ISO-pressure open refrigeration NGL recovery

Patent metadata

Field	Value
Publication number	US-9291387-B2
Application number	US-201313858585-A
Country	US
Kind code	B2
Filing date	Apr 8, 2013
Priority date	May 16, 2008
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

The present invention relates to an improved process for recovery of natural gas liquids from a natural gas feed stream. The process runs at a constant pressure with no intentional reduction in pressure. An open loop mixed refrigerant is used to provide process cooling and to provide a reflux stream for the distillation column used to recover the natural gas liquids. The processes may be used to recover C 3 + hydrocarbons from natural gas, or to recover C 2 + hydrocarbons from natural gas.

First claim

What is claimed is:

1. An apparatus for separating natural gas liquids from a feed gas stream, the apparatus comprising:
(a) a heat exchanger operable to provide the heating and cooling necessary for separation of natural gas liquids from a feed gas stream by heat exchange contact between the feed gas stream and one or more process streams;
(b) a distillation column for receiving the feed gas stream directly from the heat exchanger and separating the feed gas stream into a column overhead stream comprising a substantial amount of the lighter hydrocarbon components of the feed gas stream and a column bottoms stream comprising a substantial amount of the heavier hydrocarbon components;
(c) a separator for receiving the distillation column overhead stream and separating the column overhead stream into an overhead sales gas stream and a bottoms stream comprising a mixed refrigerant for providing process cooling in the heat exchanger;
(d) a compressor for compressing the mixed refrigerant stream after the mixed refrigerant stream has provided process cooling in the heat exchanger; and
(e) a line for passing the compressed mixed refrigerant stream to the distillation column as a reflux stream.

2. The apparatus of claim 1 , wherein the line for passing the compressed mixed refrigerant stream to the distillation column as a reflux stream goes to the heat exchanger to cool the compressed mixed refrigerant steam, prior to going to the distillation column.

3. The apparatus of claim 1 , wherein the separator is a separator drum.

4. An apparatus for separating natural gas liquids from a feed gas stream, the apparatus comprising:
(a) a heat exchanger operable to provide the heating and cooling necessary for separation of natural gas liquids from a feed gas stream by heat exchange contact between the feed gas stream and one or more process streams;
(b) a distillation column for receiving the feed gas stream and separating the feed gas stream into a column overhead stream comprising a substantial amount of the lighter hydrocarbon components of the feed gas stream and a column bottoms stream comprising a substantial amount of the heavier hydrocarbon components;
(c) a separator for receiving the distillation column overhead stream and separating the column overhead stream into an overhead sales gas stream and a bottoms stream comprising a mixed refrigerant;
(d) a first line configured to pass the mixed refrigerant stream through the heat exchanger to provide process cooling and to vaporize the mixed refrigerant, and
(e) a second line configured to pass the vaporized mixed refrigerant stream through the heat exchanger to provide process heating, at least partially liquefying the mixed refrigerant stream, and to subsequently pass the at least partially liquefied mixed refrigerant stream to the distillation column as a reflux stream.

5. The apparatus of claim 4 , wherein the separator is a separator drum.

6. A process for separating natural gas liquids from a feed gas stream, the process comprising:
(a) cooling the feed gas stream in a heat exchanger by heat exchange contact between the feed gas stream and one or more process streams to give a cooled feed gas stream;
(b) providing the cooled feed gas stream from the heat exchanger to a distillation column and separating the feed gas stream into a column overhead stream comprising a substantial amount of the lighter hydrocarbon components of the feed gas stream and a column bottoms stream comprising a substantial amount of the heavier hydrocarbon components;
(c) providing the distillation column overhead stream to a first separator and separating the distillation column overhead stream into an overhead sales gas stream and a bottoms stream comprising a mixed refrigerant;
(d) providing the mixed refrigerant to the heat exchanger as a process stream for cooling, vaporizing the mixed refrigerant stream;
(e) providing the vaporized mixed refrigerant stream to the heat exchanger as a process stream for heating, at least partially liquefying the mixed refrigerant stream, and
(f) providing the at least partially liquefied mixed refrigerant stream from the heat exchanger to the distillation column as a reflux stream.

7. A process for separating natural gas liquids from a feed gas stream the process comprising:
(a) cooling the feed gas stream in a heat exchanger by heat exchange contact between the feed gas stream and one or more process streams to give a cooled feed gas stream;
(b) providing the cooled feed gas stream from the heat exchanger to a distillation column and separating the feed gas stream into a column overhead stream comprising a substantial amount of the lighter hydrocarbon components of the feed gas stream and a column bottoms stream comprising a substantial amount of the heavier hydrocarbon components;
(c) providing the distillation column overhead stream to a first separator and separating the distillation column overhead stream into an overhead sales gas stream and a bottoms stream comprising a mixed refrigerant;
(d) providing the mixed refrigerant to the heat exchanger as a process stream for cooling, vaporizing the mixed refrigerant stream; and
(e) providing the vaporized mixed refrigerant stream to the heat exchanger as a process stream for heating, at least partially liquefying the mixed refrigerant stream,
(f) providing the at least partially liquefied mixed refrigerant stream from the heat exchanger to the distillation column as a reflux stream, and
(g) compressing and cooling the mixed refrigerant stream after the mixed refrigerant stream has provided process cooling in the heat exchanger prior to providing the mixed refrigerant stream from the heat exchanger to the distillation column as a reflux stream.

Assignees

• Lummus Technology Inc

Inventors

• Malsam Michael

Classifications

• F25J3/0233

  separation of CnHm with 1 carbon atom or more · CPC title

• F25J3/0238

  separation of CnHm with 2 carbon atoms or more · CPC title

• F25J2270/02

  Internal refrigeration with liquid vaporising loop · CPC title

• F25J2200/74

  Refluxing the column with at least a part of the partially condensed overhead gas · CPC title

• F25J2205/02

  using simple phase separation in a vessel or drum · CPC title