Refrigerant composition control

Patent metadata

Field	Value
Publication number	US-10132561-B2
Application number	US-54090309-A
Country	US
Kind code	B2
Filing date	Aug 13, 2009
Priority date	Aug 13, 2009
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A system and method for removal of a contaminant comprising removing a liquefied portion of a refrigerant stream comprising nitrogen from a reverse Brayton cycle refrigerant system, introducing the liquefied refrigerant stream into a contaminant removal column as a reflux stream removing a contaminant stream from the bottom of the contaminant removal column, removing a vapor stream enriched in nitrogen from the top of the contaminant removal column, and introducing the vapor stream enriched in nitrogen back into the reverse Brayton cycle refrigerant system.

First claim

The invention claimed is:

1. A method for removal of a hydrocarbon contaminant from a refrigerant stream predominantly comprising nitrogen, comprising:
removing a liquefied portion of the refrigerant stream comprising nitrogen from a reverse Brayton cycle refrigerant system;
introducing at least a portion of said liquefied portion of the refrigerant stream predominantly comprising nitrogen into the top of a contaminant removal column as a reflux stream;
removing a hydrocarbon contaminant stream from the bottom of the contaminant removal column, wherein the hydrocarbon contaminant stream is a hydrocarbon rich stream;
combining the hydrocarbon rich stream with a liquefied subcooled natural gas stream to be used as a liquid natural gas product, wherein the liquefied subcooled natural gas stream is formed by indirect heat exchange of a natural gas feed stream against the refrigerant stream in a liquefier heat exchanger;
removing a vapor stream enriched in nitrogen from the top of the contaminant removal column; and
introducing the vapor stream enriched in nitrogen back into the reverse Brayton cycle refrigerant system, wherein the vapor stream enriched in nitrogen is purified in the contaminant removal column for further use as a refrigerant.

2. The method of claim 1 , wherein prior to removing said liquefied portion of the refrigerant stream comprising nitrogen from the reverse Brayton cycle refrigerant system, said liquefied portion of the refrigerant stream is cooled and liquefied by indirect heat exchange.

3. The method of claim 1 , wherein the method is performed on a Floating Production Storage and Offloading vessel.

4. A method for removal of a hydrocarbon contaminant from a refrigerant stream predominantly comprising nitrogen, comprising:
removing a portion of a gaseous refrigerant stream predominantly comprising nitrogen from a reverse Brayton cycle refrigerant system;
liquefying the removed portion of the gaseous refrigerant stream;
introducing the liquefied refrigerant stream into the top of a contaminant removal column as a reflux stream;
removing a hydrocarbon contaminant stream from the bottom of the contaminant removal column, wherein the hydrocarbon contaminant stream is a hydrocarbon rich stream;
combining the hydrocarbon rich stream with a liquefied subcooled natural gas stream to be used as a liquid natural gas product, wherein the liquefied subcooled natural gas stream is formed by indirect heat exchange of a natural gas feed stream against the refrigerant stream in a liquefier heat exchanger;
removing a vapor stream enriched in nitrogen from the top of the contaminant removal column; and
introducing the vapor stream enriched in nitrogen back into the reverse Brayton cycle refrigerant system, wherein the vapor stream enriched in nitrogen is purified in the contaminant removal column for further use as a refrigerant.

5. The method of claim 4 , wherein the method is performed on a Floating Production Storage and Offloading vessel.

6. The method of claim 4 , further comprising removing at least a portion of said liquefied portion of the refrigerant stream comprising nitrogen from the reverse Brayton cycle refrigerant system and storing the removed portion.

7. The method of claim 1 , further comprising introducing a portion of a natural gas feed stream into the bottom of the contaminant removal column to provide vapor traffic for the contaminate removal column.

8. The method of claim 4 , further comprising introducing a portion of a natural gas feed stream into the bottom of the contaminant removal column to provide vapor traffic for the contaminate removal column.

9. The method of claim 1 , wherein any portion of the natural gas stream that is introduced into the contaminant removal column is introduced solely into the bottom of the column to provide vapor traffic of the contaminant removal column.

Assignees

• Roberts Mark Julian
• Brostow Adam Adrian
• Air Prod & Chem

Inventors

• Roberts Mark Julian
• Brostow Adam Adrian

Classifications

• F25J1/025

  Details related to the refrigerant production or treatment, e.g. make-up supply from feed gas itself · CPC title

• F25J2210/06

  Splitting of the feed stream, e.g. for treating or cooling in different ways · CPC title

• F25J2220/44

  Separating high boiling, i.e. less volatile components from nitrogen, e.g. CO, Ar, O2, hydrocarbons · CPC title

• F25J1/0279

  Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc. · CPC title

• F25J1/0204

  as a single flow SCR cycle · CPC title