EASIER FORMULA DESIGNING FOR ALKYDRESIN WITH HELP OF COMPUTER

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THEORY FOR STEP AND PULSE METHOD OF SUPERCRITICAL FLUID CHROMATOGRAPHY

1 INTRODUCTIONSupercritical fluid chromatography(SFC),employing supercritical fluid as mobilephase,originated in the 1960's [1-4].Since 1980's extensive research work has beenperformed on SFC,chiefly for analytical purposes [5,6].SFC was then adopted for thedetermination of thermodynamic properties such as partial molar volume,and partialmolar enthalpy of solutes in both mobile phase and stationary phase and the solutedistribution coefficient between two phases [7- 11].Partial molar properties can be de-     

CORRELATION OF DIFFUSION COEFFICIENTS FOR LIQUIDS AND DENSE FLUIDS WITH TEMPERATURE AND PRESSURE

On the basis of the free volume theory and activation energy concept,a fundamental equation whichtakes into account the effects of temperature and pressure has been developed.By introducing differentexpressions for the free volume and activation energy,several equations for fluid diffusion coefficients were derivedaccordingly.With the van der Waals free volume and intermal energy formula,a three-parameter model for fluiddiffusion coeffficients at moderate pressure was obtained.The grand average absolute deviation percent of 345data points (44 systems)for self-and infinite dilute inter-diffusivities is 2.32,against the results of the model ofCohen and Turnbull,4.13.In particular,by means of the modified Carnahan-Starling free volume equation,afour-parameter model with average abosolute deviation percent 2.64(30 systems,644 data points)for theestimation of dense fluid inter-and self-diffusivities at high pressures and in supercritical conditions was derived.The derived model is superior to the method of L     

STUDY ON EBULLIOMETRIC METHOD AND LEANING EBULLIOMETER

The relation between the gravimetric liquid concentration (χ_(10)) and equilibrium one (χ_1) is developed for the system within an ebulliometer or a still operating steadily. From the relation, the necessary and sufficient condition for χ_(10)→χ_1, and a new equation for calculating limiting activity coefficient (γ~∞) are deduced. This equation proves more accurate than that proposed by previous researchers. The leaning ebulliometer, a new apparatus, is designed to measure bubble points and γ~∞ without composition analysis, its operating line (T, P, χ_(10)) proves a good approximation to the bubble-point line (T, P, χ_1): |(χ_(10)-χ_1)/χ)|<0.005|K_1-1|, where K_1=y_1/χ_1 is the K-value.     

STUDY ON CHROMATOGRAPHIC SLOPE METHOD FOR REDUCING PARAMETERS OF EXCESS GIBBS ENERGY MODELS

Two equations of (γ/χ)χ=0 ——a modified Kikic-Renon equation and a Valentin-Guiochon equation——have been studied. Values of γ_1~∞ and (dlnγ_1/dχ_1)χ=0 by these two equations for 29 binary systems have been calculated from GLC data, the parameters in some models of excess Gibbs free energy evaluated and the vapor-liquid equilibrium date predicted. The results are satisfactory.     

NEW GROUP-CONTRIBUTION CORRELATIONS FOR ESTIMATION OF CRITICAL PROPERTIES

New correlations based on group-contribution method for estimating critical properties have been proposed with con-tribution values of 67 groups.The new correlations have been examined by extensive comparison of the values calculatedwith the experimental data of 275 substanees.The average percent deviations of estimation of T_c,P_c and V_c are respective-ly 0.76,2.73 and 2.50 which are lower than those estimated by the Lydersen method and the Ambrose method chosenfor eomparision.     

VAPOR-LIQUID EQUILIBRIA FOR MIXTURES OF TOLUENE AND POLYSTYRENE WITH DIFFERENT MOLECULAR WEIGHTS

An experimental system for measuring the VLE of polymer solutions based on the staticvapor-pressure method has been established,VLE data for mixtures of toluene and polystyrene withdifferent molecular weight covering a wide range from 2.98×10~3 to 3.84×10~6 were obtained at 35℃.The reduced pressure p/p°versus weight fraction W plot is found to be independent on the molecularweight of the polymer within the experimental error.Calculated activity coefficients are also independenton the molecular weight.However,for the Flory-Huggins interaction parameter x,not only a strongconcentration dependence is observed,but also the molecular weight of the polymer exerts definiteinfluence.Generally,the parameter x slightly increases as the molecular weight of the polymer decreasesespecially when the molecular weight is low.The dependence of the parameter x on the molecularweight can be neglected when the molecular weight of polymer is greater than 1.00×10~4.     

ESTIMATION OF FIXED BED HEAT TRANSFER PARAMETERS WITH ORTHOGONAL COLLOCATION

Two heat transfer parameters in the fixed bed,radial effective conductiviw k_(er),and wall heat transfer coefficient h_ware estimated by using the method of orthogonal collocation and non-linear least square.The temperatures at forty collo-cation points distributed along the radial direction are measured simultaneously by means of multiehannel data logger.Theeffects of bed height,Re_p,d_t/d_p,gas inlet temperature and wall temperature on k_(er)and h_w are studied.The results indicatethat the effect of gas inlet temperature and wall temperature is negligible.Bed height will only influence the parameter es-timations in shallow bed and at low Re_p.Both k_(er)and h_w tend to reach a limit with increasing bed height.The asymptoticbed height which is independent of d_p is about 0.5 m,while the asymptotic values of k_(er)and h_w increase with d_p.The pa-rameters obtained with the wall being heated are about 10% lower than those with the wall being cooled.k_(er),h_w and stag-nant contribution terms k_(er)and h_w are all related to dp·k_(er)and h_w estimated at the asymptotic bed height are correlated bythe following equations:k_(er)=0.199+0.015 d_t/d_p+0.0020/(1+14.15(d_p/d_t)~2)Re_ph_w=33.4+4.23d_t/d_p+0.333/(1+8.54(d_p/d_t)~2)Re_p(5.5<d_t/d_p<13)(100<Re_p<500)     

KINETIC MODELING OF HYDROISOMERIZATION OF C\-8AROMATICS(Ⅰ)MODELING AND ESTIMATION OF RELATIVE RATE CONSTANTS BY THE WEI-PRATER METHOD

1 Introduetlon To date,most kinetie investigations ofC一aromaties hydroisomerization over bifunetionaleatalysts have been eoneerned with reaetjon meehanisms.R6bsehl巨ger et al.[,]studied thehydroisomerization kineties under sPecifie eonditions,and ProPose…     

A METHOD FOR CALCULATING THE EXTENT OF REACTION OF SOLID PARTICLES WITH FLUID IN COMPLETELY MIXED REACTORS CONNECTED IN SERIES

When solid particles react with a fluid,the overall rate is influened by the fraction of the solidunconverted as well as by the operating conditions such as temperature and pressure.Calculation of solidsconversion in the individual reactor of a multi-stage reactor system has therefore to be based upon thesolids residence time distribution (RTD) in the respective stages.By using either the Dirac function δ(0) or the probability density function of the sum of independentrandom variables,the solids RTD in any stage of completely mixed reactors connected in series with nointerstage backflow has been obtained.The latter method has also been used in deriving general formu-las for the calculation of solids conversion when the order of chemical reaction is simple.For complexchemical reaction rate equations a stagewise procedure for numerical computation is proposed,and twocases are discussed according to whether the rate equation is expressed in its integral or differential formrespectively.     

SIMPLIFIED FRAMEWORK FOR DESCRIPTION OF MIXING WITH CHEMICAL REACTIONS (Ⅰ) PHYSICAL PICTURE OF MICRO- AND MACROMIXING

1 INTRODUCTION When a fluid is injected into a turbulence field to mix with another fluid,twohomogenization processes take place simultaneously:micromixing(on the molecularscale)and macromixing(on the mixer scale).For micromixing,three successive stages arerecognized at high Schmidt number(1)turbulent dispersion,in which the original ma-terial lumps are dispersed by turbulence into discrete elements with smallest eddy sizeλ_k;(2)viscous deformation,in which the size of the elements is further reduced     

A MODIFIED VDW EQUATION WITH TEMPERATURE DEPENDENT PARAMETERS FOR CALCULATING OF ASSOCIATION AND POLAR FLUID

The generalized van der Waals(vdW)equation of state was proposed by Schmidt and Wenzel(1980)and later modified by Iwai,Margerum and Lu to improve its calculations of pure component liquid densities forthe polar fluid.In this paper,we present a modified vdW equation of state by introducing a new temperaturefunction for representing α(T)and considering u to be dependent on pure component property.     

CRITICAL ASSESSMENT OF VISCOSITY AND ITS CORRELETION WITH TEMPERATURE FOR GASEOUS SUBSTENCES UNDER NORMEL PRESSURE

The viscosity data of 61 gaseous substances under normal pressure are critically assessed.The datacollected were published either in the years from 1967 to 1979 for the fifty of the substances or from1960 to 1966 for the others.The mathematical expressions used in the literature for correlating viscositydata of gaseous substances with temperature are reviewed,systematized and selected to correlate thedata assessed.The constants of the selected correlations are determined by the method of least squareswith a digital computer.The values of viscosity calculated by these correlations are then compared withthe experimental measurements.For the four-constants correlations,η=A_0+A_1T+A_2T~2+A_3T~3(Ⅰ) and lnη=A_0+B_0lnT+B_1/T+B_2/T~2(Ⅱ),the overall per cent deviations are 0.160 and 0.157 respectively.Equation(Ⅰ) is recommended for simplicity of calculation.The two-constants correlations,η-KT~(3/2)/(C+T)(Ⅲ),η=A_0+A_1T(Ⅳ) and η=aT~n(Ⅴ) have nearly the same accuracy of estimating viscosity values.Equation(Ⅳ) is simple for use and equation (Ⅲ) can correlate data of wider temperature range with an overallper cent deviation of 0,460.     

A METHOD FOR SEPERATING VELOCITY FLUCTUATION AND TEMPERATURE FLUCTUATION IN THE COURSE OF MEASURING TURBULENT PARAMETERS

A double hot-wire method is adopted to separate the mixed signal of temperature fluctuation and velocity fluctuation appearing in high temperature turbulences. The relationships among the various coefficients in the sensitivity equation for measuring turbulent fluctuations with constant temperature hot wire anemometer are deduced. Once these equations are being related to the temperature fluctuation sensitivity equation of a constant current hot wire anemometer, the temperature fluctuation signal may be taken out from the mixed signal, then the turbulent velocity fluctuation signal and other main turbulent parameters may be obtained.     

VAPOR-LIQUID EQUILIBRIA FOR SALT-CONTAINING SYSTEMS BY EQUATION OF STATE——MEASUREMENT AND CORRELATION OF VAPOR PRESSURES FOR SALT SOLUTIONS WITH SINGLE SOLVENT

1 .Introduetion In illvestigation of salt effeet on vaPor一liquid equilibria,a caleulated Proeedure based onPseudo binary aPProach has received mueh attention in recent yearst,1.The 50‘alled‘Pseudobinary’means that a ternary solution eonsiting of solve…     

A SEQUENTIAL PROCEDURE FOR PRECISE ESTIMATION OF PARAMETERS IN KINETIC MODEL

For a determined mathematical model,it is not only necessary to obtain the estimates of parameters,but also their reliabilites.The present work deals with a sequential statistical design strategy for anexperimental program to obtain precise parameter estimetes for a nonlinear kinetic model.It aims at de-creasing the indeterminatness of the parameter estimates,in reducing the correlation between parameterestimates,and in inceasing the adequacy and accuracy of the model.The paper discusses the experimental design criterion for precise parameter estimates-the minimun vol-ume design criterion and the spherical shape design criterion,and the practical value of a sequential statis-tical design strategy.At last,an example was performed to precise estimate the parameters in the kinetic model of ammoniasynthesis reaction which was selected as being adequate in the previous work.Comparison of the results from the industrial unit and the corresponding values calculated with themodel using the estimates of parameters reveals the reasonable reliability of the model.