KR100625882B1 - The process for oxidative decomposition of wastewater containing organic material by supercritical conditions - Google Patents

Abstract

The present invention relates to a process for oxidatively decomposing an organic matter-containing waste liquid, and more particularly, in the oxidative decomposition process of an organic matter-containing waste liquid using a supercritical water oxidation method, in order to prevent corrosion generated during the preheating of the organic-containing waste liquid. Preheating to anoxic conditions by addition of neutralizing agent; Equipped with a preheating mixer to rapidly raise the waste liquid preheated to the subcritical temperature to the supercritical temperature by using an oxidizing agent, a neutralizer and an auxiliary heat source to prevent corrosion and precipitation of inorganic substances; The discharge temperature of the preheater maintains a supercritical temperature to prevent corrosion at the reactor inlet; A reactor having a high linear velocity is installed to prevent blockage by precipitation of inorganic materials; In order to prevent corrosion and precipitation of inorganic substances during cooling of the treated water discharged at a temperature above 450 ° C, supercritical water oxidation method in which a quench mixture is provided in the 300 to 374 ° C area between the supercritical heat exchanger and the subcritical heat exchanger is used. The oxidative decomposition process of the used organic matter containing waste liquid is related. In order to prevent corrosion and precipitation of inorganic substances, the present invention uses a preheat mixer to raise the waste liquid containing organic matter, which must be preheated to 350 ° C. or lower, in anoxic conditions, to a supercritical temperature of 374 ° C. or higher without corrosion and precipitation of inorganic substances. By injecting to minimize the possible corrosion zone of subcritical conditions under aerobic acid to prevent corrosion and precipitation of inorganic materials at the inlet of the reactor, and to prevent corrosion and precipitation of inorganic materials during cooling of the treated water, a cooling mixer is installed to supercritical water oxidation Long term operation stability of the process was ensured.

Supercritical water, oxidative decomposition, organic waste liquid, corrosive substances, inorganic material precipitation

Description

The process for oxidative decomposition of wastewater containing organic material by supercritical conditions}             

1 is a schematic diagram of a supercritical water oxidative decomposition process of an organic matter-containing waste liquid according to the present invention.

 2 is a schematic diagram of a preheating mixer according to the present invention.

Figure 3 shows the emissions of inorganic materials in the reactor according to the present invention.

    <Description of reference numerals for main parts of the drawings>

11: organic matter-containing waste liquid 12: oxidizing agent

13: neutralizing agent 14: auxiliary heat source

21: oxidant pressurization device 22: neutralizer pump

23: auxiliary heat source pump 24: organic matter-containing waste pump

31: waste liquid heater 32: auxiliary heat source heater

33: preheater 34: reactor

35 supercritical heat exchanger 36 quench mixer

37 subcritical heat exchanger 38 pressure reducing device

39: pressure drop valve

41: gas-liquid separator 42: quench water pump

43: exhaust gas 44: treated water

111: waste solution inlet tube containing organic matter 112: oxidant inlet

113: neutralizer inlet 114: auxiliary heat source inlet

115: oxidant inlet 116: reaction mixture outlet

117: inner wall of the preheat mixer 118: outer wall of the preheat mixer

The present invention relates to the supercritical water oxidative decomposition of wastewater containing organic matter, and specifically, for the treatment of organic wastewater such as wastewater, sewage, sludge, etc. containing high concentration, corrosive, hardly decomposable or toxic organic matter which is difficult to be treated by biological treatment. Oxidative decomposition of organic wastes containing supercritical water using supercritical water oxidation method by reacting organic wastes at temperatures and pressures above the critical point of water to oxidize organic matters contained in the wastes into harmless components such as carbon dioxide and water to remove organic substances. An apparatus and an oxidative decomposition method of an organic matter containing waste liquid by the supercritical water oxidation method using the said apparatus are provided.

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 scheme, but the biological treatment scheme is not suitable for the treatment of wastewater and waste liquor containing a high concentration of organic matter, or particularly containing hardly decomposable organic or toxic organic matter. . In order to solve this problem, a technique that has been developed in recent years is a wastewater treatment technology by supercritical water oxidation method. Supercritical water oxidation is a method of adjusting the water above a critical point (temperature 374 ° C., pressure 218 atmospheres) instead of maintaining the contaminant water itself in a liquid phase and oxidizing the contaminant in the presence of an oxygen source such as oxygen or air. Oxidation reactions in supercritical water exert more than 99.99% of most organic contaminants within minutes. In this case, the main products are water, carbon dioxide, etc., and the final aqueous solution mixture is harmless, so it can be discharged as it is without any special aftertreatment.

In particular, in order to prevent corrosion and precipitation of inorganic matters, which are pointed out as a problem in the supercritical water oxidation treatment of organic wastes, the waste liquid is preheated to anoxic conditions after adding a neutralizing agent to the waste liquid, and the waste liquid preheated to a subcritical temperature is oxidized and neutralized. And a preheated auxiliary heat source to quickly rise to the supercritical temperature in the preheater, realize a high flow rate in the reactor to prevent clogging of the reactor due to precipitation of inorganic materials, and the energy of the high temperature treated water discharged to the supercritical temperature. Supercritical heat exchanger to recover in the supercritical water with little corrosion, and to install the quenching mixture to prevent corrosion and precipitation of inorganic substances in the cooling process of the treated water to secure the stability and continuous operation of the supercritical water oxidation process It was.

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., ABB Lummus Crest, Organo Corp. of Japan. It is known that the technology was sold to the back. Modar Inc.'s technology is designed to coexist with supercritical and subcritical zones in a reactor, and to separate and dissolve inorganic materials into subcritical zones and discharge them from the reactor [US Pat. Nos. 4,338,19, 4,543,190]. , 4,822,49, 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 constructed as a result of research by Eco Waste Technologies and Texas State University. In Japan, the first supercritical water oxidation test facility was built in February 1995 within the central research facility of Organo Corp. in Toda, Tokyo. Organo Corp.'s technology was developed by introducing Modar's technology (1 ton / day of treatment capacity) in the United States, and is being researched and developed in particular for the decomposition of hardly degradable and toxic chloride organic compounds such as PCB, TCE and dioxin. Japanese Patent Laid-Open No. 9-85075].

However, supercritical water oxidation has a strong oxidation power, which is a problem of corrosion of the device. Therefore, expensive metal materials must be used to prevent corrosion, which requires a lot of equipment costs. To solve this corrosion problem, techniques for coating the inside of the reactor with corrosion resistant materials have been developed [US Pat. Nos. 5,461,648, 5,527,471, 5,545,337]. Reactor outer walls have also been developed with low cost metals (US Pat. No. 5,591,415, Japanese Patent Laid-Open No. 9-85075, PCT Publication WO9602471, WO9218426). In addition, a technology for continuously injecting non-corrosive water into the double pipe continuously and preventing direct contact with corrosive substances on the wall has been developed [US Patent Nos. 5,670,040, 5,571,424, 5,571,423, and European Patent Publication No. 708058]. Another drawback is the precipitation of inorganic material in the supercritical water, which builds up on the reactor walls. To solve this problem, melting and discharging inorganic materials while maintaining the reactor in the supercritical and subcritical regions [US Pat. Nos. 4,338,199, 4,543,190, 4,822,497, 5,106,513, and 5,190,560], and water in the reactor Technology to prevent the precipitation of inorganic material on the wall by installing a double wall with a material that can permeate [US Patent Nos. 5,670,040, 5,571,424, 5,571,423 and European Patent No. 708058] Techniques for preventing the occurrence of scale in the US [US Patent Nos. 5,543,057 and PCT Publication No. WO9418128], and a method of changing reactor operating conditions [PCT Publications WO9519323 and WO9619415] have been developed.

As such, the technology development of supercritical water oxidation method has been mainly focused on solving the problem of containing the corrosive substances in the waste liquid and causing the serious corrosion in the reactor and effectively removing the inorganic substances deposited in the reactor. However, corrosion occurs more seriously in the preheating process of waste liquids containing corrosive and inorganic substances and in the heat exchange of treated water discharged at supercritical temperatures than in the reactor walls under supercritical conditions. In the case of the waste liquid containing the organic matter, there is a problem that the inorganic material is seriously precipitated during the heat exchange process of the waste liquid heater, the reactor wall and the treated water. However, in the supercritical water oxidation treatment of wastewater containing organic matter containing corrosive and inorganic substances, it is possible to completely solve the corrosion and precipitation of inorganic substances that occur during the preheating of the wastewater as well as the heat exchange of the treated water as well as the supercritical reactor. Development is weak.

As discussed earlier, supercritical water oxidation technology, despite the advantages of enabling complete organic decomposition, does not generate corrosion and inorganic materials in superheated water reactors, reactors, and heat exchangers during supercritical water oxidation of organic wastes containing corrosive and inorganic materials. It has the disadvantage of precipitation. In order to overcome the disadvantages of corrosion in the reactor, reactor design of the structure to prevent contact with the reactor material of the organic liquid containing corrosive material and inorganic material, installation of the inner wall of the corrosion protection material inside the reactor, Many methods have been proposed, including food reduction. However, severe corrosion occurs during the preheating of organic wastes containing corrosive and inorganic materials and the cooling of supercritical water oxidized water, and the corrosion in the supercritical reactor is rather insignificant. In particular, the neutralizing agent administered to suppress the corrosion generated during the supercritical water oxidation treatment of organic wastes containing corrosive substances and inorganic substances is used for the precipitation of inorganic substances during the heat of the waste liquid, the inlet of the reactor under supercritical conditions, and the cooling of the treated water. Stable operation requires very careful consideration to prevent corrosion and precipitation of inorganic materials throughout the supercritical oxidation process as well as the reactor.

One of the most successfully evaluated types of reactors proposed to prevent corrosion and precipitation of inorganic materials is to provide a porous inner wall of anticorrosive material inside the reactor to prevent corrosion and precipitation of inorganic materials. The hot water is injected into the water, and in order to prevent the precipitation of inorganic substances at the outlet of the reactor, the cooling water is directly added to the treated water to reduce the temperature. In another form, a tubular reactor that ignores minor supercritical corrosion and pushes the precipitated inorganic material at a high flow rate is considered. However, the tubular reactor also uses cooling water in the treated water to prevent corrosion of the treated water and precipitation of inorganic materials. Directly reduce the temperature. This concept and sedimentation concept can suppress corrosion and precipitation of inorganic materials in the reactor under supercritical conditions.However, the corrosion of the wastewater containing the organic matter containing corrosive and inorganic materials and the cooling process It is difficult to completely prevent the precipitation of inorganic substances. In particular, it is difficult to prevent corrosion in some subcritical sections under aerobic formation formed near the reactor inlet of the waste liquid preheated to subcritical temperature in order to prevent the precipitation of inorganic materials, and to prevent the precipitation of inorganic materials during the discharge of treated water. Even in some subcritical sections under aerobic formation formed by the cooling water administered, it is difficult to completely prevent corrosion. In addition, due to the neutralizing agent generally administered to inhibit corrosion, the problem of precipitation of inorganic substances in the preheating of the waste liquid, the reaction of the organic matter, and the cooling of the treated water becomes more serious.

Accordingly, an object of the present invention is to oxidatively decompose an organic matter-containing waste liquid using a supercritical water oxidation method which can prevent the blockage by corrosion and precipitation of inorganic substances in the waste-heater, the reactor and the heat exchanger during the supercritical water oxidation treatment of the organic matter-containing waste liquid. In addition, by improving the supercritical water oxidation process, which consumes a large amount of energy to prevent the precipitation of inorganic substances, supercritical heat exchanger and quenching mixer are installed to prevent corrosion of the treated water and precipitation of inorganic substances and to save energy. Of the subcritical condition formed at the inlet of the reactor by rapidly raising the reactor injection temperature of the organic-containing waste liquid to the supercritical temperature by using a preheated auxiliary heat source. Corrosion in the reactor can be prevented by minimizing possible corrosion The present invention provides a oxidative decomposition apparatus for an organic matter-containing waste liquid using a supercritical water oxidation method, and as another object, a method for oxidative decomposition of an organic matter-containing waste liquid by a supercritical water oxidation method using the above apparatus.

The present invention relates to supercritical water oxidative decomposition of an organic matter-containing waste liquid, and more particularly, to the treatment of organic waste liquids such as wastewater, sewage, sludge, etc. containing high concentration, corrosive, hardly decomposable or toxic organic matter, which are difficult to be treated by biological treatment. In order to oxidize the organic matter-containing waste solution using supercritical water oxidation method, the organic matter-containing waste solution is reacted at a temperature and pressure above the critical point of water to oxidize the organic matter contained in the waste solution to harmless components such as carbon dioxide and water to remove the organic substances as the pollutants. A decomposition apparatus and a oxidative decomposition method of an organic matter containing waste liquid by the supercritical water oxidation method using the said apparatus are provided.

Hereinafter, an apparatus for oxidative decomposition of organic matter-containing waste liquid using the supercritical water oxidation method according to the present invention will be described in detail with reference to FIGS. 1 and 2.

1 is a schematic diagram of a supercritical water oxidative decomposition process of an organic matter-containing waste liquid according to the present invention, Figure 2 is a schematic diagram of a preheating mixer according to the present invention.

An apparatus for oxidative decomposition of an organic matter-containing waste solution using the supercritical water oxidation method according to the present invention includes: a waste-liquid heater 31 for preheating the mixture of the organic matter-containing waste solution 11 and the neutralizing agent 13 to a subcritical temperature under anoxic conditions; A preheat mixer (33) which allows the waste liquid preheated from the waste liquid heater (31) to be mixed with the pressurized oxidant (12), the neutralizing agent (13) and the auxiliary heat source (14) which is preheated by heat exchange with the treated water of the reactor; A reactor 34 which rises to a supercritical temperature by an exothermic reaction of the preheated auxiliary heat source, and the organic matter-containing waste liquid discharged from the preheater 33 maintains a high flow rate and undergoes an organic oxidation reaction; A supercritical heat exchanger (35) which heats the treated water discharged from the reactor (34) to a supercritical temperature and heats the auxiliary heat source (14) while cooling the treated water above the supercritical temperature; A quench mixer (36) for quenching the treated water by mixing the treated water passing through the supercritical heat exchanger (35) with quenched water; A subcritical heat exchanger (37) which heats the mixed water discharged from the quench mixer (36) and the organic matter-containing waste liquid (11) to further cool the mixed water and simultaneously heat the organic-containing waste liquid (11); A pressure reducing device 38 and a pressure drop valve 39 for reducing the pressure of the mixed water; A gas-liquid separator 41 for separating the reduced pressure of the treated water into a gas phase and a liquid phase; Characterized in that consists of.

As shown in FIG. 2, the preheater 33 is a structure for preventing corrosion and precipitation of inorganic materials, and is closed to the preheater outer wall 118 and the outlet 116, and a portion adjacent to the inlet is in communication with the preheater. Preheat mixer inner wall 117; It is provided on the preheat mixer outer wall 118 adjacent to the outlet 116, the oxidant inlet 115 to be introduced into the preheat mixer to pass through the communication site in the opposite direction to the flow of the reaction mixture between the outer wall and the inner wall of the preheat mixer. ); An auxiliary heat source injection port 114 having a nozzle communicating with an outer wall of the inlet side preheating mixer; It is divided into a neutralizing agent inlet 113, organic matter-containing waste liquid inlet 111, oxidant inlet 112 from the center is provided in the preheating mixer is composed of a triple pipe extending to the area near the outlet 116.

The preheating mixer 33 has the above configuration, and the supercritical temperature is used for the organic material-containing waste liquid injected at subcritical temperature and the oxidizing agent and neutralizer at room temperature to prevent corrosion and inorganic matters occurring during the preheating process using an auxiliary heat source. As a result of the instantaneous rise to the reactor 34, the section in which corrosion occurs is minimized, and clogging due to precipitation of inorganic materials is also prevented.

On the other hand, in order to cause a rapid exothermic reaction in the preheating mixer 33, the preheating of the auxiliary heat source is first required at a temperature higher than the supercritical temperature. However, when the preheating of the auxiliary heat source is performed in the presence of an oxidizing agent, a considerable amount of heat is generated before reaching the preheating mixer 33. Decomposition of organic matter proceeds, and thus the desired exothermic reaction cannot be obtained in the preheating mixer 33. In addition, the preheating of the auxiliary heat source is carried out in anoxic conditions because it is necessary to suppress the corrosion that may occur during the auxiliary heat source preheating process.

Therefore, the organic pre-mixed waste, oxidizing agent and neutralizing agent are rapidly raised to supercritical temperature and injected into the reactor 34 using the preheater 33 to prevent blockage by precipitation of inorganic materials. There is no formation of critical temperature zones, which can suppress corrosion, and the linear velocity several times faster than subcritical conditions greatly reduces the likelihood of precipitation of inorganic materials, and maintains the supercritical temperature from the inlet of the reactor to increase organic decomposition effects. Can be.

In order to prevent corrosion of the preheating process, the organic matter-containing waste solution 11 is added with a neutralizing agent so that no blockage due to precipitation of inorganic substances occurs in the preheating process of the organic matter-containing waste solution 11 and preheated to a temperature of 350 ° C. or less under anoxic conditions. And injected into the preheater 33, and the remaining neutralizing agent required is directly injected into the preheater at room temperature.

Some of the oxidant 12 injected into the oxidant inlet tube 112 at room temperature to decompose the organic material performs the adiabatic role of the waste containing organic matter and the neutralizer inlet tube in the preheating mixer maintained at high temperature by exothermic reaction of the auxiliary heat source. Thus, it serves to prevent the precipitation of inorganic substances in the organic matter-containing waste liquid inlet pipe 111 and the neutralizer inlet pipe 113 that extends near the reaction mixture outlet 116 of the preheater, and is injected into the oxidant inlet 115. Some of the oxidant flowing between the inner wall of the preheat mixer 117 and the outer wall 118 in the direction opposite to the flow direction of the mixed fluid and introduced into the inner wall of the preheat mixer is supplied to the auxiliary heat source inlet 114. The heat source is oxidized and raised to a high temperature of 600 ° C. or higher, and then mixed with the organic matter-containing waste liquid injected at a subcritical temperature and some oxidizing agents and neutralizing agents at room temperature. The secondary heat source preheated to the supercritical temperature in a supercritical fluid state of 374 ° C. or higher, such as a supercritical temperature, rapidly changes the reactor 34 injection temperature of organic waste containing waste from subcritical to supercritical temperature. The rise minimizes the potential for corrosion of subcritical conditions under aerobic conditions and prevents corrosion at the inlet of the reactor 34 as well as the preheater 33. Some of the oxidant at room temperature injected into the oxidant inlet 115 for the exothermic reaction of the auxiliary heat source preheated to the supercritical temperature controls the temperature of the exothermic reaction by controlling the injection amount, and rises to a high temperature by the exothermic reaction (33) In addition to acting as a thermal insulation to protect the material of the), it prevents the penetration of the organic matter-containing waste liquid to the outer wall 118 of the preheating mixer to block the possibility of corrosion. In particular, by lowering the surface temperature of the inner wall of the preheat mixer (117) of the anticorrosive material located near the reaction mixture outlet (116) of the preheat mixer (33) to the subcritical temperature, the inorganic material precipitates by increasing the solubility of the inorganic material near the surface of the inner wall. Plays an important role in preventing. Protecting the material of the preheating mixer 33 from the exothermic reaction, preventing the infiltration of the waste containing organic matter and lowering the surface temperature of the inner wall 117 of the preheating mixer near the reaction mixture outlet 116 to increase the effect of suppressing the precipitation of inorganic substances. To this end, a small amount of distilled water may be mixed with some oxidant injected into the oxidant inlet 115 at room temperature. The preheat mixer inner wall 117 of the anticorrosive material not only splits each flow but also prevents the organic-containing waste liquid from contacting the preheat mixer outer wall 118 directly at subcritical temperature. The preheating mixer inner wall 117 of the anticorrosive material is preferably made of a metal selected from corrosion resistant materials such as titanium, tantalum, iridium, nickel alloy, and the like.

In the apparatus according to the present invention, the reactor 34 is preferably a tubular reactor, and the pressure reducing device 38 for reducing the pressure of the mixed water provided at the rear end of the subcritical heat exchanger 37 may include a capillary pressure reducer, an orifice pressure reducer, and a pressure reducer. It is preferable to be installed in parallel or in series, or a mixed arrangement of parallel and series in a group selected from two or more from the group such as a valve.

Hereinafter, the oxidative decomposition method of the waste containing organic matter by the supercritical water oxidation method using the apparatus according to the present invention will be described in detail.

The oxidative decomposition method of the waste containing organic matter by the supercritical water oxidation method according to the present invention comprises a) mixing a part of the neutralizing agent 13 into the waste containing organic matter 11 and pressurizing it to at least 218 atmospheres, which is a reaction pressure under anoxic conditions, and subcritical heat exchanger. Preheating to a temperature of 350 ° C. or lower by the 37 and the waste liquid heater 31 and continuously injecting the preheater 33 into the preheater 33; b) pressurizing the oxidizing agent and the neutralizing agent to the reaction pressure of 218 atmospheres or more and injecting the oxidizing agent inlet 112 and the neutralizing agent inlet 113 installed in the preheating mixer 33, and the remaining part of the oxidant is the preheating mixer ( 33 is continuously injected into the preheating mixer 33 through the oxidant inlet 115 adjacent to the reaction mixture outlet 116 of 33) and flows in the direction opposite to the flow direction of the reaction mixture to flow into the inner wall 117 of the preheating mixer. Mixing the auxiliary heat source with the reaction mixture after the oxidation reaction is initiated; c) Treatment water discharged to the supercritical temperature from the reactor 34 by pressurizing the auxiliary heat source above the reaction pressure of 218 atm and being preheated by the auxiliary heat source heater 32 to the supercritical heat exchanger 35. The auxiliary heat source 14 is heat-exchanged with the organic material-containing waste solution, the oxidizing agent, the neutralizing agent, and the auxiliary heat source in the preheater 33, and then discharged so that the temperature of the reaction mixture injected into the reactor 34 is 374 ° C or higher. Preheating; d) a step in which the reaction mixture containing the organic matter-containing waste liquid maintains a high flow rate while the organic matter oxidation reaction is carried out while passing through the reactor 34; e) cooling the treated water while preheating the auxiliary heat source introduced from the supercritical heat exchanger (35) after the reaction in the reactor is completed; f) mixing the treated water passing through the supercritical heat exchanger (35) with the quench water in the quench mixer (36) and rapidly cooling it to 300 deg. C or less, and the mixed water discharged from the quench mixer (36) is subcritical. Cooling down to 100 ° C. or lower at 37; g) reducing the pressure of the mixed water passing through the quench mixer 36 to a pressure drop device 38 and a pressure drop valve 39 while maintaining the reactor pressure; h) separating the decompressed treated water into a gas phase and a liquid phase in a gas-liquid separator (41); And i) discharging the gaseous exhaust gas 43 and pressurizing a part of the liquid treatment water to the reactor pressure or higher to continuously inject the liquid into the quench mixer 36 and discharging the remaining liquid treatment water 44. Doing; Characterized in that it comprises a.

As shown in FIG. 1, the organic matter-containing waste liquid 11 is elevated to an operating pressure equal to or higher than the critical pressure (218 atm) of water through the organic-containing waste liquid pump 24, and then heat exchanged in a subcritical heat exchanger 37 to waste heat heater. Or injected into the waste liquid heater 31 to rise to a subcritical temperature at which no inorganic material precipitation occurs. In order to prevent corrosion generated during the preheating of the organic matter-containing waste liquid, an appropriate neutralizing agent is added to the waste liquid and preheated under anoxic conditions.

The neutralizing agent is mixed for the purpose of adjusting the pH of the anticorrosive and the treated water and injected in an amount of more than 1 to 30% by weight based on a theoretical equivalent weight to neutralize the corrosive anions contained in the organic-containing waste solution, and 1 to 80% by weight of the neutralizing agent is added. The mixture is injected into the organic matter-containing waste liquid, and the remainder is preferably injected into the preheat mixer 33. The neutralizing agent is an aqueous solution in which at least one compound selected from the group containing an alkali metal hydroxide and an alkali metal carbonate is dissolved in water, and NaOH, KOH, Na ₂ CO ₃ , and K ₂ CO ₃ are particularly preferable.

The auxiliary heat source 14 is elevated to the operating pressure through the auxiliary heat source pump 23, and then is raised above the supercritical temperature through the auxiliary heat source heater 32 and the supercritical heat exchanger 35 in anoxic conditions, thereby preheating the mixer. It is injected into (33). The auxiliary heat source 14 may be water or a mixture of organic materials and water containing no elements such as metallic cations and elements generating corrosive anions selected from chlorine, fluorine, bromine, sulfur, phosphorus and nitrogen, and the reaction heat is sufficient. It is preferable to use an isopropyl alcohol solution or the like which is fast in decomposition.

The supercritical temperature auxiliary heat source introduced into the preheating mixer 33 of the sedimentation-preventing structure in which the inner wall of the anticorrosive material is installed reacts first with some oxidizing agent 12 to become a high temperature supercritical state. In some cases, the temperature may rise to 600 ° C or higher. In this way, the waste fluid preheated to the subcritical temperature by the auxiliary heat source maintained in the supercritical state in the preheater 33 is mixed with the oxidizing agent 12 and the additional neutralizing agent 13 so that the mixed fluid is temporarily raised to the supercritical temperature. It is then introduced into the reactor (34).

 Since the fluid mixed in the preheater 33 is instantaneously in the supercritical state, the solubility of the inorganic material is drastically reduced, so that the contained inorganic material is precipitated into fine particles. However, the finely deposited inorganic material particles are introduced into the reactor 34 at a high speed at the same time, so that the problem of accumulation in the preheating mixer 33 or the inlet of the reactor 34 is not generated. In the supercritical water, the precipitation of inorganic material, which grows on the wall, causes tube blockage, which is more serious in the form of external heating where the temperature of the reactor wall is higher than the temperature of the fluid. However, if the temperature of the wall surface is lower than the precipitation temperature of the inorganic material, even if the growth starts on the wall surface, the precipitated inorganic material starts to melt again, weakening the adhesion of the inorganic material, and thus the growth of the inorganic material is limited, in the present invention As shown in FIG. 2, the inner wall of the preheater was continuously cooled by some oxidant flowing into the outlet portion of the preheater 33 to prevent the accumulation of inorganic material at the reaction mixture outlet 116. Oxidizers used in the present invention are oxygen, air, gas containing oxygen, hydrogen peroxide aqueous solution, ozone and oxygen containing liquid, the amount of oxidizing agent is the required amount of waste liquid oxidant which is the amount of oxidant required to oxidatively decompose the organic matter of the organic-containing waste liquid and the The amount of auxiliary heat source oxidant required to oxidatively decompose the organic matter contained in the auxiliary heat source is calculated by adding the required amount of auxiliary heat source oxidant, and the amount of each oxidant injected is determined and injected in an amount exceeding 1 to 50% by weight of the respective oxidant required.

When the oxidant flowing into the oxidant inlet 115 near the reaction mixture outlet 116 of the preheater 33 is gas, the water is mixed with the oxidant to inject water into the vicinity of the outlet of the inner wall of the preheater 33 at 374 ° C. Cool to below and at the same time allow the oxidant and water to preheat.

The mixed fluid discharged from the preheater 33 must maintain a supercritical temperature of 374 ° C. or higher. When injected into the reactor 34 at a subcritical temperature, the early stage of the reactor 34 is maintained in a subcritical state, and corrosion occurs and the flow rate is slower than that of the supercritical condition, thereby causing a problem of clogging of the pipe due to precipitation of inorganic materials. In addition, organic decomposition is not smooth, requiring additional reactor residence time and excessive external heating. However, by preheating the reactor preheating of the preheated waste liquid using the preheating mixer 33 using the exothermic reaction of the auxiliary heat source, the preheating mixer is minimized by minimizing the possible corrosion zone of the subcritical condition under aerobic temperature by rapidly increasing the reactor injection temperature from the subcritical temperature to the supercritical temperature. In addition to (33), it is possible to prevent corrosion at the inlet of the reactor 34. Corrosion in the reactor 34 maintained at supercritical temperature is very weak even under aerobic reaction, and the linear velocity of the reaction mixture passing through the reactor is maintained at a rate of 100 cm / s or more due to the rapid flow rate, resulting from inorganic material precipitation. No blockages occur. The treated water discharged at a high supercritical temperature of 450 ° C. or higher after the oxidative decomposition of the organic material is primarily heat exchanged with the auxiliary heat source in the supercritical heat exchanger 35 to increase energy efficiency. However, since the corrosion is increased when the temperature of the treated water after heat exchange under aerobic is reduced to the subcritical region, a supercritical temperature of 374 ° C. or higher must be maintained even after heat exchange in the supercritical heat exchanger 35.

A quench mixer (36) was installed to prevent the precipitation of inorganic materials due to the corrosion caused in the process of aerobic treatment water falling from the supercritical temperature to the subcritical temperature and the decrease in flow rate due to the increase in density due to the temperature drop. The treated water in the high temperature supercritical state discharged from the reactor must be maintained in a supercritical state of 374 ° C. or higher even though it is cooled while being heat exchanged with an auxiliary heat source introduced from the supercritical heat exchanger 35 to prevent a sharp increase in corrosion rate. have. As such, the treated water having a low supercritical temperature discharged from the supercritical heat exchanger 35 is mixed with the treated water and the quench mixer 36 which is cooled to room temperature by the quench water pump 42 and recycled to precipitate corrosion and inorganic substances. It cools to the temperature below 300 degreeC which does not generate | occur | produce. The treated water below 300 ° C. is secondarily exchanged with the organic matter-containing waste liquid 11 through a subcritical heat exchanger 37 to increase energy efficiency and to reduce the discharge of inorganic substances in the treated water. 38), the pressure is reduced within 5 bar at the pressure drop valve 39. The pressure-reduced treated water is discharged to the exhaust gas 43 and part of the treated water 44 via the gas-liquid separator 41, and some of the treated water is driven by the quench water pump 42 to be used as quench water. After rising to the pressure is injected into the quench mixer (36).

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are intended only for understanding the constitution and effects of the present invention and are not intended to limit the scope of the present invention.

Example 1

Analysis of the method and sedimentation of the process developed through the treatment of wastewater containing organic chloride

In the decomposition of chlorinated organic waste liquid containing 10,000 ppm of 2-chlorophenol by supercritical water oxidation method, conventional supercritical water oxidation was carried out under the same conditions using O ₂ as an oxidizing agent and Na ₂ CO ₃ as a neutralizing agent. An experiment was conducted to compare the process and precipitation of the supercritical water oxidation process developed in the present invention.

 As can be seen from Table 1, as a result of the treatment of the wastewater containing chlorinated organic matter by the supercritical water oxidation process developed in the present invention, while the organic decomposition of the conventional supercritical water oxidation process is maintained, the occurrence of corrosion is insignificant and the problem of precipitation of inorganic matters is maintained. You can see that it does not occur.

On the other hand, in the conventional supercritical water oxidation process, it can be seen that corrosion proceeds considerably despite adding neutralizing agent to the waste liquid containing chloride. In particular, due to the precipitation of inorganic material, ΔP, which is the difference between the waste liquid injection pressure and the pressure of the reactor, gradually increased, and then a blockage occurred in an instant. These results indicate that in the conventional supercritical water oxidation process, not only severe corrosion during oxidative decomposition of organic matter-containing waste liquids including corrosive substances and inorganic substances, but also clogging due to precipitation of inorganic substances, which significantly lower their solubility under supercritical conditions, is normal. It is to confirm that driving is difficult.

TABLE 1

Example 2

Corrosion Analysis of Subcritical Preheating Sections of Waste Organic Wastes

The amount of corrosion of the waste liquid heater composed of Inconel-625 was treated to the treated water according to the waste liquid preheating temperature using the chloride organic waste liquid containing 10,000 ppm of 2-chlorophenol, O ₂ as the oxidizing agent, and Na ₂ CO ₃ as the neutralizer. It was measured by the corrosion component contained.

As can be seen in Table 2, it can be seen that the corrosion of Fe and Ni decreases sharply when preheating the chlorinated organic matter-containing waste solution under anoxic conditions without neutralizers rather than without anoxic conditions.

According to the method according to the present invention, the waste liquid containing the corrosive substance and the inorganic substance is injected into the reactor at supercritical temperature using the exothermic reaction of the auxiliary heat source, so that the waste liquid containing the corrosive substance and the inorganic substance is neutralized under anoxic conditions. Preheated to a subcritical temperature at which no mineral precipitation occurs.

On the other hand, the conventional supercritical oxidation method severely corrodes in subcritical preheating sections because the oxidant is pre-mixed with the organic-containing waste solution containing corrosive and inorganic substances in order to obtain the organic decomposition effect in the preheating of the waste liquid. If the neutralizer is not added even if the oxidizing agent is excluded to prevent such corrosion, significant corrosion occurs in the preheating process due to the dissolved oxygen, which is present in a small amount in the waste liquid containing the corrosive and inorganic substances. It can be seen.

TABLE 2

Example 3

Corrosion and Organics Content Analysis of Preheating of Auxiliary Heat Source in Anaerobic Condition

Corrosion and organic content results after anoxic preheating of 6% by volume of isopropyl alcohol (COD _Cr 125,000 ppm) used as auxiliary heat source were analyzed.

As can be seen in Table 3, irrespective of the preheating temperature of the auxiliary heat source, it was confirmed that the corrosion occurred in the anoxic supercritical condition was insignificant, and there was almost no decomposition of organic matter, so that sufficient exothermic reaction occurred in the preheating mixer.

TABLE 3

Example 4

Analysis of Corrosion and Decomposition of Subcritical Temperature and Supercritical Temperature into Reactor with and without Preheating Mixer

The temperature gradient of the reactor according to the reactor injection temperature was analyzed by using chloride organic waste liquid, auxiliary heat source, oxidizing agent and neutralizer containing 10,000 ppm of 2-chlorophenol, and the change of reactor injection temperature with or without preheating mixer Corrosion components and residual organics of treated water were analyzed.

As can be seen from Table 4, when the chlorinated organic matter-containing waste liquid, auxiliary heat source, oxidizing agent and neutralizing agent were injected into the reactor at subcritical temperature, it was confirmed that the subcritical region was maintained at the top of the reactor and injected into the reactor at supercritical temperature. It can be seen that the temperature rise in the reactor is not greater than that. As shown in Table 5, when the preheating mixer was installed and the reactor injection temperature was a supercritical temperature, it was confirmed that the anticorrosive effect and the decomposition of organic matter were excellent.

On the other hand, when the preheating mixer was not installed, organic decomposition was poor and more corrosion proceeded, and clogging occurred after a certain operating time.

That is, when the preheating mixer 33 is not installed, serious inorganic material precipitation occurs in the process of preheating the waste liquid containing the corrosive substance and the inorganic substance to which the neutralizing agent is added or the waste liquid containing many inorganic substances to the supercritical temperature. Therefore, for normal operation, preheat the waste liquid containing corrosive and inorganic substances with neutralizing agent or the waste liquid containing many inorganic substances to the subcritical temperature at which inorganic substances do not occur, and then mix the neutralizing agent and oxidizing agent. It must be injected into the reactor, whereby the top of the reactor is rich in oxidant and kept at subcritical temperature, which not only leads to significant corrosion, but also contains corrosive and inorganic materials that proceed at high flow rates to achieve the desired level of organic decomposition. Increased heating and residence time of waste liquid containing organic matter It has the disadvantage of having to .

TABLE 4

TABLE 5

Example 5

Precipitation Analysis of Inorganic Substances at the Inlet of the Preheat Mixer

After the reaction was carried out using a waste liquid containing 10,000 ppm of 2-chlorophenol, an auxiliary heat source, an oxidizing agent, and a neutralizing agent, the precipitation tendency of the inorganic material at the inlet of the reactor according to the presence of the preheater was analyzed.

As can be seen in Table 6, when the preheating mixer is not installed, clogging due to the precipitation of the inorganic material occurred, whereas the precipitation of the inorganic material did not occur when the preheating mixer was installed. That is, when no preheating mixer is installed, the pre-heating waste solution containing corrosive and inorganic substances containing neutralizing agents or the waste liquid containing many inorganic substances is directly preheated and raised to supercritical temperature, and then the oxidizing agent and neutralizing agent are added to the reactor. However, the solubility of the inorganic material is drastically lowered at the subcritical temperature around 374 ° C., resulting in precipitation of the inorganic material. When neutralizing agents such as Na ₂ CO ₃ are added to prevent corrosion in the preheating process of the chloride organic waste liquid containing 10,000 ppm of 2-chlorophenol, precipitation of inorganic substances occurs at subcritical temperature around 374 ° C. In addition, even when a large amount of inorganic material is present in the waste liquid itself, the problem of precipitation of inorganic material at subcritical temperature around 374 ° C is serious. In addition, even in the process of adding the neutralizing agent to the waste liquid preheated to the supercritical temperature, depending on the type of neutralizing agent causes severe inorganic material precipitation in the neutralizing agent injection pipe, making normal operation difficult. However, when a preheating mixer is installed, the chlorinated organic waste liquid containing 10,000 ppm of 2-chlorophenol added with a neutralizing agent is preheated to a subcritical temperature without precipitation of inorganic substances, and homogeneous or heterogeneous neutralizers are directly transferred to the preheating mixer 33. After the injection, the effect of injecting into the reactor at supercritical temperature while preventing corrosion and precipitation of inorganic materials by using the exothermic reaction of the auxiliary heat source can be confirmed.

TABLE 6

Example 6

Analysis of Release of Inorganic Substances According to Reactor Flow Rate

Chlorinated organic waste, auxiliary heat source, oxidizing agent and neutralizing agent containing 10,000 ppm of 2-chlorophenol were injected into the reactor at supercritical temperature, and the inorganic material released as organic matter was decomposed according to the flow rate of the reactor was measured. As shown in FIG. 3, when the flow rate in the reactor is maintained to be greater than 100 cm / sec, most of the inorganic materials introduced due to the chlorinated organic waste liquid and the neutralizing agent are discharged, and clogging due to precipitation of the inorganic materials in the reactor. It was confirmed that this does not occur.

Waste materials containing organic materials, including corrosive substances and inorganic substances, mixed with supercritical temperatures, auxiliary heat sources, oxidizing agents and neutralizers have a high flow rate in the reactor, thereby preventing precipitation of inorganic substances at high flow rates.

Example 7

Corrosion analysis according to the reaction temperature of the reactor

As a result of the operation using chlorinated organic waste liquid, auxiliary heat source, oxidizing agent and neutralizing agent containing 10,000 ppm of 2-chlorophenol, the corrosion component of treated water was analyzed according to the reaction temperature while maintaining the temperature of the entire section of reactor. It was.

As shown in Table 7, even if the anticorrosive effect to some extent by the neutralizing agent injected into the reactor, if a subcritical temperature section occurs in the reactor under aerobic conditions, it can be confirmed that severe corrosion occurs for all Fe, Ni, Cr and Mo These results show that corrosion occurs intensively in this region if some sections of the reactor are maintained at subcritical temperatures.

TABLE 7

Example 8

Analysis of the Effect of the Quench Mixer for the Cooling Process of Supercritical Temperature Treated Water

Chlorinated organic waste, auxiliary heat source, oxidant and neutralizer containing 10,000 ppm of 2-chlorophenol mixed at supercritical temperature to confirm the effectiveness of the quenching mixer for the supercritical temperature process during cooling. The supercritical heat exchanger 35 is primarily used to prevent corrosion by the treated water during the heat exchange process by treatment water of 450 ° C. or higher, waste liquid and auxiliary heat source after the decomposition of organic matter through the appropriate residence time in (34). Installed a quench mixer (36) with an inner wall of the anticorrosive material in the 300 to 374 ℃ area of the treated water having lowered the treated water to 450 ℃ or more at 374 ℃, and then rapidly lowered the treated water to 300 ℃ or less quenched mixer It was compared with the corrosion result when (36) was not installed.

It was confirmed in Table 8 that the corrosion of Cr and Mo in the subcritical heat exchanger 37 of the treated water was greatly suppressed by the installation of the quench mixer 36.

TABLE 8

Example 9

Analysis of the Effect of the Quench Mixer for Precipitation during Supercritical Temperature Treatment

A quench mixer (36) for preventing corrosion of the treated water and precipitation of inorganic substances in the 300 to 374 ° C region after oxidation using an chlorinated organic matter containing waste of 2-chlorophenol, auxiliary heat source, oxidizing agent and neutralizing agent. The precipitation results of inorganic materials according to the presence or absence of In the absence of the quench mixer 36, clogging occurred in an instant while ΔP, the pressure difference between the pressure of the reactor 34 and the rear end of the quench mixer 36, gradually increased, but the quench mixer 36 according to the present invention was installed. In the cooling process of the water it was confirmed that the problem of precipitation of inorganic matter does not occur.

That is, the quench mixer 36 provided in accordance with the present invention serves to prevent the processing water from being cooled from the supercritical temperature to the subcritical temperature so that the flow rate decreases rapidly due to a large increase in density, thereby preventing clogging due to precipitation of the inorganic material. Done.

TABLE 9

As described above, the present invention has developed a process for preventing clogging due to corrosion and precipitation of inorganic substances in the entire area of the supercritical water oxidative decomposition process of the organic matter-containing waste liquid. In particular, the present invention shows a decomposition rate equivalent to that of organic wastes containing supercritical water using a preliminary supercritical water oxidation method. It is effective in preventing clogging caused by corrosion, and supercritical water oxidation process, which consumes a large amount of energy, is installed to prevent the precipitation of inorganic materials, and supercritical heat exchangers and quenching mixers are installed to prevent corrosion of the treated water and precipitation of inorganic materials. Developed a process that prevents and recovers enough energy. A preheated auxiliary heat source is used to rapidly raise the reactor injection temperature of the organic-containing waste liquid to the supercritical temperature in a preheater equipped with an inner wall of an anticorrosive material to eliminate the corrosive sections of subcritical conditions under aerobic conditions that may form at the reactor inlet. The corrosion of the reactor was prevented, and the precipitation of the inorganic material by the organic matter-containing waste liquid and the neutralizing agent injected into the reactor was prevented by the structure of the preheat mixer. After oxidative decomposition of the organic matter-containing waste liquid in the reactor, the treated water discharged to a high supercritical temperature of 450 ° C. or higher is first lowered to 374 ° C. or higher in a supercritical heat exchanger, and the quenched mixer is finally recycled and injected into the treated water cooled to room temperature. After rapidly lowering the temperature of the treated water to 300 ° C. or less, the secondary water is lowered to 100 ° C. or lower due to heat exchange in a subcritical heat exchanger. In particular, the preheating mixer and the quenching mixer not only prevent the precipitation of the inorganic material, but also have an effect of preventing the serious corrosion occurring in the 300 to 374 ° C region by installing the inner wall of the anticorrosive material.

Claims (18)

A waste liquid heater 31 for preheating the mixture of organic matter-containing waste liquid 11 and the neutralizing agent 13 to subcritical temperature under anoxic conditions; A preheat mixer (33) which allows the waste liquid preheated from the waste liquid heater (31) to be mixed with the pressurized oxidant (12), the neutralizing agent (13) and the auxiliary heat source (14) which is preheated by heat exchange with the treated water of the reactor; A reactor 34 in which the organic matter-containing waste liquid discharged from the preheater 33 is maintained at a flow rate of 100 cm / s or more by an exothermic reaction of the preheated auxiliary heat source, and the organic material oxidation reaction is performed; A supercritical heat exchanger (35) which heat-exchanges the treated water discharged from the reactor (34) to the supercritical temperature to cool the treated water above the supercritical temperature and simultaneously preheats the auxiliary heat source (14); A quench mixer (36) for quenching the treated water by mixing the treated water passing through the supercritical heat exchanger (35) with quenched water; A subcritical heat exchanger (37) which heats the mixed water discharged from the quench mixer (36) and the organic matter-containing waste liquid (11) to further cool the mixed water and simultaneously heat the organic-containing waste liquid (11); A pressure reducing device 38 and a pressure drop valve 39 for reducing the pressure of the mixed water; A gas-liquid separator 41 for separating the reduced pressure of the treated water into a gas phase and a liquid phase; An apparatus for oxidative decomposition of an organic matter-containing waste liquid using a supercritical water oxidation method, characterized by comprising: The method of claim 1, The preheat mixer 33 has a preheat mixer inner wall 117 which is blocked toward the preheat mixer outer wall 118 and the reaction mixture outlet 116 and a portion adjacent to the inlet is communicated with the inside of the preheat mixer; It is provided on the preheat mixer outer wall 118 adjacent to the reaction mixture outlet 116, and the oxidant inlet for entering the preheat mixer through the communication part flowing in the opposite direction to the flow of the reaction mixture between the outer wall and the inner wall of the preheat mixer 115; An auxiliary heat source injection port 114 having a nozzle communicating with an outer wall of the inlet side preheating mixer; A triple pipe which is divided into a neutralizing agent inlet 113, an organic matter-containing waste solution inlet 111, and an oxidant inlet 112 from the center and is provided inside the preheating mixer and extends to a region adjacent to the outlet 116; Oxidative decomposition device of the organic matter-containing waste liquid using a supercritical water oxidation method, characterized in that consisting of. The method of claim 1, Inner wall 117 of the preheat mixer or inner wall of the quench mixer 36 is made of at least one metal selected from the group consisting of titanium, tantalum, iridium, nickel alloys, oxidation of the waste containing organic matter using supercritical water oxidation. Disassembly unit. The method of claim 1, The reactor (34) is an oxidative decomposition apparatus of an organic matter-containing waste liquid using a supercritical water oxidation method, characterized in that the tubular reactor. The method of claim 1, The decompression device 38 is an organic material using supercritical water oxidation, characterized in that the group installed in two or more selected from the group of capillary pressure reducer, orifice pressure reducer, pressure reducing valve, etc. in parallel or in series, or a mixed arrangement in parallel and in series. Oxidative decomposition device of containing waste liquid. a) A part of the neutralizing agent 13 is mixed with the organic matter-containing waste liquid 11, pressurized to at least 218 atmospheres of the reaction pressure in anoxic conditions, and to the temperature below 350 degreeC by the subcritical heat exchanger 37 and the waste liquid heater 31. Preheating and continuously injecting the preheat mixer 33; b) pressurizing the oxidizing agent and the neutralizing agent to the reaction pressure of 218 atmospheres or more and injecting the oxidizing agent inlet 112 and the neutralizing agent inlet 113 installed in the preheating mixer 33, and the remaining part of the oxidant is the preheating mixer ( 33 is continuously injected into the preheating mixer 33 through the oxidant inlet 115 adjacent to the reaction mixture outlet 116 of 33) and flows in the direction opposite to the flow direction of the reaction mixture to flow into the inner wall 117 of the preheating mixer. Mixing the auxiliary heat source with the reaction mixture after the oxidation reaction is initiated; c) Treatment water discharged to the supercritical temperature from the reactor 34 by pressurizing the auxiliary heat source above the reaction pressure of 218 atm and being preheated by the auxiliary heat source heater 32 to the supercritical heat exchanger 35. The auxiliary heat source 14 is heat-exchanged with the organic material-containing waste solution, the oxidizing agent, the neutralizing agent, and the auxiliary heat source in the preheater 33, and then discharged so that the temperature of the reaction mixture injected into the reactor 34 is 374 ° C or higher. Preheating; d) a step in which the reaction mixture containing the organic matter-containing waste liquid maintains a high flow rate while the organic matter oxidation reaction is carried out while passing through the reactor 34; e) cooling the treated water above the supercritical temperature while preheating the auxiliary heat source introduced from the supercritical heat exchanger (35) after the reaction in the reactor is completed; f) mixing the treated water passing through the supercritical heat exchanger (35) with the quench water in the quench mixer (36) and rapidly cooling it to 300 deg. C or less, and the mixed water discharged from the quench mixer (36) is subcritical. Cooling down to 100 ° C. or lower at 37; g) reducing the pressure of the mixed water having passed through the quench mixer 36 to a pressure drop device 38 and a pressure drop valve 39 while maintaining the reactor pressure; h) separating the treated water under reduced pressure into a gas phase and a liquid phase in a gas-liquid separator (41); And i) discharging the gaseous exhaust gas 43 and pressurizing a portion of the liquid treatment water to the reaction pressure or higher to continuously inject the liquid into the quench mixer 36 and discharging the remaining liquid treatment water 44. ; Supercritical water oxidative decomposition method of the organic matter-containing waste liquid comprising a. The method of claim 6, The required amount of oxidant is calculated by adding the required amount of waste liquid oxidant, which is the amount of oxidant required to oxidatively decompose the organic matter of the organic matter-containing waste liquid, and the required amount of auxiliary heat source oxidant, which is the amount of oxidant required to oxidatively decompose the organic matter contained in the auxiliary heat source. Supercritical water oxidative decomposition method of the organic matter-containing waste liquid, characterized in that the injection of 1 to 50% by weight more than the required amount of each oxidant. The method of claim 7, wherein Said oxidant is selected from the group consisting of oxygen, air, gas containing oxygen, ozone, hydrogen peroxide aqueous solution or liquid containing oxygen, the supercritical water oxidative decomposition method of the organic matter-containing waste liquid. The method of claim 6, Supercritical water oxidation of an organic matter-containing waste liquid, characterized in that the internal temperature of the inner wall 117 of the preheat mixer 33 composed of double walls and the temperature of the reaction mixture discharged from the preheat mixer 33 are maintained at 374 ° C. or higher. Decomposition method. The method according to claim 6 or 9, When the oxidant flowing into the oxidant inlet 115 near the reaction mixture outlet 116 of the preheater 33 is gas, the water is mixed with the oxidant and injected into the circumference of the outlet of the inner wall 117 of the preheat mixer 374 A method of supercritical water oxidative decomposition of an organic matter-containing waste liquid, characterized by cooling below 占 폚 and simultaneously oxidizing agent and water. The method of claim 6, The auxiliary heat source (14) is a supercritical water oxidative decomposition method of the organic matter-containing waste liquid, characterized in that the water containing no organic matter and inorganic matter. The method of claim 6, The auxiliary heat source 14 is an organic matter-containing waste liquid, characterized in that it is water or a mixture of organic matter and water that does not contain a component of a metal cation and an element generating a corrosive anion selected from chlorine, fluorine, bromine, sulfur, phosphorus and nitrogen. Supercritical water oxidation method. The method of claim 6, The neutralizing agent is supercritical water oxidative decomposition method of the organic matter-containing waste liquid, characterized in that to inject 1 to 30% by weight more than the weight of the theoretical equivalent to neutralize the corrosive anion contained in the organic waste. The method of claim 13, 1 to 80% by weight of the neutralizer injection amount is mixed and injected into the organic matter-containing waste liquid, the remainder is injected into the preheat mixer (33), supercritical water oxidative decomposition method of the organic matter-containing waste liquid. The method according to claim 13 or 14, The neutralizing agent is a supercritical water oxidative decomposition method of an organic matter-containing waste liquid, characterized in that an aqueous solution in which at least one compound selected from the group comprising an alkali metal hydroxide and an alkali metal carbonate is dissolved in water. The method of claim 6, The linear velocity of the reaction mixture passing through the reactor is supercritical water oxidative decomposition method of an organic matter-containing waste liquid, characterized in that the rate is maintained at 100 cm / s or more. The method according to claim 6 or 16, The method of supercritical water oxidative decomposition of an organic matter-containing waste liquid, characterized in that the temperature of the treated water discharged after the reaction mixture is oxidized in the reactor (34) is maintained at 450 ℃ or more. The method according to claim 6 or 17, And the treated water discharged from the reactor is heat-exchanged with the auxiliary heat source while passing through the supercritical heat exchanger, and cooled to a temperature maintaining at least 374 ° C.

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