N2

— Temp.

Fig.1: Temperature and concentration profiles calculated by the model version which doesn't take radial effects into account (approximate model).

Reactor dimensionless length

Fig.2: Temperature and concentration profiles calculated by the model version which lakes radial effects into account (complete model).

Inspection of these figures reveals that the modifications introduced into the final version of the model affected the results with dissimilar influences on the concentration and temperature profiles. Main results can be summarized as follows:

• all modifications showed-a negligible influence on the concentration profiles, which do not vary significatively in comparison with the values of the previous model version;

• the introduction of different mass transfer coefficients resulted in a negligible effect on the temperature profile, providing temperatures slightly higher with respect to the approximate version of the model but without any change in the shape;

• the irradiation and dispersion contributions influenced the shape of the temperature profile; in fact, the temperature increased in the first part of the catalytic bed in comparison with the results obtained when these effects were neglected (the peak is about 70°C higher than the value of the approximate model, and its localization is slightly shifted). Otherwise it decreased more gradually in the last part of the catalytic bed;

• the agreement between the simulation results and the experimental ones has been further improved (Fig.3).

Temperature,K

Conclusions

0 0

Post a comment