Continuous wet catalytic oxidation treatment device and method for high-concentration organic wastewater

Abstract

The invention relates to the technical field of wastewater treatment, and provides a continuous wet catalytic oxidation treatment device and method for high-concentration organic wastewater. The continuous wet catalytic oxidation treatment device provided by the invention comprises a wastewater liquid inlet system, a mixing system, a reaction system and a cooling-backpressure system, and further comprises a gas inlet system. The device provided by the invention can realize continuous wet catalytic oxidation treatment of the high-concentration organic wastewater, is small in occupied area and low in treatment energy consumption, can continuously decompose organic matters and ammonia nitrogen in the high-concentration organic wastewater in one step, greatly reduces the treatment difficulty and cost of the high-concentration organic wastewater, and improves the treatment efficiency of the high-concentration organic wastewater. The problem of industrialization of a wet catalytic oxidation process is solved, and the method has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a device and method for continuous wet catalytic oxidation treatment of high-concentration organic wastewater. Background Art

[0002] High-concentration organic wastewater refers to wastewater with a chemical oxygen demand (COD) ≥ 2000 mg / L, which mainly comes from the chemical, pharmaceutical, food processing, landfill leachate and other industries. It is characterized by complex composition, high toxicity and poor biodegradability, which makes it difficult to treat high-concentration wastewater and difficult to directly degrade it by traditional biological methods.

[0003] At present, the common treatment methods for high-concentration organic wastewater include chemical oxidation treatment (such as Fenton oxidation method), supercritical water oxidation technology, incineration method and physical treatment method, but none of them can reduce high-concentration organic wastewater to the discharge standard in one step or one process. It is usually necessary to combine multiple methods, such as chemical reagent oxidation method + biological method, physical separation method + incineration method, etc. The above treatment methods all have the disadvantages of high energy consumption in the treatment process, large reagent consumption, large equipment footprint, and high treatment cost.

[0004] Wet catalytic oxidation uses an oxidant in the presence of a catalyst to decompose organic matter in wastewater into carbon dioxide, water, and harmless small molecules. Wet catalytic oxidation can be used to treat high-concentration organic wastewater, achieving efficient degradation of organic matter under relatively low process conditions. However, wet catalytic oxidation requires relatively high reaction pressures (1-3 MPa), and currently can only be performed batchwise using kettle reactors. Industrialization of this process has been difficult in this field. Summary of the Invention

[0005] In light of this, the present invention provides a continuous wet catalytic oxidation treatment device and method for high-concentration organic wastewater. This invention addresses the challenges of industrializing the wet catalytic oxidation process, enabling continuous wet catalytic oxidation treatment of high-concentration organic wastewater and significantly reducing the difficulty and cost of treating high-concentration organic wastewater.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A continuous wet catalytic oxidation treatment device for high-concentration organic wastewater, comprising a wastewater inlet system, a mixing system, a reaction system, and a cooling-back pressure system;

[0008] The wastewater inlet system includes a horizontal flow pump;

[0009] The mixing system includes a micro mixer and a preheating coil; the inlet of the micro mixer is connected to the outlet of the advection pump; the outlet of the micro mixer is connected to the inlet of the preheating coil;

[0010] The reaction system includes a reactor; the reactor includes a reactor body and flange covers respectively provided at the upper and lower ends of the reactor body; the reactor body is vertically arranged; a heating bushing is provided on the outer side of the reactor body; the heating bushing is connected to a circulating heater;

[0011] The lower end of the reactor is communicated with the outlet of the preheating coil;

[0012] The temperature reduction-back pressure system includes a cooling coil and a back pressure valve; the inlet of the cooling coil is connected to the upper end of the reactor.

[0013] Preferably, the continuous wet catalytic oxidation treatment device also includes an air intake system, which includes a gas cylinder; the outlet of the gas cylinder is connected to the inlet of the micro mixer, and the pipeline connecting the outlet of the gas cylinder and the inlet of the micro mixer is sequentially provided with a first-level pressure reducing valve, a second-level regulating valve, a gas flow meter and a one-way valve.

[0014] Preferably, the reactor body and the flange covers at the upper and lower ends of the reactor body are made of Hastelloy;

[0015] The flange covers at the upper and lower ends of the reactor body each include a flange cover body and a cylindrical plug arranged on one side of the flange cover body; a filter is arranged at one end of the cylindrical plug away from the flange cover body.

[0016] Preferably, a temperature sensor is provided in the middle section of the reactor body;

[0017] The upper section, middle section and lower section of the reactor body are all provided with sampling ports.

[0018] Preferably, the mixing system further comprises an oil bath device, wherein the micro mixer and the preheating coil are immersed in a constant temperature oil bath of the oil bath device;

[0019] The temperature reduction-back pressure system further comprises a water bath device, into which circulating cooling water flows; the cooling coil is immersed in the circulating cooling water.

[0020] The present invention also provides a method for treating high-concentration organic wastewater using the continuous wet catalytic oxidation treatment device described in the above scheme, comprising the following steps:

[0021] A wet catalytic oxidation catalyst is loaded into a reactor; a liquid oxidant is added to high-concentration organic wastewater to obtain a mixed solution; the mixed solution is transported to a micro-mixer through a liquid inlet system for mixing, then passed into a preheating coil for preheating, and then passed into a reactor for catalytic oxidation reaction to obtain oxidized water; the oxidized water enters a cooling coil for cooling and then is discharged;

[0022] Alternatively, when the continuous wet catalytic oxidation treatment device includes an air intake system, the method includes the following steps: loading a wet catalytic oxidation catalyst into a reactor; conveying high-concentration organic wastewater to a micromixer through a liquid intake system, and simultaneously introducing a gaseous oxidant into the micromixer through the air intake system, wherein the high-concentration organic wastewater and the oxygen-containing gas are mixed in the micromixer to obtain a gas-liquid mixture; the gas-liquid mixture is preheated in a preheating coil and then introduced into a reactor for a catalytic oxidation reaction to obtain oxidized effluent; the oxidized effluent is cooled in a cooling coil and then discharged;

[0023] The COD value of the high-concentration organic wastewater is ≥2000 mg / L.

[0024] Preferably, the components of the high-concentration organic wastewater include: COD 40,000-50,000 mg / L, nitrate 10,000-20,000 mg / L, aldehydes 500-1,000 mg / L, carboxylic acids 30,000-50,000 mg / L, total nitrogen 20,000-30,000 mg / L, ammonia nitrogen 1,000-2,000 mg / L and ammonium ions 6,000-10,000 mg / L.

[0025] Preferably, the feed flow rate of the organic wastewater is 40 to 200 mL / min; the inlet pressure of the oxygen-containing gas is 3 to 6 MPa; and the flow rate of the gaseous oxidant is 2 to 6 L / min.

[0026] Preferably, the preheating temperature is 90-150°C.

[0027] Preferably, the temperature of the catalytic oxidation reaction is 220-280° C., and the pressure is 3-6 MPa.

[0028] The present invention provides a continuous wet catalytic oxidation treatment device for high-concentration organic wastewater, comprising a wastewater inlet system, a mixing system, a reaction system, and a cooling-back pressure system; the wastewater inlet system comprises a horizontal flow pump; the mixing system comprises a micro mixer and a preheating coil; the inlet of the micro mixer is connected to the outlet of the horizontal flow pump; the outlet of the micro mixer is connected to the inlet of the preheating coil; the reaction system comprises a reactor; the reactor comprises a reactor body and flange covers respectively arranged at the upper and lower ends of the reactor body; the reactor body is arranged vertically; a heating bushing is arranged on the outside of the reactor body; the heating bushing is connected to a circulating heater; the lower end of the reactor is connected to the outlet of the coil; the cooling-back pressure system comprises a cooling coil and a back pressure valve; the inlet of the cooling coil is connected to the upper end of the reactor. The device provided by the present invention can continuously pass high-concentration organic wastewater and an oxidant into the reaction system for wet catalytic oxidation, thereby realizing continuous treatment of high-concentration organic wastewater; and the device provided by the present invention can maintain the temperature and pressure of the reactor stable while continuously treating, thereby ensuring efficient wet catalytic oxidation. In summary, the device provided by the present invention solves the problem that when wet catalytic oxidation technology is used to decompose high-concentration organic wastewater, it can only be tested in small batches due to the high temperature and high pressure reaction conditions and cannot be industrialized. In addition, the equipment occupies a small area and has low processing energy consumption.

[0029] The present invention also provides a method for treating high-concentration organic wastewater using the continuous wet catalytic oxidation treatment device described in the above scheme. The method provided by the present invention realizes continuous wet catalytic oxidation treatment of high-concentration organic wastewater, and has low reagent consumption and low treatment energy consumption. It can continuously decompose and treat organic matter and ammonia nitrogen in high-concentration organic wastewater in one step, greatly reducing the difficulty and cost of treating high-concentration organic wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of the continuous wet catalytic oxidation treatment device for high-concentration organic wastewater provided by the present invention; wherein: 1- horizontal flow pump, 2- gas cylinder, 3- first-stage pressure reducing valve, 4- second-stage regulating valve, 5- gas flow meter, 6- one-way valve, 7- micro mixer, 8- preheating coil, 9- oil bath device, 10- reactor, 11- sampling port, 12- circulating heater, 13- cooling coil, 14- water bath device, 15- back pressure valve, 16- wastewater container, 17- water production container. DETAILED DESCRIPTION

[0031] The present invention provides a continuous wet catalytic oxidation treatment device for high-concentration organic wastewater, comprising a wastewater inlet system, a mixing system, a reaction system, and a cooling-back pressure system;

[0032] The wastewater inlet system includes a horizontal flow pump 1;

[0033] The mixing system includes a micro mixer 7 and a preheating coil 8; the inlet of the micro mixer 7 is connected to the outlet of the horizontal flow pump 1; the outlet of the micro mixer 7 is connected to the inlet of the preheating coil 8;

[0034] The reaction system includes a reactor 10; the reactor 10 includes a reactor body and flange covers respectively provided at the upper and lower ends of the reactor body; the reactor body is vertically arranged; a heating bushing is provided on the outer side of the reactor body; the heating bushing is connected to a circulating heater 12;

[0035] The lower end of the reactor 10 is connected to the outlet of the preheating coil 8;

[0036] The temperature reduction-back pressure system includes a cooling coil 13 and a back pressure valve 15 ; the inlet of the cooling coil 13 is connected to the upper end of the reactor 10 .

[0037] In the present invention, the structural diagram of the continuous wet catalytic oxidation treatment device for high-concentration organic wastewater is as follows Figure 1 As shown below. Figure 1 Provide detailed explanation.

[0038] The continuous wet catalytic oxidation treatment device provided by the present invention includes a wastewater inlet system, which includes a horizontal flow pump 1, and the horizontal flow pump 1 is preferably a constant pressure horizontal flow pump; the flow rate adjustment range of the constant pressure horizontal flow pump is preferably 0 to 200 mL / min, and the inlet pressure adjustment range is preferably 0 to 10 MPa; the inlet of the horizontal flow pump 1 is preferably connected to the wastewater container 16, and the outlet is connected to the micro mixer 7; in a specific embodiment of the present invention, the outlet of the horizontal flow pump 1 is preferably connected to the micro mixer 7 through a stainless steel pipe, and the wall thickness of the stainless steel pipe is preferably 3 mm.

[0039] The continuous wet catalytic oxidation treatment device provided by the present invention preferably also includes an air intake system, which preferably includes a gas cylinder 2; the outlet of the gas cylinder 2 is preferably connected to the inlet of the micromixer 7, specifically through a stainless steel pipe, and the pipeline connecting the outlet of the gas cylinder 2 and the inlet of the micromixer 7 is preferably provided with a first-level pressure reducing valve 3, a second-level regulating valve 4, a gas flow meter 5 and a one-way valve 6 in sequence; the one-way valve is preferably a stainless steel one-way valve; the pressure adjustment range of the first-level pressure reducing valve 3 is preferably 0 to 10 MPa, and the pressure adjustment range of the second-level regulating valve 4 is preferably 0 to 5 MPa; in a specific embodiment of the present invention, the first-level pressure reducing valve 3 is arranged at the outlet of the gas cylinder, the first-level pressure reducing valve 3 is connected to the second-level regulating valve 4 through a stainless steel pipe with a wall thickness of 6 mm, the second-level regulating valve 4 is further connected to the gas flow meter 5 through a stainless steel pipe with a wall thickness of 3 mm, the gas flow meter 5 is connected to the one-way valve 6 through a stainless steel pipe with a wall thickness of 3 mm, and the one-way valve 6 is connected to the micromixer 7 through a stainless steel pipe with a wall thickness of 3 mm.

[0040] The continuous wet catalytic oxidation treatment device provided by the present invention includes a mixing system, which includes a micromixer 7 and a preheating coil 8; the inlet of the micromixer 7 is respectively connected to the outlet of the horizontal flow pump 1 and the outlet of the gas cylinder 2, and the specific connection method is not repeated here; the outlet of the micromixer 7 is connected to the inlet of the preheating coil 8; the present invention has no special requirements for the micromixer 7, and a method familiar to those skilled in the art can be used; the length of the preheating coil 8 is preferably 3m, and the inner diameter is preferably 3mm; the preheating coil 8 is preferably a stainless steel coil; the outlet of the preheating coil 8 is connected to the bottom of the reactor 10.

[0041] In the present invention, the mixing system preferably further comprises an oil bath device 9, wherein the micro mixer 7 and the preheating coil 8 are immersed in a constant temperature oil bath of the oil bath device 9; the temperature adjustment range of the oil bath device 9 is preferably 25 to 200°C.

[0042] The continuous wet catalytic oxidation treatment device provided by the present invention includes a reaction system, which includes a reactor 10, and the reactor 10 includes a reactor body and flange covers respectively arranged at the upper and lower ends of the reactor body; the reactor body is vertically arranged, specifically a vertically arranged cylindrical tube. In a specific embodiment of the present invention, the reactor body is vertically installed by welding; the material of the reactor body and the flange covers at the upper and lower ends of the reactor body are preferably Hastelloy; the wall thickness of the reactor body is preferably 20 mm, the diameter is preferably 100 mm, and the length is preferably 1000 mm; the flange covers at the upper and lower ends of the reactor body preferably include a flange cover body and a cylindrical plug arranged on one side of the flange cover body; the end of the cylindrical plug away from the flange cover body is preferably provided with a filter screen; the mesh number of the filter screen is preferably 100 meshes; the filter screen can intercept the catalyst filled in the reactor body to prevent the catalyst from clogging the inlet of the reactor. The wall thickness of the flange cover body is preferably 20 mm; the diameter of the cylindrical hollow plug is preferably 2 mm smaller than the inner diameter of the reactor body, and the length of the hollow plug is preferably 40 mm; the flange covers at the upper and lower ends of the reactor body are preferably connected and fixed to the reactor body by bolts; each flange cover is preferably connected to the reactor body by 8 bolts, the specification of the bolts is preferably M20, and the 8 bolts are preferably evenly distributed on the outside of the flange cover; the flange covers at the upper and lower ends of the reactor and the reactor body are preferably sealed with a stainless steel high-temperature resistant sealing ring. In a specific embodiment of the present invention, in the flange covers at the upper and lower ends of the reactor 10, a stainless steel pipe is welded at the center of the flange cover body, and the wall thickness of the stainless steel pipe is preferably 6 mm; the stainless steel pipe welded to the flange cover at the lower end of the reactor 10 serves as the inlet of the reactor 10 and is connected to the outlet of the preheating coil, and the stainless steel pipe welded to the flange cover at the upper end of the reactor 10 serves as the outlet of the reactor 10 and is connected to the cooling coil 13.

[0043] In the present invention, the middle section of the reactor body is preferably provided with a temperature sensor; the temperature sensor is preferably installed by sealing welding; the upper section, middle section and lower section of the reactor body are preferably provided with sampling ports 11; in a specific embodiment of the present invention, the reactor body is opened at 300mm, 600mm and 900mm from top to bottom, and DN6 stainless steel ball valves are sealed and welded to be installed as sampling ports.

[0044] In the present invention, a heating sleeve is provided on the outside of the reactor body; the heating sleeve is a sealing sleeve and completely covers the reactor body; the upper and lower ends of the heating sleeve are preferably provided with openings, and the openings are connected to the circulation heating machine 12; the circulation heating machine 12 is preferably an oil bath circulation heating machine; the circulation heating machine 12 circulates hot oil into the heating sleeve to control the temperature of the reactor body; the heating temperature range of the circulation heating machine 12 is preferably 25 to 300°C.

[0045] The continuous wet catalytic oxidation treatment device provided by the present invention includes a cooling-back pressure system, and the cooling-back pressure system includes a cooling coil 13 and a back pressure valve 15; the inlet of the cooling coil 13 is connected to the upper end of the reactor 10, and the specific connection method is not repeated here. The length of the cooling coil 13 is preferably 3 mm, and the wall thickness is preferably 6 mm; the cooling-back pressure system preferably also includes a water bath device 14, and circulating cooling water is preferably passed into the water bath device 14; the cooling coil 13 is preferably immersed in the circulating cooling water. The back pressure valve 15 is preferably installed at the tail end of the cooling coil 13; the back pressure valve 15 is a back pressure valve with a pressure gauge; the pressure adjustment range of the back pressure valve 15 is 0 to 10 MPa; the outlet end of the back pressure valve 15 is preferably connected to a stainless steel pipe, and the outlet end of the stainless steel pipe is placed in a water production container 17 for receiving treated water production; the length of the stainless steel pipe is preferably 1 m, and the wall thickness is preferably 6 mm.

[0046] The present invention also provides a method for treating high-concentration organic wastewater using the continuous wet catalytic oxidation treatment device described in the above scheme. In the present invention, according to the type of oxidant used, the method is divided into method one and method two, which are described in detail below.

[0047] In the present invention, when the oxidant used is a gaseous oxidant, the method is method one, and the device used in the continuous wet catalytic oxidation treatment device includes an air intake system; the method one includes the following steps: loading a wet catalytic oxidation catalyst into a reactor 10; transporting high-concentration organic wastewater to a micromixer 7 through a liquid intake system, and at the same time, passing a gaseous oxidant into the micromixer 7 through an air intake system, and mixing the high-concentration organic wastewater and the oxygen-containing gas in the micromixer 7 to obtain a gas-liquid mixture; the gas-liquid mixture is passed into a preheating coil 8 for preheating and then passed into the reactor 10 for a catalytic oxidation reaction to obtain oxidized effluent; the oxidized effluent enters a cooling coil 13 for cooling and then is discharged.

[0048] In the present invention, the active component of the wet catalytic oxidation catalyst is preferably a precious metal; the wet catalytic oxidation catalyst is preferably a spherical catalyst, and the diameter of the spherical catalyst is preferably 1 to 5 mm, specifically 1 mm, 3 mm or 5 mm. The present invention has no special requirements on the source of the wet catalytic oxidation catalyst, and it can be one well known to those skilled in the art, specifically one or more of a copper-based oxide catalyst, a platinum-based catalyst and an iron-carbon catalyst. In the present invention, the method for loading the wet catalytic oxidation catalyst is preferably: after removing the upper flange cover of the reactor 10, the wet oxidation catalyst is put into the reactor body and loaded to 40 mm from the upper edge of the reactor body, and then the upper flange cover is covered, and the bolts are tightened after aligning the stainless steel sealing gasket.

[0049] In the present invention, the COD value of the high-concentration organic wastewater is ≥2000 mg / L. Specifically, the components of the high-concentration organic wastewater preferably include: COD 40000-50000 mg / L, nitrate 10000-20000 mg / L, aldehydes 500-1000 mg / L, carboxylic acids 30000-50000 mg / L, total nitrogen 20000-30000 mg / L, ammonia nitrogen 1000-2000 mg / L, and ammonium ions 6000-10000 mg / L.

[0050] In the present invention, the feed flow rate of the high-concentration organic wastewater is preferably 40 to 200 mL / min, specifically 40 mL / min, 50 mL / min, 100 mL / min, 150 mL / min or 200 mL / min.

[0051] In a specific embodiment of the present invention, the high-concentration organic wastewater is stored in a wastewater container 16 , and is transported to the micro-mixer 7 by a horizontal flow pump 1 .

[0052] In the present invention, the gaseous oxidant is preferably an oxygen-containing gas, specifically an oxygen-containing mixed gas or pure oxygen, and the purity of the pure oxygen is preferably above 99%; the inlet pressure of the oxygen-containing gas is 3 to 6 MPa; the flow rate of the oxygen-containing gas is preferably 2 to 6 L / min; the oxygen-containing gas is stored in a gas cylinder 2.

[0053] In the present invention, the high-concentration organic wastewater and the gaseous oxidant are mixed in the micro-mixer 7, and the gaseous oxidant forms micro-nano bubbles in the wastewater, thereby increasing the gas-liquid mixing efficiency and contact time.

[0054] In the present invention, the preheating temperature is preferably 90-150° C.; the micro mixer 7 and the preheating coil 8 are both immersed in a constant temperature oil bath of an oil bath device 9; and the preheated gas-liquid mixture is introduced into a reactor 10 for catalytic oxidation reaction.

[0055] In the present invention, the temperature of the catalytic oxidation reaction is preferably 220-280°C, specifically 240°C, 260°C or 280°C, and the pressure is preferably 3-6MPa, specifically 4MPa or 4.5MPa; in a specific embodiment of the present invention, the back pressure valve 15 is opened during the feeding process and the sampling valve of the reactor 10 is closed; preferably, when liquid is discharged from the outlet of the back pressure valve 15, the circulating heater 12 is turned on, the temperature of the reactor 10 is set to 220-280°C, and the back pressure valve 15 is gradually adjusted at the same time to adjust the system pressure to 3-6MPa. After the reaction temperature and pressure are stable, the new wastewater replaces all the wastewater in the reactor 10 (about 15-25 minutes), and then the produced water is collected in the produced water container 17.

[0056] In the present invention, when the oxidant used is a liquid oxidant, the method is method 2, and the continuous wet catalytic oxidation treatment device used does not include an air intake system, or includes an air intake system but the air intake system is closed; the method 2 includes the following steps:

[0057] A wet catalytic oxidation catalyst is loaded into the reactor 10; a liquid oxidant is added to high-concentration organic wastewater to obtain a mixed liquid; the mixed liquid is transported to the micro-mixer 7 through the liquid inlet system for mixing, then passed into the preheating coil 8 for preheating, and then passed into the reactor 10 for a catalytic oxidation reaction to obtain oxidized water; the oxidized water enters the cooling coil 13 for cooling and then is discharged.

[0058] In the present invention, the indicators and methods for high-concentration organic wastewater are consistent and will not be repeated here.

[0059] In the present invention, the liquid oxidant is preferably hydrogen peroxide. Calculated based on the amount of oxygen, the molar amount of the hydrogen peroxide is preferably twice the COD in the high-concentration organic wastewater.

[0060] In the present invention, the gaseous oxidant does not need to be introduced in the method 2, and other conditions are the same as those in the method 1, which will not be described in detail here.

[0061] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0062] The catalyzer adopted in the following examples is all spherical platinum-based catalyst, and the carrier of described platinum-based catalyst is γ-Al o bead, active ingredient is the elemental platinum that is loaded on γ-Al o bead surface, and the weight of elemental platinum is γ-Al o bead weight 1wt%.The preparation method of platinum-based catalyst is as follows: by γ-Al o bead is immersed in platinum precursor solution (chloroplatinic acid, platinum content is wherein γ-Al o bead weight 1%) in, make platinum precursor uniformly adsorbed on γ-Al o bead surface, with the γ-Al after impregnation o bead dry at 80 ℃ of temperature, after thorough drying, in muffle furnace, carry out roasting, be warming up to 400 ℃ with the speed of 2 ℃ / min, keep 2h, then naturally cool to normal temperature, obtain platinum-based catalyst.By control γ-Al o the diameter of bead, obtain respectively the platinum-based catalyst that diameter is 5mm and 1mm.

[0063] Example 1

[0064] The wet catalytic oxidation catalyst used in this embodiment is a platinum-based catalyst with a diameter of 5 mm.

[0065] Take the raw wastewater (the components of the wastewater are: COD 50000 mg / L, nitrate 10000 mg / L, aldehydes 1000 mg / L, carboxylic acids 30000 mg / L, total nitrogen 30000 mg / L, ammonia nitrogen 2000 mg / L, ammonium ions 10000 mg / L), add an oxidant (oxidant: hydrogen peroxide) with an oxygen content twice the COD equivalent of the raw wastewater into the raw wastewater, stir and mix the raw wastewater and the oxidant, place them at the liquid inlet of the feeding system, open the back pressure valve 15, close the sampling valve 11, open the liquid inlet system, and adjust the constant pressure. The liquid inlet speed of the horizontal flow pump is 60 mL / min, and the constant temperature oil bath temperature of the oil bath device 9 is adjusted to 150°C. The mixed liquid of the raw wastewater and the oxidant is transported to the micro mixer 7 through the liquid inlet system for mixing, and then passed into the preheating coil 8 for preheating, and then passed into the reactor 10. After the liquid is discharged from the outlet of the back pressure valve 15, the circulation heater 10 is opened to adjust the temperature to 240°C, and the pressure is adjusted to 4 MPa through the back pressure valve 15. After the reaction temperature and pressure are stable, the new wastewater replaces all the wastewater in the reactor 10 (about 25 minutes) and then begins to collect the produced water.

[0066] The experimental results show that compared with the raw wastewater, the COD removal rate of the produced water is 73.34%, the nitrate removal rate is 40.83%, the aldehyde removal rate is 90.77%, the carboxylic acid removal rate is 96.75%, the total nitrogen removal rate is 25.00%, the ammonia nitrogen removal rate is 18.45%, and the ammonium ion removal rate is 14.86%.

[0067] Example 2

[0068] The wet catalytic oxidation catalyst used in this embodiment is a platinum-based catalyst with a diameter of 5 mm.

[0069] Take the raw wastewater (wastewater components are: COD50000mg / L, nitrate 10000mg / L, aldehydes 1000mg / L, carboxylic acids 30000mg / L, total nitrogen 30000mg / L, ammonia nitrogen 2000mg / L, ammonium ion 10000mg / L), place it at the liquid inlet of the feeding system, open the back pressure valve 15, close the sampling valve 11, open the liquid inlet system, adjust the liquid inlet speed of the constant pressure horizontal flow pump to 40mL / min, open the regulating valve of gas cylinder 2, adjust the inlet pressure to 4.5MPa, the gas flow rate to 2L / min, and the wastewater is discharged from the liquid inlet system. All of the wastewater is introduced into the micro-mixer 7, and oxygen (purity of 99%) is introduced into the micro-mixer 7 through the air intake system. Micro-nano bubbles are formed in the wastewater by mixing oxygen or pure oxygen. The constant temperature oil bath temperature of the oil bath device 9 is adjusted to 150°C. The liquid discharged from the micro-mixer 7 is introduced into the preheating coil 8 for preheating, and then introduced into the reactor 10. After the liquid is discharged from the outlet of the back pressure valve 15, the circulation heater 10 is opened to adjust the temperature to 260°C, and the pressure is adjusted to 4MPa through the back pressure valve. After the reaction temperature and pressure are stable, the new wastewater replaces all the wastewater in the reactor 10 (about 25 minutes) and then the produced water is collected.

[0070] The experimental results show that compared with the raw wastewater, the COD removal rate of the produced water is 71.52%, the nitrate removal rate is 98.05%, the aldehyde removal rate is 78.93%, the carboxylic acid removal rate is 98.81%, the total nitrogen removal rate is 59.81%, the ammonia nitrogen removal rate is 45.98%, and the ammonium ion removal rate is 55.03%.

[0071] Example 3

[0072] The 5 mm diameter platinum-based catalyst loaded in the reaction system was replaced with an equal volume of 1 mm diameter platinum-based catalyst.

[0073] Take the raw wastewater (wastewater components are: COD50000mg / L, nitrate 10000mg / L, aldehydes 1000mg / L, carboxylic acids 30000mg / L, total nitrogen 30000mg / L, ammonia nitrogen 2000mg / L, ammonium ion 10000mg / L), place it at the liquid inlet of the feeding system, open the back pressure valve 15, close the sampling valve 11, open the feeding system, adjust the liquid inlet speed of the constant pressure horizontal flow pump to 100ml / min, open the regulating valve of gas cylinder 2, adjust the inlet pressure to 5.0MPa, and the gas flow rate to 4L / min; the wastewater is discharged from the liquid inlet system The mixture is introduced into the micro-mixer 7, and oxygen (purity of 99%) is introduced into the micro-mixer 7 through the air intake system. Micro-nano bubbles are formed in the wastewater by mixing oxygen or pure oxygen. The constant temperature oil bath temperature of the oil bath device 9 is adjusted to 150°C. The liquid discharged from the micro-mixer 7 is introduced into the preheating coil 8 for preheating, and then introduced into the reactor 10. After the liquid is discharged from the outlet of the back pressure valve 15, the circulation heater 12 is opened to adjust the temperature to 280°C. The pressure is adjusted to 4.5 MPa through the back pressure valve 15. After the reaction temperature and pressure are stable, the wastewater in the reactor 10 is completely replaced by the new wastewater (about 15 minutes) and then the produced water is collected.

[0074] The experimental results show that compared with the raw wastewater, the COD removal rate of the produced water is 90.40%, the nitrate removal rate is 98.65%, the aldehyde removal rate is 83.53%, the carboxylic acid removal rate is 99.06%, the total nitrogen removal rate is 65.74%, the ammonia nitrogen removal rate is 55.49%, and the ammonium ion removal rate is 70.18%.

[0075] Comparative Example 1 Intermittent kettle experiment

[0076] A 300 mL autoclave made of Hastelloy was used and filled with the same pellet catalyst as in Example 1, with a filling volume of 10 mL.

[0077] High-concentration organic wastewater (COD 50,000 mg / L, nitrate 10,000 mg / L, aldehydes 1,000 mg / L, carboxylic acids 30,000 mg / L, total nitrogen 30,000 mg / L, ammonia nitrogen 2,000 mg / L, ammonium ions 10,000 mg / L) is placed in a reactor, oxygen (purity 99%) is introduced, and the reactor is sealed. The pressure in the reactor is 4 MPa, and the temperature is raised to 240°C. After the reaction is activated, the heating is turned off. After cooling for 1 hour, the vent valve is opened to discharge carbon dioxide and nitrogen to obtain treated wastewater. After the reaction is activated, the pressure changes in the range of 4 to 6 MPa and the temperature changes in the range of 240 to 280°C. Although further heating is not required for subsequent reactions, the reaction pressure and temperature are difficult to maintain and are prone to drastic changes in a short period of time.

[0078] The experimental results show that compared with the raw wastewater, the COD removal rate of the treated wastewater is 85.71%, the nitrate removal rate is 80.10%, the aldehyde removal rate is 68.52%, the carboxylic acid removal rate is 87.83%, the total nitrogen removal rate is 57.05%, the ammonia nitrogen removal rate is 41.33%, and the ammonium ion removal rate is 64.58%.

[0079] Compared with the present invention, traditional wet catalytic oxidation is carried out in a kettle-type high-pressure reactor, which has the problems of difficult reaction control, high safety risks, long reaction time, rapid catalyst wear and consumption, and inability to scale up the process. The device and method provided by the present invention successfully solve the problem that the traditional wet catalytic oxidation process cannot be scaled up, and achieve the goals of precise reaction control, good safety, short reaction time, significant reduction in catalyst wear and consumption, and parallel scale-up of the process and device.

[0080] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A continuous wet catalytic oxidation treatment device for high-concentration organic wastewater, characterized in that: Including wastewater inlet system, mixing system, reaction system and cooling-back pressure system; The wastewater inlet system includes a horizontal flow pump; The mixing system includes a micro mixer and a preheating coil; the inlet of the micro mixer is connected to the outlet of the advection pump; the outlet of the micro mixer is connected to the inlet of the preheating coil; The reaction system includes a reactor; the reactor includes a reactor body and flange covers respectively provided at the upper and lower ends of the reactor body; the reactor body is vertically arranged; a heating sleeve is provided on the outer side of the reactor body; the heating sleeve is connected to a circulating heater; the lower end of the reactor is connected to the outlet of the preheating coil; The temperature reduction-back pressure system includes a cooling coil and a back pressure valve; the inlet of the cooling coil is connected to the upper end of the reactor.

2. The continuous wet catalytic oxidation treatment device according to claim 1, characterized in that: The continuous wet catalytic oxidation treatment device also includes an air intake system, which includes a gas cylinder; the outlet of the gas cylinder is connected to the inlet of the micro mixer, and a first-level pressure reducing valve, a second-level regulating valve, a gas flow meter and a one-way valve are sequentially arranged on the pipeline connecting the outlet of the gas cylinder and the inlet of the micro mixer.

3. The continuous wet catalytic oxidation treatment device according to claim 1 or 2, characterized in that: The reactor body and the flange covers at the upper and lower ends of the reactor body are made of Hastelloy; The flange covers at the upper and lower ends of the reactor body each include a flange cover body and a cylindrical plug arranged on one side of the flange cover body; a filter is arranged at one end of the cylindrical plug away from the flange cover body.

4. The continuous wet catalytic oxidation treatment device according to claim 1 or 2, characterized in that: A temperature sensor is provided in the middle section of the reactor body; The upper section, middle section and lower section of the reactor body are all provided with sampling ports.

5. The continuous wet catalytic oxidation treatment device according to claim 1 or 2, characterized in that: The mixing system further comprises an oil bath device, wherein the micro mixer and the preheating coil are immersed in a constant temperature oil bath of the oil bath device; The temperature reduction-back pressure system further comprises a water bath device, into which circulating cooling water flows; the cooling coil is immersed in the circulating cooling water.

6. A method for treating high-concentration organic wastewater using the continuous wet catalytic oxidation treatment device according to any one of claims 1 to 5, characterized in that: The following steps are involved: A wet catalytic oxidation catalyst is loaded into a reactor; a liquid oxidant is added to high-concentration organic wastewater to obtain a mixed solution; the mixed solution is transported to a micro-mixer through a liquid inlet system for mixing, then passed into a preheating coil for preheating, and then passed into a reactor for catalytic oxidation reaction to obtain oxidized water; the oxidized water enters a cooling coil for cooling and then is discharged; Alternatively, when the continuous wet catalytic oxidation treatment device includes an air intake system, the method includes the following steps: loading a wet catalytic oxidation catalyst into a reactor; conveying high-concentration organic wastewater to a micromixer through a liquid intake system, and simultaneously introducing a gaseous oxidant into the micromixer through the air intake system, wherein the high-concentration organic wastewater and the oxygen-containing gas are mixed in the micromixer to obtain a gas-liquid mixture; the gas-liquid mixture is preheated in a preheating coil and then introduced into a reactor for a catalytic oxidation reaction to obtain oxidized effluent; the oxidized effluent is cooled in a cooling coil and then discharged; The COD value of the high-concentration organic wastewater is ≥2000 mg / L.

7. The method according to claim 6, characterized in that The components of the high-concentration organic wastewater include: COD 40,000-50,000 mg / L, nitrate 10,000-20,000 mg / L, aldehydes 500-1,000 mg / L, carboxylic acids 30,000-50,000 mg / L, total nitrogen 20,000-30,000 mg / L, ammonia nitrogen 1,000-2,000 mg / L and ammonium ions 6,000-10,000 mg / L.

8. The method according to claim 6, characterized in that The feed flow rate of the organic wastewater is 40 to 200 mL / min; the inlet pressure of the oxygen-containing gas is 3 to 6 MPa; and the flow rate of the gaseous oxidant is 2 to 6 L / min.

9. The method according to claim 6, characterized in that The preheating temperature is 90-150°C.

10. The method according to claim 6, characterized in that The temperature of the catalytic oxidation reaction is 220-280° C., and the pressure is 3-6 MPa.

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