Showing papers in "Chemical Engineering Science in 1992"

TL;DR: The properties of single-component diffusion of hydrocarbons in zeolites, especially its dependence on temperature and concentration, are studied theoretically by modeling the molecule-zeolite interactions and the molecules-molecule interactions as discussed by the authors.

TL;DR: Combustion synthesis offers many potential advantages over conventional techniques of synthesis, including relatively simple equipment, shorter processing times, lower energy requirements, higher product purities, and the possibility to synthesize metastable phases as mentioned in this paper.

TL;DR: In this paper, Monte Carlo calculations were performed to simulate the adsorption of natural gas on activated carbon and showed that the maximum delivered energy density of ANG is 0.25 for monolithic carbon and 0.17 for pelletized carbon, compared to 0.29 for CNG and 1.0 for gasoline.

TL;DR: Various theorems have been derived from the axiom system to ensure that this approach is mathematically rigorous, thereby rendering it possible to develop efficient process synthesis methods on the basis of a rigorous mathematical foundation.

TL;DR: In this article, a first-principles model for gas-fluidized bed based on the so-called "twofluid model" (TFM) has been developed, where both phases are considered to be continuous and fully interpenetrating.

TL;DR: In this paper, a generalized severity factor was proposed to account for the acid catalyst effect on the extent of reaction in the case of biomass fractionation leading to hemicellulose solubilization.

TL;DR: This review of bacterial and fungal models is preceded by a discussion of a general framework for the study of microbial kinetics and the use of a two-dimensional discretization of the kinetic model wherein both the individual cell and the cell mass is structured is shown to be helpful in dealing with comlex fermentation systems.

TL;DR: In this article, a phenomenological, pore-scale, hydrodynamic model is developed for representation of the uniform, two-phase, gas-liquid cocurrent flow in the low interaction regime in trickle bed reactors.

TL;DR: A key prediction from the analysis is that the flow velocity through affinity membranes may be limited not by pressure drop, but rather by association kinetics between soluble protein and immobilized ligand.

TL;DR: Theoretical and phenomenological aspects of trickle-bed reactors as reported in a wide number of papers of the last 35 years have been reviewed in this article, where several engineering topics have been focused by trying a critical interpretation of the attained results.

TL;DR: In this article, the absorption of CO2 from air into aqueous NaOH, monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP) solutions was reported.

TL;DR: In this paper, three approaches to nonlinear state estimation are evaluated for application to semi-batch polymerization problems, and the reiterative extended Kalman filter approach is shown to be the best suited for semibatch polymers.

TL;DR: The influence of the properties of molecule-zeolite systems on the diffusional and equilibrium behavior is experimentally investigated in this paper, where 16 hydrocarbons, including paraffins, two aromatics and a naphthene, were studied in ZSM-5.

TL;DR: In this paper, the dilution rate and feed substrate concentration are considered as manipulated inputs in single-input/single-output strategies for productivity control in continuous fermenters and compared theoretically and via simulation.

TL;DR: In this article, a particle image velocimetry (PIV) system is developed to measure local flow properties of a three-dimensional gas-liquid-solid fluidized bed, including instantaneous velocity distribution of different phases, velocity fluctuations, accelerations, gas and solids holdups, bubble sizes and their distributions.

TL;DR: Liquid—liquid extraction by reverse micelles of ionic surfactants in organic solvents is well suitable for separation and purification of extracellular enzymes from complex fermentation media, as demonstrated with α-amylase from Bacillus licheniformis.

TL;DR: A fixed bed composed of about 100 stacked microporous membranes is investigated for protein chromatography and a mathematical model and experimental verification indicate the condition under which nonlinear, kinetic and dispersive effects will occur.

TL;DR: Model-predictive control (MPC) as mentioned in this paper is a scheme in which an open-loop performance objective is optimized over a finite moving time horizon, and is shown to provide performance superior to conventional feedback control for non-minimum phase systems or systems with input constraints when future set points are known.

TL;DR: In this article, a liquid phase oxidation of phenol, chlorophenol, and nitrophenol by oxygen to carbon dioxide over a catalyst comprising CuO,ZnO, and λ-alumina in a slurry system undergoes heterogeneous -homogeneous free radical mechanism and behaves as an autocatalytic reaction system.

TL;DR: In this article, the reaction of CO2 with various alkanolamines (MEA, DGA, DIPA, DEA, MMEA) in aqueous solutions has been studied as a function of temperature.

TL;DR: In this article, the gas-liquid dispersion in a 1.0 m diameter stirred vessel has been explored on a quasi-point grid using an automated capillary suction probe which was designed for bubble-size measurement in pilot-scale contactors.

TL;DR: In this paper, a percolation-based analysis method was proposed for the determination of the connectivity of porous solids from nitrogen sorption measurements, and the results of the analysis were used to predict effective diffusivities, using effective medium theory.

TL;DR: In this paper, the effect of ligand concentration on both equilibrium and fixed-bed adsorption has been studied for three model proteins on dye-ligand adsorbents, and it was found that binding capacity was approximately proportional to immobilized dye concentration.

TL;DR: In this paper, an overview of the absorption models that are available for the calculation of the mass transfer rates in gas-liquid systems with (complex) reversible reactions is given, and conclusions on the applicability and restrictions are presented.

TL;DR: In this article, the authors present an overview of control applications that use state estimators based on calorimetric principles for the control of stirred tank ReReactor (STR).

TL;DR: In this article, a nonlinear model-predictive control method is developed and applied to a semibatch polymerization reactor using an explicit nonlinear process model and the basic elements of the classical dynamic matrix control (DMC).

TL;DR: In this paper, the authors extended pinch analysis for low-temperature process design to yield shaftwork targets directly from basic process data, by passing the design of both the heat exchanger network and the refrigeration system.

TL;DR: In this article, the deprotonation kinetics of the DEA-CO2 and the DIPA-CO 2 zwitterions have been studied in aqueous blends of amines at 298 K.

TL;DR: In this paper, an experimental investigation of the cake filtration behavior of 125-180 μm polyethylene particles, suspended in a neutrally buoyant Newtonian fluid, has been carried out.

TL;DR: In this paper, the authors developed a model to predict product distributions from fast diazo-coupling reactions which had been measured at two scales, two feed points, three concentration levels and various stirrer speeds.