Back to results
US 6,367,286 B1Granted
System and process for liquefying high pressure natural gas
AssigneeBlack & Veatch Pritchard, Inc.
InventorBrian C. Price
Life of this patent
Estimating the term…
Abstract
A system and a method for efficiently removing natural gas liquids from a natural gas stream at an elevated pressure and liquefying the natural gas stream at an elevated pressure by use of a turbo expander and a compressor.
Claims23
A process for liquefying a natural gas stream having a pressure greater than about 500 psig in a mixed refrigerant process to produce a liquefied natural gas product, the method comprising:
- a) cooling the natural gas stream in a heat exchanger in the mixed refrigerant process to a first temperature less than about −40_F. to produce a cooled natural gas stream;
- b) passing the cooled natural gas stream to a liquids separation zone to produce a first gas stream and a first liquids stream;
- c) passing the first liquids stream to a methane separation tower at a temperature less than about −40° F. and at a pressure less than about 650 psig to produce a second gas stream comprising methane and a second liquids stream containing natural gas liquids;
- d) passing the first gas stream to a turbo expander to reduce the pressure of the first gas stream to a pressure less than about 650 psig to produce a reduced pressure gas stream and passing the reduced pressure gas stream to the methane separation vessel;
- e) driving a compressor with the turbo expander;
- f) passing the second gas stream to the compressor and compressing the second gas stream to a pressure of at least about 500 psig to produce a compressed gas stream;
- and,
- g) passing the compressed gas stream to the heat exchanger for liquefaction at a pressure of at least about 500 psig to produce the liquefied natural gas.
5 more elements
A process for liquefying a natural gas stream having a pressure greater than about 500 psig in a natural gas liquefaction process to produce a liquefied natural gas product, the process comprising:
- a) cooling the natural gas stream in a heat exchanger in the natural gas liquefaction process to a first temperature less than about −40° F. to produce a cooled natural gas stream;
- b) passing the cooled natural gas stream to a liquids separation zone to produce a first gas stream and a first liquids stream;
- c) passing the first liquids stream to a methane separation tower at a temperature less than about −40° F. and at a pressure less than about 650 psig to produce a second gas stream comprising methane and a second liquids stream containing natural gas liquids;
- d) passing the first gas stream to a turbo expander to reduce the pressure of the first gas stream to a pressure less than about 650 psig to produce a reduced pressure gas stream and passing the reduced pressure gas stream to the methane separation tower;
- e) driving a compressor with the turbo expander;
- f) passing the second gas stream to the compressor and compressing the second gas stream to a pressure of at least about 500 psig to produce a compressed gas stream;
- and,
- g) passing the compressed gas stream to the heat exchanger for liquefaction at a pressure of at least about 500 psig to produce the liquefied natural gas.
5 more elements
A system for liquefying a natural gas stream having a pressure greater than about 500 psig, the system comprising:
- a) a refrigeration unit adapted to cool the natural gas to a temperature sufficient to liquefy at least a major portion of the natural gas, the refrigeration unit having an intermediate gas outlet, an intermediate gas inlet and a product liquefied natural gas outlet;
- b) a separator in fluid communication with the intermediate gas outlet and having a gas outlet and a liquids outlet;
- c) a methane separator tower in fluid communication with the liquids outlet and having an overhead gas outlet, a bottom liquid outlet and a gas inlet;
- d) a turbo expander in fluid communication with the gas outlet from the separator and the gas inlet to the methane separator tower;
- and,
- e) a compressor driven by the turbo expander and in fluid communication with the overhead gas outlet and having a compressed gas outlet in fluid communication with the intermediate gas inlet.
3 more elements
A process for efficiently separating natural gas liquids from a natural gas stream at a pressure greater than about 500 psig to produce a high pressure gas stream and a natural gas liquids stream, the process comprising:
- a) cooling the natural gas stream to a first temperature less than about −40° F. to produce a cooled natural gas stream;
- b) passing the cooled natural gas stream to a liquids separation zone to produce a first gas stream and a first liquids stream;
- c) passing the first liquids stream to a methane separation vessel at a temperature less than about −40° F. and at a pressure less than about 650 psig to produce a second gas stream comprising methane and a second liquids stream containing natural gas liquids;
- d) passing the first gas stream to a turbo expander to reduce the pressure of the first gas stream to a pressure less than about 650 psig to produce a reduced pressure gas stream and passing the reduced pressure gas stream to the methane separation tower;
- e) driving a compressor with the turbo expander;
- and,
- f) passing the second gas stream to the compressor and compressing the second gas stream to produce a high pressure compressed gas stream.
4 more elements
Dependencies are inferred from the claim text.