In a catalytic reactor and a catalytic process, relative rotation is established between a honeycomb-like catalyst body (17) and feed and withdrawal means (11-14) for flushing and regenerating medium flows, and for the flow of material to be subjected to a catalysed reaction, In this manner, the different parts of the honeycomb-like body (17) will be successivle subjected to the different flows during each revolution. By adapting the rotational speed and the sector extent and also the gas throughflow rate for each individual zone to the flushing and regenerating medium flows and to the material flow, the time during which the catalyst is exposed to the different flows can be optimised for a given catalytic process.