Patent ID: 9701914
Date: 2017-07-11
CPC Classifications: B01J,C10G,G05D

Claim:
1. A process for the production of propylene by the fluid catalytic cracking of petroleum oil feedstock, the process comprising the steps of: contacting the oil feedstock with a cracking catalyst mixture, the cracking catalyst mixture comprising: reacting the cracking catalyst mixture and oil feedstock in a reaction zone of a down-flow type fluid catalytic cracking apparatus having a regeneration zone, a first separation zone, a stripping zone, and a catalyst injection system, said fluid catalytic cracking apparatus maintained at a temperature of between 500° C. and 650° C. and a contact time of approximately 0.05 to 3.0 seconds, to obtain a mixture of a propylene product stream, unreacted oil feedstock and spent catalyst, wherein the propylene product stream comprises an increased amount of propylene as compared to an amount of propylene in the feed stream; wherein the catalyst/oil ratio in the fluid catalytic cracking apparatus is between 10 to 50 wt/wt; wherein the catalyst injection system comprises at least one catalyst injection apparatus, at least one sensor adapted to determine the propylene product stream composition, and a controller coupled to the system, wherein the catalyst injection system controls catalyst injection in response to a signal from the at least sensor; wherein the addition of oil feedstock and catalyst to the reaction zone is controlled by a process control; and separating and collecting the propylene product stream from the spent catalyst and unreacted oil feedstock in the stripping zone; regenerating spent catalyst in the regeneration zone; withdrawing a stream comprising the propylene product stream and the unreacted oil feedstock from the stripping zone; and recycling at least a portion of the propylene product stream from the stream withdrawn from the stripping zone, through a second separation zone before sending the recycled portion of the propylene product stream to the reaction zone, wherein the process control comprises the steps of: