Method and apparatus for cooling a hydrocarbon stream

Patent metadata

Field	Value
Publication number	US-9273899-B2
Application number	US-44485207-A
Country	US
Kind code	B2
Filing date	Oct 11, 2007
Priority date	Oct 11, 2006
Publication date	Mar 1, 2016
Grant date	Mar 1, 2016

Abstract

A hydrocarbon stream ( 30 ), such as natural gas, is commonly cooled together with a first refrigerant stream ( 140 ), against an evaporating refrigerant ( 24 ) in a series of one or more consecutively arranged common heat exchangers ( 2 ), which comprises a first common heat exchanger, upstream of which first common heat exchanger the hydrocarbon stream ( 10 ) and the first refrigerant stream ( 130 ) are not commonly cooled ( 4, 3 ). The hydrocarbon stream to be cooled is fed into the first common heat exchanger at a hydrocarbon feeding temperature, while the first refrigerant stream is fed into the first common heat exchanger at a refrigerant feeding temperature. The temperature difference between the hydrocarbon feeding temperature and the refrigerant feeding temperature is lower than 60 C.

First claim

What is claimed is:

1. Method for cooling a hydrocarbon stream, wherein the hydrocarbon stream and a first refrigerant stream are commonly cooled against an evaporating refrigerant in a series of one or more consecutively arranged common heat exchangers, which series comprises a first common heat exchanger, upstream of which first common heat exchanger the hydrocarbon stream and the first refrigerant stream are not commonly cooled, the method at least comprising the steps of:
(a) compressing a first refrigerant stream to obtain a compressed first refrigerant stream;
(b) cooling the compressed first refrigerant stream against ambient to a refrigerant temperature;
(c) receiving a hydrocarbon stream to be cooled at a starting temperature that is lower than the refrigerant temperature;
(d) feeding the hydrocarbon stream into the first common heat exchanger at a hydrocarbon feeding temperature that is lower than the refrigerant temperature;
(e) further lowering the temperature of the first refrigerant stream, after said cooling of step (b), by heat exchanging against a medium different from ambient;
(f) feeding the first refrigerant stream into the first common heat exchanger, after said heat exchanging of step (e), at a refrigerant feeding temperature, wherein the refrigerant feeding temperature is lower than the refrigerant temperature, and wherein the temperature difference between the hydrocarbon feeding temperature and the refrigerant feeding temperature is lower than 60° C.;
(g) commonly cooling the hydrocarbon stream and the first refrigerant stream against an evaporating refrigerant in the series of one or more consecutively arranged common heat exchangers
wherein said medium different from ambient comprises the hydrocarbon stream received in step (c) prior to said feeding of the hydrocarbon stream into the first common heat exchanger in step (d).

2. Method according to claim 1 , wherein said temperature difference is lower than 5° C.

3. Method according to claim 2 , wherein the hydrocarbon feeding temperature and the refrigerant feeding temperature are substantially the same.

4. Method according to claim 1 , wherein said temperature difference is smaller than an initial temperature difference between said starting temperature and said refrigerant temperature.

5. Method according to claim 1 , comprising:
(h) removing the hydrocarbon stream from the series of one or more consecutively arranged common heat exchangers as a cooled hydrocarbon stream.

6. Method according to claim 5 comprising:
(i) further cooling the cooled hydrocarbon stream removed in step (h) in at least a second heat exchanger thereby obtaining a liquefied hydrocarbon stream.

7. Method according to claim 1 , further comprising feeding a second refrigerant into the first common heat exchanger.

8. Method according to claim 7 , wherein in addition to the first refrigerant stream and hydrocarbon stream, also the second refrigerant is commonly cooled in step (g).

9. Method according to claim 7 , wherein, before feeding the second refrigerant into the first common heat exchanger, the second refrigerant stream is compressed to obtain a compressed second refrigerant stream, cooled against ambient, and further cooled by heat exchanging against a medium different from ambient.

10. Method according to claim 1 , wherein said commonly cooling the hydrocarbon stream and the first refrigerant stream against an evaporating refrigerant comprises:
removing the first refrigerant from the first common heat exchanger;
expanding it; and
returning it to the first common heat exchanger while allowing the expanded first refrigerant to at least partially evaporate in the first common heat exchanger thereby withdrawing heat from the hydrocarbon stream and at least the first refrigerant stream.

11. Apparatus for cooling a hydrocarbon stream, the apparatus comprising:
a first refrigerant stream;
a compressor arranged to compress the first refrigerant stream to obtain a compressed first refrigerant stream;
an ambient cooler arranged to cool the compressed first refrigerant stream against ambient to a refrigerant temperature;
a pre-cooling heat exchanger arranged to receive the cooled compressed first refrigerant stream and to further lower the temperature of the first refrigerant stream by heat exchanging against a medium different from ambient;
a hydrocarbon source arranged to provide a hydrocarbon stream to be cooled at a starting temperature that is lower than the refrigerant temperature;
a series of one or more consecutively arranged common heat exchangers arranged to receive and commonly cool at least the hydrocarbon stream and the first refrigerant stream, which series comprises a first common heat exchanger, such that upstream of which first common heat exchanger there is no other common heat exchanger wherein the hydrocarbon stream and the first refrigerant stream can be commonly cooled;
a hydrocarbon inlet on the first common heat exchanger arranged to receive the hydrocarbon stream at a hydrocarbon feeding temperature lower than the refrigerant temperature;
a first refrigerant inlet on the first common heat exchanger arranged to receive the first refrigerant from the pre-cooling heat exchanger at a refrigerant feeding temperature that is lower than the refrigerant temperature, and such that the temperature difference between the hydrocarbon feeding temperature and the refrigerant feeding temperature is lower than 60° C.,
wherein said medium different from ambient comprises the hydrocarbon stream between the hydrocarbon source and the hydrocarbon inlet on the first common heat exchanger.

12. Apparatus as claimed in claim 11 , further comprising a second heat exchanger for further cooling the cooled hydrocarbon stream removed from the series of common heat exchangers, thereby obtaining a liquefied hydrocarbon stream.

13. Apparatus as claimed in claim 12 , further comprising a second refrigerant being commonly cooled in the series of common heat exchangers.

14. Apparatus as claimed in claim 11 , wherein the first common heat exchanger comprises an inlet and an outlet for the first refrigerant and an inlet for an expanded first refrigerant, the apparatus further comprising an expander for expanding the first refrigerant between the outlet for the first refrigerant and the inlet for the expanded first refrigerant.

15. Method according to claim 1 , wherein the hydrocarbon stream comprises natural gas.

Assignees

• Kevenaar Mark Antonius
• Pek Johan Jan Barend
• Poh Chun Kit
• Shell Oil Co

Inventors

• Kevenaar Mark Antonius
• Pek Johan Jan Barend
• Poh Chun Kit

Classifications

• F25J1/0254

  controlling particular process parameter, e.g. pressure, temperature · CPC title

• F25J1/0214

  as a dual level refrigeration cascade with at least one MCR cycle · CPC title

• F25J1/0265

  comprising cores associated exclusively with the cooling of a refrigerant stream, e.g. for auto-refrigeration or economizer · CPC title

• F25J1/02

  requiring the use of refrigeration, e.g. of helium or hydrogen {; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process} · CPC title

• F25J1/0292

  Refrigerant compression by cold or cryogenic suction of the refrigerant gas · CPC title