PROCESS FOR SEPARATING GASES FROM GAS MIXTURES USING HYDRO FLUORO ETHER

Abstract

A process for something separating oxygen from air includes mixing the air with hydro fluoro ether in a closed vessel for a desired period of time so that the oxygen from the air is adsorbed into the hydro fluoro ether, discharging the oxygen-adsorbed hydro fluoro ether from the closed vessel, and flashing the oxygen-adsorbed hydro fluoro ether into a chamber so that so as to separate the oxygen from the hydro fluoro ether. Nitrogen is separated from the air as the oxygen is adsorbed in the hydro fluoro ether in the closed vessel. The step of flashing that includes passing the elevated pressure oxygen-adsorbed hydro fluoro ether across a restricting orifice so as to evaporate the oxygen from the hydro fluoro ether.

Claims

1. A process for separating oxygen from air, the process comprising: mixing air with hydro fluoro ether in a closed vessel for a desired period of time so that the oxygen from the air is adsorbed into the hydro fluoro ether; discharging the oxygen-adsorbed hydro fluoro ether from the closed vessel; and flashing the oxygen-adsorbed hydro fluoro ether into a chamber so as to separate the oxygen from the hydro fluoro ether.

2. The process of claim 1, further comprising: separating nitrogen from the air as the oxygen is adsorbed in the hydro fluoro ether within the closed vessel.

3. The process of claim 2, further comprising: discharging the nitrogen from the closed vessel.

4. The process of claim 1, the oxygen and the hydro fluoro ether being discharged at an elevated pressure, the step of flashing comprising: flashing the elevated-pressure oxygen-adsorbed hydro fluoro ether across a restricting orifice; and evaporating the oxygen from the flashed elevated-pressure oxygen-adsorbed hydro fluoro ether.

5. The process of claim 4, further comprising: discharging the evaporated oxygen from the chamber.

6. The process of claim 4, the oxygen-adsorbed hydro fluoro ether being at a pressure of between 14.7 and 174.7 p.s.i.a. and at a temperature of between 32 and 140 F.

7. The process of claim 4, further comprising: collecting the hydro fluoro ether in the chamber following the step of flashing; and returning the collected hydro fluoro ether to a hydro fluoro ether inlet of the closed vessel.

8. The process of claim 1, the closed vessel being a tower having packed media therein, the step of mixing comprising: circulating the air and the hydro fluoro ether throughout the packed media in the tower.

9. The process of claim 1, the step of mixing comprising: inputting the air adjacent a bottom of the closed vessel; flowing the air upwardly through the closed vessel; inputting the hydro fluoro ether adjacent the top of the closed vessel; and flowing the hydro fluoro ether downwardly in the closed vessel such that the air mixes with the hydro fluoro ether.

10. The process of claim 1, the step of mixing comprising: flowing the hydro fluoro ether concurrently with the air.

11. The process of claim 1, the step of mixing comprising: flowing the hydro fluoro ether counter currently with the air.

12. A process for generating recovering a gas from an air feedstock, the process comprising: mixing the mixing hydro fluoro ether with the air feedstock in a closed vessel; retaining the air feedstock in contact with the hydro fluoro ether for a desired period of time so that the hydro fluoro ether adsorbs a first gas component of the air feedstock so that an unabsorbed second gas component remains in the closed vessel; and collecting the unadsorbed second gas component from the closed vessel.

13. The process of claim 12, the first and second gas components having different solubilities in the hydro fluoro ether, the process further comprising: pressurizing the closed vessel to an elevated pressure; and discharging the first gas component adsorbed hydro fluoro ether into a chamber having a reduced pressure so that the first gas component is separated from the hydro fluoro ether.

14. The process of claim 13, the step pressurizing: pressurizing the closed vessel to a pressure of between 14.7 p.s.i.a. and 174.7 p.s.i.a.

15. The process of claim 12, the step of mixing and retaining being carried out simultaneously.

16. The process of claim 12, the closed vessel being a tower having packed media therein, the step of mixing comprising: circulating the air feedstock and the hydro fluoro ether throughout the packed media in the tower.

17. The process of claim 13, further comprising: discharging the first gas component from the chamber.

18. The process of claim 13, further comprising: collecting the hydro fluoro ether in the chamber after the first gas component is separated from the hydro fluoro ether; and returning the collective hydro fluoro ether to the closed vessel.

19. The process of claim 17, the step of discharging the first gas component comprising: discharging oxygen from the chamber in which the oxygen has a purity of greater than 20% by volume.

20. The process of claim 12, the second gas component being nitrogen having a purity of greater than 80% by volume.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0050] FIG. 1 is a block diagram showing the process for separating gases in accordance with the present invention.

[0051] FIG. 2 is a perspective view of an transparent view of the tower as used for the separation of gases in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0052] Referring to FIG. 1, there shown the process 10 for the separating of gases from gas mixtures. For the purposes of illustration, the gas mixture is air. The gases that are separated include an oxygen-rich gas and a nitrogen-rich gas. The oxygen-rich gas is designated herein as oxygen and the nitrogen-rich gas herein is designated as nitrogen.

[0053] In the process of the present invention, there is a closed vessel 12. Closed vessel 12 will be a tower having the configuration shown in FIG. 2 hereinafter. Initially air 14 is introduced in the closed vessel 12 adjacent to the bottom of the closed vessel 12. The air 14 will be caused to flow upwardly through the tower 12. As will be described hereinafter, the tower 12 has packed media therein so as to maximize the surface area within the interior of the tower 12. Hydro fluoro ether is introduced through line 16 into the top of the vessel 12. As such, the liquid hydro fluoro ether will flow downwardly within the closed vessel 12. The air 14 is mixed with the hydro fluoro ether for a desired period of time so that oxygen from the air is adsorbed into the hydro fluoro ether. The oxygen-adsorbed hydro fluoro ether is discharged from the closed vessel 12 through line 18. This oxygen-adsorbed hydro fluoro ether then flows through line 14 so as to be discharged into a flash chamber 20. There is a restricting orifice 22 at the end of line 18 so as to cause the oxygen-adsorbed hydro fluoro ether to be flashed within the flash chamber 20. This flashing will evaporate oxygen from the hydro fluoro ether. It can be seen that the oxygen is discharged outwardly of the flash chamber 20 along line 24. The flash chamber 20 will be operated a lower pressure than the pressure of the closed vessel 12. In particular, the closed vessel 12 will have a pressure of between 14.7 p.s.i.a. and 174.7 p.s.i.a. and will operate a temperature between 32 and 140 F. Since the flash chamber 20 operates at a lower pressure and/or higher temperature than the closed vessel 12, the oxygen will separate from the hydro fluoro ether.

[0054] In the present process 10 of the present invention, some of the oxygen-containing capacity hydro fluoro ether will deteriorate over time. Other quantities of hydro fluoro ether will be lost during the processing. As such, a hydro fluoro ether supply line 26 can be connected to the flash chamber 20 so as to replenish any lost hydro fluoro ether back to the inlet 16. This de-oxygenated hydro fluoro ether is passed from the flash chamber 20 back along the lines 26 and 16 so as to be introduced as an input to the closed chamber 12. As a result, the process provides a closed loop for the hydro fluoro ether used in the system. Since hydro fluoro ether is relatively expensive, it is desirable to minimize the loss of such hydro fluoro ether during the processing.

[0055] In FIG. 1, since the hydro fluoro ether has adsorbed the oxygen component of the air that is been introduced into the closed chamber 12, a nitrogen component will remain. This nitrogen component is discharged along line 28 at the top of the closed chamber 12.

[0056] The air and the hydro fluoro ether are circulated throughout the packed media in the closed vessel 12. In particular, this mixing is enhanced by the fact that air is input through line 14 adjacent to the bottom of the closed vessel 12 and then flows upwardly through the closed vessel 12. Reversely, the hydro fluoro ether is introduced into the closed chamber 12 adjacent to the top of the close chamber and then flows downwardly in the closed vessel 12 so that the air mixes with the hydro fluoro ether. The hydro fluoro ether can flow concurrently or counter-concurrently with the air.

[0057] It is important to note that within the concept of the present invention, the process 10 can be a process for generating or recovering a gas from an air feedstock. In particular, the air feedstock that is introduced along line 14 will be in contact with the hydro fluoro ether for a desired period of time so that the hydro fluoro ether absorbs a first gas component of the air feedstock so that an unadsorbed second gas component remains in the closed vessel. This unabsorbed second gas component can be collected from the closed vessel. With reference to FIG. 1, the first gas component is represented by oxygen and the second gas component is represented by nitrogen.

[0058] In experiments conducted with the present invention, the hydro fluoro ether flows at a rate of 5.3 gallons per minute and 40 kilograms per minute. The hydro fluoro ether contains no oxygen or nitrogen. The air inlet 14 passed 133.3 liters per minute of air. After processing, the gas outlet 28 passed 98.7 liters per minute of the nitrogen gas. This nitrogen gas included 5% oxygen and 95% nitrogen. As such, the gas passing along line 28 is nitrogen-rich gas. The adsorption tower will cause a residence time of contact between the air and the hydro fluoro ether of 30 minutes. The adsorption tower 12 has a volume of 600 liters, a diameter of 1.1 feet and a height of 22 feet. The outlet 18 from the closed vessel 12 passed had the hydro fluoro ether with 65% oxygen and 35% nitrogen. This outlet 18 passed the oxygen-adsorbed hydro fluoro ether at a rate of 46.25 grams per minute. The degassed output from the flash chamber 20 produced 62% of oxygen and 38% of nitrogen. As such, the output 28 of the flash chamber 26 is oxygen-rich. The oxygen was passed at 30.4 grams per minute and the nitrogen passed at 16.25 grams per minute. The hydro fluoro ether that passes from the flash chamber 20 along line 26 for recycling contained zero oxygen and zero nitrogen. The hydro fluoro ether flowed outwardly of the flash chamber 20 at a rate of 40 kilograms per minute. As such, tests involving the present invention showed that a nitrogen-rich gas was released from the closed vessel 12 and that an oxygen-rich gas was passed from the flash chamber 24.

[0059] It is important to note that, in the present invention, the steps of adsorbing, mixing and retaining are carried out in a closed vessel. The hydro fluoro ether is versatile, non-toxic, non-flammable and can be used in various critical industrial applications with excellent dielectric properties and a wide range of boiling points. These fluids have excellent materials compatibility and thermal stability. The hydro fluoro ether has a low global warming potential and ozone depletion potential. This gives the user an innovative and trusted solution that does not require compromise across performance, safety and sustainability.

[0060] The hydro fluoro ether fluid provides a balanced, cost-effective solution for gas separation. The hydro fluoro ether has no regulatory restrictions or phase outs, is non-chlorinated and is exempt from U.S. E.P.A. definitions for Volatile Organic Compounds, the hydro fluoro ether is nonflammable, nonconductive, non-corrosive, a low toxicity, and a high margin of worker safety. The hydro fluoro ether is a sustainable alternative to hydrochlorofluorocarbons, hydrofluorocarbons and other common industrial solvents.

[0061] FIG. 2 shows the closed vessel 12 in accordance with the present invention. It can be seen that the closed vessel 12 includes a tower 30 of a generally cylindrical nature. Supports 32 serve to maintain plate 34 and plate 36 in spaced parallel relationship to each other at the respective top and bottom of the tower 30.

[0062] The tower 30 is packed with a packing material 38. It can be seen that the packing material 38 includes a large number of inert spherical elements that are stacked upon each other within the interior of the tower 30. The use of the packing material 38 serves to increase the surface area contact between the hydro fluoro ether and the air within the interior of the tower 30.

[0063] The hydro fluoro ether can be introduced into the interior of the tower 30 through the line 16. It can be seen that the line 16 includes the return line 26 connected thereto. A suitable valve 40 can be incorporated on the lines 16 and 26 so as to control the rate of mixing of the returned hydro fluoro ether and the original hydro fluoro ether. Alternatively, line 26 can be connected to an original supply of hydro fluoro ether and line 16 could be connected as the return line. Another valve 42 controls the flow of the hydro fluoro ether into the interior of the tower 30.

[0064] The unabsorbed gas line 28 extends outwardly of the tower 30 adjacent to the plate 34. As such, line 28 will be suitable for delivery of nitrogen from the interior of the tower 30. A valve 44 is connected to the line 28 so as to control the rate of flow of the nitrogen from the interior of the tower 30. Air is introduced into the tower 30 through line 14. A valve 46 is connected the line 14 so as to control the rate of air flow into the interior of the tower 30. The mixture of oxygen and hydro fluoro ether is discharged from the tower 30 through line 18. A valve 48 is connected the line 18 so as to control the rate of the flow of the oxygen-adsorbed hydro fluoro ether through the line 18.

[0065] The process 10 of the present invention is used to separate some gas species from a mixture of gases under various pressures according to the species' molecular characteristics and solubilities in association with hydro fluoro ether materials. The present invention operates at near-ambient temperature, and operates in a significantly different manner from the prior art cryogenic distillation techniques of gas separation and the pressure swing adsorption processes. The hydro fluoro ether is used as a trap for the gas. The hydro fluoro ether preferentially adsorbs the target gas species based upon the solubility differences in the gases. The process 10 operates continuously.

[0066] The adsorption processes utilize the fact that under certain operating pressures, temperatures and gas concentrations, gases tend to be adsorbed into the liquid hydro fluoro ether based upon the specific solubilities of the individual gases in the mixture. When the pressure is reduced, the adsorbed gas is released or desorbed. This process 10 can be used to separate gases in a mixture because different gases tend to be dissolved in the hydro fluoro ether more or less strongly.

[0067] If the gas mixture is air, it is passed under pressure through the vessel containing the hydro fluoro ether so as to attract oxygen more strongly than nitrogen. A portion or all of the oxygen will be captured by the hydro fluoro ether and the remaining gas from the air that exits the vessel will be richer in nitrogen than the mixture entering the vessel. The adsorption vessel is designed such that the flows are countercurrent and that the hydro fluoro ether reaches the end of its capacity so as to adsorb oxygen at the discharge. The oxygen and the hydro fluoro ether can be regenerated by reducing the pressure so as to release the adsorbed oxygen from the hydro fluoro ether. Hydro fluoro ether is then ready for return to the adsorption tower for another cycle of adsorbing oxygen from the air.

[0068] The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the described process can be made within the scope of the present claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.