摘要:

AbstractHydrocracking and gasification are processes which decrease the molecular weight of fossil fuel feedstocks. The conversion of natural gas to hydrocarbon liquids involves an increase in molecular weight. The reaction sites of the catalysts used to accomplish these molecular weight changes are described. Since changes in the valence electrons are responsible for the cleavage and formation of the chemical bonds in hydrocarbon molecules, the solid catalyst has also been described in terms of its electronic characteristics. The description of a catalyst in these terms is able to provide a qualitative explanation for its function in molecular weight change reactions. Changes in conversion caused by variations in catalyst composition are also explained.

ISSN:0008-4034    

DOI:10.1002/cjce.5450610201

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

年代:1983

数据来源: WILEY

摘要:

AbstractA light‐scatter technique, marker nephelometry, was used to obtain air‐in‐air mixing data on the system resulting from the injection, at right angles through a port in the wall, of a round subsonic jet into a fully developed turbulent pipe flow. Though the pipe Reynolds number was also varied, the important input variables were the port to pipe mean speed ratio of the input streams (2.5–12.5), and the port to pipe diameter ratio (0.020–0.058). Jet trajectories were measured and the associated mixing field was characterized in terms of both the jet source fluid mean concentration and concentration fluctuations. The process was also studied as to concentration fluctuation spectral density, integral scale, and inte

ISSN:0008-4034    

DOI:10.1002/cjce.5450610202

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe hydrodynamics and the pulse properties in the pulse flow regime of gas‐liquid downflow through a packed column were studied using 6 mm Raschig rings and 3 mm spheres as packings. The pulse flow regime is considered to be gas‐continuous flow outside the pulses and more like dispersed bubble flow inside the pulses and the pressure drop is viewed as being contributed to by the gas continuous part outside the pulses and by the pulses themselves. Correlations for the total pressure drop, the pressure drop across the pulse and for the pulse velocity are obtained. The experimental data of the average holdup, the pulse holdup, the base holdup and the transition from gas continuous to pulse flow regime are compared with the literature val

ISSN:0008-4034    

DOI:10.1002/cjce.5450610203

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe paper covers an experimental and theoretical investigation of the dispersed phase holdup and drop size distribution for gas‐liquid and liquid‐liquid counter‐current flow in reciprocating plate columns provided with plates having small hole size and free area. The response of the reciprocating plate column is similar to that of liquid‐pulsed columns exhibiting mixer‐settler and emulsion regions. The dispersed phase holdup depends on the dispersed phase flow rate, the vibrating speed of the plate stack, the plate geometry and the number of plates: it was found to be minimum at the transition between the mixer‐settler and emulsion regions.The dispersed phase holdup is modeled incorporating apparent interstitial liquid velocity and the slip velocity to account for the non‐descriptive flow pattern between the phases.The drop size distribution is satisfactorily represented on a Rosin–Rammler Chart. Sauter mean diameter, calculated from the distributions, indicated an advantage in the drop size‐power consumption relation when plates having small hole size and free area are used.Equipment used for fluid‐fluid contacting is often broadly classified as either stagewise or differential contactors. The classification is further sub‐divided as gravity, mechanically‐agitated and pulse‐agitated, depending on the method adopted for interdispersing the phases. Pulse‐agitation involves the use of either reciprocating perforated plates moving vertically up and down the column, or pulsing a phase hydraulically keeping the internal structure of the column stationary.The literature on reciprocating plate columns (RPC) primarily is concerned with the study of liquid‐liquid systems using perforated plates having large hole size and free area. This paper presents the dispersed phase holdup and drop size distributions for gas‐liquid and liquid‐liquid systems in reciprocating plate columns with small perforation dia

ISSN:0008-4034    

DOI:10.1002/cjce.5450610204

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

年代:1983

数据来源: WILEY

摘要:

AbstractA theory is proposed for correlating the mist‐annular transition during condensation based on a balance between destructive and stabilizing forces acting on the liquid film. The resulting correlation is shown to be capable of good agreement with a data base corresponding to a wide range of fluid properties and tube diameters. A fair deal of generality is demonstrated by testing the correlation outside the range from which it was develope

ISSN:0008-4034    

DOI:10.1002/cjce.5450610205

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

年代:1983

数据来源: WILEY

摘要:

AbstractA model, based on a Langmuir‐Hinshelwood type mechanism, for the oxidation of carbon monoxide on a platinum catalyst is presented. This model is used to explain resonant behavior which has been observed during forced feed composition cycling of catalytic reactors. This model further predicts that catalytic reactions can display pathological behavior under certain conditions of feed cycling in agreement with experimental observation

ISSN:0008-4034    

DOI:10.1002/cjce.5450610206

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe design and operation of a small‐scale semi‐continuous reactor to convert aspen wood meal into an oil product is described. Modifications that reduce erosion/corrosion are also presented.Short residence times and relatively low operating pressures have been achieved for the reaction of aspen with CO and H2O in the presence of Na2CO3. Conversions, char formation, and the effect of sodium carbonate concentration on oil product are repor

ISSN:0008-4034    

DOI:10.1002/cjce.5450610207

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe conversion of carbon monoxide to carbon dioxide was measured in a recyle reactor automatically controlled by a computer. Two Pt/SiO2catalysts of different dispersion were employed. Isothermal experiments (in which the carbon monoxide inlet concentration was varied) and temperature‐programmed experiments (in which the temperature was varied) yielded multiple steady states and complete hystereses.The rate data were controlled well by three LHHW kinetic models. However only two of them predicted well the transitions from low to high conversio

ISSN:0008-4034    

DOI:10.1002/cjce.5450610208

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

年代:1983

数据来源: WILEY

摘要:

AbstractSteady state kinetics of the oxidation reaction have been determined with the help of a gradientless semi‐differential, fixed‐bed reactor. The Mars and van Krevelen phenomenological model satisfactorily correlates the experimental data but a modification of the Langmuir‐Hinshelwood model taking into account partial coverage of the catalyst surface with reaction intermediates is preferred.Transient kinetics have been studied with a new automated periodic‐pulse reactor, directly connected to a gas chromatograph. The response of a catalyst (essentially V2O5–MoO3) to reduction and oxidation has been investigated. The rate of bulk (lattice) oxygen utilization as well as the degree of carbon coverage are estimated by this technique. Selectivity is dependent on the oxidation state of the catalyst: high partial pressure of either benzene or oxyen and high temperatures are detrimental to se

ISSN:0008-4034    

DOI:10.1002/cjce.5450610209

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

年代:1983

数据来源: WILEY

摘要:

AbstractAs part of a study to evaluate the performance of a “dry” catalytic method of removing low concentrations of H2S from cupola gas, the rate of oxidation of low concentrations of H2S by air at room temperature has been studied using a fixed activated carbon bed. Previous studies have presented somewhat contradictory results.It was found that the rate decreased with time, consistent with a rapidly fouling catalyst, and finally attained a steady state value. A mechanism is presented which is in agreement with the results.The oxidation rate was also found to increase drastically by increasing the air humidity, contrary to the published results of some other work

ISSN:0008-4034    

DOI:10.1002/cjce.5450610210

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

年代:1983

数据来源: WILEY