Startup strategy design and safeguarding of industrial adiabatic tubular reactor systems

Authors

  • J. W. Verwijs,

    1. Process Development & Control Dept., Dow Benelux N.V., 4530 AA Terneuzen, The Netherlands
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  • H. van den Berg,

    1. Process Development & Control Dept., Dow Benelux N.V., 4530 AA Terneuzen, The Netherlands
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  • K. R. Westerterp

    Corresponding author
    1. Chemical Reaction Engineering Laboratories, Dept. of Chemical Engineering, Twente University, 7500 AE Enschede, The Netherlands
    • Chemical Reaction Engineering Laboratories, Dept. of Chemical Engineering, Twente University, 7500 AE Enschede, The Netherlands
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Abstract

The safeguarding methodology of chemical plants is usually based on controlling the instantaneous values of process state variables within a certain operating window, the process being brought to shutdown when operating constraints are exceeded. This method does not necessarily prevent chemical reactors suffering from a runaway during dynamic operations because (a) excessive amounts of unreacted chemicals can still accumulate in the process, and (b) no means are provided to the operating personnel to identify hazardous process deviations. A model-based startup and safeguarding procedure is developed for an industrial adiabatic tubular reactor to improve process safety during startup. The trajectories of manipulated variables are calculated by minimizing the amount of one of the main reactants in the reactor effuent. It is concluded that proper control of the initial reactor temperature profile is critical for a safe startup while the impact of other manipulated variables is relatively smaller than that of the initial reactor temperature profile.

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