Wet oxidation treatment system and method for sludge

Abstract

The embodiment of the invention discloses a sludge wet oxidation treatment system and method.The system comprises a sludge feeding tank, a normal-pressure sludge feeding pump set used for pumping to-be-treated sludge into the sludge feeding tank, a first pressurization system used for filling gas into the sludge feeding tank, a second pressurization system used for filling gas into the sludge feeding tank, and a third pressurization system used for filling gas into the sludge feeding tank, the first pressure relief system is used for discharging redundant gas in the sludge feeding tank, the wet oxidation reactor / kettle is communicated with the sludge feeding tank, and sludge is subjected to wet catalytic oxidation reaction in the wet oxidation reactor / kettle to generate carbonized oxidation liquid. Flexible, safe and stable operation of a wet catalytic oxidation treatment process can be realized, an expensive high-pressure pump does not need to be adopted for feeding, abrasion of sludge to the high-pressure feeding pump is reduced, the problem that the sludge is prone to wall hanging and blocking is solved, the operation efficiency of the system is improved, and the maintenance cost of the system is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of sludge treatment, and in particular to a sludge wet oxidation treatment system and method. Background Art

[0002] Wet catalytic oxidation technology is an efficient, economical, safe and environmentally friendly treatment method specifically targeting difficult-to-treat environmental issues such as high-concentration organic waste liquid, sludge, kitchen waste (wet garbage), etc. This technology integrates multiple cross-disciplinary disciplines such as environmental engineering, special materials, pressure vessel design, automatic control and catalytic reaction, and is a field with high technical barriers.

[0003] In the field of sludge treatment, wet catalytic oxidation technology transports sludge with high moisture content (about 90%) to the reactor, and promotes a strong catalytic oxidation reaction in the liquid phase at a reaction temperature of 180-350°C and a reaction pressure of 3-20 MPa. This process not only completely kills pathogens and breaks the walls of sludge biological cells, but also partially oxidizes organic matter into carbon dioxide and discharges it from the tail gas, and partially converts it into soluble compounds that dissolve in the oxidizing liquid and generates biochar residue.

[0004] At present, the traditional sludge wet catalytic oxidation treatment process usually relies on high-cost high-pressure pumps to transport sludge because it needs to maintain high pressure throughout the process. That is, the traditional wet catalytic oxidation treatment process generally uses high-pressure pumps as a pumping power source to pump the material to be treated into the system. High-pressure pumps play an important role in maintaining the pressure stability in the reaction system. Their selection needs to comprehensively consider the system's pressure requirements, flow requirements, and the corrosion resistance and wear resistance of the pump, and the technical requirements are relatively high. For dissolved high-concentration organic wastewater, high-pressure pumps can ensure long-term stable and continuous transportation of materials.

[0005] However, since sludge not only contains a large amount of organic matter, such as incompletely degraded organic compounds, microbial cell remains, etc., it also contains rich inorganic components. These inorganic substances may come from minerals, heavy metal ions, sand, soil in the raw water of wastewater treatment, and chemical agents added during the treatment process. The presence of the above-mentioned inorganic substances has an important influence on the properties of sludge and the difficulty of wet catalytic oxidation treatment process. In the prior art, a common problem is that in the process of conveying sludge, due to the presence of more impurities such as inorganic substances, the stator and rotor of the high-pressure pump are susceptible to friction and wear, which increases the number of overhauls and maintenance costs, and reduces the service life of the high-pressure pump, increasing the equipment investment cost. Summary of the invention

[0006] The purpose of the present invention is to provide a sludge wet oxidation treatment system and method to solve the technical problems described in the background technology.

[0007] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: A sludge wet oxidation treatment system, comprising: A sludge feed tank, wherein a sealed storage chamber is provided in the sludge feed tank; A normal pressure mud feeding pump group, which is connected to the storage chamber inside the sludge feeding tank through a mud feeding pipe, and is used to pump the sludge to be treated into the sludge feeding tank, and a mud feeding valve group is provided on the mud feeding pipe; a first pressurizing system, the first pressurizing system being in communication with the storage chamber inside the sludge feed tank and being used for filling gas into the sludge feed tank to increase the pressure of the storage chamber inside the sludge feed tank; a first pressure relief system, the first pressure relief system being in communication with the storage chamber inside the sludge feed tank and being used for discharging excess gas inside the sludge feed tank to reduce the pressure of the storage chamber inside the sludge feed tank; A wet oxidation reactor / kettle, wherein the sludge feed tank is connected to the wet oxidation reactor / kettle through a sludge discharge pipe, the sludge feed tank delivers the sludge in its storage chamber into the wet oxidation reactor / kettle for wet catalytic oxidation reaction, and a sludge discharge valve group is provided on the sludge discharge pipe; A heating system is used to heat the sludge inside the wet oxidation reactor / kettle to increase the reaction temperature of the sludge inside the wet oxidation reactor / kettle, so that the sludge inside the wet oxidation reactor / kettle undergoes a wet catalytic oxidation reaction and generates a carbonized oxidation liquid.

[0008] In one embodiment, it further includes: A sludge pretreatment system is used to remove impurities in the sludge and add reaction aids to the sludge to increase the fluidity of the sludge. The sludge pretreatment system is arranged on the front side of the atmospheric pressure mud inlet pump group, and the suction end of the atmospheric pressure mud inlet pump group is connected to the sludge pretreatment system through a mud delivery pipe.

[0009] In one embodiment, it further includes: A separation tank, which is connected to the wet oxidation reactor / kettle via a discharge pipe, and a discharge valve group is provided on the discharge pipe. The separation tank is used to relieve the pressure and cool the carbonized oxidation liquid in the tank body, and to separate the gas and liquid; A plate and frame filter press, wherein the plate and frame filter press is connected to the separation tank through a material guide pipe, and a material guide pump is provided on the material guide pipe. The plate and frame filter press is used to mechanically dehydrate the carbonized oxidation liquid after gas-liquid separation to generate a semi-dried carbon cake, and the lower filtrate generated by the plate and frame filter press during mechanical dehydration is refluxed to the front end of the sewage treatment plant through a pipeline for treatment.

[0010] In one embodiment, it further includes: a second pressurizing system, the second pressurizing system being in communication with the reaction chamber inside the wet oxidation reactor / kettle and used for charging gas into the wet oxidation reactor / kettle to increase the reaction pressure of the reaction chamber inside the wet oxidation reactor / kettle; A second pressure relief system is connected to the reaction chamber inside the wet oxidation reactor / kettle and is used to discharge excess gas inside the wet oxidation reactor / kettle to reduce the reaction pressure of the reaction chamber inside the wet oxidation reactor / kettle.

[0011] In one embodiment, it further includes: - exhaust gas treatment system; The first pressure relief system comprises a first pressure relief exhaust pipe connected to the sludge feed tank and the tail gas treatment system, and a first pressure relief valve group arranged on the first pressure relief exhaust pipe; The second pressure relief system comprises a second pressure relief exhaust pipe connected to the wet oxidation reactor / kettle and the tail gas treatment system, and a second pressure relief valve group arranged on the second pressure relief exhaust pipe; The gas outlet of the separation tank is connected to the tail gas treatment system through the tail gas pipe; The tail gas treatment system performs harmless treatment on the gas introduced therein, and discharges the treated tail gas that meets the standards.

[0012] In one embodiment, the heating system comprises: A heat transfer oil furnace, the oil outlet of the heat transfer oil furnace is connected to the internal heating chamber of the hot bath jacket of the wet oxidation reactor / kettle through a hot oil pipe, the internal heating chamber of the hot bath jacket is also connected to the oil return port of the heat transfer oil furnace through an oil return pipe, and an oil return pump is provided on the oil return pipe, and the oil return pump enables the heat transfer oil as a heat carrier to circulate between the heat transfer oil furnace and the internal heating chamber of the hot bath jacket.

[0013] In one embodiment, the sludge feed tank is disposed directly above the wet oxidation reactor / kettle.

[0014] In one embodiment, the gas injected into the sludge feeding tank by the first pressurizing system is air or oxygen.

[0015] In one embodiment, the gas injected into the wet oxidation reactor / kettle by the second pressurizing system is air or oxygen.

[0016] In one embodiment, the present invention further provides a sludge wet oxidation treatment method, which is used in the treatment process of the above-mentioned sludge wet oxidation treatment system, comprising the following steps: Step S1, the control system opens the mud inlet valve group, pumps the sludge that meets the treatment requirements into the sludge feed tank at normal pressure through the normal pressure mud inlet pump group, and closes the mud inlet valve group through the control system after the pumping is completed; Step S2, the control system fills gas into the storage chamber inside the sludge feed tank through the first pressurizing system, so that the sludge feed tank reaches a high pressure state of a set pressure; Step S3, the control system opens the mud discharge valve group to allow all the sludge in the sludge feed tank to enter the reaction chamber of the wet oxidation reactor / kettle, and closes the mud discharge valve group through the control system after all the sludge enters the wet oxidation reactor / kettle; Step S4, said step S4 comprises two parts, step S4A and step S4B, which are performed simultaneously, wherein: Step S4A, the control system adjusts the temperature and pressure inside the wet oxidation reactor / kettle to set values, so that the sludge undergoes sufficient wet catalytic oxidation reaction in the wet oxidation reactor / kettle and forms a carbonized oxidation liquid; Step S4B, the control system discharges part of the gas inside the sludge feed tank through the first pressure relief system to restore the internal pressure of the sludge feed tank to a normal pressure state, and repeats the operations of steps S1 to S2 to pump the next batch of sludge into the sludge feed tank and adjust the sludge feed tank to a high pressure state; Step S5, the control system sends the carbonized oxidation liquid generated after sufficient catalytic oxidation reaction in the wet oxidation reactor / kettle into a separation tank for pressure relief and cooling; Step S6, the cooled carbonized oxidized liquid is fed into a plate-and-frame filter press in batches through a feed pump for mechanical dehydration to generate a semi-dried carbon cake, and the lower filtrate generated during dehydration is returned to the front end of the sewage treatment plant through a pipeline for treatment; Step S7, repeating the operations from step S3 to step S6 to perform wet catalytic oxidation treatment on subsequent batches of sludge.

[0017] Compared with the prior art, the beneficial effects of a sludge wet oxidation treatment system and method provided by an embodiment of the present invention are: the process of the present invention is simple, and a sludge feed tank with a seamless switching function between normal pressure and high pressure is cleverly integrated into the front end of the wet catalytic oxidation treatment process, which not only ensures the smooth and efficient supply of sludge raw materials to the pressurized reactor / kettle, but also greatly improves the safety and flexibility of the entire treatment process. More importantly, the system and method involved in the present invention completely get rid of the traditional process's dependence on high-pressure pumps in the sludge feeding link, and instead adopts a more economical and practical normal pressure pump as the feed power source, which not only greatly reduces the initial equipment investment cost, but also effectively alleviates the problem of frequent maintenance of the feed pump due to wear by reducing the direct pumping of sludge under high-pressure environment, greatly reducing the maintenance frequency and maintenance cost, thereby significantly improving the operating efficiency and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or other aspects and advantages of the embodiments of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings, which are only exemplary and do not limit the present invention, wherein: Figure 1 It is a schematic structural diagram of a sludge wet oxidation treatment system involved in an embodiment of the present invention.

[0019] Figure numerals: 1, sludge pretreatment system; 2, sludge delivery pipe; 3, normal pressure sludge inlet pump group; 4, sludge inlet pipe; 5, sludge inlet valve group; 6, sludge feed tank; 7, sludge outlet pipe; 8, sludge outlet valve group; 9, wet oxidation reactor / kettle; 10, discharge pipe; 11, discharge valve group; 12, separation tank; 13, feed guide pump; 14, feed guide pipe; 15, plate and frame filter press; 16, first pressurizing system; 1601, first air compressor; 1602, first pressurizing pipe; 1603, first pressurizing valve group; 17, second Pressurization system; 1701, second air compressor; 1702, second pressurization pipe; 1703, second pressurization valve group; 18, first pressure relief system; 1801, first pressure relief exhaust pipe; 1802, first pressure relief valve group; 19, second pressure relief system; 1901, second pressure relief exhaust pipe; 1902, second pressure relief valve group; 20, exhaust gas treatment system; 21, heating system; 2101, thermal oil furnace; 2102, hot oil pipe; 2103, return oil pipe; 2104, return oil pump; 22, exhaust pipe. DETAILED DESCRIPTION

[0020] Hereinafter, an embodiment of a sludge wet oxidation treatment system and method of the present invention will be described with reference to the accompanying drawings. The embodiments described herein are specific embodiments of the present invention, which are used to illustrate the concept of the present invention. They are all explanatory and exemplary and should not be interpreted as limiting the embodiments of the present invention and the scope of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims and the specification of this application, including technical solutions that adopt any obvious replacements and modifications to the embodiments described herein.

[0021] In the description of the present invention, it should be noted that the terms "front", "rear", "left", "right", "top", "bottom", "up", "down", "inside", "outside", "horizontal", "vertical", "upright", "oblique", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc., are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0022] The drawings of this specification are schematic diagrams, which assist in explaining the concept of the present invention and schematically show the shapes of various parts and their mutual relationships. Please note that in order to clearly show the structures of various components of the embodiments of the present invention, the drawings are not drawn according to the same scale. The same reference numerals are used to represent the same parts.

[0023] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. Figure 1 , the preferred embodiments of the present invention are further described in detail: like Figure 1 As shown, a preferred embodiment of the present invention provides a sludge wet oxidation treatment system, comprising: A sludge feed tank 6, wherein a sealed storage chamber is provided inside the sludge feed tank 6. The sludge feed tank 6 is designed to be a device capable of switching between normal pressure and high pressure. Therefore, the sludge feed tank 6 needs to be made of pressure-resistant and anti-corrosion materials, and its pressure resistance level should be greater than or equal to the maximum pressure during the operation of the wet oxidation reactor / kettle 9. This design provides great flexibility and adaptability, so that it can cooperate with the normal pressure mud feed pump group 3 to realize sludge feeding, and further cooperate with the first pressurizing system 16 to provide the subsequent high-pressure wet oxidation reactor / kettle 9 with sludge materials to be treated. The sludge feed tank 6 is divided into The sludge zone at the bottom and the gas zone at the top, wherein the volume of the sludge zone matches the volume of sludge that can be held and processed by the wet oxidation reactor / kettle 9 at a time, and in order to reduce the difficulty of the sludge entering the wet oxidation reactor / kettle 9 and facilitate the sludge material to flow from the sludge feed tank 6 into the wet oxidation reactor / kettle 9, in a preferred embodiment, in the vertical direction, the sludge feed tank 6 is arranged directly above the wet oxidation reactor / kettle 9, so that the sludge in the sludge feed tank 6 can smoothly enter the wet oxidation reactor / kettle 9 under the combined effect of the pressure in the tank and the gravity of the sludge to realize material transportation; A normal pressure mud feeding pump group 3, the normal pressure mud feeding pump group 3 is connected with the storage chamber inside the sludge feeding tank 6 through the mud feeding pipe 4, and is used to pump the sludge to be treated into the sludge feeding tank 6, and the mud feeding pipe 4 is provided with a mud feeding valve group 5. In order to ensure the smooth operation of the whole system, the water content of the sludge pumped by the normal pressure mud feeding pump group 3 should be ≥90%, wherein the normal pressure mud feeding pump group 3 can select a normal pressure mud feeding pump (such as a screw pump with a suitable head, etc.) with suitable pump speed and flow according to the process parameters, and reasonably configure the number and head of the pumps according to the process requirements to ensure that the sludge can be continuously fed into the sludge feeding tank 6. Since the design and manufacture of the normal pressure mud feeding pump are usually simpler than those of the high pressure pump, it does not need to withstand extremely high pressure and does not need to be made of special pressure-bearing materials. Therefore, the equipment procurement cost is relatively low. Moreover, due to the low working pressure, the wear and failure rate of the normal pressure mud feeding pump is relatively low. Based on this, the maintenance times, maintenance frequency and maintenance costs can also be reduced; A first pressurizing system 16, the first pressurizing system 16 is connected to the storage chamber inside the sludge feed tank 6, and is used to fill gas into the sludge feed tank 6 to increase the pressure of the storage chamber inside the sludge feed tank 6. At this time, the gas filled into the sludge feed tank 6 by the first pressurizing system 16 is air or oxygen, and its purpose is to increase the pressure so as to press the sludge into the wet oxidation reactor / kettle 9. Of course, it should be noted that the pressure of the air compressor needs to be controlled to be less than the maximum bearing pressure of the sludge feed tank 6. In a preferred embodiment, the first pressurizing system 16 includes at least one first air compressor 1601, and the first air compressor 1601 is connected to the sludge feed tank 6 through a first pressurizing pipe 1602. The gas area at the top of the material tank 6 is connected to each other so that compressed gas can be pumped into the sludge feed tank 6 to realize the switching of the sludge feed tank 6 from a normal pressure state to a high pressure state. The valve group provided by the air compressor can play an airtight role to prevent the gas filled in the sludge feed tank 6 from leaking. Preferably, in a preferred embodiment, a first pressurizing valve group 1603 is also provided on the first pressurizing pipe 1602. The form of the first pressurizing valve group 1603 can be reasonably selected according to demand. In terms of safety, the first pressurizing valve group 1603 can play a role in preventing overpressure. During the operation of the air compressor, the output pressure may increase abnormally due to a fault (such as failure of the pressure control system). If there is no pressure between the air compressor and the sludge feed tank 6 to be pressurized, Valve, excessive pressure will be directly transmitted to the tank, causing serious safety accidents such as tank rupture, etc., valves (such as safety valves, pressure regulating valves, etc.) are set. When the pressure exceeds the set value, the safety valve automatically releases the pressure, and the pressure regulating valve adjusts the gas flow to maintain the pressure in the tank within a safe range. At the same time, it can also play a role in isolation and protection. For example, when the air compressor is overhauled, maintained or fails, closing the valve can isolate the air compressor from the pressurized sludge feed tank 6 to prevent the high-pressure gas in the tank from flowing back to the air compressor and causing harm to the maintenance personnel, thereby ensuring the safety of overhaul; at the same time, in terms of operation control, it can also play a start-stop control role. Specifically, when the air compressor is started and stopped, the air flow impact will cause damage to the tank. The valve can control the gas to slowly enter the tank, reduce the start-up impact, protect the tank body and connecting parts, and when the air compressor is stopped, closing the valve can prevent the gas in the tank from flowing back, which is conducive to the next start. At the same time, the valve can also play a role in regulating flow and pressure. During the production process, the pressure in the tank and the gas flow demand will change. Additional valves (such as throttle valves and regulating valves) can adjust the gas flow entering the tank as needed, accurately control the pressure in the tank, and meet different production process requirements; in addition, in terms of system maintenance, the valve can also facilitate maintenance. If one of the air compressor or the tank body needs to be repaired, closing the middle valve can isolate the two, so that the maintenance work does not interfere with each other, narrowing the maintenance scope and improving maintenance efficiency; A first pressure relief system 18, which is connected to the storage chamber inside the sludge feed tank 6 and is used to discharge excess gas inside the sludge feed tank 6 to reduce the pressure of the storage chamber inside the sludge feed tank 6. The first pressure relief system 18 includes a first pressure relief exhaust pipe 1801 connected to the sludge feed tank 6 and the tail gas treatment system 20, and a first pressure relief valve group 1802 arranged on the first pressure relief exhaust pipe 1801; A wet oxidation reactor / kettle 9, wherein the sludge feed tank 6 is connected to the wet oxidation reactor / kettle 9 through a sludge outlet pipe 7, and the sludge feed tank 6 delivers the sludge in its storage chamber into the wet oxidation reactor / kettle 9 for wet catalytic oxidation reaction, and the sludge outlet pipe 7 is provided with a sludge outlet valve group 8. In a preferred embodiment, a mechanical stirring or magnetic stirring device is provided in the wet oxidation reactor / kettle 9 to stir the sludge to be treated to promote the occurrence of the catalytic oxidation reaction, and preferably a sealed mechanical stirring method is used. The reactor / kettle is used to break the cell wall of organic matter in the high-temperature mud, and part of the organic matter is oxidized into carbon dioxide and discharged from the tail gas through the second pressure relief system 19, and part of it is converted into soluble compounds and dissolved in the high-temperature carbonization oxidation liquid (mostly small molecular organic acids), that is, the sludge enters the wet oxidation reactor / kettle 9, at a pressure of 2.5 to 5.0 MPa and a pressure of 180 to 250 In an environment with a temperature of ℃, the organic cells in the high-temperature mud are broken, and the bound water is converted into free water and released. While releasing heat, a high-temperature carbonized oxidation liquid of carbon-like substances is formed, thereby changing the physical and chemical shape of the mud and greatly improving the dehydration performance. It should be noted that the sludge needs to stay in the wet oxidation reactor / kettle 9 for a sufficient time to allow the sludge to fully complete the wall breaking, decomposition, carbonization, and polymerization processes, and finally form a carbonized oxidation liquid; A heating system 21, the heating system 21 is used to heat the sludge inside the wet oxidation reactor / kettle 9 to increase the reaction temperature (180-250°C) of the sludge inside the wet oxidation reactor / kettle 9, so that the sludge inside the wet oxidation reactor / kettle 9 undergoes a wet catalytic oxidation reaction and generates a carbonized oxidation liquid. The heating system 21 can use an economical heating method such as electric heating or hot oil heating. In a preferred embodiment, hot oil heating is used, that is, the wet oxidation reactor / kettle 9 is an oil bath heating reactor / kettle, which heats the reactants by passing hot oil into the jacket of the reactor / kettle, that is, the heating system 21 includes: a thermal oil furnace 2101, the thermal oil furnace 2102 The hot oil furnace 2101 is a special industrial furnace using heat transfer oil as a heat carrier, and its oil outlet is connected to the internal heating chamber of the hot bath jacket of the wet oxidation reactor / kettle 9 through a hot oil pipe 2102. The internal heating chamber of the hot bath jacket is also connected to the oil return port of the hot oil furnace 2101 through an oil return pipe 2103, and an oil return pump 2104 is provided on the oil return pipe 2103. The oil return pump 2104 allows the heat transfer oil as a heat carrier to circulate between the hot oil furnace 2101 and the internal heating chamber of the hot bath jacket, so as to transfer heat to the sludge through the inner wall of the jacket; A separation tank 12, the separation tank 12 is connected to the wet oxidation reactor / kettle 9 through a discharge pipe 10, and the discharge pipe 10 is provided with a discharge valve group 11, the separation tank 12 is used to release the pressure and cool the carbonized oxidation liquid in the tank body, and to separate the gas and liquid; A plate-frame filter press 15, wherein the plate-frame filter press 15 is connected to the separation tank 12 via a feed guide pipe 14, and a feed guide pump 13 is provided on the feed guide pipe 14. The plate-frame filter press 15 is used to mechanically dehydrate the carbonized oxidized liquid after gas-liquid separation to generate a semi-dried carbon cake, and the lower filtrate generated by the plate-frame filter press 15 during mechanical dehydration is refluxed to the front end of the sewage treatment plant through a pipeline for treatment; Under the condition of ensuring the operating pressure of the system in a specially designed pressure relief system, the separation tank 12 (single or multi-stage) is used to cool the carbonized oxidation liquid to a temperature of ≤60°C to meet the requirements of the filter cloth of the plate and frame filter press 15; gas-liquid separation is performed at the same time, and then the carbonized oxidation liquid after gas-liquid separation and cooling is injected into the plate and frame filter press 15 in batches through the feed pump 13 (for example, a screw pump can be used) for solid-liquid separation, and mechanical dehydration is performed to obtain a semi-dried carbon cake with a moisture content of about 30%. The lower filtrate after the filter press treatment is returned to the front end of the sewage treatment plant through a pipeline for treatment. At the same time, the separated tail gas enters the tail gas treatment system 20 through the tail gas pipe 22 for harmless treatment and then discharged. Of course, the waste heat of the separation tank 12 can also be used for secondary utilization within or outside the system, for example, the sludge in the sludge feed tank 6 is preheated by the system waste heat. Since there are often various impurities (such as hair, large particles, etc.) in the sludge, the accumulation of such impurities often leads to a reduction in the effective aperture in the pipeline, and even causes the risk of pipe blockage. In order to better and more smoothly carry out subsequent pyrolysis treatment of the sludge, in a preferred embodiment, a sludge wet oxidation treatment system described in the preferred embodiment of the present invention also includes: A sludge pretreatment system 1, which is used to remove impurities (such as hair, large particles, etc.) in the sludge so that the subsequent pyrolysis treatment of the sludge can proceed smoothly. At the same time, the sludge pretreatment system 1 can also add catalysts (acids or alkalis), scale inhibitors and other reaction aids to the sludge in proportion through a dosing pump to increase the fluidity of the sludge and prevent the sludge from forming precipitation and scaling problems during the heat exchange process. The sludge pretreatment system 1 is arranged on the front side of the atmospheric pressure mud inlet pump group 3, and the suction end of the atmospheric pressure mud inlet pump group 3 is connected to the sludge pretreatment system 1 through a mud delivery pipe 2; Considering that the sludge needs to control the appropriate temperature and pressure when undergoing the catalytic oxidation reaction in the wet oxidation reactor / kettle 9, in order to enable the entire system to more flexibly and conveniently adjust the internal pressure of the wet oxidation reactor / kettle 9, a sludge wet oxidation treatment system described in a preferred embodiment of the present invention further includes: A second pressurizing system 17, the second pressurizing system 17 is connected to the reaction chamber inside the wet oxidation reactor / kettle 9, and is used to fill the wet oxidation reactor / kettle 9 with gas to increase the reaction pressure of the reaction chamber inside the wet oxidation reactor / kettle 9. Here, the gas filled into the wet oxidation reactor / kettle 9 by the second pressurizing system 17 is air or oxygen, and its purpose is not only to increase the oxygen concentration to achieve aerobic carbonization, but also to increase the reaction pressure when the pressure inside the wet oxidation reactor / kettle 9 is insufficient, so as to control the pressure in the reactor / kettle at 2.5 to 5.0 Mpa, in a preferred embodiment, the second pressurizing system 17 includes at least one second air compressor 1701, and the second air compressor 1701 is connected to the internal reaction chamber of the wet oxidation reactor / kettle 9 through a second pressurizing pipe 1702 to pump gas into the wet oxidation reactor / kettle 9 to increase the reaction pressure inside the wet oxidation reactor / kettle 9. The valve group provided by the air compressor can play an airtight role to avoid leakage of the gas filled in the wet oxidation reactor / kettle 9. Preferably, in a preferred embodiment, the second pressurizing pipe 1702 is also provided with a second pressurizing valve group 1703, and the second pressurizing valve group The form of 1703 can be reasonably selected according to the needs. In terms of safety, the second pressure valve group 1703 can play a role in preventing overpressure. During the operation of the air compressor, the output pressure may increase abnormally due to a fault (such as failure of the pressure control system). If there is no valve between the air compressor and the wet oxidation reactor / kettle 9 to be pressurized, the excessive pressure will be directly transmitted to the reactor / kettle, causing serious safety accidents such as reactor / kettle rupture. Valves (such as safety valves, pressure regulating valves, etc.) are set. When the pressure exceeds the set value, the safety valve automatically releases the pressure, and the pressure regulating valve adjusts the gas flow to maintain the pressure in the reactor / kettle within a safe range. At the same time, it can also play the role of isolation and protection. For example, when the air compressor is overhauled, maintained or fails, closing the valve can isolate the air compressor from the humidified oxidation reactor / kettle 9 to prevent the high-pressure gas in the reactor / kettle from flowing back to the air compressor and causing harm to the maintenance personnel, thereby ensuring the safety of overhaul. At the same time, in terms of operation control, it can also play the role of start-stop control. Specifically, when the air compressor is started and stopped, the air flow impact will affect the reactor / kettle. The valve can be used to control the gas to slowly enter the reactor / kettle, reduce the start-up impact, protect the reactor / kettle and connecting parts, and stop the air compressor. Closing the valve can prevent gas from flowing back into the reactor / kettle, which is beneficial for the next start-up. At the same time, the valve can also play a role in regulating flow and pressure. During the production process, the pressure and gas flow demand in the reactor / kettle will change. Additional valves (such as throttle valves and regulating valves) can adjust the gas flow entering the reactor / kettle as needed, accurately control the pressure in the reactor / kettle, and meet different production process requirements; in addition, in terms of system maintenance, the valve can also facilitate maintenance. If either the air compressor or the reactor / kettle needs to be repaired, closing the intermediate valve can isolate the two, so that the maintenance work does not interfere with each other, narrowing the maintenance scope and improving maintenance efficiency;. A second pressure relief system 19, which is connected to the reaction chamber inside the wet oxidation reactor / kettle 9 and is used to discharge excess gas inside the wet oxidation reactor / kettle 9 to reduce the reaction pressure in the reaction chamber inside the wet oxidation reactor / kettle 9. The second pressure relief system 19 includes a second pressure relief exhaust pipe 1901 connected to the wet oxidation reactor / kettle 9 and the tail gas treatment system 20, and a second pressure relief valve group 1902 arranged on the second pressure relief exhaust pipe 1901; Of course, in order to avoid environmental pollution caused by direct discharge of tail gas released from some links of the system, a sludge wet oxidation treatment system described in a preferred embodiment of the present invention also includes: An exhaust gas treatment system 20; The gas outlet of the separation tank 12 is connected to the tail gas treatment system 20 through the tail gas pipe 22; The exhaust gas treatment system 20 performs harmless treatment (including but not limited to deodorization treatment, etc.) on the gas introduced therein, and discharges the exhaust gas that meets the standards after treatment.

[0024] In addition, in a preferred embodiment, the present invention also provides a sludge wet oxidation treatment method, which is used in the treatment process of the above-mentioned sludge wet oxidation treatment system, comprising the following steps: Step S0, the control system sends the sludge to be treated after impurities are removed into the sludge pretreatment system 1, prepares the sludge into a slurry with a moisture content of ≥90% and a certain fluidity, and adds a quantitative catalyst (acid or alkali), a scale inhibitor and other reaction aids to increase the fluidity of the sludge; Step S1, the control system opens the mud inlet valve group 5, starts the normal pressure mud inlet pump group 3, and continuously pumps the pre-treated sludge that meets the treatment requirements into the normal pressure sludge feed tank 6 through the normal pressure mud inlet pump group 3, and after the pumping is completed (that is, after the sludge in the tank 6 reaches a predetermined liquid level), the mud inlet valve group 5 is closed by the control system. In order to achieve the above purpose, under normal circumstances, the sludge feed tank 6 needs to be equipped with a system for observing the liquid level and a system for measuring and feeding back the pressure in the tank. Of course, when the normal pressure mud inlet pump group 3 is working, the first pressure relief system 18 can be opened synchronously to discharge part of the sludge as it is pumped in, thereby reducing the difficulty of pumping. Of course, if the normal pressure mud inlet pump group 3 can work normally, the first pressure relief system 18 can also remain closed to reduce the workload of subsequent pressure switching to a high pressure state; Step S2, the control system fills gas into the storage chamber inside the sludge feed tank 6 through the first pressurizing system 16, so that the sludge feed tank 6 reaches a high pressure state of a set pressure. When the pressure inside the sludge feed tank 6 exceeds the set pressure, the first pressure relief system 18 connected to the tail gas treatment system 20 can automatically start to relieve pressure and release gas to release excess gas to avoid damage to the tank body; Step S3, the control system opens the mud discharge valve group 8, so that all the sludge in the sludge feed tank 6 enters the reaction chamber of the wet oxidation reactor / kettle 9 from the bottom mud outlet of the sludge feed tank 6 through the mud discharge pipe 7 under the combined effect of the pressure in the top gas zone and the dead weight, and closes the mud discharge valve group 8 through the control system after all the sludge enters the wet oxidation reactor / kettle 9; Step S4, said step S4 comprises two parts, step S4A and step S4B, which are performed simultaneously, wherein: Step S4A, the control system adjusts the temperature and pressure inside the wet oxidation reactor / kettle 9 to the set value (that is, the control system adjusts the temperature and pressure inside the wet oxidation reactor / kettle 9 by controlling the second pressurizing system 17, the second pressure relief system 19 and the heating system 21. Taking temperature adjustment as an example, at this time, the control system turns on the thermal oil furnace 2101 heating device to increase the temperature of the reactor / kettle sludge, and starts the stirring system inside the reactor / kettle to promote the sludge in the reactor / kettle to undergo catalytic oxidation reaction), so that the sludge undergoes sufficient wet catalytic oxidation reaction in the wet oxidation reactor / kettle 9 and forms a carbonized oxidation liquid. During the reaction process, the pressure and temperature in the reactor / kettle are maintained at a pressure of 2.5 to 5.0 MPa and a temperature of 180 to 250° C., respectively. When the pressure is insufficient, the pressure is supplemented by the second air compressor 1701 connected to the reactor / kettle. When the pressure is too high, the pressure is relieved by the second pressure relief system 19. The sludge stays in the reactor / kettle for a sufficient time to complete the wall breaking, decomposition, carbonization, and polymerization of the sludge, and finally forms a carbonized oxidation liquid; Step S4B, the control system discharges part of the gas inside the sludge feed tank 6 through the first pressure relief system 18 to restore the internal pressure of the sludge feed tank 6 to a normal pressure state, and repeats the operations of steps S1 to S2 to pump the next batch of sludge into the sludge feed tank 6 and adjust the sludge feed tank 6 to a high pressure state so that the next batch of sludge can be injected into the wet oxidation reactor / kettle 9 while being emptied, thereby avoiding idleness of the equipment; Step S5, the control system sends the carbonized oxidation liquid generated after the sufficient catalytic oxidation reaction in the wet oxidation reactor / kettle 9 to the separation tank 12 for pressure relief and cooling. Specifically, after the reaction is completed, the control system opens the discharge valve group 11, discharges the carbonized oxidation liquid into the separation tank 12 for pressure relief and cooling, and closes the discharge valve group 11 after the discharge is completed; Step S6, the carbonized oxidized liquid after gas-liquid separation and cooling (≤60°C) is injected into the plate-frame filter press 15 in batches through the feed pump 13 and the feed pipe 14, and the plate-frame filter press 15 mechanically dehydrates the carbonized oxidized liquid to obtain a semi-dried carbon cake with a moisture content of about 30%, and the control system returns the lower filtrate generated by the plate-frame filter press 15 during mechanical dehydration to the front end of the sewage treatment plant through a pipeline for treatment; Step S7, repeating the operations from step S3 to step S6 to perform wet catalytic oxidation treatment on subsequent batches of sludge.

[0025] In the embodiment of the present invention, a sludge feed tank 6 with a seamless switching function between normal pressure and high pressure is vertically arranged on the top of the wet catalytic oxidation treatment process reactor / kettle, so that the wet catalytic oxidation treatment process can be operated flexibly, safely and stably. Not only does it not need to use an expensive high-pressure pump for feeding, reducing the wear of the high-pressure feed pump by the sludge, but it also solves the problem of sludge easily sticking to the wall and clogging, thereby improving the operating efficiency of the system and reducing the maintenance cost of the system.

[0026] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A sludge wet oxidation treatment system, characterized in that: include: A sludge feeding tank (6), wherein a sealed material storage chamber is provided in the sludge feeding tank (6); a normal-pressure mud-feeding pump group (3), the normal-pressure mud-feeding pump group (3) being connected to a storage chamber inside a sludge feed tank (6) via a mud-feeding pipe (4), and being used for pumping the sludge to be treated into the sludge feed tank (6), and the mud-feeding pipe (4) being provided with a mud-feeding valve group (5); a first pressurizing system (16), the first pressurizing system (16) being in communication with the storage chamber inside the sludge feed tank (6) and being used for filling gas into the sludge feed tank (6) to increase the pressure of the storage chamber inside the sludge feed tank (6); a first pressure relief system (18), the first pressure relief system (18) being in communication with the storage chamber inside the sludge feed tank (6) and being used for discharging excess gas inside the sludge feed tank (6) so as to reduce the pressure in the storage chamber inside the sludge feed tank (6); A wet oxidation reactor / kettle (9), wherein the sludge feed tank (6) is connected to the wet oxidation reactor / kettle (9) via a sludge discharge pipe (7), the sludge feed tank (6) delivers the sludge in its storage chamber into the wet oxidation reactor / kettle (9) for wet catalytic oxidation reaction, and the sludge discharge pipe (7) is provided with a sludge discharge valve group (8); A heating system (21) is used to heat the sludge inside the wet oxidation reactor / kettle (9) to increase the reaction temperature of the sludge inside the wet oxidation reactor / kettle (9), so that the sludge inside the wet oxidation reactor / kettle (9) undergoes a wet catalytic oxidation reaction and generates a carbonized oxidation liquid.

2. A sludge wet oxidation treatment system according to claim 1, characterized in that: Also includes: A sludge pretreatment system (1) is used to remove impurities from the sludge and add a reaction aid to the sludge to increase the fluidity of the sludge. The sludge pretreatment system (1) is arranged on the front side of a normal pressure sludge feeding pump group (3). The suction end of the normal pressure sludge feeding pump group (3) is connected to the sludge pretreatment system (1) through a sludge delivery pipe (2).

3. A sludge wet oxidation treatment system according to claim 1, characterized in that: Also includes, a separation tank (12), wherein the separation tank (12) is connected to the wet oxidation reactor / kettle (9) via a discharge pipe (10), and a discharge valve group (11) is provided on the discharge pipe (10), and the separation tank (12) is used to release the pressure and cool the carbonized oxidation liquid in the tank body, and to separate the gas and liquid; A plate and frame filter press (15), wherein the plate and frame filter press (15) is connected to the separation tank (12) via a material guide pipe (14), and a material guide pump (13) is provided on the material guide pipe (14). The plate and frame filter press (15) is used to mechanically dehydrate the carbonized oxidized liquid after gas-liquid separation to generate a semi-dried carbon cake, and the lower filtrate generated by the plate and frame filter press (15) during mechanical dehydration is returned to the front end of the sewage treatment plant through a pipeline for treatment.

4. A sludge wet oxidation treatment system according to claim 3, characterized in that: Also includes: a second pressurizing system (17), the second pressurizing system (17) being in communication with the reaction chamber inside the wet oxidation reactor / kettle (9) and being used for filling gas into the wet oxidation reactor / kettle (9) to increase the reaction pressure of the reaction chamber inside the wet oxidation reactor / kettle (9); A second pressure relief system (19), the second pressure relief system (19) is connected to the reaction chamber inside the wet oxidation reactor / kettle (9), and is used to discharge excess gas inside the wet oxidation reactor / kettle (9) to reduce the reaction pressure in the reaction chamber inside the wet oxidation reactor / kettle (9).

5. A sludge wet oxidation treatment system according to claim 4, characterized in that: Also includes: an exhaust gas treatment system (20); The first pressure relief system (18) comprises a first pressure relief exhaust pipe (1801) connected to the sludge feed tank (6) and the tail gas treatment system (20), and a first pressure relief valve group (1802) arranged on the first pressure relief exhaust pipe (1801); The second pressure relief system (19) comprises a second pressure relief exhaust pipe (1901) connected to the wet oxidation reactor / kettle (9) and the tail gas treatment system (20), and a second pressure relief valve group (1902) arranged on the second pressure relief exhaust pipe (1901); The gas outlet of the separation tank (12) is connected to the tail gas treatment system (20) through the tail gas pipe (22); The exhaust gas treatment system (20) performs harmless treatment on the gas introduced into the system, and discharges the exhaust gas that meets the standards after treatment.

6. A sludge wet oxidation treatment system according to claim 1, characterized in that: The heating system (21) comprises: A heat transfer oil furnace (2101), wherein the oil outlet of the heat transfer oil furnace (2101) is connected to the internal heating chamber of the hot bath jacket of the wet oxidation reactor / kettle (9) via a hot oil pipe (2102), and the internal heating chamber of the hot bath jacket is also connected to the oil return port of the heat transfer oil furnace (2101) via an oil return pipe (2103), and an oil return pump (2104) is provided on the oil return pipe (2103). The oil return pump (2104) enables the heat transfer oil as a heat carrier to circulate between the heat transfer oil furnace (2101) and the internal heating chamber of the hot bath jacket.

7. A sludge wet oxidation treatment system according to claim 1, characterized in that: The sludge feed tank (6) is arranged directly above the wet oxidation reactor / kettle (9).

8. A sludge wet oxidation treatment system according to claim 1, characterized in that: The gas injected into the sludge feeding tank (6) by the first pressurizing system (16) is air or oxygen.

9. A sludge wet oxidation treatment system according to claim 4, characterized in that: The gas injected into the wet oxidation reactor / kettle (9) by the second pressurizing system (17) is air or oxygen.

10. A sludge wet oxidation treatment method, used in the treatment process of a sludge wet oxidation treatment system as claimed in any one of claims 1 to 9, characterized in that: The steps include: Step S1, the control system opens the mud inlet valve group (5), pumps the sludge that meets the treatment requirements into the sludge feed tank (6) at normal pressure through the normal pressure mud inlet pump group (3), and closes the mud inlet valve group (5) through the control system after the pumping is completed; Step S2, the control system fills gas into the storage chamber inside the sludge feed tank (6) through the first pressurizing system (16), so that the sludge feed tank (6) reaches a high pressure state of a set pressure; Step S3, the control system opens the mud discharge valve group (8) to allow all the sludge in the sludge feed tank (6) to enter the reaction chamber of the wet oxidation reactor / kettle (9), and after all the sludge enters the wet oxidation reactor / kettle (9), the control system closes the mud discharge valve group (8); Step S4, said step S4 comprises two parts, step S4A and step S4B, which are performed simultaneously, wherein: Step S4A, the control system adjusts the temperature and pressure inside the wet oxidation reactor / kettle (9) to set values, so that the sludge undergoes a sufficient wet catalytic oxidation reaction in the wet oxidation reactor / kettle (9) and forms a carbonized oxidation liquid; Step S4B, the control system discharges part of the gas inside the sludge feed tank (6) through the first pressure relief system (18) to restore the internal pressure of the sludge feed tank (6) to a normal pressure state, and repeats the operations of steps S1 to S2 to pump the next batch of sludge into the sludge feed tank (6) and adjust the sludge feed tank (6) to a high pressure state; Step S5, the control system sends the carbonized oxidation liquid generated after sufficient catalytic oxidation reaction in the wet oxidation reactor / kettle (9) into the separation tank (12) for pressure relief and cooling; Step S6, the carbonized oxidized liquid after cooling is fed into a plate and frame filter press (15) in batches through a feed pump (13) for mechanical dehydration to generate semi-dried carbon cakes, and the lower filtrate generated during dehydration is returned to the front end of the sewage treatment plant through a pipeline for treatment; Step S7, repeating the operations from step S3 to step S6 to perform wet catalytic oxidation treatment on subsequent batches of sludge.

Images