Browsing by Author "Asbjornsen, O.A."

Now showing 1 - 4 of 4
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    Error in the Propagation of Error Formula.
    (1987) Asbjornsen, O.A.; ISR
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    Estimation of Reaction Kinetic Parameters by Local Online Experimentation.
    (1987) Asbjornsen, O.A.; Robinson, P.S.; ISR
    In the control of chemical reactors, it is important to know the kinetic parameters of the reaction with good precision. The traditional approach is to try to estimate them from laboratory experiments or from plant records, where variations due to control or to disturbances may occur. However, this may happen only sporadically in the plant history because the reactor is at steady state for long periods of time. It would be advantageous to experiment online, so that the estimation of the kinetic parameters could be made more accurately and independently of plant changes.
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    Modeling Techniques: theory and practice.
    (1987) Asbjornsen, O.A.; ISR
    A survey is given of some crucial concepts in chemical process modeling. Those are the concepts of physical unit invariance, of reaction invariance and stoichiometry, the chromatographic effect in heterogeneous systems, the conservation and balance principles and the fundamental structures of cause and effect relationships. As an example, it is shown how the concept of reaction invariance may simplify the homogeneous reactor modeling to a large extent by an orthogonal decomposition of the process variables. This allows residence time distribution function parameters to be estimated with the reaction in situ, but without any correlation between the estimated residence time distribution parameters and the estimated reaction kinetic parameters. A general word of warning is given to the choice of wrong mathematical structure of models.
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    On-Line Estimation of Heat Capacity of Process Fluids Using Dynamic Excitation of Temperature.
    (1987) Beerel, Gustav H.; Asbjornsen, O.A.; ISR
    In process control involving energy balances the heat capacity of the process fluid is needed. Although many methods for accurate heat capacity measurements are available for the laboratory, an instrument for online heat capacity measurement has yet to be successfully developed.