Method of removing solids by modifying a liquid level in a distillation tower

Patent metadata

Field	Value
Publication number	US-9562719-B2
Application number	US-201414516717-A
Country	US
Kind code	B2
Filing date	Oct 17, 2014
Priority date	Dec 6, 2013
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

The present disclosure provides a method of separating a feed stream in a distillation tower. The method includes maintaining a controlled freeze zone section in a distillation tower; maintaining a melt tray assembly within the controlled freeze zone section that operates at a temperature and pressure at which solid melts; forming solids in a controlled freeze zone section; raising a liquid level of a liquid in the melt tray assembly when the solids accumulate on a mechanical component in the controlled freeze zone section; raising a liquid temperature of the liquid while raising the liquid level; and lowering the liquid level after at least one of (a) a predetermined time period has passed and (b) an alternative temperature of the mechanical component is within an expected temperature range of a baseline temperature of the mechanical component.

First claim

What is claimed is:

1. A method of separating a feed stream in a distillation tower comprising:
maintaining a controlled freeze zone section in the distillation tower that operates at a temperature and pressure at which a solid forms;
maintaining a melt tray assembly within the controlled freeze zone section that operates at a temperature and pressure at which the solid melts;
forming solids in the controlled freeze zone section;
raising a liquid level of a liquid in the melt tray assembly when the solids accumulate on a mechanical component in the controlled freeze zone section;
raising a liquid temperature of the liquid while raising the liquid level; and
lowering the liquid level after at least one of (a) a predetermined time period has passed and (b) an alternative temperature of the mechanical component is within an expected temperature range of a baseline temperature of the mechanical component.

2. The method of claim 1 , wherein raising the liquid level comprises determining whether the solids have accumulated on the mechanical component.

3. The method of claim 1 , wherein the mechanical component comprises a controlled freeze zone wall.

4. The method of claim 1 , wherein the predetermined time period is about 5 to 30 minutes.

5. The method of claim 1 , wherein increasing the liquid temperature comprises applying heat to the liquid with at least one of (i) a heat mechanism included in the melt tray assembly and (ii) an external heating mechanism that is external to the melt tray assembly.

6. The method of claim 5 , wherein the heat mechanism comprises a melt coil.

7. The method of claim 5 , wherein the external heating mechanism comprises at least one of a first reboiler, a second reboiler and a vapor stream.

8. The method of claim 1 , further comprising detecting the baseline temperature before forming the solids in the controlled freeze zone section; and detecting the alternative temperature after forming the solids.

9. The method of claim 8 , further comprising repeatedly detecting the alternative temperature and repeatedly determining whether the alternative temperature is within the expected temperature range.

10. A method of producing a hydrocarbon from a feed stream in a distillation tower comprising:
maintaining a controlled freeze zone section in the distillation tower that operates at a temperature and pressure at which a feed stream forms a solid;
maintaining a melt tray assembly within the controlled freeze zone section that operates at a temperature and pressure at which the solid melts;
forming solids in the controlled freeze zone section;
raising a liquid level of a liquid in the melt tray assembly when the solids accumulate on a mechanical component in the controlled freeze zone section;
raising a liquid temperature of the liquid while raising the liquid level;
lowering the liquid level after at least one of (a) a predetermined time period passed and (b) a detected temperature of the mechanical component is within an expected temperature range of a baseline temperature of the mechanical component; and
producing hydrocarbons from the feed stream.

11. The method of claim 10 , wherein raising the liquid level comprises determining whether the solids have accumulated on the mechanical component.

12. The method of claim 10 , wherein the mechanical component comprises a controlled freeze zone wall.

13. The method of claim 10 , wherein the predetermined time period is about 5 to 30 minutes.

14. The method of claim 10 , wherein increasing the liquid temperature comprises applying heat to the liquid with at least one of (i) a heat mechanism included in the melt tray assembly and (ii) an external heating mechanism that is external to the melt tray assembly.

15. The method of claim 14 , wherein the heat mechanism comprises a melt coil.

16. The method of claim 14 , wherein the external heating mechanism comprises at least one of a first reboiler, a second reboiler,a vapor stream, and a heat tracing.

17. The method of claim 10 , further comprising detecting the baseline temperature before forming the solid in the controlled freeze zone section; and detecting the alternative temperature after forming the solids.

18. The method of claim 17 , further comprising repeatedly detecting the alternative temperature and repeatedly determining whether the alternative temperature is within the expected temperature range.

Assignees

• Valencia Jaime A
• Northrop Paul Scott
• Exxonmobil Upstream Res Co

Inventors

• Valencia Jaime A
• Northrop Paul Scott

Classifications

• F25J2200/02

  in a single pressure main column system · CPC title

• C10L3/104

  Carbon dioxide · CPC title

• F25J2280/20

  Control for stopping, deriming or defrosting after an emergency shut-down of the installation or for back up system · CPC title

• C07C7/05

  with the aid of auxiliary compounds · CPC title

• F25J3/061

  Natural gas or substitute natural gas · CPC title