COMPRESSION AND SEPARATION DEVICE AND COMPRESSION PROCESS

Abstract

In a compression process in a dynamic compressor having at least one first and one second compression stages, a first gas having a first molecular weight of less than 10 g/mol is compressed, at least one second fluid having a second molecular weight greater than 50 g/mol is mixed with the first gas to form a third gas to be compressed having a molecular weight greater than 10 g/mol, the third gas is sent to the first compression stage, the third gas is cooled in a first heat exchanger downstream of the first compression stage, where it is partially condensed, the partially condensed third gas is sent to a first phase separator to form a fourth gas having a lower molecular weight than the third gas and a first condensed liquid having a higher molecular weight than the third gas, the fourth gas is sent from the first phase separator to the second compression stage, the fourth gas compressed in the second compression stage is sent to cool in a second heat exchanger where it partially condenses, and the partially condensed fourth gas is sent to a second phase separator to produce a fifth gas having a lower molecular weight than the fourth gas.

Claims

1-11. (canceled)

12. A compression and separation device, comprising a dynamic compressor having first and second compression stages for compressing a first gas having a first molecular weight less than 10 g/mol: a. an inlet for the first gas; b. means for mixing at least one second fluid having a second molecular weight greater than 50 g/mol with the first gas to form a third gas to be compressed having a molecular weight greater than 10 g/mol; c. means for sending the third gas to the first compression stage, a first heat exchanger for cooling the third gas downstream of the first compression stage in order to partially condense it, a first phase separator, means for sending the partially condensed third gas to the first phase separator to form a fourth gas having a lower molecular weight than the third gas and a first condensed liquid having a higher molecular weight than the third gas; d. means for sending the fourth gas from the first phase separator to the second compression stage, a second heat exchanger downstream of the second compression stage, means for sending the compressed fourth gas to the second compression stage and cooling it in the second heat exchanger in order to partially condense it, a second phase separator and means for sending the partially condensed fourth gas to the second phase separator to produce a fifth gas having a lower molecular weight than the fourth gas and a second condensed liquid having a higher molecular weight than the fourth gas; and e. a separation device and means for sending the fifth gas or a gas derived from the fifth gas to the separation device to be separated therein to produce a gaseous product having a molecular weight of less than 10 g/mol, and a composition of less than 10 ppm of any component having a molecular weight greater than 50 g/mol.

13. The device as claimed in claim 12, comprising means for recovering the first condensed liquid and/or the second condensed liquid, and further comprising means for mixing the first and/or second condensed liquid with the first gas.

14. The device as claimed in claim 13, said means for recovering comprising a common reservoir.

15. The device as claimed in claim 13, comprising means for at least partially vaporizing the first and/or second condensed liquid and means for at least partially recycling the vaporized portion as a second fluid.

16. The device as claimed in claim 12, comprising means for using some of the heat generated by compression to vaporize the first and/or second condensed liquid.

17. The device as claimed in claim 12, in which the first and/or second phase separator is not thermally insulated from the ambient air.

18. A compression process in a dynamic compressor having at least one first and one second compression stages, the process comprising the steps of: compressing a first gas having a first molecular weight of less than 10 g/mol; mixing at least one second fluid having a second molecular weight greater than 50 g/mol with the first gas to form a third gas to be compressed having a molecular weight greater than 10 g/mol; sending the third gas to the first compression stage; cooling the third gas in a first heat exchanger downstream of the first compression stage, where the third gas is partially condensed; sending the partially condensed third gas to a first phase separator operating at a temperature greater than −50° C. to form a fourth gas having a lower molecular weight than the third gas and a first condensed liquid having a higher molecular weight than the third gas, the fourth gas is sent from the first phase separator to the second compression stage; sending the fourth gas compressed in the second compression stage to cool in a second heat exchanger where it partially condenses; and sending the partially condensed fourth gas to a second phase separator operating at a temperature greater than −50° C. to produce a fifth gas having a lower molecular weight than the fourth gas and a second condensed liquid having a higher molecular weight than the fourth gas.

19. The process as claimed in claim 18, wherein the first condensed liquid and/or the second condensed liquid are recovered, optionally in a common reservoir, and the first and/or second condensed liquid is mixed with the first gas optionally after vaporization.

20. The process as claimed in claim 18, wherein the first and/or second condensed liquid is at least partially vaporized and the vaporized portion is at least partially recycled as a second fluid.

21. The process as claimed in claim 18, wherein the first gas is hydrogen.

22. A compression and separation process comprising a compression process as claimed in one of claim 18, in which the fifth gas or a gas derived from the fifth gas is sent to a separation device to be separated therein to produce a gaseous product having a molecular weight of less than 10 g/mol, or even less than 7.5 g/mol, or even less than 5 g/mol, and a composition of less than 10 ppm, or even less than 5 ppm, or even less than 1 ppm of any component having a molecular weight greater than 50 g/mol.

23. The process as claimed in claim 22, wherein the separation device also produces a gas having a molecular weight greater than 10 g/mol, or even greater than 7.5 g/mol, or even greater than 5 g/mol, and a composition of more than 10 ppm, or even more than 5 ppm, or even more than 1 ppm of any component having a molecular weight greater than 50 g/mol, and this gas is sent upstream of the compressor to be compressed therein with the first gas.

Description

[0047] The invention will be described in more detail with reference to the figures.

[0048] FIG. 1 represents a process according to the invention.

[0049] FIG. 2 represents a process according to the invention.

[0050] In FIG. 1, a first gas having a first molecular weight less than 10 g/mol, or even less than 7.5 g/mol. or even less than 5 g/mol, for example hydrogen or helium 1, is compressed in a compressor stage C1. After being mixed with a gas 21 having a second molecular weight that is greater than 50 g/mol and optionally with a gas 25 also having a second molecular weight that is greater than 50 g/mol, it forms a gas mixture having a third molecular weight that is greater than 10 g/mol. The gas 21 can for example be dichloromethane (CH.sub.2Cl.sub.2).

[0051] The gas 21 can be replaced by a liquid. In this case, the liquid 21 is injected into the first gas in aerosol form.

[0052] The first gas has a first main component and the second fluid optionally has a second main component, in each case the main component preferably comprises 50 mol %, or even 80 mol %, or even 90 mol %, or even 95 mol % of the gas.

[0053] It can optionally also be mixed with a gas 25. The mixture 3 having a molecular weight greater than 10 g/mol, or even greater than 15 g/mol, is compressed in a dynamic compressor stage C2 to form a compressed gas 5, and the compressed gas is cooled in a cooler R1 to partially condense it. The partially condensed flow 7 is separated in a phase separator P1. The gas 9 from the phase separator P1, enriched in the first main component and optionally depleted in the second main component, is compressed in a dynamic compressor stage C3 and cooled by a cooler R2 for another partial condensation step. The partially condensed flow 10 is separated in a phase separator P2.

[0054] The gas 13 from the phase separator P2, enriched in the first main component and optionally depleted in the second main component, is separated to produce a produced gas 23 having the same main component as the first gas, being able to be as pure in this component as the first gas, more pure in this component than the first gas, or less pure in this component than the first gas. The gas 13 is enriched in the first main component and optionally depleted in the second main component compared to the gas 13 and compared to the gas 10.

[0055] The first gas 1 and the produced gas 23 contain at least 80 mol % of a first component, or even at least 90 mol %, or even at least 95 mol %.

[0056] The produced gas 23 and preferably the gas 13, or even the gas 10, have a molecular weight of less than 10 g/mol, or even less than 7.5 g/mol, or even less than 5 g/mol.

[0057] The separation of the gas 23 in the device 1 can be carried out by any suitable means, such as distillation, absorption, adsorption, permeation, scrubbing or a combination of several of these techniques.

[0058] The gas 25 produced by the device 1 contains a mixture of the first gas and the second fluid and can be recycled upstream of the compression stage C2 so that none of the two fluids is lost.

[0059] Whatever gases are mixed with the gas 1, the important aspect is that the mixture 3 entering the compression stage C2 has a higher molecular weight than the gas 1. The liquid 15 from the phase separator P2 enriched in the second main component and depleted in the first main component compared to the gas 10 is expanded and sent to a storage tank S. This storage tank also receives the expanded liquid 11 from the first phase separator P1, which is enriched in the second main component and depleted in the first main component compared to the gas 7. The two phase separators P1, P2 operate at temperatures above −50° C., or even above −20° C., or even above 0° C., or even above ambient temperature. Depending on the operating temperature, they can be exposed without insulation.

[0060] The liquid 17 from the storage tank is expanded, heated by the heater H to vaporize it and sent as gas 21 to modify the molecular weight of the gas 1. The head gas from the storage tank 19 can also be mixed downstream of the heater H.

[0061] Another possibility, shown in FIG. 2, is to incorporate the heater H into the storage tank S to vaporize the liquids 11, 15 accumulated in the storage tank S, so that only the gas 19 is recycled as gas 21 mixed with the gas 1.

[0062] Preferably, at least some of the compression heat from the first gas 1 is recovered to heat the liquid(s) 11, 15. The heater H and the coolers R1 and/or R2 can thus be connected to each other or even form part of a single heat exchanger.

[0063] The stages C2, C3 or even C1 are dynamic, or even centrifugal, compression stages.

[0064] Preferably, the storage tank S in the two figures operates at temperatures above −50° C., or even above −20° C., or even above 0° C., or even above ambient temperature. Depending on the operating temperature, it can be exposed without insulation.