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Abstract-Thesteady-state and dynamic behaviour of a single Pd-AI,Os catalyst particle is studied for the selective hydrogenation of ethyne in the presence of ethene, without addition of carbon monoxide. The particle-to-gas heat transfer in the reactor is characterized. During selective hydrogenation, not only the ignition and the extinction phenomena but also oscillatory behaviour is observed. The nature of the single and multipeak oscillations is discussed. With a dynamic model, based on relatively simple kinetic equations and an additional slow mechanism, e.g. the formation of ethylidyne on the catalyst surface, the qualitative features of this system can be described.

Inthisstudywepresenta measuring method and extensive ex perimentaldataonthegasphaseRTDina mechanically agitated gas-liquid reactor with standard d imensions over a wide range of superficial gas velocities, agitation rates and agitator sizss. The results are mode&d successfully, using the weighed moments method, by a simple RTD model of one mixer in series with a plug flow zone. AR results are correlated in one r&&on, wbicb can be usal for scale-up. 14p a side rule, the following relation for the gas holdup has been obtainesk r (0_88*u, + 5.1* 10-3 (n-rIJ*(%p. es I I + 3_09*10-2* H H with ll#JD = 0.33, II 2 1.5'@n,,, D = H, H = 0.286 m, 0.3 4 DJD 4 0.5, 4.9-10-1