Systems and methods for multi-stage refrigeration

1. A multi-stage refrigeration system, comprising:

an eductor in fluid communication with a first vapor line and a liquid source;

a flashdrum in fluid communication with the eductor for receiving a two-phase fluid, the flashdrum connected to a second vapor line and a liquid line;

a first expansion valve in fluid communication with the liquid line and connected to a chilled two-phase fluid line;

another flashdrum in fluid communication with the chilled two-phase fluid line and connected to the first vapor line;

a pump positioned upstream of the eductor and in fluid communication with the liquid source;

another liquid line connected to the another flashdrum;

a second expansion valve in fluid communication with the another liquid line and connected to a third vapor line; and

another accumulator in fluid communication with the first vapor line, the second vapor line, the third vapor line and the eductor.

2. The system of claim 1 , wherein a pressure at the liquid source is higher than a pressure in the first vapor line.

3. The system of claim 2 , wherein the pressure at the liquid source is at least thirty-four times higher than the pressure in the first vapor line.

4. The system of claim 1 , wherein the liquid source comprises ethylene.

5. The system of claim 1 , wherein the liquid source comprises ethane.

6. The system of claim 1 , wherein the pressure in the first vapor line is at least four times lower than the pressure in the second vapor line.

7. A method for multi-stage refrigeration, comprising:

introducing a first liquid stream into an eductor at a pressure of at least 600 psig;

introducing a first vapor stream into the eductor to achieve partial liquefaction and produce a two-phase fluid stream comprising the first vapor stream and the liquid stream;

flashing the two-phase fluid stream to produce a second liquid stream and a second vapor stream;

expanding the second liquid stream to produce a chilled two-phase fluid stream;

flashing the chilled two-phase fluid stream to produce the first vapor stream and a third liquid stream,

retaining residual vapor from a liquid refrigerant stream; and

producing the first liquid stream.

8. The method of claim 7 , further comprising expanding the third liquid stream to produce another chilled two-phase fluid stream.

9. The method of claim 8 , further comprising retaining residual condensation from the another chilled two-phase fluid stream and producing a third vapor stream.

10. The method of claim 7 , wherein a pressure of the first vapor stream is lower than a pressure of the second vapor stream.

11. The method of claim 10 , wherein the pressure of the first vapor stream is at least four times lower than the pressure of the second vapor stream.

12. The method of claim 7 , wherein a pressure of the first liquid stream is higher than a pressure of the first vapor stream.

13. The method of claim 12 , wherein the pressure of the first liquid stream is at least thirty-four times higher than the pressure of the first vapor stream.

14. The method of claim 7 , wherein the first liquid stream comprises ethylene.

15. The method of claim 7 , wherein the liquid stream ethane.