摘要:

AbstractThe equilibria obtained during the crystallization of waxes has been studied theoretically and it has been found that the degree of separation between normal paraffins may be predicted, if it is assumed that the solid is an ideal solution. Results predicted from the theoretical equations have been compared with mass spectrometer analyses of recrystallized waxes and surprisingly close agreement has been found.It has also been shown that ketone solvents have essentially the same selectivity for recrystallizing waxes as n‐hexane. The reason for this is that the activity coefficients for various n‐paraffins in a ketone solution are nearly identical even though they are all much higher than in the hydrocarbon solution.The separation between normal paraffins in conventional single stage wax recrystallization is not very sharp. This may be improved by the use of a number of stages in a countercurrent cascade. Experimental results with such a cascade are in agreement with the theoretical predictions.The presence of non n‐paraffinic components in some waxes can cause the formation of eutectic mixtures. This affects the separation in a manner analogous to that of hetero‐azeotropes in some distillation processes.The crystallization of waxes from their, melts has also been studied both theoretically and experimentally. When mixtures of similar molecular weight n‐paraffins, such as n‐C21H44and n‐C23H48are cooled, a solid solution is formed. This is also found with mixtures of similar recrystallized waxes. On the other hand, mixtures of n‐paraffins of widely different molecular weight, such as n‐C20H42and n‐C32H66, or hydrocarbons of different structure, such as n‐paraffins and iso‐paraffins, form separate crystals and a eutectic. Similar results are found with mixtures of commercial waxes of widely different

ISSN:0008-4034    

DOI:10.1002/cjce.5450390202

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

年代:1961

数据来源: WILEY

摘要:

AbstractA graphical method for determining the process conditions which give the minimum volume of reactor at a given outlet conversion is described, and illustrated by application to a multistage fluidized bed reactor for the catalytic oxidation of sulphur dioxide.

ISSN:0008-4034    

DOI:10.1002/cjce.5450390203

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

年代:1961

数据来源: WILEY

摘要:

AbstractThe upward vertical flow of oil‐water mixtures has been investigated in a 37‐ft. length of cellulose acetate butyrate tubing of inside diameter 1.038‐in. Flow pattern, holdup and pressure drop data were obtained for water mixtures with 0.936, 20.1 and 150 centipoise oils at superficial water velocities ranging from 0.10 to 10.0 ft./sec.The oil‐water mixtures exhibited a behavior similar to that of air‐water mixtures studied previously. The flow patterns observed at constant superficial water velocity with increasing oil‐water ratio were: drops of oil in water, slugs of oil in water, froth, and drops of water in oil. Holdup of the phase forming the continuous medium was observed but to a much lesser extent than with the air‐water system. Curves of pressure drop versus oil‐water ratio exhibited a minimum, a maximum and a second minimum at low water velocities; a single minimum at intermediate water velocities; and a steady increase at superficial water velocities above about 5 ft./sec.A friction factor based upon the properties and the superficial velocity of the water is correlated with the superficial velocity of the oil and a Reynolds number based on the properties and superficial velocity of the water. This shows that the pressure drop due to friction and other irreversibilities is essentially independent of the viscosity of the oil except under conditions where the oil is the c

ISSN:0008-4034    

DOI:10.1002/cjce.5450390204

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

年代:1961

数据来源: WILEY

摘要:

AbstractRheological characteristics and thixotropic behavior of four clay minerals belonging to different types of morphology and lattice structure were investigated.Clay‐water samples were prepared at about their liquid limits and the testing was accomplished by unconfined compression applied at different rates of deformation.From the stress to strain rate relationships the yield value was determined as an intercept on the stress axis at zero rate of strain, and the slope gave the viscosity coefficient.Regain of strength or thixotropic character of the samples was evaluated in terms of the viscosity and yield values at various periods of aging.The influence of temperature on the aging process was studied using attapulgite at three temperatures, 21°C., 36°C., 51°C.The activation energy of the process of aging for attapulgite was calculated using both viscosity coefficients and ultimate yields. The values were within experimental uncertainty for the two sets of data and it was thereby concluded that changes of these parameters were due to a single reaction. The activation energy was found to be 9.4 kcal mole−1, which suggests a physical rather than a chemical

ISSN:0008-4034    

DOI:10.1002/cjce.5450390205

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

年代:1961

数据来源: WILEY

摘要:

AbstractSolution of the non‐linear differential equations of a continuous flow stirred‐tank reactor, with a first‐order reacting system, has been accomplished by the use of the analog computer. The three common modes of control have been programmed on the computer and, while controlling temperature or composition by means of the adjustment of cooling water flow rate, the regions of stability have been determined for various values of the controller constants. These results have been compared to those obtained by applying the root‐locus method to the linearized forms of the differential equations previously

ISSN:0008-4034    

DOI:10.1002/cjce.5450390206

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

年代:1961

数据来源: WILEY

ISSN:0008-4034    

DOI:10.1002/cjce.5450390207

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

年代:1961

数据来源: WILEY

摘要:

AbstractThe catalytic combustion of 1‐hexene present in diluent nitrogen in the concentrations of 1170 p.p.m. and 3000 p.p.m. by excess oxygen, has been studied in the presence of the CuO‐Al2O3(1:1) catalyst in the temperature range 242° to 424°C. and gas space velocity in the range 4000–16,000 hr.−1. The experimental data on the kinetics of the reaction were found to fit an empirical half‐order law with respect to the 1‐hexene concentration. The presence of water vapor in the reactants was found to have no effect on the efficiency of the catalyst at temperatures higher than 400°C. The above results were similar to those obtained for the catalytic oxidation of n‐hexane studied earlier.The possible use of the above copper oxide‐alumina catalyst for the simultaneous removal of hydrocarbons and carbon monoxide present in the auto exhaust gases has been tested, making use of a 1955 six‐cylinder Chevrolet engine run on leaded gasoline fuel. The hydrocarbon and carbon monoxide concentrations encountered in these studies varied in the range 170–16,000 p.p.m. and 1–7% respectively. It was found that the minimum initial temperature of the catalyst bed required for the complete removal of both hydrocarbons and carbon monoxide, simultaneously, was 226°C. under no load condition, 342°C. under an engine load of 2.5 h.p., 400°C. under an engine load of 5.1 h.p. or higher, and 236°C. under deceleration conditions. The catalyst showed no deterioration in performance even after 100 hours of continuous service in conjunction with

ISSN:0008-4034    

DOI:10.1002/cjce.5450390208

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

年代:1961

数据来源: WILEY

摘要:

AbstractThe process of spherical agglomeration provides a method for making rapid and efficient separations of solids from liquid suspensions. Because preferential wetting of the solid surface by a second liquid, which acts as a bridging agent between the particles, is a basic requirement of the operation, a novel method for the separation of multi‐component solids becomes available. The procedure is also useful in the breaking of emulsions through the addition of a finely divided solid, the surface of which is repellent to the continuous phase and wetted by the emulsified phase. The process operates equally well in aqueous or in organic media. A number of illustrative examples are give

ISSN:0008-4034    

DOI:10.1002/cjce.5450390209

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

年代:1961

数据来源: WILEY

ISSN:0008-4034    

DOI:10.1002/cjce.5450390201

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

年代:1961

数据来源: WILEY