A mathematical model for discribing the start-up period of a plate distillation column operating undertotal reflux is presented.Based on the differential-difference equation expressing the material balance onthe trays in a complete column with holdups in the reboiler,trays and condenser,the present model isderived and an analytical solution is obtained.The existence of a constant concentration point during thestart-up period is proved mathematically.Experimental work on start-up period is carried out in a seven sieve tray distillation column of 0.17meter in diameter with a water-acetic acid system.Good agreement is found between the experimentaldata and the calculated results.The experimental results also show the evidence of a constant concentra-tion point in the column during start-up period.

The asymptotic solution of isothermal effectiveness factor for one dimensional catalyst pellet can bedetermined by use of perturbation method when Thiele modulus is very large or very small.Taking theinformation given by these asymptotic solutions,a new approximate expression of effectiveness factor hasbeen derived as follows(?)This expression is feasible for the whole range of Thiele modulus and its accuracy is very satisfactoryin comparsion with the exact solution obtained for first order reaction.The physical meaning of the as-sumptions given to the above expression of the system has been fully considered,so that the main defectsencountered in the approximate expressions published in literature have completely been overcome.Ourexpression can be conveniently applied to most of the practical calculations with reliability.

Large amounts of calculations on effectiveness factor have been done based on the approximateexpression proposed in Part(Ⅰ)of this work for porous catalyst under isothermal condition at various valuesof Thiele modulus for nonfirst order reaction of power-function and hyperbolic kinetics.Likewise,valuesof effectiveness factor have been obtained under the same conditions from the three expressions found inliterature as well as by numerical method for comparison.The results show that our approximate expressionhas a quite high accuracy and therefore is much superior to the others.The parameter estimation of ourexpression is rather easy doing and has no such difficulties as encountered in handling of the other ex-pressions.

In applying computation technique to improve the operation of existing chemical processes,a computer-aided process optimization method is proposed——the improved two-tier method based on SuccessiveQuadratic Programming(SQP).By inserting extra variables in SQP,a new quadratic programming prob-lem is constructed,and a decomposition strategy for the quadratic programming is also pressented,whichhas been found to be always feasible when the matrix is singular.This new two-tire method based onSQP has better performance both in numerical stability and in convergence behavior.Satisfactory resultis obtained in applying this algorithm to optimize a methanol synthesis process,thus leading to implemen-tation in actual practice.

An experimental apparatus was set up for the measurement of gas solubility in liquids.The solubilitydata of pure hydrogen chloride and chloromethane in the temperature range of 293-323 K and pressurerange of 6-130 kPa and those of the mixture at 298.15 K were obtained and correlated with modifiedHenry’s equation.The activity coefficients were calculated with Margules’ equation.

This paper introduces a mathematical model and advances an algorithm,that can be used for simu-lation of reactive distillation processes.This model takes into account the reactions in series,that occurwithin a distillation column and this algorithm is based upon the block tridiagonal matrix technique.In order to accomplish a computation of design and inspect whether or not different configuration of flowsbetween stages can increase the yields of intermediate products,a procedure for solving block tridiagonalmatrix equation with some off-tridiagonal submatrixes and/or submatrixes on the borders is modified.The saponification of propylene chlorophydrin is illustrated to verify the algorithm.It can be seen thatthe results are satisfactory.

Bubble formation frequencies in a single orifice two-dimensional gas-solid fluidized bed(292mm×16 mm)were measured by means of a high-sensitivity capacitance probe.A spectrum analyzer was used toanalyze the bubble frequency distribution.The effects of a series of parameters,including particle size(0.105—0.590 mm),particle density (590-2990 kg/m~3),minimum fluidization velocity of particles(0.0072-0.481 m/s),initial bed height (205-565 mm),probe vertical location,jet gas flow rate(0.5-35×10~(-4)m~3s)and background fluidizing gas velocity (0-3 times of minimum fluidization velocity),on the bubble frequencypower spectrum density were investigated.For the fluidized bed with small particles of low density,the bubble formation frequency was in goodagreement with Davidson and Harrison model.The data showed a regular deviation from that model asparticle size and density increased.The model is then modified to account for the fact that with largeparticles,gas will leak from the forming bubble into the surrounding emulsion phase.The modifed leakagemodel agrees with the experimental results.

A physical model and a mathematical model were established in order to describe and improve the“vapor-phase resistance method”of Bell and Ghaly.Considering the effect of ripples at the interface onvapor-phase resistance,a correction factor v_ιwas proposed.Another factor (θ/π)βwhich correctsthe influence of the liquid pool along the bottom of the horizontal tube on the liquid-phase heat transfercoefficient was derived and the relationship of θand βwas correlated.The heat transfer coefficient pre-dicted by Bell’s method are approximately 10—15% lower than the experimental values if the effect ofripples on vapor-phase resistance has not been taken into account.The comparison of the predicted valuesof h_c from the modified vapor-phase resistance method with the experimental data showed a deviation of±10%.

Various rhenium compounds and activated Re_2O_7/Al_2O_33 catalysts were studied by negative ion fastatom bombardment mass spectrometry(FAB-MS).Analysis of the spectra indicates that on the surfaces ofthe catalysts,in addition to Re_2O_7,there are surface species characterized by Re_xO~-_y peaks with largenumbers of x and y,which could be precursors of active sites in metathesis.

In this paper the group concept and UNIFAC group contribution method have been discussed andextended.A method of on-line data processing for UNIFAC group interaction parameters based on therelevant component properties stored in data base has been proposed.Results of predicting vapor-liquid equilibria for 22 systems by on-line processing parameters are compared with those by original(off-line)parameters,the accuracy of prediction is improved considerably.

Liquid-liquid equilibrium(LLE)data have been determined for the n-butyl alcohol-water-butyl acetateternary system and the related binary systems at 293.15,303.15 and 313.15 K.The experimentally determinedLLE data for the n-butyl alcohol-water binary system have been found to be in satisfactory agreementwith the available literature data.The correlation and prediction of the LLE data have been done byusing NRTL and UNIQUAC models.The model parameters of binary systems have been identified witha thermodynamic criterion.In the correlation of ternary LLE data,two objective functions(mole fractionand distribution constant)have been used for purpose of comparison.The effect of weighting in the firstobjective function has been examined.In predicting the ternary LLE with different sets of parameter valuesobtained for each of the constitutent binary systems,improved prediction results have been obtained bycomparing the results of different combinations of the sets of parameter values and choosing those givingthe best result.

Ethylene glycol acetate can be prepared from ethylene by employing PdCl_2-CuCl_2-Cu(OAc)_2 in anacetic acid solution,usually involves two steps-acetoxylation and the regeneration of catalyst.In thispaper,a one-step process has been studied with oxygen and ethylene introduced simultaneously in a singlereactor.It was observed that there must be enough partial pressure of oxygen to oxidize Cu~+ to Cu~(2+)by keeping oxygen content at 8-10% in the raw binary gas mixture of oxygen and ethylene,whereby theactivity of the catalytic system could be maintained without formaton of CuCl residue.By using nitrogen as a diluent,the ratio of O_2/C_2H_2 could be kept in the non-explosive range.Itis claimed that 95% of the converted ethylene from the feed gas exists as ethylene glycol monoacetateand diacetate.