Method for cracking a hydrocarbon feedstock in a steam cracker unit

Patent metadata

Field	Value
Publication number	US-2016137933-A1
Application number	US-201414902153-A
Country	US
Kind code	A1
Filing date	Jun 30, 2014
Priority date	Jul 2, 2013
Publication date	May 19, 2016
Grant date	—

Abstract

The present invention relates to process for cracking a hydrocarbon feedstock in a steam cracker unit, comprising the following steps of: feeding a hydrocarbon feedstock to a first hydrocracking unit, feeding the hydrocarbon feedstock thus cracked to a separation unit for obtaining a stream high in paraffins and naphtenes, a stream high in heavy aromatics and a stream high in mono-aromatics feeding the stream high in paraffins and naphtenes to a second hydrocracking unit, wherein the process conditions in the first hydrocracking unit differ from the process conditions in the second hydrocracking unit, separating the stream thus hydrocracked in the second hydrocracking unit in a high content aromatics stream and gaseous stream comprising C2-C4 paraffins, hydrogen and methane, feeding the gaseous stream to a steam cracker unit.

First claim

1 . A process for cracking a hydrocarbon feedstock in a steam cracker unit, comprising:
feeding a hydrocarbon feedstock to a first hydrocracking unit, feeding the hydrocarbon feedstock thus cracked to a separation unit for obtaining a stream high in paraffins and naphtenes, a stream high in heavy aromatics and a stream high in mono-aromatics feeding the stream high in paraffins and naphtenes to a second hydrocracking unit, wherein the process conditions in the first hydrocracking unit differ from the process conditions in the second hydrocracking unit, separating the stream thus hydrocracked in the second hydrocracking unit into a high content aromatics stream and gaseous stream comprising C2-C4 paraffins, hydrogen and methane, feeding the gaseous stream to a steam cracker unit.

2 . The process according to claim 1 , further comprising returning said stream high in heavy aromatics to the first hydrocracking unit.

3 . The process according to claim 1 , further comprising
separating C2-C4 paraffins from said gaseous stream, and feeding said C2-C4 paraffins thus separated to the furnace section of a steam cracker unit.

4 . The process according to claim 1 , further comprising separating C3-C4 paraffins from said C2-C4 paraffins and feeding said C3-C4 paraffins to a dehydrogenation unit for obtaining hydrogen, C3-olefins and C4-olefins.

5 . The process according to claim 1 , wherein separating said C2-C4 paraffins from said gaseous stream is carried out by cryogenic distillation or solvent extraction.

6 . The process according to claim 1 , further comprising separating C2-C4 paraffins in individual streams, each stream predominantly comprising C2 paraffins, C3 paraffins and C4 paraffins, respectively, and feeding each individual stream to a specific furnace section of said steam cracker unit and/or to a dehydrogenation unit.

7 . The process according to claim 1 , further comprising recovering from said gaseous stream a stream predominantly comprising hydrogen and methane and recycling said stream to the first and/or second hydrocracking unit.

8 . The process according to claim 1 further comprising recovering mono-aromatics from said stream high in heavy aromatics before returning said stream high in heavy aromatics to the first hydrocracking unit.

9 . The process according to claim 1 , wherein the separation unit comprises a distillation unit and an extraction unit, wherein the top stream from the distillation unit is sent to the inlet of said extraction unit.

10 . The process according to claim 1 , further comprising returning said high content aromatics stream to said separation unit, preferably to the inlet of said extraction unit.

11 . The process according to claim 1 , wherein the temperature in the first hydrocracking unit is lower than the temperature in the second hydrocracking unit.

12 . The process according to claim 1 , wherein the hydrogen partial pressure in the first hydrocracking unit is higher than the hydrogen partial pressure in the second hydrocracking unit.

13 . The process according to claim 1 , wherein the reactor type design of the first and second hydrocracking unit is chosen from the group of the fixed bed type, ebulating bed reactor type and the slurry type, especially the reactor type design of both the first and second hydrocracking unit is of the fixed bed type.

14 . The process according to claim 1 , wherein the hydrocarbon feedstock to said first hydrocracking unit is of the type naphtha, kerosene, diesel, atmospheric gas oil (AGO), waxes, vacuum gas oil (VGO), atmospheric residue, vacuum residue and gas condensates, or combinations thereof, especially naphtha and diesel.

15 . The process according to claim 1 , wherein said first hydrocracking unit is operated at a temperature of 200-600° C. and a pressure of 3-35 MPa.

16 . The process according to claim 1 , wherein said second hydrocracking unit is operated at a temperature of 300-550° C., a pressure of 300-5000 kPa gauge and a Weight Hourly Space Velocity of 0.1-10 h −1 .

17 . (canceled)

18 . The process according to claim 16 , wherein the temperature is 300-450° C., the pressure is 300-5000 kPa gauge, and the Weight Hourly Space Velocity is 0.1-10 −1 .

19 . The process according to claim 16 , wherein the temperature is 300-400° C., the pressure is 600-3000 kPa gauge, and the Weight Hourly Space Velocity is 0.2-2 −1 .

Assignees

• Saudi Basic Ind Corp
• Sabic Global Technologies Bv

Inventors

• Ward Andrew Mark
• Oprins Arno Johannes Maria
• Housmans Thomas Hubertus Maria
• Narayanaswamy Ravichander
• Rajagopalan Vijayanand

Classifications

• C10G69/06 Primary

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

• C10G2400/20

  C2-C4 olefins · CPC title

• C10G2400/30

  Aromatics · CPC title

• C10G9/36

  with heated gases or vapours · CPC title

• Y02P30/40

  Ethylene production · CPC title