Rotational Electro-Oxidation Reactor
20210017050 ยท 2021-01-21
Assignee
Inventors
Cpc classification
C02F1/46104
CHEMISTRY; METALLURGY
C02F2001/46138
CHEMISTRY; METALLURGY
International classification
Abstract
An electrochemical oxidation reactor includes rotatable electrodes inside a reactor vessel. The electrodes are mounted to support plates, which in turn are mounted on shafts. The plates are attached to each other in a spaced relationship so that a gap is formed therebetween. The plates are each electrically insulated from each other. The electrodes are mounted to the inside surfaces of these plates, inside the gap. The gap is sized to receive liquid to be treated so that liquid located within the gap will react with the electrodes. An electrical charge is applied to each shaft so that a dielectric is formed across the gap within the fluid located in the gap. According to a first embodiment, an electrochemical reactor includes containing two spaced electrode support plates. According to another embodiment, an electrochemical reactor includes several spaced electrode support plates.
Claims
1-23. (canceled)
24. An electrochemical oxidation reactor for treating a liquid, comprising: a hollow body having a cylindrical cavity with an inlet and an outlet, the liquid being selectively movable between the inlet and the outlet, through the cavity, and the cavity defining a longitudinal axis; a rotor assembly rotatably mounted within the cavity, the rotor assembly comprising: a first electrode support plate with an inward facing surface and being secured to a first shaft; and an adjacently disposed second electrode support plate with an inward facing surface and being secured to a second shaft, the first and the second electrode support plates being secured to each other in a spaced and electrically insulative manner so that the inward facing surfaces of the first and second electrode support plates face each other and so that a first gap is formed therebetween, the first and the second shafts being rotatable about the longitudinal axis, the inlet being positioned to direct the liquid into the first gap adjacent the longitudinal axis; a first electrode being secured to the first electrode support plate on the inward facing surface of the first electrode support plate; a second electrode being secured to the second electrode support plate on the inward facing surface of the second electrode support plate, the first and the second electrodes being positioned within the first gap, the first electrode including one of a positive and a negative electric charge, the second electrode including the other of the positive and the negative electric charge so that a dielectric field is created across the first gap, the dielectric field being configured to cause the first and the second electrodes to undergo an electrolytic process with the liquid located within the first gap so that oxidants are formed within the liquid, the oxidants reacting with organic material located within the liquid and thereby purifying the liquid, wherein the rotor assembly is configured to rotate within the cavity about the longitudinal axis so that the liquid within the first gap more effectively interacts with the oxidants.
25. The reactor, according of claim 24, wherein at least one of the hollow body, the rotor assembly, the first electrode, or the second electrode includes a dielectric insulation layer.
26. The reactor, according of claim 24, wherein at least one of the hollow body, the rotor assembly, the first electrode, or the second electrode includes one of Aluminum, Magnesium, Titanium, Aluminum Alloy, Magnesium Alloy, and Titanium Alloy.
27. The reactor, according to claim 24, wherein the electrodes comprise material selected from the group consisting of Boron-doped diamond, platinum, lead oxide, ruthenium oxide, and iridium oxide.
28. The reactor, according to claim 24, wherein at least one of a voltage differential between 1.5V and 24 V is applied across the first gap or an electric current between 100A/m.sup.2 and 30,000 A/m.sup.2 is applied through the first gap.
29. The reactor, according to claim 24, wherein the rotor assembly is rotated by an electric motor located outside the body and mechanically connected to either the first shaft or the second shaft.
30. The reactor, according to claim 29, wherein the motor is electrically powered and the rotor assembly is rotated at a rate between 2500 RPM and 7500 RPM.
31. The reactor, according to claim 24, wherein the rotor assembly includes a third electrode support plate located adjacent to the second electrode support plate, the third electrode support plate having an inward facing surface and being secured to the second electrode support plate in a spaced relationship so that a second gap is formed and so that liquid from the inlet is directed through the first and second gaps to be treated.
32. The reactor, according to claim 31, further comprising: a third electrode being secured to the third electrode support plate on the inward facing surface of the third electrode support plate.
33. The reactor, according to claim 24, wherein the first electrode support plate includes an opening located adjacent to the longitudinal axis, the opening allowing liquid from the inlet to flow into the first gap.
34. An electrochemical oxidation reactor for treating a liquid, the reactor comprising: a reactor vessel for containing the liquid; a rotor assembly rotatably mounted within the reactor vessel and supporting at least one positive electrode and one negative electrode, the electrodes being spaced to define a gap therebetween, and the gap being sized to receive liquid during rotation of the rotor assembly; an electric motor configured to rotate the rotor assembly; and a source of power configured to provide a voltage differential between the positive electrode and the negative electrode.
35. The reactor, according to claim 34, wherein the electrodes comprise material selected from the group consisting of Boron-doped diamond, platinum, lead oxide, ruthenium oxide, and iridium oxide.
36. The reactor, according to claim 34, wherein at least one of a voltage differential between 1.5V and 24 V is applied across the gap or an electric current between 100A/m.sup.2 and 30,000 A/m.sup.2 is applied through the electrodes and the gap.
37. The reactor, according to claim 34, wherein the electric motor is mechanically connected to the rotor assembly, and wherein the rotor assembly is rotated at a rate between 2500 RPM and 7500 RPM.
38. The reactor, according to claim 34, wherein the gap is a first gap, wherein the rotor assembly supports a second positive electrode and a second negative electrode, wherein the second electrodes are secured in a spaced relationship so that a second gap is formed, and wherein the liquid from the inlet is directed through the first and second gaps to be treated.
39. An electrochemical oxidation reactor for treating a liquid, the reactor comprising: a reactor vessel for containing the liquid; a rotor assembly rotatably mounted within the reactor vessel and including a first shaft having a first support plate and a second shaft having a second support plate, the shafts being coaxial and the first and second support plates being secured to each other in a spaced relationship so that a gap is formed therebetween, the first and second support plates being insulated from each other, and the gap being sized to receive liquid during rotation of the rotor assembly within the vessel; an electrode mounted to the first support plate within the gap; an electric motor for rotating the rotor assembly; and a source of power for electrically connecting to the shafts so that a voltage differential is created across the gap.
40. The reactor, according to claim 39, wherein the reactor vessel includes an inlet and an outlet, the inlet being located adjacent the first shaft and used to direct liquid to be treated from a location outside the reactor vessel into the gap to electrochemically interact with the electrode, and the outlet being positioned to remove treated liquid from the reactor vessel.
41. The reactor, according to claim 39, wherein the electrode comprises material selected from the group consisting of Boron-doped diamond, platinum, lead oxide, ruthenium oxide, and iridium oxide.
42. The reactor, according to claim 39, wherein the shafts are horizontally disposed and the gap is vertically disposed.
43. The reactor, according of claim 39, wherein at least one of the reactor vessel, the rotor assembly, or the electrode includes a dielectric insulation layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not to-scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity.
[0021]
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
[0028]
[0029]
[0030]
[0031]
[0032]
[0033]
DETAILED DESCRIPTION
[0034] Referring now to
[0035] All metal components described hereinafter and used in the reactor 10 can be made from metals including Aluminum, Magnesium, Titanium, or Aluminum, Magnesium or Titanium Alloys. All the component surfaces can be treated (or coated) to have high resistance against oxidation and erosion and also to provide a surface with dielectric insulation properties. If the parts are made from aluminum, the Plasma-Electric-Oxidation (PEO) process can be used to provide a thin effective dielectric insulation layer on the aluminum components. PEO changes the aluminum surface to an Al.sub.2O.sub.3 ceramic, which is a dielectric insulating surface. Processes and techniques, other than PEO, can be used.
[0036] The left and right end plates 20, 22 are secured to the body 12 so that the interface between each end plate and its respective left and right end of the body 12 forms a water-tight seal (up to a predetermined working pressure, including an acceptable safety factor). A variety of known appropriate seals can be used at these two interfaces, including gaskets and applied sealant adhesives. An O-ring 30, which can be made of rubber, positioned within a circumferential channel is preferred, as shown in
[0037] The left end plate 20 is secured to the left end 16 of the body 12 using O-ring 30 and threaded fasteners 24 so that a water-tight seal is formed at the interface of the two parts. Similarly, the right end plate 22 is secured to the right end 18 of the body 12 using O-ring 32 and threaded fasteners 24 so that a water-tight seal is formed at the interface of the two parts. O-rings can be effective at creating a tight (e.g., water tight or air tight) seal between two mating surfaces, even in assemblies where one of the surfaces moves relative to the other. O-rings are used in the present electrochemical reactor assembly at various locations where a water-tight seal is required. O-ring seal structures, including mating O-ring channels, are well known and, as such, are not described herein in detail. Such sealing details are well within the understanding of those having ordinary skill in the art.
[0038] The bore 19 of the body 12 is sized and shaped to receive a rotor assembly 34 so that the rotor assembly 34 may freely rotate within the bore 19 and about the longitudinal axis 14, as described below. In an embodiment, the distance between the rotor assembly 34 and the walls of the bore 19 are between 1 mm and 2 mm. According to a first embodiment, the rotor assembly 34 includes a left electrode support plate 36 and a right electrode support plate 38. As shown in
[0039] The electrodes 40, 44 may be made from known conventional electrode materials, such as platinum, gold, silver, magnesium, titanium, copper, lead or carbon, boron doped diamond, graphene, and other allotropes of carbon. The electrodes 40, 44 are preferably secured to the electrode support plates 36, 38 by being pressed to a tolerance-fit within the recesses formed within each of the electrode support plates 36, 38, as described above. The electrodes must be able to withstand rotation within a relatively harsh environment and cannot come loose (e.g., dislodge) during operation. Press-fit securement into the electrode support plates 36, 38 can ensure a reliable and secure attachment. Other appropriate mechanical fasteners may be used to secure the electrodes to the electrode support plates, including threaded fasteners, clamp plates, and/o an appropriate adhesive bond. The appropriate fastening method can vary depending on the type of electrode used.
[0040] The electrodes 40, 44 are preferably shaped to fit each electrode support plate 36, 38 so as to cover a maximum surface area and are secured and balanced about the longitudinal axis 14 in such a manner as to allow smooth and balanced rotation of the rotor assembly 34 during operation, as explained in greater detail below. During operation of the reactor 10, as described in greater detail below, the rotor assembly 34 can rotate between 2500 and 7500 revolutions per minutes (RPMs), depending on the size of the rotor assembly 34. Therefore, the rotor assembly 34 is expected to be balanced and can handle such rotation smoothly.
[0041] In some embodiments, the electrodes may not cover the entire electrode support plates. As such, the electrodes can be located closer to the periphery of the circular electrode support plates. Such placement can help increase the efficiency of the electrodes 40, 44 since the axial velocity of the electrode support plates 36, 38 increases with an increasing radius (i.e., the distance from the longitudinal axis). The further away from the axis of rotation (i.e., the longitudinal axis 14) of the rotor assembly 34 the electrodes 40, 44 are positioned, the faster the electrode surface can pass through the passing liquid to be treated and the more effective and efficient the reaction with the liquid can be. The plates rotate with the same RPMs. However the surface velocity relative to liquid adjacent the electrodes 40, 44 varies depending on the radial position of the liquid relative to the electrode support plates 36, 38.
[0042] As shown in
[0043] As shown in
[0044] Similarly, a right-side surface 62 of the right electrode support plate 38, can be secured to a right shaft 64. The right shaft 64 can extend through the central opening 28 of the right end plate 22 and can pass through a right shaft adaptor 66. Accordingly, a portion of the right shaft 64 can be accessible outside of the body 12 and outside of the right end plate 22.
[0045] According to embodiments of this disclosure, and as described in greater detail below, the accessible portions of the left and the right shafts 58, 64 can be used to apply electrical power to the electrodes 40, 44, via electrically conductive shafts (i.e., the left shaft 58 and the right shaft 64) and the electrically conductive electrode support plates 36, 38. Also, either or both of the shafts 58, 64 can be mechanically rotated using a motor 70, as shown in
[0046] The rotor assembly 34, including the electrodes 40, 44 and the electrode support plates 36, 38 may rotate within the bore 19 of the body 12, about the longitudinal axis 14. The rotor assembly 34 can be supported by the shafts 58, 64, which in turn, can be rotatably supported by the left and right shaft adaptors 60, 66. The left shaft adaptor 60 can include a first bore 72, centered about the longitudinal axis 14, and can be sized and shaped to receive the left shaft 58. The left shaft adaptor 60 can include an outer flange 74 with openings for receiving threaded fasteners 76. The openings of the outer flange 74 can be evenly spaced. The threaded fasteners 76 can be used to secure the left shaft adaptor 60 to the left end plate 20 about the central opening 26 and in a water-tight manner. As shown in
[0047] The mechanical shaft-seal assembly 86 is a well-known type of shaft seal that provides a reliable liquid-tight seal about the shaft 58 so that pressurized liquid, passing through the bore 19 of the body 12 to be treated, does not escape between the left shaft 58 and the left shaft adaptor 60 when the shaft 58 rotates or is stationary.
[0048] Similarly, the right shaft adaptor 66 can include a first bore 90, centered about the longitudinal axis 14, that is sized and shaped to receive the right shaft 64 and includes an external flange 92 with openings for receiving the threaded fasteners 94. The openings can be evenly spaced. The threaded fasteners 94 can be used to secure the right shaft adaptor 66 to the right end plate 22, about the central opening 28, in a water-tight manner. As shown in
[0049] The mechanical shaft-seal assembly 102 can be a well-known type of shaft seal that provides a reliable liquid-tight seal about the shaft 64 so that pressurized liquid, being treated within the bore 19 of the body 12, does not escape between the right shaft 64 and the right shaft adaptor 66 when the shaft 64 rotates or is stationary. The right shaft adaptor 66 can be almost the same as described above with respect to the left shaft adaptor 60, except that right shaft adaptor 66 can be longer (as measured along the longitudinal axis 14) and can include an inlet port 108. The inlet port 108 can be laterally disposed on right shaft adaptor 66. As shown in
[0050] All metal component surfaces of the mechanical seal can have the same surface treatment/coating, described above so as to have a high resistance against oxidation and erosion.
[0051] Referring to
[0052] Apart from the accommodation of multiple electrode plates 156, the structure, assembly, and operation of reactor 150 can be the same as the reactor 10 described above and shown in
[0053] Referring to
[0054] As compared to the reactor 10 of
[0055] Referring to the reactor 250, the rotor assembly 34 can be supported by the shafts 58, 64, which are rotatably supported by the left and right end plates 20, 22 instead of the left and right shaft adaptors 60, 66. As shown in
[0056] As shown in
[0057] The mechanical shaft-seal assembly 102 can be a well-known type of shaft seal that provides a reliable liquid-tight seal about the shaft 64 so that pressurized liquid, being treated within the bore 19 of the body 12, does not escape between the right shaft 64 and the right end plate 22 when the shaft 64 rotates or is stationary. The right end plate 22 can be almost the same as the left end plate 20, except that the right end plate 22 can include the inlet port 108. As shown in
[0058] Apart from the placement of the inlet port 108 and the absence of the left shaft adaptor 60 and the right shaft adaptor 66, the structure, assembly, and operation of reactor 250 can be the same as the reactor 10 described above and shown in
[0059]
[0060] Apart from the accommodation of multiple electrode plates 156, the structure, assembly, and operation of reactor 350 can be the same as the reactor 250 described above and shown in
[0061] In Operation:
[0062] Rotation:
[0063] In operation of the reactor 10, and referring to
[0064] The shaft speed of the motor 70 can vary depending on the dimensions and weight of the rotor assembly. Smaller diameters and lighter rotors can be expected to rotate faster than heavier rotors having larger diameters. By way of example, a rotor assembly 34 having an approximate diameter of 150 mm can be expected to operate between 5000 and 7500 RPM. As another example, a rotor assembly 34 having an approximate diameter of 450 mm can be expected to operate around 2500 RPM. The axial speed of the electrodes 40, 44 with respect to the adjacent liquid is expected to be between 40 and 50 meters per second. As stated above, the electrodes rotate about longitudinal axis 14 and this rotation allows for a high axial speed relative to the passing liquid. This higher axial speed causes the laminar sub layer of the liquid against the electrodes to narrow, sometimes considerably, which in turn can allow a higher mass transfer. While, theoretically, there may be no upper limit to the axial speed, the higher speeds can require greater energy (in powering the motor 70) and the increased G-forces can increase the engineering demands of the components.
[0065] Referring again to
[0066] Applied Voltage:
[0067] A voltage differential can be applied to the shafts 58, 64 during operation using any appropriate rotational conductor (e.g., a high-voltage mercury liquid rotational contact). The rotational conductor can be a commercially available rotational conductor. For example, commercially available rotational conductors can be obtained from Meridian Laboratory, Inc. located in Middleton, Wis. 53562, or Mercotac, Inc. located in Carlsbad, Calif. 92011. A rotary electrical connector can use mercury (or another electrical conducting liquid) to provide continuous electrical contact between a stationery component and a rotating component. The connectors can provide a low (and sometimes, an extremely low) resistance electrical connection because the electrical conduction path is a liquid metal that is molecularly bonded to the contacts. In some embodiments, brush-type slip rings of the type which include a rotating metal ring upon which a graphite or metal brush rubs and transfers an electrical current can be used to transfer power to the shafts 58, 64. However, these mechanical contact type connectors may have several deficiencies.
[0068] While brush slip rings are technically simple in operation, the physical rubbing interface can be fraught with problems including wear, high electrical resistance, oxidation, and resistance fluctuations, which causes electrical noise. The electrical noise can adversely interfere with the electrical charges on the electrodes 40, 44 and make it difficult to accurately and efficiently control the electrolytic process required with the reactor 10.
[0069] The voltage applied to the shafts 58, 64 can create a voltage differential across the gap 54 and can induce the electrolytic process causing the electrodes 40, 44 to create oxidants, such as H.sub.2O.sub.2 and O.sub.3 as well as Hydroxyl Radicals, as is understood by those skilled in the art and described in U.S. Pat. Nos. 9,028,689 and 9,061,323, the content of which are herein incorporated by reference in their entireties.
[0070] The amounts of voltage and current applied to the shafts 58, 64 can vary depending on the liquid to be treated, the solids level of the liquid, and the conductivity of the liquid. The amounts of voltage and current applied to the shafts 58, 64 can be in the range of about 100-30,000 A/m2 at a voltage of 1.5-24 V per reactor gap/channel.
[0071] According to another aspect of this disclosure, the applied voltage can be controlled in its electrical properties (e.g., voltage, amperage, etc.) while the polarity of the electrical current may be reversed in a frequency ranging from 1 HZ (1 time per second) to 5 GHz (5.0*10.sup.9 per second). The polarity reversal can allow for the production of hydroxyl radicals at the electrode plates and can result in an increased oxidation efficiency of the reactor.
[0072] Flow of Liquid:
[0073] Referring now to
[0074] Now clean, the liquid leaving the reactor 10 through the outlet port 21 can be directed through the conduit 212, then through the discharge control valve 208, and then through the conduit 214 to a clean liquid storage (not shown). In some embodiments, a return conduit (not shown) can connect the conduit 214, through a valve (not shown) to the conduit 203 so that clean water can be recycled through the reactor 10. For example, the clean water can be recycled through the reactor 10 when it be determined that the clean water discharging the outlet port 21 contains an unacceptable amount of contaminates.
[0075] The pressure of the liquid entering the reactor 10 can be controlled by the supply pump 204 and the flow of the liquid through the reactor itself can be controlled by the discharge control valve 208. According to aspects of this disclosure, the combination of the control of the feed into the reactor 10, the pressure of the liquid within the reactor 10, and the discharge from the reactor 10, the residence time of the liquid in the reactor (i.e., how long the liquid resides within the reactor 10) can be controlled. Controlling the resident time can allow the electrochemical oxidation process to have its highest efficiency in the rotational environment.
[0076] In addition to the control over the flow through the reactor vessel, controlling the rotation of the rotor assembly 34 within the bore 19 can control the axial velocity of the electrodes 40, 44 relative to the liquid located within the gap 54. The axial velocity of the electrodes 40, 44 can have a direct impact on the thickness of the laminar (viscous) sub layer. The effective axial velocity can accelerate from the feed flow rate velocity of the liquid entering the gap 54 (controlled by the supply pump 204) to a maximum axial speed velocity when the liquid reaches the periphery of the electrode support plates 36, 38. The axial speed of each point along the electrode support plates 36, 38 can increase as the location moves from the center (i.e., the longitudinal axis 14) to the periphery of each plate. With practically infinite control over electrical conditions, including applied voltage, current, frequency and type (direct or alternating voltage), as well as the speed of the electrode support plates 36, 38 and the electrodes 40, 44, an accurate control of the boundary layer thickness on the electrodes 40, 44 can be achieved. Such parameter control can allow the electrochemical oxidation process of the liquid within the gap 54 (in the rotational environment of the reactor) to perform most efficiently.
[0077] The rotational movement of the rotor assembly 34 effects the velocity of the electrodes 40, 44 and the laminar (viscous) sub layer. As such, the reactor 10 does not function as a pump and the rotation of the rotor assembly 34 within the bore 19 does not affect the flow or pressure of the liquid entering and leaving the reactor 10
[0078] The rotational axis of the rotor assembly 34 (the longitudinal axis 14) may be oriented in any direction in 3-dimensional space. In an embodiment, the rotational axis can remain horizontal so that the gap 54 is vertically disposed. In an embodiment, the contaminated liquid enters the gap 54 as close to the longitudinal axis as possible and the outlet port 21 is positioned at the top of the body 12, as shown in
[0079]
[0080] While the disclosure has been described in connection with certain embodiments, it is to be understood that the disclosure is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law. In addition, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.