Method and apparatus for providing uniformity of vapour and liquid phases in a mixed stream

1. A method of providing uniformity of vapour and liquid phases in two or more streams derived from a mixed vapour and liquid stream comprising the steps of:

(a) passing the mixed vapour and liquid stream from a first heat exchanger into a distribution vessel via one or more distribution vessel inlets, the distribution vessel having two or more distribution vessel outlets connected to a second heat exchanger;

(b) allowing the liquid part of the mixed stream to collect in a first area in the distribution vessel;

(c) allowing the vapour part of the mixed stream to collect in a second area of the distribution vessel;

(d) passing the liquid in the first area into the distribution vessel outlets via one or more liquid apertures in each distribution vessel outlet communicating with the first area; and

(e) passing the vapour in the second area into the distribution vessel outlets via one or more vapour apertures in each distribution vessel outlet communicating with the second area.

2. A method as claimed in claim 1 , wherein the mixed vapour and liquid stream is a refrigerant stream.

3. A method as claimed in claim 1 , wherein the mixed vapour and liquid stream is a hydrocarbon stream.

4. A method as claimed in claim 1 , wherein the one or more distribution vessel inlets, the two or more distribution vessel outlets and the distribution vessel provide vertical flow of the streams therethrough.

5. A method as claimed in claim 1 , wherein the distribution vessel is below the provision of the mixed vapour and liquid stream from the first heat exchanger.

6. A method as claimed in claim 1 , wherein the first and second heat exchangers cool a hydrocarbon stream.

7. A method as claimed in claim 1 , wherein the first and second heat exchangers are shell-and-tube heat exchangers.

8. A method as claimed in claim 1 , wherein the distribution vessel has one distribution vessel inlet at or near the top of the distribution vessel.

9. A method as claimed in claim 1 , wherein the distribution vessel has 2 to 20 distribution vessel outlets.

10. A method as claimed in claim 1 , wherein each distribution vessel outlet extends upwardly through the distribution vessel, and at least one liquid aperture is located in the side of each distribution vessel outlet near the base of the distribution vessel.

11. A method as claimed in claim 1 , wherein each distribution vessel outlet has an end in the distribution vessel, which end is open ended to act as a vapour aperture.

12. A method as claimed in claim 1 , wherein the end of each distribution vessel outlet in the distribution vessel has a spaced end cap thereover.

13. A method as claimed in claim 1 , wherein the distribution vessel includes a baffle plate near the or each distribution vessel inlet to help distribute the mixed vapour and liquid stream from the or each distribution vessel inlet across or around the distribution vessel.

14. A method of cooling a hydrocarbon stream, the method at least comprising the steps of:

(i) passing the hydrocarbon stream through a cooling stage involving two or more heat exchangers, between which heat exchangers a mixed vapour and liquid stream passes; and

(ii) using the method as defined in claim 1 , wherein the distribution vessel is provided in the path of the mixed vapour and liquid stream between the heat exchangers.

15. A method as claimed in claim 14 , for liquefying a hydrocarbon stream to provide a liquefied hydrocarbon stream.

16. A method as claimed in claim 1 , wherein the second area of the distribution vessel is above the first area of the step (b).

17. Apparatus for providing uniformity of vapour and liquid phases in two or more streams derived from a mixed vapour and liquid stream, the apparatus at least comprising:

a distribution vessel having one or more distribution vessel inlets and two or more distribution vessel outlets, said one or more distribution vessel inlets connected to one or more outlets of a first heat exchanger, and said two or more distribution vessel outlets connected to one or more inlets of a second heat exchanger;

a first area in the distribution vessel to collect the liquid part of the mixed stream;

a second area in the distribution vessel to collect the vapour part of the mixed stream;

one or more liquid apertures in each outlet communicating with the first area, through which the liquid part of the mixed stream can pass; and

one or more vapour apertures in each outlet communicating with the second area through which the vapour part of the mixed stream can pass.

18. Apparatus as claimed in claim 17 , wherein said second area is above the first area.

19. A method of cooling a hydrocarbon stream, the method at least comprising the steps of:

(i) passing the hydrocarbon stream through a cooling stage involving two or more heat exchangers, between which heat exchangers a mixed vapour and liquid stream passes; and

(ii) using the apparatus as defined in claim 17 , wherein the distribution vessel is provided in the path of the mixed vapour and liquid stream between the heat exchangers.