MARCH 1952
I 1
PAPERS I N T H I S
ISSUE
1xm-I-IIyDUSTRY COLLABORATIVE REPORT
On the basis of over 20 yean of their own research and extensive study of German experience, the United States Bureau of Mines has built a demonstration plant for the production of liquid fuels from coal by the gas synthesis proceea commonly associated with the names Fiseher-Tropsch. The plant is of the minimum aimthat will give p e r f o F c e data chmcteriStic of a commercial type operation. Thii year the unit has made its first complete m. hlveriaed coal is gaai6ed with steam and oxygen to produce a synthesis gas which reacts in a “jiggling bed” catalytic reactor cooled by concurrent Bow of heavy oil. Capacity is 50 to 80 barrels per day and conversion &ciency about 80%. The data are now available on performance under various operating conditions. When these data have been analyzed and other operating variables have been investigated it should be possible, for the 6rst time, to d e specific statements about the economic feasibility of the prcduction of synthetic fuels in the United States.
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AN AMERICAN FIECHERTROPECA PLANT 1. K u U , 1. L. pnt ul R. 0.
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460
SYMPOSIUM:OM LIQUID INDUSTRIAL WAbTEP
A comprehensive program on the nature and present status of liquid wastes diapoml problems in representative industries in the United States plus a summary of the situation for similar industries in Great Britain was o r g a n i d for the 75th Meeting of the ACS in New York last September. Most of the papers presented at the meeting are published thia month; they furnish an up-to-date progreas report on research, processe%, and equipment related to the treatment and d v a g e of wastes. Disposal problems q u i r e coatant attention even in tanneries, packinghouses, &ea, and steel mills which have had long experience in the treatment and u t h t i o n of their wastes. Newer industries such as atomic energy and antibiotics have recogniaed the necessity of studying wastes, sometimes before planned pmduction has reached the pilot plant stage. LIQUID INDUSTRIAL. WASTES..
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.IC1
GENERAL PAPERS R u e l3arlh Rd~actian
The presence of a large quantity of rare earths in the &ion products of atomic piles has increased the interest in these elements and occasioned the need for quantiti& of pure rare earth metals to permit accu.rate determination of some of their properties. A method of pmparing pure rare earth metals in the maasive state has been d e viaed, in which anhydrous rare earth chlorides are reduced by calcium in refrsctory oxidelined containers. Iodine is added to the reaction mixture, and by its highly exothermic reaction with calcium liberates sufficient heat to give a well-fused m w of product metal. Vacuum remelting removes all but trace amounta of calcium. Kilogram quantities of lanthanum and earium, and smaller amounts of praseodymium and neodymium have been pmdueed, all p u m than 99.7%. In addition, over lo00 pounds of 95 to 99% cerium have been prepared by the prooeas dwribed. Pure d v e samarium and yttrium metal were not obtained by this technique.
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PRODUCTION OF PURE RARE EARTH METALS
RuLP.~,Pu~A.W-,W.-P.-.r.I
442
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
683
Vol. 44, No. 3
L-tlng
Onur fa Uigh Temperatwo 0.raciOru
The increased operating temperatures possible for electric motors insulated with silicone resins has created a need for a gmase which will lubricate hall bearingsa t 200' C. or above. The soap phase of ordinary or of silicone greases deteriorates within a very short time at thii temperature. Phthalocyanine pigments have been shown to form greases from petroleum oils, silicones, aliphatic diesters, polydkylene glycol ethers, and fluorocarbons. These greases contain SO% or more of liquid by volume and maintain their structure to above 300' C. They are water resistant, shear stable, and less susceptible to oxidation than corresponding sosp greases. Phthalocyanine pigment is not abrasive. Phthalocyanine-gelled silicone greases have lubricated ball bearings for 10,ooO hours a t 80" C. and for as long as 900hours a t 220' C. Special alloy steels are necessary in bessings operating at 20O0 C. or above. The development of greases useful at 200' C. permits the redesign of electric motors with large economies in space, weight, and critical materials. PHTHAWCYANINE LUBRICATINQ QREASES I.y..Lr,4cuu.E slnsIdomY vtrart 0.,-IP
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Vui.Lk. Affoctlng W a k Ildsta~~am of ha-
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Organic surface coatings containing combinations of alkyd and nitrogenous resins m applied as baked finishes to one billion square feet of metal monthly. A frequent sonrce of early failure of these coatings is believed to he a weakening of the films due to contact with water or water vapor. A study was undertaken to determine the e5ect of the nitrogen rcein, the &yd resin, the curing conditions, and . the pigment on the wabr resistance of baked 6nishes. It waa found that the baked finishes are w t l y merent and much weaker when wet than when dry. The films lose adhesion and tear strength but gain in flexibility. Upon redrying most strength properties return approximately to their initial d u e . Adhesion, however, does not return, and, when once lost, is not regained. The alkyd resin is generally superior to the nitmgen resin, nonoxidizing alkyds are better than oxidizing, the longer curing schedules are detrimental, and zinc oxide as a small portion of the pigment is beneficial. A better insight baa been obtained of the role played by the variables studied on the water resistance of nitrogen &-containing baked alkyd finishes. Improved organic coatings should result.
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WATER RESISTANCE OF COATINGS CONTAINING NITROGENOUS RESIN8
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Sodium Th-ak
The yarious sodium metaphosphates which today find wide industrial use are generally prepared by the thermal dehydration of sodium dhydrogen orthophosphate. The surprising observation that the low temperature hydration of a-phosphorus(V) oxide p r o d ~ c echiefiy ~ tetrametaphosphoric acid (H,P,O,J has led to the development of a simple procedure for the preparation of sodium tetmetaphosphate. The sodium salt crystallizes from solution as the IO-hybte below 25' C. and as a 4hydrate at higher temperatures. The anhydrous salt is obtained by dehydration at about 100" C. The tetrametapbosphate ion undergoes rapid hydrolysis in alkaline solution to orthophosphate and tripbosphate; it yields no precipitates with cupric, mercuric, zinc, and mercurous ions but does precipitate lead and barium partially. Unlike the so-called hexametaphosphate, it does not behave as a sequeatering agent. A mechan'sm for the bydiation of a-phosphoruaCa) oxide, based on structural considerations, is proposed to account for the formation of tetrametaphosphoric acid. Suggested applications depend on the ability of sodium tetrametaphosphate to precipitate proteins and to serve as a source of triphosphate ions in alkaline solutions. PREPARATION OF SODIUM TETRAMETAPHOBPHATE
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Evaluation of Ilydmcubom TIpn a d NapL1Lu 6-
The development of a chromia-alumina catalyst for naphtha reforming, using a single naphthg, has been described. Further rceulta of catalytic reforming of naphthas of different composition and source are of interest to the petroleum industry in the selection ofnaphthas for reforming. Experiments have been conducted on the preparation ofmotor gasoline, aviation blending stocks, and pure aronatic compounds from naphthas of s e v d blending stocks and pure aromatic compounds from naphthas of several typical crude oils and from mixed StmighGrnn and cracked naphthas. Variation in yields of as much as 15 volume % ' at constant octane number has been found. The reformhtes obtained show good stability and are almost completely d d u r i z e d . March 1952
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
The variation in yield has been found to correlate with the Wahn-Nelson K factor, paraffinicnaphthas giving lower yields, which makes it possible to select naphthas for optimum yields. COCELLED CHROMIA-ALUMINA CATALYSTS FOR NAPHTHA REFORMING
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The observed grater mistance of dum GRS polymer to oxidation suggested an investigation as to the caw,and to determine if certain other metal d t s would give simiir results. Coagulation of G W with salts of aluminum, sodium, magnesium, calcium, zinc, and lead impart8 protection to G R S polymer in varying degrees. Only aluminum and zinc were without detrimental effectsin the wlosniaates. Copper, cobalt, and iron promote oxidation in both polymers and vulcanizstes. The beneficial effect is attributed to the formation of a metal soap which is adsorbed on the surface and retards *ion of oxygen into the rubber particle. Even copper and iron maps may impart protection under certain conditions, but once the protective layer is broken, t h e e metals promote the oxidation reaction. The Merenoes induced in Hevea and GRS polymer by the me of various coagulants are much less apparent after vnlcanization. OXlDATION OF HEVEA AND GR-S POLYMER8 AND THEIR VULCANIZATES. EFFECT OF VARIOUS COAGULANTS n . v . ~ u ~ ~ lwuh ,, .ar ~ lw ~ ~.l
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The present study was undertaken in order to establish the function of carbon black in cementa for adherim rubber to metal. Cements containing G R S and ca;bon black a s the msj, constituents considerably inc*w adhesion of rubber to brass and to steel coated with I various resinous primers, provided the carbon black is strongly flocdated. This is ascribed to the chemical activity of the carbon black as revealed by recent work on the nature of the carbon black surface. More thorough dispemon of the carbon black leads to wetting by the polymer of the carbon particles with a c c o m p n k blocking of active centers capable of producing adhesion to the substrate. Of the functional organic p u p s known to be present on the carbon black surface, those responsible for the acidic pH of the channel and color blacks dm appear responsible for a major portion of the adhesion. The results of this investigation suggest the pssibfity of utilizing the surface activity of pigmenta in muring adheeion in applications other than rubber to metal bonding. They ala0 show that the &ate of dispemion of the pigment must be expected to be an important variable in any such application.
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CARBON BLACK FLOCCULATION IN RUBBER TO METAL CEMENTS
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The investiition was undertaken to simplify the design and construction of an alternate immersion comwion test eqnipment. The charaderistie f e a t m of the new desi@ am the hanging of the specimen in a horizontal p i t i o n to ensure eqnal duration of immersion of all parts of the specimen in a corrosive medium, and the continnous up and down movement of the specimen to deet even distribution of corrosion conditions over the e n t i i sample. Glasa sewing thread was found most satisfadory for supporting specimens, for it resists the attack of acid, alkali, and d t solutions. Becaw of ita simplicity of construction, the new equipment costs substantially lega than older types. Several series of corrosion testa on titanium, aluminum, and stainless &Is indicate that the reproducibility of experimentalresnlts, expressed as percentage deviation from average values, is in the range of 1 to 7%. ALTERNATE IMMERSION CORROSION TEST EQUIPMENT. IMPROVEMENTS I N DESIGN
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A constant liquid feed device was needed in investigations of gas phase chlorination. The device described was adopted after others had proved deficient in accuracy or excessively laborious to construct. The apparatus is easily fabricated, adaptable to a large range of flows, suitable for most liquids, and adequately mcurate for the intended use. I t is suituble for ngulation of flow of clean liquids from a few drops per minute up to the fastest flows encountered in customary laboratory work.
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CONSTANT LIQUID PEED DEVICE A.11.P.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
5.
Vd. 44, No, 3
Salable Refhad Prodnet.from Shale Oil
Hydrogenation has been investigated as a means of removing nitrogen and sulfur compounda from shale oil. Hydrogenation of the total crude shale oil at 3000 pounds per square inch gage over a fixed-bed catalyst consistingof nickel sulfide'plus tungsten sulfide gave satisfactoryoperation and catalyst life with a minimum production of gasoline and other low boiling components. Nitrogen removal was about 95% complete with a hydrogen Consumption of a b u t 1800cubic feet per barrel of shale oil. The hydrogenated shale oil yield was over 100 volume % in all cases, with considerable improvement in odor and color. Additional color stability of the distillate products was obtained by means of a light acid treatment with little loss in yield due to the high degree of fatuistion of the hydrogenated product. Shale oil may be used to extend the crude petroleum supplies of this country. The hydrogenation process serves as a meaus of pmducing from shale oil in high yield a synthetic crude oil amenable to further proeeasing in conventional petroleum equipment. When compared with similar products from the untreated crude shale oil, products made from the hydrogenated shale oil require less treating for finishing and undergo lower treating losses. HYDROGENATION OF SHALE OIL W.Y~~,T.C.-,ulO.E.PLillic
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olu Vdrw fox Plow C0nh.l Laboratory devices such as stopcocks and pinchcocks are often unmtkfactory for controlling small rates of flow of fluids with sufficient accuracy. The glass valve described embodies the major design features of ordinary metal needle valves which have satisfactoryflow-eontrol characteristics. Flexible tubing sewes as the packing. This type of valve can be used where repmducible and steady flows are required in the laboratory and where extreme resistanceto corrosion is necessary. CONTROL OF SMALL LI UID FLOW8 USING GLASS VALVES
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The equilibrium characteristics of the system 8-soluble anhydrite and moist air were studied in order to make available data necessary in subsequent studies of the kinetic mechanism by which moisture is sorbed. Equilibrium data, particularly in the low humidity range, have been inadequate. It was found that at m m temperature the system under considerationexhibited zeolitic behavior below 1% relative humidity. Between 0.409 and 30% relative humidity the desiccant resembled a crystalline solid with a decomposition pressure in the range of 0.409to 1.0% relative humidity. I n the range of 0.409 to 30% relative humidity it slso exhibited zeolitic behavior with a maximum moisture concentration corresponding to the hemihydrate. Above 30% relative humidity adsorptive capacity 1 u ~ egradually toward the dihydrate. The e5ects of repeated regeneration and varying the regeneration cycle were a b studied. The results m of general interest to t h w engineering air conditioning, wind tunnel, metallurgical, and other installations requiring a desiccant with high e5ciency-low capacity characteristics for finish drying. STATIC SORPTION ISOTHERM FOR 680LUBLE ANHYDRITE AND HUMID AIR
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Ak odl.(iorof Ilydmcubou Although the catalytic VaFr-pbase oxidation of hydrocarbons, using air as the oxidizing agent, is attractive economically, relatively few hydrocarbons have been oxidized successfully in this manner on a commercial scale. In order to extend the range of application of the process, quantitative information on the effect of hydrocarbon structure, catalyst type and structure, and o p e r a t i conditions on the types and amount8 of products formed, has been obtained for several four-carbon hydrocarbons. Although the oxidation of ethylene with a silver oxide catalyst leads to amounts of ethylene oxide comparable to those reported in the literature, only traces of intermediate products m found when the four-carbon hydrocarbons m passed over the same catalyst. Appreciable amounts of intermediate products result when a vanadium pentoxide catalyat ia used. With this catalyst the oxidation of butadiene leads to maleic acid, formaldehyde, and glyoxal. These products and, in addition, acetaldehyde, m t i c acid, and methyl vinyl ketone result from the oxidation of 1-butene and %butene. With the W i b l e exception of methyl vinyl ketone, these products are also found in small amounts in the oxidation of nbutane. The oxidation of isobutylene leads to acetic acid, emethylacrolein, and formaldehyde. Madl 1952
INDUSTRIAL A N D ENGINEERING CHEMISTRY
Yields and conversions at various air-hydrocarbon ratios, teniperatures, and contact times ais reported and the results are discuswd. The products found in the vapor-pbase oxidation of four-carhon hydrucarhons over a vanadium pentoxide catalyst can, for the most part, be explained by a scheme of atomic dehydmgenation and peroxidation followed by peroxide decomposition.
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CATALYTIC VAPOR-PEAW3 OXIDATION OF SOME FOURCARBON HYDROCARBONS an.-,anrr.w-,dB.r.u
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cankt*.a4 Data on Rapame-Rupdem 8Reliable vapor-liquid equilibrium data for the propane-propylene system are needed for the design of fractionation facilities for the scient reumxy of high-purity propylene. Three isotherme (25.5O, 82.7O, and 134.9O F.) and one isobar (332.5 pounds per square inch absolute) weredetermined. Thwdata,alongwith theBvebthermsbetween1O0and 191°F.mtablishedbyResmer and Sage, which became available while this experimental work was in p r o m , have been correlated. The method of cordation in based on theoretical considerations. A set of eight smoothed plzy curves which are mutually consistent in presented; there is good agreement between the smoothed curves and all the experimental data. The separation of propylene and propane is important industrially. In addition to reporting experimental data, this paper presents a correlation which is an important contribution to the literatu1s in thia h l d . In general, high-pressure vapor-liquid equilibrium data are correlated empirically. Correlations that m theoretically sound are usually correlationsof data for only one isotherm. The correlation of high-pressure equilibrium data for eight isotherms based on theoretical considemtions is a significant dewlopment.
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PROPANEPROPYLENE SYSTEM. VAPORLISUID EQUILIBRIUM RELATIONSHIPS c.a.-,R.I.-, W.T.N.h,amd .R.-
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A knowledge of the characteristics of mixtures of water and the lighter hydrocarbons is of interest in estimatmg the behavior of petroleum in underground rescrvoh, where it is usually in contact with water. The composition of coexisting phases of the n-butane-water system in a two-pbw region made up of an aqueous liquid and a gas phase has been established at temperatures from 100' to 460" F. and for pressures up to 10,000 pounds per square inch. Throughout the same range of temperatures and pressures the influence of pressure and temperature upon the molal volume of one mixture of n-hutme and water has been determined. The r d t s are presented in graphical or tabular form. The n-hutane-water system in the gas phase of a heterogeneous gas-aqueous liquid region yields a much more complex variation in composition with pressure than is encountered in the methane-water or the ethane-water system under similar conditions. This greater complexity apparently results from proximity to the thee+me region. The solubility of n-butane in an aqueous liquid phase increase markedly with a rise in temperature ahove 100'' F. for pressuree above 750 pounds per square inch. These data contribute to the understanding of efTect of water upon the phase behavior of the lighter components of petroleum.
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P U E EQUILIBRIA I N HYDROCARBON SYSTEMS. +BUTANEWATER SYSTEM I N TWO-PHASE REGION E. E. ,..E. W , d W . N . La-
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p,olorna Recent growth in the industrial importance of the phosphoric acids has heightened the significance of information on the properties of the system P,OlrHX). To amplify and extend this information, the pressure, composition, and density of the vapor were determined for phosphoric acids containing 61.6 to 92.7% P,Olo. Boiling points from the vapor preeaure measnrements were combined with data from the literature in the construction of a boiling pointcomposition curve for the range 0 to 92% P.0,o. An approximate vapor composition curve was oonstructed to complement the boiling point curve. The existence of an amtropic mixture containing about 92% P40,0and boiling at about 866' C. (1atm.) was confirmed. The apparent molecular weight of the vapor at 1020' C., as determined by the Victor Meyer method with acids containing 61.5, 72.4, 88.0, and 92.0% P,Olo, indicated that the molecular species in the vapor phase were P,Oio and €I&. The resnltsof the study are applicablein the design of plants for producing phosphoric acids of high P,Ol0 content, in certain proceases where the acids serve &s catalysts, and in thermodynamic calculations involving the acids.
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VAPOR PRESSURE OF PHOSPHORIC ACIDS &lE..Lnn d c r l L r D.
446
INDUSTRIAL A N D E N G I N E E R I N G C H E M I S T R Y
B15
Vol. 44, No. 3
Tanu). P k w Eldllb.L
This investiiation is one of a series to determine ternary liquid-liquid phase equilibria for alcoholalcohol-water and alcohol-acid-watersystems. tie line data are presented for the ternary system heptsdecanol25O and 50’ C. and for the ternary system heptadeeanol-waterThe estimated plait points for the a c i d - c o n t s i system occur % acid at 25. C. and 64.0 weight % acid at 50’ C. The alcohol point occurs at 56.8 weight % ethanol at 25’ C. In general, the area is smaller for the alcohol-alcohol-water system than for the acid-water system, showing greater mutual solubility. The relative miscibilities of the two ternary systems indieate a slightly m t e r a%ty of the higher alcohol for ethanol in the presence of water than for acetic acid.
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LI UID LIQUID E UILIBRIA. AEPTADECANOLWATEEACETIC ACqD n N D HEPT%ECANOLWATERETKANOL I-“ c. uw-ub and y.ttL.r v u wlmhh .*I8
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This investigation is part of a series to determine the vapor-liquid equilibrium characteristies of hydrocarbon binary systems of h i h boiling point. Vapor-liquid equilibria were determined on the dodeoane-hexadecene system at pressures of 10,20,50, LOO, 200,400,and 760 mm. of mercury absolute. zy data and experimental activity c&cient data are ,resented. This investigation and others of the series expand the knowledge of the vaporization characteristics of heavy hydrocarbon mixture under vacunm, and enables better design of vacuum distillation equipment.
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VAPORLI UID EQUILIBRIA AT SUBATMOSPHERIC PRESSURES. SYSTEM DODECANEAEXADECENE I& m. and nmv u Whhb... ...............................
ENUINEERIAIQ AND ?ROCESS DEVELOPMENT
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An attempt was made to see whether natural impurities in benzene, or agents added to benzene, could improve the extraction of acetic acid from benzene drops by watez Such results might help explain the mechanism of extraction. Benzenes of various origins and purities which had been passed through the same feed system contaiiing Tygon tubing all had essentially the m e low extraction e5ciency. The addition of a few per cent of many alcohols greatly improved the extraction in both tall and short spray towers, possibly by destroying interfacial barrim set up by impurities extracted from the Tygon tubing. The highest alcohols were indective. while the lowest were rapidly extracted by the water. The extraction during free rise has been compared with results of similar investigations with acetic acid and various solvents by means of “transient lilm” equations. Thef. correction factora required range from 0.044 to 0.089 for benzene, toluene, and carbon tetrachloride when fed through Tygon t n b w to 0.62 to 0.90 for many polar solvents. The better additives make the benzene approach the performance of the latter solvents. The danger of poisoning nonpolar solvents by Tygon tubing has been pointed out. Means are offered for improving the extraction in such poisoned systems. The interpretation of the d t s in terms of trausient films illuminate the basic mechanism of transfer.
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DDITION AGENT8 AND INTERFACIAL BARRIERS I N LI UIIhLIQUID EXTRACTION had.. W ~ , A . .I..nmu, A . T . C L . I . , a n d L . E . X . ~
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The removal of filtrate from filtercakes by “washing” with water or weakliquor an important operation in filtration. However, very few data and no general relationships have been reported in the literature. In this article data are presented and general relationships are developed for estimatii the removal of filhte by wash liquids miscible with the filtrate. The mechanism of washing can be divided into three stages: displacement terminated when a portion of the wash first emerges from the filter cake; flow of both liltrate and wash from the cake; and ditrusion of final traces of filtrate from theintersticesoftbecakeintothewashstream. The size of particles in the filter cake, viscosities of wash and filtrate, relative volume of wm March 1952
INDUSTRIAL AND ENGINEERING CHEMISTRY ~~~~~
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~~~~
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447
relative cake thickness were found to be important variables. Particle shape, porosity, and rate of wastiing hadlittleeffecton filtrateremoval.
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WASHING I N POROUS MEDIA a.s.4L. E.
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111
E.tL..(iry C ~ t o s X . P h i a P e r ~ ~ c e
The adoption of chromat&aphie procedures for separating high-cost proceas materials industrially bas been impeded by an inability to identify the pertinent operating variables. This paper seeks to establish a rational framework for interpreting Iahoratory results and for scaling them up. The concentration history of an ion follows “linear” kinetics when its maximum concentrations in solution and on an exchange resin are below 10% of the concentration of a carrier ion. With a limited feed charge, the elution curves for any “trace” ion fit Gaumian equations of the type:
where 8 is a diffusional column-capacity parameter, related to equilibrium stageJ or to NTU. The group sd,,/h is correlated with Reynolds and Schmidt groups, in order to predict the optimum design conditions. Chromatographic performance can thus he estimated from equilibrium measurements and hasic physical data. The design procedure is illustrated for a W i h l e radium-barium separation. ION EXCHANGE CHROMATOGRAPHY OF TRACE COMPONENTS. A DESIGN THEORY
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The importance of a knowledge of non-Newtonian flow is increasing because of the common occurrence of complex materials in chemical industry. The present work was undertaken in order to 6nd a quantitative way of dealing with the Bow of one common kind of non-Newtonians, so-called plastic materials, exemplified by thick suspensions. On the basis of the principle of similitude and data reported in the literature, a simple criterion is derived, which distinguishes between laminar and turbulent flow of plastics in long, straight and smooth, cylindrical pipes. It is found h t for turbulent flow the usual Fanning friction factor cume of Newtonians is at leaat approximately applicable also to plastics, if the Reynolds number is defined as DVp/pp, pp being the plastic viecosity. Curves and a nomogram are given, permitting accurate calculations of preasure drops in a straightforward, simple manner.
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FLOW OF PLASTIC MATERIALS I N PIPE8
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P d Stedimtion The object of this work is to promote and expand succeasful applications of a heat transfer apparatus of special deaign in the food proceasing field. The apparatus makes poasible the continuous heating and/or cooling of many products under rigidly controlled conditions of temperature and p r e m u ~ . The over-all heat t m f e r coefficients are greater than those obtained with heat transfer equipment operating on dserent principles. Details of the apparatus as employed in the chillingand plasticizing of lard, shortening, and margarine, and in short timehigh temperature sterilization are given. The heat exchanger discussed has been proved to be ideally suited for applications where the material is heahsensitive and very Viscous and undergoes a change of state during heating and/or cooling. Examples may be found in starch cooking and cooling, gelatin cooling, freezing of concentrates, and chilling and plasticizing of fats and oils. SPECIAL HEAT TRANSFER PROBLEMS OF THE FOOD INDUSTRY I.P.-dD.D,Lh-
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The work was directed toward finding an industrially usable product from the substanti amounts of acid pickling wastes in the copper and brass industry. This material is at present discarded with no recovery of strategic metals contained therein and frequently constitutes a major disposal problem for compnies lacking disposal facilities. INDUSTRIAL A N D ENGINEERING CHEMISTRY
Vol. 44, No. 3
A spongelike copper of high purity, porous structure, and extremely large surface area w88 prepared from waste pickling sludge from the brass and copper products industry. The material shows evidence of possessing extremely large surface and high chemical activity. Photomicrographe demonstrate that such material can be produced hy very controlled and exacting conditions of preparation. In view of presentday shortages of strategic materials, including copper and zinc, it appeam imperative that experimental work constantly be undertaken to determine methods of economically utiizihg waste materials for new rmrrent work has been provided by the many developments in the use of metall area and high chemical activity for catalytic purposes.
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HIGH PURITY SPONGELIKE COPPER FROM WASTE PICKLING SLUDGE Iw R U L . . d W. l i u l . .
Dryjns #chd&
There are few data in the literature on the effect of air velocity and thickne drying schedules. This work takes into account the resistance offered by the air tilm a t the surface of the specimen bei dried. Due consideration must also he given to the change in the ditrusivity and the temperature of t slab, the dective area available for ditrusion and heat transfer, and how these factors deet the drying schedules. An attempt is made to separate the effectof these resistancesdue to the air lilm fmm tbat of the solid itself. The results make it p i h l e to predict the effect.ofvelocity by drying several thickneises or the effectof thickness by drying at a few velocities.
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RELATIVE MAGNITUDES OF SURFACE AND INTERNAL RESISTANCE IN DRYING rWph E. R u U T. M I H U , d K. W r u a i . Ilu
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w l a in the vmegu WIIIufactIIIhgRoccr This study WBB instituted because of the increasing importance of induetrial water supply in vinegar production. Many papers have been published on the fermentation and brewing industries, but practically no work has bean done on the quality of the dilution water for vinegar manufacture. Water quality is important, because it constitutes the major proportion of the alcoholic solution which is fed to vinegar genera-
tom. All the waters showed variations from the contml water and some ssmples were significantly lower. As high as 8% lowering in performance was noted. In general, the better waters have low solids, hardness, and chloride content. Treated waters--those that have undergone chemical precipitation, aeration, and chlorination-were, in all c a w , better than plant well waters. Other waters may or may not be good, probably depending upon the ratio of the mineral contents rather than on their absolute amounts. Viigar producers have paid little attention to the quality of dilution water employed in plant operations. In early times river, pond, well, and spring waters were used. Increased population with the incidental pollution problems forced the use of wells rather than surface waters. Changes in the level of the water table have in some instancea dected the water in unpredictable ways and the importance of the use of h a t e d waters m o t be stressed too highly at the present time. OPERATION OF PILOT PLANT VINEGAR GENERATORS. EFFECT OF VARIOUS TYPES OF DILUTION WATER I w . ) c L I . ~ , ~ T . W ( . t u f . d h u L Y . ~ & c(b
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Pilot Plant Data Ir synthetic tor oxidem
Inconsistencies in the properties of natural iron oxide pigments and decreasing available supplies iodicated the need for continuing m a r c h on better methods of producing synthetic iron oxides. The work reported here was primarily concerned with utilization of waste pickle liquor, but it has a h been possible to w a variety of iron salt solutionsand other materials as raw materials. Two pilot plants for the production of red, brown, hlack,and yellow oxides, suitable for pigment use,have rn operated at capacities up to 400 pounds per day. The iron salts are pmipitated, oxidized in a conrolled manner, and converted to the desired iron oxide product. The pilot plants are controlled a u t a naticdy and operate continuously and reliably with little manual attention. Continuous operation has been shown to pawas ehst and operating advantages over batch processes. Deaign studies of an ston commercial plant based on the pilot plant work indicate the processes to be economically feasible for use of the varioua pickle liquor wastes produced in iron or steel processing. PIGMENT GRADE IRON OXIDES C. C. hWitR, Y. D., d I amd R- Q.
March 1952
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
ma 449
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