The selective oxidation of ethene over a silver on a-alumina catalyst
was studied in a pilot plant with a wall-cooled tubular packed bed rea
ctor. Gas and solid temperatures in the catalyst bed were measured at
different axial and radial positions as well as concentrations at diff
erent axial position. Total pressure, inlet mole fraction ethene, mass
flow rate and wall temperature were varied. The experiments are compa
red with model calculations. A pseudo-homogeneous model and a heteroge
neous two-dimensional model were used for the calculations. Kinetics a
nd heat transport parameters in the model have been determined indepen
dently in separate studies. The work is distinctive in the accuracy pa
id to a large number of experimental details. The models correspond re
asonably well with the experiments at all operating conditions. The ma
in problem in the description of the reactor is the inability of the k
inetic expressions to predict the reaction rates over the entire range
of partial pressures. As a result some systematic deviations are foun
d, in particular in the predicted temperature profiles. The heterogene
ous model gives better agreement with the experiments although systema
tically larger temperature differences are calculated on the basis of
available correlations in literature than has been measured. On the ba
sis of this work it is difficult to determine directly whether an infl
uence of chemical reaction is present on the values of the heat transp
ort parameters.