ISSN:0001-1541    

DOI:10.1002/aic.690090602

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690090604

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690090605

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

摘要:

AbstractA theoretical and experimental investigation of the effects of horizontal barriers on the separation of binary mixtures attained in thermogravitational thermal diffusion columns was undertaken in an attempt to further the understanding of these effects. The presence of horizontal barriers serves to reduce the internal convective flow and to divide tht column into a number of smaller columns with interconnecting end feeds. Equations developed from such a model serve to predict the effect of the number of barriers, temperature difference, barrier diameter, and other parameters on the steady state and transient behavior of a batch column and on the manner in which bulk flow through the column influences the steady state separation in continuous‐flow columns.Data were taken in both batch and continuous columns to test the theory. Parameters varied experimentally (with an ethanol‐water system) were number of barriers, (N = 0, 2, 4, 8, 16, 50), temperature difference, and diameter of the cylindrical barriers. It was found that the theoretical developments were entirely adequate to explain the observed influence of number of barriers for both types of column operation. The slight dependence of steady state batch separation on temperature difference that was observed is consistent with data of other investigations, and the independence of this type of separation on barrier diameter is in agreement with theoretical predictions. The theoretical predictions with respect to changes in temperature difference and a semitheoretical analysis of the effect of barrier diameter making use of isothermal hydrodynamic determinations proved satisfactory in predicting the influence of changes in these two parameters on both the transient batch and steady state continuous‐flow column oper

ISSN:0001-1541    

DOI:10.1002/aic.690090606

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

ISSN:0001-1541    

DOI:10.1002/aic.690090607

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

摘要:

AbstractA representative paraffin hydrocarbon in the gas oil range,n‐hexadecane, has been irradiated in the Industrial Reactor Laboratories' 5 mw. nuclear research reactor. In the vapor phase radiation‐induced cracking proceeded efficiently, and G values for radiation conversion ofn‐hexadecane were 200 to 1,200 at temperatures near 750°F. Total conversions ofn‐hexadecane were less than 3 wt. % and were due only in part to the radiation effect. The distributions of products which were obtained were similar to those which result from thermal cracking ofn‐hexadecane. There were however significant increases in the yields of hydroger., reductions in the yields of very light hydrocarbons and small yields of high molecular weight products. At temperatures above 850°F. extensive thermal cracking obscured the effects of radiation.In liquid phase radiation‐induced cracking at 750°F. conversions ofn‐hexadecane up to 15 wt. % have been obtained at liquid spaces velocities near 4 v./hr./v. In many exposures nearly one‐half of this conversion was attributed to the direct utilization of radiation. The corresponding G values were 30 to 60. The products obtained have been accounted for by adding together the products which would be expected from a radiation‐induced reaction producing primarily dimer, from radiation‐initiated chain propagated cracking, and thermally initiated chain cracking. The product distribution from these reactions can be changed by variation of the cracking temperature

ISSN:0001-1541    

DOI:10.1002/aic.690090608

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

摘要:

AbstractNo Abstrect.

ISSN:0001-1541    

DOI:10.1002/aic.690090609

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

摘要:

AbstractTheoretical and experimental work is described which leads to a novel hypothesis for explaining the selectivity in heterogeneous vapor phase hydrocarbon oxidation catalysis. Two essential postulates of the hypothesis are:The oxygen atoms must be distributed on the surface of a selective oxidation catalyst in an arrangement which provides for limitation of the number of active oxygen atoms in various isolated groups.The metal‐oxygen bond energy of the active oxygen atoms, at the conditions of reaction, must be in a range where rapid removal (hydrocarbon oxidation) and addition (regeneration by oxygen) is assured.Monte Carlo methods are used to illustrate the distribution of isolated sites on catalytic surfaces under the dynamic conditions of hydrocarbon oxidation reactions. Differences in catalyst and process requirements between oxidation processes operating in an overall oxidizing or reducing atmosphere are discusse

ISSN:0001-1541    

DOI:10.1002/aic.690090610

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

摘要:

AbstractRates of carbon dioxide absorption by 0.01, 0.05, and 0.1 molar sodium hydroxide solutions were measured at 25°C. for exposure times from 1.4 to 21.6 milliseconds with a laminar‐jet technique. Absorption rates were calculated with a model based on one‐dimensional diffusion occurring simultaneously with two consecutive irreversible chemical reactions. The resulting partial differential equations were solved with an IBM‐709 computer. The calculated absorption rates agreed within 5% of the experimental

ISSN:0001-1541    

DOI:10.1002/aic.690090611

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY

摘要:

AbstractEntrance‐region studies, based on static‐pressure measurements, were carried out with water flowing in annuli and a circular tube fitted with interchangeable square or rounded entrance sections. The tests covered the Reynolds number range from 16,000 to 70,000. For the annuli, the length of duct required to approach to within 5% of the fully developed pressure gradient was about 20 to 25 hydraulic diameters. This is in general accord with entrance length results for circular tubes and parallel‐plate channels but differs from prior results for the annulus which had indicated entrance lengths larger by a factor of ten. The results for the sharp entrance showed a definite effect of separation and were characterized by high loss coefficients. For the rounded entrance, the initial part of the flow development was laminar; the entrance‐region pressure drop did not substantially exceed (and in one case was less than) the corresponding fully developed pressure drop. Also for the rounded entrance, flow stability was improved and a monotonically decreasing pressure gradient obtained when a turbulent boundary layer was induced by means of a trip. Fully developed friction factors were calculated and compared with

ISSN:0001-1541    

DOI:10.1002/aic.690090612

出版商:American Institute of Chemical Engineers    

年代:1963

数据来源: WILEY