Showing papers in "Industrial & Engineering Chemistry Fundamentals in 1976"

A New Two-Constant Equation of State

Abstract: The development of a new two-constant equation of state in which the attractive pressure term of the semiempirical van der Waals equation has been modified is outlined. Examples of the use of the equation for predicting the vapor pressure and volumetric behavior of singie-component systems, and the phase behavior and volumetric behavior of binary, ternary, and multicomponent systems are given. The proposed equation combines simplicity and accuracy. It performs as well as or better than the Soave-Redlich-Kwong equation in all cases tested and shows its greatest advantages in the prediction of liquid phase densities.

The Measurement and Prediction of Hydrate Formation in Liquid Hydrocarbon-Water Systems

Abstract: The University of Alberta obtained equilibrium three-phase water liquid-hydrocarbon liquid-solid hydrate data for the methane--isobutane--water system and for six multicomponent mixtures containing isobutane, at pressures up to 2200 psia and temperatures above 32/sup 0/F. The theory of J.H. van der Waals and J.C. Platteeuw for predicting hydrate forming conditions in gases was modified to make it applicable to gas and liquid mixtures. The method was also applied to the prediction of the four-phase equilibrium locus.

A Low-Reynolds-Number Analysis of Gas Bubbles in Fluidized Beds

Abstract: The gas and solids flow through and around bubbles in fluidized beds is treated under the assumption that such bubbles rise at low Reynolds numbers. This enables the calculation of bubble shape. The bubbles are found to be slightly elongated and similar to a gas slug in a tube, not representative of the spherical-cap bubbles which normally appear in fluidized beds. A detailed examination of the transition from bubble to suspension phase will be needed for any precise description of bubbles which rise at intermediate Reynolds numbers.

Vapor-Liquid Equilibria by the Pseudocritical Method

Abstract: The New Jersey Institute of Technology has extended the pseudocritical method of B.I.Lee and M.G. Kesler to the calculation of component fugacity coefficients and vapor-liquid equilibria. The Lee-Kesler mixing rules have been modified by the introduction of binary interaction constants, which are evaluated from experimental pseudocritical constants. The critical compressibility factor is introduced as a correlating fourth parameter. The resulting component fugacity coefficients agree with experimental values and with experimentally determined vapor-liquid equilibrium ratios. The proposed method may be applied to systems with any number of components. It is well-adapted to computer programming, being based on the modified BWR equation of Lee and Kesler. Components presented are methane, propane, n-butane, and carbon dioxide.

Rapid Heating-to-Ignition of High Explosives. I. Friction Heating

Abstract: A friction ignition model was developed that predicts the thermal decomposition of condensed phase explosive when impacted at an oblique angle on rigid target surfaces. The model was verified by the experimental initiation behavior of pressed hemispherical billets of PBX 9404 subjected to an oblique impact on targets with widely varying thermal conductivities. The explosive was impacted on targets of fused quartz, aluminum oxide, and gold with similar surface characteristics. The experimentally determined estimates of the drop heights required to produce an explosive event ranged over two orders of magnitude, with the high conductivity gold target and the low conductivity quartz target being, respectively, the least and most sensitive. These results were satisfactorily explained with the thermal ignition model by computer simulation of the mechanical and thermal events occurring during the oblique impact leading to ignition of the charge. No attempt was made to calculate the buildup from ignition to detonation.

Mechanisms of Gas Desorption from Aqueous Solution

Abstract: The desorption of CO from supersaturated water solution has been extensively studied using a string-of-spheres apparatus. Dissolved gas supersaturation, liquid flow rate, gas phase composition, and the nature of the solid spherical surfaces were varied. When the ratio of the partial pressure of dissolved gas to total system pressure was below unity, mass transfer was purely diffusional whereas for values of this ratio greater than unity, desorption was accompanied by the rapid generation of gas bubbles. Spheres which were artificially roughened gave higher bubbling desorption rates than smooth polished spheres. No such differences were detected in the absence of bubbling. Mass transfer coefficients were found to be higher for absorption than for non-bubbling desorption.