Patent Publication Number: US-2021179455-A1

Title: Hydrogen peroxide water manufacturing device

Description:
FIELD 
     Embodiments of the present invention relate to a hydrogen peroxide water manufacturing device. 
     BACKGROUND 
     In the field of, for example, service water, waste water, industrial effluent, and swimming pool, ozone and UV lamps is used for processes such as oxidative decomposition, sterilization, and deodorization of organic matter in water are conventionally used. The oxidation with ozone and UV lamps can achieve hydrophilizing or low-molecular, but cannot achieve mineralization. Use of ozone or a UV lamp cannot decompose refractory organic matter such as dioxin and 1,4-dioxane. 
     To decompose the refractory organic matter in water, the advanced oxidation process has been proposed in which the refractory organic matter is oxidized and decomposed by using OH radicals having a greater oxidation power than active species according to ozone or UV lamps. 
     The advanced oxidation processes include a method of adding ozone to hydrogen peroxide water and a method of irradiating hydrogen peroxide water using a UV lamp to produce OH radicals. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Patent Application Laid-open No. 2002-531704 
     Patent Literature 2: Japanese Patent Application Laid-open No. 2010-137151 
     Patent Literature 3: Japanese Patent Application Laid-open No. 2013-108104 
     SUMMARY OF THE INVENTION 
     Problem to be Solved by the Invention 
     The method of using ozone or a UV lamp and hydrogen peroxide requires a storage facility and an injection facility for hydrogen peroxide, which is a deleterious substance. Using hydrogen peroxide requires strict control to ensure safety. 
     The present invention has been made to solve the above problem, and has an object to provide a hydrogen peroxide water manufacturing device that can manufacture hydrogen peroxide water continuously. 
     Means for Solving Problem 
     A hydrogen peroxide water manufacturing device according to an embodiment includes an ejector unit including an introduction-side diameter-increasing portion to which water to be treated is introduced, a nozzle portion connected to the introduction-side diameter-increasing portion and having an introduction opening to which a source gas containing oxygen gas is introduced from outside, on a side wall, and a discharge-side diameter-increasing portion that is connected to the nozzle portion and from which the water to be treated mixed with the source gas is discharged; and an electrolysis unit disposed downstream of the ejector unit and including electrolytic electrodes to electrolyze the discharged water to be treated mixed with the source gas and generate hydrogen peroxide by using the source gas as a source. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a block diagram illustrating a schematic configuration of a water treatment system according to embodiments. 
         FIG. 2  is an outer perspective view of a water treatment unit. 
         FIG. 3  is a schematic sectional view of the water treatment unit. 
         FIG. 4  is a diagram illustrating an example configuration of an electrolytic electrode group. 
         FIG. 5  is a diagram illustrating an example configuration of an electrolytic electrode group including a plurality of pairs of electrodes. 
         FIG. 6  is a diagram illustrating electrodes according to a second embodiment. 
         FIG. 7  is a diagram illustrating an electrode according to a third embodiment. 
         FIG. 8  is a diagram illustrating electrodes according to a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following describes embodiments with reference to the accompanying drawings. 
     [1] First Embodiment 
       FIG. 1  is a block diagram illustrating a schematic configuration of a water treatment system according to the embodiments. 
     This water treatment system  10  includes a feed-water pump  11  that supplies water LQ to be treated under pressure, an upstream existing pipe  12 , a downstream existing pipe  13 , a water treatment unit  14  disposed between the upstream existing pipe  12  and the downstream existing pipe  13  and functioning as a hydrogen peroxide water manufacturing device that continuously manufacture hydrogen peroxide water, and a gas supply device  16  that can supply a source gas containing oxygen via a gas supply pipe  15  of the water treatment unit  14 . 
     The gas supply device  16  supplies, as the source gas, oxygen-containing gas OG that contains oxygen, such as oxygen gas or air gas. 
       FIG. 2  is an outer perspective view of the water treatment unit. 
       FIG. 3  is a schematic sectional view of the water treatment unit. 
     The water treatment unit  14  includes a body  21 , a pair of flanges  23 ,  24  having a plurality of holes  22  for bolt fastening, and the gas supply pipe  15  provided close to the flange  23  in the body  21 . 
     Close to the flange  23  (close to an upper side in  FIG. 2 ) in the body  21 , disposed are an ejector unit  25  having a flow path diameter that gradually decrease and then gradually increase, and having an ozone supply opening  15 A for the gas supply pipe  15  at the portion where the flow path diameter is smallest, and an electrolysis unit  26  including electrodes (or an electrode group) described later to generate hydrogen peroxide (H 2 O 2 ). The ejector unit  25  and the electrolysis unit  26  function as the hydrogen peroxide water manufacturing device. 
     The ejector unit  25  has an introduction-side diameter-increasing portion  25 A having an inner diameter gradually increasing toward an introduction side of the water LQ to be treated, a nozzle portion  25 B, and a discharge-side diameter-increasing portion  25 C having an inner diameter gradually increasing toward a discharge side of the water LQ to be treated. 
     Here, the treatment principle of the water treatment unit  14  will be described. 
     When the feed-water pump  11  supplies the water LQ to be treated to the ejector unit  25  of the water treatment unit  14  under pressure, the speed (flow rate) of the water LQ to be treated gradually increases due to the gradually reducing flow path diameter of the ejector unit  25  from the introduction-side diameter-increasing portion  25 A toward the nozzle portion  25 B. 
     The flow rate of the water LQ to be treated is highest at the nozzle portion  25 B having the smallest flow path diameter of the ejector unit  25 , that is, highest at the portion having the ozone supply opening  15 A for the gas supply pipe  15 , and the water LQ to be treated is depressurized at the nozzle portion  25 B due to the Venturi effect. 
     The depressurized state causes the oxygen-containing gas OG supplied from the gas supply device  16  as the source gas to be introduced to the nozzle portion  25 B of the ejector unit  25 . 
     The water LQ to be treated then flows into the discharge-side diameter-increasing portion  25 C having a gradually increasing flow path diameter, of the ejector unit  25 , in which the flow rate decreases and the water pressure increases sharply, thereby producing a turbulent flow. The water LQ to be treated and the oxygen-containing gas OG are mixed strongly. 
     The water LQ to be treated and the oxygen-containing gas OG mixing substantially uniformly flows into the electrolysis unit  26 , at which hydrogen peroxide (H 2 O 2 ) is generated by the electrodes in the electrolysis unit  26  by using oxygen gas contained in the oxygen-containing gas OG as the source in accordance with formula (1) below. 
       O 2 +2H + +2 e   − →H 2 O 2   (1)
 
     As described above, when the water LQ to be treated flows into the discharge-side diameter-increasing portion  25 C having a gradually increasing flow path diameter, of the ejector unit  25 , the flow rate decreases and the pressure increases sharply. 
     This produces a turbulent flow RF as illustrated in  FIG. 3  and the water LQ to be treated and the oxygen-containing gas OG are mixed strongly. In this case, it is desired that hydrogen peroxide is still uniformly distributed in the electrolysis unit  26 . 
     In this regard, it is desired that the electrodes for use in electrolytic processes in the electrolysis unit  26  are disposed not to interrupt the produced turbulent flow as much as possible. 
     The following describes in detail the electrodes for use in electrolytic processes in the electrolysis unit  26 . 
     In the electrolysis unit  26 , as illustrated in  FIG. 3 , an electrolytic electrode group  27  is disposed immediately after the discharge-side diameter-increasing portion  25 C of the ejector unit  25  and is supplied with direct current for use in electrolytic processes from an external direct current power source  28 . 
       FIG. 4  is a diagram illustrating an example configuration of the electrolytic electrode group. 
     The electrolytic electrode group  27  in the electrolysis unit  26  includes an anode electrode  31 A and a cathode electrode  31 K having a plate-like shape. 
     As illustrated in  FIG. 4 , the anode electrode  31 A and the cathode electrode  31 K are sufficiently spaced apart and thus never interrupt the turbulent flow RF produced in the discharge-side diameter-increasing portion  25 C. 
     Although this structure does not interrupt the turbulent flow RF, it may fail to increase the reaction rate as much as expected and fail to increase the generation efficiency of hydrogen peroxide (H 2 O 2 ) because only the anode electrode  31 A generates hydrogen peroxide by using oxygen gas contained in the oxygen-containing gas OG as the source. 
     In this regard, an electrode arrangement that can increase the reaction rate is desired. 
       FIG. 5  is a diagram illustrating an example configuration of an electrolytic electrode group including a plurality of pairs of electrodes. 
     In a first embodiment, as illustrated in  FIG. 5 , anode electrodes  31 A 1  to  31 A 3  and cathode electrodes  31 K 1  to  31 K 3  are alternately arranged, and a plurality of pairs of electrodes form the electrolytic electrode group  27  of the electrolysis unit  26 . 
     In this case, an electrolytic reaction takes place between each pair of electrodes (e.g., between the anode electrode  31 A 1  and the cathode electrode  31 K 1 ). This configuration can efficiently generate hydrogen peroxide and can manufacture hydrogen peroxide water continuously. 
     According to the first embodiment described above, hydrogen peroxide water can be manufactured efficiently and continuously. 
     [2] Second Embodiment 
     In the first embodiment above, plate electrodes are described. In a second embodiment below, a more practical configuration is described that increases the manufacturing efficiency of hydrogen peroxide water by preventing the turbulent flow from being regulated. 
     The second embodiment mainly focuses on the structure of the electrodes, and the electrode arrangement is the same as that of the first embodiment. 
       FIG. 6  is a diagram illustrating electrodes according to the second embodiment. 
     The electrodes according to the second embodiment are porous plate electrodes having a plurality of randomly arranged holes with different diameters, and include an anode electrode  31 A 11  and a cathode electrode  31 K 11  as an electrode pair. 
     In this structure, the water LQ to be treated flowing between the anode electrode  31 A 11  and the cathode electrode  31 K 11  and passing therethrough becomes a random turbulent flow. This structure can increase the generation efficiency of hydrogen peroxide and thus increase the manufacturing efficiency of hydrogen peroxide water. 
     If the pairs of electrodes illustrated in  FIG. 5  are formed with the anode electrode  31 A 11  and the cathode electrode  31 K 11  according to the second embodiment, which are porous plate electrodes having a plurality of randomly arranged holes with different diameters, the manufacturing efficiency of hydrogen peroxide water increases in proportion to the increased number of electrodes as long as the flow path resistance is not significantly increased. 
     [3] Third Embodiment 
     In the first and the second embodiments above, plate electrodes are described. In a third embodiment below, an electrode having a three-dimensional shape is described. 
       FIG. 7  is a diagram illustrating an electrode according to the third embodiment. 
     In  FIG. 7 , black portions indicate pores (openings). 
     As illustrated in  FIG. 7 , an anode electrode  31 A 21  or a cathode electrode  31 K 21  according to the third embodiment has a three-dimensional porous shape (like sponge), and thus can have a sufficient surface area of the electrode and can keep the turbulent flow of the water LQ to be treated. 
     It is desired that the surface of the cathode electrode  31 K 21  is hydrophobic so as to easily take oxygen gas into the electrode surface as the source of hydrogen peroxide. In this regard, the cathode electrode  31 K 21  is made of, for example, a porous carbon electrode as the electrode core member coated with a polytetrafluoroethylene suspension, or what is called a Teflon (registered trademark) suspension (for providing hydrophobic properties), and coated with conductive carbon powder (for providing porous properties). 
     According to the third embodiment, the water LQ to be treated flowing and passing between the anode electrode  31 A 21  and the cathode electrode  31 K 21  becomes a random turbulent flow. This structure can increase the manufacturing efficiency of hydrogen peroxide water. 
     [4] Fourth Embodiment 
       FIG. 8  is a diagram illustrating electrodes according to a fourth embodiment. 
     As illustrated in  FIG. 8 , an anode electrode  31 A 31  and a cathode electrode  31 K 31  according to the fourth embodiment each include an electrode base  41  and a plurality of rod-shaped electrodes  42  projecting on the electrode base  41 , thereby having a pin holder shape. 
     The rod-shaped electrodes  42  of the anode electrode  31 A 31  and the cathode electrode  31 K 31  are randomly disposed at positions not interfering with one another when the anode electrode  31 A 31  and the cathode electrode  31 K 31  are disposed close to and opposite to each other. This structure can provide a sufficient surface area of the electrodes and can keep the turbulent flow of water LQ to be treated. 
     In the same manner as the cathode electrode  31 K 21  according to the third embodiment, it is desired that the surface of the cathode electrode  31 K 31  is hydrophobic so as to easily take oxygen gas into the electrode surface as the source of hydrogen peroxide. In this regard, the cathode electrode  31 K 31  is made of, for example, an electrode core member coated with a Teflon (registered trademark) suspension (for providing hydrophobic properties) and conductive carbon powder (for providing porous properties). 
     According to the fourth embodiment, the water LQ to be treated flowing and passing between the anode electrode  31 A 31  and the cathode electrode  31 K 31  becomes a random turbulent flow. This structure can increase the manufacturing efficiency of hydrogen peroxide water. 
     [5] Effects of Embodiments 
     According to the embodiments above, a simple and low-cost hydrogen peroxide water manufacturing device can be implemented without using hydrogen peroxide as a reagent. 
     Although several embodiments according to the present invention have been described, these embodiments are presented for illustrative purposes only and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made within the scope and spirit of the invention. The embodiments and modifications thereto are within the scope and spirit of the invention and are within the invention described in claims and equivalents thereof.