Maximizing high-value chemicals from mixed plastic using different steam-cracker configurations

Patent metadata

Field	Value
Publication number	US-10927315-B2
Application number	US-201716323710-A
Country	US
Kind code	B2
Filing date	Oct 4, 2017
Priority date	Oct 11, 2016
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

A process for producing olefins and aromatics comprising converting plastics to a hydrocarbon product comprising a gas phase and a liquid phase in a pyrolysis unit; separating the hydrocarbon product into a hydrocarbon gas stream comprising the gas phase and a hydrocarbon liquid stream comprising the liquid phase; feeding the hydrocarbon gas stream to a gas steam cracker to produce a gas steam cracker product comprising olefins, wherein an olefins amount in the gas steam cracker product is greater than in the hydrocarbon gas stream; separating the hydrocarbon liquid stream into a first fraction (b.p.<300° C.) and a second fraction (b.p>300° C.); feeding the first fraction to a liquid steam cracker to produce a liquid steam cracker product comprising olefins and aromatics, wherein an olefins amount in the liquid steam cracker product is greater than in the first fraction; and recycling the second fraction to the pyrolysis unit.

First claim

What is claimed is:

1. A process for producing olefins and aromatic hydrocarbons from mixed plastics, the process comprising the steps of:
(a) converting mixed plastics to a hydrocarbon product in a pyrolysis unit, wherein the hydrocarbon product comprises a gas phase and a liquid phase;
(b) separating at least a portion of the hydrocarbon product into a hydrocarbon gas stream and a hydrocarbon liquid stream, wherein the hydrocarbon gas stream comprises at least a portion of the gas phase of the hydrocarbon product, and wherein the hydrocarbon liquid stream comprises at least a portion of the liquid phase of the hydrocarbon product;
(c) feeding at least a portion of the hydrocarbon gas stream to a gas steam cracker to produce a gas steam cracker product stream, wherein the gas steam cracker product stream comprises olefins, and wherein an amount of olefins in the gas steam cracker product stream is greater than an amount of olefins in the hydrocarbon gas stream;
(d) separating at least a portion of the hydrocarbon liquid stream into a first fraction of the hydrocarbon liquid stream and a second fraction of the hydrocarbon liquid stream, wherein the first fraction of the hydrocarbon liquid stream is characterized by a boiling point of less than about 300° C., and wherein the second fraction of the hydrocarbon liquid stream is characterized by a boiling point of equal to or greater than about 300° C.;
(e) feeding at least a portion of the first fraction of the hydrocarbon liquid stream to a liquid steam cracker to produce a liquid steam cracker product stream, wherein the liquid steam cracker product stream comprises olefins and aromatic hydrocarbons, and wherein an amount of olefins in the liquid steam cracker product stream is greater than an amount of olefins in the first fraction of the hydrocarbon liquid stream; and
(f) recycling at least a portion of the second fraction of the hydrocarbon liquid stream to the pyrolysis unit.

2. The process of claim 1 , wherein the olefins of the gas steam cracker product stream comprise light gas olefins, ethylene, propylene, butylene, butadiene, or combinations thereof.

3. The process of claim 1 , wherein the hydrocarbon gas stream further comprises hydrochloric acid (HCl), carbon monoxide (CO), carbon dioxide (CO 2 ), hydrogen (H 2 ), light gas olefins, and saturated hydrocarbons, and wherein the step (c) of feeding at least a portion of the hydrocarbon gas stream to a gas steam cracker further comprises (i) introducing at least a portion of the hydrocarbon gas stream to a scrubber to produce a treated hydrocarbon gas stream, wherein an amount of HCl in the treated hydrocarbon gas stream is less than an amount of HCl in the hydrocarbon gas stream, and wherein at least a portion of the HCl in the hydrocarbon gas stream is removed in the scrubber; (ii) introducing at least a portion of the treated hydrocarbon gas stream to a first separating unit to produce a first saturated hydrocarbons gas stream and a first olefin gas stream, wherein the first olefin gas stream comprises at least a portion of the olefins of the treated hydrocarbon gas stream, wherein the first saturated hydrocarbons gas stream comprises at least a portion of the saturated hydrocarbons of the treated hydrocarbon gas stream, and wherein the first saturated hydrocarbons gas stream is characterized by an olefin content of less than about 1 wt. % olefins, based on the total weight of the first saturated hydrocarbons gas stream; and (iii) feeding at least a portion of the first saturated hydrocarbons gas stream to the gas steam cracker.

4. The process of claim 1 , wherein the step (d) of feeding at least a portion of the first fraction of the hydrocarbon liquid stream to a liquid steam cracker further comprises (i) conveying at least a portion of the first fraction of the hydrocarbon liquid stream and hydrogen to a hydroprocessing unit to produce a treated hydrocarbon liquid stream and a hydroprocessing unit gas product stream, wherein the treated hydrocarbon liquid stream is characterized by a boiling point that is lower than a boiling point of the first fraction of the hydrocarbon liquid stream; wherein the treated hydrocarbon liquid stream is characterized by a chloride amount that is lower than a chloride amount of the first fraction of the hydrocarbon liquid stream; and wherein the treated hydrocarbon liquid stream is characterized by an olefin content that is lower than an olefin content of the first fraction of the hydrocarbon liquid stream; and (ii) feeding at least a portion of the treated hydrocarbon liquid stream to the liquid steam cracker.

5. The process of claim 4 , wherein the treated hydrocarbon liquid stream is characterized by a boiling point of less than about 300° C.

6. The process of claim 4 , wherein the treated hydrocarbon liquid stream comprises one or more chloride compounds in an amount of less than about 10 ppmw chloride, based on the total weight of the treated hydrocarbon liquid stream; and wherein the treated hydrocarbon liquid stream is characterized by an olefin content of less than about 1 wt. % olefins, based on the total weight of the treated hydrocarbon liquid stream.

7. The process of claim 4 , wherein the first fraction of the hydrocarbon liquid stream comprises aromatic compounds, and wherein a portion of the aromatic compounds undergo a ring opening reaction in the hydroprocessing unit to produce non-aromatic compounds.

8. The process of claim 4 , wherein the step (i) of conveying at least a portion of the first fraction of the hydrocarbon liquid stream and hydrogen to a hydroprocessing unit to produce a treated hydrocarbon liquid stream and a hydroprocessing unit gas product stream further comprises (1) recovering a hydroprocessing unit product stream from the hydroprocessing unit, wherein the hydroprocessing unit product stream comprises a gas phase and a liquid phase; and (2) separating the hydroprocessing unit product stream into the treated hydrocarbon liquid stream and the hydroprocessing unit gas product stream, wherein the treated hydrocarbon liquid stream comprises at least a portion of the liquid phase of the hydroprocessing unit product stream; and wherein the hydroprocessing unit gas product stream comprises at least a portion of the gas phase of the hydroprocessing unit product stream.

9. The process of claim 4 , wherein at least a portion of the hydroprocessing unit gas product stream is fed to the gas steam cracker.

10. The process of claim 3 , wherein at least a portion of the gas steam cracker product stream, at least a portion of the liquid steam cracker product stream, at least a portion of the first olefin gas stream, or combinations thereof are introduced to a second separating unit to produce a second olefin gas stream, a second saturated hydrocarbons gas stream, a C 6 -C 8 aromatics stream, a C 9+ aromatics stream, and a non-aromatic heavies stream; wherein the second olefin gas stream comprises ethylene, propylene, butylene, butadiene, or combinations thereof; wherein the second saturated hydrocarbons gas stream comprises methane, ethane, propane, butanes, hydrogen, or combinations thereof; wherein the C 6 -C 8 aromatics stream comprises C 6 -C 8 aromatic hydrocarbons, benzene, toluene, xylenes, ethylbenzene, or combinations thereof; wherein the C 9+ aromatics stream comprises C 9+ aromatic hydrocarbons; and wherein the non-aromatic heavies stream comprises C 5+ hydrocarbons other than C 6+ aromatic hydrocarbons.

11. The process of claim 10 , wherein a second olefin gas stream yield is equal to or greater than about 60%; and wherein a C 6 -C 8 aromatics stream yield is equal to or greater than about 15%.

12. The process of

Assignees

• Sabic Global Technologies Bv

Inventors

• Ramamurthy Krishna Kumar
• Goyheneix Nicolas
• Narayanaswamy Ravichander
• Galan-Sanchez Lara

Classifications

• C10G1/002

  in combination with oil conversion- or refining processes · CPC title

• C10G2400/30

  Aromatics · CPC title

• C10G9/36

  with heated gases or vapours · CPC title

• C10G69/06 Primary

  including at least one step of thermal cracking in the absence of hydrogen · CPC title

• C10G51/06

  plural parallel stages only · CPC title