Summary of papers published in this month's research quarterly, I&EC Process Design and Development
FIXED-BED, LIQUID-PHASE DRYING WITH MOLECULAR SIEVE ADSORBENT
EVALUATION OF TEMPERATURE PULSE CHARACTERISTICS AND PULSE TESTING FOR THERMAL DYNAMIC ANALYSIS
The drying of benzyl alcohol by fixed beds of 5A Molecular Sieve adsorbent was studied experimentally. Breakthrough curves were obtained for various bed heights, feed rates, and feed concentrations. The results were well correlated in terms of the mass transfer zone (MTZ) model and suggest that an internal solidphase mechanism controls the adsorption rate.
Experimental temperature pulses were generated and studied in terms of normalized frequency content to evaluate optimum pulse characteristics for the determination of reliable frequency response data. All results indicate that total pulse duration is the best criterion for predicting pulse quality with respect to valid data reduction capability. A wetted-wall column was forced using temperature pulses. The pulse testing data were compared with previously determined direct frequency forced results and mathematical model solutions for laminar and turbulent air flow conditions. The results illustrate the validity of pulse testing but also demonstrate some difficulties and limitations of temperature pulsing for thermal dynamic data recovery.
H . M . Gehrhardt and B . G. Kyle, Kansas State University, Manhattan, Kan. IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 6,265-267 (1967)
C.I. Lewis, Jr., D . F . Bruley, and D . H . Hunt, Clemson University, Clemson, S. C . EFFECT OF A DISSOLVED SOLID ON WIPED-FILM EVAPORATION
Evaporation from saline water films wiped on the outside of a heated vertical copper tube by flexible blades was studied with variable salinity, temperature difference, and wiper speed. An analysis accounting for boiling point elevation due to salinity shows that evaporation rate decreases with increasing salinity and decreasing blade efficiency, a measure of mixing between feed and brine liquids in the blade bow wave. A scraper-wiper combination is desirable. Free surface evaporation was observed with nonboiling feed. Film continuity was poor for pure water, but high for saline water, because of the effects of temperature and salinity on surface tension gradients. Film thicknesses were measured and used in the analysis. Observed evaporation rates were correlated with the analysis by assignments of blade efficiencies which were unity at low wiper speeds and decreased as wiper speed and evaporation rate increased.
Walter Unterberg and D . K . Edwards, University of California, Los Angeles, Calif.
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 6, 268-276 (1967)
IND.END.CHEM.PROCESS DESIGN DEVELOP. 6,281-86 (1967) REACTION KINETICS OF CYCLOHEXANOL-ACETIC ACID ESTERIFICATION
Equimolar cyclohexanol and acetic acid, catalyzed by sulfuric acid with dioxane as the diluent, were esterified in a stirred batch reactor. The reverse reaction, cyclohexyl acetate and water forming cyclohexanol and acetic acid, was also studied. An empirical equation relating the rate constant to initial reactant concentration, catalyst concentration, and temperature was developed. Range of these variables was 1.25 to 5.00M, 0.0930 to 0.1245M, and 104OF. (40' C.) to 176OF. (80' C.), respectively. Experimental forward and reverse reaction rate constants are tabulated for 29 combinations of variables. Nine duplicate esterification runs had a mean deviation of 0.9%. Equilibrium constants are presented for 28 forward runs and seven reverse runs. The empirical equation which was developed predicted rate constants within a n accuracy of about 470 in the range studied.
D. J . McCracken and P. F . Dickson, Colorado School of Mines, Golden, Colo.
IND.END.CHEM.PROCESS DESIGN DEVELOP. 6,286-293 (1967) OXIDATION OF NUCLEAR-GRADE GRAPHITE BY NITRIC ACID AND OXYGEN
The reaction of nuclear-grade graphite with oxygen and nitric acid solution was studied at 275 to 300 O C. and 1000 to 1800 p.s.i.g. Oxygen was bubbled continuously through a reaction vessel containing nitric acid and graphite. Carbon dioxide and nitrogen were the only combustion products. Approximately 1 mole of nitric acid disappeared for every 30 moles of carbon consumed. Reaction rates were approximately proportional to acid normality up to 4.ON nitric acid concentration. With 2.ON acid a t 1600 p.s.i.g. and 300' C., a rate constant of 0.23 hr.-1 was achieved. Air could be used instead of oxygen without excessive sacrifice in rate. Corrosion in the type 347 stainless steel reactor was excessive for 4N acid. Runs made in a rocking autoclave gave much higher rates than the fixed-bed runs, because of either increased decrepitation of the graphite or improved contact between the graphite and the surrounding liquid.
Joseph B. Farrell and Paul A . Haas, Oak Ridge National Laboratory, Oak Ridge, Tenn.
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 6,277-281 (1967)
MOMENTUM TRANSFER STUDIES I N EJECTORS. CORRELATIONS FOR SINGLE-PHASE AND TWO-PHASE SYSTEMS
The performance of a n ejector in single-phase (air-air) and twophase (air-liquid) systems has been studied with air as the motive fluid, and air and various liquids as the entrained fluid. Data for air-air system have been analyzed, using energy and momentum equations; the values of mass entrained calculated from the theoretical expression agreed with experimental results only i n the limited range of small area ratios. Correlations based on the method of dimensional analysis have been developed for both air-air and air-liquid systems relating the mass ratio of entrained fluid to motive fluid in terms of Reynolds number of motive fluid, geometry of the ejector, and the physical properties of the fluid system.
G. S. Davies, A . K . Mitra, and A . N . Roy, Indian Institute of Technology, Kharageur, India IND.END.CHEM.PROCESS DESIGN DEVELOP. 6,293-299 (1967)
(Continued on page 72) VOL. 5 9
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BRIEFS
MOMENTUM TRANSFER STUDIES IN EJECTORS. CORRELATION FOR THREE-PHASE (AIR-LIQUID-SOLID) SYSTEM
PHOSPHATE GLASS PROCESS FOR DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES
Momentum transfer studies i n a n ejector with air as the motive fluid and slurries composed of finely divided solid particles in liquids as the entrained fluid are described. A correlation in terms of dimensionless groups relates the mass ratio of entrained slurry to motive fluid with the Reynolds number of motive fluid, geometry of the ejector, and physical properties of a solid-fluid system.
The conversion of high-level liquid waste to phosphate glass offers a promising means of incorporating fission products in a stable medium suitable for long-term storage. Selection of the phosphate system was based on the simplicity associated with handling the main process stream as a liquid and on the highly unleachable character of the glass product. In the Brookhaven National Laboratory process, a feed solution, prepared by the addition of orthophosphoric acid to raw waste, is reduced in volume by the evaporation of water and nitric acid; then upon heating to 1200 C. in a pIatinum crucible, the remaining volatile material is driven off and the concentrate is converted to molten glass. A pilot plant designed to demonstrate the phosphate glass process on a continuous basis has been operated at BNL for more than two years and has processed simulated reactor waste which would have originated from 57 tons on uranium in reprocessed fuel. The information obtained formed the basis for design of a full-scale demonstration prototype plant now being constructed at Batdelle Northwest Laboratory and scheduled for operation with radioactive fuel wastes in 1967.
G.S. Davies, A . K . Mitra, and A . N . Roy, Indian Institute of Technology, Kharagpur, India IND.ENQ.CHEM.PROCESS DESIGN DEVELOP. 6,299 -302 (1967)
FLOW METHOD STUDY OF THE GAMMA-RAY-INDUCED POLYMERIZATION OF ETHYLENE. INFLUENCE OF FLOW RATE O N POLYMERIZATION
The y-ray-induced gas-phase polymerization of ethylene in a flow system was carried out in a 1-liter continuous stirred tank reactor surrounded by a source of 54,000 curies of cobalt-60 for gamma-irradiation. The polymerization was studied quantitatively by measuring the reaction rate and the molecular weight of the polymer at a temperature of 30" C . , a pressure of 400 kg. per sq. cm. gage, a dose rate of 3.8 X lo6 rad per hour, and various flow rates. O n increasing the flow rate from 300 to 3000 normal liters per hour, the reaction rate decreased from 0.51 to 0.31 C ~ H I mole per liter of reactor volume per hour, and the molecular weight decreased from 9.1 to 5.8 X l o 4 grams per gram-mole. The experimental results indicate that a reaction in a flow system can be kinetically treated by the use of rate constants obtained in a batch system, and that the residence tinie of a polymer in the reactor is not equal to the value of reactor volume divided by the volumetric gas flow rate. This ratio increased from 0.52 to 2.46 with increase in flow rate.
Waichiro Kawakami, Yoshihiko Hosaki, Miyuki Hagiwara, Sueo Machi, and Tsutomu Kagiya, Japan Atomic Energy Research Institute, Takasaki Radiation Chemistry Research Establishment, Takasaki, Gumma, Ja$an
IND.ENO.CHEM.PROCESSDESIGNDEVELOP. 6, 302-308 (1967)
REDUCTION OF FRICTION IN OIL PIPELINES BY POLYMER ADDITIVES
The capacity of oil pipelines may be increased by minute quantities of soluble polymers. T h e effect of the addition of polyisobutylene to crude oil and kerosene has been explored in a n experimental circulation system. I n turbulent flow the friction coefficient is markedly reduced. A critical Reynolds number, Ree, exists, the value of which decreases for smaller pipe diameters, higher molecular weights, and more viscous solvents. Chain elasticity is represented by a calculated relaxation time. T h e onset of drag reduction is characterized by a critical wall shear rate whose reciprocal should be approximately equal to the chain relaxation time. By using this criterion, some relationships were proved. The calculated values of relaxation times were found to be too large. The differences are due to the effects of shear and degradation, as well as the choice of a proper mean molecular weight. The polymers exhibited critical velocities at the range of 8.5 to 14.2 feet per second. Degradation of the long flexible polymeric chain i n turbulent flow remains the bottleneck of drag reduction.
E. J . Tuthill, G. G. Weth, L. C. Emma, G . Strickland, and L. P. Hatch, Brookhaven National Laboratory, {Ifiton, N.Y. IND.ENG.CHEM.PROCESS DESIGN DEVELOP.6 , 314-321 (1967)
SEPARATION OF HYDROCARBONS IN FIXED BEDS OF MOLECULAR SIEVES
The liquid-phase adsorption of n-hexane from cyclohexane, benzene, and 2,2,4-trimethylpentane was studied in a fixed bed of Type 5A molecular sieves at atmospheric pressure from a 5 to 20% n-hexane feed at flow rates between 4 and 60 feet per hour. The effect of flow rate, adsorbent particle size, temperature, feed concentration, and solvent system on the height of the adsorption zone and over-all mass-transfer coefficient is reported. T o a lesser extent, vapor-phase adsorption was studied for the same systems. The effect of velocity on the liquid-phase mass-transfer coefficient is believed to be influenced by convection currents induced by density gradients in the column.
W. J . Schumacher and Robert York, Cornell University, Ithaca, N . Y .
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 6 , 321-327 (1967)
OLEFIN CHLORINATION I N HOMOGENEOUS AQUEOUS COPPER CHLORIDE SOLUTIONS
The application of liquid-phase homogeneous catalysis to the oxyhydrochlorination of ethylene is characterized by virtually perfect selectivity. This is attributed to the ease with which a uniform temperature is maintained and to the mild reaction conditions necessary to achieve economic space time yield.
Arie Ram, Ehud Finkelstein, and Chaim Elata, Technion-Israel Institute of Technology, Haifa, Israel
M . L . Spector, Heinz Heinemann, and K . I). Miller, M . W . Kellogg Co., Piscataway, N . J .
IND.ENG.CHEM.PROCESS DESIGNDEVELOP. 6,309-313 (1967)
IND.ENG.CHEM.PROCESS DESIGN DEVELOP.6, 327-331 (1967)
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INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
BRIEFS PERFORMANCE CHARACTERISTICS OF SELF-ENTRAINMENT EJECTORS
The one-dimensional analysis of ejector performance is extended to include the conditions expected to prevail for a self-entrainment ejector operating a refrigeration cycle. Performance data were obtained for two ejectors operating with two fluids, butane and hexane. Experimental curves are presented for the entrainment ratio as a function of motive and suction fluid pressures and are compared with the performance predicted from the one-dimensional analysis. Compression ratio efficiencies in the range of 56 to 7470 were obtained.
Fouad Khoury, Michael Heymann, and William Resnick, Israel Institute of Technology, Haifa, Israel
IND.ENG.CHEM.PROCESS DESIGNDEVELOP.6, 331-340 (1967)
BATCH MIXING OF VISCOUS LIQUIDS
Mixing times with six-bladed turbines, a marine propeller, and a helical ribbon blender are compared for the agitation of viscous Newtonian liquids. A correlation is developed between a dimensionless mixing number and the Reynolds number. Mixing times are shorter with the turbine than for a propeller of the same diameter at a given Reynolds number. Wall baffles further reduce mixing times. With turbines and propellers, unmixed tori are formed and the time for diffusion into them determines the mixing time. With a helical blender, no unmixed zones are formed and in viscous systems efficiencies based on the power required for mixing are much greater for the helix than for conventional agitators. A plot of power number us. Reynolds number is presented.
R. 7 '. Johnson, Chemstrand Research Center, Inc., Durham, N . C . IND.END.CHEM.PROCESS DESIGN DEVELOP. 6,340-345 (1967)
GRAPHICAL ESTIMATION OF NUCLEATE BOILING HEAT TRANSFER
A method for graphically presenting fully developed nucleate boiling heat transfer correlations currently being used for design purposes enables the engineer to compute a numerical value of the boiling heat flux, or corresponding wall superheat, rapidly and without knowledge of the physical properties of the fluid, other than at one arbitrary reference state.
Walter Frost and G . S. Dzakowic, University of Tennessee Space Institute, Tullahoma, Tenn.
further handling of the plutonium product in a n unshielded facility. Problems with incomplete dissolution and feed adjustment were successfully overcome.
J . S. Eargle, C . W. Swindell, and R. I. Martens, E. I . du Pont de Nemours &? Go., Inc., Aiken, S. C. IND.
ENG. CHEW PROCESS DESIGN DEVELOP. 6, 348-353 (1967)
PARTIAL COMBUSTION OF FUEL OIL WITH OXYGEN AND APPLICATION TO SMELTING IRON ORE
The partial combustion of heavy residual fuel oil with oxygen was studied in a n atmospheric test chamber and in a shaft reactor using a scaled-down model of a commercial air-atomizing vortex burner. I n the teat chamber, a t least 15% more oxygen than theoretically required for partial combustion was needed to achieve 80% gasification of carbon. I n the reactor, which provided longer residence times and lower heat losses, the gasification was generally better than 95% with at least 1501, excess oxygen. T h e shaft reactor and partial combustion system were successfully operated as a n iron-ore smelter with a burden of self-fluxing sinter and coke. The solid carbon ratio was 300 pounds per ton of hot metal, and the total carbon ratio was 1300 pounds per ton of hot metal. Burden movement and permeability, which were expected to be problems, were good even a t the lowest coke ratio.
Jerome Feinman and D . A . Kuskat, Monroeville, Pa.
U.S. Steel Corp.,
IND.ENG.CHEM.PROCESS DESIGNDEVELOP.6, 354-363 (1967)
DYNAMICS OF A CONTINUOUS STIRRED-TANK POLYMERIZATION REACTOR
The dynamic response of a continuous stirred-tank polymerization reaction has been investigated in terms of process variables and monomer and initiator properties, with particular emphasis on the number-average molecular weight of the product. The transient responses and offsets resulting from step changes in inputs to the reactor were calculated on a digital computer for variour initial steady-state conditions. For the free-radical addition reactions of monomers in the concentration range of 10 to 2070, the results indicated that molecular weight can be most easily controlled by regulating the feed temperature without worrying about removing heat from the viscous reaction mass.
T . A . Kenat, R . I. Kermode, and S. L . Rosen, Carnegie Imtitute of Technology, Pittsburgh, Pa.
IND.ENG.CHEM.PROCESS DESIGNDEVELOP. 6, 363-370 (1967)
IND.END.CHEM.PROCESS DESIGNDEVELOP. 6, 346-347 (1967) STABILITY OF CALCIUM SULFATE HYDRATES IN WET-PROCESS PHOSPHORIC ACID
LARGE SCALE PROCESSING OF HIGHLY IRRADIATED PLUTONIUM BY SOLVENT EXTRACTION AND ION EXCHANGE
Irradiated target assemblies were dissolved in nitric acid, and the resultant feed was clarified by centrifugation to remove undissolved solids. Plutonium was separated from aluminum, fission products, and transplutonium elements either by two cycles of continuous solvent extraction or by two to four stages of anion exchange. Recovered plutonium was concentrated by ion exchange, precipitated, and calcined to the oxide. I n two of five programs, americium and curium were also recovered in a nitrate solution after partial separation from fission products by precipitatian as sulfates or batch solvent extraction. Performance of both solvent extraction and ion exchange during five programs was excellent, with 96% or more of the plutonium recovered from the feed. Fission product radioactivity was reduced to a level that permitted
The temperature of the transition between calcium sulfate dihydrate and hemihydrate in mixtures of phosphoric acid, sulfuric acid, and water depends upon the activity of water, and is thus a function of water vapor pressure over the solutions. I n wetprocess phosphoric acid the vapor pressure of water is affected by impurities and differs slightly from that i n pure systems of comparable PZOScontent. The transition temperatures observed experimentally in wet process acid, however, are considerably higher than those predicted from measured vapor pressure. Data are presented comparing the predicted transition temperatures in wet-process acid, based on vapor pressure, with those determined experimentally.
R . L . Gilbert, Jr., American Cyanamid Co., Princeton, N . J . IND.ENG.CHEM.PROCESS DESIGNDEVELOP.6, 371-374 (1967) (Continued on page 74) VOL. 5 9
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BRIEFS ELECTRICAL AUGMENTATWN OF NATURAL GAS FLAMES
RESISTANT
An improved version of an electrically augmented burner has been developed in which a powerful, 60-cycle electrical discharge can be maintained in the combustion products from a natural gas-air flame, and maintained in a completely diffuse mode. Proper preconditioning of the gas appears to be the most essential factor tending to oppose contraction of the discharge into an arc filament. A high degree of turbulence, both in the discharge zone and in the approach stream, also assists in combating filament formation, the effect being most noticeable at high electrical power levels. The diffusely augmented flame has potential technical and economic advantages over other sources of high temperature heat that are expected to be significant to chemical, metallurgical, and other industrial uses. Experimental work with respect to various such applications is continuing.
VACUUM FILTER Small
C . W . Marynowski, Stanford Research Institute, Menlo Park, Gal$., B . Karlouitt, Combustion and Explosives Research, Znc., Pittsburgh, Pa., and T . J.Hirt, Northern Natural Gas Co., Menlo Park, CaliJ.
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IND. ENG.CHEM.PROCESS DESIGN DEVELOP. 6, 375-379 (1967)
CATALYTIC AND THERMAL DECOMPOSITION OF ISOPROPYL METHYL FLUOROPHOSPHONATE
Decomposition products of isopropyl methyl fluorophosphonate (Sarin or GB) vapor in air at temperatures between 300" and 400" C. in the absence of catalyst are exclusively propylene and methyl phosphonofluoridic acid, presumably arising from an intramolecular dealkylation reaction. Catalytic decomposition of GB vapor over platinized alumina results initially in stoichiometric amounts of the oxidation products COS, HF, H?O, and HgP04. As the activity for catalytic oxidation declines, the decomposition over the catalyst shifts to dealkylation, as in the absence of catalyst. The steady-state rate of dealkylation is very much greater in the presence of catalyst than either in its absence or in the presence of unplatinized alumina. Catalytic dealkylation has been followed for periods of operation corresponding to the complete conversion of an amount of GB equal to four times the weight of catalyst, with no evidence of deactivation.
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R. W . Baier, Philco-Ford Corp., i\Tewport Beach, Gal?., and S. W . Weller, State University of New York at Buffalo, Buffalo, N . Y . IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 6, 380-385 (1967)
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ENHANCEMENT OF FORCED CONVECTION HEAT TRANSFER COEFFICIENT USING DETACHED TURBULENCE PROMOTERS
The effect of square cross-section rings supported away from the heat transfer surface (detached turbulence promoters) on the rate of forced convection from condensing steam to water was studied in a vertical tube geometry. Uniformly spaced detached promoters produced significant increases in heat transfer coefficients, but the pressure drop was relatively large. By combining rings in pairs with considerable separation between pairs it was possible to increase the over-all heat transfer coefficient with significantly smaller increase in pumping power than would have been required by simply increasing the velocity.
David G . Thomas, Oak Ridge National Laboratory, Oak Ridge, Tenn.
For complete information write for 4-page reference manual CATALOG 25.
SPRAYING SYSTEMS GO. 3255 Randolph.Street Bellwood, Illinois 60104
IND.END.CHEM.PROCESS DESIGN DEVELOP. 6, 385-390 (1967)
COMMUNICATION. MECHANISM OF PELLET GROWTH I N WET PELLETIZATION ?
Recent investigations have shown that during the batch wet pelletization process the pellet size distribution is self-preserving. Different models for the process have been proposed to account for this behavior. Tracer experiments on the wet pelletization of sand aid in understanding the mechanism of pellet growth.
C. E. Capes, n'ational Research Council, Ottawa 2, Canada IND.END.CHEM.PROCESS DESIGNDEVELOP. 6, 390-392 (1967) Circle No. 19
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