Process for vacuum distillation of a crude hydrocarbon stream

Patent metadata

Field	Value
Publication number	US-9783741-B2
Application number	US-201314372335-A
Country	US
Kind code	B2
Filing date	Jan 15, 2013
Priority date	Jan 17, 2012
Publication date	Oct 10, 2017
Grant date	Oct 10, 2017

Abstract

Disclosed is a process for vacuum distillation of a hydrocarbon stream comprising i) passing a hydrocarbon stream into a preflash vessel maintained under conditions to separate the hydrocarbon stream into a preflash liquid and a preflash vapor, ii) passing the preflash liquid into a vacuum furnace maintained under conditions to heat and partly vaporize the preflash liquid, iii) passing the heated furnace effluent into a zone located in the lower part of a vacuum distillation column maintained under fractionating conditions, and iv) passing the preflash vapor into the vacuum distillation column into a further zone located in the lower part of the vacuum distillation column.

First claim

That which is claimed is:

1. A process for the vacuum distillation of a long residue hydrocarbon stream yielded as a bottoms product from a crude oil atmospheric column and having an initial boiling point of at least 230° C. wherein the process comprises:
i) passing the long residue hydrocarbon stream into a preflash vessel maintained under mild vacuum conditions and providing for separating the long residue hydrocarbon stream into a preflash liquid and a preflash vapor;
ii) passing the preflash liquid into a vacuum furnace maintained under conditions providing for heating and partly vaporizing the preflash liquid thereby yielding a heated furnace effluent;
iii) passing the heated furnace effluent to a vacuum distillation column having a length and defining a lower part and a middle part, wherein the lower part is positioned between a bottom to the vacuum distillation column and up to 40% of the length of the vacuum distillation column and wherein the lower part includes a first zone located above a second zone providing for receiving the preflash liquid, and introducing the heated furnace effluent into the first zone that is maintained under fractionating conditions;
iv) yielding from the vacuum distillation column a short residue stream, whish is passed to a stripping vessel, and passing the preflash vapor to the stripping vessel, wherein the stripping vessel provides for stripping of the short residue stream to yield a vapor stream; and
v) passing the vapor stream into the second zone.

2. The process according to claim 1 , wherein the preflash vapor is heated in the furnace convection bank prior to passing it into the stripping vessel.

3. The process according to claim 1 , wherein the preflash vapor is heated by high pressure steam or hot oil prior to passing it into the stripping vessel.

4. The process according to claim 1 , wherein the vacuum distillation column is operated at a pressure of less than 1 atmosphere absolute.

5. The process according to claim 4 , wherein the initial boiling point of the long residue hydrocarbon stream is at least 250° C.

6. The process according to claim 5 , wherein the heated furnace effluent is heated to a temperature in the range of from 380° C. to 430° C.

7. A high vacuum unit (HVU) for vacuum distillation of a long residue hydrocarbon stream, the unit comprising:
a preflash vessel, providing for separating the long residue hydrocarbon stream into a preflash liquid and a preflash vapor;
a vacuum furnace operatively connected to the preflash vessel and providing for heating and partly vaporizing the preflash liquid to yield a heated furnace effluent;
a vacuum distillation column operatively connected to the vacuum furnace and having a length and defining a lower part and a middle part, wherein the lower part is positioned between a bottom to the vacuum distillation column and up to 40% of the length of the vacuum distillation column, wherein the lower part includes a first zone located above a second zone providing for receiving the heated furnace effluent;
a stripping vessel operatively connected to the vacuum distillation column providing for receiving a short residue stream from the vacuum distillation column, and operatively connected to the preflash vessel for receiving the preflash vapor, and operatively connected to the vacuum distillation column providing for passing a vapor system stream yielded from the stripping vessel.

Assignees

• Shell Oil Co

Inventors

• Amale Amit Sureshrao
• Van Doesburg Edmundo Steven
• Wilkinson Peter Mervyn

Classifications

• C10G2300/107

  Atmospheric residues having a boiling point of at least about 538 °C · CPC title

• C10G7/06 Primary

  Vacuum distillation · CPC title

• C10G2300/4037

  In-situ processes · CPC title

• C10G2300/1044

  Heavy gasoline or naphtha having a boiling range of about 100 - 180 °C · CPC title

• B01D3/10

  Vacuum distillation (B01D3/12 takes precedence) · CPC title