KR100249496B1 - Process for oxidizing liquid wastes containing organic compounds using supercritical water and catalytic oxidation - Google Patents

Abstract

The present invention relates to a high efficiency wastewater treatment process suitable for the treatment of wastewater, sewage sludge and organic wastewater containing high concentration, hardly decomposable or toxic organic matter which is difficult to be treated by biological treatment, and more particularly, organic matter using supercritical water oxidation. In the oxidative decomposition process of the waste liquid, the supercritical state of water having an internal pressure of at least 218 atm and an internal temperature of at least 374 ° C, an upper region with at least two thermostats and an internal pressure of at least 218 atm and an internal temperature of A subcritical state of water below 374 ° C., cooled by the incoming waste liquid, and at the same time, the introduced waste liquid is attached to a reactor cooler which is heated by the heat of the reactor lower region, and the reactor includes a lower region including a catalytic reaction layer. Providing; Introducing a waste liquid containing organic material into the top of the reactor at a temperature of at least 374 ° C. and at least 218 atmospheres and at an oxidant at a temperature of at least 20 ° C. and at least 218 atmospheres; And the treated water from which the organic material is oxidatively decomposed into a subcritical state of water having a temperature of less than 374 ° C. and a pressure of 218 atm or higher to the outside of the reactor through a discharge pipe from the lower part of the reactor. The oxidative decomposition process of a waste liquid containing.

Description

Oxidative Decomposition of Wastewater Containing Organics Using Supercritical Water and Catalytic Oxidation

The present invention relates to a process for oxidatively decomposing organic matter-containing waste liquid by using supercritical water oxidation and catalytic oxidation, and more particularly, to react organic matter contained in waste liquid by reacting the waste liquid containing organic matter under high temperature and high pressure. It relates to a step of oxidizing and removing. In particular, the present invention is suitable for the treatment of wastewater, sewage sludge and organic waste liquids containing high concentrations, hardly decomposable or toxic organic substances which are difficult to be treated by biological treatment, and oxidize organic substances at temperatures and pressures above the critical point of the water to produce harmless components. The present invention relates to a supercritical water oxidation treatment process to be treated and a high efficiency waste liquid treatment process using a catalytic oxidation method to promote the oxidation reaction of organic matter.

Representative by-products generated by industrialization include industrial wastewater and wastewater discharged from various industrial sites. Currently, the most widely used method of treating industrial wastewater and waste liquor is a biological treatment method, but is not suitable for the treatment of waste water and waste liquor containing a high concentration of organic matter, or particularly containing hardly degradable organic matter or toxic organic matter. In order to solve this problem, the development of many technologies is a wastewater treatment technology by supercritical water oxidation method. Supercritical water oxidation is a method of adjusting the water itself in which contaminants exist above a critical point of water (temperature 374 ° C., pressure 218 atm) and oxidizing contaminants in the presence of an oxygen source such as oxygen or air. In supercritical water, oxidation can decompose more than 99.99% of most organic contaminants within minutes. In this case, the main product is water vapor, carbon dioxide, etc., and the final aqueous solution mixture is harmless, so it can be discharged as it is without special aftertreatment.

Supercritical oxidation technology has been developed by funding universities and research institutes from government and military organizations such as the US Department of Energy (DOE), NASA, DOD, and the Army and Naval Research Institute. In particular, the focus is on the development of technologies to treat wastewater and waste from chemical weapons and other military chemicals. The oldest company established to commercially apply these findings to industrial wastewater treatment is Modar Inc., which is known to sell the technology to ABB Lummus Crest, Organo of Japan. Modar Inc.'s technology is designed to coexist with supercritical and subcritical regions within the reactor, and to separate and dissolve the solid components into the subcritical region and discharge them from the reactor (US Pat. Nos. 4,338,199, 4,543,190, 4,822,497, 5,106,513, and 5,190,560). The first commercialized facility for supercritical water oxidation technology was installed at Huntsman Corp., Texas, USA, which was installed by research at Eco Waste Technologies and Texas State University. In Japan, the first supercritical hydroxide test facility was built in February 1995 in the central research facility of Organo Corp. in Toda, Tokyo. Organo Corp.'s technology was developed by adopting Modar's technology (1 ton / day of processing capacity) in the United States. Especially, research and development focused on the decomposition of hardly degradable and toxic chloride organic compounds such as PCB, TCE and dioxin. (Japanese Patent Laid-Open No. 9-85075).

However, the supercritical water oxidation method is a problem that corrosion of the device is very large because the oxidation power is very strong. Therefore, since expensive metal materials must be used to prevent corrosion, a lot of equipment costs are required. To solve this problem, techniques are being developed to coat the reactor interior with corrosion resistant materials (US Pat. Nos. 5,461,648, 5,527,471, 5,545,337). The technology to install the double pipe and resist the pressure on the reactor outer wall with a material that resists corrosion was also developed. (US Patent No. 5,591,415, Japanese Patent Application Laid-Open No. 9-085075, PCT Publication WO 9602471, WO 9218426). In addition, a technique of continuously injecting non-corrosive water and the like into the double pipe to prevent direct contact of corrosive substances on the wall has been developed (US Patent Nos. 5,670,040, 5,571,424, 5,571,423, and European Patent Publications). 708058). In addition, another disadvantage is that in the supercritical water, inorganic components precipitate and accumulate on the reactor wall. In order to solve this problem, technologies for dissolving and discharging solids while maintaining the reactor in the supercritical and subcritical regions have been introduced (US Patent Nos. 4,338,199, 4,543,190, 4,822,497, 5,106,513, and 5,190,560). A technology that prevents solids from depositing on the wall by installing a double wall made of a material that allows water to penetrate into the reactor (US Patent Nos. 5,670,040, 5,571,424, 5,571,423, EP 708058) and particles Techniques such as preventing the generation of scale on the wall while flowing (US Pat. No. 5,543,057, PCT Publication WO 9418128), and a method of changing the reactor operating conditions (PCT Publication WO 9519323, WO 9619415) Developed.

Although supercritical water oxidation is a technique that can oxidize almost all organics perfectly, high reaction temperature is required to oxidize organic matter to about 99.99%, and the reactor volume needs to be large because the reactor residence time is long. Thus, inventions that combine catalytic oxidation have been made (US Pat. No. 5,358,646, PCT Publication WO 9111394).

As discussed above, the technology development of supercritical water oxidation method mainly leads to the effective removal of inorganic components precipitated in the reactor, and to solve the problem of causing serious corrosion in the reactor by containing corrosive substances in the waste water or organic matter. It has been focused on. However, the development of a technique for reducing a large amount of energy consumption, which is one of the biggest disadvantages of supercritical water oxidation, is weak. In addition, the invention of grafting catalytic oxidation to supplement the supercritical water oxidation method has been in progress, but the technology has been developed to install a catalytic reactor separately, and even in this case, the development of technology for reducing energy consumption is insignificant.

As mentioned above, supercritical water oxidation techniques have the disadvantage of consuming large amounts of energy. In order to compensate for these drawbacks, some techniques for utilizing energy containing the treated water discharged from the reactor to heat the incoming wastewater have been applied, but there is a demand for developing a technology for improving energy efficiency. In addition, supercritical water oxidation techniques can completely decompose organics, but require high temperatures or long reactor residence times.

Accordingly, it is an object of the present invention to recover heat containing the treated water discharged from the reactor, to cool the bottom of the reactor to the incoming waste liquid, while at the same time the waste liquid is heated to improve energy efficiency and utilize a catalyst, The present invention provides a oxidative decomposition process of an organic matter-containing waste liquid using supercritical water oxidation and catalytic oxidation that can sufficiently maintain high oxidative decomposition efficiency even at a low reaction temperature. In addition, by dissolving the inorganic components precipitated in the supercritical reaction zone to prevent accumulation, and to remove some of the precipitated solids from the reactor smoothly to enable the reactor to operate continuously.

The organic matter oxidation treatment process of the present invention for achieving the above object is a supercritical state of water having an internal pressure of at least 218 atm and an internal temperature of at least 374 ° C in an oxidative decomposition process of an organic matter-containing waste liquid using a supercritical water oxidation method. The upper zone to which more than one thermostat is attached and the subcritical state of water having an internal pressure above 218 atm and an internal temperature below 374 ° C. are cooled by the incoming waste liquid, and the simultaneously introduced waste liquid is heated by the heat of the reactor lower region. Providing a reactor to which a reactor cooler is attached, the lower region including a catalytic reaction layer being present together; Introducing a waste liquid containing organic material into the top of the reactor at a temperature of at least 374 ° C. and at least 218 atmospheres and at an oxidant at a temperature of at least 20 ° C. and at least 218 atmospheres; And releasing the treated water from which the organic matter is oxidized to the outside of the reactor through a discharge pipe from the bottom of the reactor in a subcritical state of water having a temperature of less than 374 ° C. and a pressure of at least 218 atmospheres.

1 is a view schematically showing a process of treating waste liquid containing organic matter according to the present invention.

Figure 2 is a schematic diagram showing a heater and a cooling device for temperature control of the reactor and the reactor of the present invention.

3 is a schematic diagram showing an apparatus for discharging solid particles in a reactor of the present invention.

4 is a schematic diagram of a reactor and a catalytic reaction bed installed in the reactor of the present invention.

* Description of the main parts of the drawing

10: waste liquid 11: pump for high pressure waste liquid injection

12: heat exchanger 13: primary heating waste liquid

14: secondary heating waste liquid 15: waste liquid heater

16: oxidant 17: oxidant and waste liquid mixer

18: oxidant burner 19: oxidant injection tube

20: cooler 21,22,23: reactor heater

24: reactor cooler 25: reactor

26: bottom of the reactor (subcritical zone) 27: discharge pipe

31, 32, 34, 35: valve 33: solids discharge container

41: catalytic reaction layer

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As described above, in the conventional supercritical water oxidation process, development of a technology for improving energy use efficiency has not been well performed. Therefore, in the present invention, a reactor cooler 24 is installed to recover the amount of heat generated in the reactor to efficiently utilize energy and heat the waste liquid introduced therein, and to cool the lower part of the reactor. In addition, the lower part of the reactor cooled by the incoming waste liquid was kept below the critical point of water so that the inorganic material precipitated in the reactor could be dissolved and discharged. Inorganic components dissolved in subcritical water have a sharp decrease in solubility in supercritical water to precipitate as a solid material. The solids thus precipitated contaminate the inner wall of the reactor, making it impossible to operate the reactor for a long time. Therefore, in the process developed in the present invention, the solid particles precipitated in the supercritical state were dropped by gravity below the reactor, and then dissolved in water in the subcritical state to be discharged from the reactor. In addition, a solids discharging system was constructed in which some insoluble solid particles were discharged by the reactor pressure. On the other hand, supercritical water oxidation can completely oxidatively decompose almost all organic materials, but in order to completely oxidatively decompose hardly decomposable substances, the reactor residence time must be increased or the temperature for decomposition is increased. This causes the problem of increasing the energy consumption again or increasing the investment cost, so in the present invention, the catalytic reaction layer is installed in the subcritical region at the bottom of the reactor to efficiently oxidatively decompose the hardly decomposable organic matter even at the same reactor residence time and temperature. To make it possible.

FIG. 1 briefly illustrates an oxidative decomposition process of an organic matter-containing waste solution using the supercritical water oxidation method according to the present invention. The waste liquid 10 containing the organic material is introduced into the heat exchanger 12 after raising to an operating pressure of more than the critical pressure (218 atm) of water through the high pressure injection pump 11. Waste liquids containing organic substances may be waste water, sewage, sludge and organic waste liquids. The heat exchanger 12 is designed to perform the function of cooling the hot treated water discharged from the reactor with the waste liquid supplied to the reactor, and the incoming waste liquid is heated. The waste liquid 13 primarily heated in the heat exchanger 12 is injected into the reactor cooler 24 installed at the bottom of the reactor. The reactor cooler 24 adjusts the reactor bottom to cool to the incoming waste liquid to maintain a temperature below 374 ° C., which is the critical temperature of the water, and the incoming waste liquid is secondarily heated while passing through the reactor cooler 24. Secondly heated waste liquid is heated in the waste liquid heater 15 to the temperature above the critical temperature of water in the third and then flows into the reactor 25. On the other hand, the oxidant 16 is pressurized by the oxidant pressurization device 17 to be above the critical pressure (218 atm) of water and then injected into the oxidant heater 18 so that the reactor is not excessively cooled, and fully utilizes the high oxidizing power of hydrogen peroxide. In order to be heated to 20 ~ 400 ℃ to mix with the waste water in the mixer 19, it is injected into the upper portion of the reactor 25 through the injection pipe. The temperature of the oxidant flowing into the reactor 25 is maintained at 20 ℃ or more, and the oxidant is selected from the group consisting of oxygen, air, gas containing oxygen, hydrogen peroxide, aqueous hydrogen peroxide solution, and liquid containing ozone and oxygen. Can be used. In particular, when the hydrogen peroxide aqueous solution is used as the oxidizing agent, the concentration of hydrogen peroxide can be easily purchased commercially, preferably 0.1 to 70% by weight so as not to decompose naturally in the injection facility. Two or more reactor heaters 21, 22, and 23 are provided so that the upper part of the reactor 25 is maintained above the critical point of water (374 ° C, 218 atmospheres). The waste liquid and the oxidant injected at the top of the reactor are subjected to a rapid oxidation reaction and descend by gravity to the bottom of the reactor. The reactor bottom 26 is cooled by the incoming waste liquid as described above to remain below the critical temperature of the water. The water in the subcritical region has a very high solubility of the inorganic salts, so that the inorganic salts precipitated and dropped in the upper supercritical region are dissolved again. In addition, the remaining organic matter less oxidatively decomposed in the supercritical region is finally oxidized in the catalytic reaction layer 41 installed in the subcritical region and then discharged out of the reactor by the discharge pipe 27. The discharged waste liquid is cooled after being cooled in the heat exchanger 12 and then cooled to room temperature again by the cooler 20, and then discharged.

In the supercritical state of water, the inorganic components dissolved in the waste liquid are precipitated in the reactor, making it impossible to operate the reactor for a long time. For this reason, reactor design is very important in wastewater treatment systems by supercritical water oxidation. As shown in FIG. 2, in the present invention, the supercritical region and the subcritical region of water coexist in the reactor 25. In particular, a reactor cooler 24 is provided so that the subcritical region is cooled by the waste liquid flowing in, and at the same time the waste liquid is heated. The reactor cooler 24 may be in the form of a jacket or coil wound at the bottom of the reactor, in the case of a jacket form, baffles may be installed inside the jacket to improve heat exchange efficiency. The reactor cooler 24 may be generated by oxidatively decomposing organic components in the reactor, or may maximize energy efficiency by recovering a part of heat supplied to maintain the reactor temperature. In addition, the supercritical region of water at the top of the reactor was provided with two or more heaters 21, 22 and 23 to control the temperature above the two regions so as to properly maintain the temperature in the reactor. 2 illustrates a case where three heaters are installed as an example, but FIG. 2 does not represent all the reactor shapes according to the present invention. As shown in FIG. 2, the supercritical region at the top of the reactor is again equipped with a temperature controller to be maintained at two or more different temperatures. In other words, the upper 1/2 to 2/3 of the supercritical zone at the top of the reactor maintains the temperature inside the reactor at 390 ° C or higher in order to rapidly decompose the incoming waste liquid, and the supercritical zone of the remaining water is In order to keep the operation of the subcritical region smoothly, the temperature inside the reactor is preferably maintained in the range of 374 to 400 ° C. In addition, the ratio of the subcritical region of water is designed and operated to be maintained in the range of 5 to 50% by volume of the total reactor volume in order to operate stably in the supercritical and subcritical regions. On the other hand, the treated waste liquid is discharged out of the reactor through a discharge pipe 27 installed in the subcritical region 26 at the bottom of the reactor. This is because the condition of the discharged water is made in the subcritical region of the water, thereby preventing the phenomenon that the inorganic material is deposited inside the discharge pipe and blocks the discharge pipe. Inorganic substances dissolved in the subcritical region of water do not precipitate inside the reactor, but are dissolved in the water in the subcritical region and discharged through the discharge pipe. However, when newly insoluble inorganic substances generated in the reactor are precipitated inside the reactor, the reactor is extended for a long time. It becomes impossible to drive. Therefore, a facility for discharging insoluble inorganic particles (solids) generated in the reactor was installed in the lower part of the reactor as shown in FIG. 3. Solids collected in the lower subcritical region in the reactor 25 are collected in the solids discharge container 33 through two valves 31 and 32 which operate sequentially. The volume of the solid discharge container 33 is 1 to 10% by volume of the total volume of the reactor, or 10 to 50% by volume of the reactor subcritical zone volume because the pressure fluctuation of the reactor may become unstable when the solids discharge, the operation of the supercritical water may be unstable. It is designed as a range. The discharge of the inorganic particles is instantaneous because the reactor pressure is high pressure, and the inorganic material collected in the container 33 is discharged by opening the valve 35 installed in the lower part of the container after the pressure is lowered by the pressure relief valve 34.

Organics contained in the waste liquid are sufficiently oxidized in the supercritical region of water, but there is a possibility that traces of hardly decomposable substances are less decomposed. In order to sufficiently oxidize such trace hardly decomposable substances, a large reactor residence time is required or problems such as performing an oxidation reaction at a high temperature are generated. In order to compensate for these disadvantages, a catalytic reaction layer 41 was installed inside the reactor to decompose most organic contaminants by supercritical water oxidation and then perform catalytic oxidation. That is, as shown in Figure 4, the oxidized waste liquid in the supercritical water region of water is converted most of the organic matter to carbon dioxide and water. However, the less decomposed trace organics are brought down to the subcritical region of water at the bottom of the reactor, and then catalytically oxidized again through the catalytic reaction layer 41 installed in the subcritical region, converted to carbon dioxide and water, and then the discharge pipe 27 is opened. Is discharged out of the reactor. The catalytic reaction layer 41 includes an alumina phase on which one to four transition metal oxides are supported; An alumina phase on which one or more precious metals selected from the group consisting of platinum, silver and gold are supported together with the oxide; A net coated with 50 to 200 mesh stainless steel with one or more precious metals selected from the group consisting of platinum, silver and gold; A mesh of 50 to 200 mesh mixed with one or more precious metals selected from the group consisting of platinum, silver and gold; Sponge phases of one or more precious metals selected from the group consisting of platinum, silver and gold; Honeycomb structures of one or more supported metal oxide components from the group consisting of transition metal oxides, platinum, silver and gold; Or mixtures thereof.

As described above, the present invention is to cool the reactor with the incoming waste liquid, to install a reactor cooler in which the waste liquid is heated, in order to reduce a large amount of energy consumption which is pointed out as a problem of the supercritical water oxidation method, to prevent accumulation of solid components in the reactor. In addition, the precipitated solid particles were smoothly removed to ensure continuous operation of the reactor. In addition, in order to efficiently decompose the trace organic matter less decomposed by supercritical water oxidation, the catalytic reaction layer 41 is installed in the subcritical region at the bottom of the reactor so that high efficiency decomposition performance can be obtained even at a small reactor volume and low temperature. It was.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Example 1

Example of reactor cooler in supercritical water and catalytic oxidation treatment of industrial wastewater

The high concentration industrial wastewater was oxidatively decomposed using the initial particle count oxidation and catalytic oxidation. A reactor of the type shown in FIG. 1 was used, and the reactor cooler was operated to observe the possibility of reducing the energy usage. The energy consumption could not be measured directly, and the temperature of each part of the process could be measured to compare the energy saving potential of the reactor cooler.

The industrial wastewater was dark brown and the COD _Cr was 20,560 mg / l, which was very polluted. The pressure of the reactor was maintained at 272 atm, and the residence time in the reactor was 2 minutes. 35% by weight of hydrogen peroxide aqueous solution was used as an oxidizing agent, and CuO-ZnO-Al ₂ O ₃ (weight ratio of 50:30:20) was prepared as particles having an average diameter of 2 mm and catalyzed in a conventional fixed bed form. The layers were installed and pretreated with an aqueous hydrogen peroxide solution for 30 minutes before the reaction started. Table 1 below compares the temperature of each part of the process with and without the reactor cooler.

As shown in Table 1, when using the reactor cooler by increasing the temperature of the wastewater flowing into the wastewater heater 110 ℃ to confirm that there is an effect that can reduce the energy used in the wastewater heater by 508.4kJ per kg of wastewater Could. This shows that the use of the reactor cooler has the effect of saving 29.4% of the energy used in the waste water heater.

Supercritical water of industrial wastewater and the temperature of each part in the process of catalytic oxidation Process point temperature (℃) Reactor cooler When using When not in use Wastewater Inlet Temperature 15 15 Oxidant inlet temperature 30 30 After heat exchanger 190 195 Waste Heater Shear 300 190 After the waste water heater 410 410 Reactor top 400 400 Reactor shutdown 390 393 Catalytic Reaction Bed 360 360 Reactor bottom 345 350

Example 2

Supercritical and Catalytic Oxidation Results of Industrial Wastewater 1

High concentration of industrial wastewater was oxidized in the supercritical state of water, and then catalytically oxidized through a catalytic reaction layer installed in a subcritical region. The COD _Cr of the raw wastewater was 20,560 mg / l and the color was dark brown. Reactor pressure was 272 atm, oxidizing agent was used 35% by weight aqueous hydrogen peroxide solution, as a catalyst CuO-ZnO-Al ₂ O ₃ (weight ratio of 50:30:20) of particles of average diameter 2mm to form a fixed bed It was installed in the catalytic reaction layer, and pretreated with an aqueous hydrogen peroxide solution for 30 minutes before starting the reaction. The reactor residence time was maintained for 2 minutes including 30 seconds of catalyst bed residence time. The results of this example are shown in Table 2 below. As can be seen in Table 2, when combined with catalytic oxidation it can be seen that almost all the organic matter contained in the waste water oxidative decomposition even at a temperature of 450 ℃.

Initial Coefficient and Catalytic Oxidation Result of Industrial Wastewater 1 Reactor Top Temperature (℃) 400 430 450 Reactor shutdown temperature (℃) 390 405 420 Catalytic Reaction Bed Temperature (℃) 360 365 365 Reactor bottom temperature (℃) 345 350 355 Wastewater (COD _Cr (mg / ℓ) 20,560 20,560 20,560 Treated water (COD _Cr (mg / ℓ) 157 32 5 Throughput% 99.2 99.84 99.98

Comparative Example 1

Comparison of Supercritical and Catalytic Oxidation and Supercritical Water Oxidation of Industrial Wastewater

After oxidizing the high concentration industrial wastewater in the supercritical state of water, the result of catalytic oxidation through the catalytic reaction layer installed in the subcritical zone was compared with the result of supercritical water oxidation only. The comparison results are shown in Table 3 below. As can be seen from Table 3, the treatment of both supercritical water oxidation and catalytic oxidation can be almost completely treated at 450 ℃ wastewater, but when treated only with supercritical water oxidation can be confirmed that the results of oxidative decomposition rate is significantly different.

Comparison of Supercritical and Catalytic Oxidation and Supercritical Water Oxidation of Industrial Wastewater Item Supercritical Water and Catalytic Oxidation Supercritical water oxidation Reactor Top Temperature (℃) 4500 450 Reactor shutdown temperature (℃) 420 420 Catalytic Reaction Bed Temperature (℃) 365 - Reactor bottom temperature (℃) 355 355 Wastewater (COD _Cr (mg / ℓ) 20,560 17,800 Treated water (COD _Cr (mg / ℓ) 5 265 Throughput% 99.98 98.5

Example 3

Supercritical and Catalytic Oxidation Results of Industrial Wastewater 2

High concentration of industrial wastewater was oxidized in the supercritical state of water, and then catalytically oxidized through a catalytic reaction layer installed in a subcritical region. The COD _Cr of the raw wastewater was 20,560 mg / l and the color was dark brown. The reactor pressure was 272 atm, and the oxidant used 35 wt% aqueous hydrogen peroxide solution, and as a catalyst, a small amount of gold (4.7 wt%) was added to CuO-ZnO-Al ₂ O ₃ (50:30:20 weight ratio), and the average diameter was Prepared with particles of 2mm and installed in the catalytic reaction layer in the form of a fixed bed, it was pretreated using hydrogen peroxide aqueous solution for 30 minutes before the start of the reaction. The results of this example are shown in Table 4 below. Comparing Table 2 and Table 4, when using a catalyst with a small amount of gold, the decomposition rate at 400 ℃ was further increased compared to the case without addition, it was confirmed that the tendency to decrease slightly at 430 ℃ and 450 ℃.

Supercritical and Catalytic Oxidation Results of Industrial Wastewater 2 Reactor Top Temperature (℃) 400 430 450 Reactor shutdown temperature (℃) 390 405 420 Catalytic Reaction Bed Temperature (℃) 360 365 365 Reactor bottom temperature (℃) 345 350 355 Wastewater COD _Cr (mg / ℓ) 20,560 20,560 20,560 Treated Water COD _Cr (mg / ℓ) 103 308 185 Throughput% 99.5 98.5 99.1

Example 4

Supercritical and Catalytic Oxidation Results of Industrial Wastewater 3

High concentration of industrial wastewater was oxidized in the supercritical state of water, and then catalytically oxidized through a catalytic reaction layer installed in a subcritical region. The COD _Cr of the raw wastewater was 20,560 mg / l and the color was dark brown. The reactor pressure was 272 atm, and the oxidizing agent used 35 wt% aqueous hydrogen peroxide solution, and as a catalyst, a small amount (4.5 wt%) of silver was added to CuO-ZnO-Al ₂ O ₃ (50:30:20 weight ratio) to obtain an average diameter. Prepared with particles of 2mm and installed in the catalytic reaction layer in the form of a fixed bed, it was pretreated using hydrogen peroxide aqueous solution for 30 minutes before the start of the reaction. The results of this example are shown in Table 5 below.

Supercritical and Catalytic Oxidation Results of Industrial Wastewater 3 Reactor Top Temperature (℃) 400 430 450 Reactor shutdown temperature (℃) 390 405 420 Catalytic Reaction Bed Temperature (℃) 360 365 365 Reactor bottom temperature (℃) 345 350 355 Wastewater COD _Cr (mg / ℓ) 20,560 20,560 20,560 Treated Water COD _Cr (mg / ℓ) 185 102 62 Throughput% 99.1 99.5 99.7

Example 5

Supercritical and Catalytic Oxidation Results of Industrial Wastewater 4

High concentration of industrial wastewater was oxidized in the supercritical state of water, and then catalytically oxidized through a catalytic reaction layer installed in a subcritical region. The COD _Cr of the raw wastewater was 20,560 mg / l and the color was dark brown. Reactor pressure was 272 atm, oxidizing agent was used 35% by weight of hydrogen peroxide aqueous solution, gold was coated on a stainless steel mesh as a catalyst, and pre-treated with an aqueous hydrogen peroxide solution for 30 minutes before the start of the reaction. The results of this example are shown in Table 6 below.

Supercritical and Catalytic Oxidation Results of Industrial Wastewater 3 Reactor Top Temperature (℃) 400 430 450 Reactor shutdown temperature (℃) 390 405 420 Catalytic Reaction Bed Temperature (℃) 360 365 365 Reactor bottom temperature (℃) 345 350 355 Wastewater COD _Cr (mg / ℓ) 20,560 20,560 20,560 Treated Water COD _Cr (mg / ℓ) 596 411 288 Throughput% 97.1 98.0 98.6

As described above, the present invention has developed a process for oxidatively decomposing organic matter-containing waste liquid using supercritical water oxidation and catalytic oxidation. In the present invention, the supercritical water oxidation process using a large amount of energy was developed to develop a process capable of sufficiently recovering energy, and thus, there is an effect of reducing energy usage while showing decomposition efficiency such as copper. In addition, by developing a reactor that combines supercritical water oxidation and catalytic oxidation, there is an effect of obtaining high efficiency decomposition performance even at a low reactor volume and low temperature. In addition, by recovering the energy generated in the reactor or supplied to the reactor by partial cooling of the reactor, it also prevents the precipitation of inorganic materials in the reactor, and effectively removes some of the precipitated inorganic components, thereby improving the operational stability of the supercritical water oxidation process. .

Claims (10)

In the oxidative decomposition process of the organic matter-containing waste liquid using the supercritical water oxidation method, A supercritical state of water with an internal pressure of at least 218 atm and an internal temperature of at least 374 ° C, an upper region with at least two temperature regulators and a subcritical state of water with an internal pressure of at least 218 atm and an internal temperature of less than 374 ° C, Providing a reactor having a lower region to which the reactor cooler is attached, which is cooled by the incoming waste liquid and simultaneously introduced into the waste liquid is heated by heat of the reactor lower region; Introducing a waste liquid containing organic material into the top of the reactor at a temperature of at least 374 ° C. and at least 218 atmospheres and at an oxidant at a temperature of at least 20 ° C. and at least 218 atmospheres; And The treated water from which the organic matter is oxidized is discharged from the bottom of the reactor through the discharge pipe to the bottom of the reactor or to the bottom in a subcritical state of water at a temperature of less than 374 ℃ and a pressure of 218 atmosphere or more; Oxidative decomposition process of wastewater containing organic matter using supercritical water oxidation and catalytic oxidation, characterized in that the catalytic reaction layer is included in the lower region of the reactor. According to claim 1, wherein the upper region is 50 to 95% by volume of the total volume of the reactor, the lower region of the organic material containing wastewater using supercritical water oxidation and catalytic oxidation characterized in that 5% to 50% by volume of the reactor. Oxidative decomposition process. According to claim 1, wherein the upper 1/2 to 2/3 of the upper region of the inside of the reactor is maintained at a temperature of 390 ℃ or more, the rest of the temperature in the reactor is maintained at a temperature range of 374 to 400 ℃ Oxidative decomposition process of the organic matter-containing waste liquid using supercritical water oxidation and catalytic oxidation. The method of claim 1, wherein the oxidizing agent is one selected from the group consisting of oxygen, air, gas containing oxygen, hydrogen peroxide, aqueous hydrogen peroxide solution, and liquid containing ozone and oxygen. Oxidative decomposition process of waste liquid containing organic matter. The oxidative decomposition process of an organic matter-containing waste solution using supercritical water oxidation and catalytic oxidation according to claim 4, wherein the hydrogen peroxide concentration of the aqueous hydrogen peroxide solution is 0.1 to 70% by weight and the reactor injection temperature is 20 to 400 ° C. The oxidative decomposition process of an organic matter-containing waste liquid using supercritical water oxidation and catalytic oxidation according to claim 1, wherein the waste liquid is sewage, waste water, sludge and organic waste liquid. The method of claim 1, wherein the heat exchanger attached to the lower region is of the jacket form, the jacket form with a baffle inside, or the coil wound form oxidative decomposition of the organic matter-containing waste liquid using supercritical water oxidation and catalytic oxidation fair. According to claim 1, wherein the solid particles accumulate in the lower region is discharged together with the water of the subcritical state using the reactor pressure is collected in the solid discharge vessel, characterized in that the waste containing organic matter containing supercritical water oxidation and catalytic oxidation Oxidative decomposition process. The method of claim 8, wherein the volume of the solids discharge vessel is 1 to 10% by volume of the total volume of the reactor, or 10 to 50% by volume of the subcritical region of the lower portion of the reactor using supercritical water oxidation and catalytic oxidation Oxidative decomposition process of waste liquid containing organic matter. The alumina phase of claim 1, wherein the catalytic reaction layer is supported with one to four transition metal oxides; An alumina phase on which one or more precious metals selected from the group consisting of platinum, silver and gold are supported together with the oxide; A net coated with 50 to 200 mesh stainless steel with one or more precious metals selected from the group consisting of platinum, silver and gold; A mesh of 50 to 200 mesh mixed with one or more precious metals selected from the group consisting of platinum, silver and gold; Sponge phases of one or more precious metals selected from the group consisting of platinum, silver and gold; Honeycomb structures of one or more supported metal oxide components from the group consisting of transition metal oxides, platinum, silver and gold; Or oxidative decomposition of an organic matter-containing waste liquid using supercritical water oxidation and catalytic oxidation, characterized in that they are a mixed catalyst.