PROCESS AND APPARATUS FOR PRODUCING A PRODUCT GAS STREAM

Abstract

The invention relates to a method for generating a product gas stream (G), comprising the steps: provision of a process gas stream (P), generation of a reactive gas stream (R) from the process gas stream (P) at reduced pressure, provision of a compressed gas stream (D) and mixing the reactive gas stream (R) with the compressed gas stream (D) with formation of a product gas stream (G).

The invention further relates to an apparatus (1) for generating a product gas stream (G), comprising a discharge chamber (2), a compressed gas line (12), a reactive gas line (11), which is realized separately from the compressed gas line (12), a product gas line (13) and a mixing chamber (3), which can be brought into flow connection with the compressed gas line (12) and the reactive gas line (11) in such a way, in that, in the mixing chamber (3), the compressed gas stream (D) can be mixed with the reactive gas stream (R) to form a product gas stream (G), wherein the mixing chamber (3) can be brought into flow connection with the product gas line (13) in such a way that the product gas stream (13) can be discharged from the apparatus (1) by means of the product gas line (13).

Claims

1. Method for generating a product gas stream (G), the method comprising the following steps: a. Provision of a process gas stream (P) of a process gas, wherein at least one component of the process gas is provided by evaporating a liquid selected from water, hydrogen peroxide (H.sub.2O.sub.2), nitrous acid (HNO.sub.2), nitric acid (HNO.sub.3) or an alcohol, b. Provision of a reactive gas stream (R) by generating a reactive gas from the process gas by means of a discharge chamber (2) at reduced pressure compared with atmospheric pressure, in particular 10 mbar to 1000 mbar, c. Provision of a compressed gas stream (D) of a compressed gas, d. Mixing the reactive gas stream (R) with the compressed gas stream (D) with formation of a product gas stream (G).

2. Method according to claim 1, wherein the liquid is evaporated by means of the heat released during operation of the discharge chamber (2).

3. Method according to claim 1, wherein at least a part of the process gas stream (P) is branched off from the process gas stream (P) to provide the compressed gas stream (D).

4. Method according to claim 1, wherein a first product gas stream (G1) is formed by mixing the compressed gas stream (D) and the reactive gas stream (R) and the first product gas stream (G1) is mixed with an additive gas stream (Z) of an additive gas with formation of a second product gas stream (G2).

5. Method according to claim 4, wherein a chemical reaction takes place between a component of the first product gas stream (G1), in particular OH, and a component of the additive gas stream (Z), in particular NO.sub.2, in particular with formation of HOONO.

6. Method according to claim 1, wherein the reactive gas stream (R) is mixed with a liquid with formation of an aerosol.

7. Method according to claim 6, wherein the formed product gas stream (G) is introduced into the liquid and the liquid mixed with the product gas stream (G) is mixed again with the reactive gas stream (R).

8. Method according to claim 1, wherein the product gas stream (G) or the reactive gas stream (R) and the compressed gas stream (D) is mixed with a particle stream (A), in particular comprising an abrasive, micro- or nanoparticles.

9. Method according to claim 1, wherein by increasing or decreasing the pressure prevailing in the discharge chamber (2), a switch is made between an O.sub.3-dominated state and a NO.sub.x-dominated state of the discharge chamber (2), and wherein at a gas temperature between 20 C. and 150 C. the O.sub.3 dominated state is present at a pressure of 600 mbar to 1000 mbar and the NO.sub.x dominated state is present at a pressure of 20 mbar to 400 mbar, or at a gas temperature between 150 C. and 200 C. the O.sub.3 dominated state is present at a pressure of 800 mbar to 1000 mbar and the NO.sub.x dominated state is present at a pressure of 20 mbar to 600 mbar.

10. Product gas stream (G), in particular generated by a method according to claim 1, comprising at least 10 mg/L hydrogen peroxide (H.sub.2O.sub.2) and at least 10 mg/L nitrite (NO.sub.2.sup.), in particular at least 50 mg/L hydrogen peroxide (H.sub.2O.sub.2) and at least 50 mg/L nitrite (NO.sub.2.sup.), preferably at least 100 mg/L hydrogen peroxide (H.sub.2O.sub.2) and at least 100 mg/L nitrite (NO.sub.2.sup.).

11. Product gas stream (G) according to claim 10, having a pH value of 6.0 or less.

12. (canceled)

13. Apparatus (1) for generating a product gas stream (G), in particular by means of a method according to claim 1, comprising a discharge chamber (2) for generating a reactive gas stream (R) from a process gas stream (P), through which discharge chamber (2) the process gas stream (P) can flow, a compressed gas line (12) through which a compressed gas stream (D) of a compressed gas can flow, a reactive gas line (11) which is realized separately from the compressed gas line (12) and through which a reactive gas stream (R) of a reactive gas can flow, a product gas line (13) through which a product gas stream (G) of a product gas can flow, characterised in that the apparatus (1) comprises a mixing chamber (3) which can be brought into flow connection with the compressed gas line (12) and the reactive gas line (11) in such a way that, in the mixing chamber (3), the compressed gas stream (D) can be mixed with the reactive gas stream (R) to form a product gas stream (G), wherein the mixing chamber (3) can be brought into flow connection with the product gas line (13) in such a way that the product gas stream (13) can be discharged from the apparatus (1) by means of the product gas line (13), wherein the discharge chamber (2) is arranged cylindrically around the mixing chamber (3).

14. Apparatus according to claim 13, wherein the apparatus (1) comprises a jet pump (31), in particular comprising a nozzle (311), and wherein the jet pump (31) is arranged such that a pressure difference between the mixing chamber (3) and the reactive gas line (11) can be generated by means of the compressed gas stream (D) flowing through the jet pump (31).

15. Apparatus according to claim 13, wherein the apparatus (1) comprises a liquid container for receiving a liquid (41) which is arranged adjacent to the discharge chamber (2), so that the heat generated during operation of the discharge chamber (2) can be used to evaporate a liquid (43) located in the liquid container (41), in particular wherein the liquid container (41) can be brought into flow connection with the compressed gas line (12) and/or the discharge chamber (2), so that liquid evaporated in the liquid container (41) can be introduced into the compressed gas line (12) and/or the discharge chamber (2).

16. Apparatus according to claim 13, wherein the apparatus (1) comprises a gas washing bottle (42) which can be brought into flow connection with the discharge chamber (2), so that a process gas can be produced by means of the gas washing bottle (42) by flowing a feed gas through a liquid (43) located in the gas washing bottle (42), in particular at reduced pressure compared with atmospheric pressure.

Description

[0170] Further features and advantages of the invention are explained in the following by describing embodiments using figures.

[0171] FIG. 1 shows a schematic representation of an apparatus for generating a product gas stream according to the invention,

[0172] FIG. 2 shows a schematic representation of a further apparatus according to the invention with a discharge chamber arranged cylindrically around the mixing chamber,

[0173] FIG. 3 shows a schematic representation of a further apparatus according to the invention with a liquid container arranged adjacent to the discharge chamber,

[0174] FIG. 4 shows a schematic representation of an apparatus realized analogously to the apparatus shown in FIG. 3 with an additional heating device,

[0175] FIG. 5 shows a schematic representation of a mixing device in which the product gas is mixed with an additive gas,

[0176] FIG. 6 shows a schematic representation of a mixing chamber with a cooling device and/or a liquid container,

[0177] FIG. 7 shows a schematic representation of an apparatus according to the invention with a drying unit,

[0178] FIG. 8 shows a schematic representation of an apparatus according to the invention with a gas washing bottle,

[0179] FIG. 9 shows a schematic representation of an apparatus according to the invention with a liquid container and a liquid line,

[0180] FIG. 10 shows a schematic representation of an apparatus according to the invention analogous to FIG. 9,

[0181] FIG. 11 shows a schematic representation of a use of an apparatus according to the invention,

[0182] FIG. 12 shows a schematic representation of part of an apparatus according to the invention,

[0183] FIG. 13 shows a schematic representation of part of an apparatus according to the invention,

[0184] FIG. 14 shows a schematic representation of an apparatus according to the invention with a baffle plate and a collecting basin.

[0185] In detail, FIG. 1 shows an apparatus 1 for generating a product gas stream G according to the invention, the apparatus 1 comprising a discharge chamber 2 for generating a plasma, a reactive gas line 11, a compressed gas line 12, a tubular mixing chamber 3 and a product gas line 13. The discharge chamber 2 is in flow connection with the mixing chamber 3 by means of the reactive gas line 11, wherein the reactive gas line 11 opens into the mixing chamber 3 at an opening 32. The mixing chamber 3 is furthermore in flow connection with the compressed gas line 12 and the product gas line 13. As an alternative to the shown arrangement, the flow connections mentioned can be closed, for example by means of valves, and opened as required.

[0186] In the shown embodiment, the discharge chamber 2 is shaped as a discharge tube, but other embodiments are also possible. The discharge chamber 2 comprises a first electrode 21 and a second electrode 22, wherein a DC voltage or an AC voltage can be generated between the first electrode 21 and the second electrode 22 by means of a voltage source 23. Alternatively, more than two electrodes can be used. By means of the voltage, a plasma and/or a reactive gas can be formed from the process gas flowing through the discharge chamber 2.

[0187] The mixing chamber 3 comprises a jet pump 31, wherein the jet pump 31 is arranged in proximity to the opening 32. The shown jet pump 31 comprises a nozzle 311 which can in particular be realized as a Venturi nozzle or a Laval nozzle.

[0188] FIG. 1 further shows a liquid container 41 filled with a liquid 43 and a heating device 5 for heating the liquid 43 contained in the liquid container 41. The shown liquid container 41 is connected to the discharge chamber 2 via a process gas line 14 so that a flow connection is formed between the liquid container 41 and the discharge chamber 2 by means of the process gas line 14. By means of the heating device 5, liquid 43 contained in the liquid container 41 is evaporated, resulting in a process gas. A process gas stream P of the process gas flows through the process gas line 14 into discharge chamber 2, where the process gas is converted into a reactive gas.

[0189] By means of the compressed gas line 12, a compressed gas stream D of a compressed gas is introduced into the mixing chamber 3 and flows through the jet pump 31, wherein a pressure difference is generated between the mixing chamber 3 and the reactive gas line 11, In this, a lower pressure prevails in the mixing chamber 3 than in the reactive gas line 11. Due to the generated pressure difference, a reactive gas stream R of the reactive gas is produced from the discharge tube 2 into the mixing chamber 3. As a result of the pressure difference, furthermore a process gas stream P of the process gas comprising evaporated liquid 43 is produced between the gaseous or vaporous upper phase of the liquid container 41 and the discharge chamber 2, flowing through the process gas line 14. Furthermore, the produced pressure difference advantageously causes liquid 43 contained in the liquid container 41 to evaporate at a lowered pressure.

[0190] The reactive gas formed in the discharge chamber 2 is sucked into the mixing chamber 3 by the pressure difference. The resulting reactive gas stream R is mixed with the compressed gas stream D in the mixing chamber 3 and forms a product gas stream G. The product gas stream G emerges from the product gas line 13 at an outlet opening 131 and can be applied to solids or liquids, for example.

[0191] FIG. 2 shows an apparatus 1 for generating a product gas stream G according to the invention, which is formed analogous to the apparatus 1 according to the invention shown in FIG. 1, with a discharge chamber 2 arranged cylindrically around the mixing chamber 3. The discharge chamber 2 is arranged at least one opening 32 of the mixing chamber 3 and can be brought into flow connection with the mixing chamber 3 by means of the at least one opening 32. In the shown apparatus, the at least one reactive gas line 11 is integrally formed with the discharge chamber 2. The cylindrical arrangement of the discharge chamber 2 around the mixing chamber 3 advantageously maximises the reactive gas stream R between the discharge chamber 2 and the mixing chamber 3 and thus optimises the mixing of the reactive gas stream R with the compressed gas stream D.

[0192] FIG. 3 shows an apparatus 1 for generating a product gas stream G according to the invention with a discharge chamber 2 arranged cylindrically around the mixing chamber 3 analogously to the apparatus 1 shown in FIG. 2. In addition, in the apparatus 1 shown in FIG. 3 the liquid container 41 is arranged cylindrically around the mixing chamber 3 and adjacent to the discharge chamber 2, so that heat which is in particular generated by the operation of the discharge chamber 2 can be transferred from the discharge chamber 2 to the liquid container 41 and the liquid 43 contained therein. By means of the transferred heat, for example, a part of the liquid 43 contained in the liquid container 41 can be evaporated, wherein in particular the discharge chamber 2 is cooled.

[0193] FIG. 4A shows an apparatus 1 for generating a product gas stream G according to the invention with a discharge chamber 2 arranged cylindrically around the mixing chamber 3 analogously to the apparatus 1 shown in FIG. 3 and a liquid container 41 arranged cylindrically adjacent to the discharge chamber 2, wherein the apparatus 1 additionally comprises a heating device 5 for heating the liquid 43 located in the liquid container 41 which is arranged adjacent to the liquid container 41.

[0194] Furthermore, FIG. 4A shows a combined pressure and process gas line 14a which can be brought into flow connection with a liquid container 41 containing liquid 43 in such a way that evaporated liquid 43 can flow through the combined pressure and process gas line 14a. In this case, the same gas stream serves both as compressed gas stream D and as process gas stream P. At a first branch 141, the combined compressed and process gas line 14a is divided into a compressed gas line 12 and a process gas line 14, wherein the compressed gas line 12 can be brought into flow connection with the mixing chamber 3, and wherein the process gas line 14 can be brought into flow connection with the discharge chamber 2. A throttle valve 142 is arranged in the process gas line 14 downstream of the first branch 141. The pressure of the process gas stream P can be throttled by means of the throttle valve 142.

[0195] FIG. 4B shows an arrangement equivalent in function to FIG. 4A, which differs in that the combined pressure and process gas line 14 a can be omitted, since a throttle valve 142 is arranged inside the liquid container 41. Here, the part of the liquid container 41 not filled with the liquid 43 is in flow connection with the mixing chamber 3 directly via the jet pump 31, so that the gas phase above the liquid 43, which in particular is under pressure, can flow through the jet pump 31 into the mixing chamber 3 as a compressed gas stream D. The gas phase, which is under pressure above the liquid 43 in particular, can flow through the jet pump 31. In addition, the gas phase located above the liquid 43 is connected to the discharge chamber 2 via the throttle valve 142, so that the gas phase can flow into the discharge chamber 2 as process gas stream P with its pressure being throttled. The upper part of the liquid container 41 serves as the compressed gas line 12.

[0196] FIG. 5 shows a mixing chamber 3 with a jet pump 31, which comprises a nozzle 311, in particular as part of an apparatus 1 for generating a product gas stream G according to invention. The mixing chamber 3 is flown through by a compressed gas stream D, which enters the mixing chamber 3 from a compressed gas line 12 which is in flow connection with the mixing chamber 3. FIG. 5 also shows a reactive gas line 11 which can be brought into flow connection with the mixing chamber 3 and through which a reactive gas stream R flows into the mixing chamber 3. In the mixing chamber 3, the reactive gas stream R is mixed with the compressed gas stream D, wherein a first product gas stream G1 is formed, which leaves the mixing chamber 3 through a product gas line 13 which can be brought into flow connection with the mixing chamber 3.

[0197] The product gas line 13 is connected at a second branch 151 with an additional gas line 15. An additional gas stream Z of an additional gas flows through the additional gas line 15, which mixes at the second branch 151 with the first product gas stream G1 with formation of a second product gas stream G2. The second product gas stream G2 leaves the apparatus 1 at the outlet opening 131.

[0198] FIG. 6A shows a mixing chamber 3 with a jet pump 31, which comprises a nozzle 311, in particular as part of an apparatus 1 for generating a product gas stream G according to invention. The mixing chamber 3 is flown through by a compressed gas stream D, which enters the mixing chamber 3 from a compressed gas line 12 which is in flow connection with the mixing chamber 3. FIG. 5 also shows a reactive gas line 11 which can be brought into flow connection with the mixing chamber 3 and through which a reactive gas stream R flows into the mixing chamber 3. In the mixing chamber 3, the reactive gas stream R is mixed with the compressed gas stream D, wherein a product gas stream G1 is formed, which leaves the mixing chamber 3 through a product gas line 13 which can be brought into flow connection with the mixing chamber 3.

[0199] In the arrangement shown in FIG. 6A, the product gas stream G leaving the mixing chamber 3 through the product gas line 13 and the outlet opening 131 is led into a liquid container 41 filled with a liquid 43. In particular, a component of the product gas can be condensed by cooling.

[0200] FIG. 6B shows a mixing chamber 3 with a jet pump 31 analogous to the mixing chamber 3 shown in FIG. 6A, in particular as part of an apparatus 1 for generating a product gas stream G according to the invention, wherein the mixing chamber 3 comprises a cooling device 6 arranged downstream with respect to the product gas stream G, in particular a cooling line, which can be brought into flow connection with the mixing chamber 3. By means of the cooling device 6, in particular a component of the product gas can be condensed by cooling.

[0201] FIG. 7 shows an apparatus 1 for generating a product gas stream G according to the invention, wherein the apparatus 1 is formed analogously to the apparatus 1 shown in FIG. 3. The apparatus 1 comprises a drying unit 7 which, with respect to the compressed gas stream D, is arranged upstream of the mixing chamber 3 and downstream of the compressed gas line 12 in flow connection with the mixing chamber 3 and the compressed gas line 12. By means of the drying unit 7, in particular the compressed gas stream D can be dried before being introduced into the mixing chamber 3.

[0202] FIG. 8 shows an apparatus 1 for generating a product gas stream G according to the invention which is formed analogously to the apparatus shown in FIG. 1 and additionally comprises a gas washing bottle 42 filled with a liquid 43 and a heating device 5 for heating the liquid 43 contained in the gas washing bottle 42. The gas washing bottle 42 comprises a feed line 421 for introducing a feed gas stream E of a feed gas into the liquid 43. The feed line 421 comprises a first valve 422 for throttling or closing the feed line 421.

[0203] Furthermore, the gas washing bottle 42 shown in FIG. 8 can be brought into flow connection with a process gas line 14. The gas wash bottle 42 also comprises a short-circuit line 423 that can be brought into flow connection with the feed line 421 and the process gas line 14, wherein the short-circuit line 423 comprises a second valve 424 for throttling and/or closing the short-circuit line 423.

[0204] FIG. 8 also shows a third valve 426 for throttling the reactive gas stream R or closing the reactive gas line 11. By simultaneously or successively closing valves 424 and 426, the negative pressure and any increased humidity in the discharge chamber 2 can be maintained without the presence of a compressed gas stream D.

[0205] The mixing chamber 3 is flown through by a compressed gas stream D, which enters the mixing chamber 3 from the compressed gas line 12. In this, a pressure difference is generated between the mixing chamber 3 and the reactive gas line 11 analogous to the apparatus 1 shown in FIG. 1, wherein a lower pressure prevails in the mixing chamber 3 than in the reactive gas line 11.

[0206] Due to the flow connection between the process gas line 14 and the gas washing bottle 42, a higher pressure also prevails in the gas washing bottle 42 than in the mixing chamber 3 when the compressed gas stream D flows through the pressurised gas line 12.

[0207] A feed gas stream E of a feed gas is introduced into the gas washing bottle 42 by means of the feed line 421, wherein the feed gas stream E is controllable by means of the first valve 422 by closing the feed line 421. The feed line 421 is arranged in such a way that if the gas washing bottle 42 is sufficiently filled with a liquid 43, the feed line 421 opens into the liquid 43, so that the feed gas stream E can be introduced into the liquid 43. In this way, the feed gas stream E can be enriched with evaporated liquid 43, forming a process gas stream P. The enrichment of the feed gas stream E with evaporated liquid 43 can be controlled by means of the short-circuit line 423 and the second valve 424. In this, the enrichment of the feed gas stream E with evaporated liquid 43 is reduced if the short-circuit line 423 is opened by means of the second valve 424.

[0208] The formed process gas stream P is then led into the discharge chamber 2 by means of the process gas line 14, analogous to the apparatus 1 shown in FIG. 1, where a reactive gas is formed from the process gas, wherein a reactive gas stream R is formed. The reactive gas stream R is sucked into the mixing chamber 3 by means of the reactive gas line 11 and mixed there with the compressed gas stream D, wherein a product gas stream G is formed.

[0209] FIG. 9 shows an apparatus with a mixing chamber 3, in particular as part of an apparatus 1 for generating a product gas stream G which is configured analogously to one of the apparatuses 1 shown in the preceding figures, and a liquid container 41 for receiving a liquid 43. FIG. 9 also shows a liquid line 16, wherein one end of the liquid line 16 is arranged in the liquid container 41 in such a way that liquid 43 can be sucked into the liquid line 16. The liquid line 16 comprises a liquid valve 161, wherein the liquid line 16 can be closed by means of the liquid valve 161. The liquid line 16 can be brought into flow connection with the mixing chamber 3 via a jet pump 31, so that a liquid flow F of the liquid 43 can be introduced into the mixing chamber 3 via the liquid line 16. A compressed gas stream D flows from the compressed gas line 12 into the mixing chamber 3. In addition, a reactive gas stream R of a reactive gas, formed in particular in a discharge chamber 2, is sucked into the mixing chamber 3 via a reactive gas line 11 which opens into the mixing chamber 3.

[0210] In the mixing chamber 3 an aerosol is formed by mixing the compressed gas stream D, the reactive gas stream R and the liquid 43, wherein the aerosol, as part of a product gas stream G, is led out of the mixing chamber 3 via the product gas line 13.

[0211] FIG. 10 shows an apparatus analogous to the apparatus shown in FIG. 9, in particular as part of an apparatus 1 for generating a product gas stream G analogous to one of the apparatuses 1 shown in the preceding figures. The product gas line 13 of the apparatus 1 is arranged above the liquid container 41 in such a way that the product gas stream G emerging from the outlet opening 131 of the product gas line 13 can be introduced into the liquid 43. In this, reactive gas is added to the liquid 43. Subsequently, a liquid flow F of the liquid 43 is introduced again into the mixing chamber 3 via the liquid line 16 and the jet pump 31 and mixed with the compressed gas stream D and the reactive gas stream R. This increases the concentration of reactive atoms and/or molecules in the formed aerosol.

[0212] FIG. 11 shows the use of an apparatus analogous to the apparatus shown in FIG. 10. First, a product gas stream G with an aerosol containing reactive atoms and/or molecules is generated by introducing a liquid 43 via the jet pump 31 into the mixing chamber 3 (FIG. 11A). Subsequently, the product gas stream G is applied to a target object 8 (FIG. 11B).

[0213] FIG. 12 shows a part of an apparatus 1 configured analogously to one of the apparatuses 1 shown in the FIGS. 1 to 10, wherein the apparatus 1 additionally comprises a particle line 17 opening into the mixing chamber 3 for transporting particles, in particular an abrasive or microparticles or nanoparticles. By means of the particle line 17, a particle stream A of particles can be introduced into the mixing chamber 3, wherein the particle stream A is mixed with the compressed gas stream D and the reactive gas stream R, wherein a product gas stream G comprising particles is formed.

[0214] FIG. 13 shows a detailed view of a part of an apparatus 1 according to the invention with a mixing chamber 3, a compressed gas line 12 that can be brought into flow connection with the mixing chamber 3 and a discharge chamber 2 arranged cylindrically around the compressed gas line 12.

[0215] The mixing chamber 3 comprises a jet pump 31 with a nozzle 311 and a diffuser 33 which is arranged downstream of the nozzle 311 and which can be brought into flow connection with the product gas line 13.

[0216] FIG. 13 further shows two reactive gas lines 11, each representing a flow connection between the discharge chamber 2 and the mixing chamber 3. The outer wall of the discharge chamber 2 forms a first electrode 21 and the inner wall of the discharge chamber 2 forms a second electrode 22. A voltage can be generated between the first electrode 21 and the second electrode 22, by means of which a discharge is caused in the discharge chamber 2.

[0217] From the compressed gas line 12 a compressed gas stream D flows into the mixing chamber 3 and from the process gas line 14 a process gas stream P flows into the discharge chamber 2, where a reactive gas is formed from the process gas. In the example shown, the compressed gas stream D and the process gas stream P run in parallel directions.

[0218] By means of the compressed gas stream D flowing through the nozzle 311, a negative pressure is generated in the mixing chamber 3 with respect to the discharge chamber 2 and/or the reactive gas lines 11, so that the reactive gas stream R from the discharge chamber 2 enters the mixing chamber 3 through at least one opening 32.

[0219] As a result, the compressed gas stream D and the reactive gas stream R are mixed in the mixing chamber 3 to form a product gas stream G. The pressure of the product gas stream G is increased as it flows through the diffuser 33, wherein simultaneously the flow velocity is reduced. From the diffuser 33 the product gas stream G flows through the product gas line 13 and leaves it through the outlet opening 131.

[0220] FIG. 14 A shows an apparatus for generating a product gas stream G with a compressed gas line 12 which is connected via a jet pump 31 to a mixing chamber 3, wherein the mixing chamber 3 is furthermore in flow connection with a product gas line 13. A discharge chamber 2 for generating a reactive gas is arranged cylindrically around a part of the compressed gas line 12, the discharge chamber 2 in turn being inside a liquid container 41 arranged cylindrically around the discharge chamber 2. In the arrangement shown, the liquid container 41 is filled with a liquid 43 so that the entire discharge chamber 2 is below the liquid level. However, a smaller amount of liquid 43 may be contained in the liquid container 41 so that only a part of the discharge chamber 2 is below the liquid level. In particular, the discharge chamber 2 can be cooled by the liquid 43 during operation.

[0221] The discharge chamber 2 is connected to the gaseous or phase present as vapour above the liquid 43 via a process gas line 14, so that the upper phase can enter the discharge chamber 2 in the form of a process gas stream P, so that a reactive gas can be formed from the process gas by means of the discharge tube 2.

[0222] The composition of the phase present above the liquid 43 in the liquid container 41 can be controlled analogously to the arrangement shown in FIG. 8 via the introduction of a feed gas stream E via the feed line 421 into the liquid 43, wherein the feed line 421 can be throttled or closed by means of a first valve 422.

[0223] The discharge chamber 2 is connected to the mixing chamber 3 via a reactive gas line 11 which can be closed by a third valve 426, so that a reactive gas stream R of the reactive gas can be introduced into the mixing chamber 3. In analogy to the apparatuses described above, the pressure difference generated by the compressed gas stream D flowing through the jet pump 31 is used to introduce the reactive gas stream R into the mixing chamber 3 and to mix the flows D and R.

[0224] FIG. 14 also shows a liquid line 16 connecting the liquid container 41 with the mixing chamber 3. The liquid line 16 can be throttled or closed via a liquid valve 161. By means of the liquid line 16, liquid 43 contained in the liquid container 41 can be introduced as liquid flow F into the mixing chamber 3, where in particular the liquid flow F can be mixed with the compressed gas stream D and the reactive gas stream R in analogy to the configurations shown in FIGS. 9 and 10 with formation of a product gas stream G comprising an aerosol.

[0225] The shown apparatus 1 also comprises a baffle plate 34 which is configured to separate larger liquid droplets formed of the aerosol from the aerosol. The separated liquid 43a separated from the aerosol collects in a collecting basin 35 which is arranged cylindrically around the product gas line 13.

[0226] FIG. 14 B shows an apparatus for generating a product gas stream G formed analogously to the apparatus shown in FIG. 14 A, wherein the liquid line 16 is arranged in such a way that liquid 43 present in the collecting basin 35 is sucked in by means of the jet pump 31, flows as liquid flow F through the liquid line 16, exits into the mixing chamber 3 and mixes there with the compressed gas stream D and the reactive gas stream R with formation of an aerosol, wherein, as in the case of the apparatus shown in FIG. 14 A, larger liquid droplets can be separated from the aerosol by means of the baffle plate 34. These droplets collect in the collecting basin 35.

Example 1Generation of a Reactive Aerosol

[0227] With the following example it is shown that by igniting a plasma in an air-water vapour process gas at a pressure of 400 mbar using a jet pump (Venturi pump), a reactive aerosol can be generated which exhibits antimicrobial activity for a few minutes after its generation.

[0228] With a jet pump, a negative pressure was generated in a discharge chamber and in a gas washing bottle connected to the discharge chamber in terms of flow. In the discharge chamber a plasma was ignited by applying an alternating voltage (frequency: 30 kHz, voltage amplitude: 6 kV) to an inner electrode according to the principle of dielectrically impeded discharge. An air-water vapour process gas was generated by means of a thermally insulated gas washing bottle that could be heated with a heating plate.

[0229] After mixing the reactive gas generated by the plasma with compressed air, which was used to operate the jet pump, a product gas stream/aerosol was formed. The aerosol was collected in a beaker for further investigation. The concentration of hydrogen peroxide (H.sub.2O.sub.2) and nitrite (NO.sub.2.sup.) and the pH value of the generated aerosol were determined by means of corresponding test strips (Merck KGaA, Germany),

[0230] A measurement of the concentration of H.sub.2O.sub.2 and NO.sub.2 and the pH value directly after collecting 1 ml of the aerosol and 3 minutes after collecting the aerosol resulted in the values listed in Table 1.

TABLE-US-00001 TABLE 1 measured values H.sub.2O.sub.2/mgL.sup.1 NO.sub.2.sub./mgL.sup.1 pH directly after generation 200 40 2.5 new measurement after 3 150 below limit of detection 2.5 minutes

[0231] It can be seen from the values that after generating the aerosol, further chemical reactions take place in the liquid in which NO.sub.2.sup. and H.sub.2O.sub.2 are converted. The technical literature shows that H.sub.2O.sub.2 and NO.sub.2.sup. have an antimicrobial effect at low pH values (preferably about 2 to 4), which results at least partly from the formation of peroxynitrite (ONOOH) in the liquid. The reaction

NO.sub.2.sup.+H.sub.2O.sub.2+H.sup.+.fwdarw.ONOOH+H.sub.2O(1)

takes place, wherein the reaction product peroxynitrite is known to have an antimicrobial effect. In this experiment, water was used as the liquid to be evaporated. According to reaction equation (1), nitrous acid (by providing NO.sub.2.sup.), H.sub.2O.sub.2 or nitric acid (by lowering the pH value) can also be used to increase the reaction rate.

[0232] In all cases, a reactive product gas stream is generated in which peroxynitrite is formed for a short time, which then reacts to further products within a short time. The half-life of ONOOH is typically less than 1 s. With the method according to the invention and/or the apparatus according to the invention, particularly high concentrations of H.sub.2O.sub.2 and NO.sub.2.sup. can be achieved (up to 700 mg/L).

[0233] The known reaction coefficients for reaction (1), for example about 20 M.sup.1s.sup.1 at a pH value of 2.5, show that the half-life of the educts NO.sub.2.sup. and/or H.sub.2O.sub.2 in this case is of the order of one second. The apparatus according to the invention is capable of applying the reactive product gas stream to a treating surface before a large part of the reactive species NO.sub.2.sup. and H.sub.2O.sub.2 has already reacted with each other according to reaction (1) and is therefore no longer available for the local formation of peroxynitrite.

LIST OF REFERENCE SIGNS

[0234]

TABLE-US-00002 1 Apparatus for Generating a Product Gas Stream 11 Reactive Gas Line 12 Compressed Gas Line 13 Product Gas Line 131 Outlet Opening 14 Process Gas Line 14a Combined Pressure and Process Gas Line 141 First Branch 142 Throttle Valve 15 Additional Gas Line 151 Second Branch 16 Liquid Line 161 Liquid Valve 17 Particle Line 2 Discharge Chamber 21 First Electrode 22 Second Electrode 23 Voltage Source 3 Mixing Chamber 31 Jet Pump 311 Nozzle 32 Opening 33 Diffuser 34 Baffle Plate 35 Collecting Basin 41 Liquid Container 42 Gas Washing Bottle 421 Feed Line 422 First Valve 423 Short-Circuit Line 424 Second Valve 426 Third Valve 43 Liquid 43a Separated Liquid 5 Heating Device 6 Cooling Device 7 Drying Unit 8 Target Object P Process Gas Stream R Reactive Gas Stream D Compressed Gas Stream G Product Gas Stream G1 First Product Gas Stream Z Additional Gas Stream G2 Second Product Gas Stream F Liquid Flow E Feed Gas Stream A Particle Stream