Summary of papers published in this month's research quarterly, IMEC

Summary of papers published in this month’s research quarterly, I M E C Fundamentals

THERMODYNAMICS OF SQLUTIONS WITH PHYSICAL AND CHEMICAL INTERACTIONS. SOLUBILITY OF ACETYLENE IN ORGANIC SOLVENTS

ENGINEERING STUDY OF CONTINUOUS POLYMERIZATION OF ACRYLIC MONOMERS

A set of thermodynamically consistent equations has been developed for representing the properties of solvating binary liquid mixtures. Chemical interactions between soIute and solvent are taken into account by K , a n equilibrium constant for complex formation; physical forces between solute, solvent, and complex are represented by van Laar equations through a single physical interaction parameter, 01. Solution of the resulting equations by iterative techniques for typical, physically significant values of K and 01 demonstrates that a wide range of mixture behavior can be represented. Literature data for solubility of acetylene in a variety of solvents have been analyzed and best values of K and CY are reported for 13 solvents. The new set of equations give a better fit of the data than that obtained using common two-parameter equations for the excess Gibbs energy. The method developed here can be extended to a variety of cases with strong specific interactions; it provides a basis for general treatment of strongly nonideal liquid mixtures.

Continuous free radical bulk and solution polymerization of acrylic monomers, methyl methacrylate in particular, is described. Consideration is given to appropriate kinetic models, and the experimental data from a pilot plant scale, two-stage continuous reactor system are presented. Agreement between the experimental and calculated results is reasonably good. The study is further amplified by a simple analoq computer simulation of the kinetic network superimposed on the conservation equations. Trial and error computer adjustments of the kinetic constants provided much clearer insight into the more complicated kinetic systems.

J . F. Terenzi and H. F. Coswa2, American Cjanamid Co., Stamford, Conn. 06904

IND.ENG.CHEM.FUNDAMENTALS 8, 199-205 (1969)

H. G. Harris and J . M . Prausnitz, U n i u e r s i ~of Calafornia, Berkeley, Calli. 94720 IND.ENC.CHEM.FUNDAMENTALS 8 , 180-188 (1969)

LIMITING BEHAVIOR OF THE TRANSVERSE TURBULENT VELOCITY FLUCTIJATIONS CLOSE TO A WALL

In previous studies of turbulent flow in a pipe the component of the fluctuating velocity gradient a t the wall in the direction of mean flow has been measured by determining the limiting current to a small rectangular polarized electrode mounted flush with the wall and oriented perpendicular to the flow. By measuring the limiting current a t a n electrode at 12i/20 to 20’ as well as at 90’ the rootmean-squared value of the component in the transverse direction has been estimated to be about 0.087 of the time-averaged velocity gradient at the wall. This is in agreement with recent photographic measurements of solid particles close to a wall made by Fowles. These results suggest that the limiting behavior of the eddy diffusion coefficient close to a wall is such that e m y 3 asy +-0, unless fluctuations in the m a s transfer rate are uncorrelated with fluctuations in the gradient of the transverse velocity component.

EXACT WEIGHT FRACTION DISTRIBUTION IN LINEAR CONDENSATION POLYMERIZATION

Since the so-called weight fraction distribution derived by Flory is approximate in the general case, this paper extends the Flory equations to give the true weight fraction distribution over the full range of molecular weight and polymerization parameters for linear condensation polymerization. Equations for true weight fraction are derived from the definition W , = M,A’,/2M,N,. Expressions for the x-mer molecules weight M , are derived as a function of x for case I with no product of elimination and for case I1 with a product of elimination during the condensation. For case I the socalled weight fraction is equivalent to the true weight fraction only for type i condensation or for type ii when r = 1. For case I1 it is never equivalent to the true weight fraction. Since the largest error occurs for small x-mers, the true weight fraction distribution is especially necessary for problems with a small average degree of polymerization 2,.

H. E. Grethlein, Dartmouth College, Hanouer, Ai. H. 03755 IND.END.CHEM.FUNDAMENTALS 8 , 206-210 (1969)

Kamalesh K. Sirkar and Thomas J . Hanratty, University of Illinois, Urbana, Ill. 61801 IND.END.CHEM.FUNDAMENTALS 8, 189-192 (1969) MEASUREMENT OF EFFECTS OF MIXING OF CHAIN CENTERS IN A NONUNIFORMLY INITIATED PHOTOPOLYMERIZATION

The effects of nonlinear equilibrium and axial mixing on sorption processes in packed ion exchange resin beds have been studied by digital computer simulation of column performance. Results show clearly that the presence of these effects leads to false estimates of apparent intraparticle diffusivities when a linear model is used in analyzing data. A technique for estimation of true diffusivities from apparent values is presented.

Apparatus has been developed for the study of effects of mixing of chain centers in nonuniformly initiated photoreactions. The experimental method is based on the use of a quartz reaction vessel, partially illuminated with ultraviolet light, equipped with a stirrer, and outfitted otherwise as a dilatometer. I n preliminary experiments involving the direct photo-initiated bulk polymerization of methyl methacrylate, the rate of polymerization varied with stirring speed, effective optical thickness, and incident intensity approximately in accordance with theoretical predictions. Evidence was found for the presence of spurious initiators, and for a hysteresis effect, resembling the result of the compounding of effects of viscosity and mixing. Methods of overcoming these difficulties were suggested.

C. J . Colwell and J . S. Dranof, Northwestern Unzversity, Euanston, Ill. 6020 7

Lowell Yemin and F. B . Hzll, Brookhauen Nattonal Laboratory, Upton, N . Y . 17973

IND.ENC.CHEM.FUNDAMENTALS 8, 193-198 (1969)

IND.

NONLINEAR EQUILIBRIUM AND AXIAL MIXING EFFECTS IN INTRAPARTICLE DIFFUSION-CONTROLLED SORPTION BY ION EXCHANGE RESIN BEDS. COMPUTER ANALYSIS

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CHEMISTRY

END.CHEM. FUNDAMENTALS 8, 210-215 (1969)

GENERALIZED RELAXATION METHOD IN CHEMICAL KINETICS

The relaxation method, originally developed by Eigen, applies only to reactions in a batch reactor. Furthermore, if the over-all reaction under study includes more than one independent reaction, the relaxation times of the component steps must be substantially separated from each other, usually a n order of magnitude, if various relaxation times are to be determined from the experimental data. I n this paper, the relaxation method is generalized so that it can be used in analyzing data obtained in a flow reactor with perturbed flow rate. I t works well where the relaxation times are close to each other. The method involves obtaining zeroes and poles of the frequency response information directly from frequency response experiment, or from transient response to pulse disturbance via numerical Fourier transformation. Various rate constants can be obtained from the zeroes and poles and equilibrium constants. Computer-generated “experimental” data demonstrate the usefulness of this method.

Richard W . Arbesman and Young Gul Kim, Northwestern University, Evanston, 111. 60201 IND.END.CHEM.FUNDAMENTALS 8, 216-221 (1969)

PARAMETRIC PUMPING. THERMAL MODE

SEPARATIONS VIA DIRECT

R. W. Rolke, Shell Development Co., Emeryville, Calif., and R. H. Wilhelm, Princeton University, Princeton, N . J . 08540


USE OF RESIDUALS IN THE IDENTIFICATION AND CONTROL OF TWO-INPUT, SINGLE-OUTPUT SYSTEMS

Linear and nonlinear identification techniques are examined for the feedforward control of chemical engineering systems with measurable load disturbances. The method developed by Narendra and Gallman to establish the polynomial gain function followed by a pulse transfer function, is extended to two-input systems through the consideration of residuals. The resulting iteration procedure, which alternately estimates the coefficients of the two parallel single-input branches, exhibits rapid convergence and yields an unbiased estimate for the model of the entire system. This identification procedure, used in conjunction with a feedforward control algorithm, is tested experimentally with a heat exchanger. The water flow rate disturbances can be compensated by adjusting the steam flow rate to yield the desired temperature of the heated water.

R. G. Corlis and Rein Luus, University of Toronto, Toronto 5, Canada

A computational investigation of separations by direct thermal mode, liquid phase parametric pumping is presented. Calculations are performed using the new STOP-GO algorithm, a modification of the method of characteristics. Using the toluene-heptanesilica gel system, we determined the effect of displacement, cycle time, phase angle, and reservoir volume on separations. Separation factor increases exponentially with number of cycles, and in the case of equilibrium operation, there is almost no limit to separation capability. We have simulated experimental separations presented previously by the authors. A graphical calculation procedure also is presented for equilibrium operation.

N . H. Sweed and R. H. Wilhelm, Princeton University, Princeton, N. J . 08540 IND.ENG.CHEM.FUNDAMENTALS 8, 221-231 (1969)

PARAMETRIC PUMPING AND THE LIVING CELL

Wilhelm suggested that parametric pumping might serve as a candidate model for active biological transport. In scaling the model to cell dimensions one encounters several difficulties. I t is not easy to fit a process of this kind into the biological membrane, as in doing so the number of adsorbent sites must be drastically reduced. Perhaps this decrease of effective sites will make the process inefficient on the biological level. The next difficulty has to do with the coupling of the oscillatory fields. While oscillatory electrical fields of high frequency a t the cell surface are easily conceivable (and perhaps measurable), oscillatory mass transfer fields of high frequency are less likely in the very few (if any) pores of the biological membrane. Beside the experimental approach indicated by Wilhelm, a computational approach, aimed a t scaling the mathematical model to a low number of adsorbent sites, might serve as a basis for verification or rejection of the model.

Hein L. Booaj, Unzuersity of Leiden, Leiden, The Netherlands INDENC.CHEM.FUNDAMENTALS 8 , 231-235 (1969)

RECUPERATIVE PARAMETRIC PUMPING. EXPERIMENTAL EVALUATION

trolled and alternating in direction, intraparticle profiles must be taken into account.

MODEL DEVELOPMENT AND

A computational model, based on finite difference solution of partial differential equations, is developed to describe thermal and solute concentration behavior within a recuperative parametric pumping column. Experimental data for the dilute NaCl solution-mixed bed ion exchange resin system are used to evaluate parameters in the model, which successfully simulates the time- and position-varying column profiles during an experimental NaClH20 separation run. T o model accurately this system in which interphase solute transfer is strongly intraparticle diffusion-con-

IND.ENC.CHEM.FUNDAMENTALS 8, 246-253 (1969)

OPTIMAL FEEDFORWARD-FEEDBACK CONTROL OF DEAD TIME SYSTEMS

Optimal composite feedforward-feedback controllers for multivariable chemical systems can be obtained by using the parametric expansion technique to solve the dynamic programming equations which were used to formulate the optimization problem. Separable random load disturbance signals are considered because of simplifications important in practical controller design. The Smith linear predictor configuration is a natural result of this optimal design technique. This controller design method appears to be a powerful tool for a wide variety of process control problems.

E?. H. West and M . L. McGuire, University of Oklahoma, Norman, Okla. 73069

IND.END.CHEM.FUNDAMENTALS 8, 253-257 (1969)

CONTROL OF NONLINEAR STOCHASTIC SYSTEMS

The control of nonlinear lumped-parameter dynamical systems subject to random inputs and measurement errors is considered. A scheme is developed whereby a nonlinear filter is included in the control loop to improve system performance. The case of pure time delays occurring in the control loop is also treated. Computations are presented for the proportional control on temperature of a CSTR subject to random disturbances.

John H. Seinfeld, George R. Gavalas, and Myung Hwang, Chemical Engineering Laboratory, California Institute of Technology, Pasadena, Caly. 91709 IND.ENG.CHEM.FUNDAMENTALS 8, 257-262 (1969)

TURBULENT LIQUID MIXING. ASSOCIATED SCALAR SPECTRA AND LIGHT-SCATTERINO MEASURE

Mixing of two miscible liquids in turbulent flow was studied using laser-generated light as the discriminating tool. Time averaged light scatter measurements give directly a spectrum for spatial variations in concentration. The measured dependence of this spectrum upon the decay time during which concentration variations are dissipated serves to characterize the mixing process.

D. E. Christiansen, Princeton University, Princeton, N . J . 08540

IND.ENC.CHEM.FUNDAMENTALS 8, 263-271 (1969) VOL. 6 1

NO. 5 M A Y 1 9 6 9

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WAVES AT SURFACES OF FLUIDIZED BEDS. SIMPLE MODEL OF A FLUIDIZED BED

APPLICABILITY OF A

I n an attempt to determine the applicability of some simple fluid dynamical models of fluidized beds, wave length and frequency were measured for waves at the top surface of air-fluidized beds of 74- to 104-micron Aerocat catalyst and 149- to 177-micron glass spheres, and attenuation rates of surface waves for the bed of glass spheres. Since agreement with the predictions of Rice and Wilhelm was good, their model is proposed as a useful fluid dynamical approximation to gas-fluidized beds of light to moderate density particles. Further verification is provided by good agreement of bed viscosities predicted by this model and measurements by a Brookfield viscometer on the catalyst bed. R. G. Finnerty, Jr., J . R. M a a , A . M . Vossler, H. 5'. Yeh, W . W. Grouse, Jr., and W . J . Rice, Villanova University, Villanova, Pa. 19085 IND.END.CHEM.FUNDAMENTALS 8 , 271-278 (1969) AXIAL MIXING OF A LOW VISCOSITY LIQUID IN A WIPED-FILM EVAPORATOR

The effect of axial mixing on the separation efficiency of a wipedfilm evaporator is presented for a binary distillation. Peclet numbers, based on the feed velocity, are estimated from residence time distributions of water.

D.E . Clemons, Shell Development Go., Emeryville, Calif. 94608

as the concentration driving force increased. The amplitudes and periods measured were larger than predicted by theory, although in qualitative agreement with predicted magnitude trends as a function of concentration driving force.

Benjamin Gross and A . Norman Hixson, Unioerrity of Pennvlvania, Philadelphia, Pa. 79104 IND.ENG.CHEM.FUNDAMENTALS 8, 296-302 (1969) INTERACTIONS OF REACTION AND DIFFUSION IN OPEN SYSTEMS

Asymptotic stability of uniform, nonequilibrium stationary states in multicomponent systems communicating everywhere with uniform surroundings is analyzed. Conventional diffusion with first-order reactions is mathematically equivalent. The systems need not be close to equilibrium. Conditions are given under which stability is completely determined by eigenvalues of the matrices of reaction constants and diffusion coefficients separately ; commuting reaction and diffusion matrices are a special case. Reaction and diffusion may interact to produce instability where neither does by itself. Stability behavior with more than three components is analytically intractable, but a complete catalog for two components and representative results for three are presented. How to design in principle a three-component system having specified stability behavior is shown. Implications for n-component systems are discussed, especially systems that can be approximated by a number of weakly interacting subsystems.


H. G. Othmer and L. E. Scriven, University of Minnesota, Minneapolis, Minn. 55455

ITERATIVE PROCEDURE FOR SOLUTION OF SYSTEMS OF PARABOLIC AND ELLIPTIC EQUATIONS IN THREE DIMENSIONS


An iterative procedure has been developed to solve systems of three-dimensional elliptic and parabolic differential equations. The two-equation algorithm has been tested on an oil reservoir flow problem. The procedure is fast, is insensitive to rounding errors, and in very difficult problems it yields a solution where a procedure such as the alternating direction technique cannot. For the problem tested, a reliable set of iteration parameters is easily calculated from the coefficient matrix.

IMPROVED METHOD OF ANALYZING CURVES IN DIFFERENTIAL SCANNING CALORIMETRY

H . G. Weinstein, H. L. Stone, and T . V . Kwan, Esso Production Research Co., Houston, T e x . 77001

A new technique for analyzing data which appears to improve the use of the traces obtained by differential scanning calorimetry is based on a procedure for obtaining the true heat capacity base line for a system undergoing a thermal event, allowing enthalpy change to be isolated from heat capacity contributions. Experimental data on cotton and poly(methy1 methacrylate) illustrate the resulting improvement in determination of enthalpy changes, peak temperatures, and kinetic data.


W. P. Brennan, Bernard Miller, and J . C. Whitwell, Princeton University, Princeton, N . J . 08540

MARANGONI INSTABILITY WITH UNSTEADY DIFFUSION IN THE UNDISTURBED STATE


The theory of interfacial turbulence accompanying mass transfer has been extended to include unsteady-state diffusion in the undisturbed state, and resistance to transfer across the interface. The characteristic equations derived for the general diffusion case predict that the growth rate of a disturbance should increase and its amplitude decrease with both increasing driving force and closer approach to the steady state from below. Numerical results show that a system exhibiting resistance to transfer at the interface may be unstable with transfer in either direction. The fact that some of these predictions have been experimentally verified argues well for the theory.

LlOUVlLLE EQUATIONS FOR AGGLOMERATION AND DISPERSION PROCESSES

Benjamin Gross and A . Norman Hixson, University of Pennsylvania, Philadelphia, Pa. 19104 IND.ENG.CHEM.FUNDAMENTALS 8, 288-296 (1969)

The probability distribution of a collection of discrete subsystems, or particles, has a density which satisfies a continuity equation, or Liouville equation, described here for particles undergoing collisional interactions. From this equation, a set of equations for the moments of the distribution is derived. Solution of these moment equations by expansion in series of orthogonal functions is applied to coagulation processes in shear flow and to chemical reaction in coalescing dispersed media. Approximation methods applicable to realistic problems are described which require much less numerical computation than direct numerical methods.

H . M . Hulburt and Tetsuo Akiyama, Northwestern University, Evanston, Ill. 60201 IND.ENG.CHEM.FUNDAMENTALS 8, 319-324 (1969)

A N INTERFEROMETRIC STUDY OF INTERFACIAL TURBULENCE ACCOMPANYING MASS TRANSFER. WATER-ACETIC ACIDBENZENE

DIFFUSION KINETICS AND CATALYST ATTRITION IN CYCLIC PROCESSES

Interfacial turbulence accompanying mass transfer was studied for the system benzene-acetic acid-water using a diffusion cell in which steady-state conditions could be attained. A continuous film record of the transfer process in both unsteady- and steady-state regimes was made using a four-beam interferometer powered by a laser beam light source. Over-all concentration differences of 5 , 10, and 307, acetic acid were used. Motion a t the interface was observed during unsteady- and steady-state transfer. The frequency of the disturbances increased and the amplitude decreased

In catalytic cracking with circulating solid catalyst, a curious dependence of the mechanical particle attrition rate on the nature of the regeneration kinetics can occur. Sharp radial gradients in residual carbon concentration can result from heavily diffusioninhibited coke-burning rates. Structural aging processes create internal strains in the resulting particles with nonisotropic carbon contents and lead to mechanical fracturing. Attrition rates in the commercial T C C process were markedly reduced by the development of bead catalyst having nearly doubled diffusivity

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INDUSTRIAL A N D ENGINEERING CHEMISTRY

BRIEFS (Durabead) without change of chemical composition. Analogous phenomena can occur in other cyclic catalytic processes.

P. B. Weisz, Mobil Research and Develoflment Gorp., Princeton, N . J . 08540

IND.ENG.CHEM.FUNDAMENTALS 8 , 325-329 (1969) FREE CONVECTION AT LOW PRANDTL NUMBERS IN LAMINAR BOUNDARY LAYERS

sites at the window between supercage and sodalite cage. It is concluded that such sites, if present a t all, must represent a fraction less than about 10-7 of all the sites available to krypton. Thus, the large electrostatic fields associated with these bivalent cation sites play an insignificant role in the adsorption of krypton. Similar conclusions have been reached by measuring qat on Y samples containing Mg2+, SrZi, Ba2+,and Fez+. I t is proposed that krypton is adsorbed a t effectively univalent sites consisting of a single M a + associated with OH- or of two M2+ions bridged by 02-ion, depending on the degree of dehydroxylation of the sample.

Y . Y. Huang, J . E. Benson, and M . Boudart, Stanford University, Stanford, Cal?. 94305

A two-term expansion is derived for the Nusselt number for laminar, natural convection about an isothermal, horizbntal cylinder immersed in a fluid of vanishingly small Prandtl numbers. The analysis is carried out for round-nosed cylinders but may be applied to cylinders of other shapes simply by reinterpretation of the independent variables. A numerical result is derived for a circular cylinder and used together with prior theoretical results for Pr 0.7 and 03 to construct an interpolation formula for all Pr. This formula agrees well with experimental and theoretical results for Pr 0.01. I t is concluded that one- and two-term expansions of the type previously developed by the authors are adequate for small as well as large Prandtl numbers.

IND.ENG.CHEM.FUNDAMENTALS 8 , 346-353 (1969)

D . A . Saville, Princeton University, Princeton, N . J., and S. W . Churchill, Universaty of Pennsylvania, Philadelphia, Pa. 79104

Raymond W. Flumerfelt, Mark W. Pierick, Stuart L. Cooper, and R. Byron Bird, Universily of Wisconsin, Madison, Wis. 53706



SUFFICIENT CONDITIONS FOR STABILITY OF FLUID MOTIONS CONSTITUTIVELY DESCRIBED BY THE INFINITESIMAL THEORY OF VISCOELASTICITY

An energy method is employed to determine sufficient conditions for the stability of fluid motions which are constitutively described by the infinitesimal theory of viscoelasticity. The analysis is restricted to situations for which the fluid is either totally confined by solid walls or the velocity field for the disturbed fluid motion may be assumed to be periodic along an axis of symmetry. The sufficient conditions for stability established appear to be somewhat conservative. For the conditions to yield nontrivial information, the fluid memory must have a Newtonian aspect to it such that emphasis must be placed on events occurring at the present time.

Martin R. Feinberg and William R. Schowalter, Princeton University, Princeton, N . J . 08540 IND.ENG.CHEM.FUNDAMENTALS 8, 332-338 (1969) SOME PROBLEMS IN CHEMICAL REACTOR ANALYSIS WITH STOCHASTIC FEATURES. LINEAR SYSTEMS WITH FLUCTUATING COEFFICIENTS

The best yield of B from the reaction sequence A -t B -L C requires the correct choice of reaction time in the batch or of holding time in a stirred tank reactor. This choice depends not only on rate constants but also on the intensity of the random fluctuations in the conditions. For both reactors, the optimal time is calculated as a function of the variance of the temperature fluctuations, and the stirred tank fluctuations in the flow rate are also considered.

T. M . PeU, Jr., and Rutherford Aris, University of Minnesota, Minneapolis, Minn. 55455 IND.ENG.CHEM.FUNDAMENTALS 8, 339-345 (1969)

KRYPTON AS A PROBE OF ELECTROSTATIC FIELDS IN Y ZEOLITES

The isosteric heat of adsorption, qat, of krypton on an 82y0 Caexchanged Y zeolite was obtained a t a surface coverage corresponding to about one krypton per 64 supercages. The value of qat,calculated from adsorption isotherms taken at pressures between 5 and 180 torr and temperatures between 0" and 150°C.,was found to be 5.3 kcal. per mole after prior evacuation of the adsorbent a t 41OOC. and 4.6 kcal. per mole when the sample was heated to above 7OOOC. in vacuo before adsorption. These values must be compared with a calculated heat of adsorption of about 20 kcal. per mole, largely due to polarization energy if krypton were adsorbed at Ca2+ion

GENERALIZED PLANE COUETTE FLOW OF A NON-NEWTONIAN FLUID

A non-Newtonian fluid is in steady-state, laminar flow between two infinite parallel flat surfaces, one of which is in motion; in addition there is a pressure gradient acting in the same (or opposite) direction to the motion of the bounding surface. For this problem the velocity profiles, volume rate of flow, and force on the surface are found. A power-law function is used to describe the non-Newtonian viscosity. A numerical table facilitates numerical calculations.

COMMUNICATION. ZONE REFINING CONSIDERED AS A MULTISTAGE SEPARATION METHOD

Some aims are suggested for a science of separations which seeks to unify the understanding of diverse multistage separation methods. Zone refining, examined in this context, is found to be an unusual type of equilibrium separation method in which multistage separation is achieved without conventional countercurrent flow and reflux.

W. G. Pfann, Bell TelephoneLaboratories, Inc., Murray Hill,N . J . 07974 IND.ENG.CHEM.FUNDAMENTALS 8, 357-358 (1969) COMMUNICATION. CONCENTRATION POLARIZATION IN REVERSE OSMOSIS UNDER NATURAL CONVECTION

Concentration polarization in the desalination of salt water by reverse osmosis is investigated for the case in which the deslination membrane is a vertical flat plate. An expression for the concentration of salt at the surface of this membrane is obtained by expanding the solution of the governing laminar boundary layer equations for natural convection about the leading edge of the plate. This expression, together with a n equation for the membrane concentration at large distances from the leading edge, can be used then to predict the polarization effect a t any point along the membrane.

A . R. Johnson and A . Acrivos, Department of Chemical Engineering, Stanford University, Stanford, Galq. 94305

IND. ENG.CHEM.FUNDAMENTALS 8, 359-361 (1969) COMMUNICATION. AXIAL MIXING AND SELECTIVITY. CONSECUTIVE FIRST-ORDER REACTIONS

TWO

For reaction systems with linear kinetics, the performance of nonideal reactors can be accurately calculated by a simple numerical integration of the residence time distribution. Experimental residence time distribution data were used to calculate reactor performance for a system of two consecutive first-order reactions. Mixing pwameters for the dispersion and the CSTR cascade models were obtained from the variances of the residence time distributions. Model predictions gave excellent agreement with the integration results over a wide range of mixing intensity. Reactor selectivity was strongly dependent on mixing and reaction kinetics.

Carlos B. Rosas, Merck Sharfl €Y Dohme Research Laboratories, Rahway, N . J . 07065

IND.END.CHEM.FUNDAMENTALS 8 , 361-364 (1969) VOL. 6 1

NO. 5

MAY 1969

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Summary of papers published in this month's research quarterly, IMEC

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