BRIEFS Summary of papers published in this month’s research quarterly, I B E C Process Design and Development Subscription rates for this and associated quarterlies:
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EFFECT OF WALL FRICTION I N COMPRESSIONPERMEABILITY TESTING
HEAT TRANSFER I N A CONTINUOUS VIBRATION-PROMOTED TURBULENT FILM
Experimental work was undertaken to measure the effect of wall friction in compression-permeability testing, to account for a t least part of the difficulties in correlating data from compressionpermeability cells with those from constant pressure filtrations. Two compression-permeability test cells differing only in diameter were constructed, and statistically controlled experiments were made with each cell, using varying cake thicknesses and constant solids pressure. Variance analysis showed that specific resistance decreased as cake thickness increased. For cakes of the same thickness in the two cells, the specific resistance was greater for the test cell of the larger diameter. These results are those expected if friction exists between the cake and the wall of test cells.
Water flows through a tube subjected to a rotary space vibration, as a thin rotating turbulent film. Its heat exchange characteristics were studied a t frequencies between 800 and 1600 r.p.m,, amplitudes between 6.5 and 8.9 mm, viscosities between 0.5 and 32.5 cp: thermal conductivities between 0.218 and 0.540 cal. hr.-I min.-l.C.-l, surface tensions between 43 and 73 dynes per cm., and residence times between 4.8 and 9.9 seconds. Film thickness is a function of axial and vibrational Reynolds numbers. A design correlation adequate for this type of heat exchangers is Nu - 1.175 Re,O 5zPro.43. The smaller error corresponds to acorrelation with fluid properties at bulk temperature, compared with “film” temperature or the viscosity correction factor ~ * / p * . T h e axial Reynolds number has no significant influence on the Nusselt number. Heat augmentation is discussed, with several criteria. Heat transfer is controlled by the liquid thermal conductivity rather than by viscosity. A theoretical model based on the pcnetration theory agrees reasonably well with the experimental correlation.
F. L. Rawling, Jr., E. I . du Pont de Nemours Gp1 Go., Inc., Richmond, Va., and D . R. Boylan and H. T . David, Iowa State Universib, Ames, Iowa 50010 IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 161-164 (1970)
Enrique Rotstein, Martin Urbicain, Miguel Elustondo, and Numa J . Cajiati, Universidad Nacional Del Sur, Bahia Blanca, Argentina RATE OF BALL MILLING AND VIBRATION MILLING ON THE BASIS OF THE COMMINUTION LAW PROBABILITYTHEOREM
T h e grinding mechanism of ball mill and vibration mill is expressed in terms of probabilities. Theoretical relations among operational variables derived from the final rate equations are confirmed by empirical facts, suggesting that the over-all treatment of milling mechanism in this paper is satisfactory. T h e relationship between the probabilities in this paper and the selection function or the breakage function in grinding kinetics is briefly discussed.
Kunio Tamura and Tatsuo Tanaka, Hokkaido U n i v e r s i p , Safiporo, Japan IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 165-173 (1970)
MECHANISM OF SEGREGATION AND BLENDING OF PARTICLES FLOWING OUT OF MASS-FLOW HOPPERS
The mechanism of segregation and blending of a binary mixture of particles flowing out of a mass-flow hopper is theoretically analyzed on the basis of the screen or hypothetical-hoppers model, where small particles pass through the interspaces of large particles during flow. As a result, the patterns of segregation and blending are described by material balance within the hopper, depending on variations of the mass flow rate and the mixing ratio with the elapse of discharge time. Satisfactory agreement between the experimental and calculated results verifies this model and the analysis.
Kunio Shinohara, Karunori Shoji, and Tatsuo Tanaka, Hokkazdo University, Sapporo, Japan IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 174-180 (1970) 80
INDUSTRIAL AND ENGINEERING CHEMISTRY
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 180-185 (1970)
EXPERIMENTAL STUDY OF EFFECT OF VIBRATION ON FRICTION FACTOR IN FLOWS THROUGH CURVED PIPES
Friction factor was studied for flow through curved pipes, both stationary and subjected to vibration. Flow conditions were Reynolds numbers ranging from 350 to 2000 for the stationary type and 600 to 1400 for the one under vibration. T h e curved pipes were two sets of copper coils with curvature ratios, inside diameter to helix diameter of 1 to 23.25 and 0.5 to 14.5 inches, respectively. T h e conditions of vibration were frequencies varying from 30 to 125 cps and amplitudes of displacement from 0.001 to 0.020 inch. Two empirical equations for estimation of the friction factor for flow through curved pipes under vibration are presented in terms of Reynolds number, curvature ratio, and dimensionless vibration number. T h e ratio of the friction factor of a curved pipe subjected to vibration to that of the stationary curved pipe was also estimated and is presented in a graphic form. C. G. Vytoyannis and H.- W . Hsu, The University of Tennessee, Knoxville,
Tenn. 37916 IND. ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 186-190 (1970)
EFFECTS OF CERTAIN FACTORS ON THE RADIATION-INDUCED POLYMERIZATIONOF METHYL METHACRYLATE
The effects of hydroquinone, oxygen, and acetone on the radiation-induced polymerization of methyl methacrylate were studied. Irradiations were performed in a medium-intensity gamma radiation chamber created by neutron activation of 55Mn. Resultant
radiation dose rates varied between 1.4 and 3.2 X 106 rads per hour initially and diminished with a 2.58-hour half life. Hydroquinone acted as a n ideal inhibitor, oxygen as a n ideal retarder. Their effects were independent of one another. Solutions of M M A in acetone exhibited the “simple dilution effect.” The effects of hydroquinone and oxygen in MMA-acetone were similar to those in bulk MMA. Conversion of the monomer for a given dose was independent of dose rate for dose rates in the range 1 X 104 to 3.2 X 106 rads per hour.
C. A . Detrick and J . L . Kelly, University of Virginia, Charlottesville, Va: 2290 1
IND. ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 191-194 (1970)
REDUCTION OF IRON ORE WITH HYDROGENIN A DIRECT CURRENT PLASMA JET
A quantitative study was made of the effect of power input, reducing gas concentration, and particle size on reduction of iron ore in a d.c. plasma jet. Ore was injected into the plasma as it emerged from the anode orifice and the reduced product collected in a water-cooled quenching chamber. Reduction increased with greater energy i n the plasma and decreased with increasing ore size. Reduction with hydrogen plasma gas ranged from 33 to 69y0 and with 2570 hydrogen-75% argon plasma gas from 6 to 42%. Computed mean temperatures for the plasma gas discharging from the anode ranged from 4300’ to 10,300’F. X-ray analyses and microscopic examination of the collected product revealed chemical and physical changes as the amount of reduction varied. Heat transfer to the ore is a n important if not the prime factor influencing the reduction process.
H. L. Gilles and C. W. Clump, Lehigh University, Bethlehem, Pa. 18015 IND.ENG.CHEM. PROCESS DESIGN DEVELOP. 9, 194-207 (1970)
EVAPORATION OF WATER IN AIR, HUMID AIR, AND SUPERHEATED STEAM
The rate of evaporation of water into air, humid air, and superheated vapor was estimated. When the mass velocity is constant, a t one inverse point the evaporation rate is the same for different degrees of humidity. U p to this point, it decreases as the humidity increases, above it, this relation is reversed. These relations were confirmed experimentally by a wetted wall column with countercurrent water and air, after which the heat and mass transfer coefficients were calculated. O n the basis of these studies, modern dryers might be modified and extended to a completely closed circuit. Heat and mass transfer obtained were: J H = (hc/c,Gm) PrzIa = 0.029 Re-0.2 and J D = (kDpEMMm/Gm)Scz/a = 0.022 Re-0.2.
Tetsuo Yoshida and Tsutomu Hyodo, Osaka City University, Osaka, Japan IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9,207-214 (1970)
RADIATION-INITIATED SIDE-CHAIN CHLORINATION OF TOLUENE. KINETIC INVESTIGATIONS
The radiation-induced side-chain chlorination of toluene was investigated using accelerated electrons as the radiation source. The reaction was carried out to complete side-chain chlorination within the temperature range of 80’ to 150°C. Contamination by-products resulting from substitution and addition a t the aromatic nucleus were small. The conversion of toluene to bcnzotrichloride follows three consecutive reaction processes and the yield efficiencies are approximately inversely proportional to the square root of the radiation dose intensities. At reasonable dose intensities, the yield efficiencies are sufficiently high to merit considerations for commercial application of a radiation reactor for the production of benzotrichloride.
J . Y. Yang and C. C. Thomas, Jr., Western New York Nuclear Research Center, Inc., Bufalo, N . Y., 14214, and H. T . Cullinan, State University of New York at Buffalo, Buffalo, N . Y. 14214
IND. ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 214-222 (1970)
RADIATION-INITIATED SIDE-CHAIN CHLORINATION OF TOLUENE. CONTINUOUS REACTOR DESIGN
A theoretical investigation of the design of a chemical reactor for the continuous beta-radiation-induced side-chain chlorination of toluene to produce benzotrichloride is described. The reactor configuration considered is a liquid-phase fluidized bed containing active beta source particles maintained in a fluidized condition by the upward reactants feed and recycle flow. A model is developed based on empirical expanded bed characteristics, gross G-value kinetics, empirical radiation energy utilization experience, and an axial-dispersed plug flow equation. Results for energy utilization efficiency, reactor geometry, and source strength requirements are presented. The problem of source attrition is discussed.
H. T. Cullinan and H.Rhambia, State University of New York at Buffalo, Buffalo, N . Y., 14214, and J . Y. Yang and C. C. Thomas, J r . , Western New York Nuclear Research Center, Inc., Buffalo, N . Y . 14214 IND.ENG.CHEM. PROCESS DESIGN DEVELOP. 9, 222-229 (1970)
RECTIFICATION OF METHYLCHLOROSILANES
A highly efficient laboratory column of special design and a procedure for rectification a t atmospheric pressure of moisturesensitive and chemically active liquids are described. The distinguishing features of the column are the application of a special head, the use of a thermistor for the rectification temperature measurement, a simplified method of preparing thin glass spiral package threads (by processing in H F solution), a simplified and effective way of vaporization in the column still, and the avoidance of the ground-glass jamming due to silanes by introducing the tapered Teflon tube. Methylchlorosilanes of 99.5 to 99.8y0 VOL. 6 2
NO. 4
APRIL 1 9 7 0
81
The Pump That Never Gets Wet
BRIEFS purity were isolated, their physicochemical parameters having been determined. Literature data on methylchlorosilanes are few.
Saleh N . Hajiev, Institute of Physics,Academy of Sciences of the Azerbaijan SSR,Baku, USSR IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 229-233 (1970)
DYNAMICS OF PACKED TOWER DISTILLATION
The transient response of the enriching section of a packed distillation column to a step change in the reflux ratio was investigated, The solution in the case of a straight-line equilibrium curve was adapted to the real case (with a nonlinear equilibrium curve). This solution gives the liquid concentration, x, at any height of column, I, after the step change in the reflux ratio, in the form of a series of exponential functions of the time, t: x ( t , m ) - x ( z , t ) = n
Cz(z)e8't, where the s,s'
MAC
are negative constants which depend
i=l
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only on the parameters characteristic of the final steady state, but not on the magnitude of the step disturbance, and the coefficients Ci's depend on z only. A series of exponential terms is a convenient form of the solution for computing transfer functions, which are used in the control theory. Since the experimental d a t a available were insufficient, a laboratory scale column was built and new data were taken. The basic results of the linear solution seem to be valid also for nonlinear systems. The first time constant, SI, is either independent or a slowly varying function of column height. It does not depend on the magnitude of the step disturbance or depend on the value of the initial concentration, but only on the parameters characteristic of the final steady state.
Giulio Tommasi and Philifi Rice, Syracuse University, Syracuse, N . Y .
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 234-243 (1970)
I
EVALUATION OF ACTIVITY COEFFICIENTS FROM TERNARY LIQUID-LIQUID EQUILIBRIA
12054-'/d SWIVEL PNEUMATIC
I n a calculation procedure for evaluating parameters in activity coefficient equations from ternary liquid-liquid equilibrium data, the parameters are obtained via function FSQ, 3
m
i=l
j-1
FSQ =
Swivel ball mounting for positioning tip as desired within 40" spherical range. Permits adjustment of spray direction without disturbing pipe connections Choice of flat a n d round s p r a y set-ups i n wide range of capacities. Swivel Adapter also available for converting present Spraying Systems 1/4 J P n e u matic Atomizing Nozzles. W r i t e for D a t a Sheets 12148, 12149 a n d 12049.
(x,jyij
- x ' 13Y , 'GI2
where x is mole fraction of components in the saturated phases represented by tie line j , and y is the corresponding activity coefficient represented by the chosen equation. Thermodynamic equilibrium requires FSQ = 0, but because of experimental error in the tie line compositions and inability of the chosen equation to represent activity coefficients exactly, the best set of parameters is found by minimizing FSQ. A pattern search technique was used to locate the minimum. The effect of experimental error in tie line compositions upon the calculated parameters was studied and methods of moderating it were incorporated into the procedure. The procedure was tested on several systems and found reliable. D. S. Jv and B. G. Kyle, Kansas State University, Manhattan, Kan. 66502
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9 , 244-247 (1970)
CATALYTIC REDUCTION OF NITROGEN DIOXIDE WITH HYDROGEN
For spray performance data.
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The reduction of nitrogen dioxide with hydrogen over four solid commercial catalysts was studied in a flow reactor operated a t atmospheric pressure and 160' to 27OoC. Reactant partial pressures were varied from 0.007 to 0.1 atm. For the catalysts studied, nitrogen, ammonia, and water were the only important
BRIEFS products. For a barium-promoted copper chromite catalyst, the effects of temDerature. initial reactant concentrations. and space velocity on the N) to NHs ratio in the products were investigated. T h e relative abundance of Nz increased with increasing space velocity. Differential kinetics data were taken with this catalyst and fitted to a rate expression. Rate increased with increasing Hz pressure and was inhibited by NOS.
Richard J . Ayen and A l i Amirnazmi, University of California, Berkeley, Calif.
IND.ENC.CHEM.PROCESS DESIGN DEVELOP.9, 247-254 (1970)
EXPERIMENTALSTUDY OF HEAT TRANSFER TO VISCOELASTIC FLUIDS
T h e heat transfer characteristics of viscoelastic, nonNewtonian fluids flowing through a uniformly heated test section were examined experimentally. The fluids were produced by the addition of small percentages of a high-molecular-weight substance (guar gum) to water. (These solutions had been previously investigated for their drag-reducing capabilities.) Heat transfer and pressure drop data were taken in the turbulent flow region for two different diameter tubes with additive concentrations varying from 50 to 2400 p.p.m. A significant reduction in heat transfer was observed when these high-molecular-weight additives were introduced into a water solvent, far greater than the previously established drag reduction for this class of fluids. An analysis is presented for predicting the heat transfer effect without apriori friction factor data.
J . C. Corman, General Electric Go., Schenectady, N . Y. 12301
IND.ENG.CHEM.PROCESS DESIGNDEVELOP.9, 254-259 (1970)
DISTRIBUTION OF ISOMORPHOUS SALTS BETWEEN AQUEOUS AND SOLID PHASES IN FRACTIONALCRYSTALLIZATION
T h e distribution of isomorphous salts between aqueous and solid phases in fractional crystallization was determined. The results were examined from the stand-point of theoretical equations developed by Doerner and Hoskins, Berthelot and Nernst, and Abu Elamayem. Calculations of the distribution constants, X and D, employed in the Doerner and Hoskins and Berthelot and Nernst equations, respectively, show that these equations are not strictly applicable to the systems studied. Experimental results can be quantitatively explained, however, by Abu Elamayem’s equation. T h e less soluble salt is separated more effectively by allowing a small weight fraction of the crystals to separate from a ternary system.
TRANSIENT HOLDUP BEHAVIOR OF A PULSED SIEVE PLATE SOLVENT EXTRACTION COLUMN
Equations to describe the transient holdup behavior of a pulse column operating in the emulsion region were derived assuming stagewise behavior of the pulse column. Slip velocity is used to eliminate the dispersed phase flow rate from the equations, and previous data show that slip velocity is a function only of pulsing conditions. Experimental data were taken using a fluorescent tracer technique to measure the transient holdup. The computer solution of the equations was in substantial agreement with the data, except that it led the experimental time response slightly: This shift may have been due to the slowness of coalescence of the dispersed phase droplets when the pulse column operating conditions changed. When the model was modified to include a term that accounts for a finite coalescence of the dispersed phase, the calculated results showed better agreement with the experimental data.
H. R. Foster, Jr., R. E. McKee, and A . L. Babb, University of Washington, Seattle, Wash. 9 8 1 0 5
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 272-278 (1970)
MODEL FOR OXIDATIVE THERMAL DECOMPOSITIONOF STARCH IN A FLUIDIZED REACTOR
The oxidative thermal decomposition of starch was studied in a tapered fluidized bed reactor at pressures from 1 to approximately 0.5 atm and at molar oxygen concentrations from 0 to 21W in nitrogen as the fluidizing gas. The decomposition of starch proceeds very rapidly after the “critical” temperature is reached and is accompanied by the liberation of a pulse of heat. With air as the fluidizing medium, the critical temperature was about 24OOC. The concept of starch particles of varying reactivity has been used in analyzing the results. The reaction rate was proportional to the oxygen concentration in the fluidizing gas. Yields of levoglucosan were low.
S. L. Jariwala and H. E. Hoelscher, University of Pittsburgh, Pittsburgh, Pa. 15213 IND.ENG. CHEM.PROCESS DESIGNDEVELOP.9, 278-284 (1970)
KINETICS OF CUPROUS IODIDE OXIDATION WITH AIR
The kinetics of oxidation of cuprous iodide with air was studied in a batch system by the thermogravimetric technique between 300 O and 400 O C . Cuprous iodide precipitated as microparticles was used, and all experiments were carried out using a large excess of oxygen. The reaction was autocatalytic, with an activation enerm of 13.5 kcal/g-mole. Reaction rate data were correlated by the semiempirical equation ( d x l d t ) = 3.53 X IO* exp(-l3,500/RT) xO*es (1 x)o44 by using linear regression. With this equation and the residence time distribution function for series of equal-sized backmix flow vessels, conversion was estimated us. residence time and number of ideal backmix stages under the assumption of completely segregated flow. These results were compared with those for plug flow of solids. “I
A . S. Ananda Murthy and D. S. Mahadevappa, Universiv of Mysore, Mysore 6, India
IND. ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 260-263 (1970)
I
V
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THERMODYNAMICS OF SOLIDSOLUBILITY IN~RYOGENICSOLVENTS
Heinz J . Neuburg, Universidad TLcnica del Estado, Santiago, Chile
A thermodynamic framework is given for estimating the solubilities of solids in cryogenic liquid solvents. The activity coefficient of the solid in solution is referred to the pure subcooled liquid; activity coefficients are calculated from Scatchard’s equation with a correction to Hidebrand’s geometric-mean assumption for cohesive energy density. Alternatively, activity coefficients may be calculated from a cell-theory partition function. The methods discussed are applicable to single and mixed solvents.
IND.
G. T. Preston and J. M . Prausnitz, University of California, Berkeley, Calif,94720
IND. ENG.CHEM.PROCESS DESIGNDEVELOP. 9,264-271 (1970)
ENC.
CHEW
PROCESS DESIGN DEVELOP. 99 285-288 (1970)
BINARY VLE CORRELATION INCLUDING HEAT OF MIXING DATA EXPLICITLY
A method for correlating binary vapor-liquid equilibrium data is based on the combination of thermodynamically derived expressions for as a power series in composition and as an integrated power series in temperature. The correlation is easily adantable to comDuter solutions. I t handles heat of mixins in a natural fashion. Published experimental VLE data were cor-
- .
Q
VOL. 6 2
NO. 4 A P R I L 1 9 7 0
83
BRIEFS related and heat of mixing data calculated. The calculated data agreed well with published experimental values.
tions. Attention is given to predicting helium solubility in mixed solvents.
P. S. Lowell, Radian Corp., 8409 Research Biud., Austin, Tex. 78758
K . A . Solen, P.L. Chueh, and J.M . Prausnitz, HeZium Research Center, Bureau of Mines, Amarillo, Tex., 79106, and University of California, Berkelty, Calif. 94720
and Matthew Van Winkle, University of Texas, Austin, Tex.
IND.ENG.CHEM.PROCESS DESIGNDEVELOP. 9, 289-292 (1970)
IND.END.CHEM.PROCESS DESIGN DEVELOP. 9, 310-317 (1970)
CATALYTIC DEHYDROGENATION OF 2-PROPANOL TO ACETONE
THIN FILM EVAPORATION ENHANCEMENT BY FINNED SURFACES
Catalytic dehydrogenation of 2-propanol over Cu:SiOz catalyst was investigated. The undesired side reaction of dehydration can be controlled by a selective catalyst and choice of paper operating conditions. The kinetics of the heterogeneous catalytic reaction can be adequately expressed by a forward first-order and reverse second-order mechanism. The rate-controlling step with chemically pure 2-propanol is single-site surface reaction, while for the technical grade alcohol, the adsorption of alcohol is rate-controlling. The static bed data are compared with the fluidized bed data.
Evaporative heat-transfer coefficients of thin films of water Aowing down the inside of vertical tubes were markedly increased by clamping longitudinal rectangular fins to the tube surface. At a heat flux of l o 4 Btu/hr.ft2, ten 0.013-inch-wide fins on the inside of a tube 42l/2 inches long and 0.44-inch4.d. gave an evaporative coefficient of 8000 Btu/hr .ft2’F compared with 600 for the same tube without fins, a h / h , ratio of 13.3. The enhancement of the film evaporation coefficient decreases as the feed rate is increased or decreased from the optimum, as the heat flux increases, and as the number of fins decrease.
S. S. Lokras, P. K . Deshpande, and N . R. Kuloor, Indian InJtitute of Science, Bangalore 12, India
D . G. Thomas and Gale Young, Oak Ridge National Laboratory, Oak Ridge, Tenn. 37830
1 % ENG. ~ . CHEM.PROCESS DESIGN DEVELOP. 9, 293-297 (1970)
IND.END.CHEM.PROCESS DESIGN DEVELOP. 9, 317-323 (1970) DYNAMIC RESPONSE TO CONCENTRATION CHANGES OF A PARTLY FILLED HORIZONTAL TANK
COAL AND CHAR TRANSFORMATION IN HYDROGASIFICATION OF COALS RANGING IN RANK FROM LIGNITE TO LOWVOLATILE BITUMINOUS
The effect of rank on the behavior of coal a t different stages i n the hydrogasification process was investigated petrographically. Among five high-volatile bituminous coals tested, the yield of coal from the pretreatment process increased slightly with rank. Structure and anisotropy of the hydrogasification residues indicated that the higher the rank of the coal, the greater the fluidity in the interior of the particles when they were rapidly heated in the reactor. Escape of this material from inside the pretreatment skin caused agglomeration when a low-volatile bituminous coal was processed. Lignite and subbituminous coals, run without pretreatment, gave residue chars with a lenticular pore structure. I n some regions of these residue chars, the presence of rounded pores indicated the development of a degree of plasticity.
Natural mixing in a partly filled horizontal tank due to flow rate and relative position of inlet and outlet was studied on three tanks from 5.7 to 36 inches in diameter. Length diameter ratio was 3 to 1. Three liquid levels were maintained and flow rate was varied. Concentration transfer functions usually included a small dead time or delay before any change i n output occurred. Dead time increased as tank diameter increased. Bypass or shortcircuiting from inlet to outlet without mixing occurred when outlet was directly under inlet. Time constants are related to mean residence time. Relations are recommended for concentration transfer functions for many arrangements of inlet and outlet.
R. M . Hubbard, J . L . Dalferes 111, G. C. Lahn, and W . W . Zalewski, University of Virginia, Charlottesuille, Va. 22901 IND.END.CHEM.PROCESS DESIGN DEVELOP. 9, 323-330 (1970)
D. M . Mason, Institute of Gas Technology, Chicago, Ill. 60616 IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 298-303 (1970)
APPLICATION OF A SUBOPTIMAL DESIGN METHOD TO A DISTRIBUTED-PARAMETERREACTOR PROBLEM
The optimal heat flux profile for a packed tubular reactor with significant radial gradients has been estimated, using a suboptimal hybrid method which employs both lumped- and distributedparameter equations. Improvements in yields compared to the one-dimensional approach are significant, with approximately half the computational effort of the two-dimensional procedure. J . D . Paynter, J . S. Dranoff2 and S. G . Bankoff, Northwestern University, Evanston, Ill. 60201
IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 303-309 (1970)
GAS SEPARATIONS WITH HIGH-FLUX CELLULOSE ACETATE MEMBRANES
Separation of helium from natural gas by permeation through a membrane has been suggested as a competitor to the cryogenic method currently employed. Measurements of permeation rates for helium and other gases indicate that cellulose acetate membranes of the type used for desalination by reverse osmosis may be more suitable for this application than those previously studied. Permeation rates [in units of 10“ cm3(STP)/cm2-sec-cmof Hg] have been obtained for He, 10.6; Ne, 1.0; 0 2 , 0.71; Ar, 0.37, CH4, 0.34, and N2, 0.31 ; all at 22OC. Higher operating temperatures gave a higher ratio of He/N2 flow rates, but no samples gave as good a ratio as that obtained from an “ordinary” membrane of cellulose acetate.
P. K. Gantzel and Ulrich Merten, Gulf General Atomic Inc., San Diego, Calif. 921 12 IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9, 331-332 (1970)
THERMODYNAMICS OF HELIUM SOLUBILITY IN CRYOGENIC SOLVENTS AT HIGH PRESSURES
High-pressure solubility data for helium in cryogenic solvents have been reduced with a modified Redlich-Kwong equation for vapor-phase properties and a modified Krichevsky-Ilinskaya equation for liquid-phase properties. The results provide a useful correlation of helium solubilities for engineering design calcula84
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
LINEAR APPROXIMATION OF NONLINEAR CONSTRAINTS
The quality characteristics which are unknown, nonlinear functions of the composition of a blend can be expressed, for purposes of linear programming, by :
wherey = prescribed characteristics of the blend,yi = characteristics of the components, x i = per cent of component i, and aj; = constants determined from experimental data.
6. J. Auslaender, Institute Petrochim, Ploesti, Romania IND.ENO.CHEM.PROCESS DEVELOP. 9,333-334 (1970)
SCREENING OF PRODUCT INHIBITION EFFECTS BY TRANSIENT RESPONSETECHNIQUES
The shapes of response curves to step perturbation of feed concentration provide a rapid method for screening adsorption behavior in surface reaction. Relative magnitudes of adsorption equilibrium constants and, in some instances, adsorption rate constants, for reaction products can be identified from the measurement of such responses. The method is demonstrated for an example based on published data for the dehydration of ethanol on Dowex-50.
Reiji Mezaki, J . B. Butt, and L. H . Shendalman, Yale University, New Haven, Conn. 06520 IND.END.CHEM.PROCESS DESIGN DEVELOP. 9,334-337 (1970)
SPOUT-FLUID BED TECHNIQUE
The spout-fluid bed is a unique fluid-particle-agitated bed in which spouting and fluidizing occur simultaneously. This technique overcomes such inherent limitations as stratification or slugging in a fluidized bed, and restricted flow of annulus solids or instability in a spouted bed. The spout-fluid bed technique gives a much higher rate of circulation and mixing of solids and fluid than any other technique for fluid-particle contact. I t allows a larger range of fluid flow rate and good control of spouting or fluidizing. The minimum fluid mass flow rate for maintaining spouting or fluidizing is lower than when the entire bed is only spouted or fluidized.
Thirty-seven papers from a symposium sponsored by the Division of Fuel Chemistry and the Division of Physical Chemistry of the American Chemical Society, chaired by Bernard D. Blaustein.
Asok Chatterjee, Indian Institute of Technology, Bombay-76, India IND. ENG.CHEM.PROCESS DESIGN DEVELOP. 9,338-339 (1970)
A wide range of topics are covered in these papers by clhelm. ists, physicists, and engineers including treatments of de-
SELECTIVE CATALYTIC REMOVAL OF AMMONIA FROM GASES CONTAINING ACRYLONITRILE
Bismuth phosphomolybdate is a n effective catalyst for the vaporphase selective oxidation of ammonia in the effluents of the propylene ammoxidation reaction. Such a n oxidation required very different reaction parameters of temperature, contact time, and gaseous linear velocity from those necessitated for propylene ammoxidation. U p to 90% of the ammonia was oxidized, while acrylonitrile was little affected.
composition and dissociation reactions, ion-molecule reactions, chemical syntheses, and chemical engineering aspects and physics of reactions in electrical discharges.
514 pages with index
Clothbound
(1969)
$15.00
S. C. Malhotra, E. I. du Pont de Nemours €3 Go., Gibbstown, N . J . IND.ENG.CHEM.PROCESS DESIGN DEVELOP. 9,340-341 (1970) FOAM BREAKING WITH A HIGH SPEED ROTATING DISK
Experimental data are presented on the effectiveness of two configurations of mechanical foam breakers, both based on the shearing action of a high-speed rotating disk. For foams impinging on a given small area on top of the disk experimental data yield a n empirical equation relating exit foam and liquid flow rate to inlet foam flow rate rotational speed and distance from center of rotation, and an empirical equation for the critical rotational speedLe., the rotational speed above which all the foam impinging on the disk collapses. Experimental data on the foam-breaking capacity of a rotating disk located in a pipe with the foam impinging on the complete disk area indicate that this configuration can serve as an effective foam breaker.
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Eliezer Rubin and Michael Golt, Technion-Israel Institute of Technology, Haifa, Israel IND. ENG.CHEM.PROCESS DESIGNDEVELOP. 9, 341-344 (1970) VOL. 6 2
NO. 4 A P R I L 1 9 7 0
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