STUDY OF THE PARAMETRIC SENSITIVITY OF TUBULAR REACTORS
When carrying out exothermic reactions in tubular reactors with external heat exchange, as is known, a problem arises associated with parametric sensitivity. The main task considered in the study of sensitivity is to analyze the effect of small changes in design parameters and external conditions on the operating mode of the reactor. In this work, using the example of the oxidation reaction of xylene to phthalic anhydride, the most influential technological parameters of a tubular reactor are determined. A mathematical model of the reaction is constructed, which describes the dynamics of a tubular reactor using the equations of material and heat balance. The parametric sensitivity of the reaction zone temperature was studied in terms of the parameters G (surface mass velocity), d (reactor diameter), T<sub>0</sub> (initial temperature), T<sub>x0</sub> (initial temperature of the cooling agent), mA (molar fractions of raw materials), and m<sub>O2</sub> (molar fractions of initiator). The maximum sensitivity for all parameters is achieved in the temperature range corresponding to the inflection in the temperature profile. This character of the sensitivity change is quite typical for tubular reactors and should be taken into account when constructing their control systems. The fact of the high sensitivity of the operating variables to the variation of the input values at the beginning of the reaction zone shows that it is necessary to have the most accurate data on the input values of the variables. When controlling the reactor, it is necessary to keep in mind that small perturbations of the initial temperature of the reaction zone and the initial temperature of the cooling agent can lead to a rapid and significant increase in the reaction temperature.