Method and device for conversion of water into hydrogen peroxide

Abstract

In a method and device for conversion of water into hydrogen peroxide (H.sub.2O.sub.2), a corona discharge zone is generated between a first electrode (10) and a second electrode (6) one of which is insulated and another of which is not insulated and wherein a respective surface of each of the electrodes face one another. The first electrode (10) is rotated so as to induce relative rotation between the first electrode and the second electrode; and liquid water is conveyed on to a surface of the first electrode facing the second electrode close to the axis of rotation (4) of the first electrode whereby the liquid water advances outward through the corona discharge zone towards a periphery of the first electrode under the action of centrifugal force caused by rotation of the first electrode.

Claims

1. A method for conversion of water into hydrogen peroxide (H.sub.2O.sub.2), the method comprising: generating a corona discharge zone between a first electrode and a second electrode one of which is insulated and another of which is not insulated and wherein a respective surface of each of the electrodes face one another; rotating the first electrode so as to induce relative rotation between the first electrode and the second electrode; and conveying liquid water on to a surface of the first electrode facing the second electrode close to the axis of rotation of the first electrode whereby the liquid water advances outward through the corona discharge zone towards a periphery of the first electrode under the action of centrifugal force caused by rotation of the first electrode.

2. The method according to claim 1, wherein removal of H.sub.2O.sub.2 from the surface of the first electrode is accomplished through atomization of H.sub.2O.sub.2 from the edges thereof.

3. The method according to claim 2, wherein H.sub.2O.sub.2 is atomized outside the corona discharge zone.

4. The method according to claim 1, including cooling the electrodes using cooling liquid supplied to the respective surfaces of the electrodes not facing each other.

5. The method according to claim 4, wherein the liquid water discharged on to the first electrode and the cooling liquid are supplied from a common container through an external cooler.

6. The method according to claim 5, wherein the cooling liquid is returned to said container.

7. The method according to claim 4, including supplying and removing the cooling liquid for cooling the electrode to which high voltage is applied through channels made from an electrically insulating material.

8. A device for converting water into hydrogen peroxide (H.sub.2O.sub.2), the device comprising: a hollow body containing toward an upper end thereof a pair of electrodes one of which is insulated and another of which is not insulated and wherein a respective surface of each of the electrodes face one another across a gap between said surfaces such that when a high AC voltage is applied across the electrodes a corona discharge zone is generated in the gap, a first one of the electrodes being disk-shaped and concentrically fastened to an axle that is formed of electrically conductive material and is rotatably coupled to a shaft of an electric motor mounted in the upper end of the body, a second one of the electrodes being mounted on an insulator and being configured for connection thereto of a high voltage output of a AC voltage generator, an outer diameter of the first electrode being larger than an outer diameter of the second electrode, a water container in a lower end of the body, an H.sub.2O.sub.2 outlet intermediate the water container and the electrodes for removal of H.sub.2O.sub.2 outside the device, a water inlet in said hollow body for supplying water to the container, and an electrical terminal located inside the body toward the lower end thereof and configured for connecting a low voltage output of the AC voltage generator; wherein liquid water is conveyed on to a surface of the first electrode facing the second electrode close to the axis of rotation of the first electrode whereby the liquid water advances outward through the corona discharge zone towards a periphery of the first electrode under the action of centrifugal force caused by rotation of the first electrode.

9. The device according to claim 8, wherein electrode cooling liquid is supplied to respective surfaces of the electrodes not facing each other.

10. The device according to claim 8, further comprising a compressor for supplying and removing cooling liquid for cooling the electrode to which high voltage is applied through channels made from an electrically insulating material.

11. The device according to claim 8, further including an external cooler for receiving water from said container and supplying cooled liquid for conversion to H.sub.2O.sub.2 as well as liquid for cooling the electrode surfaces.

12. The device according to claim 10, including channels formed of an electrically insulating material for delivery and removal of liquid for cooling the electrode to which high voltage is supplied.

13. The device according to claim 11, including channels formed of an electrically insulating material for delivery and removal of liquid for cooling the electrode to which high voltage is supplied.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In order to understand the invention and to see how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

(2) FIG. 1 illustrates schematically a device according to an embodiment of the invention for converting water to H.sub.2O.sub.2.

DETAILED DESCRIPTION OF EMBODIMENTS

(3) Referring to the FIGURE there is shown a device according to an embodiment of the invention for converting water to H.sub.2O.sub.2. The device comprises the following parts: body 1, electric motor 2 with feeding terminals 3 and axis 4, an axle 5 formed of electrically conductive material fastened to the axis 4, high potential stationary electrode 6, cooling contour 7 of electrode 6, insulator 8, a disk-shaped rotating electrode 10 with deflecting wall 11, which constitutes a first electrode, fastened to the axle 5 and in electrically conductive contact therewith, channel 12 for removal of the cooling liquid from the contour 7, outlet 13 for the cooling liquid removal from contour 7 to the liquid container 17, high AC voltage generator 14 with power supply terminals 15, low potential terminal 16 mounted in the liquid container 17, compressor 18 with impeller 19 fastened to the lower part of the axle 5, inlet 20 of the compressor 18 and its outlet 21, inlet channel 22 of the external cooler 23 connected to the outlet 20 of the compressor 18, opening 24 constituting a water inlet for liquid supply to the container 17, distribution channel 25 connected to the outlet of the external cooler 23 and channels 26, 29 and 30 for the liquid supply to the electrodes 6 and 10, collector 28 for H.sub.2O.sub.2 removal and an outlet 27 for H.sub.2O.sub.2 removal from the collector 28 outside the converter.

(4) The converter operation is as follows:

(5) H.sub.2O is supplied to the container 17 via the opening 24, to fill the container 17 to the level below the level of the bottom of the H.sub.2O.sub.2 collector 28.

(6) Then power is supplied to the motor 2 via terminals 3 and power is supplied to high AC voltage generator 14 via terminals 15.

(7) Since the high voltage output of the high AC voltage generator 14 is connected to the high potential electrode 6, which constitutes a second electrode, and the low voltage output of the generator 14 is connected to the low potential terminal 16 and is electrically coupled via the liquid in the container 17 to the electrode 10, a barrier corona discharge zone 9 is generated between the insulator 8 and the rotating electrode 10.

(8) As the motor 2 is started, the compressor 18 is activated to which liquid supply is initiated from the container 17 through the outlet 20. Rotation of the impeller 19 of the compressor 18 generates centrifugal force causing the liquid from the container 17 to flow under pressure from the outlet 21 of the compressor 18 via the channel 22 to the input of the external cooler 23.

(9) The cooled liquid flows from the output of the cooler 23 via the distribution channel 25 and the channel 30 supplied to the side of the rotating electrode 10 facing the insulator 8 to the area close to the axis of the rotating electrode 10. This liquid is distributed by the centrifugal force generated during rotation of the electrode 10 over the surface of the electrode 10 in a layer whose thickness depends on the liquid amount, the surface of the electrode 10 and its rotation velocity.

(10) The rotating liquid layer is advanced to the disk edge owing to the liquid detachment from the edges of the electrode 10, under the action of the centrifugal force this water layer is converted into small dispersed drops which fall into the container 28 where they form liquid H.sub.2O.sub.2 which is removed outside the converter via the outlet 24.

(11) Simultaneously the liquid from the container 17 is conveyed via the external cooler 23 and the channels 25 and 29 to the cooling contour 7 of the high potential electrode 6 from where it returns to the container 17 via the channel 12 and the opening 13 in the center of the body 1.

(12) At the same time the liquid from the container 17 via the cooler 23 and the channels 25 and 26 reaches also the side of the rotating electrode 10 not facing the insulator 8.

(13) The liquid is distributed over the electrode 10 owing to its rotation, cools it and returns to the container 17 because of the wall 11 which actually prevents this liquid from mixing with the liquid converted into H.sub.2O.sub.2 which reaches the container 28.

(14) Since the liquid amount in the container 17 is continually reduced by the amount of H.sub.2O.sub.2 reaching the container 28, the liquid level in the container 17 must be maintained constant during operation by an external dosimeter operating in a constant or pulsating mode. Keeping the liquid level constant during the full work cycle of the converter is a basic requirement as described, for example, in US 2017/0335471, to which further reference may be made.

(15) H.sub.2O.sub.2 can be removed from the container 28 either continuously or periodically depending on the volume of the container 28. Since the body 1 of the converter does not have air inlet and outlet openings ozone (O.sub.3) generated in the corona discharge zone 9 circulates inside the body 1 without reaching the environment.

(16) The inventors have constructed a development prototype of the converter with the following specifications:

(17) TABLE-US-00001 1. Material of insulation layer Glass 2. Distance between the electrodes 1 mm 3. The electrode rotation velocity 2000 RPM 4. The AC voltage source amplitude ±5 kV 5. The AC voltage source frequency 40 kHz 6. Water consumption 300 mL/h 7. H.sub.2O.sub.2 concentration at the converter outlet 100 ppm

(18) The concentration of H.sub.2O.sub.2 is a function of the supplied power, 95% of which is wasted as heat with only 5% contributing to the generation of H.sub.2O.sub.2. Therefore, in order to produce a high concentration of H.sub.2O.sub.2 as proposed (100 ppm), a large amount of waste heat is formed and must be dissipated. The best way to achieve this in practice is by some form of cooling as described. However, a manufacturer or end-user able to suffice with a much smaller concentration such as only 2 ppm, can reduce the power by reducing the current proportionately i.e. by a factor of 50 relative to that required for a concentration of 100 ppm. The heating effect is then significantly reduced whereby it may be possible to achieve sufficient cooling by the ambient air flow without the need for external cooling.