A process for the in situ attrition and break up of an agglomerating, or agglomerated catalyst to maintain and control the fluidization characteristics of a bed wherein low molecular weight hydrocarbons, oxygen and steam are contacted with the bed to produce hydrogen and carbon monoxide via both partial oxidation and steam reforming reactions. The feeds are injected into the reaction zone with mechanical energy input sufficient to balance the intrinsic rate of agglomeration by fracturing and breaking apart in situ the agglomerated catalyst to maintain the fluidization characteristics of the bed throughout the cycle of operation.