Method and apparatus for managing hydrate formation in the processing of a hydrocarbon stream

Patent metadata

Field	Value
Publication number	US-9522860-B2
Application number	US-201214036722-A
Country	US
Kind code	B2
Filing date	Mar 6, 2012
Priority date	Mar 7, 2011
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

A method and system are disclosed for managing hydrate formation in a process that converts a hydrocarbon stream into C 2 unsaturates, such as ethylene and/or acetylenes. The method includes adding a hydrate inhibitor to a hydrocarbon stream to lower the hydrate formation point of the mixture stream from an initial hydrate formation point (H I ) of the hydrocarbon stream to a depressed hydrate formation point (H D ) of the mixture stream. Then, the mixture stream is depressurized to adiabatically cool the stream to a temperature (T), wherein the H D <T<H I . Then, at least a portion of the mixture stream is vaporized and the vaporized portion of the mixture stream is separated from the unvaporized portion of the mixture stream. Once separated, at least a portion of the vaporized portion is converted into product, such as ethylene and/or acetylene.

First claim

What is claimed is:

1. A method of processing a hydrocarbon stream comprising:
providing a hydrocarbon stream having an initial hydrate formation point (H I );
adding a hydrate inhibitor to the hydrocarbon stream to form a mixture stream and lower the hydrate formation point from the initial hydrate formation point (H I ) of the hydrocarbon stream to a depressed hydrate formation point (H D ) of the mixture stream;
cooling the mixture stream by passing the mixture stream through a first side of a heat exchanger;
depressurizing the mixture stream to adiabatically cool the mixture stream to a temperature (T), wherein the H D <T<H I ;
vaporizing at least a portion of the mixture stream;
separating a first product that includes at least a portion of the vaporized portion of the mixture stream from a second product that includes at least a portion of the unvaporized portion of the mixture stream;
heating at least a portion of the first product by passing the portion of the first product through a second side of the heat exchanger; and
processing at least a portion of the first product in a pyrolysis reactor to produce C2 unsaturates.

2. The method of claim 1 , comprising passing the mixture stream through a static mixer to intermingle the compounds in the mixture stream upstream of the depressurizing.

3. The method of claim 1 , wherein the vaporizing comprises heating the mixture stream to a temperature sufficient to vaporize at least a portion of the mixture stream.

4. The method of claim 1 , wherein the processing involves heating the at least a portion of the first product to temperatures in the range of 500° C. to 880° C. to produce the C 2 unsaturates.

5. The method of claim 4 , wherein the processing involves heating the at least a portion of the first product to temperatures in the range of 1200° C. to 2000° C. to produce the C 2 unsaturates.

6. The method of claim 1 , wherein the hydrocarbon stream is at a pressure in the range of 700 psia to 1100 psia (4826 kPaa to 7584 kPaa).

7. The method of claim 1 , wherein the depressurizing comprises reducing the pressure of the mixture stream to pressure in the range of 50 psia to 400 psia (345 kPaa to 2758 kPaa).

8. The method of claim 1 , wherein depressurizing comprises reducing the temperature of the mixture stream to a temperature in the range of 20° F. to −20° F. (−6.7° C. to −28.9° C.).

9. The method of claim 1 , wherein hydrocarbon stream comprises≧90 wt % ethane.

10. The method of claim 9 , wherein the vaporizing comprises heating the mixture stream to vaporize≧90 wt % of the ethane in the mixture stream.

11. The method of claim 1 , wherein hydrocarbon stream comprises≧90 wt % methane.

12. The method of claim 1 , wherein the hydrate inhibitor has a concentration of thermodynamic inhibitor that is in the range of 60 wt % to 100 wt % of the hydrate inhibitor.

13. The method of claim 1 , wherein the hydrate inhibitor comprises one or more of mono-ethylene glycol (MEG) and tri-ethylene glycol (TEG).

Assignees

• White William R
• Kendall James L
• Bancroft Jennifer L
• Sellen Russell Dean
• Exxonmobil Chemical Patents Inc

Inventors

• White William R
• Kendall James L
• Bancroft Jennifer L
• Sellen Russell Dean

Classifications

• C10G29/22

  containing oxygen as the only hetero atom · CPC title

• C10G55/04

  including at least one thermal cracking step · CPC title

• C07C5/327

  Formation of non-aromatic carbon-to-carbon double bonds only · CPC title

• G06F8/61

  Installation · CPC title

• C10G53/02

  plural serial stages only · CPC title