Oily sludge supercritical water liquefaction-gasification-oxidation coupling system and method

Abstract

The invention relates to the technical field of waste resource utilization, and discloses a supercritical water liquefaction-gasification-oxidation coupling system and method for oily sludge, and a coupling reaction device in the system comprises a supercritical water liquefaction reaction device and a supercritical water oxidation reaction device which are sequentially sleeved from outside to inside; a supercritical water gasification reaction spiral device is arranged in the supercritical water oxidation reaction device; the supercritical water liquefaction reaction device is communicated with the supercritical water oxidation reaction device through the supercritical water gasification reaction spiral device; by coupling the supercritical water liquefaction structure, the gasification structure and the oxidation structure, the deep treatment of the oily sludge is realized. The supercritical water liquefaction can effectively decompose organic matters in the sludge, the organic matters are converted into gas in the gasification process, the oxidation process ensures thorough removal of residual pollutants, and the treatment efficiency and cleanliness are improved. Organic components in the oily sludge can be effectively converted and utilized, so that the conversion from wastes to resources is realized.

Description

Technical Field

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

[0002] my country produces more than five million tons of oily sludge every year during oilfield development and oil processing. Oily sludge is a hazardous waste with extremely complex components, mainly composed of oil (saturated hydrocarbons, aromatic hydrocarbons, colloids, asphaltene), water and solid matter. In addition, it also contains high concentrations of heavy metals such as copper, zinc, cadmium and mercury; various microorganisms, including bacteria and pathogens. This waste has a stable porous multiphase structure, which increases the complexity of treatment. If oily sludge is directly discharged, it will lead to the loss of crude oil resources, the destruction of the natural environment, water resource pollution, soil damage, etc. In severe cases, it will damage agricultural production, the survival of animals and plants, and human life safety. The 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 and thermochemical cleaning, etc.). However, although harmless treatment and resource treatment technologies can recycle the useful components in oily sludge, they generally have problems such as high cost, limited efficiency, secondary pollution risk, waste of resources and narrow scope of application. Therefore, in my country's sustainable development strategy, it is urgent to develop a technology that can effectively treat wastes such as oily sludge and realize clean and efficient resource processing 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 uses the physical and chemical properties of supercritical water (temperature>374℃, pressure>22.1MPa) such as high solubility, low dielectric constant, low viscosity and high diffusivity to destroy the emulsified state of oily sludge, directly dissolve the waste organic matter in it, separate the oil and ash, form a homogeneous reaction system, and produce high calorific value hydrogen-rich gas. However, after the oily sludge is heated in supercritical water direct gasification (600℃-700℃), part of the oil easily volatilizes and dissolves in the supercritical water, while the other part of the oil tends to remain inside the particles and may undergo polycondensation to form coke, which will hinder the reaction and become a key limiting factor in the gasification reaction.

[0004] In the supercritical water gasification-oxidation series device for treating oily sludge, the current operating process is to first carry out gasification reaction (600℃-700℃) in the gasification device, and then the material enters the oxidation device for oxidation reaction (900℃-1000℃) and releases a large amount of heat. Since the existing gasification-oxidation series device does not adopt the technical solution of coupling gasification and oxidation, a large amount of heat energy generated in the oxidation stage must be transferred back to the gasification reaction link through the heat exchanger to achieve heat energy reuse. Such a design causes significant heat dissipation loss in the process from gasification to oxidation series, and due to the extremely high temperature released by the oxidation reaction, extremely strict requirements are placed on the heat exchange equipment, which not only reduces the energy efficiency of the entire system, but also increases the demand for high-performance heat exchange devices.

[0005] In the current supercritical water gasification-oxidation coupling device using casing technology, although direct heat transfer is achieved by embedding the gasification reaction device into the oxidation reaction device, so that a large amount of heat energy released during the oxidation process can be directly used for the gasification reaction, this design brings new problems. Since the gasification reaction is slow and the oxidation reaction is violent and releases high heat, it becomes extremely difficult to maintain the thermal balance between the two reactions. This energy mismatch not only leads to low energy utilization efficiency within the system, causing 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 causing safety accidents. In addition, since the gasification reaction is relatively slow and the oxidation reaction is very rapid, excessively high temperatures may also cause the gasification reaction to fail to proceed fully, and some materials will undergo oxidation reaction without being completely gasified, which not only affects the gasification effect, but also the residual reactants pose a safety hazard to the experimental device. Finally, since the pipeline that delivers oxygen to the oxidation reaction only supplies oxygen from a single point, a local violent oxidation reaction is immediately triggered after the oxygen enters, resulting in problems such as uneven heating and incomplete reaction in the reactor.

[0006] At present, the potential value of thermal fluids after supercritical water liquefaction (380℃-450℃), supercritical water gasification (600℃-700℃), and oxidation (900℃-1000℃) of oily sludge has not been fully explored. The thermal energy of such thermal fluids can be effectively used to generate electricity or provide heating to users. 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 model to achieve a win-win situation of economic, environmental and social benefits. Summary of the invention

[0007] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a coupled system and method for supercritical water liquefaction-gasification-oxidation of oily sludge, so as to solve the technical problem of how to improve the cleaning efficiency of sludge in the prior art and thereby achieve rational utilization of resources.

[0008] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a coupled system for supercritical water liquefaction-gasification-oxidation of oily sludge, comprising a liquid oxygen output unit, an oily sludge output unit, a water tank, a slag discharge device, a gas-liquid separation unit, a first heat exchanger, and a coupled reaction device; The coupled reaction device comprises a supercritical water liquefaction reaction device and a supercritical water oxidation reaction device which are sequentially arranged from the outside to the inside; a supercritical water gasification reaction spiral device is arranged in the supercritical water oxidation reaction device; the supercritical water liquefaction reaction device is connected to the supercritical water oxidation reaction device through the supercritical water gasification reaction spiral device; The supercritical water liquefaction reaction device is provided with a water inlet pipe, a feed pipe and a slag discharge pipe; The output end of the oily sludge output unit is connected to the feed pipe, the water tank is provided with two output ends, wherein the first output end is connected to the oily sludge output unit, and the second output end is provided with two branches, wherein one branch is connected to the water inlet pipe after heating; the other branch is connected to the water inlet pipe after passing through the first heat exchanger; the output end of the slag discharge pipe is connected to the slag discharge device; 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-component thermal fluid outlet, and the multi-component thermal fluid outlet 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 heating system is provided between the first heat exchanger and the gas-liquid separation unit, for performing circulating power generation or circulating heating respectively.

[0009] Preferably, the liquid oxygen output unit comprises a liquid oxygen bottle, a liquid oxygen pump and an air preheater; 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, the output end of the air preheater is divided into two groups of branches, and the output ends of the two groups of branches are respectively connected to the input end of the supercritical water oxidation reaction device.

[0010] Further, the input end of the supercritical water oxidation reaction device includes a first air inlet cannula and a second air inlet cannula; The input ends of the first air inlet cannula and the second air inlet cannula are respectively connected to two groups of branches at the output end of the air preheater; the output ends of the first air inlet cannula and the second air inlet cannula are extended into the supercritical water oxidation reaction device, and the first air inlet cannula and the second air inlet cannula are respectively provided with a plurality of air outlet holes on the tube bodies for outputting oxygen in the supercritical water oxidation reaction device.

[0011] Preferably, the supercritical water gasification reaction spiral device includes a gasification spiral tube; wherein the spiral tube inlet of the gasification spiral tube is connected to the supercritical water liquefaction reaction device through the supercritical water oxidation reaction device; and the spiral tube outlet of the gasification spiral tube is arranged in the supercritical water oxidation reaction device.

[0012] Preferably, the oily sludge output unit includes a storage tank, a crusher, a mixer and a material pump; The input end of the storage tank is used to input 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; the output end of the mixer is connected to the feed pipe via a material pump.

[0013] Preferably, a first water pump is provided at the second output end of the water tank, and two branches are provided at the second output end after the first water pump, one of which is provided with a first flow regulating valve and a heating device in sequence, for connecting to the water inlet pipe after heating; and the other branch is provided with a second flow regulating valve, for connecting to the water inlet pipe after passing through the first heat exchanger.

[0014] Preferably, the gas-liquid separation unit comprises a gas-liquid separator, a gas storage bottle, a back pressure valve and a first cooler; 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 bottle, and the liquid output end of the gas-liquid separator is connected to the water tank; The thermal cycle power generation unit or the cycle heating system is respectively arranged between the first heat exchanger and the back pressure valve, and is used for performing cycle power generation or cycle heating respectively.

[0015] Further, when performing cycle power generation, the thermal cycle power generation unit includes a second water pump, a second heat exchanger, a turbine and a second cooler; The second heat exchanger is provided with two groups of input ends and two groups of output ends, wherein 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 turbine, one branch of the output end of the turbine is used to generate electricity to the outside, and the other branch is connected to the input end of the second cooler, and the output end of the second cooler is connected to the other group of input ends of the second heat exchanger after passing through the second water pump, so as to form a heat circulation loop.

[0016] Furthermore, when circulating heating is performed, the circulating heating system includes a second water pump, a second heat exchanger, a heating device and a second cooler; The second heat exchanger is provided with two groups of input ends and two groups of output ends, wherein 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 supplying heat to the outside, and the other branch is connected to the input end of the second cooler, and the output end of the second cooler is connected to the other group of input ends of the second heat exchanger after passing through the second water pump, so as to form a circulating heating loop.

[0017] In a second aspect, the present invention further provides a coupling method for supercritical water liquefaction-gasification-oxidation of oily sludge. Based on the above-mentioned coupling system for supercritical water liquefaction-gasification-oxidation of oily sludge, the coupling method comprises the following steps: Water is put into a water tank, and after being heated through a branch of the water tank, the water is added into a supercritical water liquefaction reaction device through a water inlet pipe to obtain supercritical water; Put the sludge into the oily sludge output unit, add the water in the water tank into the oily sludge output unit, mix them, and then add them into the supercritical water liquefaction reaction device through the feed pipe; Adding liquid oxygen into the liquid oxygen output unit, and inputting the liquid oxygen into the supercritical water oxidation reaction device through the liquid oxygen output unit; The oily sludge and supercritical water are in a supercritical water liquefaction reaction device, wherein a part of the oily sludge is dissolved in the supercritical water, and undergoes a gasification reaction with the supercritical water in a supercritical water gasification reaction spiral device to obtain a gasification product; the other part of the oily sludge residue that is insoluble in the supercritical water sinks to the bottom of the supercritical water liquefaction reaction device by gravity and enters the slag discharge device through the slag discharge pipe; The gasification product and supercritical water enter the supercritical water oxidation reaction device through the supercritical water gasification reaction spiral device to undergo an oxidation reaction to release heat, thereby providing heat for heating 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 to generate a multi-component thermal fluid, which enters the first heat exchanger through the multi-component thermal fluid outlet of the supercritical water oxidation reaction device; Close the heated water flow of one branch in the water tank, and open the other branch of the water tank at the same time, so that the water flow of the other branch enters the first heat exchanger and then is added to the supercritical water liquefaction reaction device through the water inlet pipe to obtain supercritical water, forming a water heat circulation loop; At the same time, the multi-component thermal fluid enters the first heat exchanger and then enters the gas-liquid separation unit, and the separated water enters the water tank for water recycling; When cyclic power generation is performed, the multi-element thermal fluid exchanges heat with the thermal cycle power generation unit to form a thermal cycle loop, which cyclically generates power for the outside world; When circulating heating is performed, the multi-element thermal fluid exchanges heat with the circulating heating system to form a circulating heating loop.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a coupling system of supercritical water liquefaction-gasification-oxidation of oily sludge, which realizes deep treatment of oily sludge by coupling three structures of 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 the thorough removal of residual pollutants. This continuous treatment process greatly improves the efficiency and cleanliness of treatment. The organic components in oily 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 materials, and the oxidation stage ensures the stable operation of the system and the harmless treatment of waste, realizes the conversion from waste to resources, and improves the utilization rate of resources. The present invention adopts supercritical water as the reaction medium, and supercritical water can significantly improve the chemical reaction rate and efficiency under specific 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. Furthermore, after the liquid oxygen is pressurized by a liquid oxygen pump and preheated into gas by an air preheater, it is evenly distributed to the input end of the supercritical water oxidation reactor. This process not only improves the reaction activity and distribution uniformity of oxygen, but also optimizes energy utilization, enhances system stability and safety, while reducing the generation of by-products and improving the overall reaction efficiency.

[0019] Furthermore, the input end of the supercritical water oxidation reaction device includes a first air inlet tube and a second air inlet tube, the walls of which are covered with tiny air outlet holes, ensuring multi-point oxygen supply, allowing oxygen to evenly and fully contact the reactants, greatly promoting the efficiency of the oxidation reaction, and the evenly dispersed oxygen flow also helps to maintain the stability of the reaction temperature, thereby preventing overheating and potential corrosion problems caused by local violent reactions, significantly improving the efficiency of the entire treatment process, while ensuring the safety and reliability of the operation.

[0020] Furthermore, the supercritical water gasification reaction spiral tube device sets the gasification device into a spiral tube shape, and the increase in contact area can ensure uniform heat distribution, enhance the efficiency of absorbing the heat released by the oxidation reaction, maintain thermal balance, and prevent temperature imbalance. If the order of gasification reaction first and then oxidation reaction is carried out, the entire experimental cycle will be lengthened. Placing the supercritical water gasification reaction spiral tube device inside the supercritical water oxidation reaction device can realize the simultaneous gasification reaction and oxidation reaction, shorten the experimental cycle, and optimize the reaction sequence. Due to the use of a long spiral tube design, the gasification reaction path is greatly extended, and the residence time of the oily sludge in the gasification process is increased. This not only ensures that the oily sludge can be completely gasified and prevents coking from clogging the pipeline, but also improves the processing efficiency and flexibility, avoids the problem of insufficient gasification reaction of the oily sludge, and better meets various production needs.

[0021] Furthermore, the oily sludge in the storage tank is first sent to a grinder for fine crushing to grind large particles into fine particles. This process significantly increases the specific surface area of ​​the oily sludge, making the mixing with water in subsequent steps more uniform and thorough. Next, these fine oily sludge particles are fully mixed with water from the water tank in the mixer to form a uniform slurry. By increasing the contact area between the material and the liquid, it not only ensures the complete fusion of the garbage particles and the liquid, but also creates ideal conditions for the supercritical water liquefaction and gasification reaction, improving the reaction efficiency and uniformity. This pretreatment method can not only reduce the energy consumption during the reaction process, but also effectively reduce the risk of pipeline blockage and ensure the stable operation of the system. Finally, through the slurry pump, the prepared slurry can be transported to the supercritical water liquefaction reaction device in a continuous and stable manner, ensuring the smoothness and efficiency of the entire treatment process.

[0022] Furthermore, when the system starts to operate, the water in the water tank first enters the first water pump for pressurization, enters the heating device for heating through the first flow regulating valve, and enters the water inlet pipe. As the reaction proceeds, the water passes through the second flow regulating valve, enters the first heat exchanger, then enters the water inlet pipe, and finally enters the supercritical water liquefaction reaction device, forming a water heat circulation loop to realize hot water circulation, so that heating is no longer required. Therefore, in order to ensure the stability of water volume and pressure, while gradually closing the first flow regulating valve, the second flow regulating valve should be opened gradually accordingly. It is ensured that the degree of closing the first flow regulating valve matches the degree of opening the second flow regulating valve, and the continuity of the water flow and the constancy of the system pressure can be well maintained. It can ensure that there will be no sudden changes in flow or pressure during the conversion process, and a smooth transition can be achieved; therefore, the heating device can be turned off in the subsequent period, and only heat exchange and water are used, which maximizes the utilization of thermal energy and reduces resource waste.

[0023] Furthermore, by introducing a gas-liquid separator, the gas and liquid generated during the treatment process can be separated efficiently; the introduction of a back pressure valve can adjust the pressure in the system, thereby controlling the temperature and pressure of the gas to meet the needs of subsequent treatment steps. The first cooler is not only used to cool the gas, but also releases heat energy during the cooling process. This heat energy can be effectively utilized by the thermal cycle power generation unit or the circulating heating system, thereby further improving the energy efficiency of the system. The setting of the thermal cycle power generation unit enables the system to use the heat energy generated during the treatment process to generate electricity and provide power support for the system or other equipment. This helps to reduce the operating cost of the system and improve the overall economic benefits. The circulating heating system can use heat energy for heating, hot water supply and other purposes to meet the heat energy needs of surrounding areas or enterprises. This multi-purpose energy utilization method further improves the flexibility and practicality of the system.

[0024] Furthermore, as a key device for heat energy conversion, the turbine can convert high-temperature and high-pressure heat energy into mechanical energy, which in turn drives the generator to generate electricity. In this process, the heat energy is efficiently utilized and converted into electrical energy to provide power support for the system or other equipment, reducing the dependence on traditional energy. Through the synergy of the second heat exchanger, the second water pump and the second cooler, a closed heat cycle loop is formed. This loop ensures the continuous flow and effective utilization of heat energy in the system, avoiding the waste of heat energy.

[0025] Furthermore, the circulating heating system can make full use of the heat energy generated during the treatment of oily sludge, transfer it to the heating device through the second heat exchanger, and then provide heat to the outside. This process realizes the efficient use of heat energy and avoids the waste of heat energy. The heating device can adjust the heating power according to actual needs to ensure the stable supply of heat energy and meet the heating needs of surrounding areas or enterprises. Through the synergistic effect of the second water pump, the second heat exchanger and the second cooler, a closed circulating heating loop is formed. This loop ensures the continuous flow and effective use of heat energy in the system, and improves the utilization efficiency of heat energy.

[0026] The present invention also provides a coupling method for supercritical water liquefaction-gasification-oxidation of oily sludge, which utilizes the excellent physical and chemical properties of supercritical water and adopts supercritical water liquefaction, gasification and oxidation technology to achieve efficient and clean transformation of oily sludge, and achieve clean transformation and efficient utilization of materials. In this process, the oxidation reaction releases a large amount of heat energy, which can not only meet the heat demand of the treatment process itself, but also be further converted into electrical energy or other forms of energy, significantly improving resource utilization efficiency and energy recovery rate. The multi-component thermal fluid generated by liquefaction, gasification and oxidation enters the first heat exchanger, can exchange heat with the water in the water tank, and then is introduced into the supercritical water gasification reaction device to complete the water cycle. At the same time, a circulating power generation device is used for heat exchange to achieve energy recovery and use it for power generation, forming a closed-loop energy utilization system. The multi-component thermal fluid after two heat exchanges then flows into the gas-liquid separator, during which the multi-component thermal 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 resources, while the separated liquid is returned to the water tank, realizing the recycling of resources, improving energy utilization and reducing environmental pollution. This integrated design not only improves the overall energy efficiency of the system, but also promotes the effective management of resources and environmental protection, ensuring the sustainability and economic benefits of the entire process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the structure of the coupling system in Example 1 of the present invention; Figure 2 Schematic diagram of the structure of the coupling system in Embodiment 2 of the present invention; In the figure: 1, liquid oxygen bottle; 2, liquid oxygen pump; 3, air preheater; 4, storage tank; 5, crusher; 6, mixer; 7, material pump; 8, water tank; 9, first water pump; 10, heating device; 11, second water pump; 12, water inlet pipe; 13, feed pipe; 14, first air inlet cannula; 15, second air inlet cannula; 16, multi-element thermal 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 tube; 24. Gas-liquid separator; 25. Gas storage cylinder; 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. Heating device. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] The purpose of the present invention is to provide a coupled system and method for supercritical water liquefaction-gasification-oxidation of oily sludge, so as to solve the technical problem of how to improve the cleaning efficiency of sludge in the prior art and thereby realize the rational utilization of resources.

[0031] The present invention is further described in detail below in conjunction with the accompanying drawings: Example 1 See also Figure 1 and Figure 2In this embodiment 1, a coupled system of supercritical water liquefaction-gasification-oxidation of oily sludge is provided, comprising 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 coupled reaction device; the coupled reaction device comprises a supercritical water liquefaction reaction device 21 and a supercritical water oxidation reaction device 22 which are sequentially arranged from the outside to the inside; a supercritical water gasification reaction spiral device 32 is provided in the supercritical water oxidation reaction device 22; the supercritical water liquefaction reaction device 21 is connected to 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, 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, wherein one branch is used for connecting 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-component hot fluid outlet 16, and the multi-component hot fluid outlet 16 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 heating system is provided between the first heat exchanger 26 and the gas-liquid separation unit, for performing circulating power generation or circulating heating respectively.

[0032] Specifically, the liquid oxygen output unit includes 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 end of the supercritical water oxidation reaction device 22.

[0033] In this embodiment, the liquid oxygen bottle 1 is a container for storing liquid oxygen, which can maintain 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 a pipeline. The liquid oxygen pump 2 is the core equipment in the liquid oxygen output unit. Its function is to extract liquid oxygen from the liquid oxygen bottle 1 and pressurize it to the air preheater 3. The main function of the air preheater 3 is to preheat the liquid oxygen entering the supercritical water oxidation reaction device 22.

[0034] Among them, the input end of the supercritical water oxidation reaction device 22 includes a first air inlet tube 14 and a second air inlet tube 15; the input ends of the first air inlet tube 14 and the second air inlet tube 15 are respectively connected to two groups of branches at the output end of the air preheater 3; the output ends of the first air inlet tube 14 and the second air inlet tube 15 are extended into the supercritical water oxidation reaction device 22, and the first air inlet tube 14 and the second air inlet tube 15 are respectively provided with a plurality of air outlet holes on the tube body for outputting oxygen in the supercritical water oxidation reaction device 22.

[0035] In this embodiment, the output ends of the first air inlet cannula 14 and the second air inlet cannula 15 extend into the supercritical water oxidation reaction device 22, and a plurality of air outlets are respectively provided on the tube bodies. The air outlets are used to uniformly output oxygen in the supercritical water oxidation reaction device 22 to ensure that oxygen can be fully mixed with supercritical water and organic matter, thereby performing an efficient oxidation reaction.

[0036] Specifically, the supercritical water gasification reaction spiral device 32 includes a gasification spiral tube 23; wherein the spiral tube inlet 17 of the gasification spiral tube 23 is connected to the supercritical water liquefaction reaction device 21 through the supercritical water oxidation reaction device 22; the spiral tube outlet 18 of the gasification spiral tube 23 is arranged in the supercritical water oxidation reaction device 22.

[0037] In this embodiment, the design of the gasification spiral tube 23 utilizes the unique structure of the spiral tube, which can enhance the flow and heat transfer efficiency of the fluid in the tube. In the spiral tube, due to the centrifugal force generated by the bending of the tube, the fluid at the center of the tube flows to the outside of the tube; at the same time, the fluid close to the outer wall is affected by the pressure gradient and flows inward along the tube walls on both sides. The fluid that merges on the inside of the tube flows toward the outer wall along the horizontal line of the center of the tube cross section, resulting in the formation of two basically symmetrical vortices in the tube. This flow pattern helps to enhance the heat transfer efficiency between the fluid and the tube wall.

[0038] Specifically, the oily sludge output unit includes a storage tank 4, a crusher 5, a mixer 6 and a feed pump 7; the input end of the storage tank 4 is used to input the oily sludge, the output end of the storage tank 4 is connected to the input end of the crusher 5, the output end of the crusher 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 feed pipe 13 via the feed pump 7.

[0039] In this embodiment, the main function of the storage tank 4 is to store the input oily sludge to ensure sufficient sludge supply during the treatment process. The crusher 5 is used to crush the oily sludge output from the storage tank 4 to reduce its particle size for subsequent mixing and transportation. The mixer 6 is used to mix the crushed oily sludge with water from the water tank 8 to form a uniform slurry. The feed pump 7 is used to transport the mixed slurry output from the mixer 6 to the supercritical water liquefaction reaction device 21 through the feed pipe 13.

[0040] Specifically, a first water pump 9 is provided at the second output end of the water tank 8, and two branches are provided at the second output end 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, for connecting to the water inlet pipe 12 after heating; the other branch is provided with a second flow regulating valve 34, for connecting to the water inlet pipe 12 after passing through the first heat exchanger 26.

[0041] In this embodiment, when the system starts to operate, the water in the water tank 8 first enters the first water pump 9 for pressurization, enters the heating device 10 for heating through the first flow regulating valve 33, and enters the water inlet pipe 12. 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 water heat circulation loop to realize hot water circulation, so that heating is no longer required. Therefore, in order to ensure the stability of water volume and pressure, while gradually closing the first flow regulating valve 33, the second flow regulating valve 34 should be opened step by step accordingly. It is ensured that the degree of closing the first flow regulating valve 33 matches the degree of opening the second flow regulating valve 34, and the continuity of the water flow and the constancy of the system pressure can be well maintained. It can ensure that there will be no sudden changes in flow or pressure during the conversion process, and a smooth transition can be achieved; therefore, the heating device 10 can be closed later, and only heat exchange and water are used, so as to maximize the utilization of thermal energy and reduce resource waste.

[0042] Specifically, the gas-liquid separation unit includes a gas-liquid separator 24, a gas storage bottle 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 bottle 25, and the liquid output end of the gas-liquid separator 24 is connected to the water tank 8; the thermal cycle power generation unit or the circulating heating system is respectively arranged between the first heat exchanger 26 and the back pressure valve 28, for respectively performing circulating power generation or circulating heating.

[0043] In this embodiment, by introducing the gas-liquid separator 24, the gas and liquid generated during the treatment process can be efficiently separated; the introduction of the back pressure valve 28 can adjust the pressure in the system, thereby controlling the temperature and pressure of the gas to meet the needs of subsequent treatment steps. The first cooler 29 is not only used to cool the gas, but also releases heat energy during the cooling process. This heat energy can be effectively utilized by the thermal cycle power generation unit or the circulating heating system, thereby further improving the energy utilization efficiency of the system.

[0044] The back pressure valve 28 ensures stable, efficient and safe operation of the fluid system by maintaining minimum operating pressure, preventing backflow, controlling flow and pressure fluctuations, facilitating bubble discharge, assisting reaction conditions and providing safety protection.

[0045] Among them, according to Figure 1 As shown, when cyclic power generation is performed, 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 is provided with two groups of input ends and two groups of output ends, wherein 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 to generate electricity to the outside, 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 after passing through the second water pump 11, so as to form a thermal cycle loop.

[0046] In this embodiment, the turbine 30, as a key device for heat energy conversion, can convert high-temperature and high-pressure heat energy into mechanical energy, thereby driving the generator to generate electricity. In this process, the heat energy is efficiently utilized and converted into electrical energy to provide power support for the system or other equipment, reducing the dependence on traditional energy. Through the synergistic effect of the second heat exchanger 27, the second water pump 11 and the second cooler 31, a closed heat cycle loop is formed. This loop ensures the continuous flow and effective utilization of heat energy in the system, avoiding the waste of heat energy.

[0047] 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; The second heat exchanger 27 is provided with two groups of input ends and two groups of output ends, wherein 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 supplying heat to the outside, 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 after passing through the second water pump 11, so as to form a circulating heating loop.

[0048] In this embodiment, the circulating heating system can make full use of the heat energy generated during the treatment of oily sludge, transfer it to the heating device 35 through the second heat exchanger 27, and then provide heat to the outside. This process realizes the efficient use of heat energy and avoids the waste of heat energy. The heating device 35 can adjust the heating power according to actual needs to ensure a stable supply of heat energy and meet the heating needs of surrounding areas or enterprises. Through the synergistic effect 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 use of heat energy in the system, and improves the utilization efficiency of heat energy.

[0049] In summary, this embodiment provides a coupling system of supercritical water liquefaction-gasification-oxidation of oily sludge, which realizes deep treatment of oily sludge by coupling the three structures of 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 the thorough removal of residual pollutants. This continuous treatment process greatly improves the efficiency and cleanliness of the treatment. The organic components in 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 materials, and the oxidation stage ensures the stable operation of the system and the harmless treatment of waste, realizes the transformation from waste to resources, and improves the utilization rate of resources. The present invention uses supercritical water as a reaction medium, and supercritical water can significantly improve the chemical reaction rate and efficiency under specific 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 use of resources. Example 2 See also 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: Put water into the water tank 8, the water enters the first water pump 9 to be pressurized to more than 22.1MPa, 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 the water is added to the supercritical water liquefaction reaction device 21 to obtain supercritical water; The oily sludge is placed in a storage tank 4, and the storage tank 4 is used to place the oily sludge in a pulverizer 5 for crushing, and then placed in a mixer 6. The water in a water tank 8 is added to the mixer 6 and mixed with the oily sludge, and then enters a feed pump 7, is placed in a feed pipe 13, and is added to a supercritical water liquefaction reaction device 21; The liquid oxygen in the liquid oxygen bottle 1 passes through the liquid oxygen pump 2 and enters the air preheater 3, and the gas then enters the first air inlet cannula 14 and the second air inlet cannula 15, and is added to the supercritical water oxidation reaction device 22 through the air holes of the first air inlet cannula 14 and the second air inlet cannula 15; The oily sludge and supercritical water are in the supercritical water liquefaction reaction device 21, wherein a part of the oily sludge is dissolved in the supercritical water, and undergoes a gasification reaction (600°C-700°C) in the supercritical water gasification reaction spiral device 32 along with the supercritical water to obtain a gasification product; the other part of the oily sludge, which is insoluble in the supercritical water, sinks to 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; The gasification product and supercritical water enter the supercritical water oxidation reaction device 22 through the supercritical water gasification reaction spiral device 32 to undergo an oxidation reaction (900°C-1000°C) to release heat, providing heat for the liquefaction reaction (380°C-450°C) in the supercritical water liquefaction reaction device 21, and at the same time providing heat for the gasification reaction (600°C-700°C) in the supercritical water gasification reaction spiral device 32, generating a multi-component thermal fluid, which enters the first heat exchanger 26 through the multi-component thermal fluid outlet 16 of the supercritical water oxidation reaction device 22; The water in the water tank 8 enters the first water pump 9. In order to ensure the stability of the water volume and pressure, the second flow regulating valve 34 should be opened gradually 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. Doing so can ensure that there will be no sudden changes in flow or pressure during the conversion process, and achieve 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; The multi-component heat fluid enters the first heat exchanger 26 and the second heat exchanger 27, passes through the back pressure valve 28, enters the first cooler 29 for cooling, enters the gas-liquid separator 24, and the separated hydrogen-rich gas enters the gas storage bottle 25, and the separated water enters the water tank 8, realizing water recycling; When circulating power generation is carried out, the multi-component thermal fluid exchanges heat with the thermal cycle power generation unit through the second heat exchanger 27, passes through the turbine 30 and the second cooler 31 in sequence after the heat exchange, reaches the second water pump 11, and then returns to the second heat exchanger 27 for heat exchange, forming a thermal cycle loop to realize circulating power generation.

[0050] When circulating heat is provided, heat is exchanged with the heat cycle power generation unit through the second heat exchanger 27, and after heat exchange, it passes through the heating device 35 and the second cooler 31 in sequence, reaches the second water pump 11, and then returns to the second heat exchanger 27 for heat exchange, forming a circulating heat supply loop.

[0051] In summary, the present embodiment provides a supercritical water liquefaction-gasification-oxidation coupling method for oily sludge, which utilizes the excellent physical and chemical properties of supercritical water, and adopts supercritical water liquefaction, gasification and oxidation technology to achieve efficient and clean transformation of oily sludge, and achieve clean transformation and efficient utilization of materials. In this process, the oxidation reaction releases a large amount of heat energy, which can not only meet the heat demand of the treatment process itself, but also be further converted into electrical energy or other forms of energy, significantly improving resource utilization efficiency and energy recovery rate. The multi-component thermal fluid generated by liquefaction, gasification and oxidation successively enters the first heat exchanger 26 and the second heat exchanger 27, which can exchange heat with the water in the water tank 8, and then is introduced into the supercritical water gasification reaction device to complete the water cycle. At the same time, a circulating power generation device is used for heat exchange to achieve energy recovery and use it for power generation, forming a closed-loop energy utilization system. The multi-component thermal fluid after two heat exchanges then flows into the gas-liquid separator 24, during which the multi-component thermal 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 the recycling of resources, 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 entire process.

[0052] The coupled reaction device couples the supercritical water liquefaction reaction device 21, the supercritical water gasification reaction spiral tube device, and the supercritical water oxidation reaction device 22 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 progress of the experiment. The supercritical water oxidation reaction device 22 releases heat (900℃-1000℃) during oxidation, which is directly transferred to the supercritical water liquefaction reaction (380℃-450℃) device and the supercritical water gasification reaction spiral tube device (600℃-700℃) through wall heat transfer, shortening the time for the reaction to reach the desired temperature, reducing the use of heat exchangers, effectively reducing costs, avoiding heat loss, and realizing energy circulation. At the same time, direct heat transfer technology helps to reduce the energy loss of the system, accelerate the increase in reaction temperature, 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 serious corrosion of the reactor and potential safety accidents caused thereby, and thus ensure the stable and safe operation of the system.

[0053] Supercritical water has adjustable physical and chemical properties. The thermal solvent effect of supercritical water near the critical point (380℃-450℃) is used to efficiently extract the oil phase in the oily sludge and then enter the supercritical water phase to achieve oil-solid separation. The supercritical water liquefaction reaction device 21 uses this property to effectively solve the key problems in the treatment of oily sludge. When the oily sludge is heated in supercritical water, a part of the oil components are easy to volatilize and dissolve in the supercritical water, while the oil that is not easily soluble tends to remain inside the particles and may undergo polycondensation to form coke, which will hinder the reaction. By using supercritical water liquefaction reaction technology (380℃-450℃), effective separation and conversion of oil (saturated hydrocarbons, aromatic hydrocarbons, colloids, asphaltene, etc.) can be achieved: the oil is completely dissolved in supercritical water, and the particles that are insoluble in supercritical water are converted into a form that is easier to handle. The unreacted particulate matter settles to the bottom of the reactor, achieving oil-solid separation. This method not only improves the efficiency and safety of oily sludge treatment, promotes resource recycling, but also prevents coking, insufficient gasification reaction, pipeline blockage and other problems caused by direct gasification reaction of oily sludge. The supercritical water liquefaction reaction device 21 is connected to the slag discharge device 20, which can not only directly collect particulate matter and prevent residue from affecting the experiment, but also improve system stability, extend equipment life, optimize reaction conditions, enhance safety and promote resource recycling, while simplifying the operation process to achieve efficient, safe and environmentally friendly operation.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A coupled system for supercritical water liquefaction-gasification-oxidation of oily sludge, characterized in that: It 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 coupled reaction device; The coupled reaction device comprises a supercritical water liquefaction reaction device (21) and a supercritical water oxidation reaction device (22) which are sequentially arranged from the outside to the inside; a supercritical water gasification reaction spiral device (32) is arranged in the supercritical water oxidation reaction device (22); the supercritical water liquefaction reaction device (21) is connected to the supercritical water oxidation reaction device (22) via 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); 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, wherein one branch is used for heating and then connected to the water inlet pipe (12); 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 thermal fluid outlet (16), and the multi-element thermal fluid outlet (16) is connected to the input end of the gas-liquid separation unit after passing through a first heat exchanger (26), and the liquid output end of the gas-liquid separation unit is connected to a water tank (8); wherein a heat cycle power generation unit or a circulation heating system is provided between the first heat exchanger (26) and the gas-liquid separation unit, for performing circulation power generation or circulation heating respectively.

2. The coupled system of supercritical water liquefaction-gasification-oxidation of oily 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), 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 end of the supercritical water oxidation reaction device (22).

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

4. The coupled system of supercritical water liquefaction-gasification-oxidation of oily sludge according to claim 1, characterized in that: The supercritical water gasification reaction spiral device (32) comprises a gasification spiral tube (23); wherein a spiral tube inlet (17) of the gasification spiral tube (23) is connected to a supercritical water liquefaction reaction device (21) via a supercritical water oxidation reaction device (22); and a spiral tube outlet (18) of the gasification spiral tube (23) is arranged in the supercritical water oxidation reaction device (22).

5. The coupled system of supercritical water liquefaction-gasification-oxidation of oily sludge according to claim 1, characterized in that: The oily sludge output unit comprises a storage tank (4), a crusher (5), a mixer (6) and a material pump (7); The input end of the storage tank (4) is used to input oily 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 feed pipe (13) via the material pump (7).

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

7. The coupled system of supercritical water liquefaction-gasification-oxidation of oily sludge according to claim 1, characterized in that: The gas-liquid separation unit comprises a gas-liquid separator (24), a gas storage bottle (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 bottle (25), and the liquid output end of the gas-liquid separator (24) is connected to the water tank (8); The thermal cycle power generation unit or the circulating heat supply system is respectively arranged between the first heat exchanger (26) and the back pressure valve (28).

8. The coupled system of supercritical water liquefaction-gasification-oxidation of oily sludge according to claim 7, characterized in that: When performing cycle power generation, the thermal 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, wherein 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 to generate electricity to the outside, 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) after passing through the second water pump (11), thereby forming a heat circulation loop.

9. The coupled system of supercritical water liquefaction-gasification-oxidation of oily sludge according to claim 7, characterized in that: When circulating heat supply is performed, the circulating heat supply system comprises a second water pump (11), a second heat exchanger (27), a heating device (35) and a second cooler (31); The second heat exchanger (27) is provided with two groups of input ends and two groups of output ends, wherein 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 to supply heat to the outside, 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) after passing through the second water pump (11), thereby forming a circulating heating loop.

10. A coupled method for supercritical water liquefaction-gasification-oxidation of oily sludge, characterized in that: Based on a coupled system for supercritical water liquefaction-gasification-oxidation of oily sludge according to any one of claims 1 to 9, the coupling method comprises the following steps: Water is placed in a water tank (8), the water is heated through a branch of the water tank (8), and then added to a supercritical water liquefaction reaction device (21) through a water inlet pipe (12) to obtain supercritical water; Putting the sludge into the oily sludge output unit, adding the water in the water tank (8) into the oily sludge output unit, mixing, and then adding the mixed water into the supercritical water liquefaction reaction device (21) through the feed pipe (13); Adding liquid oxygen into a liquid oxygen output unit, and inputting the liquid oxygen into a supercritical water oxidation reaction device (22) through the liquid oxygen output unit; The oily sludge and supercritical water are in a supercritical water liquefaction reaction device (21), wherein a portion of the oily sludge is dissolved in the supercritical water and undergoes a gasification reaction along with the supercritical water in a supercritical water gasification reaction spiral device (32) to obtain a gasification product; the other portion of the oily sludge, which is a residue insoluble in the supercritical water, sinks to the bottom of the supercritical water liquefaction reaction device (21) by gravity and enters the slag discharge device (20) through a slag discharge pipe (19); The gasification product and supercritical water enter the supercritical water oxidation reaction device (22) through the supercritical water gasification reaction spiral device (32) to undergo an oxidation reaction to release heat, thereby providing heat for heating the liquefaction reaction in the supercritical water liquefaction reaction device (21) and simultaneously providing heat for the gasification reaction in the supercritical water gasification reaction spiral device (32), thereby generating a multi-component thermal fluid, which enters the first heat exchanger (26) through the multi-component thermal fluid outlet (16) of the supercritical water oxidation reaction device (22); The water flow of a branch heated in the water tank (8) is closed, and the other branch of the water tank is opened at the same time, so that the water flow of the other branch enters the first heat exchanger (26) and then is added to the supercritical water liquefaction reaction device (21) through the water inlet pipe (12) to obtain supercritical water, thereby forming a water heat circulation loop; At the same time, the multi-component thermal fluid enters the first heat exchanger (26) and then enters the gas-liquid separation unit, and the separated water enters the water tank (8) for water recycling; When cyclic power generation is performed, the multi-element thermal fluid exchanges heat with the thermal cycle power generation unit to form a thermal cycle loop, which cyclically generates power for the outside world; When circulating heating is performed, the multi-element thermal fluid exchanges heat with the circulating heating system to form a circulating heating loop.

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