ISSN:0001-1541    

DOI:10.1002/aic.690140602

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690140606

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractThe most active zeolite hydroisomerization catalyst found during the course of a series of screening experiments was palladium impregnated hydrogen mordenite. The high activity of hydrogen mordenite catalyst was also reported by research workers of the Shell Oil Company. (11) Typical conditions used in this study were 550°F., 450 lb./sq.in. gauge, 8 g. ofn‐pentane fed /h./g. of catalyst, and a hydrogen/pentane molar ratio of 3.4.Process variable studies have shown that neither gas toparticle mass transfer, intraparticle (macro‐pore) diffusion, nor the chemical reactions at the palladium sites are rate limiting. The data can be correlated by a mathematical model based on the assumptions that a first‐order, reversible isomerization reaction on the mordenite acidic sites is rate‐controlling, and the apparent rate constant is an Arrhenius function of thetemperature of the system.The pressure dependency of the reaction rate constant is consistent with a dual‐site mechanism and Langmuir adsorption

ISSN:0001-1541    

DOI:10.1002/aic.690140607

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractLongitudinal liquid mixing in fluidized and fixed beds was studied using sinusoidal and pulse response techniques. The tracer used was light emissive fluorescein dye. A systematical study of liquid phase dispersion by varying particle size, fluid velocity, fraction voids, and particle density was conducted. A generalized correlation applicable to both fixed bed and fluidized bed was obtained. The application of the correlation in predicting the effect of the dispersion on reactor performance was discussed.

ISSN:0001-1541    

DOI:10.1002/aic.690140608

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractA study was made to evaluate pulses as a forcing function on a 24‐plate distillation column. Pulses of two shapes, rectangular and displaced cosines, and of different widths were used as inputs to the reflux return line from the condenser to the column. The effect of the disturbance was a change in the liquid return rate which correspond to the shape and size of the pulse. The output responses of the system were temperatures measured at different times and at different plates in the column.Bode diagrams were plotted from the experimentally determined data. From these plots, it was determined that the system could be approximated by linear first‐order equatons. The time constants for the linear system were determined both by direct sinusoidal forcing and by pulse forcing. Pulse data were considered acceptable when the values of the time constant and the phase angle determined by the pulse compared favorably with those determined by steady state sinusoidal forc

ISSN:0001-1541    

DOI:10.1002/aic.690140609

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractClosed analytic Stokes flow solutions for general shapes are quite improbable, but semianalytic numerical procedures allow flow calculations for a variety of shapes. The change in drag with change in shape from a sphere, here expressed in terms of a form factor, is discussed and compared to empirical shape factors developed from sedimentation experiments.

ISSN:0001-1541    

DOI:10.1002/aic.690140610

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractA digital computer solution of the equations of fluid motion predicts the pressures in an expansible tube through which liquid is flowing.To obtain a stable solution, it is necessary to assume that the rate of change of area with time is proportional to the rate of change of velocity with time. This assumption is shown to be a reasonable one.Calculations for the rate of travel of pressure pulses are in good agreement with experimental results.

ISSN:0001-1541    

DOI:10.1002/aic.690140611

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractThis paper discusses the effects of imperfect mixing on the stability of autorefrigerated chemical reactors. Mixing is shown to strongly influence stability in these evaporatively‐cooled systems. A modified van Heerdensteady state stability analysis is presented. Computer simulation of a typical system illustrates the occurrence ofrunaways and local hot spots. Both continuous stirred tank reactors and batch reactors are considere

ISSN:0001-1541    

DOI:10.1002/aic.690140612

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractA new method, based upon chromatography, was used to measure surface diffusion coefficients for ethane, propane, andn‐butane on silica gel. The diffusivities correspond to very low surface coverages (fraction of a monolayer of the order of 10−4) and hence should represent limiting values. A survey of available surface diffusion information, all at higher coverages, indicated that the results reported here are at the lower end of the range of diffusivities. The activation energy and heat of adsorption, for example, forn‐butane, were 4.4 and −7.8 k cal./mole, respectively.Surface diffusion was a significant fraction of the total intraparticle mass transport, in part because in the small pores in silica gel gas phase diffusion was solely by the Knudsen mechanism. For propane, surface migration was 73% of the total transport at 50°C. and 61.5%

ISSN:0001-1541    

DOI:10.1002/aic.690140613

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY

摘要:

AbstractThe Martinelli model for pressure drop in flowing two‐phase systems has been examined in detail for para‐hydrogen from 1 atm. to its critical pressure. Amethod for obtaining the Martinelli Φ term, two phase friction factor, at intermediate pressures is presented. Φ2can be expressed as a function of pressure and quality. The Martinelli β term, ratio of actualvapor or gas area to an idealized cylindrical area, is found to vary greatly and to indicate first an increase in gas‐liquid interface to gas volume ratio and then a decrease with increasing pressure. Some experimental data are examined in light of this dev

ISSN:0001-1541    

DOI:10.1002/aic.690140614

出版商:American Institute of Chemical Engineers    

年代:1968

数据来源: WILEY