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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 337-345 
    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 monolith froth reactor, involving two-phase flow and a monolith catalyst, is developed. The flow within monolith channels, consisting of trains of gas bubbles and liquid slugs, is produced by forming a two-phase froth in a chamber immediately below the bottom of the monolith. The froth then flows upward into the monolith channels through pressure forces, which differs from previous methods since it may be carried out for a commercial-scale reactor. Because the liquid film which develops between the gas phase and the surface of the catalyst is extremely thin, two-phase flow within a monolith can provide reaction rates which are near their intrinsic values. Catalytic oxidation of aqueous phenol over copper oxide supported on γ-Al2O3 is used as a model reaction for investigating reactor performance. Generation of a froth is confirmed by visual inspection; the average bubble size is approximately that predicted by a force balance. The effect of externally controllable process variables (liquid and gas flow rates, temperature, and pressure) on the rate of phenol oxidation was investigated. Reaction rate increases with temperature or pressure increase and decreases with gas flow rate increase, achieving a maximum with respect to liquid flow rate. The activation energy calculated from the apparent reaction rate measured in the monolith froth reactor is similar to that of intrinsic value, suggesting minimal mass-transfer limitations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 16 (1970), S. 916-924 
    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 time optimal control problem for jacket cooled continuous flow stirred tank reactor (CSTR) with an exothermic, irreversible, second-order, homogeneous, liquid-phase reaction (the saponification of ethyl acetate) was solved with the maximum principle and phase plane analysis. Both experimental studies and analogue computer simulation studies were conducted.The overall performance of the experimental system agreed very well with the performance of the corresponding system simulated on an analogue computer. However, there were enough differences in the observed and predicted operating states and switching curves to warrant the conclusion that the experimental performance can be significantly improved if experimental results are used to modify the results predicted with computer analysis. These differences were attributed to uncertainties in the model and the values of the model parameters as well as nonrandom (and unforeseen) measurement errors.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 41 (1995), S. 649-657 
    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 residence time distribution of the liquid phase within a three-phase monlith reactor is determined using tracer studies. The actual liquid residence time in the monolith, relevant for reactor design purposes, is calculated from overall residence time measurements using deconvolution by Fourier transform. The liquid-phase residence time decreases as liquid or gas flow rates increase, but the reactor Peclet number remains approximately constant. The residence time distribution and calculated values of the Peclet number reveal that the liquid phase is substantially well-mixed. Comparison with results from experiments in a single glass capillary reveals that the monolith channels become predominantly liquid-filled, particularly as the liquid flow rate becomes a significant fraction of the total flow rate.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Silicon-based microfabrication of a novel chemical reactor (microreactor) having submillimeter flow channels with integrated heaters, and flow and temperature sensors is described. The potential application of this reactor to partial-oxidation reactions is explored by using Pt-catalyzed NH3 oxidation as a model reaction. Investigation of reactor behavior as a function of operating conditions shows that conversion and selectivity behavior of conventional laboratory reactors can be reproduced and demonstrates the feasibility of conducting chemical reactions in microfabricated systems. Ignition-extinction behavior is explored, along with high-temperature microreactor materials degradation. Potential applications and scale-up of microreactors are also discussed.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 42 (1996), S. 1995-2004 
    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 water oxidation has become a well-known treatment technology for conversion of aqueous wastes. By introducing a catalyst, higher conversion and selectivity to carbon dioxide can be achieved at a lower temperature and at shorter residence times. The stability of chromium oxide in supercritical water was studied to determine the feasibility of using catalysts during supercritical water oxidation. Various process variables, including oxygen and water concentrations, fluid flow rate, and temperature were found to affect the reactivity of the chromium oxide catalyst. Under these conditions, chromium was present in the reactor effluent as chromic acid, H2CrO4. The visual observation of the catalyst after the completion of the experiments suggested that a reaction front moved along the length of the reactor. A rate expression, based on Langmuir-Hinshelwood kinetics, with dissociative chemisorption of oxygen on a hydrated chromium oxide surface, was proposed. The model, developed based on this rate expression and the continuity equation for the fluid phase, was consistent with the experimental results.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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