Process for compressing aqueous oxygen-containing stream

Abstract

The invention provides a method of compressing an aqueous oxygen-containing stream originating from an electrolysis cell, the method comprising at least the steps of: (a) providing an aqueous oxygen-containing stream (10); (b) combining the aqueous oxygen-containing stream (10) provided in step (a) as a suction fluid with an aqueous stream (20) as a motive fluid in an ejector (2), thereby obtaining a combined stream; (c) flashing the combined stream through the ejector (2), thereby obtaining a two-phase fluid (30) exiting the ejector (2); (d) separating the two-phase fluid (30) exiting the injector (2) into an oxygen-containing gas stream (40) and a liquid stream (50); (e) pressurizing the liquid stream (40) obtained in step (d), thereby obtaining a pressurized liquid stream; (f) using the pressurized liquid stream obtained in step (e) as the motive fluid (20) in step (b); (g) dehydrogenating the oxygen-containing gas stream (40) obtained in step (d), thereby obtaining a dehydrogenated oxygen-containing stream (70); (h) dewatering the dehydrogenated oxygen-containing stream (70) obtained in step (g), thereby obtaining a dewatered dehydrogenated oxygen-containing stream (80); (i) compressing the dehydrated and dehydrogenated oxygen-containing stream (80) obtained in step (h), thereby obtaining a compressed oxygen-containing stream (90); and (j) using the compressed oxygen-containing stream (90) obtained in step (i), in particular in a gasifier (9).

Description

[0001] The present invention relates to a method for compressing a water-containing and oxygen-containing feed stream originating from an electrolytic cell, wherein the obtained compressed oxygen-containing feed stream is used, in particular, in a gasifier.

[0002] The compression of gaseous feed streams is known in the art. Generally, the compression of gaseous feed streams is achieved by positive displacement devices (such as reciprocating or screw compressors), which reduce the volume occupied by the gas and thus increase the pressure. This "dry" compression can also be achieved by centrifugal blowers, compressors or pumps, which use impellers to accelerate the gas and then decelerate it, thereby converting the kinetic energy of the gas into pressure. Generally, in order to achieve the required pressure increase, multistage compression and cooling between the stages are required.

[0003] The problem with multistage compressors is that they are generally associated with high capital costs due to the associated equipment, installation and high operating costs.

[0004] Another problem with conventional "dry" compression is that it cannot be used to compress, for example, a water-saturated oxygen-containing feed stream originating from an electrolytic cell. Conventional compressors cannot withstand any water in the oxygen-containing feed stream, and using such a compressor for an oxygen-containing feed stream originating from an electrolytic cell would pose a safety risk. This is because hydrogen and oxygen present in the oxygen-containing feed stream originating from an electrolytic cell can form an explosive mixture; this problem is even more serious in the case where the oxygen-containing feed stream is subsequently used in a gasifier. In addition, the presence of water may cause corrosion of the compressor / pipeline. If this results in any dust particles in the system and, due to compression, the temperature of the gas mixture increases, an ignition chain reaction may be triggered, leading to a possible fire or explosion. This can be avoided by selecting special alloy materials, but this would result in excessive costs.

[0005] The object of the present invention is to solve, minimize or at least reduce one or more of the above problems.

[0006] Another object of the present invention is to provide an alternative method for compressing a water-containing, in particular water-saturated, oxygen-containing feed stream originating from an electrolytic cell, wherein the obtained compressed oxygen-containing feed stream is used, in particular, in a gasifier.

[0007] According to the present invention, one or more of the above or other objects can be achieved by providing a method for compressing a water-containing oxygen-containing feed stream originating from an electrolytic cell, the method comprising at least the following steps:

[0008] (a) providing a water-containing oxygen-containing feed stream;

[0009] (b) combining the water-containing oxygen-containing feed stream provided in step (a) as a suction fluid with a water-containing feed stream as a motive fluid in an ejector to obtain a combined feed stream;

[0010] (c) Flash the combined stream through the ejector to obtain a two-phase fluid discharged from the ejector;

[0011] (d) Separate the two-phase fluid discharged from the ejector into an oxygen-containing gas stream and a liquid stream;

[0012] (e) Pressurize the liquid stream obtained in step (d) to obtain a pressurized liquid stream;

[0013] (f) Use the pressurized liquid stream obtained in step (e) as the motive fluid in step (b);

[0014] (g) Dehydrogenate the oxygen-containing gas stream obtained in step (d) to obtain a dehydrogenated oxygen-containing stream;

[0015] (h) Dehydrate the dehydrogenated oxygen-containing stream obtained in step (g) to obtain a dehydrated and dehydrogenated oxygen-containing stream;

[0016] (i) Compress the dehydrated and dehydrogenated oxygen-containing stream obtained in step (h) to obtain a compressed oxygen-containing stream; and

[0017] (j) Use the compressed oxygen-containing stream obtained in step (i), in particular in a gasifier.

[0018] It has surprisingly been found according to the invention that by using a water-containing (preferably water-saturated) oxygen-containing stream from an electrolyzer as the suction fluid in an ejector, a pressurized oxygen-containing gas stream can be obtained in a surprisingly simple manner without the safety problems faced in "dry compression".

[0019] Another advantage of the method according to the invention is that pressure transfer can be achieved using static equipment. Such static equipment is reliable, simple and requires less expensive construction materials. The ejector is considered static equipment and is generally associated with low capital and operating costs compared to compressors. The ejector converts the pressure energy available in the motive fluid into velocity energy, introduces the (lower pressure) suction fluid, mixes the two fluids and discharges the mixture at an intermediate pressure without using rotating or moving parts.

[0020] In this regard, it should be noted that the ejector itself has been known for decades, but no one has proposed using it to compress a water-containing oxygen-containing stream from an electrolyzer, where the compressed oxygen-containing stream is used as a product, for example, in a gasifier.

[0021] As a mere recent example, WO 2022 / 069906 A1 discloses the use of an ejector for condensing, in particular, CO2. Although WO 2022 / 069906 A1 proposes (see page 4, lines 8 - 11) using various fluids (i.e., water, methane, ethane, propane, ethylene, propylene, methanol, ethanol, acetone, nitrous oxide) as motive fluids and gases to be compressed, it does not mention using an oxygen - containing stream (usually also containing hydrogen) originating from an electrolyzer as the suction fluid in the ejector.

[0022] As another example of the use of an ejector, JP2003105577A discloses a fuel cell hybrid system that includes a gas - generating section for generating hydrogen and oxygen (using electrolysis of water) and a fuel cell section for generating electricity in the fuel cell section by using the hydrogen and / or oxygen generated in the gas - generating section.

[0023] Furthermore, WO 2020 / 035470 A1 discloses a gas - power cycle for generating electricity using an ejector. There is no mention in WO2020 / 035470 A1 of a water - containing oxygen - containing stream originating from an electrolyzer.

[0024] In step (a) of the method according to the invention, a water - containing oxygen - containing stream is provided.

[0025] The water - containing oxygen - containing stream provided in step (a) is not limited in any way (in terms of composition, temperature, pressure, etc.), as long as it contains oxygen (O2) and water (H2O) and as long as it originates from an electrolyzer.

[0026] Generally and preferably, the water - containing oxygen - containing stream provided in step (a) is a gaseous stream, and it is preferably a water - saturated stream. It may even contain some liquid water carry - overs (up to 1.0 volume %).

[0027] Preferably, the water - containing oxygen - containing stream provided in step (a) contains at least 80 mol% of O2, preferably at least 90 mol% of O2, more preferably at least 95 mol% of O2. Preferably, the water - containing oxygen - containing stream provided in step (a) contains at most 99 mol% of O2, more preferably at most 98 mol% of O2.

[0028] Furthermore, preferably, the water - containing oxygen - containing stream provided in step (a) contains 2.0 mol% to 20 mol% of H2O, preferably 3.0 mol% to 10.0 mol% of H2O.

[0029] The water - containing oxygen - containing stream provided in step (a) usually also contains hydrogen (H2). Preferably, the water - containing oxygen - containing stream provided in step (a) contains 0.3 mol% to 2.0 mol% of H2.

[0030] Preferably, the water-containing and oxygen-containing feed stream provided in step (a) has a pressure of from 0.1 bara to 2.5 bara, preferably from 0.5 bara to 1.5 bara. The pressure of the water-containing and oxygen-containing feed stream provided in step (a) may be referred to as the "first pressure".

[0031] Furthermore, preferably, the water-containing and oxygen-containing feed stream provided in step (a) has a temperature of from 20 °C to 90 °C, preferably from 40 °C to 80 °C.

[0032] If appropriate, the water-containing and oxygen-containing feed stream provided in step (a) may have been pretreated to obtain the desired composition and conditions.

[0033] In step (b) of the process according to the invention, the water-containing and oxygen-containing feed stream provided in step (a) is combined as the suction fluid with a water-containing feed stream as the motive fluid in an ejector to obtain a combined feed stream.

[0034] Since ejectors are known in the art, they will not be described in detail here. For example, ejectors are described in Perry's Chemical Engineers’ Handbook (6th Edition 1985), pages 5-21 to 5-22 and 6-31 to 6-33. Ejectors are considered static equipment and are generally associated with low capital and operating costs compared to compressors.

[0035] Preferably, the motive fluid in step (b) contains at least 80 mol% of H2O, preferably at least 90 mol%, more preferably at least 95 mol%. Generally, the motive fluid in step (b) contains at most 99 mol% of H2O. The motive fluid in step (b) may also contain some O2 and H2. Generally, the motive fluid contains < 0.5 mol% of O2.

[0036] Those skilled in the art will readily understand that the pressure of the "motive fluid" is higher than the pressure of the "suction fluid" used in the ejector. Preferably, the pressure of the motive fluid is at least 10 bar higher than the suction fluid, preferably at least 20 bar higher, more preferably at least 50 bar higher, and even more preferably at least 80 bar higher.

[0037] Preferably, the motive fluid in step (b) has a pressure in the range of from 60 bara to 300 bara, preferably from 80 bara to 200 bara. Furthermore, preferably, the motive fluid in step (b) has a temperature of from 20 °C to 70 °C, preferably from 30 °C to 50 °C.

[0038] As described above, the suction fluid (the water-containing and oxygen-containing feed stream used as the suction fluid) has a pressure of from 0.1 bara to 2.5 bara, preferably from 0.5 bara to 1.5 bara.

[0039] In step (c) of the method according to the invention, the combined streams are flash - combined by an ejector, thereby obtaining a two - phase fluid discharged from the ejector. Generally, the flash evaporation occurs in the throat of the ejector, thereby obtaining a two - phase fluid while leaving the ejector.

[0040] As a result of the flash evaporation, the pressure of the combined streams is reduced. Preferably, the two - phase fluid obtained in step (c) has a pressure of 2.0 bara to 10.0 bara, preferably 3.0 bara to 6.0 bara. The pressure of the two - phase fluid obtained in step (c) can be referred to as the "second pressure". This second pressure is higher than the "first pressure" (of the water - containing and oxygen - containing stream provided in step (a)).

[0041] In step (d) of the method according to the invention, the two - phase fluid discharged from the ejector is separated into an oxygen - containing gas stream and a liquid stream.

[0042] This separation in step (d) is not particularly limited and is generally carried out in a conventional gas / liquid separator.

[0043] The oxygen - containing gas stream obtained in step (d) (which is at an increased second pressure) will be further processed (such as dehydrogenation, dehydration, and further compression) and used as a product in, for example, a gasifier.

[0044] In step (e) of the method according to the invention, the liquid stream obtained in step (d) is pressurized, thereby obtaining a pressurized liquid stream. Those skilled in the art will readily understand that this pressurization can be carried out in many ways, such as by using a pump, in order to obtain the desired pressure for use as a motive fluid.

[0045] In step (f) of the method according to the invention, the pressurized liquid stream obtained in step (e) is used as the motive fluid in step (b).

[0046] In step (g) of the method according to the invention, the oxygen - containing gas stream obtained in step (d) is dehydrogenated, thereby obtaining a dehydrogenated oxygen - containing stream. Since those skilled in the art are familiar with dehydrogenation, it will not be discussed in detail here. The dehydrogenation can be accomplished, for example, by catalytic H2 / O2 combustion. If this catalytic H2 / O2 combustion is used, the reactor temperature is in the range of 70 °C to 150 °C.

[0047] The dehydrogenated oxygen - containing stream preferably has an H2 content of less than 1 mol%, preferably less than 10 ppm, and more preferably less than 5 ppm.

[0048] In step (h) of the method according to the invention, the dehydrogenated oxygen-containing stream obtained in step (g) is dehydrated to obtain a dehydrated and dehydrogenated oxygen-containing stream. Since dehydration is familiar to those skilled in the art, it will not be discussed in detail here. Generally, the dehydrated and dehydrogenated oxygen-containing stream contains less than 10 ppm of H2O.

[0049] In step (i) of the method according to the invention, the dehydrated and dehydrogenated oxygen-containing stream obtained in step (h) is compressed to obtain a compressed oxygen-containing stream. Generally, the compressed oxygen-containing stream has a pressure of 6 bara to 70 bara, preferably 30 bara to 60 bara.

[0050] In step (j) of the method according to the invention, the compressed oxygen-containing stream obtained in step (i) is used, in particular in a gasifier. Since those skilled in the art are familiar with gasifiers, it will not be discussed in further detail here. Suitable gasifiers are disclosed, for example, in WO 2017 / 102942 A1. Generally, the gasifier forms part of a synthesis gas and a fossil-based hydrogen production line-up, etc.

[0051] Those skilled in the art will readily understand that the method according to the invention may include additional steps. As an example, the liquid stream obtained in step (d) and / or the pressurized liquid stream obtained in step (e) may be cooled to obtain a desired temperature or for the motive fluid for step (b). Since cooling is familiar to those skilled in the art, it will not be discussed in detail here. Cooling can be carried out, for example, by a heat exchanger, for example using air or another medium.

[0052] On the other hand, the invention provides an apparatus for compressing a water-containing, in particular water-saturated, oxygen-containing stream originating from an electrolyzer, the apparatus comprising at least:

[0053] - an electrolyzer for electrolyzing a water-containing stream to obtain at least a H2-containing stream (water-containing, in particular water-saturated) and a water-containing (in particular water-saturated) oxygen-containing stream;

[0054] - an ejector for combining the water-containing oxygen-containing stream as a suction fluid with a water-containing stream as a motive fluid to obtain a combined stream and flashing the combined stream to obtain a two-phase fluid discharged from the ejector;

[0055] - a separator for separating the two-phase fluid discharged from the ejector into an oxygen-containing gas stream and a liquid stream;

[0056] - a booster, in particular a pump, for pressurizing the liquid stream to obtain a pressurized liquid stream; and

[0057] - A recirculation pipeline for recirculating at least a portion of the pressurized liquid stream as motive fluid in an ejector;

[0058] - A dehydrogenator for dehydrogenating an oxygen-containing gas stream to obtain a dehydrogenated oxygen-containing stream;

[0059] - A dehydrator for dehydrating the dehydrogenated oxygen-containing stream to obtain a dehydrated and dehydrogenated oxygen-containing stream;

[0060] - At least one compressor for compressing the dehydrated and dehydrogenated oxygen-containing stream to obtain a compressed oxygen-containing stream; and

[0061] - A vaporizer in which the compressed oxygen-containing stream is used.

[0062] For the recirculation pipeline, water can also be discharged or supplemented (if necessary, to remove or add water).

[0063] The present invention will be further illustrated below by the following non-limiting drawings. Wherein:

[0064] Figure 1 A flowchart schematically showing a part of a method for compressing a water-saturated oxygen-containing stream derived from an electrolytic cell according to the present invention;

[0065] Figure 2 A detailed view schematically showing an exemplary non-limiting embodiment of an ejector that can be used in the method according to the present invention;

[0066] Figure 3 A schematic view showing an alternative embodiment of a part of the method according to the present invention, which further includes Figure 1 a cooler downstream of the pump 4 in;

[0067] Figure 4 A schematic view showing an alternative embodiment of the method according to the present invention, which further includes Figure 1 a cooler upstream of the pump 4 in; and

[0068] Figure 5 A schematic view showing an exemplary method according to the present invention (based on Figure 3 ), and also showing a dehydrogenator, a dehydrator, a compressor, and a vaporizer.

[0069] For the purpose of description, the same reference numerals denote the same or similar components.

[0070] Figure 1 The flowchart of Figure 2is connected to the outlet of an electrolyzer (not shown) for the water-saturated oxygen-containing feed stream 10 to be used in the ejector 2. Of course, there may be a gas / liquid separator and / or a cooler between the outlet of the electrolyzer and the inlet of the ejector 2 (2b in Figure 2 ).

[0071] During operation of Figure 1 , the water-saturated oxygen-containing feed stream 10 merges with the water-containing feed stream 20 as the motive fluid in the ejector 2, thereby obtaining a merged feed stream. The merged feed stream is flashed by the ejector 2, thereby obtaining a two-phase fluid 30 discharged from the ejector 2.

[0072] A more detailed view of the ejector 2 (a non-limiting embodiment) is shown in Figure 2 and discussed below. In the ejector 2, the water-saturated oxygen-containing feed stream 10 merges with the motive fluid 20 as the suction fluid, thereby obtaining a merged feed stream ( Figure 1 not shown in Figure 2 ; "25" in

[0073] ). The merged feed stream is flashed by the ejector 2 as it exits the ejector 2, thereby obtaining a two-phase fluid 30 discharged from the ejector 2. Figure 1 not shown in Figure 3 ; see stream 60 in

[0074] The oxygen-containing gas 40 (which has an increased pressure compared to the water-saturated oxygen-containing feed stream 10) can be directed to further compression and purification (e.g., dehydrogenation, dehydration,...) before final use, for example, in a gasifier (see also Figure 5 below).

[0075] The liquid stream 50 from the gas / liquid separator 3 is pressurized in the pump 4, thereby obtaining a pressurized liquid stream that serves as the motive fluid 20 in the ejector 2.

[0076] Figure 2 shows a more detailed view of an ejector that can be used as the ejector 2 in Figure 1 .

[0077] As can be seen from Figure 2 , the ejector 2 includes an inlet 2a for the motive fluid 20, an inlet 2b for the suction fluid 10, a nozzle 2c for the motive fluid within the ejector 2, a throat 2d having a diffuser section 2e, and an outlet 2f for the fluid 30 to be discharged.

[0078] The motive fluid 20 and the suction fluid 10 are combined in the ejector 2 (just after the nozzle 2c) to form a combined stream 25. The combined stream 25 is then flashed by the throat 2d of the ejector 2, thereby obtaining a two-phase fluid 30 discharged from the outlet 2f of the ejector 2.

[0079] Figure 3 and Figure 4 An alternative embodiment of the method according to the invention is schematically shown, in which a cooler 5 is used downstream ( Figure 1 ) or upstream ( Figure 3 ) of the pump 4 in Figure 4 ). It goes without saying that the cooler can also be present both downstream and upstream of the pump 4. In the embodiments of Figure 3 and Figure 4 , the cooler 5 is in the form of an indirect heat exchanger.

[0080] In the embodiment of Figure 3 , the cooler 5 cools the pressurized liquid stream leaving the pump 4 (referred to as "45" in Figure 3 ); the cooled pressurized liquid stream from the cooler 5 is subsequently used as the motive stream 20 in the ejector 2. In addition, Figure 3 shows the presence of a discharge stream 60.

[0081] In the embodiment of Figure 4 , the cooler 5 cools the liquid stream 50 obtained in the gas / liquid separator 3 and then conveys the cooled liquid stream to the pump 4 as stream "55".

[0082] Figure 5 A flowchart of the method according to the invention is more comprehensively outlined (based on the embodiment of Figure 3 ), and also shows a dehydrogenator 6, a dehydrator 7, a compressor 8 and a vaporizer 9.

[0083] During the use of the flowchart of Figure 5 , an oxygen-containing gas stream 40 is dehydrogenated in the dehydrogenator 6, thereby obtaining a dehydrogenated oxygen-containing stream 70.

[0084] Subsequently, the dehydrogenated oxygen-containing stream 70 is dehydrated in the dehydrator 7, thereby obtaining a dehydrated and dehydrogenated oxygen-containing stream 80, which is compressed in one or more compressors 8, thereby obtaining a compressed oxygen-containing stream 90.

[0085] The compressed oxygen-containing stream 90 can be particularly used in the vaporizer 9. Examples

[0086] Example 1

[0087] Figure 3The flowchart is used to illustrate the compression of the gaseous, water-saturated, oxygen-containing feed stream originating from the electrolyzer. The composition and conditions of the fluid (i.e., gas and liquid) feed streams in the various flow lines are provided in Table 1 below.

[0088] In ejector 2, P 抽吸 is 1.1 bara, while P 排出 is 6.0 bara.

[0089] Table 1

[0090]

[0091] Discussion

[0092] As can be seen from Table 1, the method according to the invention allows for an efficient way to compress the water-saturated, oxygen-containing feed stream originating from the electrolyzer.

[0093] An important advantage of the present invention is that by using the water-saturated, oxygen-containing feed stream as the suction fluid in the ejector, a pressurized oxygen-containing gas stream can be obtained in a surprisingly simple manner without the safety issues faced in "dry compression". The pressurized oxygen-containing gas stream can then be used in the gasifier.

[0094] Those skilled in the art will readily understand that many modifications can be made without departing from the scope of the present invention. In addition, those skilled in the art will readily understand that although the present invention may have been illustrated in some cases with reference to specific combinations of features and measures, many of these features and measures are functionally independent of other features and measures given in the corresponding embodiments, such that they can be applied equally or similarly independently in other embodiments.

Claims

1. A method for compressing a water-containing and oxygen-containing feed stream from an electrolyzer, said method comprising at least the following steps: (a) Providing a water-containing and oxygen-containing feed stream (10) from an electrolyzer; (b) Combining the water-containing and oxygen-containing feed stream (10) provided in step (a) as a suction fluid with a water-containing feed stream (20) as a motive fluid in an ejector (2) to obtain a combined feed stream; (c) Flash-vaporizing the combined feed stream through the ejector (2) to obtain a two-phase fluid (30) discharged from the ejector (2); (d) Separating the two-phase fluid (30) discharged from the ejector (2) into an oxygen-containing gas feed stream (40) and a liquid feed stream (50); (e) Pressurizing the liquid feed stream (50) obtained in step (d) to obtain a pressurized liquid feed stream; (f) Using the pressurized liquid feed stream obtained in step (e) as the motive fluid (20) in step (b); (g) Dehydrogenating the oxygen-containing gas feed stream (40) obtained in step (d) to obtain a dehydrogenated oxygen-containing feed stream (70); (h) Dehydrating the dehydrogenated oxygen-containing feed stream (70) obtained in step (g) to obtain a dehydrated and dehydrogenated oxygen-containing feed stream (80); (i) Compressing the dehydrated and dehydrogenated oxygen-containing feed stream (80) obtained in step (h) to obtain a compressed oxygen-containing feed stream (90); and (j) Using the compressed oxygen-containing feed stream (90) obtained in step (i), particularly in a gasifier (9).

2. The method according to claim 1, wherein the water-containing and oxygen-containing feed stream (10) provided in step (a) contains at least 80 mol% of O2, preferably at least 90 mol% of O2, more preferably at least 95 mol% of O2.

3. The method according to claim 1 or 2, wherein the water-containing and oxygen-containing feed stream 10) provided in step (a) contains 2.0 mol% to 20 mol% of H2O, preferably 3.0 mol% to 10.0 mol% of H2O.

4. The method according to any one of claims 1 or 2, wherein the water-containing and oxygen-containing feed stream (10) provided in step (a) contains 0.3 mol% to 2.0 mol% of H2.

5. The method according to any one of the preceding claims, wherein the water-containing and oxygen-containing feed stream (10) provided in step (a) has a pressure of 0.1 bara to 2.5 bara, preferably 0.5 bara to 1.5 bara.

6. The method according to any one of the preceding claims, wherein the water-containing and oxygen-containing feed stream (10) provided in step (a) has a temperature of 20 °C to 90 °C, preferably 40 °C to 80 °C.

7. The method according to any one of the preceding claims, wherein the motive fluid (20) in step (b) contains at least 80 mol% of H2O, preferably at least 90 mol%, more preferably at least 95 mol%.

8. The method according to any one of the preceding claims, wherein the motive fluid (20) in step (b) has a pressure in the range of 60 bara to 300 bara, preferably 80 bara to 200 bara.

9. The method according to any one of the preceding claims, wherein the motive fluid (20) in step (b) has a temperature of 20 °C to 70 °C, preferably 30 °C to 50 °C.

10. The method according to any one of the preceding claims, wherein the two-phase fluid (30) obtained in step (c) has a pressure of 2.0 bara to 10.0 bara, preferably 3.0 bara to 6.0 bara.

11. An apparatus (1) for compressing a water-containing oxygenous feed stream (10) derived from an electrolytic cell, said apparatus (1) comprising at least: - an electrolytic cell for electrolyzing a water-containing feed stream to obtain at least a hydrogen-containing feed stream and a water-containing oxygenous feed stream (10); - an ejector (2) for combining the water-containing oxygenous feed stream (10) as a suction fluid with a water-containing feed stream (20) as a motive fluid to obtain a combined feed stream (25) and flashing the combined feed stream (25) to obtain a two-phase fluid (30) discharged from the ejector (2); - a separator (3) for separating the two-phase fluid (30) discharged from the ejector (2) into an oxygen-containing gas feed stream (40) and a liquid feed stream (50); - a booster (4), in particular a pump, for pressurizing the liquid feed stream (50) to obtain a pressurized liquid feed stream; - a recirculation line for recirculating at least a part of the pressurized liquid feed stream to be used as the motive fluid (20) in the ejector (2); - a dehydrogenator (6) for dehydrogenating the oxygen-containing gas feed stream (40) to obtain a dehydrogenated oxygen-containing feed stream (70); - a dehydrator (7) for dehydrating the dehydrogenated oxygen-containing feed stream (70) to obtain a dehydrated and dehydrogenated oxygen-containing feed stream (80); - at least one compressor (8) for compressing the dehydrated and dehydrogenated oxygen-containing feed stream (80) to obtain a compressed oxygen-containing feed stream (90); and - a vaporizer (9) in which the compressed oxygen-containing feed stream (90) is used.

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