Patent ID: 6143915
Filing Date: 2000-11-07
Classification: B01J,C07C,Y02P

Abstract:
A process for the ammoxidation of propylene to produce acrylonitrile, the process comprising:contacting reactants comprising propylene and ammonia in a dense phase reaction zone with an ammoxidation catalyst at propylene ammoxidation conditions;maintaining a dense bed of catalyst in the dense phase reaction zone at fluidized conditions including a catalyst hold up of at least 25% at a superficial gas velocity that does not exceed 1 m/s;cooling the dense bed by indirect heat exchange with a cooling fluid;passing an intermediate reaction stream from an outlet end of the dense phase reaction zone into a circulating fluidized bed (CFB) reaction zone along with an oxygen source, said intermediate reaction stream comprising unreacted propene;continuing the ammoxidation of propene as the intermediate reaction mixture passes through the CFB reaction zone;maintaining a catalyst hold up not greater than 15% in the CFB and a superficial gas velocity of at least 3 m/s in the CFB;separating catalyst from the reacted stream that exits the CFB reaction zone; andrecovering a reacted stream containing acrylonitrile from the CFB.