Pyrolysis tar pretreatment

Patent metadata

Field	Value
Publication number	US-11060039-B2
Application number	US-201716467776-A
Country	US
Kind code	B2
Filing date	Dec 1, 2017
Priority date	Dec 16, 2016
Publication date	Jul 13, 2021
Grant date	Jul 13, 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 I 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;
(d) during a time period of from t 1 to t 2 , hydroprocessing during a pretreatment mode at least a portion of the tar-fluid mixture in the presence of molecular hydrogen within a pretreatment reactor 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 pressure drop ΔP=ΔP 1 at t 1 , 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), and

(e) switching the pretreatment reactor from the pretreatment mode to a regeneration mode carried out after t 2 for a time period of from t 3 to t 4 , and during regeneration mode regenerating the pretreatment reactor under regeneration conditions which include a pressure drop ΔP 3 at t 3 , a temperature T Reg ≥T PT , a total pressure P Reg ≥3.5 MPa, and a molecular hydrogen GHSV Reg in the range of from 75 hr −1 to 750 hr −1 .

2. The process of claim 1 , wherein
(i) t 2 corresponds to the time at which the pretreatment reactor achieves a pressure drop ΔP 2 that is the lesser of (I) F *ΔP 1 , with F being in the range of from 1.5 to 20, or (II) a threshold ΔP≥2 psi; and
(ii) t 4 corresponds to the time at which the pretreatment reactor achieves a pressure drop ΔP 4 ≤0.5*ΔP 3 .

3. The process of claim 1 , wherein P Reg is ≤P PT and GHSV Reg is in the range of from 211 hr −1 to 600 hr −1 .

4. The process of claim 1 , wherein
(i) T Reg is in the range of from 325° C. to 425° C. during at least part of the regeneration, and
(ii) during the part of the regeneration where T Reg is in the range of from 325° C. to 425° C., ΔP exhibits a decrease of ≥0.5 psi, during which decrease ABS[d(ΔP)/dt] is ≥1 psi/hr.

5. 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 (ρ T ) ≥1.1 g/cm 3 .

6. 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. %.

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

8. 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.

9. 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.

10. The process of claim 1 , wherein T 1 ≥180° C., T 2 ≤300° C., t HS is in the range of from 5 minutes to 100 minutes, and R C is ≤R T 0.5 BN.

11. 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.

12. 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.

13. 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.

14. The process of claim 1 , further comprising:
(f) 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 1 ) ≥200° C., total pressure (P I ) ≥8 MPa, a space velocity (WHSV I ) ≥0.3 hr −1 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 .

15. The process of claim 14 , wherein (i) T I is 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) to 3200 SCF/B.

16. The process of claims 14 , wherein the hydroprocessing of step (f) 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.

17. The process of claim 14 , further comprising separating from the hydroprocessed 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 hydroproces sing 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).

18. The process of claim 17 , 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 hydroprocessing the second stream under Retreatment Hydroprocessing Conditions in the presence of molecular hydrogen to produce an upgraded tar comprising ≤0.5 wt. % sulfur, and the Retreatment Hydroprocessing Conditions include a temperature (T R ) in the range of from 370° C. to 415° C., a space velocity (WHSV R ) is in the range

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Heeter Glenn A
• Kandel Kapil
• Xu Teng

Classifications

• C10G2300/4006

  Temperature · CPC title

• C10G2300/201

  Impurities · CPC title

• C10G2300/207

  Acid gases, e.g. H2S, COS, SO2, HCN · CPC title

• C10G2300/4018

  Spatial velocity, e.g. LHSV, WHSV · CPC title

• C10G31/10

  with the aid of centrifugal force · CPC title