Automation and control of energy efficient fluid catalytic cracking processes for maximizing value added products

Patent metadata

Field	Value
Publication number	US-9765262-B2
Application number	US-201213429047-A
Country	US
Kind code	B2
Filing date	Mar 23, 2012
Priority date	Nov 7, 2006
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

Petroleum oil is catalytically cracked by contacting oil with catalyst mixture consisting of a base cracking catalyst containing an stable Y-type zeolite and small amounts of rare-earth metal oxide, and an additive containing a shape-selective zeolite, in an FCC apparatus having a regeneration zone, a separation zone, and a stripping zone. Production of light-fraction olefins is maximized by applying appropriate process control, monitoring, and optimizing systems. Mathematical process models, including neural networks, statistical models and finite impulse models are used in conjunction with advanced controllers and optimizing routines to calculate optimal settings for various parameters. Process model and historical data to test a predictive system can provide early warning of potential performance degradation and equipment failure in the FCC unit, decreasing overall operating costs and increasing plant safety.

First claim

What is claimed is:

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:
(i) 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 catalyst and unreacted hydrocarbon;
(d) transferring the spent catalyst 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;
(g) separating and collecting the product stream from the spent catalyst and unreacted hydrocarbon in a stripping zone;
(h) withdrawing a stream comprising the product stream and the unreacted hydrocarbon from the stripping zone; and
(i) recycling at least a portion of the product stream from the stream withdrawn from the stripping zone, through a separation zone before sending the recycled portion of the product stream to the reaction zone,
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, in real-time, feed data, products characterization data, and operating conditions;
(iii) selecting, in real-time, one of the predetermined process models based on the monitored, real-time 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.

2. The process of claim 1 , further comprising a microwave generator having a microwave frequency, wherein the operating conditions comprise the reaction zone temperature, the catalyst mixture feed rate, the hydrocarbon feedstock feed rate, the regeneration zone temperature, the recycled regenerated catalyst stream flow rate, the contact time within the reaction zone, the residence time within the regeneration zone, catalyst design, and the microwave frequency.

3. The process of claim 1 , wherein in the stripping zone, a majority of adsorbed material covering the spent catalyst is removed prior to transferring the spent catalyst to the regeneration zone.

4. The process of claim 3 , wherein the majority of adsorbed material covering the spent catalyst is removed by applying microwaves and/or sonic radiation in a dense phase region of the stripper.

5. The process of claim 1 , wherein the catalyst mixture is maintained in a fluidized state.

6. The process of claim 1 , wherein step (e) is performed using heat.

7. The process of claim 1 , wherein step (e) is performed using microwaves.

8. The process of claim 1 , wherein step (e) is performed using sonications.

9. The process of claim 1 , further comprising recycling the unreacted hydrocarbon to the reaction zone.

10. The process of claim 1 , wherein the hydrocarbon feedstock comprises a heavy fraction oil, such that the heavy fraction oil is characterized by having a boiling point, at atmospheric pressure, of about 250° C. and higher.

11. The process of claim 1 , wherein the hydrocarbon feedstock is selected from the group consisting of straight-run gas oil, vacuum gas oil, atmospheric residue, coker gas oil, petroleum oils obtained by hydrofining or hydrotreating atmospheric residue and gas oil, and combinations thereof.

12. The process of claim 1 , further comprising a cracker riser and a medium pore zeolite catalytic component.

13. The process of claim 1 , wherein the reactor within the reaction zone is an up flow-type reactor.

14. The process of claim 1 , further comprising a microwave generator having a microwave frequency, wherein the operating conditions are selected from the group consisting of the reaction zone temperature, the catalyst mixture feed rate, the hydrocarbon feedstock feed rate, the regeneration zone temperature, the recycled regenerated catalyst stream flow rate, the contact time within the reaction zone, the residence time within the regeneration zone, catalyst design, and a microwave frequency.

15. The process of claim 1 , wherein the catalyst comprises:
a base cracking catalyst

Assignees

• Taha Othman A
• Khan M Rashid
• Saudi Arabian Oil Co

Inventors

• Taha Othman A
• Khan M Rashid

Classifications

• C10G11/05

  Crystalline alumino-silicates, e.g. molecular sieves · CPC title

• C10G2400/20

  C2-C4 olefins · CPC title

• G05B13/027

  using neural networks only · CPC title

• C10G2300/1059

  Gasoil having a boiling range of about 330 - 427 °C · CPC title

• G05B17/02

  electric · CPC title