Pyrolysis tar pretreatment

Patent metadata

Field	Value
Publication number	US-10988698-B2
Application number	US-201716467781-A
Country	US
Kind code	B2
Filing date	Dec 1, 2017
Priority date	Dec 16, 2016
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

This invention relates to thermally-treating and hydroprocessing pyrolysis tar to produce a hydroprocessed pyrolysis tar, but without excessive foulant accumulation during the hydroprocessing. The invention also relates to upgrading the hydroprocessed tar by additional hydroprocessing; to products of such processing; to blends comprising one or more of such products; and to the use of such products and blends, e.g., as lubricants, fuels, and/or constituents thereof.

First claim

The invention claimed is:

1. A pyrolysis tar pretreatment process, comprising:
(a) providing a pyrolysis tar having a reactivity (R T ) >28 BN, wherein, at least 70 wt. % of the pyrolysis tar's components have a normal boiling point of at least 290° C., based on the total weight of the pyrolysis tar;
(b) maintaining the pyrolysis tar within a temperature range of from T 1 to T 2 for a time (t HS ) sufficient to produce a pyrolysis tar composition having a reactivity R C <R T and an insolubles content IC C < 6 wt. %, wherein, T 1 is ≥150° C., T 2 is ≤320° C., and t HS is ≥1 minute;
(c) combining the pyrolysis tar composition with a utility fluid comprising hydrocarbon to produce a tar-fluid mixture having a reactivity R M ≤18 BN; and
(d) hydroprocessing at least a portion of the tar-fluid mixture in the presence of molecular hydrogen to produce a pretreater effluent comprising a vapor portion and a liquid portion, wherein:
(i) the liquid portion comprises a pretreated tar-fluid mixture which includes a pretreated pyrolysis tar,
(ii) the pretreated tar-fluid mixture has a reactivity (R F )<12 BN, and
(iii) the hydroprocessing is carried out under Pretreatment Hydroprocessing Conditions which include a temperature T PT ≤400° C., a space velocity (WHSV PT ) ≥0.3 hr −1 based on the weight of the hydroprocessed portion of the tar-fluid mixture, a total pressure (P PT ) ≥8 MPa, and supplying the molecular hydrogen at a rate <3000 standard cubic feet per barrel of the hydroprocessed portion of the tar-fluid mixture (SCF/B).

2. The process of claim 1 , wherein R T is in the range of from 29 BN to 45 BN, ≥90 wt. % of the pyrolysis tar has a normal boiling point ≥290° C., and wherein the pyrolysis tar has an Insolubles Content (IC T )≤6 wt. %, an I N ≥ 80, a 15° C. kinematic viscosity ≥600 cSt, and a 15° C. density (ρT) ≥1.1 g/cm 3 .

3. The process of claim 1 , wherein IC C is ≤5 wt. %.

4. The process of claim 1 , wherein the pyrolysis tar is a steam cracker tar having one or more of (i) a TH content in the range of from 5.0 wt. % to 40.0 wt. %; (ii) an API gravity (measured at a temperature of 15.8° C.) of ≤8.5° API; (iii) a 50° C. viscosity in the range of 1×10 3 cSt to 1.0×10 7 cSt; and (iv) a sulfur content that is >0.5 wt. %.

5. The process of claim 1 , wherein t HS is in the range of from 10 minutes to 400 minutes, R C ≤28 BN, and R C is ≤R T −4 BN.

6. The process of claim 1 , wherein the tar-fluid mixture has 50° C. kinematic viscosity that is ≤500 cSt, and 12 BN<R M ≤18 BN.

7. The process of claim 1 , wherein t HS is in the range of from 30 minutes to 400 minutes, R C is ≤R T − 8 BN, and R F ≤11 BN.

8. The process of claim 1 , wherein T 1 ≥180 ° C., T 1 ≤ 300° C., t HS is in the range of from 5 minutes to 100 minutes, and R C is ≤R T − 0.5 BN.

9. The process of claim 1 , wherein the utility fluid comprises aromatic hydrocarbon and has a 10% distillation point ≥60° C. and a 90% distillation point ≤425° C.

10. The process of claim 1 , wherein the tar-fluid mixture comprises 50 wt. % to 70 wt. % of pyrolysis tar, with ≥90 wt. % of the balance of the tar-fluid mixture comprising the utility fluid.

11. The process of claim 1 , wherein (i) T PT is in the range of from 220° C. to 300° C., WHSV PT is in the range of from 1.5 hr −1 to 3.5 hr −1 , and the molecular hydrogen supply rate is in a range of about 300 (SCF/B) to 1000 SCF/B, and P PT is in the range of from 6 MPa to 13.1 MPa; and (ii) the Pretreatment Hydroprocessing Conditions further include a molecular hydrogen consumption rate in the range of from 100 standard cubic feet per barrel of the pyrolysis tar composition in the tar-fluid mixture (SCF/B) to 600 SCF/B.

12. The process of claim 1 , wherein the hydroprocessing of step (d) is carried out in a first reactor, and the first reactor has a pressure drop of ≤15 psi during substantially continuous operation for at least fifteen days.

13. The process of claim 1 , further comprising
(e) hydroprocessing in the presence of molecular hydrogen at least a portion of the pretreater effluent under Intermediate Hydroprocessing Conditions to produce a hydroprocessor effluent comprising hydroprocessed pyrolysis tar, wherein:
(i) the Intermediate Hydroprocessing Conditions include a temperature (T 1 ) ≥200° C., total pressure (“P I ”) ≥8 MPa, a space velocity (WHSV I ) ≥0.3 hr −l based on the weight of the liquid portion of the pretreater effluent hydroprocessed in (e), and a molecular hydrogen supply rate ≥3000 standard cubic feet of the pretreated tar hydroprocessed in (e) (SCF/B), and
(ii) WHSV I <WHSV PT .

14. The process of claim 13 , wherein (i) T I in the range of from 360° C. to 410° C., T I >T PT , WHSV I is in the range of from 0.5 hr −1 to 1.2 hr −1 , the molecular hydrogen supply rate is in the range of from 3000 SCF/B to 5000 SCF/B, and P I is in the range of from 6 MPa to 13.1 MPa; and (ii) the Intermediate Hydroprocessing Conditions further include a molecular hydrogen consumption rate in the range of from 1600 standard cubic feet per barrel of tar in the pretreater effluent (SCF/B) 3200 SCF/B.

15. The process of claim 13 , wherein the hydroproces sing of step (e) is carried out in a second reactor, and the second reactor exhibits a 566° C.+ conversion of at least 20 wt. % substantially continuously for at least thirty days.

16. The process of claim 13 , further comprising: separating from the hydroprocessor effluent (i) a primarily vapor-phase first stream comprising at least a portion of any unreacted molecular hydrogen; (ii) a primarily liquid-phase second stream comprising at least a portion of the hydroprocessed pyrolysis tar, and (iii) a primarily liquid-phase third stream comprising at least a portion of any unreacted utility fluid; recycling to the hydroprocessing of steps (d) and/or (e) at least a portion of the first stream, and recycling at least a portion of the third stream to step (c).

17. The process of claim 2 , further comprising
(e) hydroproces sing in the presence of molecular hydrogen at least a portion of the pretreater effluent under Intermediate Hydroproces sing Conditions to produce a hydroprocessor effluent comprising hydroprocessed pyrolysis tar, wherein:
(i) the Intermediate Hydroprocessing Conditions include a temperature (T I ) ≥200° C., total pressure (“P I ”) ≥8 MPa, a space velocity (WHSV I ) ≥0.3 hr −l based on the weight of the liquid portion of the pretreater effluent hydroprocessed in (e), and a molecular hydrogen supply rate ≥3000 standard cubic feet of the pretreated tar hydroprocessed in (e) (SCF/B), and
(ii) WHSV I ≤WHSV PT ;

(f) separating from the hydroprocessor effluent (i) a primarily vapor-phase first stream comprising at least a portion of any unreacted molecular hydrogen; (ii) a primarily liquid-phase second stream comprising at least a portion of the hydroprocessed pyrolysis tar, and (iii) a primarily liquid-phase third stream comprising at least a portion of any unreacted utility fluid;
(g) recycling to the hydroprocessing of steps (d) and/or (e) at least a portion of the first stream, and
(h) recycling at least a portion of the third stream to step (c), wherein the second stream has a 15° C. density (ρ2)≤ρT−0.12 g/cm 3 .

18. The process of claim 16 , wherein the second stream comprises ≥1 wt. % of sulfur and <10 wt. % of hydrocarbon having a 10% distillation point ≥60° C. and a 90% distillation point ≤425° C., and wherein the process further comprises hydroproces sing the second stream under Retreatment Hydroproces sing Conditions in the presence of molecular hydrogen to

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Kandel Kapil
• Emanuele Krystle J
• Heeter Glenn A
• Agrawal Gaurav
• Yeh Jeffrey C
• Xu Teng

Classifications

• C10G69/06 Primary

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

• C10G45/00 Primary

  Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds · CPC title

• C10G2300/304

  Pour point, cloud point, cold flow properties · CPC title

• C10G2300/301

  Boiling range · CPC title

• C10G2300/308

  Gravity, density, e.g. API · CPC title