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  • 1985-1989  (3,542)
  • 1980-1984  (2,596)
  • 1975-1979  (1,916)
  • Chemical Engineering  (8,054)
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  • 101
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1403-1404 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 102
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1409-1427 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Supercritical fluids (SCF's) are powerful solvents with many unique properties. They have great potential for many extraction processes, but reliable and versatile mathematical models of the phase equilibrium thermodynamics are needed for their use in process design and economic feasibility studies. This paper reviews existing experimental data and analytical methods and attempts to delineate their strengths and limitations. Also discussed are new data needs and possible new directions for a better fundamental understanding of the molecular processes in SCF solutions.
    Additional Material: 13 Ill.
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  • 103
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1457-1464 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Parameterization with respect to the aqueous reflux ratio has been carried out for the steady-state analysis of a tower to dehydrate secbutanol using disecondary butyl ether as the entrainer. With an equilibrium-stage model, singularities are observed as the second liquid phase is introduced on the trays and regions of steady-state multiplicity are demonstrated. Furthermore, a critical aqueous reflux ratio, in the vicinity of which two liquid phases are introduced on most of the trays, varies only slightly with the number of trays in the tower. The model predicts that the product purities and recoveries remain high using one-third of the trays in the industrial SBA-II tower. Bifurcation analysis for a single stage does not explain these observations, and the effect of recycle is suspected.
    Additional Material: 14 Ill.
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  • 104
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1487-1496 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This work presents a phenomenological correction to improve a classical equation of state for representing phase equilibria and densities in the vapor-liquid critical region. This correction consists of two steps. The first step is a volume translation which locates the correct critical point; this volume translation also improves density predictions for pure fluids and mixtures. The second step provides a near-critical contribution to the residual Helmholtz energy which accounts for aomalous behavior near the critical point. For pure fluids, the near-critical contribution flattens the coexistence curve and pressure-density isotherms near the critical point. For mixtures, the near-critical contribution has only a small effect on the calculated coexistence curve; this effect is often masked by the choice of binary parameters in the classical equation which have a more profound effect on the calculated results.
    Additional Material: 11 Ill.
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  • 105
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1678-1684 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mass transfer system has been designed to allow transport of only one component and over small changes in concentration. One of the phases was always lamellar liquid crystals, the other was micellar or its inverse structure. It can be argued that the kinetics of phase transformation at the interphase would be important in such systems; in fact, the measurements of individual phase volumes show overshoots that are not explained by classical mass transfer mechanisms. It is suggested that the intermediate structures that are formed during transport are not thermodynamically favored, and consequently the condition of local equilibrium does not hold. Using developments for such systems in diffusion in polymers, the breakdown of local equilibrium has been shown to be adequate in explaining the observations qualitatively. A parallel development for adsorption has not been undertaken.
    Additional Material: 7 Ill.
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  • 106
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1701-1709 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The axial distribution of solid holdup was investigated in a bubble column of 0.07 m in diameter and 4.25 m in height. The particle phase was glass beads of diameter 66, 118, 243, 465 or 1,300 μm. The effective slip velocity and the axial dispersion coefficient of the solid particles were evaluated in batch operation without solids feed and were correlated on the basis of mixing length theory. The equations obtained were applied to analyze axial profiles of particle concentration with a continuous feed of solids, and experimental data in the literature were simulated successfully over a wide range of solid concentration.
    Additional Material: 14 Ill.
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  • 107
    Electronic Resource
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1728-1734 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pulse gas chromatography experiments at ambient pressure are often limited by an overwhelming contribution of axial dispersion to the observed variance and the inability to obtain a quantitative correction for this factor. Theoretically, the axial dispersion contribution can be reduced and at the same time the contribution due to particle diffusion can be enhanced by operating at elevated pressures. Our experiments on methane/helium diffusion in 0.32-cm-diameter commercial catalyst particles confirm this, and a new means of accounting for axial dispersion is demonstrated.
    Additional Material: 8 Ill.
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  • 108
    Electronic Resource
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1749-1752 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 109
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1761-1769 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Methods are described for calculating the effects of hydrodynamic interactions on the hindered transport of solid spherical macromolecules in ordered or disordered fibrous media. These methods are applied to a medium made up of a square lattice of straight, bead-and-string-type fibers. Hydraulic permeabilities and coefficients governing hindered diffusion and convection are obtained from a detailed hydrodynamic model, and the hindered transport coefficients are shown to be in very good agreement with an effective medium approach based on Brinkman's equation. The use of Brinkman's equation for the calculation of hindered transport rates in fibrous membranes and gels is validated further by comparing with experimental data from the literature.
    Additional Material: 7 Ill.
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  • 110
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1803-1812 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Artificial neural networks have capacity to learn and store information about process faults via associative memory, and thus have an associative diagnostic ability with respect to faults that occur in a process. Knowledge of the faults to be learned by the network evolves from sets of data, namely values of steady-state process variables collected under normal operating condition and those collected under faulty conditions, together with information about the degree of the faults and their causes.Here, we describe how to apply artificial neural networks to fault diagnosis. A suitable two-stage multilayer neural network is proposed as the network to be used for diagnosis. The first stage of the network discriminates between the causes of faults when fed the noisy process measurements. Once the fault is identified, the second stage of the network estimates the degree of the fault. Thus, the diagnosis of incipient faults becomes possible.
    Additional Material: 6 Ill.
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  • 111
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1980-1992 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study was made of phenol degradation by bacteria immobilized onto particles of calcined diatomaceous earth in a draft-tube, three-phase fluidized-bed reactor.A mathematical model is used to describe simultaneous diffusion and reaction of oxygen and phenol in the reactor. Kinetic parameters for the growth of nonsupported cells were obtained in batch and chemostat experiments. Liquid-solid mass transfer coefficients were determined experimentally and showed good agreement with literature values for conventional three-phase fluidized beds. Experimental steady-state degradation data were used to calculate biofilm substrate diffusivities. These were found to decrease as the biofilm density increased.The transition from phenol to oxygen-limiting biofilm kinetics predicted by the model was shown to exist experimentally. A critical ratio of phenol/dissolved oxygen concentration was found at which this transition occurred. This provides a criterion for establishing whether increased aeration will increase the volumetric degradation rate.
    Additional Material: 7 Ill.
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  • 112
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 2043-2047 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 6 Ill.
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  • 113
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 869-872 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 114
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 875-875 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 115
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1876-1882 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The precipitation of organic particles from supercritical fluids (SF) by expansion (SFX) has become an interesting alternative to milling without thermal decomposition. Through the rapid expansion process, a dramatic change of the solute supersaturation ratio is created causing subsequent precipitation with a narrow particle-size distribution. It was found that β-carotene precipitates from SF ethylene and ethane have the feed material crystallinity. However, SF CO2 reacted with β-carotene and did not give characteristic β-carotene X-ray spectra. The mean particle sizes of these precipitates were in the submicron range (ca 0.3 μm). Increased solubility was obtained by addition of toluene as cosolvent in SF ethylene. It was found that the mean size of β-carotene particles, generally remained unchanged if the toluene concentration was less than 11/2 mol %. The SFX process appears to be in a single fluid phase when up to 11/2 mol % toluene cosolvent is used.
    Additional Material: 12 Ill.
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  • 116
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1912-1914 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 117
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 2053-2057 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 7 Ill.
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  • 118
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 97-103 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Given the intrinsic kinetics, the tortuosity factor of a Ni/MgAl2O4 catalyst was determined under reaction conditions by minimizing the sum of squares of residuals of the experimental and the simulated conversions. The parallel cross-linked pore model with uncorrelated pore size distribution and orientation was used in the calculation of the effective diffusivities. A modified collocation method was used to obtain the partial pressure profiles of the reacting components in the catalyst pellet. The simulation of the experimental reactor during the optimization of the tortuosity factor also yielded the effectiveness factors of the reactions. The results of the simulation of an industrial steam reformer are also discussed.
    Additional Material: 7 Ill.
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  • 119
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 104-108 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Particle to gas heat transfer studies were carried out for the exothermic benzene hydrogenation and endothermic cyclohexane dehydrogenation reactions on the same catalyst bed. A recirculation type reactor and eggshell type commercial platinum on alumina catalyst were used. When the thermodynamic value for the heat of reaction is used for both reactions in the steady-state energy balance, local JH factors for the exothermic reaction were found to be, in general, higher than those for the endothermic reaction. This was attributed to product molecules leaving the catalyst surface with excess vibrational energy, which implies that the actual heat of reaction would be different than the thermodynamic value used in the JHfactor calculations. The study also indicated significant variations in the local JH factors; these were attributed to variations in the linear velocity in the radial direction.
    Additional Material: 7 Ill.
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  • 120
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 109-119 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Bimetallic Mo-Fe and Mo-Co sulfide clusters were anchored on Al2O3 and used for CO hydrogenation. In addition to methane, significant amounts of dimethyl ether were produced. The reaction orders obtained from power rate laws for methanation indicated that the surfaces of the catalytic ensembles were not completely saturated by CO, in contrast to the observations for most conventional CO hydrogenation catalysts. A kinetic analysis and parameter estimation was performed to identify the rate-determining step for methanation. A catalytic cycle was postulated that could account not only for the formation of methane and higher hydrocarbons, but also for dimethyl ether as a primary product.
    Additional Material: 9 Ill.
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  • 121
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 88-96 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Intrinsic rate equations were derived for the steam reforming of methane, accompanied by water-gas shift on a Ni/MgAl2O4 catalyst. A large number of detailed reaction mechanisms were considered. Thermodynamic analysis helped in reducing the number of possible mechanisms. Twenty one sets of three rate equations were retained and subjected to model discrimination and parameter estimation. The parameter estimates in the best model are statistically significant and thermodynamically consistent.
    Additional Material: 9 Ill.
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  • 122
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 670-672 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 123
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 676-678 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Tab.
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  • 124
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 700-700 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 125
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 875-875 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 126
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 881-890 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An on-line procedure is developed that uses estimates of the dominant eigenvalues of a reactor-exchanger system to detect impending unstable operating behavior. In the event reactor stability is threatened, changes are made in the reactor's nominal operating state through a procedure that ensures the attainment of an accessment is made through estimation of closed-loop eigenvalues derived from a physically-based dynamic model. The guiding of the reactor to safe and stable conditions is carried out through a multiloop control system that receives optimal process setpoints found from an interative search. Experiments were made on a laboratory autothermal reactor system to assess the correspondence of the predicted and observed degrees of reactor stability.
    Additional Material: 9 Ill.
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  • 127
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 931-942 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The dynamic gas disengagement technique is discussed comprehensively in this paper. Also outlined is the procedure for estimating holdup structures and bubble rise velocities in a bubble column, which is extended to include the methodology for estimating the Sauter mean bubble diameter and therefore the specific gas-liquid interfacial area. The error limits for the estimated quantities are established using two extreme cases to describe the disengagement process: constant rate disengagement and interactive disengagement of bubbles. The analysis is done assuming a bimodal bubble size distribution; however, generalized equations for a multimodal bubble size distribution are also presented. Sensitivity of results to the two cases is illustrated using results obtained from experiments conducted with the air-tap water system in two bubble columns (0.05 and 0.23 m in diameter, 3 m tall). Sauter mean bubble diameters and specific interfacial areas estimated using the two approaches provide lower and upper limits for values reported in the literature.
    Additional Material: 8 Ill.
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  • 128
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1631-1638 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Calculations of the ionization constant of H2O are presented for densities ranging from those of subcritical water to those of supercritical steam. A recently-proposed semicontinuum model is used to calculate the standard-state hydration properties for the ions, H3O+, and OH- (Tanger and Pitzer, 1989). Calculated ionization constants are in good agreement with reported measurements at pressures from vapor-liquid saturation to 500 MPa and temperatures from 273 to 1,073 K. These measurements cover H2O densities ranging from ∼ 1,000 to 450 kg · m-3. At H2O densities less than 400 kg · m-3, our calculated ionization constants should be more reliable than those obtained from the commonly-used equation of Marshall and Franck (1981).
    Additional Material: 7 Ill.
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  • 129
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1659-1666 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental results are reported for equilibrium adsorption and diffusivities of CH4, C2H6 and CO2 in type A zeolite containing mixed Na and K cations ranging from 0 to 100% in composition, at two temperatures and 1 atm. Two simple theoretical solutions are given for the diffusivity. One is for diffusion with pore (aperture) blocking using the effective medium approximation, which is readily available from the literature on percolation theory. The other is a kinetic solution derived in this work for cavities containing heterogeneous sites, which is a case where the percolation theory is not applicable. The equilibrium adsorption results show that K+ has a preference for the aperture (or pore-blocking) sites (site type II), and these results are interpreted by the bond percolation theory. The diffusivity results are successfully interpreted by the poreblocking theory in zeolites containing less than 25% K+ and by the kinetic theory for zeolites with higher K+ contents.
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  • 130
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1692-1700 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Previously published conversion data for turbulent diffusion-controlled acid-base reactions in two different multijet reactors are used to extract the mixing parameters, tracer probability density function, and variance. The PDF is obtained with this instantaneous reaction method by differentiating twice the reactive mixing plot of mean reactant concentrations. The limiting behavior for the cases of complete segregation and complete mixing is derived and turns out to be piecewise linear on the reactive mixing plot. The variance is shown to be twice the area between the actual reactive mixing curve and the limiting curve for complete mixing; it can be computed by numerical integration without any foreknowledge of the PDF shape. The method, in principle, allows detection of Dirac delta functions (which represent unmixed virgin fluid) and indeed shows significant amounts of virgin fluid close to the inlet of one of the reactors.
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  • 131
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    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1735-1738 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 132
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    AIChE Journal 35 (1989), S. 1745-1748 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 133
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    AIChE Journal 35 (1989), S. 1791-1802 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of the char-steam gasification reaction and the accompanying pore structure changes have been investigated experimentally and interpreted through the use of the random pore model of Bhatia and Perlmutter (1980) and its extensions developed in this study. To allow model evaluations, surface areas and pore-size distributions were obtained for various partially-reacted char samples. Surface areas follow the reaction rates as a function of conversion, supporting the interpretation that the reaction of porous char with steam is governed by the structural changes that occur as conversion proceeds. Reaction rate constants were obtained from the kinetic data.A pyrolytic change of char mass was observed during the heatup period from room temperature to reaction temperature for each of the two char samples tested. This results in a significant increase in surface area and a decrease in pore structure parameter. It is shown that this pore structure parameter is very sensitive to changes in conversion when the initial parameter is large and the conversion is small.
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  • 134
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    AIChE Journal 35 (1989), S. 1821-1828 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effect of partial external wetting of catalyst particles on conversion for hydrodesulfurization of dibenzothiophene in a white oil was studied in a 25-mm trickle-bed reactor at 10 MPa and 330-370°C with Mo/SiO2 catalyst. The superficial liquid velocity (Lm) was varied from 0.092 to 0.557 kg · m-2 · s-1. Measurements of conversion were augmented by tracer, kinetics and solubility experiments. The objectives were to determine the parameters of a reactor model based on the multizone external wetting (MZEW) model for the overall effectiveness factor, ηo, and to compare the measured and predicted values of ηo. As the wetting efficiency, f, increases, ηo also increases, but, even at the highest Lm, catalyst wetting was not complete and consequently ηo was lower than the value corresponding to f = 1. The MZEW model describes the experimental data better than the simpler two-zone model, based on a particular interpretation of f. The difference between the two models can be as high as 200%.
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  • 135
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    AIChE Journal 35 (1989), S. 1856-1868 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The paper presents a design procedure to generate parity equation models for analytical failure detection and isolation. The models are in “statistically-isolable” structure that prevents incorrect isolation decisions under marginal failure size if the residuals are tested in parallel. Of the combinatorial multitude of structurally-suitable models, a choice is made on the basis of sensitivities with respect to different failures and robustness relative to uncertainties in selected parameters of an underlying model. A complete set of parity equations fitting the isolable structure is first generated from a state-space model. The equations unsuitable for sensitivity are eliminated, and a suboptimally-robust diagnostic model is obtained in a constrained discrete search over the remaining set.
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  • 136
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    AIChE Journal 35 (1989), S. 1894-1894 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 137
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    AIChE Journal 35 (1989), S. 511-513 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 138
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    AIChE Journal 35 (1989), S. 775-792 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A quantitative model of softening coal pryolysis is developed and tested against observed behavior. The model treats intraparticle transport of gases and metaplast throughout the softening stage of pyrolysis via growth of bubbles uniformly dispersed in the molten coal. The model quantitatively describes the transient softening behavior including the initiation, duration, and magnitude of plasticity and swelling of the particle. The model kinetic parameters are derived from experiments, in which a highly softening Pittsburgh No. 8 bituminous coal was pyrolyzed, and total weight loss, and yields and molecular weight distributions of tars and pyridine extractables of cooled chars were measured. Model predictions of effects of pressure, particle diameter and temperature on tar yields and weight losses, of effects of pressure on swelling ratio, and of effects of heating rate on plasticity are presented. The model provides good fits to the laboratory data and predicts trends in pyrolysis behavior in good qualitative accord with expectations based on published data.
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  • 139
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    AIChE Journal 35 (1989), S. 845-848 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
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  • 140
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    AIChE Journal 35 (1989), S. 490-499 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Orthogonal collocation is used to analyze the dispersion and chemical conversion of a multicomponent fluid pulse in a laminar isothermal flow in a catalytic tube. Homogeneous and heterogeneous first-order chemical reactions are included, and a full matrix diffusion law is used. The collocation method represents the dynamics well over wide ranges of system parameters and reaction time. Radial averaging approaches prove less convenient, since the dispersion coefficients thus introduced are complicated functions of time, transport properties and chemical kinetics.
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  • 141
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    AIChE Journal 35 (1989), S. 523-526 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 7 Ill.
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  • 142
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    AIChE Journal 35 (1989), S. 876-876 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 143
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    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 144
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    AIChE Journal 35 (1989), S. 690-693 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 145
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    AIChE Journal 35 (1989), S. 701-701 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 146
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    AIChE Journal 35 (1989), S. 714-724 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Using the principles of conservation of mass and momenturn for each phase, a theory is developed for describing quantitatively the sedimentation of colloidal particles in vessels having electrodes that are inclined to the vertical.As a limiting case, a kinematic settling formula was derived that describes the motion of settling fronts of colloidal alumina particles suspended in tetralin as a function of angle of inclination and strength of applied electric field in terms of electrophoretic mobilities. A hydrodynamic computer model shows the flow patterns and settling behavior of such lamella settlers with and without an applied electric field. The predicted motions of the settling fronts and the thicknesses of the clear boundary layers above the upper wall of the inclined vessels globally agreed with the experimental observations.
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  • 147
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    AIChE Journal 35 (1989), S. 755-763 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The loading of organic molecules adsorbed on high surface area carbon materials can be influenced by the potential of the surface. This phenomenon can form the basis for carbon regeneration and for separation processes. A theoretical treatment demonstrates that adsorption loading becomes more sensitive to potential change when the double layer capacitance of the interface and the size of the organic species are increased. An experimental method was developed to estimate isotherm parameters. The technique was demonstrated on model adsorbates, pentanol and heptanol. The values of the measured isotherm parameters (B = 3.4-9.1 V-2: Emax = 0.36-0.5 V vs. Hg/Hg2 SO4) are in the range of expected values based on literature values for similar systems. Although only 5% of activated carbon surface area was shown to be electrochemically accessible, it still has ten times the area available for electrosorption as compared to the graphite, thus making it attractive for industrial application.
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  • 148
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    AIChE Journal 35 (1989), S. 700-701 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 149
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    AIChE Journal 35 (1989), S. 1177-1185 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A theoretical and experimental study has been carried out on flow, dissolution, and precipitation in porous media. Flow experiments were performed on linear carbonate cores using acidic ferric chloride solutions. Dissolution of the carbonate by the acid causes an increase in the solution pH, thereby precipitating ferric hydroxide. This precipitate plugs up the pore throats in the medium and increases the resistance to fluid flow. Fluctuations in the permeability ratio were observed during core flood experiments, confirming the competition between channel formation due to dissolution and pore plugging due to precipitation. The evolution of the pore structure was characterized by Wood's metal castings.A network model has also been developed to describe flow and reaction in porous media. The model was used to simulate the ferric chloride system, and pressure oscillations predicted by the model show identical trends to those observed experimentally. Additionally, the evolution of pores in the network were graphically represented.
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  • 150
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    AIChE Journal 35 (1989), S. 1215-1218 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 151
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    AIChE Journal 35 (1989), S. 1227-1228 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 152
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  • 153
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  • 154
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    AIChE Journal 35 (1989) 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 155
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    AIChE Journal 35 (1989), S. 30-36 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple one-dimensional mathematical model validated with high-temperature entrained-flow reactor data successfully explained dispersed calcium hydroxide particle surface area evolution resulting from concomitant calcination and sintering. An integrated first-order calcination rate expression and a second-order sintering rate form accurately predicted time-resolved surface area generation and degradation. The effects of water vapor and gaseous carbon dioxide concentration on asymptotic specific surface areas and sintering rates were noted. This methodology for predicting sorbent surface area evolution will enable more accurate sulfation modeling efforts in furnace sorbent injection (FSI) applications, where calcination, sintering, and sulfation can all occur on the same time scale.
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  • 156
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    AIChE Journal 35 (1989), S. 1-29 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Plasma processing has emerged as an important technology for the deposition and etching of thin solid films in the manufacture of microelectronic devices. In fact, much of the progress achieved to date in device miniaturization would have been much more difficult without the unique characteristics of plasma processes. It is anticipated that future progress will continue to rely heavily on plasma technology. Although plasma chemical reactors are widely used, a lack of fundamental understanding has resulted in heavy reliance on empiricism in process design and control. The complexities inherent in any chemical reactor are compounded in plasma processing by the presence and active participation of the discharge in both gas phase and surface chemical processes. This has resulted in a technology that is sensitive to many design and operating parameters. A large parameter space gives process engineers flexibility in tailoring process conditions to meet objectives. However, without fundamental insight into the key physical and chemical processes, reactor design and control cannot be based on systematic, rational procedures. The purposes of this review are to introduce chemical engineers to plasma processing practice and phenomenology; to outline the progress made to date in fundamental studies of discharge physics and chemistry; to indicate areas in which chemical engineers must expand their traditional training to participate in plasma processing research; and finally to suggest how established chemical engineering methodology can be applied to plasma chemical reactors.
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  • 157
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    AIChE Journal 35 (1989), S. 42-52 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Monte Carlo simulation is used to calculate partition coefficients for rigid, axisymmetric, nonspherical molecules in various pore geometries. Novel quantitative results are presented for a variety of molecule and pore shapes, including pores of nonuniform cross-section such as the interstitial space within granular and fibrous materials.Quick estimation methods for obtaining partition coefficients are discussed, and the effects of molecule and pore wall curvature are described in detail. A boundary perturbation analysis is used to derive easy-to-use formulas for a variety of molecule shapes in circular pores.
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  • 158
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    AIChE Journal 35 (1989), S. 37-41 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental data on sulfation rates of CaO particles derived from CaCO3 are compared to those derived from Ca(OH)2 using a product layer diffusion control model differing only in the shape of the CaO grain. Both the model and the experimental data indicate slightly higher reactivity for the Ca(OH)2-derived oxide due to the observed difference in grain shape. This effect is considered as a contributor to the greater performance of Ca(OH)2 in pilot-scale SO2 removal studies.
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  • 159
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    AIChE Journal 35 (1989), S. 53-68 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The equilibrium and rate of uptake of the amino acids phenylalanine and tyrosine by Amberlite 252, a strongly acidic, cation-exchange resin, have been investigated. Uptake of the amino acids by the hydrogen form of the resin occurs primarily by the stoichiometric exchange of hydrogen ions and amino acid cations. The amount of amino acid taken up by the resin can be calculated as a function of solution pH and amino acid concentration from a model that takes into account both solution and ion-exchange equilibria. The rates of uptake of the two amino acids have been determined experimentally for a closed batch system. The results of experiments in which the resin particle size, the flow rate, and the concentration were varied show that intraparticle transport is dominated by the slow diffusion of amino acid cations through the macroreticular polymer structure of the resin, with some contribution from macropore transport of amino acid cations and zwitterions. An intraparticle diffusion model has been developed to describe these results and predict the performance of fixed-bed operations.
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  • 160
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    AIChE Journal 35 (1989), S. 75-87 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The concepts of coherence and composition paths, originally developed for multicomponent chromatography, are used to establish a simple theory of transport in systems with precipitation and dissolution in the course of multicomponent, single-phase flow in permeable media. Composition route construction in phase diagrams in combination with distance-time diagrams yields concentration profiles without recourse to trial-and-error procedurs. Detailed results are given for systems with three ions A, B, and X and up to two precipitates AX and BX. The extension to systems with additional, nonprecipitating species is described. The new approach confirms most conclusions of Bryant's earlier theory, removes assumptions stipulated in the latter, and is simpler to handle.
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  • 161
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    AIChE Journal 35 (1989), S. 69-74 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Certain nonfunctional macroreticular polymeric adsorbents are nonwet by suffciently dilute aqueous solutions and enable separations not achievable with adsorbents in the prewet state. Fixed-bed adsorption data were obtained for a multisolute aqueous solution containing acetic acid, 1,3-butanediol, and succinic acid, with Porapak Q and Amberlite XAD-4 as adsorbents in both the prewet and nonwet states. The prewet breakthrough data agree with a model allowing for axial dispersion and a linear rate law, using independently estimated parameters. Break-through curves for the nonwet case depend strongly upon solute volatility since mass transport within the particles appears to occur by Knudsen diffusion, and is rate limiting. Data for Porapak Q reflect an effective particle diffusivity about ten times lower than for Amberlite XAD-4.
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  • 162
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    AIChE Journal 35 (1989), S. 168-172 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 8 Ill.
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  • 163
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    AIChE Journal 35 (1989), S. 148-158 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A computer-generated slim tube randomly packed with spheres of almost uniform size is used to model single-phase flow in a packed tube with a small tube diameter to particle diameter ratio, R. To obtan a detailed description of its morphology, the slim packed tube is first tessellated into tetrahedra in the interior, and pentahedra near the walls of the tube. Then, the pore space is represented by a network of interconnected circular and triangular sinusoidal flow channels. The size and length of each channel, as well as their interconnectivity, are exactly known. In addition, porosity and solid surface area per unit volume of the porous medium are determined as a function of distance away from a wall. These data suggest that the presence of the walls has two counteracting effects on fluid flow. A higher porosity promotes flow along the walls but a higher surface area per unit volume hinders it. To confirm this prediction, experimental permeability data are obtained for tubes with R between 2.5 and 40. For R 〉 25, the permeability is the same as that of a large diameter tube, k∞. Between 8 and 25, the permeability can be larger or less than k∞. The way the tube is packed determines whether the higher porosity or surface area dominates in the wall region, and thus higher or lower permeability. Below R = 8, the confining walls cause a marked increase in overall bed porosity and the permeability is always larger than k∞. Theoretical predictions of the permeability of such very slim tubes are in good agreement with experimental data.
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  • 164
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    AIChE Journal 35 (1989) 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 165
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    AIChE Journal 35 (1989), S. 177-186 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A long-wave equation for film thickness as a function of position is derived for a general case incorporating viscous, surface tension, and interfacial shear effects. The derivation considers both the parabolic and the power-law velocity profiles. The analysis is aimed at revealing the wave velocity that induces infinitely long (homoclinic) periods as well as substrate thickness and wave peak amplitude. Phase plane analysis shows that at Re ≫ 1, due to time-scale separation, the homoclinic velocity is near that at the Hopf bifurcation. That enables analytical derivation of the wave characteristics.Comparison with experimental results in the range of Re-310-3, 100 with countercurrent gas flow, shows encouraging agreement. At very high Re the wave velocity suggests the onset of turbulence, in agreement with theory. Phase plane analysis predicts also that the wave shape consists of a simple peak with a steep front, with short waves riding on the main wave at low Re.
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  • 166
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    AIChE Journal 35 (1989), S. 213-222 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A stable Kalman filter predictor (KFP) is developed which generates minimum variance estimates of the future outputs {y(t + i | t), i = 1, … d} of stochastic, single-input/single-output processes with time delay, d. The predicted outputs are used for time delay compensation and in the design of a predictive feedback controller. An innovation model analysis is used to convert the state space formulation to transfer function form and to show the relationship between the KFP, the Smith predictor, and the internal model controller. A modified KFP includes a disturbance model, and eliminates offset due to deterministic disturbances (e.g., steps) and modeling errors. Simulation results show that the modified KFP also predicts the disturbances and gives significantly better performance than the Smith predictor, particularly in the presence of process and measurement noise.
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  • 167
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    AIChE Journal 35 (1989), S. 196-212 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Numerical solutions for the creeping motion of a spherical particle in a linear axisymmetric straining flow normal to a deformable interface are presented for a range of viscosity ratios, capillary numbers, and Bond numbers. The parameter ranges investigated have applications in areas of flotation (small interface deformation) and material processing (large interface deformation). The accuracy of previous solutions for flotation problems which neglect interface deformation is considered, along with the magnitude and form of interface deformation “defects” which may appear in material processing applications involving fluids containing bubbles or small particles.
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  • 168
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    AIChE Journal 35 (1989), S. 230-240 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The unsteady, impulsive motion of a compressible bubble expanding out of a constricted capillary is quantified with a macroscopic momentum balance. Numerical solution demonstrates the importance of the Ohnesorge number, the geometry of the constriction, the length of the initial gas bubble, and the surface tension, density, and unconstricted capillary radius, which combine to form a characteristic scaling time. Experimental data for the position of the bubble front as a function of time confirm the theoretical result when the time scale for the bubble jump is longer than that required to achieve fully developed parabolic flow. Theory also predicts the capillary number of the bubble jump which, in conjunction with previous theoretical results, determines the time to snap-off of gas bubbles moving through constricted capillaries. Excellent agreement is found with existing experimental data for Ohnesorge numbers ranging from 5 × 10-3 to 0.3.
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  • 169
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    AIChE Journal 35 (1989), S. 259-266 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A dynamic model is derived for simultaneous, homogeneous and heterogeneous, first-order reactions in a slurry reactor. The theory is applied to experimental data for the oxidation (with gaseous oxygen) of aqueous sulfite solutions which is first order in oxygen and zero order in sulfite. The homogeneous reaction is very slow at low pH (2-3) where the sulfur exists as dissolved SO2 or HSO3-, even when cobalt is added as a homogeneous catalyst. At higher pH (7-8.5), considerable homogeneous reaction occurs with and without cobalt ions. Here the predominant species are SO3= and HSO3-. Activated carbon is not a heterogeneous catalyst at pH 7 or 8.5, but is responsible for nearly all the reaction at the low pH values. Analysis of the heterogeneous data indicates that the surface reaction between adsorbed oxygen and SO2 controls the rate rather than adsorption of oxygen.
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  • 170
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    AIChE Journal 35 (1989), S. 279-286 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to describe the translational diffusion of polymers in dilute solution, an elastic dumbbell model is used for which the effects of both hydrodynamic interaction and a nonlinear connector force are treated in a self-consistently averaged form. For this model, the diffusion tensor in the presence of a homogeneous flow field is obtained from (i) the mass flux caused by concentration gradients, (ii) the average polymer velocity caused by external forces, and (iii) the mean-square displacement of a polymer caused by the Brownian forces. From the second and third approaches the same expression for the diffusion tensor is found, whereas a different expression is obtained from the first approach. This means that the Nernst-Einstein equation cannot be generalized to the case of flowing solutions. The model predictions for the diffusion tensors in steady shear flow are discussed in detail.
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  • 171
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    AIChE Journal 35 (1989), S. 287-292 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Multitubular reactors of the heat exchanger type are commonly used to carry out highly exothermic reactions. Two of the main goals, when designing this type of reactor, are to guarantee a safe operation and to minimize the reactor length. Therefore, these concepts are used here as criteria for comparing the performance of the three most common cooling-medium flow arrangements. The analysis of the parametric sensitivity behavior, as well as that of some related measures, indicates that, at least from the steady-state standpoint, the cocurrent arrangement should be considered the most attractive alternative.
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  • 172
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    AIChE Journal 35 (1989), S. 311-313 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 173
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    AIChE Journal 35 (1989), S. 293-299 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The model proposed by Chen et al. for treating nonideality in concentrated electrolyte solutions has been extended to the correlation of the densities of solutions of single electrolytes (1:1, 2:1, 1:2, and 2:2) in terms of Chen's energy interaction parameters τca,m and τm,ca. At any single temperature, only three adjustable parameters, V20 (the partial molar volume of the solute at infinite dilution), and the pressure derivatives (δτca,m/δp)T and (δτm,ca/δp)T are required for correlating the density as effectively as the conventional treatment employing a power series in (molality)1/2. For some electrolytes, only the latter two parameters are required, as tabulated V20 values also lead to satisfactory correlations. The treatment can be extended to cover the temperature range 0-100°C, using either τca,m and τm,ca values derived from activity or osmotic coefficients, or constant τm,ca and τca,m values, but the irregular variation with temperature of the pressure derivatives precludes their representation by simple analytical functions, and individual values of the pressure derivatives at each temperature are necessary.
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  • 174
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    AIChE Journal 35 (1989), S. 355-364 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experiments were conducted to study the hydrodynamics of a gas-liquid-solid fluidized bed containing low-density particles. The density and size of the particles employed were comparable to those ordinarily encountered in fluidized-bed bioreactors for either wastewater treatment or fermentation. A dual resistivity probe and a conductivity probe were employed to study the axial holdup of gas and liquid phases and the bubble size distribution. The behavior of the axial holdup distribution for solid, gas, and liquid phases is reported. A mechanistic model, based on solids entrainment and deentrainment mechanisms by bubbles, is developed to describe the behavior of the axial solids holdup distribution. The model is shown to satisfactorily account for the experimental data.
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  • 175
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    AIChE Journal 35 (1989), S. 385-392 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A model is developed for fluid-solid reaction kinetics in a porous solid. The model is based on a convergent-divergent pore structure and accounts for pore blockage and inside cavities. A numerical study applied the model to the process of coke removal for catalyst regeneration. The calculated results show that in the presence of pore occlusion, the reaction rates are significantly reduced at the beginning of reaction. At higher levels of coke loading the reaction behavior can be especially affected by the volume fraction of the divergent pores. This behavior can be used to select catalysts with pore structures that improve control of the regeneration process.
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  • 176
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    AIChE Journal 35 (1989), S. 415-422 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The non-Newtonian viscosities of polymerically stabilized colloidal suspensions are usually predicted and correlated on the basis of data and scaling principles for Brownian hard spheres. Here, the specific effect of the stabilizer layer is investigated using suspensions of monodisperse PMMA particles with a chemically attached stabilizer layer. The ratio between particle radius and stabilizer layer thickness is changed between 5 and 61. At high values of this ratio the data show Brownian hard sphere behavior. At lower values deviations appear. As a first approximation, the “softness” of the particles can be characterized through the concentration at maximum packing. A more detailed comparison with hard sphere data provides a measure for softness that changes with concentration and shear rate. A theoretical estimate of the concentration effect is in line with the experiments. The critical shear stress (or Peclet number) is not a constant but goes through a maximum when the concentration is increased.
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  • 177
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    AIChE Journal 35 (1989), S. 393-405 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gas holdups (∊GR) and liquid-phase volumetric oxygen transfer coefficients (kLaT) were measured for a bubble column (BC) and three different external-circulation-loop airlift (ECL-AL) fermentors of 50 to 60 L working volume, using viscous non-Newtonian aqueous solutions of various carboxymethylcelluloses. Some measurements also were done with a viscous Newtonian system (51.8 wt. % sucrose solution).Discussed in this paper are correlations of ∊GR and kLaT with riser superficial gas velocity (0.02 ≦ UGR ≦ 0.26 m/s), the ratio of the downcomer and riser crosssectional areas (0[BC] ≦ Ad/Ar ≦ 0.444), and the effective viscosity of the liquid phase (0.02 ≦ ηeff ≦ 0.5 Pa · s), over the parameter ranges indicated. It is shown that both ∊GR and KLaT are highly dependent upon UGR and Ad/Ar. The effective viscosity has a significant effect on KLaT, but has only a relatively weak affect on ∊GR. The KLaT correlation developed for non-Newtonian systems was extended to include the results obtained for the viscous Newtonian system studied by incorporating the effects of liquid-phase molecular diffusivity, density, and interfacial tension as determined by Nakanoh and Yoshida (1980).
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  • 178
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    AIChE Journal 35 (1989), S. 500-506 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A calcium hydroxide [Ca(OH)2] sorbent modified by the addition of calcium lignosulfonate has recently been developed for use in the Environmental Protection Agency's limestone injection multistage burner process. The increased reactivity with sulfur dioxide (SO2) displayed by this modified sorbent has been shown to be caused, in part, by its decreased particle (agglomerate) size compared to conventional Ca(OH)2. Subsequent work has shown that surfactant-modified Ca(OH)2 also undergoes significantly different structural changes during furnace injection. For a given reactor temperature and residence time, the modified sorbent calcines to a greater extent than unmodified sorbent. It also loses surface area more slowly, and retains more of its porosity, suggesting that it sinters more slowly than conventional sorbent. Therfore, in addition to reducing the particle size of Ca(OH)2 in some applications, calcium lignosulfonate also to inhibit one or more of the diffusion mechanisms responsible for the process of sintering.
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    AIChE Journal 35 (1989), S. 519-522 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 180
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    AIChE Journal 35 (1989), S. 533-538 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A lumping procedure proposed previously is applied to two types of continuous reaction mixtures: one in which the constituents undergo reactions of a Langmuir-Hinshelwood (LH) type, the other in which the constituents undergo reactions of a bimolecular type. It is shown that both mixtures initially can behave qualitatively like lumped first-order reactions. At large times, the behavior of the lumps can be described by power law kinetics, with the bimolecular lump displaying a higher overall reaction order. In particular, if the feed contains a nonzero amount of unconvertible species, the LH lump at large times decays at a second-order rate, whereas the bimolecular lump decays at a third-order rate. To complement the asymptotic results, expressions describing the behavior of the lumps at any time are derived.
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  • 181
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    AIChE Journal 35 (1989), S. 658-661 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Tab.
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  • 182
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  • 183
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    AIChE Journal 35 (1989), S. 877-877 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 184
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    AIChE Journal 35 (1989), S. 1233-1244 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The purpose of this work is to introduce the notion of synthesizing mass-exchange networks (MEN's). A systematic, two-stage, procedure is proposed for the synthesis of cost-effective MEN's. In the first stage, a thermodynamically-oriented procedure is used to identify the thermodynamic bottlenecks (pinch points) that limit the extent of mass exchange between the rich and the lean process streams. Preliminary networks, that feature maximum mass exchange, are generated at this stage. The objective of the second stage is to improve the design of these preliminary networks so as to develop a final configuration of the MEN that satisfies the assigned exchange duty at minimum venture cost. This approach is applied to the synthesis of MEN's with single-component targets as well as multicomponent, compatible targets. An illustrative example on the sweetening of coke-oven gas is presented to demonstrate the applicability of the proposed synthesis procedure.
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  • 185
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    AIChE Journal 35 (1989), S. 1465-1472 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents a simple linear model based self-tuning controller (STC) for MIMO systems. The controller, namely the cautious selftuning controller (CSTC), features enhanced robustness characteristics in the case of unmodeled nonlinearities and / or dynamics. The controller structure is that of a linear quadratic, minimizing a single-step cost function, and with time varying input penalization. The CSTC can be applied to open-loop stable and minimum-phase systems. Application to a simulated distillation column demonstrates its effectiveness.
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  • 186
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    AIChE Journal 35 (1989), S. 1527-1534 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mass transfer analysis of the oxygen transfer performance of diffused air or subsurface mechanical aeration systems has progressed very little over the past 20 years. The recently-developed ASCE Standard method for determination of the oxygen mass transfer performance of diffused or subsurface aeration systems is based on a greatly over-simplified mass transfer model. Although the ASCE Standard can be used to empirically evaluate point performance conditions, it does not provide a meaningful representation of the actual mass transfer process and is not capable of accurately assessing or predicting performance under changing operating or environmental conditions. A new oxygen mass transfer model has been developed which is a fundamentally more rigorous description of the actual mass transfer process in diffused aeration systems. This model can be confidently used to predict aerator performance under changing operating and environmental conditions. The model is easily adapted to numerical computer solution for routine aeration systems performance evaluation as well as process design.
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  • 187
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    AIChE Journal 35 (1989), S. 1555-1558 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 188
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    AIChE Journal 35 (1989), S. 1572-1574 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 3 Ill.
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  • 189
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    AIChE Journal 35 (1989), S. 1585-1591 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple design technique for heterogeneous distillation columns has been developed. The underlying geometric conditions which govern minimum reflux are shown to share certain common features with homogeneous distillations, but differ in some important respects. It is shown that heterogeneous columns display some unusual sensitivities to the design parameters. The most notable being the drastic swings in the composition and temperature profiles with very small changes in the level of trace impurities in the product stream.
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  • 190
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    AIChE Journal 35 (1989), S. 1916-1916 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 191
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    AIChE Journal 35 (1989), S. 1953-1961 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A previously developed method (Sotirchos and Burganos, 1988) for studying isobaric multicomponent diffusion in a class of capillary networks is extended for application to the problem of convection and diffusion of gaseous mixtures in porous media. The method is used to develop flux models for nonisobaric transport in capillary structures, which are then compared with corresponding “three-parameter” dustygas models. Results for discrete and continuous pore size distributions show that the predictions of the developed flux models depend strongly, both qualitatively, and quantitatively, on the procedure used to average the dusty-gas model equations for a single pore over the pore-size distribution.
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  • 192
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    AIChE Journal 35 (1989), S. 2003-2012 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ceramic particle formation processes have been studied using SiO2 as a model compound. Silica particles have been synthesized in a counterpropagating diffusion flame reactor, in which in-situ measurements of particle size and number density have been made. In addition, the time-temperature history of the particle field has been calculated from a flame simulation. Numerical simulations using moment and sectional methods for particle formation have been applied and compared to the experimental measurements. The simulations for the particle formation assume a kinetically-constrained approach, allowing a simple representation of nucleation, surface growth and coagulation. The results suggest that, if the source rates are known well enough, particle formation of low vapor pressure species can be predicted. Both models do well in predicting the gross features of particle formation (number density and mean particle size), although the moment solution does a poor job of predicting the polydispersity effects during periods of high monomer generation rates.
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  • 193
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    AIChE Journal 35 (1989), S. 187-195 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three isolated waves of differing amplitude and shape were selected from experimental measurements of a falling liquid film at Re = 880 for study using an algorithm developed for solution of the Navier-Stokes equations. The method computes the velocity and pressure fields as well as the velocity of the wave. The results show that large streamwise accelerations exist along with regions of recirculating flow in a moving coordinate system. These features can explain the enhanced rates of heat and mass transfer observed in wavy film flow. Computed wave velocities and wall shear stress were in reasonably good agreement with measurements. Wave velocity is shown to be sensitive to small variations in the wave shape and explains the apparent random variation of wave velocity with amplitude that has been observed experimentally. This numerical experiment points to the shortcomings of the many methods used to model large waves on falling films that have been based on parabolic velocity profiles.
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  • 194
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    AIChE Journal 35 (1989), S. 339-342 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 195
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    AIChE Journal 35 (1989), S. 353-353 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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  • 196
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    AIChE Journal 35 (1989), S. 406-414 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The pipeline mixing of two fluid streams by turbulent jet injection normal to the pipeline has been studied theoretically and experimentally. A simple scaling law for the second moment of the tracer concentration within the pipeline is proposed for the first fifteen pipe diameters down-stream from the injection point. The similarity solution is derived by assuming that the tracer diffuses in a weak compound jet moving parallel to the pipeline axis. The theoretical results are correlated with all of the available experimental measurements. The results indicate that the second moment of the tracer concentration decreases with increasing jet momentum and distance from the injection point such that M = 0.25. (lm/D)-2 (x/D)-4/3.
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    AIChE Journal 35 (1989), S. 443-448 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The infinite dilution diffusion coefficients of methane, ethane, n-propane, n-pentane, n-heptane, n-decane, n-dodecane, and n-tetradecane have been measured in n-octane using the Taylor dispersion technique in the temperature range 304-435 K at 1.72 × 106 N/m2. Using the framework of the rough hard sphere theory, the values of the translation-rotational coupling parameter have been determined for each solute-solvent pair at each temperature. The coupling parameter was found to be independent of temperature over the entire temperature range of the experiments performed and it has the same value for solutes ranging from n-pentane to n-tetradecane. A calculation scheme is presented for accurate determination of infinite dilution diffusion coefficients for a wide range of solutes in n-octane at a wide temperature range.
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  • 198
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    AIChE Journal 35 (1989), S. 466-480 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A numerical study has been conducted for the flow of a dilute particleladen gas moving past one or more tubes undergoing erosion. A nonor-thogonal body-fitted coordinate system was used to calculate three tube configurations for laminar and turbulent flow regimes. The assumption of one-way coupling allows the calculation of individual particle velocities from the fluid flow field. The significant effects of turbulent velocity fluctuations are taken into account by means of the stochastic separated flow model. The particle flow field information is then used to predict circumferential distributions of particle flux and erosion. Predictions of trajectories for the case of two in-line tubes show that particles with inertia numbers λ 〉 1 will strike many tubes in a tube bank due to particle rebounding from tube surfaces. By contrast, particles with λ 〈 1 are entrained in the bulk flow between tubes. In general, the effect of increasing the particle-gas suspension temperature is to couple the particle-fluid motion more closely through viscous drag and, thus, to decrease erosion.
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  • 199
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    AIChE Journal 35 (1989), S. 481-489 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A semitheoretical group contribution method for predicting pure-compound second virial coefficients is proposed. An expression for the second virial coefficient, expressed as the product of a nonpolar and a polar contribution, is derived using statistical thermodynamic concepts and an approximate form for the radial distribution function. For polar compounds the nonpolar contribution is assumed to be given by the Tsonopoulos correlation with the nonpolar acentric factor defined by Thompson and Braun. The polar contribution is represented by an energetic term expressed in terms of group contributions. Second virial coefficient predictions for strong polar and associating systems are comparable with those obtained with the correlations of Tsonopoulos and Hayden and O'Connell. Cross-second virial coefficients for mixtures obtained using well-defined molecular mixing rules compare well with literature values.
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    AIChE Journal 35 (1989), S. 549-558 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Configuration of feedback loops between input and output variables of a given plant constitutes a subtask of control system synthesis. In the past, this subtask has been tackled through direct decomposition of either the process or the set of input-output variables. Linear interaction analysis has been used in both approaches to assess and minimize sub-system interactions. Since most chemical processes exhibit nonlinear behavior, it is evident that a measure is needed for assessment of interactions in the presence of system nonlinearities. In this paper we focus on input-output variable set decomposition and introduce the notion of nonlinear block relative gain (NBRG) as a nonlinear interaction measure. Both the statistic and dynamic versions of NBRG are discussed, and a computational procedure is presented for their evaluation. Direct simulations on a CSTR verify the interactions predicted by NBRG for different feedback configurations. Moreover, nonsymmetry of the effect of one loop on another, a fact not captured by the linear BRG, is accurately predicted by NBRG.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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