FCC Catalyst section control

Claim 1

In a fluid catalytic cracking process for cracking a hydrocarbon feed stream, wherein said stream is contacted with hot regenerated catalyst in a reactor section maintained under catalytic cracking conditions to form cracked products and spent catalyst contaminated by coke; and wherein said cracked products and spent catalyst are separated in, and recovered from, said reactor section; and wherein said recovered spent catalyst is continuously circulated through a regenerator section operating in the complete CO-burning mode thereby burning said contaminating coke by contact with air and forming hot regenerated catalyst and flue gas at substantially the same temperature, said hot regenerated catalyst having a temperature substantially higher than said spent catalyst, said regenerator section being provided with adjustable means for recycling a portion of hot regenerated catalyst to said recovered spent catalyst; and also with adjustable means for preheating said air; and wherein hot regenerated catalyst is recirculated to said reactor section, the method for controlling the process, whereby improving its adaptive behavior, which comprises: comparing the temperature of the hot regenerated catalyst with a predetermined temperature to obtain a regenerated catalyst temperature deviation; and, adjusting within the regenerator section, the recycle of hot regenerated catalyst to spent catalyst to change the recycle ratio in a direction to reduce said temperature deviation, said recycle ratio being in the range of at least about 0.7 to about 5 before and after said change; and adjusting the air preheat temperature in a direction to reduce said regenerated catalyst temperature deviation.