JP2012055831A - Method for treating waste liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating waste liquid capable of suppressing deterioration of a decomposition rate of an organic substance, generation of NOx and damage of a reactor without adjusting the concentration of the organic substance in waste liquid.SOLUTION: A waste liquid treating device 100 includes: the reactor 10 for changing water to subcritical water, superheated steam or supercritical water; a container 21 for storing the waste liquid 21a; a waste liquid supplying section 20; a hydrogen peroxide solution supplying section 30; a heater 50; a gas-liquid separation section 70; a total organic carbon measuring meter Cfor detecting the concentration of the organic substance in the waste liquid; a reactor inside temperature detecting sensor T; an ion meter Cfor detecting the concentration of a liquid component; and a gas concentration detector Cfor detecting the concentration of a gas component. The device also includes steps of: setting waste liquid supply speed and hydrogen peroxide solution supply speed based on the concentration of the organic substance detected by the total organic carbon measuring meter; and resetting the waste liquid supply speed and hydrogen peroxide solution supply speed based on the reactor inside temperature, the concentration of the component detected by the ion meter and the concentration of the gas component detected by the gas concentration detector.

Description

  The present invention relates to a waste liquid treatment method.

  Conventionally, methods such as incineration and biological treatment are known as methods for treating waste liquid. However, the incineration process has a problem that energy and chemicals are required in the pretreatment dehydration and solid content aggregation, and dioxins are generated due to incomplete combustion. In addition, the biological treatment has a problem that the treatment time is long and the activated sludge generated after the treatment becomes a new waste.

  Therefore, a method for treating a waste liquid in hot water such as subcritical water, superheated steam, or supercritical water is known.

  Patent Document 1 discloses a concentration adjustment tank that is supplied with liquid organic waste and water to adjust the liquid organic waste to a predetermined concentration, and the liquid organic waste having a predetermined concentration is subjected to pressure under a desired subcritical condition. Disclosed is a wet oxidative decomposition treatment apparatus comprising a high-pressure pump that pressurizes and continuously supplies liquid organic waste of a predetermined concentration to a oxidative decomposition treatment furnace, and a wet oxidative decomposition treatment furnace that performs wet oxidative decomposition treatment in a subcritical state. It has been. At this time, the prescribed concentration is set to a temperature at which the temperature in the oxidative decomposition treatment furnace by the heat of reaction of oxidative decomposition becomes the temperature of the desired subcritical condition.

  However, unless the liquid organic waste is adjusted to a predetermined concentration, there are problems that the decomposition rate of the liquid organic waste is reduced, NOx is generated, and the oxidative decomposition treatment furnace is damaged.

  In view of the above-described problems of the prior art, the present invention is a waste liquid treatment capable of suppressing a decrease in the decomposition rate of organic substances, generation of NOx, and damage to a reactor without adjusting the concentration of organic substances in the waste liquid. It aims to provide a method.

  The invention according to claim 1 is a method for treating a waste liquid containing water and organic matter using a waste liquid treatment apparatus, wherein the waste liquid treatment apparatus converts the water into subcritical water, superheated steam or supercritical water. A reactor for oxidizing the organic matter, a container for storing the waste liquid, a waste liquid supply means for supplying the waste liquid from the container to the reactor, and an oxidant supply for supplying an oxidant to the reactor Means, heating means for heating the reactor, gas-liquid separation means for gas-liquid separation of the waste liquid oxidized from the organic matter discharged from the reactor into a liquid component and a gas component, and stored in the container A first detecting means for detecting the concentration of the organic substance in the waste liquid; a second detecting means for detecting the temperature inside the reactor; and a third for detecting the concentration of the component contained in the liquid component. Detecting means, and the gas component A supply speed at which the waste liquid is supplied by the waste liquid supply means based on the concentration of the organic substance detected by the first detection means; And a step of setting a supply rate at which the oxidant is supplied by the oxidant supply unit, a temperature inside the reactor at the supply rate detected by the second detection unit, and a third detection unit Supply of the waste liquid based on the concentration of the component contained in the liquid component at the supply speed detected by the method and the concentration of the component contained in the gas component at the supply speed detected by the fourth detection means. And a step of resetting the speed at which the waste liquid is supplied by the means and the speed at which the oxidant is supplied by the oxidant supply means.

  According to a second aspect of the present invention, in the waste liquid treatment method according to the first aspect, the third detection unit detects the concentrations of NOx and ammonia in the liquid component, and the fourth detection unit includes: The concentration of oxygen, carbon dioxide, carbon monoxide, NOx, SOx, ammonia and hydrogen sulfide in the gas component is detected.

  According to a third aspect of the present invention, in the waste liquid treatment method according to the first or second aspect, the waste liquid treatment apparatus includes a plurality of containers that store the waste liquid.

  ADVANTAGE OF THE INVENTION According to this invention, even if it does not adjust the density | concentration of the organic substance in a waste liquid, the waste liquid processing method which can suppress the fall of the decomposition | disassembly rate of an organic substance, generation | occurrence | production of NOx, and damage to a reactor can be provided. .

It is a figure which shows an example of the waste-liquid processing apparatus used by this invention.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows an example of the waste liquid treatment apparatus of the present invention. The waste liquid treatment apparatus 100 for treating the waste liquid 21a containing water and organic matter changes the water into subcritical water, superheated steam or supercritical water, and supplies the waste liquid 21a to the reactor 10 for oxidizing the organic matter. A waste liquid supply unit 20 that supplies the hydrogen peroxide solution 31a to the reactor 10, and a preheater 40 that preheats the waste liquid 21a and the hydrogen peroxide solution 31a that are supplied to the reactor 10. The heater 50 for heating the reactor 10, the heat exchanger 60 for exchanging heat with the waste liquid in which the organic matter discharged from the reactor 10 is oxidized, and the waste liquid in which the organic matter discharged from the reactor 10 is oxidized are gas-liquid separated. A gas-liquid separator 70 is provided.

The reactor 10 is filled with MnO ₂ (not shown) as an oxidation catalyst in the vicinity of the end on the side where the waste liquid in which the organic matter is oxidized is discharged.

In place of MnO ₂ , Pt, Ir, Ag, Pd, Rh, Ru, Cu, Ni, Co, Fe, W, PdO, PtO, PtO ₂ , Ag ₂ O, RuO ₂ , CuO, Co ₃ O ₄ NiO, Fe ₂ O ₃ , V ₂ O 5, Cr ₂ O ₃ , CdO, CeO ₂ , Al ₂ O ₃ , ThO _2, or the like may be used.

  The temperature inside the reactor 10 is detected by a temperature sensor T as a second detection means, and the heater 50 is controlled so as to reach a predetermined temperature.

  Although it does not specifically limit as the heater 50, A rubber heater, a band heater, etc. are mentioned.

The waste liquid supply unit 20 includes a tank 21 in which the waste liquid 21 a is stored, a slurry pump 22 that compresses the waste liquid 21 a and continuously supplies the waste liquid 21 a to the reactor 10, and an on-off valve 23. At this time, the stirring blade 21b is installed in the tank 21, and the waste liquid 21a can be stirred. The pressure of the waste liquid 21a to be supplied to the reactor 10 is detected by the pressure sensor P _1, slurry pump 22 is controlled to a predetermined pressure.

  The pressure of the waste liquid 21a supplied to the reactor 10 is usually 1 to 50 MPa, and preferably 5 to 35 MPa.

The hydrogen peroxide solution supply unit 30 compresses the hydrogen peroxide solution 31a to a pressure higher than the pressure at which the waste liquid is supplied and continuously supplies the hydrogen peroxide solution 31a from the tank 31 to the reactor 10. A syringe pump 32 and an opening / closing valve 33 are provided. At this time, the pressure of the hydrogen peroxide 31a fed to the reactor 10 is detected by the pressure sensor P _2, the syringe pump 32 is controlled to a predetermined pressure.

The concentration of organic matter in the waste liquid 21a that is stored in the tank 21, as the first detecting means is detected by total organic carbon measuring device C _1.

At this time, based on the concentration of total organic carbon in the effluent 21a which is stored in tank 21 detected by the total organic carbon measuring device C _1, the reactor 10 effluent 21a pressure and reactor 10 is supplied to the The pressure of the hydrogen peroxide solution 31a to be supplied is set.

  At this time, the preheater 40 may decompose the hydrogen peroxide contained in the hydrogen peroxide solution 31a to generate oxygen.

As described above, in the reactor 10, the waste liquid 21a supplied from the waste liquid supply unit 20 and the hydrogen peroxide solution 31a introduced from the hydrogen peroxide solution supply unit 30 are mixed. At this time, the waste liquid 21a and the hydrogen peroxide solution 31a are preheated by the preheater 40. Next, the water contained in the waste liquid 21a and the hydrogen peroxide solution 31a is changed to subcritical water, superheated steam or supercritical water, and the organic matter contained in the waste liquid 21a is oxidized and reduced. It is molecularized. Furthermore, the organic substance reduced in molecular weight is completely oxidized by the catalytic action of MnO ₂ .

  Since water (not shown) is stored in the heat exchanger 60, steam is generated by exchanging heat with water from the waste liquid in which the organic matter discharged from the reactor 10 is oxidized.

  The gas-liquid separation unit 70 includes a back pressure valve 71 that depressurizes the waste liquid that has been oxidized by the organic matter discharged from the heat exchanger 60 to atmospheric pressure, and a gas-liquid separator 72 that gas-liquid separates the waste liquid that has been oxidized by the reduced organic matter. Have. At this time, the gas-liquid separator 72 separates the waste liquid obtained by oxidizing the reduced-pressure organic matter into water components containing a slight amount of inorganic acid or the like as a liquid component and gas components containing carbon dioxide gas, nitrogen gas, or the like, The liquid component is recovered. The liquid component is reused as industrial water after confirming the water quality standard.

The concentration of NOx and ammonia in the liquid component, as a third means of detection are detected by an ion meter C _2. Further, oxygen in the gaseous component, carbon dioxide, carbon monoxide, NOx, SOx, the concentration of ammonia and hydrogen sulfide, as a fourth means of detection is detected by the gas concentration detector C _3.

At this time, the inside of the reactor 10 detected by the temperature sensor T temperature, NOx and ammonia in the liquid component, which is detected by the ion meter C ₂ concentration and in the gas component detected by the gas concentration detector C ₃ Based on the concentrations of oxygen, carbon dioxide, carbon monoxide, NOx and ammonia, the pressure of the waste liquid 21a supplied to the reactor 10 and the pressure of the hydrogen peroxide solution 31a supplied to the reactor 10 are reset. For this reason, it is possible to optimize the ratio of hydrogen peroxide contained in the hydrogen peroxide solution 31a supplied to the reactor 10 with respect to the organic matter contained in the waste liquid 21a supplied to the reactor 10. As a result, it is possible to suppress the degradation of the organic matter due to the lack of hydrogen peroxide and the generation of NOx due to the excessive presence of hydrogen peroxide. Moreover, the total amount of the organic substance contained in the waste liquid 21a supplied to the reactor 10 and the hydrogen peroxide contained in the hydrogen peroxide solution 31a can be optimized. As a result, it is possible to suppress a decrease in the decomposition rate of organic substances due to a decrease in the temperature inside the reactor 10 and damage to the reactor 10 due to an increase in the temperature inside the reactor 10.

  The ratio of hydrogen peroxide contained in the hydrogen peroxide solution 31a supplied to the reactor 10 to hydrogen peroxide required to oxidize organic substances contained in the waste liquid 21a supplied to the reactor 10 is usually 1 to 1. 5, preferably 1 to 1.5.

  The temperature inside the reactor 10 is usually 100 to 700 ° C, preferably 200 to 600 ° C.

The third detection means is a component containing H, B, C, N, O, F, Si, P, S, Cl, Ge, As, Se, Br, Te, I, At contained in the liquid component. if it is possible to detect the concentration, but is not limited to ion meter C _2.

As a fourth detection means, a component containing H, B, C, N, O, F, Si, P, S, Cl, Ge, As, Se, Br, Te, I, At contained in the gas component if it is possible to detect the concentration, but is not limited to the gas concentration detector C _3.

  Instead of the hydrogen peroxide solution supply unit 30 for supplying the hydrogen peroxide solution 31a to the reactor 10, an air supply unit for supplying air to the reactor 10, an ozone supply unit for supplying ozone to the reactor 10, etc. It may be used.

  Further, the waste liquid supply unit 20 may have a plurality of tanks 21. Thereby, while processing the waste liquid 21a stored in one tank 21, the concentration of the organic matter in the waste liquid 21a stored in the other tank 21 can be detected.

  Hereinafter, the present invention will be specifically described based on examples.

[Example 1]
Using the waste liquid treatment apparatus 100, an aqueous methanol solution having an unknown concentration was treated. At this time, the reactor 10 was made of SUS316, and 5 g of MnO ₂ was charged in the vicinity of the end portion on the side where the waste liquid oxidized with methanol was discharged.

  First, with the on-off valves 23 and 32 closed, the reactor 10 was heated using a heater 50 until the internal temperature reached 400 ° C. At this time, the temperature inside the preheater 40 is 400 ° C., and the hydrogen peroxide contained in the hydrogen peroxide solution 31a is decomposed to generate oxygen.

Next, the on-off valves 23 and 32 are opened, the aqueous methanol solution is supplied to the reactor 10 at 10 MPa using the slurry pump 22, and the 30 mass% hydrogen peroxide solution 31 a is supplied at 10 MPa using the syringe pump 32. Reactor 10 was fed. At this time, the concentration of total organic carbon in the effluent 21a which is stored in tank 21 detected by the total organic carbon measuring device C ₁ is because it was 37484mg / L, peroxide aqueous solution of methanol fed to the reactor 10 The flow rate ratio of the hydrogen water 31a was set to 1.27, and the total flow rate of the aqueous methanol solution and the hydrogen peroxide solution 31a was set to 0.4 mL / min. The residence time of the aqueous methanol solution and the hydrogen peroxide solution 31a in the reactor 10 was 1 minute.

  Next, the waste liquid in which the methanol discharged from the reactor 10 was oxidized was instantaneously cooled to 25 ° C. by exchanging heat with water stored in the heat exchanger 60. Further, the waste liquid in which the cooled methanol was oxidized was decompressed by the back pressure valve 71 and then separated into a liquid component and a gas component by the gas-liquid separator 72.

As a result, the temperature inside the reactor 10 was 412 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is a 1.32 times of oxygen consumed in the oxidation of methanol Yes, the decomposition rate of methanol was 96% based on the total organic carbon. Furthermore, the concentration of NOx in the liquid component detected by the ion meter _{C 2} is at 30ppm or more, the concentration of NOx in the gas component detected by the gas concentration detector _{C 3} were 5ppm or higher.

  Next, an aqueous methanol solution was supplied to the reactor 10 at 10 MPa using the slurry pump 22, and a 30 mass% hydrogen peroxide solution 31 a was supplied to the reactor 10 at 10 MPa using the syringe pump 32. At this time, the aqueous methanol solution supplied to the reactor 10 so that the temperature inside the reactor 10 is 430 ° C. and the oxygen supplied to the reactor 10 is 1.2 times the oxygen consumed for the oxidation of methanol. The flow rate ratio of the hydrogen peroxide solution 31a to 1.15 was reset, and the total flow rate of the methanol aqueous solution and the hydrogen peroxide solution 31a was reset to 1 mL / min. The residence time of the aqueous methanol solution and the hydrogen peroxide solution 31a in the reactor 10 was 1 minute.

As a result, the temperature inside the reactor 10 was 430 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is 1.2 times the oxygen consumed in the oxidation of methanol Yes, the decomposition rate of methanol was 99.9% based on the total organic carbon. Furthermore, the concentration of NOx and ammonia in the liquid component detected by the ion meter C ₂ are both less than 30 ppm, the carbon monoxide in the gas component detected by the gas concentration detector C _3, the NOx and ammonia The concentrations were all less than 5 ppm.

[Example 2]
Using the waste liquid treatment apparatus 100, the aqueous methanol solution of Example 1 was treated. At this time, the reactor 10 was made of SUS316, and 5 g of MnO ₂ was charged in the vicinity of the end portion on the side where the waste liquid oxidized with methanol was discharged.

  First, with the on-off valves 23 and 32 closed, the reactor 10 was heated using a heater 50 until the internal temperature reached 350 ° C. At this time, the temperature inside the preheater 40 is 350 ° C., and the hydrogen peroxide contained in the hydrogen peroxide solution 31a is decomposed to generate oxygen.

Next, the on-off valves 23 and 32 are opened, the aqueous methanol solution is supplied to the reactor 10 at 10 MPa using the slurry pump 22, and the 30 mass% hydrogen peroxide solution 31 a is supplied at 10 MPa using the syringe pump 32. Reactor 10 was fed. At this time, the concentration of total organic carbon in the effluent 21a which is stored in tank 21 detected by the total organic carbon measuring device C ₁ is because it was 37484mg / L, peroxide aqueous solution of methanol fed to the reactor 10 The flow rate ratio of the hydrogen water 31a was set to 1.27, and the total flow rate of the aqueous methanol solution and the hydrogen peroxide solution 31a was set to 0.4 mL / min. The residence time of the aqueous methanol solution and the hydrogen peroxide solution 31a in the reactor 10 was 1 minute.

  Next, the waste liquid in which the methanol discharged from the reactor 10 was oxidized was instantaneously cooled to 25 ° C. by exchanging heat with water stored in the heat exchanger 60. Further, the waste liquid in which the cooled methanol was oxidized was decompressed by the back pressure valve 71 and then separated into a liquid component and a gas component by the gas-liquid separator 72.

As a result, the temperature inside the reactor 10 was 361 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is a 1.35 times of the oxygen consumed in the oxidation of methanol Yes, the decomposition rate of methanol was 80% based on the total organic carbon. Furthermore, the concentration of NOx in the liquid component detected by the ion meter _{C 2} is at 30ppm or more, the concentration of NOx in the gas component detected by the gas concentration detector _{C 3} were 5ppm or higher.

  Next, an aqueous methanol solution was supplied to the reactor 10 at 10 MPa using the slurry pump 22, and a 30 mass% hydrogen peroxide solution 31 a was supplied to the reactor 10 at 10 MPa using the syringe pump 32. At this time, the aqueous methanol solution supplied to the reactor 10 so that the temperature inside the reactor 10 is 430 ° C. and the oxygen supplied to the reactor 10 is 1.2 times the oxygen consumed for the oxidation of methanol. The flow rate ratio of the hydrogen peroxide solution 31a to 1.15 was reset, and the total flow rate of the methanol aqueous solution and the hydrogen peroxide solution 31a was reset to 2.7 mL / min. The residence time of the aqueous methanol solution and the hydrogen peroxide solution 31a in the reactor 10 was 1 minute.

As a result, the temperature inside the reactor 10 was 431 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is 1.2 times the oxygen consumed in the oxidation of methanol Yes, the decomposition rate of methanol was 99.9% based on the total organic carbon. Furthermore, the concentration of NOx and ammonia in the liquid component detected by the ion meter C ₂ are both less than 30 ppm, the carbon monoxide in the gas component detected by the gas concentration detector C _3, the NOx and ammonia The concentrations were all less than 5 ppm.

[Example 3]
Using the waste liquid treatment apparatus 100, an aqueous methanol solution having an unknown concentration was treated. At this time, the reactor 10 was made of SUS316, and 5 g of MnO ₂ was charged in the vicinity of the end portion on the side where the waste liquid oxidized with methanol was discharged.

  First, with the on-off valves 23 and 32 closed, the reactor 10 was heated using a heater 50 until the internal temperature reached 400 ° C. At this time, the temperature inside the preheater 40 is 400 ° C., and the hydrogen peroxide contained in the hydrogen peroxide solution 31a is decomposed to generate oxygen.

Next, the on-off valves 23 and 32 are opened, the aqueous methanol solution is supplied to the reactor 10 at 10 MPa using the slurry pump 22, and the 30 mass% hydrogen peroxide solution 31 a is supplied at 10 MPa using the syringe pump 32. Reactor 10 was fed. At this time, the concentration of total organic carbon in the effluent 21a which is stored in tank 21 detected by the total organic carbon measuring device C ₁ is because it was 18742mg / L, peroxide aqueous solution of methanol fed to the reactor 10 The flow rate ratio of the hydrogen water 31a was set to 0.635, and the total flow rate of the aqueous methanol solution and the hydrogen peroxide solution 31a was set to 0.4 mL / min. The residence time of the aqueous methanol solution and the hydrogen peroxide solution 31a in the reactor 10 was 1 minute.

  Next, the waste liquid in which the methanol discharged from the reactor 10 was oxidized was instantaneously cooled to 25 ° C. by exchanging heat with water stored in the heat exchanger 60. Further, the waste liquid in which the cooled methanol was oxidized was decompressed by the back pressure valve 71 and then separated into a liquid component and a gas component by the gas-liquid separator 72.

As a result, the temperature inside the reactor 10 was 407 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, oxygen supplied to the reactor 10 is consumed for the oxidation of methanol, the decomposition of methanol Was 81% based on the total organic carbon. Further, the concentration of ammonia in the liquid component detected by the ion meter C ₂ is 30 ppm or more, and the concentrations of carbon monoxide and ammonia in the gas component detected by the gas concentration detector C ₃ are both 5 ppm or more. Met.

  Next, an aqueous methanol solution was supplied to the reactor 10 at 10 MPa using the slurry pump 22, and a 30 mass% hydrogen peroxide solution 31 a was supplied to the reactor 10 at 10 MPa using the syringe pump 32. At this time, the aqueous methanol solution supplied to the reactor 10 so that the temperature inside the reactor 10 is 430 ° C. and the oxygen supplied to the reactor 10 is 1.2 times the oxygen consumed for the oxidation of methanol. The flow rate ratio of the hydrogen peroxide solution 31a to 0.92 was reset to 0.92, and the total flow rate of the methanol aqueous solution and the hydrogen peroxide solution 31a was reset to 1.1 mL / min. The residence time of the aqueous methanol solution and the hydrogen peroxide solution 31a in the reactor 10 was 1 minute.

As a result, the temperature inside the reactor 10 was 430 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is a 1.15 times of the oxygen consumed in the oxidation of methanol Yes, the decomposition rate of methanol was 99.9% based on the total organic carbon. Furthermore, the concentration of NOx and ammonia in the liquid component detected by the ion meter C ₂ are both less than 30 ppm, the carbon monoxide in the gas component detected by the gas concentration detector C _3, the NOx and ammonia The concentrations were all less than 5 ppm.

[Comparative Example 1]
Using the waste liquid treatment apparatus 100, the aqueous methanol solution of Example 1 was treated. At this time, the reactor 10 was made of SUS316, and 5 g of MnO ₂ was charged in the vicinity of the end portion on the side where the waste liquid oxidized with methanol was discharged.

  First, with the on-off valves 23 and 32 closed, the reactor 10 was heated using a heater 50 until the internal temperature reached 400 ° C. At this time, the temperature inside the preheater 40 is 400 ° C., and the hydrogen peroxide contained in the hydrogen peroxide solution 31a is decomposed to generate oxygen.

  Next, the on-off valves 23 and 32 are opened, the aqueous methanol solution is supplied to the reactor 10 at 10 MPa using the slurry pump 22, and the 30 mass% hydrogen peroxide solution 31 a is supplied at 10 MPa using the syringe pump 32. Reactor 10 was fed. At this time, the flow rate ratio of the hydrogen peroxide solution 31a to the methanol aqueous solution supplied to the reactor 10 was set to 0.5, and the total flow rate of the methanol aqueous solution and the hydrogen peroxide solution 31a was set to 1 mL / min. The residence time of the aqueous methanol solution and the hydrogen peroxide solution 31a in the reactor 10 was 1 minute.

  Next, the waste liquid in which the methanol discharged from the reactor 10 was oxidized was instantaneously cooled to 25 ° C. by exchanging heat with water stored in the heat exchanger 60. Further, the waste liquid in which the cooled methanol was oxidized was decompressed by the back pressure valve 71 and then separated into a liquid component and a gas component by the gas-liquid separator 72.

As a result, the temperature inside the reactor 10 was 413 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, oxygen supplied to the reactor 10 is consumed for the oxidation of methanol, the decomposition of methanol Was 47% based on the total organic carbon. Further, the concentration of ammonia in the liquid component detected by the ion meter C ₂ is 30 ppm or more, and the concentrations of carbon monoxide and ammonia in the gas component detected by the gas concentration detector C ₃ are both 5 ppm or more. Met.

[Comparative Example 2]
The aqueous methanol solution was treated in the same manner as in Comparative Example 1 except that the flow rate ratio of the hydrogen peroxide solution 31a to the aqueous methanol solution supplied to the reactor 10 was set to 2.

As a result, the temperature inside the reactor 10 was 414 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is twice the oxygen consumed in the oxidation of methanol, The decomposition rate of methanol was 99% based on the total organic carbon. Furthermore, the concentration of NOx in the liquid component detected by the ion meter _{C 2} is at 30ppm or more, the concentration of NOx in the gas component detected by the gas concentration detector _{C 3} were 5ppm or higher.

[Comparative Example 3]
Comparative Example 1 except that the flow rate ratio of the hydrogen peroxide solution 31a to the methanol aqueous solution supplied to the reactor 10 was set to 1.15, and the total flow rate of the methanol aqueous solution and the hydrogen peroxide solution 31a was set to 0.1 mL / min. Similarly, a methanol aqueous solution was treated.

As a result, the temperature inside the reactor 10 was 403 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is 1.2 times the oxygen consumed in the oxidation of methanol Yes, the decomposition rate of methanol was 85% based on the total organic carbon. Further, the concentration of ammonia in the liquid component detected by the ion meter C ₂ is 30 ppm or more, and the concentrations of carbon monoxide and ammonia in the gas component detected by the gas concentration detector C ₃ are both 5 ppm or more. Met.

[Comparative Example 4]
The aqueous methanol solution was treated in the same manner as in Comparative Example 3 except that the total flow rate of the aqueous methanol solution and the hydrogen peroxide solution 31a supplied to the reactor 10 was set to 3.5 mL / min.

As a result, the temperature inside the reactor 10 was 505 ° C. Further, the concentration of carbon dioxide and carbon monoxide in the gas component detected by the gas concentration detector C _3, supplied oxygen to the reactor 10 is 1.2 times the oxygen consumed in the oxidation of methanol Yes, the decomposition rate of methanol was 99.9% based on the total organic carbon. Furthermore, the concentration of NOx and ammonia in the liquid component detected by the ion meter C ₂ are both less than 30 ppm, the carbon monoxide in the gas component detected by the gas concentration detector C _3, the NOx and ammonia The concentrations were all less than 5 ppm.

  In addition, since the reactor 10 is made of SUS316, there is a risk of damage if the internal temperature exceeds 450 ° C.

DESCRIPTION OF SYMBOLS 100 Waste liquid processing apparatus 10 Reactor 20 Waste liquid supply part 21 Tank 21a Waste liquid 21b Stirring blade 22 Slurry pump 23 Open / close valve 30 Hydrogen peroxide solution supply part 31 Tank 31a Hydrogen peroxide water 32 Syringe pump 33 Open / close valve 40 Preheater 50 Heater 60 Heat exchanger 70 Gas-liquid separator 71 Back pressure valve 72 Gas-liquid separator T Temperature sensor P ₁ , P ₂ Pressure sensor C ₁ Total organic carbon measuring device C ₂ Ion meter C ₃ Gas concentration detector

JP 2006-239539 A

Claims (3)

A method of treating waste liquid containing water and organic matter using a waste liquid treatment apparatus,
The waste liquid treatment apparatus converts the water into subcritical water, superheated steam or supercritical water and oxidizes the organic matter, a container for storing the waste liquid, and the waste liquid from the container to the reactor. A waste liquid supply means for supplying the reactor, an oxidant supply means for supplying an oxidant to the reactor, a heating means for heating the reactor, and a waste liquid obtained by oxidizing the organic matter discharged from the reactor as a liquid component. A gas-liquid separating means for separating the liquid into gas components; a first detecting means for detecting the concentration of the organic substance in the waste liquid stored in the container; and a second for detecting the temperature inside the reactor. Detection means, third detection means for detecting the concentration of the component contained in the liquid component, and fourth detection means for detecting the concentration of the component contained in the gas component,
Based on the concentration of the organic substance detected by the first detection means, a supply speed at which the waste liquid is supplied by the waste liquid supply means and a supply speed at which the oxidant is supplied by the oxidant supply means are set. Process,
The temperature inside the reactor at the supply speed detected by the second detection means, the concentration of the component contained in the liquid component at the supply speed detected by the third detection means, and the fourth Based on the concentration of the component contained in the gas component at the supply speed detected by the detection means, the oxidant is supplied by the speed at which the waste liquid is supplied by the waste liquid supply means and the oxidant supply means. A waste liquid treatment method comprising a step of resetting the speed of the waste liquid. The third detection means detects the concentration of NOx and ammonia in the liquid component,
The waste liquid treatment method according to claim 1, wherein the fourth detection means detects concentrations of oxygen, carbon dioxide, carbon monoxide, NOx, SOx, ammonia, and hydrogen sulfide in the gas component.   The waste liquid treatment method according to claim 1, wherein the waste liquid treatment apparatus includes a plurality of containers that store the waste liquid.

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