (Dusseldorf) 8, 358-9 (1956). (3F) Brown, J. G., Chm. Eng. Progr. 52, 238-40 (1956). (4F) Chekan, E. M., S. P. Kinney Engineers, Inc., Carnegie, Pa., pnvate communication, Jan. 3,1957. (5F) Chem. Eng., 63 (No. 2), 234, 236 11956). \-.--r-
Ibid. (No. 71, p. 242. Ibid. (P(.0-.. 11 .- ). DD. 268.270. Ibid. (No. 12), pp. 262,’264. Cronan, C. S., Chem. Eng., 63 ,I
..
(No. 9), 250,252 (1956). ‘ Dahlstrom, D. A., Eimco Corp., Ill.. Drivate communiPalatine. ----, -~~ caticm, Dec. 20, 1956. Cnrn.. Salt Lake City, Utah, Eimco --.= . Bull. B-184. Engrs.’ Digest, 17, 162 (1956). Ertel Engineering Corp., Kingston, N. Y., Bull. EP-1. Fagerberg, B. G . , U. S. Patent 2,735,550 (Feb. 21,1956). Fowler, L. L., Zbid., 2,720,974 (Oct 1% 19551. I
I
Gross,
18,
i i l ~ ~ j .
VOL. 49, NO. 3, PART II
MARCH 1957
491
UNIT OPERATIONS REVIEW (17F) Hercules Filter Corp., Hawthorne, N. J., Hercules Suction Leaf
Filter.
(18F) Hunziku, C. E., U. S. Patent 2,732,079 (Jan. 24, 1956). (19F) Keene, E. W. W., Zbid., 2,717,083 (Sept. 6, 1955). (20F) Kinney, S. P., Engineers, Inc., Carnerrie. Pa.. Bull. 504.4 11956). (21F) Korda, up.,’ Ginit chim. 76, iO9-18 (1956). (22F) Lawlor, J. P., U. S. Patent 2,754,971 (July 17, 1956). (23F) Mies, C. P., Jr., Zbid., 2,760,645 (Aug. 28, 1956). (24F) Mies. C. P.. Jr.. Kracklauer. A. C.. Zbih., 2,760,641 (Aug. 28, 1956). ‘ (25F) Niagara Filters Div., American \ - - - - , -
~r
Machine and Metals, Inc., East Molin, Ill., Bull. NBM-6-56 (1956). (26F) Norden, R. B., Chem. Eng. 63 (No. 7). ,, 314-17 (1956). (27F) Peterson, C. L., U. S. Patent 2,720,315 (Oct. 11, 1955). (28F) Schuller, A. A., Zbid., 2,742,158 (April 17,1956). (29F) Stadelman, R. E., Ibid., 2,754,001 (Julv 10. 1956). (30F) Strindlund; J., Zbid., 2,732,080 (Jan. 24. 1956). (31F) Zbid.,’2,732,081 (Jan. 24, 1956). (32F) Swinton, E. A., Weiss, D. E., Australian J . AMI. ._ Sei. 7, 98-112 (1 956). (33F) Szarejko, R., Gaz. Cukrorvnicza 58, 34-5 (19561. (34F) White, H. W.,’U. S.Patent 2,732,947 (Jan. 31, 1956). (35F) Zievers, J. F., Annual Meeting, Am. \
WATER,SEWAGE, AND INDUSTRIAL EFFLUENTS (1H) Armbrust, H. N., J . New Eng. Water Works Assoc. 69, 287-300 (1 955). (2H) Baylis, J. R., J . Am. Water W o r k s ASSOC. 48, 585-96 (1956). (3H) Bell, G. R., Zbid.,48,1103-24(1956). ( 4 H ) Bell, G. R., Watcr W o r k s Eng. 109, 538-41 (1 956). ( 5 H ) Bell, G. R., Jackson, T. M., Jr., World Oil143,216,218,223 (1 956). (6H) Cosens, K . W., J . Am. W a t e r Works ASSOC. 48. 819-53 (1956). ( 7 H ) Emerson, k. H., - k a t e r - h o r k s Eng. 109,827, 863-4 (1956).
I
Inst. Chem. Enrrrs., Boston, Mass.. DCC.9-12, 195g. . (36F) Zimmermann, M., Food Eng. 28, (No. 7), 54, 55 (1956).
Process Applications MISCELLANEOUS MINERALS, OILS,AND CHEMICALS (1G) Celanese Corp. of America, Brit. Patent 743,046 (Jan. 4,1956). ( 2 G ) Gie, 0. T., Chem. Weekblad 51, 490-1 (1955). (3G) Grimm, R. T., J . Am. Oil Chemists’ SOC. 33, 437-9 (1956). (4G) Heinerth, E., U. S. Patent 2,739,038 (March 20, 1956). (5G) Hertzberg, A. M., Mountfort, C. B., Rush, G., Cunneen, E. W., Proc. Tech. Session Bone Char 1955, 53-82. ( 6 G ) Hess, F. O., U. S. Patent 2,746,607 (May 22,1956). ( 7 G ) Jackson, T. M., Jr., Conference,
Chemical Specialties Manufacturers Assoc.; Washington, D. C., December 1956. (8G) Knoepfler, N. B., Spadaro, J. J., McCourtney, E. J., Vix, H. I,. 33, E., J . A m . Oil Chemists’ SOC. 272-6 (1956).
(9G), McGuire, P. G., Price, H. A., Petroleum Rejner 35 (No. 2), 125-6 (1956). (10G) Macke. R. A..
(16G) Schwer, F. W., Muller, G. W., Jr., Proc. Tech. Session Bone Char 1955, 23-31. (17G) Townsend, F. L., Wm. W. Nugent & Co., Chicago, Ill., private communication, Dec. 14, 1956. (18G) Van Dijck, W. J. D., U. S. Patent 2.758.720 (AuP. 14. 1956). (1 9G) Vilianskii, I.Le, Sakharnaja Prom. 30 (NO.4)) 27-33 (1956). (20G) Wassmuth, H., Austrian Patent 183,965 (Dec. 10,1955). (21G) Yakimov, A. F., Sakharnayo Prom. 29 (NO. 5), 24-7 (1955).
U.
S.
Patent
(8H) Federation of Sewage and Industrial Wastes Assoc., Asso;, Champaign, Ill.. Committee on Research. Sect. A, Sewage and Znd. Waste; 28,617-18,620-23 (1956). (9H) Genter, A. L., Ibid., 28,829-40. (10H) Goidea, D., Rev. chim. (Bucharest) 6,345-9 (1 955). (11H) Hartung, H. O., J . Am. Water Works Assoc. 48. 95-9 119561. (12H) Hudson, H. E.; Jr., ’ Zbid.; 48, 1138-54 (1956). (13H) Meinhold, T. F.! McAnulty, J. F., Chcm. Proccsszng 19, (No. 8), 120,121,125 (1956). (14H) Ritter, J. C., R. P. Adams Co., Buffalo, N. Y., private communication, Dec. 20, 1956. (15H) Sanford, L. H., Gates, C. D., J . Am. W a t e r Works Assoc. 48, 45-54 (1 956). (16H) Small, H. M., Graulich, W. C., Plating 43, 1018-21 (1956). 117H) Smith. R. S.. Cohen. J. M.. Walton, G., J. Am. IQater Work; Assoc. 48, 55-69 (1956). (18H) Wirts, J. J., Sewage and Znd. TVastes 28,121-31 (1956). .
I
(1J) .4nders, H., Textil-Praxis 10, 1006 (1955). (25) Bell, G. R., Chem. Processing 18 (No, 11). 14.15 (1955). Boyer; J.’S., U. %’Patent 2,754,274 (July 10,1956).
Briggs Filtration Co., Washington, D. C., Bull. 905699-A (1956). Briggs, S. W., U. S. Patent 2,746,608 (May 22, 1956). Callinan. T. D.. Materials @ Methods 42, (NO. 6), 98-101 (1955). (7J) Chcm. Eng. 63, (No. l ) , 258 (1956). (85) Zbid. (No. 3), p. 244; Chem. Processing 19 (No. 3 ) , 143 (1956). ( 9 J ) Zbid., 18 (No. 12), 58 (1955).
Butler, G. M., Walworth, C. B., Warren, R. P., IND.ENG.CHEM.
15 (NO.9) 34-9 (1955).
492
1956, 677, 680-2, 716-19.
Guha, S. R. D., Indian Pulp und Paper 10,65-8 (1955).
Hirsch, L., Gloyna. E. F.. SouthWest Water W o r k s 1.38 (No. 3), 15-
24 (1956).
Koupal, R. J., Kalinske, A. A., L- ’5 Patent 2,732,948 (Jan. 31, 1956). Labino, D., Zbtd., 2,728,699 (Urc 27,1955).
Leatherland, L. C., Fzbres (.Vafrcrul and Synthettc) 16 (No. l o ) , 348-3, 367 (1955). Leppla,‘ P. h’., Chem. Eng. Proqr. 52 (No. 4), 41 (1956). Lucas, V., Reu. braszl b r a d farm 36, 233-7 (1955). Xierrill, T. B., .Jr.. .Jr., ,\faterials ‘\faterials h’cthods,42 (NO.6), 119-34(1955). National Filter hiedia hledia Corm. Corp., New Haven, Conn., “New Polyethylene 11
Filter Cloth.” Oliver, D. A., IVilsdon, S. C., U. S. Patent 2,721,378 (Oct. 25, 1955). Rev. Sci.Znstr. 26, 803 (1955). Shedden, W. L., Power Eng. 59 (No. 12). 73-8 (1955).
Va‘lente, JIB., L.S. Patent 2,738,074 (hiarch 13,1956). Wente, V. A., INI).EXG.CheIn. 48, 1342-6 (1956).
Wente, V. A., Lucas, R. I., Ibid., 48, 219-22 (1956). ’ Ciicm.-i7tg. 12-21 (1956).
Zah’, H., &err.
57,
Laboratory Applications a n d Ultrafilters ( 1 K ) Bender, C. E., U. S. Patent 2,728,459 (Dec. 27, 3955). ( 2 K ) Bidwell, R. M., LYykoff, W. R., Thamer, B. J., A’ucleonics 14
(NO. 7), 66-72 (1956). ( 3 K ) Canal, F., Lab. xi. 3, 161-5 (1955). ( 4 K j Chem. Eng. 63 (No. 4), 120, 122, 124 (1 956). ( 5 K ) Engelbrecht, R. S., McKinney, R. E., Sewace and Ind. Tl‘ustes 28.1321-5 (1956). ( 6 K ) Ertel Eng. Corp., Kingston, S . Y., Bull. EL-2. ( 7 K ) Gardon, J. L,., Mason, S. G., Can. J . Chem.
Filter Media a n d Filter Aids
(1OJ) Engrs. Digest 17,361-2 (1956). (11J ) Zbid., p. 407. (12J) First, M. W., Graham, J. B.,
Palkin, N. E., Neftyanoe Khoz. 33 (NO.12), 17-19 (1955). Pashchenko, P. N., Tekstil.’ Prom.
Corp., New Haven, Conn., private commun., Dec. 12, 1956. (155) Great Lakes Carbon Corp., Chicago, Ill., “Nerofil, A Processed Carbon-base Filter Aid.” Grune, A,, Allgem. Papier-Rundschnu
48, 696-702 (1956). (13J) Forbes, W. A,, U. S. Patent 2,725,146 (Nov. 29, 1955). (145) French, R. C., National Filter hfedia
INDUSTRIAL AND ENGINEERING CHEMISTRY
(9K) Hirsch, A . ’ A . . .1..4m. Il’aler Tl’orkJ Assoc.48, 1183--92(1956). (10K) Hiskey, C. F.. Kivert, A. N., Anal. Chem. 28,246--7 ( 1 9.56). (1 1 J ) Konev, F. A,, Kolesnikov.1). G.. ,\led. Prom. 10 (No. 2 ) , 36-40 (1956). (12K) Lausen, H. H., .4cla Pharmacol. Toxicoi 11, 353 -4 (1955). (13K) hfcClung: N. M., .I. Am. Hhter Il’orks Asrw. 48, 781--2 (1956). (14K) Yiack, A. D., U. S . Patent 2,727,632 (Dec. 20. 1956’1. (15K) Razumov, ’ A . ’S., h‘ikrobiologiya 24,234-46 (19%). (16K) Spurn$, K., VandrAEek, V., Chem. list^ 50, 1331 -4 (1956). (17K) Tarrant, W. J., J . Am. Il’atrr 1~’orks~Assoc.47, 1207-9 (1955). (18K) Thomas, H. A,, Jr., LYoodward, R . L., Kabler, P. W.,Ibid., 48, 1391-1402 (1956). (19K) Van Atta, G. R., Guggolz, J., Anal. Chem. 27, 1669-70 (1955). (20K) Willey, L. A,, J . M e f a l s 8, A.l.11l.E. Trans. 206, 263--4 (1 956).
