JP2013255905A - Fluid purification device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid purification device capable of preventing fatigue due to thermal expansion/contraction of a reaction tank 20 as compared with conventional ones.SOLUTION: In a fluid purification device comprising a reaction tank 20 for performing oxidative decomposition of organic matter in a cleaning object fluid, in the process of feeding a cleaning object fluid and an oxidizing agent in a longitudinal direction thereof while mixing them and a catalyst provided in the reaction tank 20 for promoting the oxidative decomposition of the organic matter, catalytic activity of the catalyst is lowered as it goes from a downstream side toward an upstream side in a fluid transport direction in the reaction tank 20 (first catalyst 26b<second catalyst 27b<third catalyst 28b).

Description

  The present invention provides a purification process in which a purification target fluid and an oxidant are mixed and fed from the front end side to the rear end side of the reaction tank in which a catalyst for promoting oxidative decomposition of organic substances is disposed. The present invention relates to a fluid purification device that purifies a purification target fluid by oxidizing and decomposing organic matter in the target fluid.

  As this type of fluid purification device, the one described in Patent Document 1 is known. In this fluid purification device, waste water as a treatment target fluid is heated to a temperature equal to or higher than the critical temperature of water (374 ° C.) in a state where it is mixed with an oxidant in a reaction tank, and the critical pressure of water (22 MPa) or higher. The wastewater is brought into a supercritical state by pressurizing at a pressure of. Then, the wastewater is purified by rapidly oxidizing and decomposing organic matter in the wastewater in the supercritical state. A catalyst that promotes oxidative decomposition of organic substances is disposed in the reaction vessel. By this catalyst, even a hardly decomposable organic substance can be oxidatively decomposed well.

  However, this fluid purification apparatus has a problem that the upstream portion in the fluid conveyance direction of the reaction tank becomes considerably hotter than the downstream portion, and metal fatigue due to expansion and contraction is likely to occur. Specifically, at the front end of the reaction tank, wastewater pumped from the outside and an oxidant (for example, air) are heated and pressurized to be mixed in a supercritical state, so that the organic matter in the wastewater is mixed. Oxidative decomposition begins rapidly. If the organic matter concentration in the wastewater is high, the oxidative decomposition reaction of organic matter occurs in the upstream region in the fluid conveyance direction of the reaction tank, so the upstream part of the reaction tank is compared to the downstream part. It becomes quite hot.

  In addition, although the fluid purification apparatus of patent document 1 heats and pressurizes waste water inside a reaction tank and makes it a supercritical state, even if it is the structure which makes waste water a subcritical state or a heating high temperature steam state. The oxidative decomposition of organic substances concentrates at the tip of the reaction tank, and the tip may be particularly hot.

  This invention is made | formed in view of the above background, The place made into the objective is providing the fluid purification apparatus which can suppress the fatigue by the thermal expansion-contraction of a reaction tank rather than before.

  In order to achieve the above object, the present invention provides an organic substance in the purification target fluid in a process in which the purification target fluid and the oxidant received inside are mixed and sent from the front end side to the rear end side. In a fluid purification apparatus comprising: a reaction tank for oxidatively decomposing and purifying the fluid to be purified; and a catalyst disposed in the reaction tank for promoting oxidative decomposition of organic matter, The catalyst capacity of the catalyst in the fluid conveyance direction is reduced from the downstream side toward the upstream side.

  In the present invention, the upstream portion of the reaction tank in the fluid conveyance direction has a lower catalytic ability of the catalyst than the downstream portion, so that the amount of organic matter that is oxidatively decomposed in the upstream portion is reduced compared to the prior art. The calorific value of the side part is reduced. On the other hand, the downstream portion of the reaction tank in the fluid conveyance direction has a higher catalytic ability of the catalyst than the upstream portion, so that the amount of organic matter that is oxidatively decomposed in the downstream portion is increased compared to the conventional case. The calorific value of the side part increases. In this way, the heat generated in the upstream and downstream portions of the reaction vessel is made uniform and the temperature rise at the upstream portion is made lower than before, thereby reducing fatigue caused by thermal expansion and contraction of the reaction vessel. Than can be suppressed.

The schematic block diagram which shows the fluid purification apparatus which concerns on embodiment. The longitudinal cross-sectional view which shows the reaction tank of the fluid purification apparatus. The disassembled perspective view which shows the same reaction tank. The graph which shows the relationship between the fluid temperature in Experiment 1, and the position in a reaction tank. The graph which shows the relationship between the fluid temperature in Experiment 2, and the position in a reaction tank.

Hereinafter, an embodiment of a fluid purification apparatus to which the present invention is applied will be described.
First, a basic configuration of the fluid purification device according to the embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating a fluid purification device according to an embodiment. The fluid purification device according to the embodiment includes a raw water tank 1, a stirrer 2, a raw water supply pump 3, a raw water inlet valve 4, an oxidant preheater 5, an oxidant pressure feed pump 6, an oxidant tank 7, an oxidant inlet valve 8, A merging section 9, a merging section thermometer 10, a heat exchanger 11, an outlet pressure gauge 12, an outlet valve 13, a gas-liquid separator 14, a reaction tank 20, a control section (not shown) are provided.

  The control unit individually supplies a power supply circuit composed of a combination of an earth leakage breaker, a magnet switch, a thermal relay, and the like to the agitator 2, the raw water supply pump 3, the preheater 5, the oxidant pressure feed pump 6, and the oxidant heat exchanger 11. It has only the corresponding amount. And the on / off of the power supply with respect to these apparatuses is controlled separately by turning on / off the magnet switch of a feed circuit with the control signal from a programmable sequencer.

  The outlet pressure gauge 12 outputs a voltage having a value corresponding to the pressure detection result. The junction thermometer 10 detects the temperature of the mixed fluid of the oxidant and waste water that merged in the junction 9 and outputs a voltage corresponding to the detection result. In addition, a first thermometer 21, a second thermometer 22, a third thermometer 23, a fourth thermometer 24, and a fifth thermometer 25, which will be described later, detect the temperature of the mixed fluid in the reaction tank 20, respectively. Outputs a voltage according to the detection result. The voltages output from these measuring devices are individually converted into digital data by an A / D converter (not shown) and then input to the programmable sequencer as sensing data. The programmable sequencer controls driving of various devices based on the sensing data.

  In the raw water tank 1, waste water containing organic substances having a relatively large molecular weight is stored in an untreated state. It comprises at least one of waste water, organic solvent waste water, paper making waste water generated in the paper manufacturing process, and toner manufacturing waste water generated in the toner manufacturing process. Papermaking wastewater and toner manufacturing wastewater may contain persistent organic substances.

  The stirrer 2 stirs the wastewater as the fluid to be purified to uniformly disperse suspended solids contained in the wastewater, thereby achieving a uniform organic substance concentration. Waste water in the raw water tank 1 is continuously pumped by a raw water supply pump 3 comprising a high pressure pump, and flows into the junction 9 through the raw water inlet valve 4 at a high pressure. The raw water inlet valve 4 plays a role of a check valve, and allows the waste water pumped from the raw water supply pump 3 to flow from the raw water supply pump 3 side to the merging portion 9 side, but in the reverse direction. Block the flow.

  The oxidant pump 6 sucks the hydrogen peroxide solution, which is the oxidant stored in the oxidant tank 7, and compresses the hydrogen peroxide solution to the same level as the inflow pressure of the wastewater, and joins it through the oxidant inlet valve 8. Send to part 9. The hydrogen peroxide solution pumped out from the oxidant pressure pump 6 enters the junction through the oxidant inlet valve 8 and the oxidant preheater 5.

  The oxidant inlet valve 8 serves as a check valve, and allows the hydrogen peroxide solution sent from the oxidant pressure feed pump 6 to flow from the oxidant pressure feed pump 6 side to the junction 9 side. On the other hand, the reverse flow is blocked. The hydrogen peroxide solution that has passed through the oxidant inlet valve 8 is preheated by the oxidant preheater 5 and then enters the junction 9.

  The mixed fluid of the hydrogen peroxide solution and the waste water that merged at the junction 9 enters the reaction tank 20. The pumping amount of the hydrogen peroxide solution driven by the oxidant pump 6 is determined based on the stoichiometric amount of oxygen necessary to completely oxidize the organic matter in the wastewater. More specifically, oxygen required for complete oxidation of organic matter based on organic matter concentration, nitrogen concentration, phosphorus concentration, etc. in wastewater, such as wastewater COD (Chemical Oxygen Demand), total nitrogen (TN), and total phosphorus (TP) The amount is calculated, and the pumping amount of the hydrogen peroxide solution is set based on the result.

  The amount of hydrogen peroxide water inflow is set by workers, but the type of organic matter contained in the wastewater is stable over time, and physical properties such as turbidity, light transmittance, electrical conductivity, specific gravity, When the correlation with the oxygen amount is relatively good, the programmable sequencer is set so that the control range is automatically corrected based on the result of detecting the physical property by a sensor or the like. It may be configured. As the oxidizing agent, hydrogen peroxide water, one of air, oxygen gas, ozone gas, or a mixture of two or more of them can be used.

  A heater 30 for heating the reaction tank 20 is disposed outside the reaction tank 20. The mixed fluid pumped into the reaction tank 20 is heated by the heater 30 and heated, and also heated by heat generated by the oxidative decomposition of the organic matter. When the wastewater contains organic matter at a high concentration, the mixed fluid may be heated to a desired temperature only by a large amount of heat generated when the large amount of organic matter is oxidatively decomposed. In this case, heating by the heater 30 is performed only when the apparatus is started up, and the power supply to the heater 30 can be turned off after the oxidative decomposition is started.

  Examples of the pressure applied to the mixed fluid in the reaction tank 20 include a range of 0.5 to 30 Mpa (desirably 5 to 30 Mpa). The pressure in the reaction tank 20 is adjusted by an outlet valve 13 described later. When the pressure in the reaction tank 20 becomes higher than the threshold value, the outlet valve 13 automatically opens the valve and discharges the mixed fluid in the reaction tank 20 to the outside, thereby maintaining the pressure in the reaction tank 20 near the threshold value. To do.

  Examples of the temperature of the mixed fluid in the reaction tank 20 include 100 to 700 ° C. (desirably 200 to 550 ° C.). The temperature is adjusted by turning the heater 30 on and off. When temperature = 374.2 ° C. or higher and pressure = 21.8 MPa or higher are adopted as temperature and pressure conditions, the critical temperature and critical pressure of water are exceeded, and the critical temperature and critical pressure of air are also exceeded. In this state, the mixed fluid becomes a supercritical fluid having an intermediate property between liquid and gas. In such a supercritical fluid, the organic matter is well dissolved in the supercritical fluid and is in good contact with air, so that the oxidative decomposition of the organic matter proceeds rapidly.

  As a condition of temperature and pressure, a relatively high pressure of temperature = 200 ° C. or higher (desirably 374.2 ° C. or higher) and pressure = 21.8 MPa (desirably 10 MPa or higher) is adopted in the reaction vessel 20. The waste water in the mixed fluid may be converted into high-temperature and high-pressure steam.

  In the reaction tank 20, the mixed fluid is brought to a high temperature and high pressure state to promote oxidative decomposition of organic matter and ammonia nitrogen in the mixed fluid. The mixed fluid obtained by oxidizing and decomposing organic matter and ammonia nitrogen is discharged from the reaction tank 20 to the treated water conveyance pipe. A heat exchanger 11 is attached to the treated water transport pipe. The heat exchanger 11 has an outer pipe that covers the outside of the treated water transport pipe, and fills the space between the appearance and the treated water transport pipe with a heat exchange fluid such as water. And heat exchange with the outer wall of a treated water conveyance pipe and a heat exchange fluid is performed. During operation of the reaction tank 20, a very high temperature processing fluid flows inside the treated water transport pipe, so heat is transferred from the treated water transport pipe to the heat exchange fluid in the heat exchanger 11, and the heat exchange fluid is heated. It is done. The transport direction of the heat exchange fluid in the heat exchanger 11 is opposite to the transport direction of the liquid in the treated water transport pipe so as to perform so-called countercurrent heat exchange. That is, the heat exchange fluid is sent from the outlet valve 13 side to the reaction tank 20 side. This is performed by a heat exchange pump that sends the heat exchange fluid in a heat medium tank (not shown) to the heat exchanger 11 while sucking it.

  The heat exchange fluid heated through the heat exchanger 11 is sent to a generator through a pipe (not shown). In the generator, power generation is performed by rotating the turbine with an air flow generated when the heat exchange fluid that has been heated to increase the pressure from a liquid to a gas state.

  An outlet thermometer, an outlet pressure gauge 12, and an outlet valve 13 (not shown) are sequentially arranged near the end of the treated water conveyance pipe. The outlet thermometer detects the temperature of the fluid in the treated water carrying pipe and outputs the detection result to the programmable sequencer of the control unit. The programmable sequencer controls the drive of the heat exchange pump so that the detection result by the outlet thermometer is below a predetermined upper limit temperature. Specifically, when the detection result by the outlet thermometer reaches a predetermined upper limit temperature, the amount of heat exchange fluid supplied to the heat exchanger 11 is increased by increasing the drive amount of the heat exchange pump, thereby exchanging heat. The cooling function by the vessel 11 is enhanced. Thus, the liquid is caused to flow into the heat exchanger 11 in a state where the temperature is equal to or lower than the upper limit temperature.

  A heat exchange thermometer (not shown) that detects the temperature of the heat exchange fluid immediately after passing through the heat exchanger 9 is provided in the vicinity of the heat exchanger 11. The temperature of the heat exchange fluid immediately after passing through the heat exchanger 11 is preferably equal to or higher than a predetermined lower limit temperature. Therefore, the programmable sequencer of the control unit controls the drive of the heat exchange pump so that the detection result by the heat exchange thermometer is below a predetermined lower limit temperature. Specifically, when the detection result by the heat exchange thermometer decreases to a predetermined lower limit temperature, the amount of heat exchange fluid supplied to the heat exchanger 11 is decreased by decreasing the drive amount of the heat exchange pump. Thereby, the temperature of the heat exchange fluid immediately after passing through the heat exchanger 11 is raised. However, the adjustment of the drive amount of the heat exchange pump based on the detection result by the outlet thermometer is prioritized over the adjustment of the drive amount of the heat exchange pump based on the detection result by the heat exchange thermometer. For this reason, when the detection result by the outlet thermometer is equal to or higher than the predetermined upper limit temperature and the detection result by the heat exchange thermometer is equal to or lower than the predetermined lower limit temperature, the driving amount based on the former detection result The driving amount is increased by prioritizing the adjustment.

  When the organic matter concentration in the wastewater is relatively high, a large amount of heat is generated by the oxidative decomposition of the organic matter. For this reason, although the heater 30 is operated at the initial stage of operation, after the oxidative decomposition of the organic matter is started, the temperature of the mixed fluid of the waste water and the hydrogen peroxide solution is set to a desired temperature by the heat generated by the oxidative decomposition of the organic matter. In some cases, the temperature can be naturally increased to a temperature of. The reaction tank 20 includes a first thermometer 21, a second thermometer 22, a third thermometer 23, and a fourth thermometer 24 that sequentially detect the temperature of the internal mixed fluid from the upstream side to the downstream side in the fluid conveyance direction. The fifth thermometer 25 is provided. The programmable sequencer of the control unit turns off the heater 30 as the heating means when the detection result by the thermometer becomes higher than a predetermined temperature. Thereby, useless energy consumption can be suppressed.

  In the treated water transport pipe, the water in the purified mixed fluid is cooled to change the state from the supercritical state or the high temperature / high pressure vapor state to the liquid state. On the other hand, oxygen and nitrogen in the mixed fluid change the mode from the supercritical state to the gas state. The mixed fluid that has passed through the treated water conveyance pipe is separated into treated water and gas by the gas-liquid separator 14, and the treated liquid is stored in the treated liquid tank. Gas is also released into the atmosphere.

  The treated water contains almost no suspended solids or organic matter because hardly decomposable organic matter such as phenol that cannot be removed by biological treatment with activated sludge is almost completely oxidized and decomposed. It contains only a small amount of inorganic material that could not be oxidized. Even as it is, it can be reused as industrial water depending on the application. Further, if a filtration process using an ultrafiltration membrane is performed, it can be diverted to an LSI cleaning liquid or the like. The gas separated by the gas-liquid separator 14 is mainly composed of carbon dioxide, nitrogen, and oxygen gas.

Next, a characteristic configuration of the fluid purification device according to the embodiment will be described.
FIG. 2 is a longitudinal sectional view showing the reaction tank 20. An arrow A direction in the figure indicates a fluid conveyance direction in which the fluid advances in the reaction tank 20. An inflow pipe 16 is connected to the upstream end of the reaction tank 20 in the fluid conveyance direction by a flange. A region (upstream end portion) (not shown) of the inflow pipe 16 is a merging portion 9. Moreover, the treated water conveyance pipe | tube 17 is connected to the downstream edge part of the fluid conveyance direction of the reaction tank 20 by the flange. The processing fluid processed in the reaction tank 20 is discharged from the reaction tank 20 to the treated water transport pipe 17.

  In the reaction tank 20, the first catalyst cartridge 26, the second catalyst cartridge 27, and the third catalyst cartridge 28 are arranged in order from the upstream side to the downstream side in the fluid conveyance direction. The mixed fluid (waste water + hydrogen peroxide solution) that has entered the reaction tank 20 from the inflow pipe 16 sequentially passes through the first catalyst cartridge 26, the second catalyst cartridge 27, and the third catalyst cartridge 28 while being heated and pressurized. To do. In this process, organic matter and ammonia nitrogen are gradually oxidized and decomposed.

  FIG. 3 is an exploded perspective view showing the reaction tank 20. The tank body 20a of the reaction tank 20 has a cylindrical shape, and is provided with flanges at the upstream end and the downstream end in the fluid conveyance direction (arrow A direction in the figure). By removing either the inflow pipe 16 or the treated water transfer pipe 17 from the tank body 20a, the first catalyst cartridge 26, the second catalyst cartridge 27, and the third catalyst cartridge 28 inserted into the tank body 20a are removed. The tank body 26a can be taken out. The first catalyst cartridge 26 includes a cylindrical first catalyst container 26a and a first catalyst 26b filled therein. The second catalyst cartridge 27 includes a cylindrical second catalyst container 27a and a second catalyst 27b filled therein. The third catalyst cartridge 27 includes a cylindrical third catalyst container 28a and a third catalyst 28b filled therein.

  Each of the first catalyst container 26a, the second catalyst container 27a, and the third catalyst container 28a is made of an alloy containing at least one of stainless steel, nickel, alumina, and zirconia. In the tank body 20a, hydrochloric acid derived from the chloro group of the organic chloride and sulfuric acid derived from a sulfonyl group such as an amino acid are generated as intermediate products, and the mixed fluid becomes strongly acidic. For this reason, what consists of the above alloys excellent in corrosion resistance is used as each catalyst container. Thereby, corrosion of each catalyst container can be suppressed.

  In the three catalyst cartridges (26, 27, 28), the catalyst (26b, 27b, 28b) is accommodated in the catalyst container (26a, 27a, 28a), and the reaction tank is integrated with the catalyst container. It is made detachable with respect to 20 tank main bodies 20a. In such a configuration, even if the catalyst has a complicated shape, it can be easily and safely attached to and detached from the tank body 20a by storing it in the catalyst container.

  Each of the first catalyst 26b, the second catalyst 27b, and the third catalyst 28b has a parallel pipe structure in which a plurality of tubular spaces are arranged in a direction orthogonal to the longitudinal direction, and the longitudinal direction is defined as a fluid conveyance direction (see FIG. The catalyst container (26a, 27a, 28a) is arranged in a posture along the direction of the middle arrow A). The tube wall constituting the wall of the tubular space functions as a catalyst, and the tube wall is composed of a base material made of metal and a catalyst layer made of a catalyst material coated on the surface thereof. . When the mixed fluid moves while contacting the catalyst layer on the tube wall, oxidative decomposition of the organic matter in the mixed fluid is promoted. Since the density of the tubular space increases in the order of the first catalyst 26b, the second catalyst 27b, and the third catalyst 28b, the surface area per unit area in the fluid transport direction of the catalyst increases in that order. . Therefore, in the fluid purification device according to the embodiment, the surface area per unit length of the catalyst decreases from the downstream side in the fluid conveyance direction toward the upstream side. Thereby, the catalytic ability of the catalyst in the fluid conveyance direction in the reaction tank 20 becomes lower from the downstream side toward the upstream side.

  In such a configuration, the upstream portion in the fluid conveyance direction of the reaction tank 20 has a lower catalytic ability of the catalyst than the middle flow portion and the downstream portion, so that the amount of organic matter that is oxidatively decomposed in the upstream portion is higher than in the conventional case. This also reduces the amount of heat generated in the upstream part. On the other hand, the amount of organic matter that is oxidatively decomposed in the middle stream portion or the downstream portion is higher in the middle stream portion or downstream portion in the fluid conveyance direction of the reaction tank 20 than the upstream portion because the catalytic ability of the catalyst is higher. However, the amount of heat generation in the midstream portion and downstream portion increases as compared with the conventional case. In this way, the upstream portion, the midstream portion, and the downstream portion of the reaction tank 20 are made uniform in calorific value, and the temperature rise temperature of the upstream portion is made lower than before, so that the heat of the reaction tank 20 is increased. Fatigue due to expansion and contraction can be suppressed more than before.

  In the reaction tank 20, the example in which the catalyst is disposed in the entire area in the fluid conveyance direction has been described. However, the catalyst is disposed only in the midstream region and the downstream region without disposing the catalyst in the upstream region. May be.

  As described above, the first catalyst 26b, the second catalyst 27b, and the third catalyst 28b are composed of a base material made of metal and a catalyst layer made of a catalyst material coated on the surface thereof. In such a configuration, the surface area of the catalyst can be easily and accurately adjusted by accurately processing the shape of the tube wall forming the skeleton of the catalyst with the base material made of metal.

  In the three catalyst cartridges, the first catalysts 26b, 27b, and 28b having different surface areas are accommodated in different catalyst containers (26a, 27a, and 28a) and individually attached to and detached from the tank body 20a. It is like that. In such a configuration, each catalyst can be easily replaced individually depending on the degree of contamination or deterioration.

  In the first catalyst 26b, the second catalyst 27b, and the third catalyst 28b, the catalyst material of the catalyst layer is Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Ni, Co, Ce, Of Ti and Mn, those made of a compound containing at least one of them are used. In such a configuration, the oxidative decomposition of organic matter and ammonia nitrogen can be favorably promoted by the combined portion.

  As the tank body 20a of the reaction tank 20, a corrosion-resistant layer made of an alloy containing at least one of Ti, Ta, Au, Pt, Ir, Rh, and Pd is provided on the inner peripheral surface of the cylindrical structure. The coated one is used. Even if hydrochloric acid or sulfuric acid, which is an oxidative decomposition product of organic matter, is generated, corrosion of the inner wall of the tank body 20a can be suppressed over a long period of time.

  In the tank body 20a, the base material forming the skeleton of the cylindrical structure is made of stainless steel, nickel, or an alloy containing at least one of them. In such a configuration, desired heat resistance and pressure resistance can be exhibited for the tank body 20a used under high temperature and high pressure conditions.

Next, experiments conducted by the present inventors will be described.
The present inventors prepared a fluid purification experimental apparatus having the same configuration as the fluid purification apparatus according to the embodiment. And the purification test of the experimental wastewater was done using this fluid purification experimental apparatus. In addition, as the reaction tank 20, what has a full length of 240 [mm] was used. Then, the first thermometer 21, the second thermometer 22, the third thermometer 23, the fourth thermometer 24, and the fifth thermometer 25 are connected to the upstream end (inlet) of the reaction tank 20, 20, 70, 120, 170. , 220 [mm].
[Experiment 1]
An aqueous methanol solution was prepared as experimental wastewater. Moreover, hydrogen peroxide water was prepared as an oxidizing agent. First, pure water was put into the raw water tank 1 and the oxidant tank 7, and pure water was pumped to the mixing unit 9 by the raw water supply pump 3 and the oxidant pump 6. Then, the pressure adjusting screw of the outlet valve 13 is adjusted while sending pure water from the mixing unit 9 into the reaction tank 20 to fill the reaction tank 20 with pure water, and the pressure in the reaction tank 20 is set to 10 [MPa]. Up to. Thereafter, the heater 30 was turned on, and the temperature of pure water in the reaction vessel 20 was increased to 400 [° C.]. Next, the pure water in the oxidant tank 7 is replaced with hydrogen peroxide water as an oxidant, and the reaction tank is preheated by the oxidant preheater 5 upstream of the mixing unit 9 with the hydrogen peroxide water. 20 was pumped. Then, when 1 hour passed, the pure water in the raw | natural water tank 1 was replaced with the methanol aqueous solution as experiment wastewater, and the oxidative decomposition process of methanol was started. At this time, in the mixing unit 9, the methanol concentration in the mixed fluid of the aqueous methanol solution and the hydrogen peroxide solution becomes 8 [wt%], the mixed fluid is retained in the reaction tank (20) for 20 seconds, and the peroxide is oxidized. The hydrogen peroxide solution and the aqueous methanol solution were pumped to the mixing unit 9 under the condition that the amount of oxygen generated from the hydrogen water was 1.5 times the stoichiometric amount necessary for complete oxidative decomposition of methanol. While the aqueous methanol solution was oxidatively decomposed in the reaction vessel 20 under such conditions, the treatment fluid discharged from the reaction vessel 20 was gas-liquid separated to obtain treated water. When the methanol concentration of the treated water was measured, it was almost zero. After confirming that the temperature in the reaction vessel 20 rose to around 450 [° C.] with various thermometers, the heater 30 was turned off and heating by the heater 30 was stopped. After that, it was confirmed that the temperature in the reaction vessel 20 did not decrease due to heat generation as the methanol was oxidatively decomposed.

  When 2 hours had passed since the start of the pumping of the methanol aqueous solution, the temperature in the reaction vessel 20 was measured by each thermometer. The result is shown in FIG. As shown in the figure, the fluid temperature at each position in the reaction tank 20 was 400 [° C.] before the start of processing, which is the timing immediately before starting the pumping of the aqueous methanol solution. This is a natural result because the heater 30 was uniformly heated to 400 [° C.]. On the other hand, after 2 hours, the fluid temperature at each position has increased to 450 [° C.]. Due to the heat generated by the oxidative decomposition of methanol, the temperature of the fluid naturally rose to 450 [° C.] without heating by the heating means. It should be noted that the fluid temperature at each position (20, 70, 120, 170, 220 mm) is stable at 450 [° C.]. This confirms that the oxidative decomposition reaction of methanol occurred uniformly in the longitudinal direction (fluid conveyance direction) of the reaction tank 20.

[Experiment 2]
The first catalyst cartridge 26, the second catalyst cartridge 27, and the third catalyst cartridge 28 were taken out from the reaction tank 20 of the fluid purification experimental apparatus. Then, three new third catalyst cartridges 28 were set in the reaction tank 20. That is, three third catalyst cartridges 28 having the same catalyst surface area are arranged side by side.

  In the same manner as in Experiment 1, an oxidative decomposition test of an aqueous methanol solution was performed. The temperature measurement results at each position in the reaction vessel 20 are shown in FIG. As shown in the figure, after 2 hours from the start of the treatment, the temperature of the fluid rose to 520 [° C.] at the first position closest to the inlet of the reaction tank 20 (a point 20 mm from the inlet). In addition, the fluid temperature rose to 500 [° C.] at the second position closest to the inlet (a point 70 mm from the inlet). In contrast, at the third position, the fourth position, and the fifth position (120 mm spot, 170 mm spot, and 220 mm spot from the entrance), the temperature of the fluid was around 400 [° C.]. This confirms that the temperature of the upstream region has become higher than that of the downstream region as a result of the oxidative decomposition reaction of methanol being actively performed in the upstream region of the downstream region of the reaction tank 20. ing. From this result, it was proved that by reducing the surface area of the catalyst from the downstream side toward the upstream side (Experiment 1), the amount of methanol oxidative decomposition reaction can be made uniform.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
[Aspect A]
Aspect A is a process in which an organic substance in the purification target fluid is oxidized and decomposed in the process of sending the purification target fluid and the oxidant received therein and mixing from the front end side to the rear end side. A reaction tank (for example, the reaction tank 20) for purifying the fluid, and a catalyst (for example, the first catalyst 26b, the second catalyst 27b, the third catalyst) disposed in the reaction tank to promote the oxidative decomposition of the organic matter. In the fluid purification device including the catalyst 28b), the catalytic ability of the catalyst in the fluid conveyance direction in the reaction tank is lowered from the downstream side toward the upstream side.

[Aspect B]
Aspect B is that in Aspect A, the surface area per unit length of the catalyst is reduced from the downstream side to the upstream side in the fluid conveyance direction, so that the catalytic ability is reduced from the downstream side to the upstream side. It is characterized by that. In such a configuration, the catalytic ability of the catalyst can be easily and accurately adjusted by varying the surface area of the catalyst in the fluid conveyance direction.

[Aspect C]
Aspect C is characterized in that in Aspect B, a catalyst comprising a base material and a catalyst layer made of a catalyst material coated on the surface thereof is used as the catalyst. In such a configuration, the surface area of the catalyst can be easily and accurately adjusted by accurately processing the shape of the tube wall forming the skeleton of the catalyst with the base material made of metal.

[Aspect D]
So far, in the fluid conveyance direction, the aspect in which the catalytic ability is made different by changing the surface area of the catalyst has been described. However, as in the following aspect D, the catalytic ability is made different by making the type of the catalyst different. Also good. That is, in the aspect D, in the aspect A, as the catalyst, a catalyst material having a lower catalytic ability arranged in the order from the downstream side to the upstream side in the fluid conveyance direction is used. It is characterized by being lowered from the downstream side toward the upstream side. In such a configuration, it is possible to change the catalytic ability without changing the surface area of the catalyst, and therefore it is not necessary to strictly adjust the surface area of the catalyst. For this reason, a simple configuration in which granular catalyst particles are filled can be employed.

  Note that the catalytic ability of the catalyst material varies depending on the type of organic matter to be oxidatively decomposed. The catalytic ability in the aspect D is catalytic ability with respect to the organic substance present in the highest concentration among the organic substances contained in the purification target fluid. For example, the relationship between the catalytic ability for methane and the catalyst material is Pd> Pt> Co> Cr> Mn> Cu> Ce> Fe> V> Ni> Mo> Ti.

[Aspect E]
Aspect E is any one of the aspects A to D, wherein the catalyst is accommodated in a catalyst container (for example, the first catalyst container 26a, the second catalyst container 27a, and the third catalyst container 28a). It is characterized in that it can be attached to and detached from the reaction tank integrally with the container. In such a configuration, even if the catalyst has a complicated shape, it can be easily and safely attached to and detached from the reaction vessel by storing it in the catalyst container.

[Aspect F]
In aspect F, in aspect E, the catalysts having different surface areas or the catalysts having different types of catalyst materials are accommodated in the catalyst containers different from each other and individually attached to and detached from the reaction vessel. It is characterized by that. In such a configuration, a catalyst having a different surface area or a catalyst having a different type of catalyst material can be easily replaced individually depending on the degree of contamination or deterioration.

[Aspect G]
Aspect G is characterized in that in Aspect E or F, the catalyst container is one containing at least one of stainless steel, nickel, alumina, and zirconia. In such a configuration, the occurrence of corrosion of the catalyst container can be suppressed.

[Aspect H]
Aspect H is any one of aspects A to G, wherein the catalyst material is Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Ni, Co, Ce, Ti, and Mn as the catalyst. Of these, a compound comprising a compound containing at least one of them is used. In such a configuration, the oxidative decomposition of organic matter and ammonia nitrogen can be favorably promoted by the combined portion.

[Aspect I]
In the aspect I, in any one of the aspects A to H, as the reaction tank, a corrosion-resistant layer made of an alloy containing at least one of Ti, Ta, Au, Pt, Ir, Rh, and Pd is provided inside. It is characterized by using a coated one. In such a configuration, even if hydrochloric acid or sulfuric acid, which is an oxidative decomposition product of organic matter, is generated by the corrosion resistant layer, corrosion of the inner wall of the reaction tank can be suppressed for a long period of time.

[Aspect J]
Aspect J is characterized in that, in aspect I, the base material of the reaction vessel is made of stainless steel, nickel, or an alloy containing at least one of them. With such a configuration, desired heat resistance and pressure resistance can be exhibited in a reaction vessel used under high temperature and high pressure conditions.

20: reaction tank 26: first catalyst cartridge 26a: first catalyst container 26b: first catalyst 27: second catalyst cartridge 27a: second catalyst container 27b: second catalyst 28: third catalyst cartridge 28a: third Catalyst container 28b: third catalyst

JP 2001-205279 A

Claims (10)

Purifying the purification target fluid by oxidizing and decomposing organic matter in the purification target fluid in the process of sending the purification target fluid and the oxidant received in the inside from the leading end side to the rear end side while mixing the oxidant. In a fluid purification device comprising a reaction tank for the purpose and a catalyst disposed in the reaction tank to promote oxidative decomposition of organic matter,
The fluid purification apparatus according to claim 1, wherein the catalytic capacity of the catalyst in the fluid conveyance direction in the reaction tank is lowered from the downstream side toward the upstream side. The fluid purification device according to claim 1,
The fluid purification, wherein the surface area per unit length of the catalyst is reduced from the downstream side to the upstream side in the fluid conveyance direction, and the catalytic ability is reduced from the downstream side to the upstream side. apparatus. The fluid purification apparatus according to claim 2, wherein
A fluid purifying apparatus comprising a substrate and a catalyst layer made of a catalyst material coated on a surface of the substrate as the catalyst. The fluid purification device according to claim 1,
As the catalyst, a catalyst material of a type having a lower catalytic ability is arranged as it goes from the downstream side to the upstream side in the fluid conveyance direction, so that the catalytic ability is lowered as it goes from the downstream side to the upstream side. The fluid purification apparatus characterized by the above-mentioned. The fluid purification device according to any one of claims 1 to 4,
A fluid purification apparatus characterized in that the catalyst is accommodated in a catalyst container and is detachable from the reaction tank integrally with the catalyst container. The fluid purification device according to claim 5, wherein
Fluid purification, characterized in that catalysts having different surface areas or different types of catalyst materials are accommodated in the catalyst containers different from each other and individually attached to and detached from the reaction vessel. apparatus. The fluid purification device according to claim 5 or 6,
A fluid purifier using at least one of stainless steel, nickel, alumina, and zirconia as the catalyst container. The fluid purification device according to any one of claims 1 to 7,
As the catalyst, the catalyst material is made of a compound containing at least one of Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Ni, Co, Ce, Ti, and Mn. A fluid purification device characterized by using the above. The fluid purification device according to any one of claims 1 to 8,
A fluid characterized in that as the reaction tank, a corrosion-resistant layer made of an alloy containing at least one of Ti, Ta, Au, Pt, Ir, Rh, and Pd is coated. Purification equipment. The fluid purification device according to claim 9, wherein
A fluid purification apparatus using a material made of stainless steel, nickel, or an alloy containing at least one of them as a base material of the reaction vessel.

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