Process for recovering heat from a hydrocarbon separation

• US 10,315,971 B2
• Filed: 11/15/2017
• Issued: 06/11/2019
• Est. Priority Date: 12/29/2016
• Status: Active Grant

• Current Assignee: UOP Llc (Honeywell International Inc.)
• Original Assignee: UOP Llc (Honeywell International Inc.)
• Inventors: King, Stephen T., Van de Cotte, Michael R., Kanyuh, Adam J., Kozup, Steven C.
• Primary Examiner(s): Robinson, Renee
• Application Number:
  US15/814,288
• Publication Number:
  US 20180185766A1
• Time in Patent Office: 573 Days
• CPC Class Codes: B01D 1/2809 At least two streams are compressed
• CPC Class Codes: B01D 1/2812 The vapour is coming from different sources
• CPC Class Codes: B01D 1/2843 The compressed vapour is divided in at least two streams
• CPC Class Codes: B01D 1/2846 The compressed vapour is not directed to the same apparatus from which the vapour was taken off
• CPC Class Codes: B01D 1/2856 The compressed vapour is used for heating a reboiler or a heat exchanger outside an evaporator
• CPC Class Codes: B01D 1/2881 Compression specifications (e.g. pressure, temperature, processes)
• CPC Class Codes: B01D 1/2884 Multiple effect compression B01D1/2815 takes precedence
• 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: B01D 3/4227 Head- and bottom stream
• CPC Class Codes: C07C 11/06 Propene
• CPC Class Codes: C07C 7/005 Processes comprising at least two steps in series
• CPC Class Codes: C07C 7/04 by distillation
• CPC Class Codes: C07C 7/09 by fractional condensation
• CPC Class Codes: Y02P 20/10 Process efficiency
• CPC Class Codes: Y02P 20/50 Improvements relating to the production of bulk chemicals
• CPC Class Codes: Y02P 70/10 Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Abstract

Systems and processes for heat recovery associated with the separation of hydrocarbon components. Two compressors are used to compress a portion of an overhead vapor stream from a fractionation column. A pressure of the liquid portion of the compressed overhead is reduced and used to recover heat from an overhead of another separation zone having a fractionation column. Once the heat has been recovered the stream is recompressed. The recovered heat may be removed from the recompressed stream in a reboiler of another fractionation column. The fractionation columns may comprise a deethanizer stripper, propane-propylene splitter, and a depropanizer column.

Claims

1. A process for separating hydrocarbons and recovering heat comprising:

separating a stream comprising C4−

hydrocarbons in a first separation zone into an overhead stream and a C3+ bottoms stream;

separating the C3+ bottoms stream in a second separation zone into a propylene overhead stream and a bottoms stream comprising propane;

compressing the propylene overhead stream in a first compression zone configured to provide a compressed propylene overhead stream;

recovering heat from a first portion of the compressed propylene overhead stream in a heat exchange zone associated with the second separation zone;

condensing a second portion of the compressed propylene overhead stream in a separation vessel, the separation vessel providing a propylene vapor stream and a propylene liquid stream;

reducing a pressure of at least a portion of the propylene liquid stream to provide a reduced pressure stream;

recovering heat from the reduced pressure stream in a second heat exchange zone, the second heat exchange zone associated with the first separation zone and being configured to condense a portion of the overhead stream and provide a vaporized propylene stream;

compressing the vaporized propylene stream in a second compression zone configured to provide a re-compressed propylene stream; and

,

mixing the re-compressed propylene stream with the second portion of the compressed propylene overhead stream in the separation vessel.

2. The process of claim 1 further comprising:

compressing the propylene vapor stream from the separation vessel in the second compression zone.

3. The process of claim 2 further comprising:

removing heat from the re-compressed propylene stream before the re-compressed propylene stream is mixed with the second portion of the compressed propylene overhead stream in the separation vessel.

4. The process of claim 3 wherein the heat is removed from the re-compressed propylene stream in a third heat exchange zone associated with a third separation zone configured to receive the bottoms stream from the second separation zone.

5. The process of claim 1 further comprising:

separating the first portion of the compressed propylene overhead stream in a fractionation column in the second separation zone.

6. The process of claim 1 further comprising:

recovering a second portion of the propylene liquid stream as a propylene product stream.

7. The process of claim 1 further comprising:

refluxing a third portion of the propylene liquid stream from the separation vessel to a fractionation column in the second separation zone.

8. The process of claim 1 wherein the first separation zone comprises two fractionation columns, and wherein the second separation zone comprises a fractionation column.

9. The process of claim 1 further comprising:

transferring heat from the re-compressed propylene stream to a third separation zone configured to receive the bottoms stream from the second separation zone.

10. A process for separating hydrocarbons and recovering heat comprising:

separating a stream comprising C4−

hydrocarbons in a first separation zone configured to separate the stream into an overhead stream and a C3+ bottoms stream;

passing the C3+ bottoms stream to a second separation zone configured to separate the C3+ bottoms stream and provide a propylene overhead stream and a bottoms stream, the bottom stream including propane;

passing the bottoms stream of the second separation zone to a third separation zone;

passing the propylene overhead stream to a first compression zone configured to compress the propylene overhead stream and provide a compressed propylene overhead stream;

passing a first portion of the compressed propylene overhead stream to a heat exchange zone associated with the second separation zone configured to remove heat from the first portion of the compressed propylene overhead stream;

passing a second portion of the compressed propylene overhead stream to a separation vessel configured to allow the second portion of the compressed propylene overhead stream to be cooled and separate into a vapor propylene stream and a liquid propylene stream;

reducing a pressure of at least a portion of the liquid propylene stream to provide a reduced pressure stream, the reduced pressure stream comprising a mixture of liquid and vapor;

passing the reduced pressure stream to a second heat exchange zone associated with the first separation zone and configured to vaporize liquid in the reduced pressure stream and provide a vaporized propylene stream, wherein the second heat exchange zone also receives a portion of the overhead stream from the first separation zone;

passing the vaporized propylene stream to a second compression zone configured to compress the vaporized propylene stream and provide a re-compressed propylene stream; and

,

passing the re-compressed propylene stream to the separation vessel.

11. The process of claim 10 further comprising:

passing the vapor propylene stream from the separation vessel to the second compression zone.

12. The process of claim 11 further comprising:

removing heat from the re-compressed propylene stream before the propylene is passed to the separation vessel.

13. The process of claim 12 further comprising:

passing the re-compressed propylene stream to a third heat exchange zone associated with the third separation zone; and

,

then passing the re-compressed propylene stream from the third heat exchange zone to the separation vessel.

14. The process of claim 10 further comprising:

passing the first portion of the compressed propylene overhead stream from the first heat exchange zone to a fractionation column in the second separation zone.

15. The process of claim 10 further comprising:

recovering a second portion of the liquid propylene stream as a propylene product stream.

16. The process of claim 10 further comprising:

passing a third portion of the liquid propylene stream to a fractionation column in the second separation zone.

17. The process of claim 10 wherein the first separation zone comprises a fractionation column, and wherein the second separation zone comprises a fractionation column.

18. The process of claim 10 further comprising:

removing heat from the re-compressed propylene stream before the propylene is passed to the separation vessel.