System and method for treating organic sewage by using special throttling structure

Abstract

The invention discloses a system and a method for treating organic sewage by utilizing a special throttling structure, and the method is an advanced oxidation technology for efficiently degrading the organic sewage by utilizing hydroxyl radicals generated by the special throttling structure. The system comprises an organic sewage primary filtering device, a pressurizing variable frequency pump, a heater, an air nanobubble exposure device and a special throttling structure oxidation decontamination link, supercritical oxidation reaction mainly occurs in the special throttling structure, and system waste heat is secondarily utilized by a waste heat recovery device in a final additional link. The device realizes efficient decontamination of organic sewage, is high in practicability and relatively low in cost, and can meet the requirements of energy conservation and emission reduction.

Description

Technical Field

[0001] The invention relates to the technical field of organic wastewater treatment, to supercritical water reaction and energy cascade utilization, and in particular to a system and method for treating organic wastewater using a special throttling structure. Background Art

[0002] Traditional organic wastewater treatment methods, such as activated sludge method and biofilm method, can remove organic matter and microorganisms in wastewater to a certain extent, but their treatment efficiency is relatively low and they require a long treatment time and high operating costs. Summary of the invention

[0003] Therefore, the present invention aims to provide a system and method for treating organic sewage using a special throttling structure, so as to solve the problem of low efficiency of organic sewage treatment in the prior art.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A system for treating organic sewage using a special throttling structure, comprising a pressurizing device, a heating device, an air nano bubble exposure device and a special throttling structure;

[0006] The pressurizing device is used to pressurize the organic sewage, the heating device is used to heat the organic sewage, and the air nanobubble exposure device is used to increase the dissolved oxygen content in the organic sewage;

[0007] The special throttling structure is a device with a pressure drop function. The organic sewage that has been pressurized, heated and has an increased dissolved oxygen content flows through the special throttling structure for oxidation and decontamination.

[0008] The present invention adopts a special throttling structure and increases the dissolved oxygen in the organic sewage through an air nano bubble exposure device to increase the reaction efficiency. The product has environmentally friendly characteristics and can achieve green, efficient and stable pollution removal.

[0009] In one embodiment, the order of the pressurizing device, the temperature increasing device and the air nanobubble exposure device is arbitrary.

[0010] In one embodiment, the pressurizing device pressurizes the organic sewage to 20-50 MPa, the heating device heats the organic sewage to 300-700° C., and the air nanobubble exposure device increases the dissolved oxygen content in the organic sewage to 50%-80%.

[0011] In one embodiment, the special throttling structure is a device such as a Tesla valve, an orifice plate or a Venturi tube that has a sudden pressure drop phenomenon. Specifically, when the fluid passes through the hole of the orifice plate, the area decreases and the flow rate increases, causing the pressure to drop suddenly. The greater the pressure and the thicker the orifice plate, the higher the pollution removal efficiency. The Venturi tube has a neck, and the flow rate increases and the pressure drops suddenly at the neck. It has the characteristics of simple structure and low energy consumption. The Tesla valve uses its reverse conduction to generate a pressure difference when the fluid collides. A large flow rate and high speed flow passes through the lower side, forming a low-pressure area on the upper side, and the fluid precipitates oxygen, causing supercritical water oxidation and other reactions. The oxidation efficiency is high and the structure is simple. The above components can all use special structures to cause organic wastewater to undergo supercritical water oxidation and other reactions. There are no mechanical components such as valves, so there is no need for adjustment.

[0012] In one embodiment, the system further comprises: a primary filtration device;

[0013] The primary filtering device is used to filter the organic sewage before the pressurizing device, the heating device and the air nano bubble exposure device.

[0014] Specifically, the present invention uses a primary filtering device to filter the organic sewage, which can be achieved by the following means: passing the organic sewage through an inclined or vertically placed grid to remove larger suspended matter, floating matter, fiber matter and solid particulate matter in the wastewater, thereby ensuring the normal operation of subsequent treatment equipment or structures and reducing the burden of subsequent treatment. Therefore, if the organic sewage has been initially filtered and there is no solid sediment in it, this step and device can be omitted.

[0015] In one embodiment, the system further comprises: a waste heat recovery device;

[0016] The waste heat recovery device is arranged at the outlet position of the special throttling structure, and the liquid material containing liquid water is heat recovered.

[0017] Furthermore, the waste heat recovery device is a heat exchanger, one inlet of which is connected to a pressure reducing valve, the other inlet is connected to cold water, one outlet discharges the organic sewage treatment product after heat exchange, and the other outlet is connected to the user side. The purified organic sewage passes through the sewage content detection device and then enters the pressure reducing valve. The organic sewage treatment product after pressure reduction by the pressure reducing valve is sent to the inlet at one end of the heat exchanger; cold water is sent to the inlet at the other end of the heat exchanger, and the organic sewage treatment product exchanges heat with cold water in the heat exchanger. The organic sewage treatment product after heat exchange is discharged at one outlet, and the other outlet supplies the water after heat exchange to heat users as domestic water or for low-temperature heating.

[0018] In one embodiment, the pressurizing device is a pressurizing pump, the inlet of which is connected to the organic sewage, and the outlet of which is connected to the flow control valve.

[0019] In one embodiment, an organic wastewater content detection device is provided at the inlet and outlet of the special throttling structure to detect the pollution removal efficiency of the throttling structure, and the oxygenation amount of the air nanobubble exposure device is controlled according to the detection result. If the organic wastewater content at the outlet is higher than the set value, the oxygenation amount is increased to adjust the reaction efficiency.

[0020] In one embodiment, the outlet of the special throttling structure is connected back to the air nanobubble exposure device, and the treatment product is a liquid mixed with bubbles.

[0021] The present invention also provides a treatment method based on the system for treating organic sewage using the special throttling structure, and the process is as follows:

[0022] The organic sewage is pressurized by the pressurizing device, the organic sewage is heated by the heating device, and the dissolved oxygen content in the organic sewage is increased by the air nano bubble exposure device. It is worth noting that this process involves three steps of pressurization, heating, and increasing the dissolved oxygen content in the water, and the order of the three steps can be disrupted and adjusted at will. In addition, when the organic sewage contains large suspended matter and other impurities, a grid is used for initial filtration, and then pressurization, heating, and increasing the dissolved oxygen content are performed.

[0023] The pressurized, heated and oxygen-enriched organic wastewater is sent into the special throttling structure. Due to the increase in the dissolved oxygen content in the water, the efficiency of oxidation and decontamination will be greatly improved, the reaction rate will be greatly increased, and the cost will be reduced. Under the action of the pressure gradient generated in the special throttling structure, the organic matter in the water will undergo reactions including direct thermal decomposition, free radical oxidation and supercritical oxidation in the special throttling structure, thereby achieving oxidation and decontamination.

[0024] The specific process and principle of the above reaction:

[0025] The pressure gradient generated in the special throttling structure will induce cavitation. The high temperature and high pressure generated after the cavitation collapse will cause the organic pollutants to undergo cracking reactions, that is, direct thermal decomposition. At the same time, when the cavitation disappears, local high-concentration free hydroxyl radicals will be generated. High temperature and high pressure will also turn water into a supercritical state. Both supercritical water and hydroxyl radicals have strong oxidizing properties and fully contact with organic pollutants, thereby degrading organic pollutants into decomposition products mainly composed of carbon dioxide and water.

[0026] Furthermore, the decomposed organic wastewater can be passed through a wastewater content detection device and then enter a waste heat recovery device. The liquid material containing liquid water is heat recovered and heat exchanged with cold water in a heat exchanger. The water after heat exchange can be used as domestic water or for low-temperature heating. Obviously, this step is an additional link in the energy cascade utilization and is not necessary for the oxidation and decontamination of organic wastewater and can be omitted.

[0027] The general principle of the present invention is:

[0028] The special throttling structure can make the local pressure in the water lower than its saturated vapor pressure, and then cavitation will be generated in this low-pressure area. The cavitation will gradually grow as the pipeline pressure increases, and finally disappear under the pressure. First, at the moment of cavitation disappearance, local high-concentration, strong oxidizing hydroxyl free radicals will be generated in the water. These free radicals will react with organic matter to chemically oxidize, and finally degrade organic pollutants into harmless substances such as carbon dioxide and water. Secondly, the high temperature and high pressure generated by cavitation disappearance (instant high temperature 1000~5000k, high pressure 1.0×10 7 ~5.0×10 7 Pa) will not only directly crack a part of the organic pollutants, causing them to undergo direct thermal decomposition reactions, but will also cause supercritical water to be produced around them. Supercritical water also has strong oxidizing properties and can oxidize organic wastewater and release a large amount of heat, further promoting other oxidation reactions, thereby achieving the purpose of efficiently degrading organic wastewater.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention adopts a special throttling structure to produce supercritical water oxidation and other reactions, making full use of the strong oxidizing property of hydroxyl radicals to almost completely degrade chemical oxygen demand, ammonia nitrogen, thiocyanate, volatile phenols and aromatic hydrocarbons in organic sewage, reduce the emission of toxic and harmful gases, and achieve the purpose of sterilization and disinfection.

[0031] 2. Compared with the system that directly uses harsh reaction conditions to treat water to a supercritical state for organic wastewater treatment, the temperature and pressure required by the system of the present invention are lower, so the cost of the present invention is lower, the reaction is easier to trigger, and it has good economic benefits.

[0032] 3. Compared with the existing organic sewage treatment system, the present invention has a more compact structure, a simpler process and a higher overall system efficiency through reasonable design of pipeline connections.

[0033] 4. The diversity of the components and forms of the system of the present invention makes the entire system more adaptable (such as the use of Tesla valves, orifice plates and Venturi tubes, etc.). Devices with special throttling structures that can cause a sudden drop in the pressure of organic sewage can be used to treat organic sewage with the system of the present invention.

[0034] 5. The core special throttling structure of the system of the present invention has no mechanical parts such as valves, so no adjustment is required, the service life is longer, and the resistance loss is less.

[0035] 6. The present invention can utilize the waste heat of the system. The degradation products at the outlet of the special throttling structure have a relatively high temperature. By utilizing the waste heat and exchanging heat with the water on the hot user side, it can provide users with domestic hot water or low-temperature heating in winter. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the system structure in Example 1 of the present invention.

[0037] Figure 2 It is a schematic diagram of the system structure in Example 2 of the present invention.

[0038] Among them, 1-grid, 2-boosting pump, 3-first flow control valve, 4-preheating device, 5-air nano bubble exposure device, 6-first organic sewage COD detection device, 7-special throttling structure, 8-second organic sewage COD detection device, 9-pressure reducing valve, 10-heat exchanger, 11-second flow control valve. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0040] The present invention is a system and method for treating organic sewage using a special throttling structure. It is a technology based on the basic principle that the pressure difference brought by the special structure produces mechanical shear, energy impact area, and rapid changes in pressure and vacuum. It has the characteristics of simple equipment and good energy-saving effect. A large number of bubbles are generated by the pressure difference in the special throttling structure. After the bubbles burst with the pipeline, extremely high temperature and strong pressure waves are generated. The temperature and high pressure will directly decompose a part of the organic pollutants. At the same time, at this moment, the water molecules are decomposed to produce free radicals with strong oxidizing properties, and the water is in a supercritical state at this time. Not only can polar non-volatile solutes undergo free radical oxidation and supercritical oxidation reactions in this area, but also bacterial cells can be effectively lysed, and pathogenic microorganisms and organic matter in sewage can be effectively removed. This technology can not only kill microorganisms and parasite eggs, but also achieve stabilization and harmless treatment of sludge, and reduce the risk of secondary pollution to the environment. The following are two specific embodiments of the present invention.

[0041] Example 1

[0042] like Figure 1 The system shown in FIG. 1 is a system for treating organic wastewater using a special throttling structure, including:

[0043] (1) Primary filtration of organic wastewater:

[0044] The main component of the primary filtration device is the grid 1, which is mainly composed of a coarse grid and a fine grid. In this embodiment, the aperture size of the coarse grid is 10mm×10mm, and the aperture size of the fine grid is 1mm×1mm. The organic sewage to be treated passes through the grid 1 to remove larger suspended matter, floating matter, fibrous matter and solid particulate matter, thereby ensuring the normal operation of subsequent treatment equipment or structures and reducing the burden of subsequent treatment. When the organic sewage has been initially filtered and there is no solid sediment in it, this device and the corresponding steps can be omitted.

[0045] (2) Use special throttling structure to oxidize organic wastewater:

[0046] Before the organic wastewater initially filtered from the grille 1 enters the special throttling structure 7, it needs to be pressurized and heated by the pressure pump 2 and the preheating device 4, and the oxygen content is increased by the air nano bubble exposure device 5.

[0047] In this embodiment, the inlet of the pressure pump 2 is connected to the organic sewage after primary filtration from the grille 1, and the outlet is mixed with the liquid from the air nano bubble exposure device 5 through the first flow control valve 3 and connected to the preheating device 4 together.

[0048] The air nanobubble exposure device 5 is the core device of this embodiment. This structure is a key device for improving the efficiency of the system. Water and oxygen are connected to the inlet to dissolve the gas in the liquid, and then the bubbles in the mixture are cut into pieces by high-speed rotary cutting to form micro-nano bubbles. After the outlet passes through the second flow control 11, it is mixed with the liquid from the pressure pump 2 and connected to the preheating device 4.

[0049] The preheating device 4 receives the organic sewage mixed from the pressure pump 2 and the air nano bubble exposure device 5 at its inlet, passes through the first sewage content detection device 6, and is connected to the special throttling structure 7 at its outlet.

[0050] The special throttling structure 7 is the core device of this embodiment. Its special structure causes direct thermal decomposition, free radical oxidation and supercritical water oxidation reaction of organic sewage. After the bubbles generated in the reaction process burst, the local temperature and pressure both rise, wherein the reaction pressure is 20-50Mpa and the reaction temperature is 500-700°C. The decomposed organic sewage passes through the second organic sewage COD detection device 8, and the outlet is connected to the pressure reducing valve 9 and then connected to the heat exchanger 10.

[0051] (3) Waste heat recovery:

[0052] After the reaction treatment, this embodiment also performs waste heat recovery. Waste heat recovery is an additional step in this embodiment, but is not essential for the oxidation and decontamination of organic wastewater. When it is not needed, it can obviously be omitted.

[0053] In order to realize waste heat recovery, the present embodiment designs a heat exchanger 10 and a pressure reducing valve 9. The inlet at one end of the heat exchanger 10 is connected to the pressure reducing valve 9, and the inlet at the other end is connected to cold water. The organic sewage treatment product exchanges heat with the cold water in the heat exchanger 10. The outlet at one end of the heat exchanger 10 discharges the organic sewage treatment product after heat exchange, and the outlet at the other end supplies the water after heat exchange to heat users as domestic water or for low-temperature heating.

[0054] Example 2

[0055] like Figure 2 The system shown in FIG. 1 is a system for treating organic wastewater using a special throttling structure, including:

[0056] (1) Primary filtration of organic wastewater:

[0057] The structure of the primary filtration device is as in Example 1. The organic sewage to be treated passes through the grid 1 to remove large suspended solids, floating solids, fibrous materials and solid particulate materials therein, thereby ensuring the normal operation of subsequent treatment equipment or structures and reducing the burden of subsequent treatment.

[0058] (2) Use special throttling structure to oxidize organic wastewater:

[0059] Before the organic wastewater initially filtered from the grille 1 enters the special throttling structure 7, it needs to be pressurized and heated by the pressure pump 2 and the preheating device 4, and the oxygen content is increased by the air nano bubble exposure device 5.

[0060] In this embodiment, the inlet of the booster pump 2 is connected to the organic sewage after primary filtration from the grille 1, and the outlet passes through the first flow control valve 3, and the outlet is connected to the preheating device 4. The inlet of the preheating device 4 receives the organic sewage from the booster pump 2, and the outlet is connected to the air nano bubble exposure device 5.

[0061] The air nanobubble exposure device 5 is the core device of this embodiment. Its inlet is connected to oxygen and organic wastewater from the preheating device 4, the gas is dissolved in the liquid, and then the bubbles in the mixture are cut into pieces by high-speed rotary cutting to form micro-nano bubbles. The outlet is connected to a special throttling structure 7.

[0062] The special throttling structure 7 is the core device of this embodiment. Its special structure will cause the organic wastewater to undergo direct thermal decomposition, free radical oxidation and supercritical water oxidation reactions. After the bubbles generated during the reaction burst, the local temperature and pressure will increase. The reaction pressure is 20-50Mpa, and the reaction temperature is 500-700°C. The decomposed organic wastewater passes through the second organic wastewater COD detection device 8, and the outlet is connected to the pressure reducing valve 9 and then connected to the heat exchanger 10.

[0063] (3) Waste heat recovery:

[0064] After the reaction treatment, this embodiment also performs waste heat recovery. Waste heat recovery is an additional step in this embodiment, but is not essential for the oxidation and decontamination of organic wastewater. When it is not needed, it can obviously be omitted.

[0065] In order to realize waste heat recovery, the present embodiment designs a heat exchanger 10 and a pressure reducing valve 9. The inlet at one end of the heat exchanger 10 is connected to the pressure reducing valve 9, and the inlet at the other end is connected to cold water. The organic sewage treatment product exchanges heat with the cold water in the heat exchanger 10. The outlet at one end of the heat exchanger 10 discharges the organic sewage treatment product after heat exchange, and the outlet at the other end supplies the water after heat exchange to heat users as domestic water or for low-temperature heating.

[0066] Furthermore, the order of the four devices, namely, the pressure pump 2 , the first flow control valve 3 , the preheating device 4 and the air nano bubble exposure device 5 , can be disrupted.

[0067] Furthermore, the organic sewage COD detection device can measure the efficiency of the system, and can adjust the oxygenation amount of the air nano bubble exposure device 5 according to the measurement results, thereby ensuring the removal rate of organic pollutants.

[0068] Furthermore, in Example 1, the final organic wastewater treatment product can be returned to the air nanobubble exposure device 5 and introduced into the preheating device together with the organic wastewater as a liquid mixed with bubbles.

[0069] Furthermore, for wastewater containing different organic matter concentrations, the intensity of the oxidation reaction inside the special throttling structure can be flexibly adjusted by regulating parameters such as temperature, pressure and the amount of bubbles released by the bubble generating device, thereby achieving the goal of purifying organic wastewater of various concentrations.

[0070] Since the Tesla valve has similar pressure drop characteristics as the orifice plate, the Venturi tube, etc., in more embodiments of the present invention, the Tesla valve in Embodiment 1 or Embodiment 2 may be replaced by an orifice plate or a Venturi tube to achieve similar effects.

[0071] In summary, the present invention is based on a special throttling structure, making full use of the strong oxidizing properties of supercritical water and hydroxyl radicals, and almost completely degrading chemical oxygen demand, ammonia nitrogen, thiocyanate, volatile phenols and aromatic hydrocarbons in organic sewage, thereby reducing the emission of toxic and harmful gases. At the same time, the system waste heat can be utilized in the additional link, and the degradation products at the outlet of the special throttling structure have a higher temperature, which can be utilized and heat exchanged with the hot user side water to provide users with domestic hot water or low-temperature heating in winter. In addition, for sewage with different organic matter contents, the oxidation and decontamination intensity in the special throttling structure can be adjusted by adjusting the temperature, pressure and bubble content of the bubble generating device, so as to achieve the purpose of purifying organic sewage of different concentrations. In addition, compared with the harsh reaction conditions of the system directly using supercritical water reaction, the temperature and pressure required by this system are relatively low, so the cost is lower, the reaction is easier to trigger, it has good economic benefits, the overall operation efficiency of the system is high, and it meets the requirements of energy conservation and emission reduction.

Claims

1. A system for treating organic wastewater using a special throttling structure, characterized in that: It includes a pressurizing device, a heating device, an air nano bubble exposure device and a special throttling structure; The pressurizing device is used to pressurize the organic sewage, the heating device is used to heat the organic sewage, and the air nanobubble exposure device is used to increase the dissolved oxygen content in the organic sewage; The special throttling structure is a device with a pressure drop function. The organic sewage that has been pressurized, heated and has an increased dissolved oxygen content flows through the special throttling structure for oxidation and decontamination.

2. The system for treating organic wastewater using a special throttling structure according to claim 1 is characterized in that: The order of the pressurizing device, the temperature increasing device and the air nanobubble exposure device is arbitrary.

3. The system for treating organic wastewater using a special throttling structure according to claim 1 or 2, characterized in that: The pressurizing device pressurizes the organic sewage to 20-50Mpa, the heating device heats the organic sewage to 300-700°C, and the air nano bubble exposure device increases the dissolved oxygen content in the organic sewage to 50%-80%.

4. The system for treating organic wastewater using a special throttling structure according to claim 1 is characterized in that: The special throttling structure is a Tesla valve, an orifice plate or a Venturi tube.

5. The system for treating organic wastewater using a special throttling structure according to claim 1 is characterized in that: The system further comprises: a primary filtering device; The primary filtering device is used to filter the organic sewage before the pressurizing device, the heating device and the air nano bubble exposure device.

6. The system for treating organic wastewater using a special throttling structure according to claim 1 or 5, characterized in that: The system further comprises: a waste heat recovery device; The waste heat recovery device is arranged at the outlet position of the special throttling structure, and the liquid material containing liquid water is heat recovered.

7. The system for treating organic wastewater using a special throttling structure according to claim 1, characterized in that: The pressurizing device is a pressurizing pump.

8. The system for treating organic wastewater using a special throttling structure according to claim 1, characterized in that: An organic wastewater content detection device is respectively provided at the inlet and the outlet of the special throttling structure to detect the pollution removal efficiency of the throttling structure, and the oxygenation amount of the air nanobubble exposure device is controlled according to the detection result. If the organic wastewater content at the outlet is higher than the set value, the oxygenation amount is increased to adjust the reaction efficiency.

9. The system for treating organic wastewater using a special throttling structure according to claim 1, characterized in that: The outlet of the special throttling structure is connected back to the air nano bubble exposure device, and the processing product is used as a liquid mixed with bubbles.

10. A method for treating organic wastewater using a system with a special throttling structure according to any one of claims 1 to 9, characterized in that: The process is as follows: The pressurizing device is used to pressurize the organic sewage, the heating device is used to heat the organic sewage, and the air nano bubble exposure device is used to increase the dissolved oxygen content in the organic sewage; The pressurized, heated, and oxygen-enriched organic wastewater is sent to the special throttling structure. Under the action of the pressure gradient generated in the special throttling structure, reactions including direct thermal decomposition, free radical oxidation, and supercritical oxidation occur to achieve oxidative decontamination.

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