摘要:

AbstractConventional design procedures use physical reasoning to construct equations describing the system. To find the optimal design for some specified performance criterion, it is desirable to change these equations into inequalities so that generalized polynominal programming, a highly nonlinear optimization technique, can be used. For illustration, a chemical reactor system optimal design problem with 11 variables and 8 constraints is formulated as an equality constrained optimization problem, then transformed into an inequality constrained generalized polynominal program and finally solved on the computer.

ISSN:0008-4034    

DOI:10.1002/cjce.5450470401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractPublished kinetic data for commercial water gas shift catalysts are interpreted in terms of pore diffusional effects. The Arrhenius plots of apparent activity show the curvature typical of the transition from reaction to pore diffusion control and the apparent activities of different catalyst pellets vary quite widely. Effective diffusivity data are used to calculate intrinsic rate constants from the apparent activity data and it is found that the intrinsic activities of the catalysts considered are all similar. Furthermore the intrinsic activities, calculated in this way, give linear Arrhenius plots and activation energies which are in good agreement with values obtained experimentally using small catalyst particles (22–27 K. Cals). The effect of pressure on apparent catalyst activity is also discussed and it is shown that this effect may be accounted for satisfactorily by pore diffusional effects and it is not necessary to assume a change in the intrinsic rate equation at least at pressures below 20 atm

ISSN:0008-4034    

DOI:10.1002/cjce.5450470402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

ISSN:0008-4034    

DOI:10.1002/cjce.5450470403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

ISSN:0008-4034    

DOI:10.1002/cjce.5450470404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThis note reports on some aspects of the effect of shell side baffle geometry on the dynamic behaviour of flow forced shell and tube heat exchangers. Frequency response data for four heat exchangers with different baffle geometry were obtained. A second order critically damped transfer function gave an adequate description of the dynamic behaviour. The apparent natural frequency is a function of the shell‐side and tube‐side flow rates and fluid properties, as conveniently expressed by the overall heat transfer coefficient; and of the size and shape of the baffle compartments, as expressed by the ratio of shell diameter to baffle spac

ISSN:0008-4034    

DOI:10.1002/cjce.5450470405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractA system of catalyst classification is proposed. Nine classes of catalyst aging behavior are suggested based on the instantaneous and cumulative effects predicted by the time‐on‐stream theory of catalyst decay

ISSN:0008-4034    

DOI:10.1002/cjce.5450470406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractThe concentration of solute in a film flowing down an inclined plane has been obtained by solving the complete diffusion equation, including the diffusion effect in the direction of flow. The formulation leads to the necessity of solving non‐orthogonal characteristic value problem, treatment of which is, however, quite straightforward.Though the motivation for the study was the diffusion of oxygen to plasma or blood films, solutions are presented for the complete range of fluid properties, due to the great significance of this mode of flow for wider application in chemical engineerin

ISSN:0008-4034    

DOI:10.1002/cjce.5450470407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractA numerical analysis has been made of laminar stratified flow of two immiscible Newtonian liquids in circular and certain non‐circular pipe configurations. Solutions are given far viscosity ratios of 10, 100, and 1000 and for various volumetric flow rate fractions. Five pipe configurations are studied. In each case volumetric flow rate factors and power reduction factors are computed. It is shown that the circular pipe is the best pipe configuration for the two‐phase flow having a viscosity ratio of about 10 or less. A flat bottomed pipe configuration is found to give higher volumetric flow rate factors as well as higher power reduction factors than the circular pipe when the viscosity ratio is about 100 or m

ISSN:0008-4034    

DOI:10.1002/cjce.5450470408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractMeasurements of the collapse rates of small bubbles injected into particulate gas fluidized beds show that the net transfer rate of gas from the bubbles to the continuous phase decreases as the background velocity is increased. The results indicate that the minimum stable bubble volume in a bed fluidized at a velocity equal to twice the minimum fluidizing velocity is 0.08 cc. Evidence of increase in the continuous phase voidage in the path followed by a bubble has been observed; this would explain the formation of stable bubble tracks.

ISSN:0008-4034    

DOI:10.1002/cjce.5450470409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY

摘要:

AbstractPeclet numbers describing axial dispersion in gas flow through packed beds of spheres were obtained using a two measurement point, pulse technique in a test section four inches inside diameter and 5.14 feet high. Three packing sizes were investigated, corresponding to tube to particle diameter ratios of 6.4, 17, and 66In the experiments the contribution of the velocity profile to axial spreading was reduced by using thermal conductivity detectors which responded to dispersion only in the central part of the bed cross‐section. In this region of a packed bed the velocity profile is relatively flat. The results point to a particle diameter effect which is more pronounced than has been previously reported. This is in accord with the diffusive mechanism of axial dispersion in a packed bed provided dispersion caused by the velocity profile does not affect the measured pulse response.In the absence of velocity profile effects, the spreading of residence times in void cells is caused primarily by the shedding of the decelerated boundary layers on the downstream side of the particles. At low velocities however, molecular diffusion predominates. Implicit in this discussion is the hypothesis that the uniformity of shape and size of packing particles has an important bearing on the manner in which the Peclet number approaches its limiting value as the gas velocity is increase

ISSN:0008-4034    

DOI:10.1002/cjce.5450470410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1969

数据来源: WILEY