Α . Ι. Ch. E. Streamlined for W a r supply of those reaching age 18 each year. This small number, insignificant in the total manpower situation, and, in the opinion of many, an absolute minimum for the vast production effort now contem plated, would go far toward ensuring the maintenance of an acceptable level of engineering competence in war production.
S
TREAMLINED for wartime efficiency, the 35th annual meeting of the American Institute of Chemical Engi neers completed its business in two and a half days, without benefit of entertain ment, at the Netherland Plaza, Cincin nati, November 15 to 17. Operation and protection of plants in wartime and urgent problems of procuring and retaining trained manpower to keep industry at peak production under war conditions were the principal topics of discussion, in addition to two sessions de voted to papers on technical developments in chemical engineering. The business of t h e institute, consisting of reports of officers and committees, occupied a short business session. J. L. Bennett, manager of chemical op erations, Explosives Department, Hercules Powder Co., was elected president of the institute for 1943, succeeding S. D. Kirkpatrick. George Granger Brown, pro fessor of chemical engineering, Univer sity of Michigan, was elected vice presi dent. Stephen L. Tyler and C. R. D e Long were re-elected secretary and treasurer, respectively. Four directors elected for three-year terms are: Lawrence W. Bass, director, New England Industrial Research Founda tion; Barnett F. Dodge, head of the De partment of Chemical Engineering, Yale University; Chester L. Knowles, chemical sales director, Dorr Co. ; and Charles M. A. Stine, vice president, E . I. du Pont de Nemours & Co., Inc. Francis J. Curtis, Monsanto Chemical Co., was ap pointed as director by the institute's council to fill the unexpired term of Waiter G. Whitman, resigned. Seriousness of the problem of tech nically trained manpower was recog nized by the institute in voting the pas sage of a resolution directed to com petent governmental authorities, as fol lows: As a part of the professional technical manpower of the Nation, the American Institute of Chemical Engineers, assem bled at its annual meeting in Cincinnati, Ohio, on November 16, 1942, subscribes to t h e ensuing statements concerning the supply of engineering manpower and urges the adoption of the suggestions made therein looking toward the assurance of the necessary supply of men trained on a professional engineering level to perform engineering services in the armed forces and in the war industries. The following are t h e significant facts: 1. The war industries are an essential part of the war effort. 2. The war industries now need and will continue to need a steady replacement supply of technically trained men both for the maintenance of mass production and for the continued improvement of military material. V O L U M E
2 0,
NO.
23»
J. L. Bennett, President-Elect 3. Information from many sources makes it clear that the supply of profes sional engineers of all kinds is wholly in adequate to meet the greatly increased requirements of the armed forces and of war production. The problem is made more acute by the increasing loss of men from industry to voluntary enlistment. 4. The engineering schools must con tinue to be the major source of supply of young engineers. Efforts to enroll women in engineering schools have not yet been successful t o any significant extent. 5. The effect of the new draft law will be t o throw a considerable proportion of all engineering students into officer training programs and a large proportion of those who cannot qualify physically for officers training into the draft. Neither group will be available for the war industries for the duration. I n view of these facts, we strongly rec ommend: (a) That the loss of technically trained men from war production plants be stopped by cessation of voluntary enlist ment or by a "freezing" order covering such personnel and plants. (6) That selective service Occupational Bulletin No. 10 of last June [see CHEM. E N G . N E W S , 20, 837 (1942)] be reaffirmed in principle in its provisions for the defer ment of men in engineering training. (c) That this Directive be modified in the light of the lower draft age by provid ing for the deferment of engineering stu dents in established colleges to the end of the term in which they reach the age of 18, and thereafter, on a term by term basis as long as their academic records remain satisfactory. The present capacity of the engineering colleges for entering students is about 40,000 per year. The number of young men reaching age 18 is about 3,000 per day. Therefore, less than 2 weeks' supply of young men would be sufficient to ensure an output of the normal number of young engineers each year. On graduation the number will have been reduced to about 18,000 and the other 22,000 will have been unsuccessful and will have been inducted into the armed forces. Of the 18,000 trained men, approximately one half would meet the physical requirements for eventual commissioning and the rest would be available for war production industries. As a final result, the armed forces would lose the direct services of only 3 days'
DECEMBER
10,
1942
Reports of officers and committees showed the affairs of the institute to be in flourishing condition. Membership shows a net gain, as of November 1, of 500 over the figure of a year ago. Present membership was reported to total 3,352 of all classes. Added during the year to the list of 44 courses in chemical engineering accredited by the institute were those of seven insti tutions: University of Maryland Northeastern University University of Florida Oregon State College Worcester Polytechnic Institute Bucknell University Cooper Union School of Engineering (now including night course) Despite the absence of plant visits and entertainment, which have usually fea tured meetings of the institute, attend ance of members and chemical engineer guests reached a new high with a regis tration of 430. Although other meetings have shown higher figures for total regis tration, ladies previously welcomed have accounted for a large share of attendance. Operating kinks in wartime provided a subject with which many had had experi ence during World War I. Troubles in converting pyrites burners to handle sul fur in sulfuric acid manufacture, com mandeering of vitreous enameled bath tubs as nitrators in picric acid plants, and troubles with pumping systems designed for water but forced to handle volatile sol vents were among the many topics of in terest to plant operators discussed. Lead ing discussion were Fred. F. Chapman, Albert E. Marshall, and Albert B. New man. Henry Howard and Frederic J. Le Maistre gave some of their experiences b y letter. The problems of skilled man power enter this discussion and remained a dominant topic throughout the meeting. Harvey N. Davis, newly appointed di rector of the Office of Production Re search and Development, WPB, developed the subject further at the informal din ner Monday evening. Seriousness of manpower questions was emphasized by the immensity of demands by both the armed forces (9,700,000 men) and producing industry. The ratio of World War I of 12 men in industry for each man in uniform can obviously not be met now. Also, it seems unlikely that General Hershey's ratio of 4 to 1 will 1555
meet industry's needs. Present terrific drains probably will have grievous effects on our training programs with the con tinuance of war. Protection of plants in wartime was the general topic of four papers forming Mon day afternoon's program. Good housekeeping in plants necessary for their protection a t all times becomes an acute necessity in war with the added hazard of sabotage, according to Lieuten ant-Colonel James C. Sawders, chief, Plant Protection and Safety Branch, C. W. S. In his paper (presented by Major Harry G. Baker, Jr.), Colonel Sawders pointed out the extreme necessity for see ing that all plant services are supervised and all employees identified a t all times to ensure against breaks in production. To normal protection from fire, power fail ure, explosions, theft, and personal injury must be added safeguards against sabo tage, efficient guards against strangers, measures to confine employees to specified areas of work, and provisions for continu ing operation even in blackouts. Separa tion of power lines from lighting lines is es sential for this purpose, as i s a trained staff to supervise operations under blacked-out conditions. Industrial plants can be made far less obvious targets for air attack by applying modern camouflage methods. This phase of the problem was discussed by Greville Rickard, camouflage specialist, Office of Civilian Defense. The objective, the speaker said, is primarily to confuse the bombardier for even a few seconds as he attempts to select his targets. This can be accomplished in a number of ways which tend to break up the large areas of plants and to blend them with surround ings. Selection of the original plant site, plantings of vegetation, painting, in stallation of nets t o break up shadow patterns, and screening smokes are the preferred methods of destroying visually the patterns the bombardier expects to see. Necessarily the effective use of any of these means requires experience and imagination to prevent an effect opposite to that desired. Screening smokes offer effective ways of hiding objects and areas. Modern pro duction of these useful smokes was de scribed by Major Frederick G. Schmitt, Office of the Chief Chemical Warfare Service. Effective smoke screens, which hide areas but need not interfere with activity within them, can b e laid in 8 minutes by modern methods. Thick ness of the smoke screen makes it effective at low density. Criteria in selecting a particular type of smoke are effectiveness of cover, low cost, and harmlessness. Three types are most commonly used: chemical smokes (TiCl4, P206, etc.), carbonaceous smokes, and fogs of oil produced by vaporized oil i n engine ex hausts. Screens can be laid in many ways applicable under varying conditions and are among the most effective means of pro
1556
tection of civilian areas as well as troop movements. Special safety precautions practiced in ordnance plants make them among the safest places t o work according t o Colonel Crosley Field, Safety Branch, Ordnance Department, in a paper read by Major R. C. Stratton. Tables based on experi ence of the Ordnance Department show
Left.
Fred
F.
Chapman. Ε. Ι. du Pont de N e m ours & Co., Inc.
Right. Albert Β. Newman, Col lege of the City of New York.
Left. Greville Rickard of the Office of Civ ilian Defense.
Right. J . L. Bennett, Her cules Powder Co. and newly elected presid e n t of t h e American Insti tute of Chemi cal Engineers.
Left. Albert Ε. Marshall, A g f a A n s c o Division of General A n i l ine & Film Corp.
CHEMICAL
safe distances between quantities of ex plosive materials to be observed in segre gating units within a plant. In addition to this important factor, limitation of personnel and of quantity of explosive material in any particular location to that required for efficient operation is a cardi nal principle of safety. Cooperation be tween operators, Ordnance Department, and the Surgeon General provides special safeguards to the health of workers. A new safety code covering ordnance plants is soon to be issued. A. O. Snoddy, speaking on "Some Cincinnati Industries", traced the rise of Cincinnati from a village, originally called "Losantiville", to its present size and name, obtained from The Society of the Cincinnati. The invention of the steamboat with its attendant power to proceed up the river from N e w Orleans to Cincinnati was one of the biggest contributions to the growth of the city. Before the advent of steam power early industries were based on agriculture and its products. Power, available as it was with these engines, made a difference in the industrial pic ture and soon factories were displacing the home industries. B y 1819 the city had grown to an area of 3 square miles with 1,890 buildings, and 214 shops, 10 churches, and 17 taverns. There was also a tre mendous (for the time) steam mill of 70 horsepower which furnished power for four millstones and a textile mill. I t con sumed 480 tons of coal a year and Mr. Snoddy compared it with modern Cin cinnati power plants using about 600,000 tons per year. The Cincinnati soap in dustries were early playing a part in the city's prosperity. In 1837 William Proc ter and James Gamble pooled their savings of $7,500 and began the business which is today the massive Procter & Gamble Co. This firm grosses annually $282,000,000 and its Cincinnati plants occupy ap proximately 200 acres. Mr. Snoddy con cluded his paper with examples of soap advertising from the years 1850 and 1937 and showed how little the advertising message has changed during that period. F. J. Gradishar, W. L. Faith, and J. E . Hedrick reported on work done at Kansas State College on laminar flow of oil-coal suspensions. This investigation, part of a larger program on manufacture and cost of colloidal fuel, was made in order t o determine friction losses in pipes carrying the colloidal fuel mixture. It was found that suspensions of coal in fuel oil may exhibit either viscous or plastic flow depending on concentration. However, at a definite concentration of suspended matter the mechanism will b e transformed into plastic flow and the fluid will possess a definite yield value which must be overcome before flow be gins. The critical concentration was shown to correspond to the concentra tion a t which the particles just touch each other to form an arch capable of resisting
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NEWS
Left to right: Top. S. C. Kirkpatrick, Chemical & Metallurgical Engineering, and retiring president of the American Institute of Chemical Engineers; O . R. Sweeney, Iowa State College, and J. Howard Arnold, University of Iowa; Henry N . Lyons, Cities Service, and A . E. Marshall, a past president of the institute, with Harvey N . Davis, Office of Production Research and Development Center. C. R. De Long, treasurer, and R. P. Kite, Dorr Co.; Ernest M . Symmes, Hercules Powder Co. with Stephen L. Tyler, secretary; and Warren L. McCabe, Carnegie Institute of Technology, with J. L. Bennett, newly elected president of the institute. Bottom. George G . Brown, newly elected vice president with J. L. Bennett; M . H . Ittner, Colgate-Palmolive-Peet Co. and George G. Brown; Gaston Du Bois, Monsanto Chemical Co., D. B. Keyes, WPB, Norman W. Krase, du Pont Co., and R, L. Murray, Hooker Electrochemical Co.
slight pressure. The concentration at which zero fluidity occurs as a fluidityconcentration plot was practically iden tical to the critical concentration. An equation was formulated for suspensions of 200-mesh coal in oil up to 40 per cent by weight which enables the prediction of friction losses. Ή. P. Simons, Joseph Ή. Koffolt, James P. Withrow, and Richard J. Mitchell collaborated in a ponderous report on the drying of rayon—both cakes and skeins. The data presented were the results of 17 years of intermittent studies and experi mental work on the effect of various dry ing conditions. The first report covered rayon skeins and after a description of the dryer and technique used in obtaining the varied, data, the authors summarized their re sults as follows: Suitably centrifuged rayon skeins were observed to dry solely under falling rate conditions and found to conform to the equation, —dW/d0 0.78G1··1 (ΔH)W, where dW/d0 - rate of drying, pounds of water evaporated per pound of bone-dry stock, G — mass veloc ity of air, pounds per minute per square
foot, ΔΗ = humidity corresponding to the wet bulb temperature of the air, pounds of water per pound of bone-dry air, and W = free moisture content, pounds of water per pound bone-dry stock. The critical mois ture content of 150 denier, 40filament,spool processed yarn averaged 0.98 pound of water per pound of bone-dry stock. Dry ing at temperatures up to 200° F. and humidity conditions in line with indus trial practice had no measurable effect upon the degradation properties of the yarn as evidenced by wet tensile strength, elongation, copper number, sodium hy droxide boil test, dye test, and cuprammonium disperse viscosity. Drying for prolonged periods at high temperatures, however, had a slightly degrading effect upon the yarn, but this was evidenced only after unnecessarily long drying periods. In conclusion the authors stated that the safe drying temperatures re corded in literature were probably too low and increased dryer production could probably be obtained by use of higher tem peratures. The work on drying rayon cakes was done on 150 demer, 40 filament rayon
VOLUME 2 0, NO, 23 > DECEMBER 10, 1942 +
cakes of viscose pot production. A dif ferent equation was found to hold for drying viscose cakes: -dW/d0 = 0.88G1.05 (ΔH)W Again it was found that drying air tem peratures and other conditions had no noticeable effect upon the rayon. As part of a program to obtain more data for design purposes on liquid-liquid extraction, Olaf Bergelin, Frank J. Lockhart, and George Granger Brown pre sented a comprehensive report on data obtained from a study of the ternary sys· tem tetrachloroethylene-isopropyl alcoholwater. Physical properties including equilib rium relationship of the liquid system at 77° F. were determined. The effect of velocity of the phases upon the flow conditions was shown by photo graphs. It was found impossible to esti mate the turbulent characteristics of flow by any orthodox use of Reynolds number, since the velocity distribution in one phase is determined by the flow properties of both phases. When mass velocities of 1557
the phases are equal in magnitude the interfacial velocity approaches zero, which creates a stagnant film in each phase and aids in the accumulation of foreign materials at the interface and the transfer coefficient passes through a minimum point. A process to remove 88 per cent of the lime in sugar manufacture formed by the addition of sulfuric acid to the molasses, was claimed by G. T. Reich of the Pennsylvania Sugar Co. The calcium sulfate contaminates the yeast, forms scale in the beer still and slop evaporators, and prevents profitable recovery of by-products from the slop. Mr. Reich's new method is said to give the first positive method of removing this unwanted material. Briefly, the process consists of mixing molasses with a stream of hot water and then passing the mixture to a proportioner which regulates the ratio of molasses to sulfuric acid. This mixture enters the top of a reaction tank where it is heated; the molasses settles continuously and discharges into centrifugals. The clear molasses liquid discharges from the top of the centrifugals while the calcium sulfate and other organic materials are caught in the bottom of the centrifugal basket. This collected sludge is mixed with hot water, discharged into a receiving tank and then into a baffled settler. The separation of this sludge is said to give an increased quality and quantity to all the further sugar processes, especially in the yeast produced and the decreased amounts of calcium scale in the stills. J. A. Gerster, of Tulane University, and J. H. Koffolt and J. R. Withrow collaborated in an investigation on the extension of Chilton and Colborn's HTU method to plate columns. The authors introduced a new concept, the (PTU)ov which is the number of plates equivalent to a transfer unit and similar to the HTU expression, inasmuch as it is expressed by
(PTU)ov = NP /
I y2 - j ^ -
I Jy1
y
~y
where NP is number of plates, y1 and y2
1558
composition of vapor entering and leaving columns, and y* and y the mole fraction of volatile component in liquid and vapors. A plot of PTU against the slope of the vapor-liquid equilibrium curve gave a simple correlation of results at constant vapor velocity. The authors claimed the existence of a liquid concentration gradient across the plate of a bubble cap and that this method i s a logical basis for evaluating still performance, optimum plate spacing, optimum velocity, diameter, and number of bubble caps per plate. Further work is being done. George Granger Brown and Frank J. Lockhart of the University of Michigan, reported on the effect of vapor load and efficiency in fractionating columns. This work was undertaken to relate available laboratory data to commercial operations. It was found that the over-all plate efficiency for laboratory columns is largely independent of the mass vapor velocity over a wide range of normal operation. At abnormally low vapor velocities the plate efficiency decreases very slowly in the laboratory columns and quite abruptly in the commercial columns. The principles of stripping were investigated in a treatise by Harold J. Garver, of the University of Cincinnati, and Frank Lerman, of the Blaw Knox Co. Stripping operations, they said, possess the advantage over straight distillation of the volatile components from liquid solutions in that more complete separation can be obtained a t lower temperatures for the same conditions of pressure or vacuum. In view of this and the number of uses of stripping operations in industry, the authors undertook to assemble the pertinent data now in the literature. T h e y compared batch and continuous stripping and showed theoretically that the same operating conditions, irrespective of the phase behavior, consumed more stripping medium in a batch process than in a continuous countercurrent system. A graphical method was given which allowed the easy determination of the number of actual plates required for a continuous plate stripping column. A new type of rectifying column for use
CHEMICAL
in conjunction with high vacuum stills was discussed by Robert M. Schaffner, of the Standard Oil Co. of Indiana, John R. Bowman, of Mellon Institute, and James Coull, head of the Department of Chemical Engineering at the University of Pittsburgh. The new column is a vertical tube having alternate heated and cooled segments. In operation the vapor from the still rises through the tube and mixes with the alternate zones of vapor created when the reflux flowing down the tubesides is vaporized by the heated segments. At each cooled segment, portions of vapor are condensed and join the main reflux stream. The column thus has an alternate action in stripping out light components and condensing heavy portions. The still described in the paper was constructed of a glass tube 1 to 5 inches m diameter and 5 feet long. It was provided with 12 heated zones separated by 12 cooled zones. Each section of varied temperature was 2 inches long. Heat was supplied by power through Nichrome windings, the sections being covered on the outside with asbestos. Cooling was effected by jets of compressed air. In operation, the column reflux rates were measured by an optical glass gage by estimating, through proportion, the thickness of the flowing reflux film. The film thickness could be read to 0.001 inch, and reflux flow rates, through the constant of proportionality between flow rate and the cube of film thickness, could be calculated to within 5 per cent. The column was run at 0.1 to 0.01 mm. of mercury and throughput was 250 ml. per hour. As is to be expected, tests of the column indicated that an increase in vaporization condensation action increased the separating power of the column. The present column, however, is not so dependent on high reflux as the conventional types. As the reflux ratio was decreased from infinity the new column improved when compared to a column of theoretical plates operated at the same reflux. Efficiency increased rapidly as the volatility ratio of the materials separated decreased toward unity, indicative of a high suitability for rectifying mixtures difficult to separate.
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NEWS
