TWO STAGE HYDROPROCESSING WITH DIVIDED WALL COLUMN FRACTIONATOR

• US 20120004478A1
• Filed: 06/24/2011
• Published: 01/05/2012
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: ExxonMobil Research & Engineering Company (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Research & Engineering Company (Exxon Mobil Corporation)
• Inventors: Umansky, Benjamin S., Lewis, William E., Dougherty, Richard C., Hayes, Michael A.
• Granted Patent: US 8,591,726 B2
• Time in Patent Office: Days
• US Class Current: 585/240
• CPC Class Codes: B01D 3/141 where at least one distillation column contains at least one dividing wall
• CPC Class Codes: B01D 3/143 by two or more of a fractionation, separation or rectification step
• CPC Class Codes: C10G 2300/1011 Biomass
• CPC Class Codes: C10G 2300/1055 Diesel having a boiling range of about 230 - 330 °C
• CPC Class Codes: C10G 2300/202 Heteroatoms content, i.e. S, N, O, P
• CPC Class Codes: C10G 2300/301 Boiling range
• CPC Class Codes: C10G 2300/304 Pour point, cloud point, cold flow properties
• CPC Class Codes: C10G 2300/4006 Temperature
• CPC Class Codes: C10G 2300/4012 Pressure
• CPC Class Codes: C10G 2300/4018 Spatial velocity, e.g. LHSV, WHSV
• CPC Class Codes: C10G 2400/04 Diesel oil
• CPC Class Codes: C10G 65/12 including cracking steps and other hydrotreatment steps
• CPC Class Codes: C10L 1/08 for compression ignition
• CPC Class Codes: Y02P 30/20 using bio-feedstock

Abstract

A divided wall column can allow for fractionation of multiple streams while maintaining separate product qualities. Effluents from multiple stages of a reaction system can be processed in a single divided wall column. The divided wall column can produce multiple cuts from each separated area, as well as at least one output from a common area. At least one reaction stage can advantageously have a continuous liquid phase environment.

Claims

1. A method for producing low sulfur distillate products, comprising:

hydrotreating a feedstock under first effective hydrotreating conditions;

fractionating the hydrotreated feedstock in a first volume of a divided wall column fractionator to produce at least a first product fraction, a first bottoms fraction, and a first common fraction that is passed to an upper undivided volume of the fractionator;

dissolving hydrogen in at least a portion of the first bottoms fraction to approximately the solubility limit;

hydrocracking the portion of the first bottoms fraction under effective hydrocracking conditions in a hydrocracking stage having a continuous liquid environment; and

fractionating the hydrocracked first bottoms fraction in a second volume of the divided wall column fractionator to produce at least a second product fraction, a third product fraction, and a second common fraction that is passed to the upper undivided volume of the fractionator,

wherein the second product fraction has at least one improved property relative to the first product fraction and the third product fraction has at least one improved property relative to the bottoms fraction.

2. The method of claim 1, wherein the effective hydrotreating conditions include an LHSV from about 0.3 hr⁻

1 to about 5.0 hr<sup>−

1</sup>, a total pressure from about 500 psig (about 3.4 MPag) to about 3000 psig (about 20.7 MPag), and a temperature from about 650°

F. (about 343°

C.) to about 800°

F. (about 427°

C.).

3. The method of claim 2, wherein the effective hydrotreating conditions include a treat gas rate that provides an amount of hydrogen from about two times to about five times the hydrogen consumed during the hydrotreating.

4. The method of claim 1, further comprising hydrocracking the hydrotreated feed under effective hydrocracking conditions in a continuous gas phase environment prior to passing the hydrotreated feed to the first volume of the divided wall column, the effective hydrocracking conditions comprising a temperature from about 200°

C. to about 450°

C., a hydrogen partial pressure from about 5 barg (about 0.5 MPag) to about 300 barg (about 30 MPag), an LHSV from about 0.05 hr<sup>−

1</sup> to about 10 hr<sup>−

1</sup>, and a hydrogen treat gas rate from about two times to about fifteen times the hydrogen consumed during the hydrocracking.

5. The method of claim 1, wherein the effective conditions for hydrocracking in the continuous liquid phase environment include a temperature from about 200°

C. to about 450°

C., a hydrogen partial pressure from about 5 barg (about 0.5 MPag) to about 300 barg (about 30 MPag), and an LHSV from about 0.05 hr<sup>−

1</sup> to about 10 hr<sup>−

1</sup>.

6. The method of claim 5, wherein the portion of the first bottoms fraction is mixed with at least one of a diesel fraction from the first volume, a recycled diesel fraction from the second volume, and a recycled bottoms fraction from the second volume.

7. The method of claim 1, wherein the sulfur content of the second product fraction is lower than the sulfur content of the first product fraction, and wherein the sulfur content of the third product fraction is lower than the sulfur content of the first bottoms fraction.

8. The method of claim 1, wherein the height of the dividing wall is selected so that the second product fraction contains about 1 wt % or less of material corresponding to the first product fraction.

9. The method of claim 1, further comprising hydroprocessing the hydrocracked first bottoms fraction under effective hydroprocessing conditions in a continuous liquid phase environment, the hydroprocessing comprising hydrotreatment, catalytic dewaxing, ring-opening, and/or hydrofinishing.

10. A method for producing low sulfur distillate products, comprising:

hydrotreating a feedstock under effective hydrotreating conditions;

hydrocracking the hydrotreated feedstock in a first hydrocracking stage under first effective hydrocracking conditions;

fractionating the hydrocracked feedstock in a first volume of a divided wall column fractionator to produce at least a first diesel product fraction and a first bottoms fraction;

hydrocracking a portion of the first bottoms fraction in a second hydrocracking stage having a continuous liquid environment under second effective hydrocracking conditions;

dewaxing the hydrocracked portion of the bottoms fraction in a dewaxing stage having a continuous liquid environment under effective dewaxing conditions; and

fractionating the hydrocracked, dewaxed bottoms fraction in a second volume of the divided wall column fractionator to produce at least a second diesel product fraction and a second bottoms fraction,

wherein the second diesel fraction has at least one improved cold flow property relative to the first diesel fraction, and the second bottoms fraction has at least one improved cold flow property relative to the first bottoms fraction.

11. The method of claim 10, wherein the first effective hydrocracking conditions include a temperature from about 200°

C. to about 450°

C., a total pressure from about 5 barg (about 0.5 MPag) to about 300 barg (about 30 MPag), an LHSV from about 0.05 hr<sup>−

1</sup> to about 10 hr<sup>−

1</sup>, and a hydrogen treat gas rate from about two times to about fifteen times the hydrogen consumed during the hydrocracking, the first hydrocracking stage being in a continuous gas phase environment.

12. The method of claim 10, wherein the first effective hydrocracking conditions include a temperature from about 200°

C. to about 450°

C., a hydrogen partial pressure from about 5 barg (about 0.5 MPag) to about 300 barg (about 30 MPag), and an LHSV from about 0.05 hr<sup>−

1</sup> to about 10 hr<sup>−

1</sup>, the first hydrocracking stage being in a continuous liquid phase environment.

13. The method of claim 10, wherein the second effective hydrocracking conditions include a temperature from about 200°

C. to about 450°

C., a hydrogen partial pressure from about 5 barg (about 0.5 MPag) to about 300 barg (about 30 MPag), and an LHSV from about 0.05 hr<sup>−

1</sup> to about 10 hr<sup>−

1</sup>.

14. The method of claim 10, wherein the effective catalytic dewaxing conditions include a temperature from about 280°

C. to about 380°

C., a hydrogen partial pressure from about 300 psig (about 2.1 MPag) to about 3000 psig (about 20.7 MPag), and an LHSV from about 0.1 hr<sup>−

1</sup> to about 5.0 hr<sup>−

1</sup>.

15. The method of claim 10, wherein the cloud point of the second diesel fraction is at least about 10°

C. less than the cloud point of the first diesel fraction.

16. The method of claim 10, wherein the sulfur content of the first diesel fraction is about 15 wppm or less.

17. The method of claim 10, wherein the pour point of the second bottoms fraction is at least about 10°

C. less than the pour point of the first bottoms fraction.

18. The method of claim 10, wherein the effective hydrotreating conditions include an LHSV from about 0.3 hr⁻

1 to 5.0 hr<sup>−

1</sup>, a total pressure from about 500 psig (about 3.4 MPag) to about 3000 psig (about 20.7 MPag), a temperature from about 650°

F. (about 343°

C.) to about 800°

F. (about 427°

C.), and a hydrogen treat gas rate from about two times to about five times the hydrogen consumed during the hydrotreating.

19. The method of claim 10, wherein the second diesel fraction and the second bottoms fraction are not recycled to the dewaxing stage, and wherein said hydrocracking of the bottoms fraction further comprises hydrocracking of a portion of the first diesel fraction.