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STAFF-INDUSTRY COLLABORATIVE REPORT Continuous Solids Feed
Separation of Sterols by Countercurrent Crystallization
The problem of delivering solids from a common feed source con tinuously and uniformly to a series of parallel fluidized beds is solved through the movement by dense phase flow of the solids through multiple tubes. The driving force for such movement may be supplied by the pres sure drop of a carrier gas through the solid. The rate is controlled by changing either the size of the outlet orifice of the transfer tube or the carrier gas flow rate. Empirical design equations for moving ground oil shale are presented.
Upjohn uses a 10-stage, semicontinuous, solid-liquid countercurrent extraction process to extract stigmasterol selectively from materials containing mixed sterols having nearly identical physical properties. The process gives over 85% yield of 97% or higher purity stigmasterol. The process also permits recovery of sitosterol. Previous process for separating these sterols was chemical, involved use of expensive, cor rosive chemicals, and gave relatively low yields. Upjohn uses the stigmasterol as the preferred steroidal starting ma terial for synthesis of progesterone, from which a variety of commer cially valuable steroids can be produced. Upjohn is a substantial factor in the $200 million plus steroids busi ness.
DAVID S. KOONS and B. E. LAUER University of Colorado, Boulder, Colo. Ind. Eng. Chem. S3, 970-4 (1961)
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ARTHUR POULOS, J. W. GREINER, and G. A. FEVIG Ind. Eng. Chera. 53, 949-62 (1961)
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Automatic Control of Distillation Columns Recent studies of distillation columns show that many operational problems exist because of improper regulation of the system heat inputs. Both theoretical studies and tests on operating columns show that better regulation and control of the reflux heat, the feed heat, and the reboiler heat can result in more improvements than a cursory inspection indicates. Satisfactory control of the heat inputs has long been difficult because means for proper measurements have not been available. The in ternal reflux computer, the feed enthalpy computer, and rearrange ment of reboiler control hardware have been developed to overcome these difficulties. These control systems provide an economically feasible means for achieving improvement in column operation.
Failure of Thick-Walled Pressure Vessel Because of the increased pressures and temperatures to which pressure vessels are being subjected at present and the still further increases contemplated in the near future, it is necessary to under stand the behavior of materials. In this way, better design methods may be established. For this purpose, failures of pressure vessels were examined, particularly those cases where the failures occurred under controlled conditions. One such case is discussed here. EDWARD^SAIBEL Department of Mechanics, Rensselaer Polytechnic Institute, Troy, Ν. Υ. Ind. Eng. Chem. 53, 975-8 (1961)
D. E. LUPFER and M. W. OGLESBY Phillips Petroleum Co., B-8, Phillips Research Center, Bartlesville, Okla. Ind. Eng. Chem. 53, 963-9 (1961)
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Sulfuric Acid—Optimized Conditions in Contact Manufacture
Coal-tar naphthalene in crude form may be readily upgraded, tar acids and tar bases removed, and the sulfur content reduced markedly by proper choice of variables in hydrorefining with cobalt molybdate on alumina. It was found that 220 volumes of crude naphthalene could be hydrorefined at a temperature of 490° C, a pressure of 175 p.s i.g., a contact time of 5 seconds, and a hydrogen-to-feed mole ratio of 5-to-l, without any loss in efficiency in tar acid, tar base, and sulfur removal. A typical product after distillation contained 14-p.p.m. sulfur, 0.06-wt. % tar bases, and no detectable tar acids, and had a crystalliz ing point of 79.2° C. GERALD GILBERT, RICHARD C. WEIL, and RICHARD H. HUNTER Applied Research Laboratory, U. S. Steel Corp., Monroeville, Pa.
ARTHUR C. HOMME and DONALD F. OTHMER Polytechnic Institute of Brooklyn, Brooklyn 1, Ν. Υ. I/EC
Ind. Eng. Chem. 53, 993-6 (1961)
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Chlorinatioh of Monazite
A catalytic vapor-phase procedure is described for the synthesis of cyanogen, a reactive chemical intermediate, by the oxidation of hydro gen cyanide with nitrogen dioxide. Among the effective catalysts are lime glass beads and compounds of sodium, magnesium, calcium, and silver on supports of low surface area. The selectivity for cyanogen approached 100% and the nitrogen dioxide was completely consumed in runs with a magnesium-containing catalyst at 200° to 350° C. at atmospheric pressure with hydrogen cyanide in excess. The reaction can be the basis of an economical, continuous process for producing cyanogen because the by-product nitric oxide can readily be oxidized to nitrogen dioxide and recycled.
A laboratory scale chlorination of Egyptian monazite sand, 89% purity, was carried out at 900° C. in a horizontal tube furnace. Ninety eight per cent of the thorium content of monazite was attacked and condensed as thorium chloride (99.2% purity) at the temperature range from 850° to 475° C. The purity of thorium chloride was more or less unaffected by the purity of monazite concentrate used, while that of the lanthanons decreased with decreasing the purity of monazite as the chlorides of calcium and magnesium remained admixed with the lanthanon chlo rides. 0 . M. HILAL and F. A. EL GOHARY National Research Centre, Dokki, Cairo
WILLIAM L. FIERCE and WALTER J . SANDNER The Research Center, The Pure Oil Co., Crystal Lake, III. I/EC
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A New Method for the Synthesis of Cyanogen
Ind. Eng. Chem. 53,985-7 (1961)
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Hydrorefining Coal-Tar Naphthalene
Consideration has been given to the general problem of determining how a chemical plant should be run for optimum performance. The most profitable operation can be achieved through a computer plantsimulation program designed to reflect shifting uncontrollable variables. A mathematical model of a contact H2S04 plant was constructed. Ver satility of the model was assured by the development of a method for correlating performance of one catalyst with reference to others. Limitations of the "steepest ascent" method were encountered when attempting to reach the point of best operation. Alternate methods of exploring the response surface were employed to keep within practical limits set by the assumed equipment. Simple "control equations," suitable for use in closed loop plant computer-controllers, were derived to relate the controllable and uncontrollable variables.
Ind. Eng. Chem. S3, 979-84 (1961)
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Ind. Eng. Chem. 53, 997-8 (1961)
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Recovery of Uranium from Calcium Nitrate by Continuous Ion Exchange A study was made of the recovery of uranium from nitrate salt solu tions by continuous countercurrent anion exchange. The nitrate system is the most commonly used nuclear chemical processing system, and standard stainless steel equipment can be used for it. Production rate was found to be only about one eighth as fast in the nitrate system as in the chloride, even after giving the nitrate system the benefit of higher temperature operation. A 99% yield for uranium was indicated for a 10-foot-long bed of 20 to 50 mesh anion exchange resin at 60° C. with a feed rate of 250 gallons per hour per square foot of 6.25N Ca(NO3)2-0.5N HN03. The advantages and disadvantages of the nitrate and chloride systems should be compared for each applica tion to make a choice.
Rigorous Application of Absorption Transfer Unit A rigorous calculation method has been developed for applying the absorption transfer unit to double-phase resistance problems. The rigorous method and other methods are compared in a number of situations. Single-phase resistance cases are included. STANFORD W. BRIGGS School of Chemical Engineering, Purdue University, Lafayette, Ind. Ind Eng. Chem. 53, 988-90 (1961)
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IRWIN R. HIGGINS Chemical Separations Corp., P. O. Box 1031, Oak Ridge, Tenn. Ind. Eng. Chem. 53, 999-1002 (1961)
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Activating Uranium Dioxide Low reactivity U0 2 can be readily converted to a very reactive form by successive oxidation to U3Os and reduction again to U0 2 . The mechanism of activation by this method was studied on aggregates of microcrystalline U02. Physical changes resulting from activation were correlated with changes in reactivity toward HF gas and oxygen. Surface area, pore size, and x-ray measurements showed that activa tion resulted from separation, but not reduction in size, of primary crystallites. Hydrofluorination of U02 to UF4 was found to be sensitive to changes in porosity of the U0 2 during the course of the reaction. Repeated successive oxidation and reduction of the U02 produced first an increase in surface area at constant crystallite size, because of separation of adhering microcrystals, and then a decrease in loose bulk density with both crystallite size and surface area constant, because of further separation of the detached microcrystals.
Unit Processes Reviews Halogenalion L. R. Belohlav and Ε. Τ. McBee
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Combustion Raymond Friedman and J. H. Grover
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R. J. BARD, J. P. BERTINO. and D. L. BUNKER Los Alamos Scientific Laboratory, University of California, Los Alamos, Ν. Μ. Ind. Eng. Cliem 53, 1003-6 ( I 9 6 0
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Chemical Engineering Fundamentals Review Heat Transfer
Crystallization of the Rare-Gas Clathrates
J. K. Ferrell and T. M. G o d b o l d
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Experimental studies were made of variables affecting concentration of the rare gases in clathrate compounds. Twenty two organic com pounds were screened as possible matrix materials, but only /3-quinol and p-fluorophenol were found to trap substantial quantities of gas. Solute concentration, type of solvent, and gas pressure were also varied. Concentrations of argon, krypton, and xenon in crystals of (3-quinol ranged up to the stoichiometric proportion of 1 molecule of rare gas for 3 molecules of solid matrix material. In addition to formation by crystallization from solution, clathrates containing high gas concentra tions can be crystallized by solventless methods. J. E. MOCK, J. E. MYERS, and E. A. TRABANT Department of Nuclear Engineering, Purdue University, Lafayette, Ind. Ind. Eng. Chem. 53, 1007-10 (1961)
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AUTHOR INDEX, SUBJECT INDEX Poisoning in Fixed Beds of Catalysts The effect of distribution of poison in a fixed bed of catalyst on activity has not been considered in detail previously. Thus the average relative activity was evaluated as a function of average poison concentration for combinations of four equations relating activity to poison concentration in an increment of the bed and three equations describing the distribution of poison with respect to bed length for two limiting conditions: (y) The distribution remains the same and the concentration is increased by a constant factor along the bed; and (z) the concentration at the inlet of the bed remains constant, and average concentration is increased by changing the parameter of the dis tribution equation. For condition (z), which most closely approximates poisoning by impurities in the feed, accumulation of the poison near the inlet of the bed usually decreases the effectiveness of the poison.
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R. B. ANDERSON and A. M. WHITEHOUSE Pittsburgh Coal Research Center, Bureau of Mines, Pittsburgh, Pa. nd. Eng. Cliem. 53, 1011-14 (1961)
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