Electric discharge device and method for treatment of fluids

Abstract

The present disclosure relates to an electric discharge device and associated method for molecular restructuring of a fluid. The electric discharge device comprises a discharge cell including a first dielectric layer and a second dielectric layer that are spaced apart by a gap constituting a flow channel for a feed fluid to be molecularly restructured. The dielectric layers and the flow channel are arranged between a first electrode and a second electrode for generating electric discharge in the flow channel when voltage is applied between the electrodes. The discharge cell comprises a double-walled dielectric tube having an inner wall and an outer wall that come together at both ends of the tube to form a double-walled dielectric tube made in one piece, the inner and outer walls of the double-walled dielectric tube constituting the first and second dielectric layers of the discharge cell.

Claims

1. An electric discharge device for molecular restructuring of a fluid, comprising a discharge cell including a first dielectric layer and a second dielectric layer that are spaced apart by a gap constituting a flow channel for a feed fluid to be molecularly restructured, the dielectric layers and the flow channel are arranged between a first electrode and a second electrode for generating electric discharge in the flow channel when voltage is applied between the electrodes, wherein the discharge cell comprises a single-piece, double-walled dielectric tube having a cylindrical inner wall that constitute the first dielectric layer, a cylindrical outer wall that constitute the second dielectric layer, at least one inlet for feeding fluid to be restructured into the flow channel, and at least one outlet for discharge of restructured fluid, wherein the cylindrical inner wall and the cylindrical outer wall come together at both ends of the dielectric tube, and wherein the at least one inlet and the at least one outlet are integrally formed in the cylindrical outer wall in opposite ends of the single-piece, double-walled dielectric tube.

2. The electric discharge device according to claim 1, wherein the first electrode comprises an inner electrode arranged on an inner side of the inner wall of the double-walled dielectric tube, and the second electrode comprises an outer electrode arranged on an outer side of the outer wall of the double-walled dielectric tube.

3. The electric discharge device according to claim 2, wherein the discharge cell is provided with a through channel extending along a center axis of the double-walled dielectric tube, and mounted in the electric discharge device such that a flow of cooling medium can flow through the through channel during use of the electric discharge device to cool the inner electrode.

4. The electric discharge device according to claim 3, further comprising a cooling device that is configured to direct a flow of a cooling medium towards an end of the discharge cell in order for the cooling medium to pass through the through channel.

5. The electric discharge device according to claim 1, wherein the cylindrical inner wall and the cylindrical outer wall define an annular flow channel for the fluid to be reconstructed.

6. The electric discharge device according to claim 5, wherein the inner and outer electrodes are formed as cylindrical shells that are concentrically arranged with respect to each other and the double-walled dielectric cylinder, the inner electrode having a diameter that is smaller than the diameter of the inner cylindrical wall, and the outer electrode having a diameter that is bigger than the diameter of the outer cylindrical wall.

7. The electric discharge device according to claim 5, wherein the at least one inlet and the at least one outlet of the flow channel are arranged on an envelope surface of the double-walled dielectric cylinder.

8. The electric discharge device according to claim 5, wherein at least one of the at least one inlet the at least one outlet of the flow channel is arranged on a side wall of the double-walled dielectric cylinder, connecting the inner wall with the outer wall.

9. The electric discharge device according to claim 1, further comprising at least one metallic catalyser layer, comprising at least one of cadmium or nickel, arranged between at least one of said first and second electrodes and at least one of said first and second dielectric layers.

10. The electric discharge device according to claim 1, further comprising a frequency modulator for adapting a driving frequency of the electric discharge device to the fluid to be restructured.

11. A vehicle comprising a combustion engine, wherein that vehicle further comprises an electric discharge device according to claim 1, wherein the electric discharge device is arranged such that fuel is fed through the flow channel of the discharge cell prior to combustion of the fuel in the combustion engine.

12. A method for molecular restructuring of a fluid, wherein the steps of: applying a voltage between the first electrode and the second electrode of the electric discharge device according claim 1, in order to generate the electric discharge in the flow channel of the discharge cell, and feeding the fluid to be restructured through the flow channel of the discharge cell.

13. The method according to claim 12, wherein the fluid to be restructured comprises oxygen-containing gas that is fed through the discharge cell to produce ozone.

14. The method according to claim 12, wherein the fluid to be restructured comprises a mixture of oxygen-containing gas and hydrogen peroxide that is fed through the discharge cell to produce a reactive mixture comprising ozone and hydroxyl radicals.

15. The method according to claim 12, wherein the fluid to be restructured comprises a vegetable oil that is fed through the flow channel of the discharge cell to produce biodiesel.

16. The method according to claim 12, wherein the fluid to be restructured is industrial process water that is fed through the flow channel of the discharge cell to purify and/or facilitate purification of the industrial process water.

17. The method according to claim 12, performed in a vehicle comprising the electric discharge device and a combustion engine, wherein the fluid to be restructured is fuel that is fed through the flow channel of the discharge cell to refine the fuel prior to combustion of the fuel by the combustion engine.

18. The method according to claim 15, wherein the vegetable oil comprises jatropha oil.

19. The method according to claim 17, wherein the fuel comprises fossil diesel or biodiesel.

20. An electric discharge device for molecular restructuring of a fluid, comprising a discharge cell including a first dielectric layer and a second dielectric layer that are spaced apart by a gap constituting a flow channel for a feed fluid to be molecularly restructured, the dielectric layers and the flow channel are arranged between a first electrode and a second electrode for generating electric discharge in the flow channel when voltage is applied between the electrodes, wherein the discharge cell comprises a single-piece, double-walled dielectric tube having a cylindrical inner wall that constitute the first dielectric layer, a cylindrical outer wall that constitute the second dielectric layer, at least one inlet for feeding fluid to be restructured into the flow channel, and at least one outlet for discharge of restructured fluid, wherein the cylindrical inner wall and the cylindrical outer wall come together at both ends of the dielectric tube by side walls of the double-walled dielectric tube, and wherein the at least one inlet and the at least one outlet are integrally formed in one of the cylindrical outer wall or the side walls, in opposite ends of the single-piece, double-walled dielectric tube.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) A more complete appreciation of the invention disclosed herein will be obtained as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings briefly described below, in which drawings the same reference numerals are used to represent corresponding functional elements.

(2) FIG. 1 illustrates an electric discharge device for molecular restructuring of a fluid, according to an exemplary embodiment of the present disclosure.

(3) FIG. 2 illustrates schematically an exemplary embodiment of a discharge cell of the electric discharge device.

(4) FIGS. 3A-3E illustrate a side view, a top view and cross-sectional views of a discharge cell according to an exemplary embodiment.

(5) FIGS. 4A-4B illustrate cross-sectional views of a discharge cell according to another exemplary embodiment.

(6) FIG. 5 illustrates a perspective view of a discharge cell according to yet another embodiment.

(7) FIG. 6 is a flowchart illustrating a method for molecular restructuring of a fluid, according to an exemplary embodiment of the present disclosure.

(8) FIGS. 7A and 7B illustrate a system and method for wastewater purification, according to exemplary embodiments of the present disclosure.

(9) FIGS. 8A and 8B illustrate a system and method for production and/or refinement of biofuel, according to exemplary embodiments of the present disclosure.

(10) FIGS. 9A and 9B illustrate a system and method for refinement of fuel in a vehicle, prior to combustion of the fuel in a combustion engine of the vehicle, according to exemplary embodiments of the present disclosure.

(11) FIGS. 10A and 10B illustrate a system and method for treatment of industrial process water, according to exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION

(12) FIG. 1 illustrates an electric discharge device 1 for molecular restructuring of a fluid according to an exemplary embodiment of the present disclosure.

(13) The electric discharge device 1 is a corona discharge device configured to crack the molecules of a fluid by subjecting the fluid to corona discharge. To this end, the electric discharge device 1 comprises a discharge cell 2 for corona discharge, and a drive circuit 3 for applying a high voltage between electrodes of the discharge cell in order to generate corona discharge.

(14) The drive circuit 3 comprises a converter 4 that is connected to a transformer 5. The converter 4 is also connected to a power supply 6, such as a mains electricity supply for delivery of about 230V alternating current (AC) at 50 or 60 Hz, a 12V direct current (DC) car battery, or a 24V or 48V DC battery. The transformer 5 comprises a primary winding 7 that is coupled to a secondary winding 8 via a transformer core 9. The secondary winding 9 is connected to a first electrode of the discharge cell via a first cable 10, and to a second electrode of the discharge cell via a second cable 11.

(15) During operation, the converter 4 generates a direct voltage which, by means of a DC switching device in the converter 4, is rapidly applied to the primary winding 7 of the transformer 5. The application of the DC voltage to the primary winding 7 generates a magnetic field that excites the secondary winding 8 of the transformer. By rapidly switching on and off the DC voltage applied to the primary winding at a driving frequency, f.sub.0, of the electric discharge device, a high voltage causing one or both of the first and second electrodes to discharge electricity through the discharge cell is applied between the first and second electrodes of the discharge cell. As well known in the art and discussed in e.g. US2002/0058000, the driving frequency, f.sub.0, of the DC voltage applied to the primary winding 7 of the transformer 5 should be adapted to a resonant frequency of the cell circuit constituted by the secondary winding 8 of the transformer 9 and the discharge cell 2. For efficient operation of the electric discharge device, the driving frequency may, e.g., be set approximately equal to the resonant frequency of the cell circuit, or approximately equal to half the resonant frequency. The resonant frequency depends mainly on the inductance of the secondary winding 8 of the transformer 8 and the capacitance of the discharge cell 2. The capacitance of the discharge cell 2 in turn depends on e.g. the material and thickness of the insulating material between the electrodes, which, during operation of the electric discharge device, includes the fluid to be restructured.

(16) In order for the electric discharge device 1 to be efficiently used with different fluids, including both gases and liquids, the drive circuit 3 may comprise a frequency modulator 12 for adapting the driving frequency of the DC voltage applied to the primary winding 7 to the fluid to be restructured. As understood from above, this involves adaption of the driving frequency, f.sub.0, to the resonant frequency of the cell circuit, which depends on the type of fluid to be restructured by the discharge cell. The frequency modulator 12 may be configured to automatically determine a driving frequency based on information related to the fluid to be restructured, which information may be manually input to the electric discharge device 1 via a user interface (not shown) of the device, or obtained and communicated to the frequency modulator by one or more fluid analysers (not shown). Alternatively, the frequency modulator 12 may be a manual actuator allowing the user to manually set the driving frequency of the electric discharge device 1. Typically, the driving frequency, f.sub.0, is within the range of 0.1 kHz-50 kHz, depending on the characteristic of the discharge cell 2 and the fluid to be restructured. In some embodiments, the electric discharge device 1 may be adapted for driving frequencies in the range of 100-1000 Hz. In other embodiments the electric discharge device 1 may be adapted for high-frequency operation using a driving frequency of 1000 Hz, or more. The electrode potential, i.e. the potential between the first and the second electrodes of the discharge cell 2, is typically within the range of 5 kV-25 kV, and preferably within the range of 7-12 kV.

(17) FIG. 2 illustrates schematically a discharge cell 2 of the electric discharge device 1 of the present disclosure.

(18) The discharge cell 2 comprises a first electrode 13A and a second electrode 13B arranged on a distance from each other and connected to the transformer 5 of the drive circuit 3 in order for a potential difference to be generated between the electrodes. Two spaced-apart dielectric layers 14A and 14B are interposed between the first and the second electrodes. The dielectric layers 14A and 14B define a flow channel 15 through the discharge cell 2 for the fluid to be restructured. The dielectric layers separate the fluid in the flow channel 15 from the first and second electrodes 13A and 13B. The first dielectric layer 14A is arranged against or proximate to the first electrode 13A, and the second dielectric layer 14B is arranged against or proximate to the second electrode 13B. Besides separating the fluid to be restructured from the electrodes 13A, 13B, the dielectric layers 14A and 14B serve to diffuse electric discharge from one or both of the first and second electrodes 13A, 13B over the area of the discharge cell so as to create substantially uniform corona discharge within the flow channel 15. The electrodes 13A and 13B may be any type of electrodes known in the art for generation of corona discharge and be realized in different sizes, shapes and materials. The dielectric layers 14A and 14B may be formed by any known insulating material, such as glass, ceramic, quartz or mica.

(19) Also shown in FIG. 2 are optional catalyser layers 16A and 16B. In some applications, in particular when the electric discharge device 1 is used for molecular restructuring of liquids, a metallic catalyser layer comprising cadmium and/or nickel, arranged between one or both electrodes and a neighbouring dielectric layer, has been found to improve the efficiency of the electric discharge device 1 in terms of its cracking ability. In particular, a cadmium-containing catalyser layer has been found advantageous in applications where the electric discharge device 1 is used for generation or refinement of fuel. Such an optional catalyser layer 16A, 16B may be arranged between one or both of the first electrode 13A and the first dielectric layer 14A, and the second electrode 13B and the second dielectric layer 14B.

(20) As illustrated in FIG. 1, the discharge cell 2 of the electric discharge device 1 may be shaped as a tube, and preferably a cylindrical tube. An exemplary embodiment of a cylindrical discharge cell will now be described with reference to FIGS. 3A-E.

(21) FIGS. 3A and 3B illustrate a side view and a top view, respectively, of a cylindrical discharge cell 2. FIGS. 3C-3E are cross-sectional views of the discharge cell 2 taken along the lines 3C-3C, 3D-3D and 3E-3E, respectively, in FIGS. 3A and 3B.

(22) As best seen in FIGS. 3C and 3D, the discharge cell 2 comprises a single-piece, double-walled dielectric cylinder 17 having a cylindrical inner wall 17A and a cylindrical outer wall 17B, corresponding to the respective first and second dielectric layers 14A and 14B in FIG. 2. The inner and outer walls 17A, 17B are formed as inner and outer concentrically arranged dielectric cylinders which come together at both ends to form a hollow cylindrical shell that is closed in both ends by side walls 17C. The double-walled dielectric cylinder 17 is moulded in one piece from a dielectric material. Preferably, the dielectric material is a heat-resistant and non-brittle glass, such as borosilicate glass.

(23) The annular space between the inner wall 17A and the outer wall 17B of the double-walled dielectric cylinder forms a flow channel 15 for the fluid to be reconstructed. The double-walled cylinder 17 comprises at least one inlet 19 for feeding fluid to be restructured into the annular flow channel, and at least one outlet 21 for discharge of fluid that has been restructured. In this exemplary embodiment, the inlet 19 and outlet 21 are formed on the envelope surface of the double-walled cylinder 17, i.e. in the outer cylindrical wall 17B thereof, in opposite ends of the double-walled dielectric cylinder 17. The inlet 19 and outlet 21 are provided with a respective connection nipple protruding from the outer cylindrical wall 17B. The inlet nipple is configured for connection to a hose or a matching connector of a device for feeding fluid to be molecularly restructured into the discharge cell 2, and the outlet nipple is configured for connection to a hose or a matching connector of a device for conveying cracked fluid away from the discharge cell 2. In FIG. 3C, flow through the discharge cell 2 of the fluid to be restructured has been indicated by black arrows.

(24) As best seen in FIGS. 3C and 3E, an inner electrode 23A, corresponding to the first electrode 13A in FIG. 2, is arranged around the inside of the double-walled cylinder 17, inside of the inner wall 17A, and an outer electrode 23B, corresponding to the second electrode 13B in FIG. 2, is arranged around the outside of the double-walled cylinder 17, outside of the outer wall 17B. As indicated in FIG. 1, both the inner electrode 23A and the outer electrode 23B are coupled to the transformer 5 for generating a high voltage between the electrodes.

(25) In this exemplary embodiment, both the inner electrode 23A and the outer electrode 23B are constituted by metal foils, such as stainless steel foils. The electrodes are cylindrically shaped and concentrically arranged with respect to each other and the double-walled dielectric cylinder 17. Between the inlet 19 and the outlet 21, the inner electrode 23A substantially covers the inner surface of the inner wall 17A, and the outer electrode 23B substantially covers the outer surface of the outer wall 17B. In accordance with the discharge cell illustrated in FIG. 2, the discharge cell 2 further comprises a cadmium and/or nickel containing catalyser layer 16. In this embodiment, the catalyser layer 16 is arranged between the outer electrode 23B and the outer wall 17B of the double-walled dielectric tube 17.

(26) A through channel 25 extending in the axial direction of the double-walled dielectric cylinder 17, from one end to the other, is provided inside of the inner wall 17A. The configuration of the double-walled dielectric cylinder 17 thus allows for a cooling medium, such as air, to pass through the interior of the discharge cell 2, along the centre axis thereof, as illustrated by white arrows in FIG. 3C. In order for the cooling medium to flow freely through the through channel 25, the discharge cell 2 is preferably mounted in the electric discharge device 2 without the use of end-caps or any other component covering any of the opposed openings of the through channel 25.

(27) For example, the discharge cell 2 may be mounted in a stand (not shown) that securely attaches the discharge cell 2 to a base plate, a wall plate or another fixed component of the electric discharge device 1. With reference to FIG. 3A, such a stand could, for example, comprise two support elements that, in one end, are securely fixed to a base plate or the like, and, in the other end, are securely fixed to the double-walled dielectric cylinder 17, at or close to a respective end thereof. For example, the tube-facing ends of the support elements could be attached by means of adhesive to the outer surface of the outer wall 17B not covered by the outer electrode 23B. In this exemplary scenario, the double-walled dielectric cylinder 17 could thus be attached to a stand for fixating the discharge cell 2 in the electric discharge device 1 by the outer (envelope) surface of the double-wall dielectric tube 17 being adhered to support elements of the stand, near the respective ends of the double-walled cylinder 17.

(28) The electric discharge device 1 may be configured for either active or passive cooling. With reference again made to FIG. 1, the electric discharge device 1 may for example comprise a cooling device 27 for directing a flow of cooling medium towards the discharge cell 2. Preferably, the cooling device 27 is configured to direct the flow of cooling medium towards an end of the discharge cell 2, such that the cooling medium flows into the through channel 25 to cool the interior of the discharge cell 2 and, in particular, the inner electrode 23A. The cooling device 27 is preferably configured both to generate the flow of cooling medium and to direct the flow towards an end of the discharge cell 2. In the embodiment illustrated in FIG. 1, the cooling device 27 is a fan or blower for generating a flow of air, acting as cooling medium.

(29) The dimensions of the double-walled dielectric tube 17 and the other components of the discharge cell 2 may differ substantially depending on the intended use of the electric discharge device 1.

(30) In an exemplary embodiment where the electric discharge device 1 is particularly intended for ozone generation from an oxygen-containing feed gas, but may be used for molecular restructuring of any fluid, including liquids, the electric discharge device 1 is devised and configured in accordance with the below specification. In this embodiment, the discharge cell 2 is configured in accordance with the discharge cell illustrated in FIGS. 3A-3E, except for the illustrated discharge cell being provided with a catalyser layer 16 and not being drawn to scale.

(31) Double-Walled Dielectric Tube

(32) Dielectric material: Glass (borosilicate)

(33) Length: 153 mm

(34) Outer tube diameter (Ø.sub.outer): 43 mm

(35) Inner tube diameter (Ø.sub.inner): 34 mm

(36) Inner wall thickness: 3 mm

(37) Outer wall thickness: 3 mm

(38) Flow channel width: 3 mm

(39) Inlet/outlet inner diameter: 3 mm

(40) Inlet/outlet outer diameter: 9 mm

(41) Other Specifications

(42) Inner electrode: Cylindrical stainless steel foil

(43) Outer electrode: Cylindrical stainless steel foil

(44) Driving frequency (f.sub.0): ˜2.4 kHZ

(45) Electrode potential: ˜8.5 kV

(46) Use of catalyser layer: No

(47) Catalyser material: —

(48) Catalyser layer thickness: —

(49) Cooling: Active or passive air cooling

(50) Power supply: ˜230V, 50 or 60 Hz

(51) As mentioned above, an electric discharge device that is devised and configured in accordance with the above specification may be used for molecular restructuring of both gases and liquids. However, to further optimize the electric discharge device for use with liquids, the driving frequency, f.sub.0, typically needs to be adjusted due to the change in resonant frequency of the cell circuit, occasioned by the relatively high viscosity and different molecular composition of the liquid compared to the oxygen-containing gas used for ozone production. Also, when otherwise configured in accordance with the above specification, the discharge cell 2 is advantageously provided with a cadmium and/or nickel-containing catalyser layer interposed between the outer electrode 23B and the outer wall 17B of the dielectric tube 17, and/or the inner electrode 23A and the inner wall 17A of the dielectric tube 17, in order to optimize the electric discharge device 1 for use with liquids.

(52) FIG. 4A illustrates a discharge cell 2 according to another embodiment of the present disclosure. The discharge cell 2 is identical with the discharge cell of FIGS. 3A-3E except that the discharge cell comprises electrode-covering dielectric layers 27A, 27B that cover the inner and outer electrodes 23A, 23B and prevent them from getting into contact with ambient air and the cooling medium passing through the through channel 25 of the double-walled dielectric tube 17. This has the effect of preventing moisture and dust in the ambient air and/or the cooling medium to corrode or otherwise adversely affect the function of the electrodes.

(53) The electrode-covering layers 27A, 27B may be made of any dielectric material but is preferably made of the same dielectric material as the double-walled dielectric cylinder 17. Consequently, in one exemplary embodiment, both the inner and outer walls 17A, 17B of the double-walled dielectric cylinder 17 and the electrode-covering layers 27A, 27B are made of glass, such as borosilicate glass. Preferably, the electrode-covering layers 27A, 27B forms an integral part of the double-walled dielectric cylinder 17 and serves to retain the inner and outer electrodes 23A, 23B against the inner surface of the inner wall 17A and the outer surface of the outer wall 17B, respectively. In other words, the inner electrode 23A is sealed within an inner wall of the dielectric tube 17, formed by the inner wall 17A and the inner electrode-covering layer 27A, and the outer electrode 23B is sealed within an outer wall of the dielectric tube 17, formed by the outer wall 17B and the outer electrode-covering layer 27B. In this way, the entire discharge cell 2, including the dielectric layers, electrodes and any optional catalyser layer, may be formed as a single, integral part.

(54) An exemplary method for manufacturing the discharge cell 2 may comprise the steps of moulding the double-walled dielectric cylinder 17 in one-piece, positioning a cylindrical inner electrode 23A against or proximate to the inner surface of the inner wall 17A, along a portion of the axial extension of the dielectric tube 17, positioning a cylindrical outer electrode 23B against or proximate to the outer surface of the outer wall 17B of the dielectric tube 17, along an axial extension of the dielectric tube 17 overlapping the axial extension of the inner electrode 23A, and applying electrode-covering dielectric layers 27A, 27B onto the surfaces of the inner and outer electrodes 23A, 23B not facing the double-walled dielectric tube 17. The electrode-covering layers 27A, 27B may have adhesive properties and be applied such that they adhere to the inner surface of the inner wall 17A and the outer surface of the outer wall 17B in the respective axial ends of the electrodes 23A, 23B, thereby retaining the electrodes in fixed spatial relationship with the dielectric tube 17 while preventing the electrodes from getting into physical contact with the cooling medium and/or ambient air. Cables or cable connectors may be connected to the electrodes prior to application of the electrode-covering dielectric 27A, 27B to render possible subsequent connection of the inner and outer electrodes 23A, 23B to the transformer 5 of the electric discharge device 1, via the first and second cables 10, 11 illustrated in FIG. 1.

(55) As best shown in FIG. 4B, illustrating a cross-sectional view of the discharge cell 2 in FIG. 4A, taken along the line 4B-4B, the electrode-covering layers 27A, 27B constitute an innermost dielectric cylinder and an outermost dielectric cylinder of the discharge cell 2. Consequently, in this embodiment, the dielectric cylinder 17 actually constitutes a four-walled dielectric cylinder comprising four concentrically arranged cylindrical walls of different diameters, at least along the axial extensions of the electrodes 23A, 23B. In the order of increasing diameter, the inner electrode 23A is arranged between a first and a second dielectric cylinder, formed by the inner electrode-covering dielectric layer 27A and the inner wall 17A of the double-walled dielectric cylinder 17, the annular flow channel 15 for the fluid to be reconstructed is arranged between the second and third dielectric cylinder, formed by the respective inner and outer walls 17A and 17B of the double-walled dielectric cylinder 17, and the outer electrode 23B is arranged between the third and the fourth dielectric cylinder, formed by the outer wall 17B of the double-walled dielectric cylinder 17 and the outer electrode-covering dielectric layer 27B.

(56) FIG. 5 illustrates a discharge cell 2 according to yet another embodiment of the present disclosure. In this embodiment, the inlet and outlet for the feed fluid are not located on the envelope surface of the double-walled dielectric tube 17. Instead, the discharge cell 2 comprises at least one inlet 19′ for the feed fluid arranged on a side wall 17C of the double-walled dielectric tube, i.e. an inlet 19′ that is formed in the wall part that is substantially perpendicular to the longitudinal extension of the double-walled dielectric tube 17 and connects the inner wall 17A with the outer wall 17B. The at least one inlet 19′ may comprise a plurality of apertures formed in the side wall 17C. Likewise, at least one outlet 21′ of the flow channel 15 is constituted by a plurality of apertures formed in the side wall 17C of the opposite end of the double-walled dielectric tube 17. Each inlet 19′ may be provided with a connector 29 for connection to a hose or a matching connector 30 of a device 31 for feeding fluid to be restructured into the discharge cell 2. Likewise, each outlet 21′ may be provided with a connector 32 for connection to a hose or a matching connector of a device (not shown) for conveying the cracked fluid away from the discharge cell 2. The connectors 29, 32 may be provided in form of connection nipples protruding from the end walls 17C of the double-walled tube 17 and surrounding the apertures constituting inlets and outlets of the discharge cell 2.

(57) With simultaneous reference to previous drawings, methods for molecular restructuring of fluids according to various embodiments of the present disclosure will now be described with reference to FIGS. 6-9. The methods are performed using the electric discharge device 1 as illustrated in FIG. 1, equipped with a discharge cell 2 as illustrated in any of the FIGS. 2-5, and preferably a discharge cell 2 as illustrated in any of the FIGS. 3-5.

(58) FIG. 6 illustrates a general method for molecular restructuring of a fluid.

(59) In a first step, S61, a voltage is applied between the electrodes of the discharge cell to generate corona discharge in the flow channel within the discharge cell, as described above with reference to FIG. 1. The flow channel is formed by two spaced-apart dielectric layers arranged between the electrodes, which dielectric layers prevent the fluid from getting into physical contact with the electrodes of the discharge cell.

(60) In a second step, S62, a feed fluid to be molecularly restructured is fed into the flow channel and subjected to the corona discharge. As a result, the feed fluid is cracked into a cracked fluid having another molecular composition than the feed fluid. That the feed fluid is cracked means that at least some of the molecules of the feed fluid are cracked into lighter molecules which may or may not combine into other molecules, thereby producing a cracked fluid that comprises molecules not found in the feed fluid. The cracked fluid is then discharged from the discharge cell, typically for subsequent use in another physical or chemical process, such as a process for purification of wastewater or combustion of the cracked fluid for propulsion of a vehicle.

(61) The feed fluid may, for example, be an oxygen-containing gas that is fed through the discharge cell to produce ozone. The ozone may then be used in a wide variety of applications, for example for purification of contaminated water, including both drinking water and wastewater. In other embodiments, the feed fluid is a liquid that is cracked by the electric discharge device for the purpose of purifying, refining and/or activating the liquid prior to subsequent use of the cracked liquid in other physical or chemical processes. In other embodiments, the feed fluid may be a fuel that is refined into a more reactive fuel by the cracking process prior to combustion of the fuel in a combustion engine. The method may also be employed to produce biofuel from vegetable oils, such as jatropha oil, palm oil or rape seed oil.

(62) FIGS. 7A and 7B illustrate a system 33 and method for wastewater purification according to an exemplary embodiment of the present disclosure. The method is based on the known principle of generating ozone by conducting oxygen-containing gas, such as air or oxygen, through a discharge cell of an electric discharge device, and adding the ozone to a wastewater reservoir 34 for purification of wastewater. The discharge cell is the discharge cell 2 described above with reference to any of FIGS. 2-5, forming part of an electric discharge device 1 as described with reference to FIG. 1. For the sake of simplicity, only the discharge cell 2 of the electric discharge device 1 is shown in the drawing.

(63) In the proposed method, hydrogen peroxide is added to the flow of oxygen-containing gas (step S71), upstream of the discharge cell 2. For example, the hydrogen peroxide may be injected into a feed conduit 35 for the oxygen-containing gas, which feed conduit 35 is connected to the inlet 19 of the discharge cell 2. The mixture of oxygen-containing gas and hydrogen peroxide is fed into the discharge cell 2 and subjected to the corona discharge (step S72), whereby a reactive mixture comprising ozone and hydroxyl radicals is produced. The reactive mixture is then fed to the wastewater reservoir 34 via a reactive mixture feed line 36 connected to the outlet 21 of the discharge cell 2, and added to the wastewater (step S73).

(64) As well-known in the art, the hydroxyl radical that is produced from hydrogen peroxide by the discharge cell 2 is highly reactive and reacts with many pollutants and, in particular, many volatile organic compounds. The pollutants are typically decomposed by the hydroxyl radical by removal of a hydrogen atom from the pollutant, forming water and an alkyl radical. The combination of the hydroxyl radicals and the ozone produced by the discharge cell 2 from the oxygen-containing feed has a powerful detergent effect on the wastewater. The proposed method in which a mixture of gas (oxygen-containing gas) and liquid (hydrogen peroxide) is fed through the discharge cell 2 is rendered possible by the design of the discharge cell 2 according to the present disclosure, and, in particular, by the double-wall structure of the dielectric tube 17 that prevents moisture in the feed fluid from reacting with the electrodes of the discharge cell.

(65) FIGS. 8A and 8B illustrate a system 37 and method for production and/or refinement of biofuel according to an exemplary embodiment of the present disclosure. More specifically, FIGS. 8A and 8B illustrate a system and method for production of biodiesel from jatropha oil, although the method is applicable also to other vegetable oils, such as palm oil and rape seed oil. The biodiesel that is produced through the method is particularly intended to be used for vehicles, i.e. for combustion in a biodiesel-compatible combustion engine of a vehicle.

(66) As illustrated in FIG. 8A, jatropha oil is fed into the discharge cell 2 via a feed line connected to the inlet 19 of the discharge device. The discharge cell is the discharge cell 2 described above with reference to any of FIGS. 2-5, forming part of an electric discharge device 1 as described with reference to FIG. 1. For the sake of simplicity, only the discharge cell 2 of the electric discharge device 1 is shown in the drawing.

(67) In the discharge cell 2, the jatropha oil passes through the flow channel 15 of the discharge cell 2 wherein the jatropha oil is subjected to corona discharge that cracks the jatropha oil into a resulting substance (“resultant”) having a different molecular composition than jatropha oil. The cracking ability and, thus, the ability of the discharge cell 2 to turn the jatropha oil into useful biodiesel, depends on the intensity of the corona discharge within the discharge cell and the time during which the oil is subjected to the corona discharge. Theoretically, should the discharge cell be long enough, the fluid flow be low enough, and the intensity of the corona discharge be high enough, a single passage of jatropha oil through the discharge cell could be enough to turn the jatropha oil into biodiesel. In practice, however, it has been found difficult to obtain useful biodiesel from a single passage of jatropha oil through a single discharge cell 2. Furthermore, it has been found that continuously subjecting jatropha oil (and most other fluids) to corona discharge during too long periods of time may bring about negative effects, for example generation of undesired by-products. Therefore, the jatropha oil is preferably fed through the discharge cell 2 multiple times, or fed through a plurality of discharge cells connected in series. This will gradually turn the jatropha oil into useful biodiesel while allowing the fluid to come to rest between each passage through the corona discharge field. When the substance resulting from the multiple passages through the discharge cell(s) exhibits certain desired characteristics, or after having passed through a discharge cell 2 a predetermined number of times, the process is interrupted and biodiesel is extracted from the substance.

(68) The above process for production of biofuel from vegetable oils, exemplified by a process for production of biodiesel from jatropha oil, is summarized in FIG. 8B.

(69) In a first step S81, jatropha oil is fed through the discharge cell 2 to produce a resulting substance. If biodiesel is not obtainable from the resulting substance, the method proceeds to step S82, whereby the resulting substance is fed through the discharge cell again, or fed through a further discharge cell (not shown) connected in series with the illustrated discharge cell. This process is repeated until biodiesel is obtainable from the resulting substance having passed through the discharge cell(s), whereby the method proceeds to step S83 in which biodiesel is obtained from the resulting substance.

(70) Typically, the jatropha oil should be fed through a discharge cell at least three times, more preferably in the range of four to six times, and most preferably five times. For optimal cracking of the jatropha oil, the temperature of the fluid should be maintained in the range of 30 to 45 degrees Celsius during the process, more preferably in the range of 35 to 40 degrees Celsius, and most preferably at approximately 38 degrees Celsius. Therefore, if required, the method may further comprise a step of heating the fluid prior to feeding it through the discharge cell.

(71) Biodiesel is typically extracted from the resulting substance through a separation process in which the resulting substance is separated into a first substance which mainly comprises glycerine, and a second substance constituting a liquid which, directly or after further refinement, may be used as biodiesel.

(72) The separation process may comprise a sedimentation process in which glycerine is suspended to settle out of the resulting substance. For example, the substance resulting from the one or more passages through the discharge cell may be collected in a reservoir 38 where it is stored for a time period allowing glycerine to settle as sediment on the bottom of the reservoir. The fluid found on top of the glycerine after the sedimentation process is biodiesel that may be used for combustion in combustion engines, or for other purposes. A passive sedimentation process caused by gravity may take approximately 3-5 days.

(73) FIGS. 9A and 9B illustrate a system and method for refinement of fuel in a vehicle 39, prior to combustion of the fuel in a combustion engine 41 of the vehicle. The combustion engine is typically an internal combustion engine (ICE) and the fuel may be either a fossil fuel, such as conventional diesel, or a renewable fuel, such as biodiesel. The vehicle 39 may be any type of vehicle, e.g., a car, a bus, a truck or a ship.

(74) The vehicle 39 comprises a fuel system, generally denoted by reference numeral 40, comprising a fuel supply tank 43 and a fuel supply line for feeding fuel from the fuel supply tank to a combustion engine 41. The vehicle further comprises an electric discharge device 1, as described above with reference to FIG. 1, including a discharge cell 2 as described in more detail with reference to any of FIGS. 2-5. For the sake of simplicity, only the discharge cell 2 of the electric discharge device 1 is shown in the drawing.

(75) The discharge cell 2 is mounted upstream of the combustion engine 41 and forms an integral part of the fuel supply line. The fuel is fed from the fuel supply tank 43 to the discharge cell 2 via a first conduit 45A of the fuel supply line, connected to the inlet 19 of the discharge cell 2. In the discharge cell 2, the fuel is fed through the flow channel 15 in which it is subjected to corona discharge that is adapted to crack the fuel molecules to produce a refined fuel having a different and more combustion-efficient molecular composition. It should be noted that the discharge cell 2 is not mounted around a fuel supply conduit through which the fuel passes but constitutes an integrated part of the fuel supply line in the meaning of the dielectric layers of the discharge cell constituting the walls of the fuel supply line. Also, it should be emphasized that the discharge cell 2 is configured to change the molecular composition of the fuel by subjecting the fuel to a corona discharge having an intensity that effectively cracks the molecules of the fuel. This is in contrast to prior art solutions in which the fuel is subjected to an electromagnetic field that only serves to electrically charge the fuel for improved combustion thereof in the combustion engine.

(76) After passage through the flow channel 15 of the discharge cell, the refined fuel is fed to the combustion engine via a second conduit 45B of the fuel supply line, connected to the outlet 21 of the discharge cell. In the combustion engine 41, the cracked fuel is mixed with an oxidizer (usually air) for combustion of the fuel-oxygen mixture in a combustion chamber of the engine 41. Exhaust gas resulting from the combustion is discharged into atmosphere through an exhaust line 47, such as an exhaust pipe of the vehicle 39. Besides increased combustion efficiency, the cracking of the fuel prior to combustion tends to reduce noxious gas in the exhaust gas.

(77) In some embodiments, the fuel system may further comprise a fuel return line 46 for returning some of the cracked fuel that has passed through the discharge cell 2 to a volume of the fuel system 40 that is located upstream of the discharge cell 2. This is advantageous in that the fuel can be made to pass through the discharge cell 2 multiple times prior to combustion thereof in the combustion engine 41, thereby further increasing the combustion efficiency and reducing noxious gas in the exhaust gas. In the illustrated embodiment, the fuel return line 46 is configured to return some of the fuel that has passed through the discharge cell 2 to the fuel supply tank 43. This has the further effect of allowing the cracked fuel to come to rest before again being subjected to the corona discharge field in the discharge cell 2.

(78) It should be noted that many components typically forming part of the fuel system in FIG. 9A have been left out of the drawing in order not to obscure the drawing with unnecessary detail. For example, the fuel system may include one or more fuel pumps, injection pumps, fuel filters, pressure gauges, injection nozzle, or any other component typically found in a conventional vehicle fuel system.

(79) The method for refinement of fuel in a vehicle, prior to combustion of the fuel in a combustion engine of the vehicle, is summarized in FIG. 9B.

(80) In a first step, S91, fuel is fed from the fuel supply tank 43 to the discharge device 2. In a second step, S92, the fuel is subjected to corona discharge within the discharge cell 2 and is cracked into a refined and more combustion-efficient fuel. In a third step S93, the refined fuel is fed to the combustion engine 43 for combustion within a combustion chamber. As discussed above, the method may further comprise a step of feeding some of the refined fuel through the discharge cell at least a second time, prior to feeding the refined fuel to the combustion engine, in order to further increase combustion efficiency.

(81) FIGS. 10A and 10B illustrate a system 49 and method for treatment of industrial process water, i.e. industrial wastewater that is produced as a by-product of industrial or commercial activities.

(82) The system 49 in FIG. 10A comprises a reservoir 51 for collection of industrial process water comprising chemical waste components from an industrial process taking place at an industrial site, for example in a factory 53. The system further comprises an electric discharge device 1, as described above with reference to FIG. 1, including a discharge cell 2 as described in more detail with reference to any of FIGS. 2-5. For the sake of simplicity, only the discharge cell 2 of the electric discharge device 1 is shown in the drawing. A feed line 55A is connected between the reservoir 51 and the inlet 19 of the discharge cell 2 for feeding the collected industrial process water into the discharge cell 2. The industrial process water then passes through the flow channel 15 of the discharge cell 2, wherein it is subjected to the corona discharge field between the electrodes of the discharge cell, which corona discharge field effectively cracks at least some of the chemical waste components in the industrial process water into constituents that are less hazardous or harmful to the environment. After passage through the discharge cell 2, the so treated industrial process water is discharged from the discharge cell 2 via a line 55B for treated industrial process water, connected to the outlet 21 of the discharge cell 2. In some embodiments, the line 55B for treated industrial process water may be connected to a subsystem 57 for subsequent treatment of the cracked chemical waste components in the industrial process water. Although not shown in the drawing, the system 49 may also comprise one or several subsystems for pre-treatment of the industrial process water, arranged upstream of the discharge cell 2. The system 49 may further comprise a return line 59 for returning some or all of the treated industrial process water that has passed through the discharge cell 2 to the reservoir 51, or any other volume that is located upstream of the discharge cell 2. This is advantageous in situations in which the industrial process water should be made to pass through the discharge cell 2 multiple times for optimal treatment thereof.

(83) Passing the industrial process water through the discharge cell 2 has the effect of producing oxidizing agents in the industrial process water. It also has the effect of cracking toxic chemical components into lighter, more reactive and more disintegrable or decomposable components. The cracked chemical components may be disintegrated by the oxidizing agents thus formed in the industrial process water itself, or they may be disintegrated in subsequent and conventional processes for treatment of industrial process water, performed on the industrial process water by the subsystem 57, after having passed through the discharge cell 2. It has been found that the cracking by the discharge cell 2 of the chemical components of the industrial process water facilitates disintegration of the chemical components in the subsequent processes. For example, it has been shown that removal of heavy metals in the industrial process water is facilitated by first having the industrial process water pass through the discharge cell 2. Conventional techniques that may be used for subsequent removal of heavy metals in the industrial process water may include, for example, chemical precipitation, flotation, adsorption, ion exchange, and electrochemical deposition. It should thus be understood that the system 49 may comprise a subsystem 57 for subsequent treatment of industrial process water having passed through the discharge cell 2, which subsystem 57 may comprise means for removal of heavy metals, including but not limited to known means for chemical precipitation, flotation, adsorption, ion exchange, and electrochemical deposition. Preferably, the subsystem 57 comprises means for precipitation of heavy metals.

(84) The method for treatment of industrial process water is summarized in FIG. 10B.

(85) In a first step, S101, industrial process water is collected. In a second step, S102, the industrial process water is fed through the discharge cell 2 in which it is subjected to corona discharge that serves to crack chemical components in the industrial process water into more reactive and disintegrable chemical components. As clear from above, the method may further comprise an optional and subsequent step S103 of removal of heavy metals in the industrial process water having passed through the discharge cell 2, for example through precipitation, such as chemical precipitation of heavy metals.

(86) All of the above mentioned methods involving molecular restructuring of fluids, described with reference to FIGS. 6-10, may be performed using any discharge cell having two spaced-apart dielectric layers arranged between the electrodes, which dielectric layers prevent the fluid from getting into physical contact with the electrodes of the discharge cell. Preferably, however, the methods are performed using a discharge cell having a double-walled dielectric tube 17, as illustrated in FIGS. 3-5, whereby the fluid, may it be liquid or gas, is fed through a flow channel 15 that is delimited by the inner 17A and outer 17B walls of the double-walled dielectric tube.