System and process for steam cracking and PFO treatment integrating selective hydrogenation and FCC

Patent metadata

Field	Value
Publication number	US-11220637-B2
Application number	US-201916668946-A
Country	US
Kind code	B2
Filing date	Oct 30, 2019
Priority date	Oct 30, 2019
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

A process for treatment of PFO from a steam cracking zone includes selectively hydrogenating PFO or a portion thereof for conversion of polyaromatics compounds contained in the PFO into aromatic compounds with one benzene ring to produce a selectively hydrogenated stream. The selectively hydrogenated stream is reacted in a fluid catalytic cracking reactor for selective ring opening and dealkylation to produce fluid catalytic cracking including light cycle oil. The light cycle oil is separated into BTX compounds. Optionally the PFO is separated into a first stream containing C9+ aromatics compounds with one benzene ring, and a second stream containing C10+ aromatic compounds, whereby the first stream containing C9+ aromatics compounds with one benzene ring is passed to the fluid catalytic cracking reactor, and the feed to the selective hydrogenation step comprises all or a portion of the second stream containing C10+ aromatic compounds.

First claim

The invention claimed is:

1. A process for treatment of PFO from a steam cracking zone that produces light olefins and PFO from one or more steam cracking feeds, the process comprising:
optionally separating the PFO into at least a first stream containing C9+ aromatics compounds with one benzene ring, and a second stream containing C10+ aromatic compounds;
selectively hydrogenating all or a portion of the PFO, or all or a portion of the second stream containing C10+ aromatics compounds, using catalysts and conditions, including hydrogen, effective for conversion of polyaromatics compounds contained in the PFO into aromatic compounds with one benzene ring to produce selectively hydrogenated effluents;
reacting all or a portion of the selectively hydrogenated effluents and optionally all or a portion of the first stream containing C9+ aromatics compounds with one benzene ring, by fluid catalytic cracking using catalysts and conditions effective for ring opening and dealkylation to produce fluid catalytic cracking reaction products including light cycle oil;
separating at least a portion of the light cycle oil into BTX compounds.

2. The process as in claim 1 , wherein the PFO is obtained from steam cracking of treated crude oil or other treated heavy oil feeds, and comprises at least 40 wt % of polyaromatics having three or more aromatic rings including triaromatics, naphtheno-triaromatics, tetraaromatics, penta-aromatics and heavier poly-aromatics including asphaltenes and coke.

3. The process as in claim 1 , wherein all or a portion of C20+ polyaromatic compounds are separated from the PFO or from the second stream, prior to selectively hydrogenating all or a portion of the PFO or all or a portion of the second stream containing C10+ aromatics compounds.

4. The process as in claim 1 , wherein the PFO is separated into the first stream, the second stream, and a third stream containing C20+ polyaromatic compounds, and wherein the second stream contains C10+ compounds with no less than 2 and up to 6 benzene rings.

5. The process as in claim 1 , wherein all or a portion of C9+ aromatics with one benzene ring are selectively hydrogenated with all or a portion of the PFO or all or a portion of the second stream containing C10+ aromatics compounds.

6. The process as in claim 1 , wherein the PFO is separated into at least the first stream and the second stream, and wherein all or a portion of the first stream containing C9+ aromatics compounds with one benzene ring bypasses selective hydrogenating and is subjected to fluid catalytic cracking with the selectively hydrogenated effluents.

7. The process as in claim 1 , wherein the PFO stream or the second stream contains C20+ polyaromatic compounds, and wherein:
selective hydrogenating occurs in the presence of a selective hydrogenating catalyst, and wherein selective hydrogenating conditions comprise a reaction temperature (° C.) in the range of about 250-500, a reaction pressure (hydrogen partial pressure, kg/cm 2 ) in the range of about 10-70, a hydrogen feed rate (standard liters per liter of hydrocarbon feed, SLt/Lt) in the range of about 30-5000, and a LHSV in the range of about 0.1-20; and
fluid catalytic cracking reactions occur in the presence of fluid catalytic cracking catalyst,
in a riser reactor configuration under reaction conditions comprising a reaction temperature (° C.) in the range of about 480-600, a reaction pressure (kg/cm 2 ) in the range of about 1-10, a contact time (seconds) of from about 1.5-10, and a catalyst-to-feed ratio (weight) of about 1:1 to 15:1; or
in a downflow reactor configuration in the presence of fluid catalytic cracking catalyst, and under reaction conditions comprising a reaction temperature (° C.) in the range of about 450-600, a reaction pressure (kg/cm 2 ) in the range of about 1-10, a contact time (seconds) of from about 0.2-30, and a catalyst-to-feed ratio (weight) of about 1:1 to 40:1.

8. The process as in claim 1 , wherein all or a portion of C20+ polyaromatic compounds are removed prior to selective hydrogenation, and wherein:
selective hydrogenating occurs in the presence of a selective hydrogenating catalyst, and wherein selective hydrogenating conditions comprise a reaction temperature (° C.) in the range of about 250-480, a reaction pressure (hydrogen partial pressure, kg/cm 2 ) in the range of about 10-50, a hydrogen feed rate (standard liters per liter of hydrocarbon feed, SLt/Lt) in the range of about 30-4000, and a LHSV in the range of about 0.1-20; and
fluid catalytic cracking reactions occur in the presence of fluid catalytic cracking catalyst,
in a riser reactor configuration under reaction conditions comprising a reaction temperature (° C.) in the range of about 480-600, a reaction pressure (kg/cm 2 ) in the range of about 1-10, a contact time (seconds) of from about 1.5-10, and a catalyst-to-feed ratio (weight) of about 1:1 to 15:1; or
in a downflow reactor configuration in the presence of fluid catalytic cracking catalyst, and under reaction conditions comprising a reaction temperature (° C.) in the range of about 450-600, a reaction pressure (kg/cm 2 ) in the range of about 1-10, a contact time (seconds) of from about 0.2-30, and a catalyst-to-feed ratio (weight) of about 1:1 to 40:1.

9. The process as in claim 1 , wherein light gases from selective hydrogenating and/or fluid catalytic cracking reactions are treated and one or more LPG streams are recovered, wherein the one or more LPG streams are passed to the steam cracking zone as additional steam cracking feed.

10. The process as in claim 1 , wherein the selectively hydrogenated effluents are separated into an LPG stream that is treated and passed to the steam cracking zone, and a stream containing one-ring C9+ hydrocarbon compounds that is passed to fluid catalytic cracking reactions as all or a portion of the selectively hydrogenated effluents.

11. The process as in claim 1 , wherein separating at least a portion of the light cycle oil into BTX compounds further comprises separating C9 aromatic compounds, and wherein the process further comprises transalkylating the separated C9 aromatic compounds to produce a transalkylated effluent containing additional BTX compounds.

12. The process as in claim 11 , wherein light gases from transalkylating are treated and one or more LPG streams are recovered, and wherein the one or more LPG streams are passed to the steam cracking zone as additional steam cracking feed.

13. The process as in claim 11 , further comprising separating naphtha-range hydrocarbon compounds from the transalkylated effluent prior to separation into BTX compounds, and passing all or a portion of said naphtha-range hydrocarbon compounds to the steam cracking zone as additional steam cracking feed.

14. The process as in claim 11 , further comprising recovering a raffinate stream comprising non-aromatic compounds from the transalkylated effluent, and passing all or a portion of said raffinate stream to the steam cracking zone as additional steam cracking feed.

15. The process as in claim 14 , wherein recovering a raffinate stream is by aromatics extraction to separate the light cycle oil into the raffinate stream and an extract stream comprising aromatic compounds, and wherein the extract stream is separated into the BTX compounds.

16. The process as in claim 1 , wherein separating the light cycle oil into BTX compounds further comprises separating C10+ compounds from the light cycle oil.

17. The process as in claim 16 , wherein at least a portion of the separated C10+ compounds are subjected to fluid cataly

Assignees

• Saudi Arabian Oil Co

Inventors

• Xu Qi
• Abudawoud Raed

Classifications

• C10G2300/4012

  Pressure · CPC title

• C10G2300/1096

  Aromatics or polyaromatics · CPC title

• C10G47/28

  according to the "moving-bed" technique · CPC title

• C10G69/123

  alkylation · CPC title

• C10G2300/4081

  Recycling aspects · CPC title