Showing papers in "Chemical Engineering Science in 1994"

TL;DR: In this article, a model based on the assumption of plug flow of supercritical solvent through a fixed bed of milled material was developed for both extraction periods and a new model with analytical solution was developed on the basis of these models.

TL;DR: In this paper, the status of research on the dynamics of electrochemical reactions is reviewed, including the electrodissolution of metals, cathodic deposition, and electrocatalytic reactions.

TL;DR: In this paper, the authors investigated the effect of milling of grape seeds, solvent flow rate and flow direction on the course of extraction and found that the smaller the amount of milled seeds in the extractor and the slower the upward flow, the more pronounced was this effect.

TL;DR: In this paper, a simplified model is proposed based on the assumption that the transport of gas molecules from the gas phase to the liquid water phase is the rate-determining step in the overall hydrate formation process.

TL;DR: In this article, a flat bubble column with rectangular cross-section and essentially two-dimensional flow structure was studied in terms of gas-liquid bubble flow and the experimental results were compared with numerical simulations based upon the dynamic laminar 2D two-phase Euler-Euler model presented in Part I.

TL;DR: In this paper, a two-dimensional finite-element simulator was used to examine previously reported studies of propane and carbon monoxide combustion in excess oxygen, and the results from the simulations are much higher than results which have been reported in the literature for experimental work.

TL;DR: In this paper, the metastable region for hydrate nucleation is discussed and the driving force for hydrates is defined, and the induction period data for the various hyddrates from a total of 93 hydrate formation runs were modelled as a function of the nucleation driving force.

TL;DR: In this article, the state of the art of the modelling of gas-liquid flow in bubble columns and loop reactors is reviewed, and the results obtained with dynamic multidimensional two-fluid models are compared with respective steady state simulations.

TL;DR: In this paper, three-dimensional flow structures of dilute suspensions in the freeboard of a bubbling fluidized bed as well as in a circulating fluidised bed of 200 mm internal diameter, roughly a (125-scale model of a commercial boiler, were observed by the laser sheet technique.

TL;DR: In this article, experimental results for isothermal Newtonian flow through metallic foams are analyzed in comparison with a theoretical model and the results interpreted, in both the Darcy and non-Darcy regimes the results show promise for the accurate theoretical prediction of fluid dynamic phenomena in foamlike porous materials of very high porosity.

TL;DR: In this paper, the combined shift and carbonation reactions were studied in a laboratory-scale fixed-bed reactor containing dolomite sorbent precursor, and the effect of shift-carbonation temperature and pressure, synthesis gas composition, space velocity, and composition and properties of the sorbent were studied.

TL;DR: In this article, the authors present a general methodology for the design of distributed effluent treatment systems, which can, in the appropriate circumstances, lead to significantly lower capital and operating costs when compared with centralised treatment.

TL;DR: In this paper, a vapor phase biological reactor known as a biofilter was used to remove toluene vapor from airstreams, where a mixture of peal and perlite particles was packed with a mixed microbial population (consortium) and formed a biolayer.

TL;DR: In this article, a two-dimensional computational fluid dynamics study of the two-phase gas-liquid flow in bubble columns is presented, where the flow is modelled by a Navier-Stokes system of equations in an Eulerian representation, whereas the motion of the gas is modeled on a smaller scale by tracking individual bubbles or bubble clusters through the liquid in a Lagrangian way.

TL;DR: In this paper, the problem of reactor configuration selection is analyzed at three strategy levels, i.e., catalyst design, energy injection and dispersion strategies, and contacting flow pattern.

TL;DR: In this article, the H-K formulation is modified by including the nonlinearity of the isotherm, which results in sharpening of the pore size distribution and shifting of its peak position to a smaller size.

TL;DR: In this article, the influence of pressure on the gas hold-up in a bubble column is determined for a sodium sulphite solution in combination with the volumetric mass transfer coefficient.

TL;DR: In this article, the authors review the experimental evidence, especially the anomalous experimental observations of interest to engineers, concerned with enhancement (which is sometimes rather dramatic) in heat, mass and momentum transfer during the flow of such sliding fluids.

TL;DR: In this paper, the Generalized Mixing Model (GMM) is used to model mixing in semi-batch reactors of different sizes studied by a novel parallel-competing test reaction and mixing of a stream of initiator in a recycle tubular reactor packed with static mixers for the polymerization of styrene.

TL;DR: In this article, a modified version of the Wertheim perturbation theory for the hard-sphere chain fluid by incorporating structural information for the diatomic fluid is presented.

TL;DR: In this article, the influence of process parameters like the cone rotational speed (6-15 Hz), the reactor volume (3-200 l), the wood-dust feed rate (1-3.5 g s−1) and the reactor temperature (550−700°C) on the product composition was investigated.

TL;DR: In this paper, a model was developed to predict the rate of iodine formation for KI solutions of various concentrations under different gas atmospheres using the Rayleigh-Plesset bubble dynamics equation, where the bubble is assumed to behave isothermally during its growth phase and a part of the collapse phase.

TL;DR: A comprehensive review of the application of NMR spectroscopy in the field of chemical engineering can be found in this article, where the authors identify three broad categories of magnetic resonance measurements, namely spectrograms, diffusion measurements, and imaging.

TL;DR: In this paper, the Gibbs-Duhem integration method is extended to mixtures, based on the semigrand and osmotic forms of a generalized Clapeyron equation.

TL;DR: Choi and Ray as discussed by the authors examined the influence of bubble size and superficial velocity on reactor operation and showed that bubble size critically influences the rate of heat and mass transfer within the bed, and when the bubbles are as small as those predicted by the maximum stable bubble size correlations, there is little or no resistance to the transfer of monomer and heat between the phases.

TL;DR: In this paper, the effect of high pressure on pressure drop and liquid holdup in the trickle flow regime was investigated using a phenomenological analysis based on annular two-phase flow in a slit.

TL;DR: In this article, a continuous potential interaction for frictional granular flows is introduced to ensure the stability of contact mechanical force algorithms over much larger time steps than were hitherto possible, by allowing softer interactions which vary on the same scale as the nominal particle size rather than the micro-contact scale used in the majority of previous literature.

TL;DR: In this article, the shape of the bridge is approximated as a toroid and the bridge half-filling angle is taken as independent of surface separation, with a value corresponding to that at the rupture distance.

TL;DR: In this article, a review of recent developments in the field of chemical reaction engineering is presented, focusing on somewhat more classical aspects of mixing in the content of Chemical Reaction Engineering and providing additional fluid mechanical perspective.

TL;DR: In this paper, the authors studied the kinetics of nitrate reduction with hydrogen in a metallic monolith reactor, where the catalytically active material was Cu-doped Pd supported on Al 2 O 3.