JP6016082B2 - Fluid purification device - Google Patents

Description

  The present invention provides an oxidative decomposition reaction of organic matter in a mixed fluid while heating and pressurizing the mixed fluid obtained by mixing the fluid to be purified and the oxidant received therein and changing it to a state different from the liquid. The present invention relates to a fluid purification device including a reaction tank for generating water.

  Conventionally, as a method for purifying wastewater such as human waste, sewage, settlement wastewater, livestock manure, food factory wastewater, a method of performing biological treatment using activated sludge has been generally used. However, with this method, it has been impossible to treat high-concentration organic solvent wastewater that hinders the activity of microorganisms in activated sludge at the same concentration or wastewater containing plastic fine particles that cannot be biodegraded. In addition, it has not been possible to treat wastewater containing a large amount of hardly decomposable organic substances, such as oil, which are slow to decompose by microorganisms.

  On the other hand, in recent years, development of fluid purification devices that purify wastewater by oxidizing and decomposing organic matter in the mixed fluid while heating and pressurizing the mixed fluid of wastewater and oxidant such as air has been performed. In this type of fluid purification device, the organic substance in the mixed fluid is chemically oxidized and decomposed by heating and pressurizing the mixed fluid of the wastewater and the oxidizing agent in the reaction tank. In such oxidative decomposition, high-concentration organic solvent wastewater, plastic fine particle-containing wastewater, hardly-decomposable organic matter-containing wastewater, and the like, which could not be obtained by biological treatment, can be purified well.

  As such a fluid purification device, the one described in Patent Document 1 is known. This fluid purification device pumps a liquid to be treated which is a fluid to be purified and air which is an oxidant into a reaction tank. And the mixed fluid of a to-be-processed liquid and air is heated and pressurized in a reaction tank, and the water in a mixed fluid is made into a supercritical state or a subcritical state. Supercritical water has a property intermediate between liquid and gas, and appears under conditions where the temperature exceeds the critical temperature of water and the pressure exceeds the critical pressure of water. Subcritical water is water in a state closer to a liquid than supercritical water, and appears under conditions where the temperature exceeds the critical temperature of water and the pressure is slightly lower than the critical pressure of water.

  In the reaction tank, organic substances dissolve and hydrolyze in an instant in a fluid mixture of supercritical water or subcritical water and air, or oxidatively decompose organic substances in the presence of oxygen in an instant. Or In addition, ammonia nitrogen is decomposed and converted to nitrogen gas.

  In a reaction tank in which such an oxidative decomposition reaction of organic matter occurs, the solubility of inorganic salts generated with the purification of the liquid to be treated is low, so that inorganic salts are deposited and adhere to the inner wall of the reaction tank. When the solid matter made of inorganic salts grows on the inner wall, the inner wall of the reaction tank is corroded or the fluid flow in the reaction tank is hindered. For this reason, although it is necessary to clean the inside of a reaction tank regularly, in cleaning, it is necessary to reduce the pressure of the fluid in a reaction tank. At this time, when the fluid in the reaction tank is changed from the supercritical state or the subcritical state to the liquid state, the solubility of the inorganic salts increases and the inorganic salts are dissolved into the liquid to become inorganic acids. The liquid containing the inorganic acid promotes corrosion of the inner wall of the reaction tank.

  Therefore, in the fluid purification device described in Patent Document 1, prior to lowering the pressure in the reaction tank, a drying gas is pumped into the reaction tank, and the mixed fluid in the reaction tank is converted into a drying gas. Replace. By such a process (hereinafter referred to as a pre-reaction tank pretreatment process), the reaction tank is cleaned after the inner wall of the reaction tank is dried. According to such a configuration, it is possible to avoid the occurrence of corrosion in the reaction tank due to the liquid mixture becoming liquid in the reaction tank prior to cleaning.

  However, in this fluid purification apparatus, when the organic substance of the mixed fluid is oxidatively decomposed in the reaction tank, there is a possibility that the reaction tank may be corroded to cause damage to the reaction tank due to the corrosion. Specifically, in the reaction tank, sulfuric acid is generated in the process of oxidizing and decomposing organic substances having a sulfonyl group, and hydrochloric acid is generated in the process of oxidizing and decomposing organic substances having a chloro group. Such sulfuric acid or hydrochloric acid may cause the reaction tank to rapidly corrode and cause damage to the reaction tank.

  Therefore, the present inventors are developing a fluid purification device in which the region in contact with the mixed fluid in the reaction tank is made of titanium having excellent corrosion resistance. According to the fluid purification device under development, even if sulfuric acid or hydrochloric acid is generated in the reaction tank, the area of the reaction tank that touches them (hereinafter referred to as the titanium area) has excellent corrosion resistance against sulfuric acid and hydrochloric acid. Since it is made of titanium that exhibits, the occurrence of damage to the reaction tank due to sulfuric acid or hydrochloric acid can be suppressed. Specifically, titanium is oxidized upon contact with oxygen to form a passive film. This passive film on the surface of titanium exhibits excellent corrosion resistance.

  However, in this fluid purification device, if the reaction tank is cleaned immediately after the amount of sulfuric acid or hydrochloric acid generated suddenly increases due to a temporary inflow of wastewater containing a large amount of organic matter, There was a possibility that the titanium region was partially corroded by the cleaning liquid. Specifically, since the oxidizing agent is pumped into the operating reaction vessel and oxygen is abundant, a passive film is formed on the surface of the titanium region. When this passive film comes into contact with high-concentration sulfuric acid or hydrochloric acid, the passive film dissolves and is lost. If a large amount of sulfuric acid or hydrochloric acid is temporarily generated in a local area in the reaction tank due to a temporary inflow of wastewater containing a large amount of organic matter, the passive film in the titanium area near the local area can be dissolved. . Thereby, in the state where the loss of the partial passive film has occurred on the surface of the titanium region, when the pretreatment treatment before the reaction vessel cleaning is started and a drying gas such as nitrogen is introduced into the reaction vessel, Loss of the passive film in the titanium region of the reaction vessel remains in a state where the passive film has been lost. When the cleaning agent is introduced into the reaction tank in this state, the titanium in the lost portion of the passive film directly corrodes with the inorganic acid eluted in the cleaning agent, resulting in corrosion.

  It should be noted that the present invention is not limited to the case where the mixed fluid is brought into the supercritical state or the subcritical state in the reaction tank as in the fluid purification device described in Patent Document 1 to generate an oxidative decomposition reaction of organic matter, but in the following cases: However, similar problems can occur. That is, it is a case where the mixed fluid is brought into a high-temperature and high-pressure steam state in the reaction tank to generate an oxidative decomposition reaction of organic matter.

  This invention is made | formed in view of the above background, The place made into the objective is providing the following fluid purification apparatuses. That is, the occurrence of corrosion of the reaction tank when the organic matter of the mixed fluid is oxidatively decomposed in the reaction tank is suppressed, and the corrosion of the reaction tank due to the inorganic acid eluted in the cleaning agent used for cleaning the reaction tank is suppressed. This is a fluid purification device capable of suppressing generation.

  In order to achieve the above object, the present invention performs mixing while heating and pressurizing a mixed fluid obtained by mixing a fluid to be purified received inside itself and an oxidant to change it into a state different from the liquid. A reaction tank for generating an oxidative decomposition reaction of an organic substance in the fluid; a pre-purification fluid pumping means for pumping the fluid to be purified into the reaction tank; and an oxidant pumping pumping the oxidant into the reaction tank. Means, gas pumping means for pumping a predetermined gas into the reaction tank, pressure adjusting means for adjusting the pressure of the fluid in the reaction tank, pre-purification fluid pumping means, the oxidant pumping means, Gas pressure feeding means, and control means for controlling the drive of the pressure adjusting means, and mixing in the process of sending the mixed fluid in the reaction tank from one end side to the other end side in the longitudinal direction of the reaction tank Oxidative decomposition of organic substances in the fluid The purified fluid purified by the solution is discharged from the other end in the longitudinal direction of the reaction tank, and the control means is prepared by the pre-purification fluid pressure feeding means as a preparation before carrying out cleaning in the reaction tank. In a state where the pumping of the fluid to be treated is stopped, the gas is pumped to the reaction tank by the gas pumping means, the fluid inside the reaction tank is made only the gas, and then the reaction is performed by the pressure adjusting means. In the fluid purification apparatus that performs pre-cleaning preparatory processing for reducing the gas pressure in the tank, the region in contact with the mixed fluid in the reaction tank is made of titanium, and in the pre-cleaning preparatory processing, The present invention is characterized in that a passive film regeneration means for regenerating the passive film at the location where the passive film is lost on the titanium surface of the reaction tank is provided.

  In the present invention, even if sulfuric acid or hydrochloric acid is generated during the oxidative decomposition of the organic matter of the mixed fluid in the reaction tank, the region of the reaction tank that touches them exhibits excellent corrosion resistance against sulfuric acid and hydrochloric acid. Therefore, it is possible to suppress the occurrence of damage to the reaction tank due to sulfuric acid or hydrochloric acid. Therefore, it is possible to suppress the occurrence of corrosion in the reaction tank when the organic substance of the mixed fluid is oxidatively decomposed in the reaction tank.

  Further, in the present invention, in the pre-cleaning preparatory process, the passive film loss portion in the titanium region of the reaction vessel is oxidized by the passive film regeneration means to regenerate the passive film. In such a configuration, even if there is a place where the passive film is lost, the reaction tank is cleaned after regenerating the passivated film, so that it contains sulfuric acid and hydrochloric acid. Occurrence of corrosion in the reaction tank due to contact of the cleaning agent with the location where the passive film is lost 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 feed double pipe of the fluid purification apparatus. The longitudinal cross-sectional view which shows the reaction tank of the fluid purification apparatus. The longitudinal cross-sectional view which shows the connection part of the feed conveyance pipe and reaction tank of the fluid purification apparatus. The longitudinal cross-sectional view which shows the connection part of the reaction tank of a fluid purification apparatus, and a conveyance pipe. The flowchart which shows each process of the pre-cleaning preparatory process implemented by the programmable sequencer of the fluid purification apparatus. The flowchart which shows each process of the washing process implemented by the programmable sequencer of the fluid purification apparatus.

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 pressure gauge 4, a raw water inlet valve 5, an oxidant pressure feed pump 6, an oxidant pressure gauge 7, an oxidant inlet valve 8, and heat. An exchanger 9, a heat medium tank 10, a heat exchange pump 11, and the like are provided. Moreover, the outlet pressure gauge 12, the outlet valve 13, the feed double pipe 15, the transport pipe 16, the reaction tank 20, the reaction tank heater 23, the thermometer 24, the raw water tank valve 30, the first fresh water tank 31, and the first fresh water tank A valve 32, a preheating heater 33, and the like are also provided. Further, a heat medium valve 34, a second fresh water tank 35, a second fresh water tank valve 36, a pressure equalizing water pump 37, a pressure equalizing water valve 38, a pressure equalizing water pressure gauge 40, a pressure adjusting valve 41, a control unit (not shown), and the like. I have. Furthermore, a gas-liquid separator 45, a humidity measuring valve 46, a hygrometer 47, a gas ion chromatograph 48, a TOC (total organic carbon) measuring device 49, a liquid ion chromatograph 50, and the like are also provided.

  The control unit has a power feeding circuit composed of a combination of an earth leakage breaker, a magnet switch, a thermal relay, and the like for the devices listed next. That is, the stirrer 2, the raw water supply pump 3, the oxidant pressure feed pump 6, the heat exchange pump 11, the reaction tank heater 23, the raw water tank valve 30, the first fresh water tank valve 32, the preheating heater 33, the second fresh water tank valve 36, They are a pressure equalizing water pump 37 and a humidity measuring valve 46. 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 raw water pressure gauge 4, the oxidant pressure gauge 7, the outlet pressure gauge 12, and the pressure equalization water pressure gauge 40 each output a voltage having a value corresponding to the pressure detection result. Moreover, the thermometer 24 of the reaction tank 20 detects the temperature of the front end side region of the inner cylinder described later in the reaction tank and outputs a voltage corresponding 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. The waste water is composed of at least one of 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. A raw water tank 1 is connected to a raw water supply pump 3 composed of a high-pressure pump for pumping waste water through a raw water tank valve 30. A first fresh water tank 31 is also connected through a first fresh water tank valve 32. The raw water tank valve 30 and the first fresh water tank valve 32 are composed of motor valves, and can be automatically opened and closed by commands from the control unit. During normal operation, the first fresh water tank valve 32 is closed and the raw water tank valve 30 is opened. As a result, the raw water supply pump 3 sucks the waste water in the raw water tank 1 and pumps it toward the feed double pipe 15 described later.

  The raw water inlet valve 5 connected to the discharge pipe of the raw water supply pump 3 plays a role of a check valve, and the waste water pumped from the raw water supply pump 3 is supplied later from the raw water supply pump 3 side. While allowing flow to the double pipe 15 side, reverse flow is blocked.

  The oxidant pressure feed pump 6 composed of a compressor feeds air taken in as an oxidant to the feed double pipe 15 through the oxidant inlet valve 8 while compressing the air to a pressure similar to the inflow pressure of the waste water. The oxidant inlet valve 8 plays a role of a check valve, and allows the air fed from the oxidant pressure feed pump 6 to flow from the oxidant pressure feed pump 6 side to the feed double pipe 15 side. On the other hand, the reverse flow is blocked.

  As shown in FIG. 2, the feeding double pipe 15 has a double pipe structure including an outer pipe 15a and an inner pipe 15b disposed inside the outer pipe 15a. And the waste water W pumped from the raw | natural water supply pump (3 of FIG. 1) is received in the inner pipe 15b, and is made to flow in into the reaction tank (20 of FIG. 1) mentioned later. In addition, the air pumped from the oxidant pump (6 in FIG. 1) is received in the space between the inner tube 15b and the outer tube 15a, and flows into the reaction tank described later.

  In FIG. 1, the inflow pressure of wastewater by driving the raw water supply pump 3 is detected by a raw water pressure gauge 4 disposed upstream of the raw water inlet valve 5 and input as sensing data to a programmable sequencer of the control unit. The The inflow pressure of the waste water when the raw water supply pump 3 is driven and the pressure in the reaction tank 20 are substantially the same.

  The inflow pressure of the air generated by driving the oxidant pump 6 is detected by an oxidant pressure gauge 7 disposed upstream of the oxidant inlet valve 8 and input as sensing data to a programmable sequencer of the control unit. . The inflow pressure of air when the oxidant pressure gauge 7 is driven and the pressure in the reaction tank 20 are substantially the same.

  The amount of air pumped by driving 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, COD (Chemical Oxygen Demand) of wastewater, total nitrogen (TN), total phosphorus (TP), etc. are necessary for complete oxidation of organic matter based on organic matter concentration, nitrogen concentration, phosphorus concentration, etc. in wastewater W The amount of oxygen is calculated, and the pumping amount of air is set based on the result.

  The inflow of air is set by the worker, but the type of organic matter contained in the wastewater W is stable over time, and the physical properties such as turbidity, light transmittance, electrical conductivity, specific gravity, etc. When the correlation with the amount of oxygen is relatively good, the programmable sequencer is configured to perform the process of automatically correcting the above-mentioned control range based on the result of detecting the physical property by a sensor or the like. May be.

  As the oxidizing agent, in addition to air, any one of oxygen gas, ozone gas, hydrogen peroxide water, or a mixture of two or more of them can be used.

  As shown in FIG. 1, air flowing between the inner pipe (15b in FIG. 2) and the outer pipe (15a in FIG. 2) of the feeding double pipe 15 is formed on the outer surface of the feeding double pipe 15. A preheater 33 for preheating is attached. In the feed double pipe 15, the air flowing between the inner pipe and the outer pipe is preheated by the preheater 33 and then pumped into the reaction tank 20.

  FIG. 3 is a longitudinal sectional view showing the reaction tank 20. The reaction tank 20 has a double cylinder structure including an outer cylinder 21 and an inner cylinder 22 disposed inside thereof. The feeding double pipe 15 and the end of the outer cylinder 21 of the reaction tank 20 on the left side in the figure are connected by an inlet coupling 17. In the reaction tank 20, the feeding double pipe 15 communicates with the inner cylinder 22 of the reaction tank 20, but does not communicate with the inter-cylinder space between the inner cylinder 22 and the outer cylinder 21. It has become.

  The inner wall of the inner cylinder 22 is a region in contact with the mixed fluid in the reaction tank 20. The inner cylinder 22 is a cylinder made of acid-resistant titanium (Ti). Therefore, the region in contact with the mixed fluid in the reaction tank 20 is a titanium region.

  The outer cylinder 21 is a cylinder made of a metal material having excellent strength, such as stainless steel (SUS304, SUS316), Inconel 625, and nickel alloy. The pressure inside the reaction tank 20 is controlled to a high pressure of 0.5 to 30 MPa, desirably 5 to 30 MPa. The outer cylinder 21 is thick so that it can withstand such a high pressure. On the other hand, since the inner cylinder 22 is required to have corrosion resistance rather than pressure resistance, titanium that exhibits excellent corrosion resistance is adopted as a material.

  Waste water W that is pumped toward the reaction tank 20 in the inner pipe 15b of the feed double pipe 15 or the reaction tank 20 in the space between the inner pipe 15b and the outer pipe 15a of the feed double pipe 15 The air A pumped toward the inside flows into the left end portion in the figure in the inner cylinder 22 of the reaction tank 20. The waste water A and the air A move from the left side to the right side in the figure while being mixed with each other to form a mixed fluid.

  The outer cylinder 21 of the reaction tank 20 is formed with an equalized water inflow portion 21a and an equalized water discharge portion 21b. The equalized water inflow portion 21 a is for receiving equalized water sent from the outside in the inter-cylinder space between the inner cylinder 22 and the outer cylinder 21 of the reaction tank 20. Moreover, the equalized water discharge part 22b is for discharging equalized water out of the reaction tank 20 from the space between the cylinders.

  In FIG. 1, a pressure equalizing water pump 37 sucks the fresh water stored in the second fresh water tank 35 and the pressure equalizing water discharged from the inter-cylinder space between the inner cylinder and the outer cylinder of the reaction tank 20. Then, it is pumped to the inter-cylinder space of the reaction tank 20. The pressure-equalized water that has been pumped passes through the pressure-equalized water valve 38 that is a check valve, and then flows into the inter-cylinder space of the reaction tank 20.

  The equalized water flowing along the cylinder longitudinal direction in the inter-cylinder space of the reaction tank 20 is eventually discharged from the inter-cylinder space and goes out of the reaction tank 20. Then, after passing through the pressure regulating valve 41, the pressure is again sucked into the pressure equalizing water pump 37 and returned into the inter-cylinder space of the reaction tank 20.

  During normal operation, the second fresh water tank valve 36 interposed between the second fresh water tank 35 and the pressure equalizing water pump 37 is closed. The programmable sequencer determines that the pressure is higher than the first threshold when the pressure of the pressure equalized water detected by the pressure equalizing water pressure gauge 40 is higher than a predetermined second threshold and lower than the first threshold. The 2nd fresh water tank valve 36 which consists of a motor valve is opened until it becomes. Thus, a certain amount of equalized water flows through the equalized water circulation path including the inter-cylinder space of the reaction tank 20 and the equalized water pump 37.

  In FIG. 3, in the inner cylinder 22 of the reaction tank 20, as the organic matter in the waste water W is decomposed, hydrochloric acid derived from the chloro group of the organic chloride, sulfuric acid derived from the sulfonyl group such as amino acid, amino acid Nitric acid derived from an amino group such as the like may be generated, and the inner wall of the inner cylinder 22 may be placed under strong acidity. For this reason, a cylinder made of titanium having excellent corrosion resistance is adopted as the inner cylinder 22. However, since titanium is a very expensive material, if the thickness of the inner cylinder 22 is increased to a value that can withstand high pressure, the cost becomes very high. Therefore, the outer cylinder 21 is disposed outside the inner cylinder 22, and the required pressure resistance is exhibited by the outer cylinder 21 made of stainless steel or the like that is cheaper than titanium. The pressure in the inter-cylinder space between the inner cylinder 22 and the outer cylinder 21 is slightly higher than the pressure in the inner cylinder 22 due to the equalized water pumped into the inter-cylinder space. For this reason, a large pressure is not applied to the inner cylinder 22 made of thin titanium.

  Examples of the pressure applied to the mixed fluid in the inner cylinder 22 include a range of 0.5 to 30 MPa (desirably 5 to 30 MPa). The pressure in the inner cylinder 22 is adjusted by an outlet valve (13 in FIG. 1). When the pressure in the inner cylinder 22 becomes higher than the threshold value, the outlet valve automatically opens the valve and discharges the mixed fluid in the inner cylinder 22 to the outside, thereby maintaining the pressure in the inner cylinder 22 near the threshold value. To do.

  In addition to the high pressure, the mixed fluid in the inner cylinder 22 is at a high temperature. The temperature is 100 to 700 ° C, desirably 200 to 550 ° C. When the operation of the fluid purification device is started, the mixed fluid of the waste water W and the air A in the inner cylinder 22 is under pressure, but the temperature is not so high. Therefore, at the start of operation, the programmable sequencer causes the reaction tank heater (23 in FIG. 1) to generate heat, and raises the temperature of the mixed fluid in the inner cylinder 22 to 200 to 700 ° C.

  When the reaction tank heater is turned on, the heat is transferred to the mixed fluid in the inner cylinder 22 via the outer cylinder 21, the equalized water in the inter-cylinder space, and the inner cylinder 22. At the start of operation, the pressure equalizing water pump (37 in FIG. 1) is stopped in a state where a constant pressure is applied to the pressure equalizing water in the inter-cylinder space to stop the circulating conveyance of the equalized water. For this reason, the heat transmitted from the outer cylinder 21 to the equalized water in the inter-cylinder space is efficiently transmitted to the inner cylinder 22 and the mixed fluid in the inner cylinder 22.

  In FIG. 3, when the oxidative decomposition of the organic substance is started in the mixed fluid in the inner cylinder 22, heat is generated along with the oxidative decomposition. When the wastewater W 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 a large amount of organic matter is decomposed by oxidation. In this case, heating by the reaction tank heater 23 is performed only at the time of starting the apparatus, and the power to the reaction tank heater 23 can be turned off after the oxidative decomposition is started. Therefore, the programmable sequencer turns off the reaction tank heater 23 when the detection result by the thermometer (24 in FIG. 1) becomes equal to or higher than a desired temperature.

  In the case where a heat exchanger is provided on the outer peripheral surface of the outer cylinder 21, the temperature of the mixed fluid in the inner cylinder 22 can be adjusted also by turning the heat exchanger on and off.

  In the mixed fluid that moves the inner cylinder 22 from the left side to the right side in the drawing, the oxidative decomposition of the organic matter proceeds rapidly. The mixed fluid (W + A) that has moved to the vicinity of the right end of the inner cylinder 22 in the drawing is in a state in which organic substances and inorganic compounds are almost completely oxidized and decomposed. A transport pipe 16 is connected to the right end (rear end) of the reaction tank 20 through the outlet coupling 18. The mixed fluid purified by the oxidative decomposition of the organic matter is discharged from the inner cylinder of the reaction tank 20 to the transport pipe 16.

  When temperature = 374.2 ° C. or higher and pressure = 21.8 MPa or higher are adopted as conditions for the temperature and pressure in the inner cylinder 22, the critical temperature of water and the critical pressure are exceeded. Since the critical pressure is also exceeded, the mixed fluid becomes a supercritical fluid having intermediate properties 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.

  Further, as conditions for the temperature and pressure in the inner cylinder 22, a relatively high pressure of temperature = 200 ° C. or higher (preferably 374.2 ° C. or higher) and pressure = 21.8 MPa (preferably 10 MPa or higher) is adopted. Then, the waste water in the mixed fluid in the inner cylinder 22 may be converted into high-temperature and high-pressure steam.

  In the transport pipe 16, 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. Note that a corrosion resistant layer made of a metal material having excellent corrosion resistance is coated on the inner side of the transport pipe 16.

  In FIG. 1, a heat exchanger 9 is attached to the outer wall of the transfer pipe 16. The main body of the heat exchanger 9 is composed of an outer tube that covers the outer wall of the transfer tube 16, and a space between the outer tube and the outer wall of the transfer tube 16 is filled with a heat exchange fluid such as water. The heat exchanger 9 performs heat exchange between the outer wall of the transport pipe 16 and the heat exchange fluid.

  When the reaction tank 20 is operated, a very high-temperature liquid flows inside the transfer pipe 16, so heat is transferred from the transfer pipe 16 to the heat exchange fluid in the heat exchanger 9, and the heat exchange fluid is heated. The transport direction of the heat exchange fluid in the heat exchanger 9 is opposite to the transport direction of the liquid in the transport pipe 16 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 the heat exchange pump 11 that sends the heat exchange fluid in the heat medium tank 10 to the heat exchanger 9 while sucking the heat exchange fluid.

  The heat exchange fluid heated through the heat exchanger 9 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. A part of the heat exchange fluid that has passed through the heat exchanger 9 may be conveyed to the inflow pipe 26 or the raw water tank 1 by a branch pipe and used for preheating the waste water W.

  In the vicinity of the outlet valve 13, an outlet thermometer (not shown) that detects the temperature of the transport pipe 16 or the temperature of the liquid in the transport pipe 16 is provided. The programmable sequencer of the control unit controls the drive of the heat exchange pump 11 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 9 is increased by increasing the drive amount of the heat exchange pump 11, The cooling function by the exchanger 9 is enhanced. Accordingly, the liquid is caused to flow into the heat exchanger 9 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 9. The temperature of the heat exchange fluid immediately after passing through the heat exchanger 9 is preferably equal to or higher than a predetermined lower limit temperature. Therefore, the programmable sequencer of the control unit controls the driving of the heat exchange pump 11 so that the detection result by the heat exchange thermometer is equal to or lower than 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 9 is decreased by decreasing the drive amount of the heat exchange pump 11. Thereby, the temperature of the heat exchange fluid immediately after passing through the heat exchanger 9 is raised. However, the adjustment of the drive amount of the heat exchange pump 11 based on the detection result by the outlet thermometer is prioritized over the adjustment of the drive amount of the heat exchange pump 11 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 W is relatively high, a large amount of heat is generated by oxidative decomposition of the organic matter. For this reason, although the reaction vessel heater 23 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 waste water and air is set to a desired value by the heat generated by the oxidative decomposition of the organic matter. In some cases, the temperature can be naturally increased to the temperature. Therefore, the programmable sequencer of the control unit sets the reaction tank heater 23 as a heating means when the detection result by the thermometer 24 that detects the temperature of the distal end side region of the inner cylinder 22 becomes higher than a predetermined temperature. Turn off. Thereby, useless energy consumption can be suppressed.

  The mixed fluid that has passed through the transport pipe 16 is separated into treated water and gas by the gas-liquid separator 45, and the treated water is stored in a treated water tank (not shown). 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 only contains minerals that cannot 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.

  FIG. 4 is a longitudinal sectional view showing a connection portion between the feeding / conveying pipe 15 and the reaction tank 20. The feed pipe 1 and the reaction vessel 20 are connected by an inlet coupling 17. The outer pipe 15a and the inner pipe 15b in the feeding / conveying pipe 15 are separated from each other, and the inner pipe 15b inserted into the outer pipe 15a is passed through the hole of the inlet coupling 17 so that the inlet coupling 17 is held.

  FIG. 5 is a longitudinal sectional view showing a connection portion between the reaction tank 20 and the transfer pipe 16. In the same figure, the discharge side wall is provided in the attitude | position which extends in the cylinder cross-sectional direction at the edge part by the side of the process target fluid in the longitudinal direction of the outer cylinder 21 of the reaction tank 20. In addition, of the entire region in the longitudinal direction of the inner cylinder 22, a protruding portion 22 a that protrudes from the outer peripheral surface of the processing target is provided in a posture that extends over the entire periphery of the outer peripheral surface of the cylinder. Yes. The inner cylinder 22 inserted into the outer cylinder 21 is pressed against the discharge side wall of the outer cylinder 21 by the outlet coupling 18 so that the protruding portion 22a of the inner cylinder 22 is pressed toward the discharge side wall of the outer cylinder 21. Supported on the discharge side wall.

  A catalyst 25 is introduced into the inner cylinder 22. The catalyst 25 promotes oxidative decomposition of organic substances in the inner cylinder 22. As the catalyst 25, a catalyst containing at least one element of Ru, Pd, Rh, Pt, Au, Ir, Os, Fe, Cu, Zn, Ni, Co, Ce, Ti, Mn, and C is used. It is desirable.

Next, a characteristic configuration of the fluid purification device according to the embodiment will be described.
As shown in FIG. 3, the catalyst 25 is disposed only in a region in the vicinity of the downstream end of the entire region of the inner cylinder 22 in the fluid conveyance direction. This is for the reason explained below. That is, most organic substances contained in the wastewater are rapidly oxidatively decomposed without the aid of the catalyst 25. The promotion of oxidative decomposition by the catalyst 25 is necessary only for the hardly decomposable organic substances among the organic substances contained in the wastewater. Therefore, in the inner cylinder 22, the catalyst 25 is not intentionally disposed in the upstream end portion and the central portion in the fluid conveyance direction, and in those regions, the oxidation of organic matter that does not require the catalyst 25 is performed. The decomposition reaction is generated intensively. Then, the mixed fluid transported to the vicinity of the downstream end in the fluid transport direction of the inner cylinder 22 is in a state mainly containing only the hardly decomposable organic matter. By bringing the mixed fluid in this state into contact with the catalyst 25, the hardly decomposable organic matter is intensively oxidized and decomposed near the downstream end of the inner cylinder 22 in the fluid conveyance direction.

  In FIG. 1, the reaction tank 20 is provided with a first pressure gauge 29a and a second pressure gauge 29b. The first pressure gauge detects the pressure of the mixed fluid existing in the region in the vicinity of the upstream end of the entire region of the reaction tank 20 in the fluid conveyance direction. Further, the second pressure gauge detects the pressure of the mixed fluid existing in the region downstream of the catalyst 25 in the reaction tank 20 in the fluid conveyance direction.

  When deposits made of inorganic salts or the like adhere to and accumulate on the catalyst 25, the catalyst 25 becomes clogged. Then, in the inner cylinder 22, the pressure of the mixed fluid existing in the region upstream of the catalyst 25 becomes higher than the pressure of the mixed fluid existing in the region downstream of the catalyst 25. That is, the pressure detection result by the first pressure gauge 29a is higher than the pressure detection result by the second pressure gauge 29b. When such a pressure difference occurs, it is necessary to wash the catalyst 25 and wash away the deposits from the surface of the catalyst 25. Moreover, since it is considered that a large amount of deposits are also attached to the inner wall of the inner cylinder 22, it is desirable to clean the inner wall of the inner cylinder 22.

  Therefore, the programmable sequencer, when the pressure detection result by the first pressure gauge 29a is higher than the pressure detection result by the second pressure gauge 29b and the pressure difference exceeds a predetermined threshold value, A cleaning process for cleaning the inner wall of the inner cylinder 22 is performed. However, a pre-cleaning preparatory process is performed prior to this cleaning process.

  FIG. 6 is a flowchart showing each step in the pre-cleaning preparation process performed by the programmable sequencer. When the programmable sequencer starts the pre-cleaning preparation process, first, the raw water supply pump 3 and the pressure equalizing water pump 37 are stopped (steps 1 and 2; hereinafter, step is referred to as S), and then the oxidant pump 6 Is increased (S3). Thereby, if the pumping amount of air per unit time to the reaction tank 20 is increased, the humidity measuring valve 46 is opened (S4).

  At this time, the purified fluid still remains in the reaction tank 20. This purified fluid is discharged from the reaction tank (20), passes through the transfer pipe (16) and the outlet valve (13), and then enters the gas-liquid separator (45) to be depressurized and cooled. Separated into gas and liquid. After the elemental composition is analyzed by the gas ion chromatograph (48), the gas is released into the atmosphere. When the humidity measuring valve (46) is opened by the programmable sequencer, part of the gas separated by the gas-liquid separator (45) is released to the atmosphere after the humidity is detected by the hygrometer (47). It becomes like this. Immediately after the pre-cleaning preparatory process is started, the purified fluid is discharged from the reaction tank (20) and separated into gas and liquid by the gas-liquid separator 45, so the humidity of the gas after separation is compared. It is in a very high state.

  After a while, the pre-purification preparatory process is started, and most of the purified fluid in the inner cylinder (22) of the reaction tank (20) is exhausted from the inner cylinder (22) by the air, and the gas-liquid separator 45 Liquid separation. At this time, the inner wall of the inner cylinder (22) is still wet to some extent. For this reason, even if only the air is discharged without discharging the purified fluid from the inner cylinder (22), the humidity of the discharged air is relatively high for a while. Thereafter, when the inner wall of the inner cylinder (22) is dried, the dried air is discharged from the inner cylinder (22).

  When the humidity measurement valve (46) is opened (S4), the programmable sequencer waits until the humidity detected by the hygrometer falls below a predetermined threshold (N in S5). When the humidity detection result is equal to or greater than the predetermined threshold (Y in S5), the process waits until the element analysis result by the gas ion chromatograph (48) becomes substantially the same as the composition of the element in the atmosphere (in S6). N). When the analysis result of the element by the gas ion chromatograph (48) becomes substantially the same as the composition of the element in the atmosphere, this is the air pumped into the inner cylinder (22) by the oxidant pump (6). Means that the gas passes through the inner cylinder (22) as it is and is discharged from the gas-liquid separator (45).

  Therefore, the programmable sequencer stops the oxidant pump (6) when the element analysis result by the gas ion chromatograph (48) becomes almost the same as the composition of the element in the atmosphere (Y in S6) ( S7), a series of control flow ends.

  In FIG. 1, it is assumed that sulfuric acid, hydrochloric acid, nitric acid, etc. are generated along with the oxidative decomposition when the organic substance of the mixed fluid is oxidatively decomposed in the inner cylinder (22) in the reaction tank 20 during normal operation. However, since the inner wall of the inner cylinder (22) in contact with the acid is made of titanium that exhibits excellent corrosion resistance against the acid, it is possible to suppress the occurrence of damage to the inner cylinder (22) due to the acid. It is. Therefore, the occurrence of corrosion of the inner cylinder (22) when the organic matter of the mixed fluid is oxidatively decomposed in the inner cylinder (22) of the reaction tank 20 can be suppressed.

  Further, in the pre-cleaning preparatory process, the oxidant pump 6 and the programmable sequencer function as passive film regeneration means for regenerating the passive film by oxidizing the passive film loss location on the inner wall of the inner cylinder (22). . Specifically, the combination of the oxidant pump 6 and the programmable sequencer allows only the air to be pumped to the inner cylinder (22) so that only the air in the inner cylinder (22) is used as a titanium region. Oxygen is brought into contact with the entire region of the inner wall of the inner cylinder (22). As a result, even if a passive film loss location is generated in a partial region of the inner wall of the inner cylinder (22), oxygen is reliably brought into contact with the passive film loss location, and the passive membrane due to oxidation of titanium. Play. In this way, by regenerating the passive film at the place where the passive film is lost and ending the pre-cleaning preparation process, the inner cylinder (22) is subjected to the cleaning process in the inner cylinder (22). The occurrence of corrosion of the inner cylinder (22) due to the contact of the detergent containing sulfuric acid or hydrochloric acid with the passive film loss part of 22) can be suppressed.

  A step of turning on the preheating heater (23) may be added between S3 and S4. In this case, since the air is fed into the inner cylinder (22) while being heated by the preheating heater (23), the time until the inner wall of the inner cylinder (22) is completely dried can be shortened. it can.

  In addition, the example which employ | adopted the condition that the difference of the pressure detection result by the 1st pressure gauge 29a and the pressure detection result by the 2nd pressure gauge 29b exceeds a predetermined threshold as a trigger which starts the pre-cleaning preparation process was demonstrated. However, in the fluid purification device according to the embodiment, other conditions are also employed as a trigger. Specifically, a condition that the detection result by the TOC measuring device 49 exceeds a predetermined threshold and a condition that titanium is detected by the liquid ion chromatograph 50 are also employed as a trigger.

These triggers will be described in detail.
When the catalytic ability of the catalyst (25) is reduced due to the deposit, the oxidative decomposition of the hardly decomposable organic matter becomes incomplete, and a small amount of the hardly decomposable organic matter is oxidatively decomposed in the purified fluid. It will remain without. Then, the measurement result by the TOC measuring device 49 that measures the TOC (total organic carbon) of the purified liquid separated by the gas-liquid separator 45 exceeds a predetermined threshold value. In this case, since it is necessary to restore the catalytic ability of the catalyst (25) by washing the catalyst (25), a pre-purification preparatory process and a washing process described later are sequentially performed.

  Further, when waste water containing a large amount of organic matter is temporarily supplied into the inner cylinder (22) and a large amount of acid is temporarily generated in the inner cylinder (22), it is formed on the inner wall of the inner cylinder (22). A part of the passive film may be dissolved by acid. In this case, the liquid ion chromatograph 50 that performs elemental analysis of the purified liquid separated by the gas-liquid separator 45 detects a small amount of titanium.

  During operation, even if a portion of the passive film loss occurs on the inner wall of the inner cylinder (22) due to a large amount of acid, the oxygen in the oxidizing agent eventually comes into contact with the passive film loss portion, Will play naturally. However, the loss of the passive film occurs because a large amount of acid is generated. If left as it is, the loss of the passive film may be significantly corroded. Therefore, when the liquid ion chromatograph 50 detects a small amount of titanium, a pre-purification preparatory process is performed to quickly remove the acid generated in the inner cylinder (22). By discharging from the inside, damage to the inner cylinder (22) is effectively suppressed.

  FIG. 7 is a flowchart showing each step of the cleaning process performed by the programmable sequencer. This cleaning process is performed following the pre-purification preparation process. When the programmable sequencer starts the cleaning process, after closing the raw water tank valve (30) (S1) and opening the first fresh water tank valve (32) (S2), the programmable sequencer starts driving the raw water supply pump (3). (S3). Thereby, the fresh water as a cleaning agent is sent into the inner cylinder (22) of the reaction tank (20) by the raw water supply pump (3). Next, the preheating heater (33) is turned on (S4), and the cleaning effect is enhanced by sending the fresh water into the inner cylinder (22) while heating.

  Thereafter, the programmable sequencer waits until a predetermined time elapses (N in S5). When the predetermined time has elapsed (Y in S5), the preheating heater (23) and the raw water supply pump (3) are stopped (S6, 7), the raw water tank valve (30) is opened (S8), and After closing the first fresh water tank (31) (S9), a series of control flow is ended.

  In addition, although the example which uses fresh water as a cleaning agent was demonstrated, you may use the cleaning chemical | medical solution containing the chemical | medical agent for washing | cleaning as a cleaning agent.

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 an oxidative decomposition reaction of an organic substance in a mixed fluid while heating and pressurizing the mixed fluid obtained by mixing the fluid to be purified received inside itself and the oxidant to change it into a state different from the liquid. A reaction tank (for example, reaction tank 20) for generating water, a pre-purification fluid pumping means (for example, raw water supply pump 3) for pumping the fluid to be purified into the reaction tank, and an oxidant in the reaction tank. The pressure of the oxidant pressure feeding means (for example, the oxidant pressure feeding pump 6) for feeding pressure, the gas pressure feeding means (for example, the oxidant pressure feeding pump 6) for feeding a predetermined gas into the reaction tank, and the pressure of the fluid in the reaction tank. Pressure adjusting means (for example, outlet valve 13) to adjust, control means (for example, programmable sequencer) for controlling driving of the pre-purification fluid pressure feeding means, the oxidant pressure feeding means, the gas pressure feeding means, and the pressure adjusting means In the reaction tank, in the process of sending the mixed fluid from one end side to the other end side in the longitudinal direction of the reaction tank, the organic matter in the mixed fluid is oxidatively decomposed and purified by this oxidative decomposition. The fluid is discharged from the other end in the longitudinal direction of the reaction tank, and the control unit stops pumping the fluid to be processed by the pre-purification fluid pumping unit as a preparation before performing cleaning in the reaction tank. In this state, the gas is pumped to the reaction tank by the gas pumping means to make the fluid inside the reaction tank only the gas, and then the pressure of the gas in the reaction tank is lowered by the pressure adjusting means. In the fluid purification apparatus for performing pre-cleaning preparatory processing, the region in contact with the mixed fluid in the reaction tank is made of titanium, and in the pre-cleaning pre-processing, the surface of titanium in the reaction tank Kicking is characterized in the provision of the passivation film reproducing means for reproducing the passivation film of the passivation film loss location (e.g. oxidizing agent feed pump and a programmable sequencer).

[Aspect B]
Aspect B is Aspect A, wherein the oxidant pumping means pumps an oxygen-containing gas (for example, air) containing oxygen as the oxidant, and also functions as the gas pumping means. The control means increases the oxygen-containing gas pumping speed by the oxidant pumping means in the pre-cleaning preparatory process so that the fluid inside the reaction vessel is only the oxygen-containing gas, The combination of the oxidant pumping means and the control means has a function as the passive film regeneration means for regenerating the passive film at the location where the passive film is lost on the titanium surface of the reaction tank by pumping the oxygen-containing gas. It is also used for both purposes. In such a configuration, without providing a dedicated passive film regeneration means for performing the regeneration treatment of the passive film on the titanium surface of the reaction tank, the combination of the oxidant pumping means and the control means allows the passivation film to be formed. Reproduction can reduce costs.

[Aspect C]
Aspect C is that in aspect A or B, a catalyst (for example, catalyst 25) that promotes oxidative decomposition of organic matter is disposed at the downstream end in the fluid transport direction of the reaction tank, and the upstream in the fluid transport direction of the reaction tank. Pressure difference detecting means for detecting the pressure difference of the mixed fluid between the side end and the downstream end is provided, and the pre-cleaning preparatory process is performed based on the fact that the pressure difference exceeds a predetermined threshold value. As described above, the control means is configured. In such a configuration, based on the detection result of the pressure difference by the pressure difference detection means exceeding a predetermined threshold, clogging of the fluid conveyance path in the reaction tank due to the adhesion of the precipitate is detected, and the pre-purification preparatory process is automatically performed. Can be implemented.

[Aspect D]
Aspect D is provided with titanium detection means (for example, liquid ion chromatograph 50) for detecting titanium from the purified fluid discharged from the reaction tank in any one of aspects A to C, and titanium is detected by the titanium detection means. The control means is configured to start the pre-cleaning preparatory process based on the fact that the detection is detected. In such a configuration, it is detected that a large amount of acid has been generated in the reaction tank based on the detection of titanium by the titanium detection means, and the passive film is actively regenerated by performing pre-purification preparatory processing. be able to.

3: Raw water supply pump (fluid pre-purification means)
6: Oxidant pump (oxidant pumping means, gas pumping means, immobile membrane regeneration means)
13: Outlet valve (pressure adjusting means)
20: Reaction tank 25: Catalyst 50: Ion chromatograph for liquid (titanium detection means)

JP 2001-9482 A

Claims (1)

In order to generate an oxidative decomposition reaction of organic matter in the mixed fluid while heating and pressurizing the mixed fluid obtained by mixing the fluid to be purified and the oxidant received inside and changing it to a state different from the liquid Reaction tank, pre-purification fluid pumping means for pumping the fluid to be purified into the reaction tank, oxidant pumping means for pumping an oxidant into the reaction tank, and a predetermined gas in the reaction tank Gas pressure feeding means for pressure feeding, pressure adjusting means for adjusting the pressure of the fluid in the reaction tank, the pre-purification fluid pressure feeding means, the oxidant pressure feeding means, the gas pressure feeding means, and driving of the pressure regulation means. Control means for controlling, and in the process of sending the mixed fluid in the reaction tank from one end side to the other end side in the longitudinal direction of the reaction tank, the organic matter in the mixed fluid is oxidatively decomposed, and this oxidative decomposition Purified fluid purified by Discharging from the other end of the reaction tank in the longitudinal direction, and the control means stopped the pumping of the fluid to be treated by the pre-purification fluid pumping means as a preparation before carrying out the cleaning of the reaction tank. In this state, after the gas is pumped to the reaction tank by the gas pumping means to make the fluid inside the reaction tank only the gas, the pressure adjusting means is used to lower the pressure of the gas in the reaction tank. In the fluid purification device that performs the pre-treatment,
The region in contact with the mixed fluid in the reaction tank is made of titanium,
A fluid purification apparatus comprising a passive film regeneration means for regenerating the passive film at a location where the passive film is lost on the titanium surface of the reaction tank in the pre-cleaning preparation process .

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