Absorption recovery processing of light olefins free of carbon dioxide

• US 20080081938A1
• Filed: 09/28/2006
• Published: 04/03/2008
• Est. Priority Date: 09/28/2006
• Status: Abandoned Application

• Current Assignee: UOP Llc (Honeywell International Inc.)
• Original Assignee: UOP Llc (Honeywell International Inc.)
• Inventors: Schultz, Michael A., Wegerer, David A., Lechnick, William J., Towler, Gavin P., Brady, John P.
• Application Number:
  US11/541,200
• Publication Number:
  US 20080081938A1
• Time in Patent Office: Days
• US Class Current: 585/648
• CPC Class Codes: B01D 2256/24 Hydrocarbons
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/1475 Removing carbon dioxide
• CPC Class Codes: B01D 53/77 Liquid phase processes
• CPC Class Codes: C07C 11/04 Ethylene
• CPC Class Codes: C07C 11/06 Propene
• CPC Class Codes: C07C 7/005 Processes comprising at least two steps in series
• CPC Class Codes: C07C 7/11 by absorption, i.e. purification or separation of gaseous hydrocarbons with the aid of liquids
• CPC Class Codes: C10G 2400/20 C2-C4 olefins
• CPC Class Codes: C10G 9/206 controlling or regulating the tube furnaces
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2
• CPC Class Codes: Y02P 20/50 Improvements relating to the production of bulk chemicals
• CPC Class Codes: Y02P 20/52 using catalysts, e.g. selective catalysts
• CPC Class Codes: Y02P 30/40 Ethylene production

Abstract

Processing schemes and arrangements for the amine treatment of high olefin content (e.g., ethylene-rich) carbon dioxide-containing streams such as for the effective separation and removal of carbon dioxide therefrom are provided. Corresponding or associated processing schemes and arrangements for the catalytic cracking of a heavy hydrocarbon feedstock and obtaining light olefins substantially free of carbon dioxide via absorption-based product recovery are also provided.

Claims

1. A process for catalytic cracking a heavy hydrocarbon feedstock and obtaining light olefins substantially free of carbon dioxide, the process comprising:

contacting a heavy hydrocarbon feedstock with a hydrocarbon cracking catalyst in a fluidized reactor zone to produce a hydrocarbon effluent comprising a range of hydrocarbon products, including light olefins, and a quantity of carbon dioxide;

separating the hydrocarbon effluent in a hydrocarbon separation system to form a separator liquid stream and a separator vapor stream, the separator liquid stream comprising C₃+ hydrocarbons substantially free of carbon dioxide, the separator vapor stream comprising C₃−

hydrocarbons and at least a portion of the quantity of carbon dioxide;

treating the separator vapor stream in an absorption zone to form an absorption zone effluent stream comprising C₂−

hydrocarbons and at least a portion of the quantity of carbon dioxide; and

treating the absorption zone effluent stream in an amine treatment section with an amine absorption solvent at treatment conditions effective to absorb a significant portion of the carbon dioxide from the contacted portion of the absorption zone effluent stream and to form a hydrocarbon-containing, ethylene-rich process stream substantially free of carbon dioxide.

2. The process of claim 1 wherein said contacting of the heavy hydrocarbon feedstock with a hydrocarbon cracking catalyst comprises contacting the heavy hydrocarbon feedstock with a blended catalyst comprising regenerated catalyst and coked catalyst in a fluidized reactor zone at hydrocarbon cracking reaction conditions to produce a cracked stream containing hydrocarbon products including light olefins and a quantity of carbon dioxide, said catalyst having a catalyst composition including a first component comprising a large pore molecular sieve and a second component comprising a zeolite with no greater than medium pore size, said zeolite with no greater than medium pore size comprising at least 1.0 wt. % of the catalyst composition.

3. The process of claim 1 wherein said treating of the absorption zone effluent stream in the amine treatment section with the amine absorption solvent comprises:

contacting at least a portion of the absorption zone effluent stream in an absorption zone with the amine absorption solvent and at contact conditions effective to absorb a significant portion of the carbon dioxide from the contacted portion of the absorption zone effluent stream and to form a hydrocarbon-containing process stream substantially free of carbon dioxide and a carbon dioxide-rich amine absorption solvent-containing process stream;

processing at least a portion of the carbon dioxide-rich amine absorption solvent-containing process stream in a first stripping zone at first stripping conditions effective to strip at least a portion of hydrocarbons remaining in the carbon dioxide-rich amine absorption solvent-containing process stream to form a first process stream comprising stripped hydrocarbons and a second process stream comprising carbon dioxide and amine absorption solvent; and

processing at least a portion of the second process stream in a second stripping zone at second stripping conditions effective to strip at least a portion of the carbon dioxide from the second process stream to form a carbon dioxide purge stream and an amine stream.

4. The process of claim 1 wherein the treating of the separator vapor stream in an absorption zone to form an absorption zone effluent stream comprises:

contacting the separator vapor stream with a first absorbent solvent in a primary absorber to form a process stream comprising C₃+ hydrocarbons in the first absorbent solvent and an overhead stream comprising C₂−

materials.

5. The process of claim 4 additionally comprising:

separating C₂−

materials from the separator liquid stream to form a C₃+ process stream;

separating C₅+ materials from the C₃+ process stream to form a first product process stream comprising C₅+ materials and a second product process stream comprising C₃ and C₄ hydrocarbons;

separating at least a portion of the C₃ hydrocarbons from at least a portion of the C₄ hydrocarbons of the second product process stream to form a C₃-containing process stream; and

separating propylene from the C₃-containing process stream.

6. The process of claim 5 additionally comprising:

introducing at least a portion of the first product process stream comprising C₅+ materials into the primary absorber as the first absorbent solvent.

7. The process of claim 1 wherein at least a portion of the hydrocarbon-containing, ethylene-rich process stream substantially free of carbon dioxide comprises a quantity of acetylene, the process additionally comprising:

converting at least a portion of the quantity of acetylene to form an additionally ethylene-enriched process stream; and

separating ethylene from the additionally ethylene-enriched process stream.

8. The process of claim 1 additionally comprising:

separating propylene from the separator liquid stream.

9. The process of claim 8 wherein said separating of propylene from the separator liquid stream comprises:

separating C₂−

materials from the separator liquid stream to form a process stream comprising C₃+ hydrocarbons;

separating C₅+ materials from the process stream comprising C₃+ hydrocarbons to form a first product process stream comprising C₅+ materials and a second product process stream comprising C₃ and C₄ hydrocarbons;

separating at least a portion of the C₃ hydrocarbons from at least a portion of the C₄ hydrocarbons of the second product process stream to form a C₃-containing process stream; and

separating propylene from the C₃-containing process stream.

10. A process for catalytic cracking a heavy hydrocarbon feedstock and obtaining light olefins substantially free of carbon dioxide, said process comprising:

contacting a heavy hydrocarbon feedstock with a blended catalyst comprising regenerated catalyst and coked catalyst in a fluidized reactor zone at hydrocarbon cracking reaction conditions to produce a cracked stream containing hydrocarbon products including light olefins and a quantity of carbon dioxide, said catalyst having a catalyst composition including a first component comprising a large pore molecular sieve and a second component comprising a zeolite with no greater than medium pore size, said zeolite with no greater than medium pore size comprising at least 1.0 wt. % of the catalyst composition;

separating the hydrocarbon products in a hydrocarbon separation section to form a high pressure separator liquid stream and a high pressure separator vapor stream, the high pressure separator liquid stream comprising C₃+ hydrocarbons substantially free of carbon dioxide, the high pressure separator vapor stream comprising C₃−

hydrocarbons and at least a portion of the quantity of carbon dioxide;

introducing the high pressure separator vapor stream into an absorption zone to form an absorption zone effluent stream comprising C₂−

hydrocarbons and at least a portion of the quantity of carbon dioxide; and

treating the absorption zone effluent stream in an amine treatment section with an amine absorption solvent at treatment conditions effective to absorb a significant portion of the carbon dioxide from the contacted portion of the absorption zone effluent stream to form a hydrocarbon-containing, ethylene-rich process stream substantially free of carbon dioxide.

11. The process of claim 10 wherein said treating of the absorption zone effluent stream in the amine treatment section with the amine absorption solvent comprises:

contacting at least a portion of the absorption zone effluent stream in an absorption zone with the amine absorption solvent and at contact conditions effective to absorb a significant portion of the carbon dioxide from the contacted portion of the absorption zone effluent stream and to form a hydrocarbon-containing process stream substantially free of carbon dioxide and a carbon dioxide-rich amine absorption solvent-containing process stream;

processing at least a portion of the carbon dioxide-rich amine absorption solvent-containing process stream in a first stripping zone at first stripping conditions effective to strip at least a portion of hydrocarbons remaining in the carbon dioxide-rich amine absorption solvent-containing process stream to form a first process stream comprising stripped hydrocarbons and a second process stream comprising carbon dioxide and amine absorption solvent; and

processing at least a portion of the second process stream in a second stripping zone at second stripping conditions effective to strip at least a portion of the carbon dioxide from the second process stream to form a carbon dioxide purge stream and an amine stream.

12. The process of claim 10 wherein the treating of the separator vapor stream in an absorption zone to form an absorption zone effluent stream comprises:

contacting the separator vapor stream with a first absorbent solvent in a primary absorber to form a return process stream comprising C₃+ hydrocarbons in the first absorbent solvent and an overhead stream comprising C₂−

materials.

13. The process of claim 12 additionally comprising:

separating C₂−

materials from the separator liquid stream to form a C₃+ process stream;

separating C₅+ materials from the C₃+ process stream to form a first product process stream comprising C₅+ materials and a second product process stream comprising C₃ and C₄ hydrocarbons;

separating at least a portion of the C₃ hydrocarbons from at least a portion of the C₄ hydrocarbons of the second product process stream to form a C₃-containing process stream; and

separating propylene from the C₃-containing process stream.

14. The process of claim 13 additionally comprising:

introducing at least a portion of the first product process stream comprising C₅+ materials into the primary absorber as the first absorbent solvent.

15. The process of claim 10 additionally comprising:

separating C₂ hydrocarbons from the ethylene-rich process stream to form a C₂-containing process stream, the C₂-containing process stream comprising a quantity of acetylene;

converting at least a portion of the quantity of acetylene if the C₂-containing process stream to form an additionally ethylene-enriched process stream; and

separating ethylene from the additionally ethylene-enriched process stream.

16. The process of claim 10 additionally comprising:

separating propylene from the separator liquid stream.

17. The process of claim 16 wherein said separating of propylene from the separator liquid stream comprises:

separating C₂−

materials from the separator liquid stream to form a process stream comprising C₃+ hydrocarbons;

separating C₅+ materials from the process stream comprising C₃+ hydrocarbons to form a first product process stream comprising C₅+ materials and a second product process stream comprising C₃ and C₄ hydrocarbons;

separating at least a portion of the C₃ hydrocarbons from at least a portion of the C₄ hydrocarbons of the second product process stream to form a C₃-containing process stream; and

separating propylene from the C₃-containing process stream.

18. The process of claim 17 wherein the second process stream additionally comprises a quantity of hydrogen sulfide, the process additionally comprising:

treating at least a portion of the second process stream to reduce the quantity of hydrogen sulfide therein prior to said separating of at least a portion of the C₃ hydrocarbons from at least a portion of the C₄ hydrocarbons of the second product process stream.

19. The process of claim 17 wherein the second product process stream additionally comprises a quantity of mercaptan materials, the process additionally comprising:

removing at least a portion of the quantity of mercaptan materials from at least a portion of the second product process stream prior to said separating of at least a portion of the C₃ hydrocarbons from at least a portion of the C₄ hydrocarbons of the second product process stream.

20. A system for catalytically cracking a heavy hydrocarbon feedstock to obtain light olefins, the system comprising:

a fluidized reactor zone wherein the heavy hydrocarbon feedstock contacts a blended catalyst comprising regenerated catalyst and coked catalyst at hydrocarbon cracking reaction conditions to produce a cracked stream containing hydrocarbon products including light olefins and a quantity of carbon dioxide,

a separator to separate the cracked stream to form a high pressure separator liquid stream comprising C₃+ hydrocarbons and a high pressure separator vapor stream comprising C₃−

hydrocarbons and at least a portion of the quantity of carbon dioxide,

an absorption zone to absorb C₃+ hydrocarbons from the high pressure separator vapor stream to form an absorption zone effluent stream comprising C₂−

hydrocarbons, including ethylene, and at least a portion of the quantity of carbon dioxide; and

an amine treatment section to treat the absorption zone effluent stream by contacting at least a portion of the absorption zone effluent stream with an amine absorption solvent at contact conditions effective to absorb a significant portion of the carbon dioxide from the contacted portion of the absorption zone effluent stream and to form a hydrocarbon-containing, ethylene-rich process stream substantially free of carbon dioxide and a carbon dioxide-rich amine absorption solvent-containing process stream.