DUAL RISER CATALYTIC CRACKER FOR INCREASED LIGHT OLEFIN YIELD

• US 20130158326A1
• Filed: 12/14/2011
• Published: 06/20/2013
• Est. Priority Date: 12/14/2011
• Status: Active Grant

• Current Assignee: UOP Llc (Honeywell International Inc.)
• Original Assignee: UOP Llc (Honeywell International Inc.)
• Inventors: Wegerer, David A., Hedrick, Brian W., Myers, Daniel N., Palmas, Paolo, Leonard, Laura E., Fei, Zhihao
• Granted Patent: US 9,238,600 B2
• Time in Patent Office: Days
• US Class Current: 585/634
• CPC Class Codes: C07C 11/04 Ethylene
• CPC Class Codes: C07C 11/06 Propene
• CPC Class Codes: C07C 2521/04 Alumina
• CPC Class Codes: C07C 2521/08 Silica
• CPC Class Codes: C07C 2521/16 Clays or other mineral silicates
• CPC Class Codes: C07C 2529/40 of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11
• CPC Class Codes: C07C 2529/50 of the eroionite or offretite type, e.g. zeolite T
• CPC Class Codes: C07C 2529/65 of the ferrierite type, e.g. types ZSM-21, ZSM-35 or ZSM-38
• CPC Class Codes: C07C 4/06 Catalytic processes C07C4/025 takes precedence
• CPC Class Codes: C10G 11/05 Crystalline alumino-silicates, e.g. molecular sieves
• CPC Class Codes: C10G 11/18 according to the "fluidised-bed" technique
• CPC Class Codes: C10G 2400/20 C2-C4 olefins
• CPC Class Codes: C10G 51/026 only catalytic cracking steps
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts
• CPC Class Codes: Y02P 20/584 Recycling of catalysts

Abstract

A process for improving the yield of ethylene and propylene from a light naphtha feedstock includes obtaining light naphtha feedstock from a primary cracking zone having a cracking catalyst. The light naphtha feedstock is contacted with an olefin catalyst in an olefin producing zone to produce an ethylene- and propylene-rich stream. After reacting with the olefin catalyst, the ethylene- and propylene-rich stream is separated from the olefin catalyst from in a separator zone. At least a portion of the olefin catalyst is regenerated by combusting coke deposited on a surface of the olefin catalyst in an oxygen-containing environment, and at least a portion of the olefin catalyst is heated. These portions could be the same one or they could be different. In some embodiments, at least a portion of the olefin catalyst could be neither regenerated nor heated. The olefin catalyst is returned to the olefin producing zone.

Claims

1. A process for improving the yield of ethylene and propylene from a light naphtha feedstock, comprising:

obtaining light naphtha feedstock from a primary cracking zone comprising a cracking catalyst;

contacting the light naphtha feedstock with an olefin catalyst in an olefin producing zone to produce an ethylene- and propylene-rich stream;

separating the olefin catalyst from the ethylene- and propylene-rich stream in a separator zone;

regenerating at least a portion of the olefin catalyst by combusting coke deposited on a surface of the olefin catalyst in an oxygen-containing environment;

heating at least a portion of the olefin catalyst with a stream of hot combustion gas; and

returning the olefin catalyst to the olefin producing zone.

2. The process of claim 1 wherein the primary cracking zone is a fluidized bed catalytic cracking zone, a resid fluidized bed catalytic cracking zone or a fluidized bed catalytic cracking zone optimized to produce olefins.

3. The process of claim 1 wherein at least a portion of the hot combustion gas is flue gas from a catalyst regenerator for the cracking catalyst.

4. The process of claim 1 wherein at least a portion of the hot combustion gas is from an auxiliary heater burning an auxiliary fuel, or oxygen or both.

5. The process of claim 4 wherein at least a portion of the hot combustion gas is supplied to the catalyst regenerator for the cracking catalyst, or the catalyst regenerator for the olefin catalyst, or both after the heating step.

6. The process of claim 1 wherein the heating step further comprises utilizing a heat exchanger to transfer heat from the hot combustion gases to the olefin catalyst.

7. The process of claim 1 further comprising separating C₄+ naphtha from the ethylene- and propylene-rich stream and recycling the C₄+ olefins to the olefin-producing zone.

8. The process of claim 1 wherein the cracking catalyst comprises zeolite Y and the olefin catalyst comprises ZSM-5.

9. The process of claim 1 wherein at least a portion of the olefin catalyst is returned to the olefin producing zone without heating or regenerating.

10. A process for improving the yield of ethylene and propylene from a light naphtha feedstock, comprising:

obtaining light naphtha feedstock from a primary cracking zone comprising a cracking catalyst;

contacting the light naphtha feedstock with an olefin catalyst in an olefin producing zone to produce an ethylene- and propylene-rich stream;

separating the olefin catalyst from the ethylene- and propylene-rich stream in a separator zone;

regenerating at least a portion of the olefin catalyst by combusting coke deposited on a surface of the olefin catalyst in an oxygen-containing environment;

directly heating at least a portion of the olefin catalyst with a stream of hot combustion gas; and

returning the olefin catalyst to the olefin producing zone.

11. The process of claim 10 wherein the olefin catalyst is directly heated with the hot combustion gas simultaneously with regenerating the olefin catalyst.

12. The process of claim 10 wherein at least a portion of the hot combustion gas is flue gas from a catalyst regenerator for the cracking catalyst.

13. The process of claim 10 wherein at least a portion of the hot combustion gas is from an auxiliary heater burning an auxiliary fuel, or oxygen or both.

14. The process of claim 10 further comprising combusting CO to provide additional heat while directly heating at least the portion of the olefin catalyst with the stream of hot combustion gas.

15. The process of claim 10 wherein the stream of hot combustion gases comprises at least a portion of flue gas from a catalyst regenerator for the cracking catalyst.

16. The process of claim 10 wherein at least a portion of the olefin catalyst is returned to the olefin producing zone without heating or regenerating.

17. The process of claim 10 further comprising heating the light naphtha feedstock with hot flue gas from the catalyst regenerator for the olefin catalyst.

18. An apparatus for processing light naphtha from a catalytic cracking zone to produce ethylene and propylene, the apparatus comprising:

a catalytic cracking zone comprising a cracking catalyst;

a first separator zone at the exit of the catalytic cracking zone for separation of the catalytic cracking zone effluent from the cracking catalyst;

a regenerator for the cracking catalyst, wherein coke deposited on the cracking catalyst is removed by combustion, the regenerator for the cracking catalyst in fluid communication with the first separator zone, and the regenerator for the cracking catalyst in communication with the entrance of the catalytic cracking zone;

an olefin cracking zone comprising an olefin catalyst;

a second separator at the exit of the olefin cracking zone for separation of the olefin cracking zone effluent from the olefin catalyst;

a regenerator for the olefin catalyst, wherein coke deposited on the olefin catalyst is removed by combustion, the regenerator for the olefin catalyst in fluid communication with the second separator zone, and the regenerator for the olefin catalyst in fluid communication with the entrance of the olefin cracking zone; and

a heater in fluid communication with a source of hot combustion gases to heat at least a portion of the olefin catalyst prior to addition to the olefin cracking zone.

19. The apparatus of claim 18 wherein the heater is positioned between the second separator and the entrance of the olefin cracking zone, or between the second separator and the regenerator for the olefin catalyst, or between the regenerator for the olefin catalyst and the entrance of the olefin cracking zone.

20. The process of claim 18 further comprising a conduit in fluid communication with the second separator zone and the entrance of the olefin cracking zone.