CALCULATION METHOD FOR EVALUATING THE SEPARATION PERFORMANCES OF HOLLOWFIBER MEMBRANE N_2-H_2 SEPARATORS

A mathematical model for evaluating the separation performances of hollow-fiber membrane N_2—H_2 separators has been established. The influences of operating parameters and membrane characteristics on the hydrogen concentration of the permeated gas and the percentage recovery of hydrogen have been studied with the help of a digital computer using this model. The correctness of the model is proved by comparing the calculation results with the data obtained from the field test of three φ100×3000mm industrial scale separators.     

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.     

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.     

STUDY ON THE DIFFUSION OF Cu~(2 )-H~ COUPLE IN A CATION EXCHANGE MEMBRANE——A RAPID METHOD TO DETERMINE SELF-DIFFUSION COEFFICIENTS OF COUNTER-IONS WITH UNEQUAL VALENCE

1 INTRODUCTIONKnowledge of the basic transport phenomena of ions in an ion exchange membrane isimportant for the application of such a membrane.Various studies on the developmentof mathematical models for predicting and correlating membrane transport rate havebeen published in recent years.More exact estimation of the diffusion coefficientshas been the subject of chief concern in many of these papers.For a bi-ionic systemwith the same valence,Sato et al.gave a method for estimating diffusion coefficients in     

A METHOD OF GREEN’S FUNCTION FOR THE UNSTEADY STATE SOLUTION OF A DISPERSION TYPE TUBULAR REACTOR MODEL WITH AN IMMOBILE ZONE

A general unsteady state solution is obtained by means of Green’s functions for a dispersion-typetubular reactor model with an immobile zone.Arbitrary initial concentration profiles along the reactorfor the flowing zone and the immobile zone are allowed and the feed concentration is time-varying.Firsta self-adjoint operator is defined and then the Green’s function is determined.The solution is finally con-structed from the Green’s function.     

"LEAST-SQUARES FITTING METHOD IN THE TIME DOMAIN"FOR THE STUDY OF AXIAL MIXING IN THE EXTRACTION COLUMN

An imperfect pulse injection stimulus-response technique and an on-line computer system are usedto improve the experimental and data processing technique in the study of axial mixing in the pulsed-sieve-plate extraction column.Comparison of different methods for parameter estimation proves that the“Least-squares fitting method in the time domain”is superior to the moment method and some weightedmoment methods.The uncertainty in parameter estimation is discussed.The effects of pulsation onthe axial mixing coefficient of single phase flow in the column are examined.     

A NEW METHOD FOR MEASURING THE LOSS OF CURRENT EFFICIENCY OWING TO CATHODIC SIDE REACTION IN CHLORATES PRODUCTION

A double cathode composed of a Ni screen cathode and a porous gas diffusion oxygen cathode with a porous diaphragm in between was constructed for the purpose of measuring the loss of current efficiency in an electrolytic cell for chlorate production. With this device the cathodic side reactions, i. e. reduction of ClO~-, HClO, etc., have been investigated, revealing the dependence of the loss of efficiency on the concentration of NaClO_3, the pH of the electrolytic solution and the presence of Na_2Cr_2O_7. The suggested method can also be applied to studying the side reactions and the loss of efficiency for the alkalichlorine cell and the electrolytic production of BrO_3~-, IO_3~-, ClO_4~-, etc.     

ON THE MINLP APPROACH FOR OPTIMAL DESIGN OF CHEMICAL ENGINEERING SYSTEMS (I) A GLOBAL OPTIMIZATION METHOD FOR NONCONVEX MINLP PROBLEMS

An algorithm for global optimization of a class of nonconvex MINLP problems is devel-oped and presented in this paper.By partitioning the variables,dual representation of the primal ofsubproblems and outer-approximation strategy are used to develop a representative relaxed iterativeproblem.Then the original MINLP problem is replaced by a series of subproblems and relaxediterative problems.By exploiting the particular form of the nonconvex MINLP problem,the feasibleregion of this problem is explicitly included in the representative problem,thus the inconvenienceencountered with the GBD method can be avoided.The proposed method is illustrated andinterpreted geometrically with an example problem.     

THE DEVELOPMENT OF A MANDREL PEEL TEST FOR THE MEASUREMENT OF ADHESIVE FRACTURE TOUGHNESS OF EPOXY–METAL LAMINATES

A mandrel peel test is established for measuring the adhesive fracture toughness of a metal/rubber-toughened epoxy laminate system. By adopting an energy balance analysis it is possible to determine directly both adhesive fracture toughness and plastic work in bending the peel arm around the mandrel. The suitability of the procedure is examined for various types of metal peel arms, which are classified in terms of their ability to deform plastically during the test. The plastic work is also predicted theoretically, and comparisons are made between the measured and calculated values. The fracture energies determined from the mandrel tests are compared with those obtained from 90° fixed-arm peel tests. For the calculations of plastic work in bending in the fixed arm test, various options are used when modelling the tensile stress-strain behaviour of the peel arm material. In addition, the adhesive layer thickness is considered in terms of its influence on the calculation of adhesive fracture toughness.     

A NEW METHOD FOR ACHIEVING DROPWISE CONDENSATION (Ⅲ) DETERMINATION OF DROPWISE CONDENSATION HEAT TRANSFER COEFFICIENT AND LIFETIME TEST OF THE NEW SURFACE

Heat transfer characteristics of the new surfaces were determined through temperature measurements, and the results were compared with dropwise condensation (DWC) studies from various sources.Duration tests for DWC were carried out on two different surfaces, giving a duration of perfect DWC over 15000 hours.     

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-     

A NEW PROCESS FOR THE EXTRACTION OF PENICILLIN G FROM THE FILTRATE OF FERMENTATION BROTH WITH TBP IN BUTYL ACETATE

The mixture of neutral phosphorus esters and butyl acetate (BA) can be used, as the extractant for the extraction of penicillin G. The extraction equilibrium pH can be increased to pH3—4 due to the stronger extraction capability of the solvent mixture, instead of pH1.8—2.2 with butyl acetate as solvent. The experimental results indicate that the total recovery of penicillin G can reach 96.6% with the new extraction process, which is 5—6% higher than that obtained with the traditional process using BA as solvent at pH1.8—2.2.