Case Studies for the Evaluation of Kinetic Data

Concept of Effective Reaction Volume for Non-lsothermal Tubular Reactors The 

In contrast to investigations with solid catalysts, where we can place the catalyst in a small and almost isothermal zone, we have to accept non-isothermal operation in the case of a homogeneous gas phase reaction. It is, therefore, required to determine the kinetic parameters by means of an effective reaction volume. VR efr is defined as the volume needed to reach the same conversion at a constant reference temperature T ef as under the non-isothermal conditions with an axial temperature Tx. Tref can be arbitrarily chosen, for example, the temperature at a fixed position in the middle of the tube. This definition leads to  

The rate tn of naphthalene conversion depends on the concentrations of naphthalene, hydrogen, and steam, which may be expressed by a general function Cj), as well as on the rate constant fen, which strongly depends on the axial temperature Introduction of the cross-sectional area and length of the reactor, Ar and Lr, respectively, then leads to  

In comparison to the strong influence of temperature on according to Arrhenius s law, we may neglect the small change in concentrations with temperature, and Eq. (4.11.29) simplifies to  

Determination of Kinetic Parameters of Thermal Conversion of Naphthalene 

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