Patent Document ID: 20120193269
Application ID: 13429047
Patent Flag: 0

Claim One:
1. A process for the fluid catalytic cracking of a hydrocarbon feedstock comprising the steps of: (a) reacting the hydrocarbon feedstock with a catalyst mixture, said catalyst mixture comprising between about 60-90% by weight of a base cracking catalyst and between about 5-40% by weight of an additive comprising a shape selective zeolite, in a continuous fashion in a reaction zone under reaction conditions to form a produced mixture, the produced mixture comprising a product stream and a spent stream, the catalyst mixture comprising a base cracking catalyst, an ultra-stable Y-type zeolite, an unreacted catalyst stream, and a regenerated catalyst stream, the catalyst mixture having a catalyst mixture feed rate, the hydrocarbon feedstock having a hydrocarbon feedstock feed rate, the produced mixture having a produced mixture flow rate, wherein the reaction zone comprises: flow rate sensors that are operable to monitor the hydrocarbon feedstock feed rate, the catalyst mixture feed rate, and the produced mixture flow rate; (ii) temperature sensors that are operable to measure a reaction zone temperature; (iii) control valves that are in communication with a process control system such that the process control system is operable to modify an amount of closure of the control valves such that the hydrocarbon feedstock feed rate, the catalyst mixture feed rate and the produced mixture flow rate are subject to manipulation; and (iv) a reactor; wherein the reaction conditions comprise: (i) an operating temperature; and (ii) a contact time of approximately 0.1 to 1 seconds; (b) separating the produced mixture into the product stream and the spent stream, the spent stream comprising spent catalyst and unreacted hydrocarbon; (c) separating the spent stream into spent catalysts and unreacted hydrocarbon; (d) transferring the spent catalysts to a regeneration zone, wherein the regeneration zone comprises a catalyst regenerator, the regeneration zone having a regeneration zone temperature; (e) regenerating the spent catalyst in the regeneration zone using an oxidation treatment to produce the regenerated catalyst stream, the regenerated catalyst stream having decreased amounts of adsorbed material as compared to the spent catalyst, the spent catalyst having a spent catalyst flow rate, and the spent catalyst having a residence time within the regeneration zone; (f) recycling in a continuous fashion the regenerated catalyst stream into the reaction zone, the regenerated catalyst stream having a recycled regenerated catalyst flow rate; wherein the process has operating conditions, the operating conditions are operable to be controlled by the process control system, wherein the process control system has control parameters, the control parameters comprising the steps of: (i) obtaining predetermined process models that are operable to simulate operating conditions and produce simulated propylene production and simulated energy usage for the fluid catalytic cracking unit, wherein each predetermined process model is developed to simulate the fluid catalytic cracking unit for a specific range of the operating conditions; (ii) monitoring feed data, products characterization data, and operating conditions; (iii) selecting one of the predetermined process models based on the monitored feed data, monitored products characterization data and monitored operating conditions; (iv) calculating simulated-optimized-operating conditions using the selected predetermined process model; (v) adjusting the operating conditions to correspond with the simulated-optimized-operating-conditions; (vi) measuring a propylene concentration in the product stream; (vii) measuring energy usage of the fluid catalytic cracking unit; (viii) comparing the propylene concentration with a predetermined propylene concentration range to determine whether the propylene concentration falls within the predetermined propylene concentration range; (ix) comparing the energy usage of the fluid catalytic cracking unit with a predetermined energy usage range to determine whether the energy usage falls within the predetermined energy usage range; and (x) adjusting the operating conditions until propylene concentration falls within the predetermined minimum propylene specification to yield optimized propylene production, wherein optimized propylene production is determined by maximizing a ratio of propylene production over energy usage, wherein energy usage is the energy consumed by the fluid catalytic cracking unit.