Supercritical water liquefaction-gasification-oxidation coupled system and method for oily sludge

Abstract

The application relates to the technical field of waste resource utilization, and discloses a coupling system and method for supercritical water liquefaction-gasification-oxidation of oily sludge, wherein the coupling reaction device comprises, from the outside to the inside, a supercritical water liquefaction reaction device and a supercritical water oxidation reaction device which are sequentially sleeved; the supercritical water oxidation reaction device is internally provided with a supercritical water gasification reaction spiral device; the supercritical water liquefaction reaction device is communicated with the supercritical water oxidation reaction device through the supercritical water gasification reaction spiral device; the three structures of supercritical water liquefaction, gasification and oxidation are coupled, and the deep treatment of the oily sludge is realized. The supercritical water liquefaction can effectively decompose the organic matters in the sludge, the gasification process converts the organic matters into gas, and the oxidation process ensures the complete removal of the residual pollutants, thereby improving the treatment efficiency and the cleanliness. The organic components in the oily sludge can be effectively converted and utilized, and the conversion from waste to resource is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste resource utilization, in particular to a supercritical water liquefaction-gasification-oxidation coupling system and method for oily sludge. BACKGROUND

[0002] More than five million tons of oily sludge are generated annually in the process of oilfield development and oil processing in China. Oily sludge is a hazardous waste with extremely complex composition, which mainly includes oil (saturated hydrocarbons, aromatic hydrocarbons, resin, and asphaltene), water, and solid substances. In addition, it also contains high concentrations of heavy metals such as copper, zinc, cadmium, and mercury, as well as various microorganisms, including bacteria and pathogenic bacteria. This waste has a stable porous and multiphase structure, which increases the complexity of treatment. Direct discharge of oily sludge can lead to loss of crude oil resources, damage to the natural environment, pollution of water resources, and destruction of soil, and in severe cases, it can damage agricultural production, animal and plant survival, and human life safety. Current mainstream oily sludge treatment technologies include harmless treatment (incineration, solidification, thermal desorption technology, and biological treatment) and resource treatment technology (pyrolysis, extraction, ultrasonic method, mechanical separation method, and thermal chemical cleaning method, etc.). However, both harmless treatment and resource treatment technologies can recover useful components from oily sludge, but they generally have high costs, limited efficiency, secondary pollution risks, resource waste, and narrow application scope. Therefore, in the context of China's sustainable development strategy, there is an urgent need to develop a technology that can effectively treat oily sludge and other waste, achieving clean and efficient resource treatment of oily sludge.

[0003] Supercritical water gasification technology is a new type of thermochemical treatment technology that can convert organic matter into hydrogen-rich gas. This technology takes advantage of the high solubility, low dielectric constant, low viscosity, and high diffusion rate of supercritical water (temperature > 374℃, pressure > 22.1MPa), which can break down the emulsification state of oily sludge, directly dissolve the waste organic matter, separate the oil and ash, form a homogeneous reaction system, and produce high-calorie hydrogen-rich gas. However, after heating in supercritical water direct gasification (600℃-700℃), a portion of the oil tends to volatilize and dissolve in supercritical water, while another portion of the oil tends to remain inside the particles, which may undergo condensation reactions to form coke, hindering the reaction and becoming a key limiting factor in gasification reactions.

[0004] In the supercritical water gasification-oxidation series device for treating oily sludge, the current operation process is to first carry out the gasification reaction (600-700°C) in the gasification device, and then the material enters the oxidation device to carry out the oxidation reaction (900-1000°C) and release a large amount of heat. The existing gasification-oxidation series device does not adopt the technical scheme of coupling gasification and oxidation, resulting in a large amount of heat energy generated in the oxidation stage which must be transferred back to the gasification reaction link through a heat exchanger to realize the reuse of heat energy. Such design causes significant heat loss in the series process from gasification to oxidation, and because the oxidation reaction releases extremely high temperature, it puts extremely strict requirements on the heat exchange equipment, which not only reduces the energy efficiency of the whole system, but also increases the demand for high-performance heat exchange devices.

[0005] In the current supercritical water gasification-oxidation coupling device adopting the sleeve technology, although the gasification reaction device is embedded into the oxidation reaction device to realize direct heat transfer, so that a large amount of heat energy released in the oxidation process can be directly used for gasification reaction, this design brings new problems. Because the gasification reaction is slow, the oxidation reaction is intense and releases high heat, it is extremely difficult to maintain the heat balance between the two reactions. This energy mismatch not only leads to low energy utilization efficiency in the system, causes unnecessary heat loss and waste of resources, but also may cause the system temperature to rise rapidly due to lack of proper regulation, resulting in serious corrosion damage to the reactor, significantly increasing the safety risk of operation, and even may cause safety accidents. In addition, because the gasification reaction is relatively slow, while the oxidation reaction is very rapid, too high temperature may also cause the gasification reaction to fail to proceed fully, and part of the material is oxidized without complete gasification, which not only affects the gasification effect, but also poses a safety hazard to the experimental device. Finally, because the pipeline for supplying oxygen for the oxidation reaction only supplies oxygen from a single point, the oxygen enters immediately causes local intense oxidation reaction, thereby causing uneven heating and incomplete reaction in the reactor.

[0006] The potential value of the hot fluid after the supercritical water liquefaction reaction (380-450°C), supercritical water gasification reaction (600-700°C), and oxidation reaction (900-1000°C) of oily sludge has not been fully tapped. The heat energy of such hot fluid can be effectively utilized for power generation or provided to users for heating, etc. At present, there is a lack of such a system to fully improve energy utilization, promote resource recycling and environmental protection, and promote the transition to a more sustainable energy use mode to achieve a win-win situation of economic, environmental and social benefits. SUMMARY

[0007] In order to overcome the defects of the prior art, the present application aims to provide an oil-containing sludge supercritical water liquefaction-gasification-oxidation coupling system and method to improve the cleaning efficiency of sludge and realize the rational use of resources.

[0008] The present application is realized by the following technical solutions:

[0009] In a first aspect, the present application provides an oil-containing sludge supercritical water liquefaction-gasification-oxidation coupling system, comprising a liquid oxygen output unit, an oil-containing sludge output unit, a water tank, a slag discharge device, a gas-liquid separation unit, a first heat exchanger, and a coupling reaction device.

[0010] The coupling reaction device comprises a supercritical water liquefaction reaction device and a supercritical water oxidation reaction device which are sequentially sleeved from the outside to the inside; the supercritical water oxidation reaction device is provided with a supercritical water gasification reaction spiral device; the supercritical water liquefaction reaction device is in communication with the supercritical water oxidation reaction device through the supercritical water gasification reaction spiral device.

[0011] The supercritical water liquefaction reaction device is provided with a water inlet pipe, a feed pipe, and a slag discharge pipe.

[0012] The output end of the oil-containing sludge output unit is connected to the feed pipe, and the water tank is provided with two output ends, of which the first output end is connected to the oil-containing sludge output unit, and the second output end is provided with two branches, one of which is used to connect to the water inlet pipe after heating; the other branch is connected to the water inlet pipe after passing through the first heat exchanger; and the output end of the slag discharge pipe is connected to the slag discharge device.

[0013] The output end of the liquid oxygen output unit is connected to the input end of the supercritical water oxidation reaction device; the output end of the supercritical water oxidation reaction device is a multi-element heat fluid outlet, which is connected to the input end of the gas-liquid separation unit after passing through the first heat exchanger, and the liquid output end of the gas-liquid separation unit is connected to the water tank; wherein a heat cycle power generation unit or a circulating heat supply system is arranged between the first heat exchanger and the gas-liquid separation unit for respectively performing cycle power generation or cycle heat supply.

[0014] Preferably, the liquid oxygen output unit comprises a liquid oxygen bottle, a liquid oxygen pump, and an air preheater.

[0015] The output end of the liquid oxygen bottle is connected to the input end of the liquid oxygen pump, the output end of the liquid oxygen pump is connected to the input end of the air preheater, and the output end of the air preheater is provided with two groups of branches, and the output ends of the two groups of branches are respectively connected to the input ends of the supercritical water oxidation reaction device.

[0016] Further, the input end of the supercritical water oxidation reaction device comprises a first air inlet plug and a second air inlet plug.

[0017] The input ends of the first and second air inlet nozzles are connected to two groups of branches of the air preheater output end; the output ends of the first and second air inlet nozzles extend into the supercritical water oxidation reaction device, and a plurality of air outlet holes are arranged on the pipe bodies of the first and second air inlet nozzles for outputting oxygen in the supercritical water oxidation reaction device.

[0018] Preferably, the supercritical water gasification reaction spiral device comprises a gasification spiral pipe; the spiral pipe inlet of the gasification spiral pipe is in communication with the supercritical water oxidation reaction device and the supercritical water liquefaction reaction device; and the spiral pipe outlet of the gasification spiral pipe is arranged in the supercritical water oxidation reaction device.

[0019] Preferably, the oily sludge output unit comprises a storage tank, a pulverizer, a mixer and a pump;

[0020] The input end of the storage tank is used for inputting oily sludge, the output end of the storage tank is connected to the input end of the pulverizer, the output end of the pulverizer is connected to the slurry input end of the mixer, the liquid input end of the mixer is connected to the first output end of the water tank; and the output end of the mixer is connected to the feed pipe through the pump.

[0021] Preferably, the second output end of the water tank is provided with a first water pump, and the second output end is provided with two branches after the first water pump, one of the two branches is sequentially provided with a first flow regulating valve and a heating device, and the other branch is provided with a second flow regulating valve, and the two branches are connected to the water inlet pipe after the first heat exchanger.

[0022] Preferably, the gas-liquid separation unit comprises a gas-liquid separator, a gas storage cylinder, a back pressure valve and a first cooler;

[0023] The input end of the back pressure valve is connected to the output end of the first heat exchanger, the output end of the back pressure valve is connected to the input end of the first cooler, the output end of the first cooler is connected to the input end of the gas-liquid separator, the gas output end of the gas-liquid separator is connected to the gas storage cylinder, and the liquid output end of the gas-liquid separator is connected to the water tank;

[0024] The heat cycle power generation unit or the circulating heat supply system is arranged between the first heat exchanger and the back pressure valve, respectively, for performing cycle power generation or cycle heat supply.

[0025] Further, when cycle power generation is performed, the heat cycle power generation unit comprises a second water pump, a second heat exchanger, a turbine and a second cooler;

[0026] The second heat exchanger is provided with two groups of input ends and two groups of output ends, one group of input ends is connected to the output end of the first heat exchanger, and one group of output ends is connected to the input end of the back pressure valve; the other group of output ends is connected to the input end of the heating device, one branch of the output end of the heating device is used for heating the outside world, and the other branch is connected to the input end of the second cooler; the output end of the second cooler is connected to the other group of input ends of the second heat exchanger through the second water pump, forming a circulating heating loop.

[0027] Further, when the circulating heating is carried out, the circulating heating system comprises a second water pump, a second heat exchanger, a heating device and a second cooler.

[0028] The second heat exchanger is provided with two groups of input ends and two groups of output ends, one group of input ends is connected to the output end of the first heat exchanger, and one group of output ends is connected to the input end of the back pressure valve; the other group of output ends is connected to the input end of the heating device, one branch of the output end of the heating device is used for heating the outside world, and the other branch is connected to the input end of the second cooler; the output end of the second cooler is connected to the other group of input ends of the second heat exchanger through the second water pump, forming a circulating heating loop.

[0029] In a second aspect, the application further provides a supercritical water liquefaction-gasification-oxidation coupling method for oily sludge, based on the supercritical water liquefaction-gasification-oxidation coupling system for oily sludge, the coupling method comprising the following steps:

[0030] Water is put into the water tank, and the water is heated through one branch of the water tank and then added to the supercritical water liquefaction reaction device through the water inlet pipe to obtain supercritical water;

[0031] The oily sludge containing sludge is put into the oily sludge output unit, and the water in the water tank is added to the oily sludge output unit for mixing and then added to the supercritical water liquefaction reaction device through the feed pipe;

[0032] Liquid oxygen is added to the liquid oxygen output unit and input to the supercritical water oxidation reaction device through the liquid oxygen output unit;

[0033] The oily sludge and the supercritical water are in the supercritical water liquefaction reaction device, part of the oily sludge is dissolved in the supercritical water, and the supercritical water and the supercritical water gasification reaction spiral device are gasified to obtain a gasification product; another part of the oily sludge, which is not dissolved in the supercritical water, is gravity-settled at the bottom of the supercritical water liquefaction reaction device and enters the residue discharge device through the residue discharge pipe;

[0034] The gasification product and supercritical water enter the supercritical water oxidation reaction device through the supercritical water gasification reaction spiral device to release heat through oxidation reaction, thereby providing heat for the liquefaction reaction in the supercritical water liquefaction reaction device and providing heat for the gasification reaction in the supercritical water gasification reaction spiral device, and multiple heat fluids are generated, which enter the first heat exchanger through the multiple heat fluid outlet of the supercritical water oxidation reaction device;

[0035] The heated branch water flow in the water tank is closed, and another branch of the water tank is opened, so that the water flow of the other branch enters the first heat exchanger and then enters the supercritical water liquefaction reaction device through the water inlet pipe to obtain supercritical water, thereby forming a water heat circulation loop.

[0036] Meanwhile, the multiple heat fluids enter the gas-liquid separation unit after entering the first heat exchanger, and the separated water enters the water tank for water recycling.

[0037] When circulating power generation is performed, the multiple heat fluids are exchanged with the heat circulation power generation unit to form a heat circulation loop, thereby performing circulating power generation to the outside.

[0038] When circulating heating is performed, the multiple heat fluids are exchanged with the circulating heating system to form a circulating heating loop.

[0039] Compared with the prior art, the present application has the following beneficial technical effects:

[0040] The present application provides a supercritical water liquefaction-gasification-oxidation coupling system for oil-containing sludge, which realizes the deep treatment of oil-containing sludge by coupling supercritical water liquefaction, gasification and oxidation. The supercritical water liquefaction can effectively decompose the organic matter in the sludge, the gasification process further converts the organic matter into gas, and the oxidation process ensures the complete removal of the remaining pollutants. This continuous treatment process greatly improves the efficiency and cleanliness of the treatment. The organic components in the oil-containing sludge can be effectively converted and utilized. The liquid product produced in the liquefaction stage contains valuable chemical substances, the gas produced in the gasification stage can be used as energy or chemical raw material, and the oxidation stage ensures the stable operation of the system and the harmless treatment of waste, realizes the conversion from waste to resource, and improves the utilization rate of resources. The present application uses supercritical water as the reaction medium, which can significantly improve the chemical reaction rate and efficiency under certain conditions, while reducing the emission of harmful substances. In addition, the circulating heating and power generation functions in the system further reduce energy consumption and carbon emissions, and realize the rational utilization of resources.

[0041] Further, the liquid oxygen is pressurized by a liquid oxygen pump and preheated into gas by an air preheater, and then uniformly distributed into the input end of the supercritical water oxidation reactor. This process not only improves the reactivity and uniformity of oxygen distribution, but also optimizes energy utilization, enhances system stability and safety, reduces byproduct generation, and improves overall reaction efficiency.

[0042] Further, the input end of the supercritical water oxidation reaction device includes a first gas inlet pipe and a second gas inlet pipe, which are covered with a large number of small gas outlet holes, ensuring multi-point oxygen supply and enabling oxygen to uniformly and fully contact with the reactants, greatly promoting the efficiency of the oxidation reaction. The uniformly dispersed oxygen flow also helps to maintain the stability of the reaction temperature, thereby preventing overheating and potential corrosion problems caused by local intense reactions, significantly improving the efficiency of the entire treatment process while ensuring the safety and reliability of the operation.

[0043] Further, the supercritical water gasification reaction spiral pipe device is designed as a spiral pipe, which increases the contact area to ensure uniform heat distribution, enhances the efficiency of absorbing heat released by the oxidation reaction, maintains thermal balance, and prevents temperature imbalance. If the gasification reaction is performed first and then followed by the oxidation reaction, the entire experimental period will be lengthened. By placing the supercritical water gasification reaction spiral pipe device inside the supercritical water oxidation reaction device, the gasification reaction and oxidation reaction can be performed simultaneously, shortening the experimental period and optimizing the reaction sequence. Due to the use of a long spiral pipe design, the gasification reaction path is greatly extended, increasing the residence time of the oil-containing sludge during the gasification process. This not only ensures that the oil-containing sludge can be completely gasified and prevents coking and pipeline blockage, but also improves the processing efficiency and flexibility, avoiding the problem of insufficient gasification reaction of the oil-containing sludge, and better meeting various production needs.

[0044] Further, the oil-containing sludge in the storage tank is first sent to a pulverizer for fine grinding, turning large particles into small particles. This process significantly increases the specific surface area of the oil-containing sludge, making the subsequent mixing with water more uniform and thorough. Next, these small oil-containing sludge particles are thoroughly mixed with water from the water tank in a mixer to form a uniform slurry. By increasing the contact area between the material and the liquid, not only is the complete fusion of the garbage particles and the liquid ensured, but also ideal conditions are created for supercritical water liquefaction and gasification reactions, improving reaction efficiency and uniformity. This pretreatment method not only reduces energy consumption during the reaction process, but also effectively reduces the risk of pipeline blockage, ensuring stable operation of the system. Finally, through the slurry pump, the prepared slurry can be continuously and stably transported to the supercritical water liquefaction reaction device, ensuring smooth and efficient processing flow.

[0045] Further, the water in the water tank is first pressurized by the first water pump when the system starts operating, enters the heating device through the first flow regulating valve for heating, enters the water inlet pipe, and as the reaction proceeds, the water passes through the second flow regulating valve, enters the first heat exchanger, and then enters the water inlet pipe, and finally enters the supercritical water liquefaction reaction device, forming a hot water circulation loop to achieve hot water circulation, so that heating is no longer needed. Therefore, in order to ensure the stability of the water quantity and pressure, the second flow regulating valve should be gradually opened while the first flow regulating valve is gradually closed. This ensures that the degree of closing the first flow regulating valve matches the degree of opening the second flow regulating valve, maintaining the continuity of the water flow and the constancy of the system pressure. This ensures that there is no sudden change in flow or pressure during the transition process, achieving a smooth transition; therefore, the heating device can be turned off in the follow-up, and only heat exchange and water are used, maximizing the use of heat energy and reducing resource waste.

[0046] Further, by introducing the gas-liquid separator, the gas and liquid generated during the treatment process can be efficiently separated; the introduction of the back pressure valve can adjust the pressure in the system, thereby controlling the temperature and pressure of the gas to meet the needs of the subsequent treatment steps. The first cooler not only cools the gas, but also releases heat energy during the cooling process. These heat energies can be effectively utilized by the heat cycle power generation unit or the circulating heating system, thereby further improving the energy utilization efficiency of the system. The heat cycle power generation unit is set to enable the system to generate electricity using the heat energy generated during the treatment process to provide power support for the system or other equipment. This helps to reduce the operating cost of the system and improve the overall economic benefit. The circulating heating system can use heat energy for heating, hot water supply and other purposes to meet the heat energy needs of the surrounding areas or enterprises. This multi-purpose energy utilization method further improves the flexibility and practicality of the system.

[0047] Further, the turbine, as a key device for converting heat energy, can convert high-temperature and high-pressure heat energy into mechanical energy, which in turn drives the generator to generate electricity. In this process, heat energy is efficiently utilized and converted into electrical energy to provide power support for the system or other equipment, reducing dependence on traditional energy sources. Through the synergistic action of the second heat exchanger, the second water pump and the second cooler, a closed heat circulation loop is formed. This loop ensures the continuous flow and efficient utilization of heat energy within the system, avoiding waste of heat energy.

[0048] Further, the circulating heat supply system can fully utilize the heat energy generated during the treatment of oil-containing sludge. The heat energy is transferred to the heat supply device through the second heat exchanger, and then the heat supply device supplies heat to the outside. This process realizes efficient utilization of heat energy and avoids waste of heat energy. The heat supply device can adjust the heat supply power according to the actual demand to ensure stable supply of heat energy and meet the heat supply demand of the surrounding area or enterprise. Through the cooperation of the second water pump, the second heat exchanger and the second cooler, a closed circulating heat supply loop is formed. This loop ensures the continuous flow and effective utilization of heat energy in the system, improving the utilization efficiency of heat energy.

[0049] The application also provides a coupling method for supercritical water liquefaction-gasification-oxidation of oil-containing sludge. The excellent physicochemical properties of supercritical water are utilized, and supercritical water liquefaction, gasification and oxidation technologies are adopted to realize efficient and clean conversion of oil-containing sludge and clean conversion and efficient utilization of materials. In this process, a large amount of heat energy is released by the oxidation reaction. These energies not only meet the heat demand of the treatment process itself, but also can be further converted into electric energy or other forms of energy, significantly improving the resource utilization efficiency and energy recovery rate. The multi-element heat fluid generated by liquefaction, gasification and oxidation enters the first heat exchanger and exchanges heat with the water in the water tank, and then is introduced into the supercritical water gasification reaction device to complete the water circulation. At the same time, the circulating power generation device is used for heat exchange to realize energy recovery and power generation, forming a closed-loop energy utilization system. After two heat exchanges, the multi-element heat fluid then flows into the gas-liquid separator, and in this process, the multi-element heat fluid is separated into hydrogen-rich gas and liquid. The hydrogen-rich gas is stored in the gas cylinder for subsequent use, retaining the high-value hydrogen resource, while the separated liquid is returned to the water tank, realizing resource recycling, improving energy utilization and reducing environmental pollution. This integrated design not only improves the overall energy efficiency of the system, but also promotes effective resource management and environmental protection, ensuring the sustainability and economic benefits of the whole process. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 FIG. 1 is a structural schematic diagram of the coupling system in embodiment 1 of the application;

[0051] Figure 2 FIG. 2 is a structural schematic diagram of the coupling system in embodiment 2 of the application;

[0052] Figure: 1, liquid oxygen bottle; 2, liquid oxygen pump; 3, air preheater; 4, storage tank; 5, pulverizer; 6, mixer; 7, material pump; 8, water tank; 9, first water pump; 10, heating device; 11, second water pump; 12, water inlet pipe; 13, material inlet pipe; 14, first air inlet pipe; 15, second air inlet pipe; 16, multi-element heat fluid outlet; 17, spiral pipe inlet; 18, spiral pipe outlet; 19, slag discharge pipe; 20, slag discharge device; 21, supercritical water liquefaction reaction device; 22, supercritical water oxidation reaction device; 23, gasification spiral pipe; 24, gas-liquid separator; 25, gas storage bottle; 26, first heat exchanger; 27, second heat exchanger; 28, back pressure valve; 29, first cooler; 30, turbine; 31, second cooler; 32, supercritical water gasification reaction spiral device; 33, first flow regulating valve; 34, second flow regulating valve; 35, heat supply device. DETAILED DESCRIPTION

[0053] In order to make the personnel in the technical field better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0054] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0055] The purpose of the present application is to provide a supercritical water liquefaction-gasification-oxidation coupling system and method for oily sludge, to solve the technical problem of how to improve the cleaning efficiency of sludge in the prior art, so as to realize the rational use of resources.

[0056] The present application will be described in further detail below in combination with the drawings:

[0057] Example 1

[0058] Reference Figure 1 andFigure 2 In this embodiment 1, a supercritical water liquefaction-gasification-oxidation coupling system for oily sludge is provided, which comprises a liquid oxygen output unit, an oily sludge output unit, a water tank 8, a slag discharge device 20, a gas-liquid separation unit, a first heat exchanger 26 and a coupling reaction device; the coupling reaction device comprises a supercritical water liquefaction reaction device 21 and a supercritical water oxidation reaction device 22 which are sequentially sleeved from outside to inside; the supercritical water oxidation reaction device 22 is provided with a supercritical water gasification reaction spiral device 32; the supercritical water liquefaction reaction device 21 is in communication with the supercritical water oxidation reaction device 22 through the supercritical water gasification reaction spiral device 32; the supercritical water liquefaction reaction device 21 is provided with a water inlet pipe 12, a feed pipe 13 and a slag discharge pipe 19; the output end of the oily sludge output unit is connected to the feed pipe 13, and the water tank 8 is provided with two output ends, wherein the first output end is connected to the oily sludge output unit; the second output end is provided with two branches, one of which is used to connect to the water inlet pipe 12 after heating; the other branch is connected to the water inlet pipe 12 after passing through the first heat exchanger 26; the output end of the slag discharge pipe 19 is connected to the slag discharge device 20; the output end of the liquid oxygen output unit is connected to the input end of the supercritical water oxidation reaction device 22; the output end of the supercritical water oxidation reaction device 22 is a multi-element heat fluid outlet 16, which is connected to the input end of the gas-liquid separation unit after passing through the first heat exchanger 26, and the liquid output end of the gas-liquid separation unit is connected to the water tank 8; wherein a heat circulation power generation unit or a circulating heat supply system is provided between the first heat exchanger 26 and the gas-liquid separation unit for circulating power generation or circulating heat supply, respectively.

[0059] Specifically, the liquid oxygen output unit comprises a liquid oxygen bottle 1, a liquid oxygen pump 2 and an air preheater 3; the output end of the liquid oxygen bottle 1 is connected to the input end of the liquid oxygen pump 2, the output end of the liquid oxygen pump 2 is connected to the input end of the air preheater 3, and the output end of the air preheater 3 is divided into two groups of branches, and the output ends of the two groups of branches are respectively connected to the input ends of the supercritical water oxidation reaction device 22.

[0060] In this embodiment, the liquid oxygen bottle 1 is a container for storing liquid oxygen, which can maintain the stable storage of liquid oxygen under low temperature conditions. When liquid oxygen is needed, the output end of the liquid oxygen bottle 1 will be opened, and the liquid oxygen will be transported to the liquid oxygen pump 2 through the pipeline. The liquid oxygen pump 2 is the core equipment in the liquid oxygen output unit, which functions to extract liquid oxygen from the liquid oxygen bottle 1 and deliver it to the air preheater 3 after pressurization. The main function of the air preheater 3 is to preheat the liquid oxygen entering the supercritical water oxidation reaction device 22.

[0061] The input end of the supercritical water oxidation reaction device 22 comprises a first air inlet pipe 14 and a second air inlet pipe 15; the input ends of the first air inlet pipe 14 and the second air inlet pipe 15 are respectively connected to two groups of branches of the output end of the air preheater 3; the output ends of the first air inlet pipe 14 and the second air inlet pipe 15 extend into the supercritical water oxidation reaction device 22, and a plurality of air outlet holes are respectively arranged on the pipe bodies of the first air inlet pipe 14 and the second air inlet pipe 15 for outputting oxygen in the supercritical water oxidation reaction device 22.

[0062] In the embodiment, the output ends of the first air inlet pipe 14 and the second air inlet pipe 15 extend into the supercritical water oxidation reaction device 22, and a plurality of air outlet holes are respectively arranged on the pipe bodies. The air outlet holes are used for uniformly outputting oxygen in the supercritical water oxidation reaction device 22, so as to ensure that the oxygen can be fully mixed with supercritical water and organic matter, thereby performing efficient oxidation reaction.

[0063] Specifically, the supercritical water gasification reaction spiral device 32 comprises a gasification spiral pipe 23; the spiral pipe inlet 17 of the gasification spiral pipe 23 is communicated with the supercritical water liquefaction reaction device 21 through the supercritical water oxidation reaction device 22; and the spiral pipe outlet 18 of the gasification spiral pipe 23 is arranged in the supercritical water oxidation reaction device 22.

[0064] In the embodiment, the gasification spiral pipe 23 is designed by using the unique structure of the spiral pipe, which can enhance the flow and heat transfer efficiency of the fluid in the pipe. In the spiral pipe, due to the centrifugal force generated by the bending of the pipe, the fluid at the center of the pipe flows to the outside of the pipe; at the same time, the fluid close to the outer wall surface flows along the two side walls to the inside under the influence of the pressure gradient, and the fluid after converging at the inside of the pipe flows to the outer wall side along the horizontal line of the cross section center of the pipe, so that two basically symmetrical vortexes are formed in the pipe. This flow mode helps to enhance the heat transfer efficiency between the fluid and the pipe wall.

[0065] Specifically, the oil-containing sludge output unit comprises a storage tank 4, a pulverizer 5, a mixer 6 and a material pump 7; the input end of the storage tank 4 is used for inputting oil-containing sludge, the output end of the storage tank 4 is connected to the input end of the pulverizer 5, the output end of the pulverizer 5 is connected to the slurry input end of the mixer 6, and the liquid input end of the mixer 6 is connected to the first output end of the water tank 8; and the output end of the mixer 6 is connected to the feeding pipe 13 through the material pump 7.

[0066] In this embodiment, the main function of the storage tank 4 is to store the input oily sludge, ensuring sufficient sludge supply during the treatment process. The pulverizer 5 is used to pulverize the oily sludge output from the storage tank 4, reducing its particle size for subsequent mixing and conveying. The mixer 6 is used to mix the pulverized oily sludge with water from the water tank 8 to form a uniform slurry. The pump 7 is used to convey the mixed slurry output from the mixer 6 through the feed pipe 13 into the supercritical water liquefaction reaction device 21.

[0067] Specifically, the second output end of the water tank 8 is provided with a first water pump 9, and the second output end is provided with two branches after the first water pump 9, one of which is provided with a first flow regulating valve 33 and a heating device 10 in sequence, used for heating and connecting to the water inlet pipe 12; the other branch is provided with a second flow regulating valve 34, used for connecting to the water inlet pipe 12 after the first heat exchanger 26.

[0068] In this embodiment, when the system starts to work, the water in the water tank 8 is first pressurized by the first water pump 9, heated by the heating device 10 through the first flow regulating valve 33, enters the water inlet pipe 12, and as the reaction proceeds, the water passes through the second flow regulating valve 34, enters the first heat exchanger 26, then enters the water inlet pipe 12, and finally enters the supercritical water liquefaction reaction device 21, forming a hot water circulation loop to achieve hot water circulation, so that heating is no longer needed. Therefore, in order to ensure the stability of the water quantity and pressure, the second flow regulating valve 34 should be gradually opened while the first flow regulating valve 33 is gradually closed. This ensures that the degree of closing the first flow regulating valve 33 matches the degree of opening the second flow regulating valve 34, maintaining the continuity of the water flow and the constancy of the system pressure. This can ensure that there is no sudden change in flow or pressure during the transition, achieving a smooth transition; therefore, the heating device 10 can be turned off in the subsequent process, only using heat exchange and water, maximizing the use of heat energy and reducing resource waste.

[0069] Specifically, the gas-liquid separation unit includes a gas-liquid separator 24, a gas storage cylinder 25, a back pressure valve 28, and a first cooler 29; the input end of the back pressure valve 28 is connected to the output end of the first heat exchanger 26, the output end of the back pressure valve 28 is connected to the input end of the first cooler 29, the output end of the first cooler 29 is connected to the input end of the gas-liquid separator 24, the gas output end of the gas-liquid separator 24 is connected to the gas storage cylinder 25, and the liquid output end of the gas-liquid separator 24 is connected to the water tank 8; the heat circulation power generation unit or the circulating heat supply system is respectively arranged between the first heat exchanger 26 and the back pressure valve 28, for respectively performing circulating power generation or circulating heat supply.

[0070] In this embodiment, by introducing a gas-liquid separator 24, the gas and liquid generated during the processing can be efficiently separated; the introduction of a back pressure valve 28 can regulate the pressure within the system, thereby controlling the temperature and pressure of the gas to meet the needs of subsequent processing steps. The first cooler 29 not only cools the gas but also releases heat energy during the cooling process. This heat energy can be effectively utilized by a thermal cycle power generation unit or a circulating heating system, thereby further improving the system's energy efficiency.

[0071] The back pressure valve 28 ensures the stable, efficient and safe operation of the fluid system by maintaining minimum operating pressure, preventing backflow, controlling flow and pressure fluctuations, promoting bubble discharge, assisting reaction conditions and providing safety protection.

[0072] Among them, according to Figure 1 As shown, when performing cyclic power generation, the thermal cycle power generation unit includes a second water pump 11, a second heat exchanger 27, a turbine 30, and a second cooler 31. The second heat exchanger 27 has two sets of input terminals and two sets of output terminals. One set of input terminals is connected to the output terminal of the first heat exchanger 26, and the other set of output terminals is connected to the input terminal of the back pressure valve 28. The other set of output terminals is connected to the input terminal of the turbine 30. One branch of the output terminal of the turbine 30 is used to generate electricity to the outside world, and the other branch is connected to the input terminal of the second cooler 31. The output terminal of the second cooler 31 is connected to the other set of input terminals of the second heat exchanger 27 after passing through the second water pump 11, forming a thermal cycle loop.

[0073] In this embodiment, the turbine 30, as a key device for heat energy conversion, can convert high-temperature, high-pressure heat energy into mechanical energy, thereby driving a generator to produce electricity. In this process, heat energy is efficiently utilized and converted into electrical energy, providing power support for the system or other equipment, reducing dependence on traditional energy sources. Through the synergistic action of the second heat exchanger 27, the second water pump 11, and the second cooler 31, a closed thermal cycle loop is formed. This loop ensures the continuous flow and effective utilization of heat energy within the system, avoiding waste of heat energy.

[0074] Among them, according to Figure 2 As shown, when circulating heating is performed, the circulating heating system includes a second water pump 11, a second heat exchanger 27, a heating device 35, and a second cooler 31.

[0075] The second heat exchanger 27 is provided with two groups of input ends and two groups of output ends, one group of input ends is connected to the output end of the first heat exchanger 26, and one group of output ends is connected to the input end of the back pressure valve 28; the other group of output ends is connected to the input end of the heating device 35, and one branch of the output end of the heating device 35 is used for heating the outside world, and the other branch is connected to the input end of the second cooler 31, and the output end of the second cooler 31 is connected to the other group of input ends of the second heat exchanger 27 through the second water pump 11, forming a circulating heating loop.

[0076] In this embodiment, the circulating heating system can fully utilize the heat energy generated during the treatment of oily sludge, which is transferred to the heating device 35 through the second heat exchanger 27, and then used for heating the outside world. This process realizes efficient utilization of heat energy and avoids waste of heat energy. The heating device 35 can adjust the heating power according to actual needs to ensure stable supply of heat energy and meet the heating needs of surrounding areas or enterprises. Through the cooperation of the second water pump 11, the second heat exchanger 27 and the second cooler 31, a closed circulating heating loop is formed. This loop ensures the continuous flow and effective utilization of heat energy in the system, improving the utilization efficiency of heat energy.

[0077] In summary, the embodiment provides a coupling system for supercritical water liquefaction-gasification-oxidation of oily sludge, which realizes deep treatment of oily sludge by coupling supercritical water liquefaction, gasification and oxidation. Supercritical water liquefaction can effectively decompose organic matter in sludge, the gasification process further converts organic matter into gas, and the oxidation process ensures complete removal of residual pollutants. This continuous treatment process greatly improves the efficiency and cleanliness of the treatment. The organic components in the oily sludge can be effectively converted and utilized. The liquid product produced in the liquefaction stage contains valuable chemicals, the gas produced in the gasification stage can be used as energy or chemical raw material, and the oxidation stage ensures stable operation of the system and harmless treatment of waste, realizing the conversion from waste to resource and improving the utilization rate of resources. The present application uses supercritical water as the reaction medium, which can significantly improve the chemical reaction rate and efficiency under certain conditions, while reducing the emission of harmful substances. In addition, the circulating heating and power generation functions in the system further reduce energy consumption and carbon emissions, realizing the rational utilization of resources.

[0078] Embodiment 2

[0079] Referring to Figure 1 and Figure 2 In this embodiment 2, a coupling method for supercritical water liquefaction-gasification-oxidation of oily sludge is provided, based on the above-mentioned coupling system for supercritical water liquefaction-gasification-oxidation of oily sludge, the coupling method comprises the following steps:

[0080] Water is placed in the water tank 8, and the water enters the first water pump 9, pressurized to more than 22.1 MPa, enters the first flow regulating valve 33, and then enters the heating device 10 for heating. After heating, the water enters the water inlet pipe 12 and is added to the supercritical water liquefaction reaction device 21 to obtain supercritical water;

[0081] The oil-containing sludge is placed in the storage tank 4, which is crushed in the crusher 5 and placed in the blender 6. The water in the water tank 8 is added to the blender 6 and mixed with the oil-containing sludge, enters the material pump 7, and is added to the supercritical water liquefaction reaction device 21 through the feed pipe 13;

[0082] The liquid oxygen in the liquid oxygen bottle 1 is pumped by the liquid oxygen pump 2 into the air preheater 3, and the gas enters the first gas inlet nozzle 14 and the second gas inlet nozzle 15 through the gas holes of the first gas inlet nozzle 14 and the second gas inlet nozzle 15, and is added to the supercritical water oxidation reaction device 22;

[0083] The oil-containing sludge and supercritical water are in the supercritical water liquefaction reaction device 21, part of the oil-containing sludge is dissolved in the supercritical water, and the supercritical water is gasified in the supercritical water gasification reaction spiral device 32 (600-700℃) to obtain gasification products; another part of the oil-containing sludge that is not dissolved in the supercritical water is settled at the bottom of the supercritical water liquefaction reaction device 21 by gravity, and enters the slag discharge device 20 through the slag discharge pipe 19;

[0084] The gasification products and supercritical water pass through the supercritical water gasification reaction spiral device 32 into the supercritical water oxidation reaction device 22 to undergo oxidation reaction (900-1000℃) to release heat, which provides heat for the liquefaction reaction (380-450℃) in the supercritical water liquefaction reaction device 21 and the gasification reaction (600-700℃) in the supercritical water gasification reaction spiral device 32, producing multi-element heat fluid, which enters the first heat exchanger 26 through the multi-element heat fluid outlet 16 of the supercritical water oxidation reaction device 22;

[0085] The water in the water tank 8 enters the first water pump 9, and in order to ensure the stability of the water quantity and pressure, the second flow regulating valve 34 should be gradually opened while the first flow regulating valve 33 is gradually closed. Each adjustment in this process requires precise control to ensure that the degree of closing the first flow regulating valve 33 matches the degree of opening the second flow regulating valve 34, so as to maintain the continuity of the water flow and the constancy of the system pressure. This ensures that there is no sudden change in flow or pressure during the transition process, achieving a smooth transition; the water passes through the second flow regulating valve 34, enters the first heat exchanger 26, then enters the water inlet pipe 12, and finally enters the supercritical water liquefaction reaction device 21, forming a water heat circulation loop;

[0086] The multi-element heat fluid enters the first heat exchanger 26 and the second heat exchanger 27, passes through the back pressure valve 28, is cooled in the first cooler 29, enters the gas-liquid separator 24, and the separated hydrogen-rich gas enters the gas cylinder 25, and the separated water enters the water tank 8, realizing water recycling;

[0087] When the circulating power generation is performed, the multi-element heat fluid exchanges heat with the heat circulating power generation unit through the second heat exchanger 27, and then sequentially passes through the turbine 30 and the second cooler 31, reaches the second water pump 11, and returns to the second heat exchanger 27 for heat exchange, forming a heat circulating loop and realizing the circulating power generation.

[0088] When the circulating heating is performed, the multi-element heat fluid exchanges heat with the heat circulating power generation unit through the second heat exchanger 27, and then sequentially passes through the heating device 35 and the second cooler 31, reaches the second water pump 11, and returns to the second heat exchanger 27 for heat exchange, forming a circulating heating loop.

[0089] In summary, the oil-containing sludge supercritical water liquefaction-gasification-oxidation coupling method provided by the embodiment utilizes the excellent physicochemical properties of supercritical water, uses supercritical water liquefaction, gasification, and oxidation technologies, realizes efficient and clean conversion of oil-containing sludge, and realizes clean conversion and efficient utilization of materials. In this process, a large amount of heat energy is released by the oxidation reaction, which not only meets the heat demand of the treatment process itself, but also can be further converted into electric energy or other forms of energy, significantly improving resource utilization efficiency and energy recovery rate. The multi-element heat fluid generated by liquefaction, gasification, and oxidation enters the first heat exchanger 26 and the second heat exchanger 27 in turn, can exchange heat with the water in the water tank 8, and then is introduced into the supercritical water gasification reaction device to complete water circulation. At the same time, the circulating power generation device is used for heat exchange, realizing energy recovery and power generation, forming a closed-loop energy utilization system. The multi-element heat fluid after two heat exchanges then flows into the gas-liquid separator 24, and in this process, the multi-element heat fluid is separated into hydrogen-rich gas and liquid. The hydrogen-rich gas is stored in the gas cylinder 25 for subsequent use, retaining high-value hydrogen resources, while the separated liquid is returned to the water tank 8, realizing resource recycling, improving energy utilization rate, and reducing environmental pollution. This integrated design not only improves the overall energy efficiency of the system, but also promotes effective resource management and environmental protection, ensuring the sustainability and economic benefits of the entire process.

[0090] The supercritical water liquefaction reaction device 21, the supercritical water gasification reaction spiral tube device, and the supercritical water oxidation reaction device 22 are coupled together through a sleeve structure. The supercritical water liquefaction reaction device 21 is in the outermost layer, the supercritical water oxidation reaction device 22 is in the innermost layer, and the supercritical water gasification reaction spiral tube device is inside the supercritical water oxidation reaction device 22. This arrangement ensures the continuous operation of the experiment. The supercritical water oxidation reaction device 22 is oxidized and exothermic (900-1000°C), which directly transfers heat to the supercritical water liquefaction reaction device (380-450°C) and the supercritical water gasification reaction spiral tube device (600-700°C) through the wall surface, shortens the time for the reaction to reach the desired temperature, reduces the use of heat exchangers, effectively reduces costs, avoids heat loss, and realizes energy recycling. At the same time, the direct heat transfer technology helps to reduce the energy loss of the system, accelerate the temperature rise of the reaction, and thus enhance the energy efficiency of the system. In addition, this method can effectively prevent local overheating in the supercritical water oxidation reaction device 22, avoid the serious corrosion of the reactor and potential safety accidents caused thereby, and thus ensure the stable and safe operation of the system.

[0091] Supercritical water has adjustable physicochemical properties. The oil phase in the oily sludge is efficiently extracted into the supercritical water phase using the thermal solvent effect of supercritical water near the critical point (380-450°C), realizing oil-solid separation. The supercritical water liquefaction reaction device 21 effectively solves the key problems in the treatment of oily sludge. When the oily sludge is heated in supercritical water, a part of the oil components is easily volatilized and dissolved in supercritical water, while the oil that is not easily dissolved tends to remain inside the particles and may undergo condensation to form coke, which will hinder the reaction. By using the supercritical water liquefaction reaction technology (380-450°C), the effective separation and conversion of oil (saturated hydrocarbons, aromatic hydrocarbons, resins, asphaltenes, etc.) can be realized: the oil is completely dissolved in supercritical water, and the particles that are not dissolved in supercritical water are converted into a more easily handled form. The unreacted particulate matter settles at the bottom of the reactor, realizing oil-solid separation. This method not only improves the efficiency and safety of oily sludge treatment, promotes resource recycling, but also prevents problems such as coking, insufficient gasification reaction, and pipeline blockage caused by directly gasifying the oily sludge. The supercritical water liquefaction reaction device 21 is connected to the slag discharge device 20, which not only can directly collect particulate matter and prevent residual effects on the experiment, but also can improve system stability, prolong equipment life, optimize reaction conditions, enhance safety, and promote resource recovery, while simplifying the operation process, realizing efficient, safe, and environmentally friendly operation.

[0092] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or equivalently replaced without departing from the spirit and scope of the present application, and any modification or equivalent replacement should be covered within the protection scope of the present application.

Claims

1. A supercritical water liquefaction-gasification-oxidation coupled system for oil-containing sludge, characterized in that, The coupling reaction device comprises, from outside to inside, a supercritical water liquefaction reaction device (21) and a supercritical water oxidation reaction device (22) which are sequentially sleeved; the supercritical water oxidation reaction device (22) is internally provided with a supercritical water gasification reaction spiral device (32); the supercritical water liquefaction reaction device (21) is in communication with the supercritical water oxidation reaction device (22) through the supercritical water gasification reaction spiral device (32); The supercritical water liquefaction reaction device (21) is provided with a water inlet pipe (12), a feed pipe (13) and a residue discharge pipe (19); The output end of the oil-containing sludge output unit is connected to the feed pipe (13), and the water tank (8) is provided with two output ends, wherein the first output end is connected to the oil-containing sludge output unit; the second output end is provided with two branches, one of which is used to be connected to the water inlet pipe (12) after being heated; the other branch is connected to the water inlet pipe (12) after passing through the first heat exchanger (26); and the output end of the residue discharge pipe (19) is connected to the residue discharge device (20); The output end of the liquid oxygen output unit is connected to the input end of the supercritical water oxidation reaction device (22); the output end of the supercritical water oxidation reaction device (22) is a multi-element heat fluid outlet (16), which is connected to the input end of the gas-liquid separation unit after passing through the first heat exchanger (26), and the liquid output end of the gas-liquid separation unit is connected to the water tank (8); wherein a heat cycle power generation unit or a circulating heat supply system is arranged between the first heat exchanger (26) and the gas-liquid separation unit, for respectively performing cycle power generation or cycle heat supply; The supercritical water gasification reaction spiral device (32) comprises a gasification spiral pipe (23); wherein the spiral pipe inlet (17) of the gasification spiral pipe (23) is in communication with the supercritical water liquefaction reaction device (21) through the supercritical water oxidation reaction device (22); and the spiral pipe outlet (18) of the gasification spiral pipe (23) is arranged in the supercritical water oxidation reaction device (22); The gas-liquid separation unit comprises a gas-liquid separator (24), a gas storage cylinder (25), a back pressure valve (28) and a first cooler (29); The input end of the back pressure valve (28) is connected to the output end of the first heat exchanger (26), the output end of the back pressure valve (28) is connected to the input end of the first cooler (29), the output end of the first cooler (29) is connected to the input end of the gas-liquid separator (24), the gas output end of the gas-liquid separator (24) is connected to the gas storage cylinder (25), and the liquid output end of the gas-liquid separator (24) is connected to the water tank (8); The heat cycle power generation unit or the circulating heat supply system is arranged between the first heat exchanger (26) and the back pressure valve (28); When cycle power generation is performed, the heat cycle power generation unit comprises a second water pump (11), a second heat exchanger (27), a turbine (30) and a second cooler (31); ​ The second heat exchanger (27) is provided with two groups of input ends and two groups of output ends, one group of input ends is connected to the output end of the first heat exchanger (26), and one group of output ends is connected to the input end of the back pressure valve (28); the other group of output ends is connected to the input end of the turbine (30), one branch of the output end of the turbine (30) is used for power generation to the outside world, and the other branch is connected to the input end of the second cooler (31), the output end of the second cooler (31) is connected to the other group of input ends of the second heat exchanger (27) through the second water pump (11), forming a heat circulation loop; When the circulating heating is carried out, the circulating heating system comprises the second water pump (11), the second heat exchanger (27), the heating device (35) and the second cooler (31); The second heat exchanger (27) is provided with two groups of input ends and two groups of output ends, one group of input ends is connected to the output end of the first heat exchanger (26), and one group of output ends is connected to the input end of the back pressure valve (28); the other group of output ends is connected to the input end of the heating device (35), one branch of the output end of the heating device (35) is used for heating to the outside world, and the other branch is connected to the input end of the second cooler (31), the output end of the second cooler (31) is connected to the other group of input ends of the second heat exchanger (27) through the second water pump (11), forming a circulating heating loop.

2. The supercritical water liquefaction-gasification-oxidation coupled system for oil-containing sludge according to claim 1, characterized in that, The liquid oxygen output unit comprises a liquid oxygen bottle (1), a liquid oxygen pump (2) and an air preheater (3); The output end of the liquid oxygen bottle (1) is connected to the input end of the liquid oxygen pump (2), the output end of the liquid oxygen pump (2) is connected to the input end of the air preheater (3), and the output end of the air preheater (3) is provided with two groups of branches, and the output ends of the two groups of branches are respectively connected to the input ends of the supercritical water oxidation reaction device (22).

3. The supercritical water liquefaction-gasification-oxidation coupled system for oil-containing sludge according to claim 2, characterized in that, The input end of the supercritical water oxidation reaction device (22) comprises a first air inlet pipe (14) and a second air inlet pipe (15); The input ends of the first air inlet pipe (14) and the second air inlet pipe (15) are respectively connected to the two groups of branches of the output end of the air preheater (3); the output ends of the first air inlet pipe (14) and the second air inlet pipe (15) are arranged in the supercritical water oxidation reaction device (22), and a plurality of air outlet holes are respectively arranged on the pipe bodies of the first air inlet pipe (14) and the second air inlet pipe (15) for outputting oxygen in the supercritical water oxidation reaction device (22).

4. The supercritical water liquefaction-gasification-oxidation coupled system for oil-containing sludge according to claim 1, characterized in that, The oil-containing sludge output unit comprises a storage tank (4), a pulverizer (5), a mixer (6) and a material pump (7); The input end of the storage tank (4) is used for inputting oil-containing sludge, the output end of the storage tank (4) is connected to the input end of the pulverizer (5), the output end of the pulverizer (5) is connected to the slurry input end of the mixer (6), the liquid input end of the mixer (6) is connected to the first output end of the water tank (8); the output end of the mixer (6) is connected to the feeding pipe (13) through the material pump (7).

5. The supercritical water liquefaction-gasification-oxidation coupled system for oil-containing sludge according to claim 1, characterized in that, The second output end of the water tank (8) is provided with a first water pump (9), and the second output end is provided with two branches after the first water pump (9), one of which is provided with a first flow regulating valve (33) and a heating device (10) in sequence, and is connected to the water inlet pipe (12) after heating; the other branch is provided with a second flow regulating valve (34), and is connected to the water inlet pipe (12) after passing through the first heat exchanger (26).

6. A method for supercritical water liquefaction-gasification-oxidation coupling of oil-containing sludge, characterized by, The coupling system for supercritical water liquefaction-gasification-oxidation of oil-containing sludge according to any one of claims 1-5, the coupling method comprising the following steps: Put water into the water tank (8), and heat the water through one branch of the water tank (8) and then add it to the supercritical water liquefaction reaction device (21) through the water inlet pipe (12) to obtain supercritical water; Put the oil-containing sludge into the oil-containing sludge output unit, mix the water in the water tank (8) with the oil-containing sludge in the oil-containing sludge output unit, and then add it to the supercritical water liquefaction reaction device (21) through the feed pipe (13); Add liquid oxygen to the liquid oxygen output unit, and input it to the supercritical water oxidation reaction device (22) through the liquid oxygen output unit; The oil-containing sludge and the supercritical water are in the supercritical water liquefaction reaction device (21), part of the oil-containing sludge is dissolved in the supercritical water, and the supercritical water and the gasification product are in the supercritical water gasification reaction spiral device (32) for gasification reaction; the other part of the oil-containing sludge which is not dissolved in the supercritical water is settled at the bottom of the supercritical water liquefaction reaction device (21) by gravity, and enters the residue discharge device (20) through the residue discharge pipe (19); The gasification product and the supercritical water pass through the supercritical water gasification reaction spiral device (32) and enter the supercritical water oxidation reaction device (22) for oxidation reaction to release heat, which provides heat for the liquefaction reaction in the supercritical water liquefaction reaction device (21) and the gasification reaction in the supercritical water gasification reaction spiral device (32), and generates a multi-element heat fluid which enters the first heat exchanger (26) through the multi-element heat fluid outlet (16) of the supercritical water oxidation reaction device (22); Close the water flow of one branch of the water tank (8) which is heated, and open the other branch of the water tank, so that the water flow of the other branch enters the first heat exchanger (26) and then enters the supercritical water liquefaction reaction device (21) through the water inlet pipe (12) to obtain supercritical water, forming a water heat circulation loop; At the same time, the multi-element heat fluid enters the gas-liquid separation unit after entering the first heat exchanger (26), and the separated water enters the water tank (8) for water recycling; When circulating power generation is performed, the multi-element heat fluid exchanges heat with the heat circulation power generation unit to form a heat circulation loop for circulating power generation to the outside world; When circulating heating is performed, the multi-element heat fluid exchanges heat with the circulating heating system to form a circulating heating loop.

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