Coupling type system and method for preparing copper powder through kitchen waste gasification-hydro-thermal synthesis

Abstract

The invention relates to the technical field of waste resource utilization, and discloses a coupling type system and method for preparing copper powder through kitchen waste gasification-hydro-thermal synthesis, and a coupling reaction device in the system comprises a supercritical water gasification module and a supercritical hydro-thermal synthesis module which are sequentially arranged in a sleeving mode from outside to inside; a palladium membrane is arranged between the supercritical water gasification module and the supercritical hydrothermal synthesis module; the outer side wall of the supercritical water gasification module is coated with a heating unit; according to the invention, a supercritical water gasification reactor and a supercritical hydrothermal synthesis reactor are integrated together through a sleeve structure; pure hydrogen is separated from gasification products in the supercritical water gasification module through a palladium membrane, an expensive chemical reducing agent is replaced, effective utilization of kitchen waste slurry is effectively improved, and the utilization rate of conversion from waste to resources is achieved. And meanwhile, pure hydrogen is separated by using a palladium membrane and enters a supercritical hydrothermal synthesis module, so that introduction of impurities is avoided, and preparation of high-purity superfine copper powder can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of waste resource utilization, and in particular to a system and method for preparing copper powder through coupled kitchen waste gasification-hydrothermal synthesis. Background Art

[0002] Ultrafine copper powder, with its unique physical and chemical properties, has shown its indispensable importance in the growing industries such as new energy, electronics and environmental protection. In order to meet the growing demand for high-purity ultrafine copper powder in these industries, researchers have developed a variety of preparation methods, mainly including gas phase method, solid phase method and liquid phase method. However, these methods all have certain limitations.

[0003] Although the gas phase method can produce high-quality copper powder, it has extremely high requirements for equipment, extremely strict reaction conditions, huge energy consumption, and high cost. The solid phase method has difficulties in preparing tiny Cu particles, and it is easy to introduce impurities during the preparation process, thereby affecting the purity of the copper powder. The liquid phase method mainly relies on expensive chemical reducing agents, which undoubtedly increases production costs. Therefore, how to overcome these limitations, improve production efficiency, reduce production costs, and ensure the high purity of copper powder at the same time is a technical problem that needs to be solved in the current field of ultrafine copper powder preparation.

[0004] On the other hand, as an inevitable waste generated in human daily life, food waste is rich in organic matter such as carbohydrates, proteins and lipids, and has the dual attributes of waste and resources. However, the high moisture content (>50 wt%), high oil and high salt content of food waste make it easy to ferment and rot, breed bacteria and flies, and if not handled properly, it will cause serious pollution to the environment. Although food waste contains a large amount of organic matter, it can theoretically be converted into clean energy such as hydrogen through thermochemical methods, but due to its high moisture content, direct combustion is inefficient and requires additional energy for drying pretreatment, which undoubtedly increases the cost and difficulty of treatment.

[0005] In view of the above background, how to organically combine the effective treatment of food waste with the preparation of copper powder to achieve efficient treatment of food waste and prepare high-quality ultrafine copper powder has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a system and method for preparing copper powder by coupled food waste gasification-hydrothermal synthesis, so as to solve the technical problem of how to effectively treat food waste while improving the purity quality of copper powder preparation in the prior art.

[0007] The present invention is achieved through the following technical solutions: In a first aspect, the present invention provides a system for preparing copper powder by coupled gasification-hydrothermal synthesis of food waste, comprising a slurry output pipeline, a first water output pipeline, a copper solution output pipeline, a coupled reaction device, a liquid-solid separation unit, an oxidation reactor, and a multi-directional heat exchanger; The coupled reaction device comprises a supercritical water gasification module and a supercritical hydrothermal synthesis module which are sequentially arranged from the outside to the inside; a palladium membrane is arranged between the supercritical water gasification module and the supercritical hydrothermal synthesis module; and the outer wall of the supercritical water gasification module is coated with a heating unit; The output end of the slurry output pipeline is connected to the input end of the supercritical water gasification module; the first water output pipeline is connected to the input end of the supercritical water gasification module after passing through a multi-directional heat exchanger; The supercritical water gasification module is provided with two groups of output ends, wherein the first group of output ends is used for gasification separation after passing through an oxidation reactor and a multi-directional heat exchanger; the second group of output ends is used for slag discharge treatment; The input end of the copper solution output pipeline is used to input copper solution and alkaline solution; the output end of the copper solution output pipeline is connected to the input end of the supercritical hydrothermal synthesis module, and the output end of the supercritical hydrothermal synthesis module is connected to the liquid-solid separation unit.

[0008] Preferably, the heating unit comprises a plurality of electric heating devices, and the plurality of electric heating devices are wrapped around the outer side wall of the supercritical water gasification module.

[0009] Preferably, a slurry pump is provided on the slurry output pipeline, which is used to pump the kitchen waste slurry through the slurry output pipeline to the input end of the supercritical water gasification module; The first water output pipeline is provided with a first water pump, which is used to pump water through the first water output pipeline to the input end of the supercritical water gasification module.

[0010] Preferably, the copper solution output pipeline includes a copper precursor solution output pipeline and an alkaline solution output pipeline; The input end of the copper precursor solution output pipeline is provided with a copper precursor solution pump for inputting the copper precursor solution; the input end of the alkaline solution output pipeline is provided with an alkaline solution pump for inputting the alkaline solution; The output ends of the copper precursor solution output pipeline and the alkaline solution output pipeline are respectively connected to the input end of the supercritical hydrothermal synthesis module.

[0011] Preferably, the liquid-solid separation unit comprises a first cooler and a liquid-solid separator; The input end of the first cooler is connected to the output end of the supercritical hydrothermal synthesis module, the output end of the first cooler is connected to the input end of the liquid-solid separator, and the output end of the liquid-solid separator is used to separate liquid and copper powder.

[0012] Preferably, the input end of the oxidation reactor is also connected to a liquid oxygen output pipeline, and the liquid oxygen output pipeline is provided with a liquid oxygen pump and an air preheater.

[0013] Preferably, the output end of the multi-directional heat exchanger is connected to a gas-liquid separation unit, and the gas-liquid separation unit includes a second cooler, a gas-liquid separator and a water tank; The input end of the second cooler is connected to the output end of the multi-directional heat exchanger, the output end of the second cooler is connected to the input end of the gas-liquid separator, and the liquid output end of the gas-liquid separator is connected to the water tank.

[0014] Preferably, the second output end of the coupled reaction device is connected to a slag discharge device, and the slag discharge device includes a third cooler and a lock hopper; The input end of the third cooler is connected to the second group of gasification output ends, and the output end of the third cooler is connected to the input end of the lock hopper; the lock hopper is also provided with a water injection pipeline and a slag discharge pipeline; the water injection pipeline is provided with a water injection ball valve, and the slag discharge pipeline is provided with a slag discharge needle valve.

[0015] Preferably, it also includes a second water output pipeline, the output end of which is connected to the input end of the supercritical hydrothermal synthesis module via a multi-directional heat exchanger; a second water pump is provided on the second water output pipeline, which is used to pump water through the second water output pipeline to the input end of the supercritical hydrothermal synthesis module.

[0016] In a second aspect, the present invention further provides a method for using a coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder. Based on the above-mentioned coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder, the method for using the coupled kitchen waste gasification-hydrothermal synthesis system comprises the following steps: The kitchen waste slurry is input into the supercritical water gasification module through the slurry output pipeline, and water is simultaneously heated through the first water output pipeline and then enters the supercritical water gasification module through the multi-directional heat exchanger; The heating unit on the outer wall of the supercritical water gasification module is turned on, so that the water in the supercritical water gasification module and the kitchen waste slurry undergo a gasification reaction to obtain a gasification product, a portion of the gasification product in the supercritical water gasification module is separated by a palladium membrane to obtain pure hydrogen, and the pure hydrogen flows into the supercritical water thermal synthesis module as a reducing agent; The copper solution and the alkaline solution are used as particle modifiers and are input into the supercritical hydrothermal synthesis module through the copper solution output pipeline, and the products are obtained by reduction reaction with the pure hydrogen in the supercritical hydrothermal synthesis module and output to the liquid-solid separation unit for separation to obtain copper powder; The remaining gasification products are outputted through the first output end and the second output end of the supercritical water gasification module respectively, wherein the first output end undergoes oxidation and heat release before gasification and separation to obtain a mixed gas and water, and the second output end undergoes slag removal.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention provides a system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis, in which a supercritical water gasification reactor and a supercritical hydrothermal synthesis reactor are integrated together through a casing structure; the gasification product in the supercritical water gasification module is separated into pure hydrogen through a palladium membrane, and the hydrogen is used as a reducing agent to flow into the supercritical hydrothermal synthesis module, replacing the expensive chemical reducing agent, effectively improving the effective utilization of kitchen waste slurry and realizing the utilization rate of waste to resource conversion. Inter-wall heat transfer reduces system energy loss, accelerates the reaction rate, and improves the energy efficiency of the system. At the same time, the present invention uses a palladium membrane to separate pure hydrogen into a supercritical hydrothermal synthesis module to avoid the introduction of impurities, and can achieve the preparation of high-purity ultrafine copper powder.

[0018] Furthermore, the electric heating device is directly wrapped around the outer wall of the supercritical water gasification module, which can realize direct heating of the supercritical water gasification module, reduce the intermediate links of heat transfer, and thus improve the heating efficiency. Since the electric heating device is evenly distributed on the outer wall of the supercritical water gasification module, it can ensure that the supercritical water gasification module is heated evenly, avoiding local overheating or insufficient heating, and improving the heating efficiency.

[0019] Furthermore, the slurry pump can efficiently pump the food waste slurry from the storage or pretreatment area to the input end of the supercritical water gasification module, reducing the stagnation and loss of the slurry during the transportation process and improving the processing efficiency of the entire system. The first water pump can also ensure that water is pumped to the supercritical water gasification module at a stable pressure and flow rate.

[0020] Furthermore, the copper precursor solution pump and the alkaline solution pump can ensure that their respective solutions are pumped to the supercritical hydrothermal synthesis module at a stable pressure and flow rate; by adjusting the speed or opening degree of the pump, the input flow rate of the copper precursor solution and the alkaline solution can be precisely controlled.

[0021] Furthermore, the first cooler is located at the output end of the supercritical hydrothermal synthesis module to quickly cool the high-temperature and high-pressure fluid output from the synthesis module. The liquid-solid separator receives the cooling fluid from the first cooler and performs liquid-solid separation on it. Since the fluid has been cooled, the liquid and solid components therein are easier to separate.

[0022] Furthermore, the liquid oxygen pump can ensure that the liquid oxygen is delivered to the oxidation reactor at a stable pressure and flow rate. This helps to maintain the oxygen concentration in the oxidation reactor, thereby improving the rate and efficiency of the oxidation reaction. The oxidation reactor is convenient for oxidizing the remaining gasification products, and the oxidation heat release can provide heat for the system, achieving energy self-sufficiency of the system.

[0023] Furthermore, the second cooler is located between the output end of the multidirectional heat exchanger and the gas-liquid separator, and its main function is to cool the fluid output from the multidirectional heat exchanger. It helps to reduce the temperature and pressure of the fluid, making it easier to separate the gas and liquid. The gas-liquid separator receives the cooling fluid from the second cooler and separates the gas and liquid. Since the fluid has been cooled, the gas and liquid components therein are easier to be completely separated.

[0024] Furthermore, the third cooler is located between the second group of output ends of the coupled reaction device and the lock hopper, which cools the solid waste generated after the reaction, helping to quickly cool down the high-temperature solid waste. The lock hopper is used to temporarily store the solid waste cooled by the third cooler. The slag discharge needle valve on the slag discharge pipeline can accurately control the slag discharge flow and speed to ensure the stability and continuity of the slag discharge process. Furthermore, the design of the second water circuit output pipeline allows the water in the system to be recycled. The hot water or wastewater generated in the coupled reaction device or other related equipment is pumped to the supercritical hydrothermal synthesis module through the second water circuit output pipeline as a raw material or heating medium for the synthesis reaction. After the high-temperature water enters the supercritical hydrothermal synthesis module, it can participate in the synthesis reaction more effectively, release more energy, and improve the energy utilization efficiency of the entire system.

[0025] The present invention also provides a method for using a coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder. Kitchen waste is used as a raw material and a gasification reaction is carried out through a supercritical water gasification module, thereby realizing efficient conversion and resource utilization of kitchen waste. Pure hydrogen in the gasification product is used as a reducing agent for preparing copper powder in the supercritical hydrothermal synthesis module, forming a closed loop of resource recycling. Water enters the supercritical water gasification module after being heated through a multi-directional heat exchanger through a first water output pipeline, which not only improves the utilization efficiency of water, but also reduces energy consumption. The application of the palladium membrane separation technology of the present invention can efficiently separate pure hydrogen from the gasification product, ensuring the smooth progress of the subsequent reduction reaction. Copper solution and alkaline solution are used as particle modifiers, and a reduction reaction is carried out through pure hydrogen in the supercritical hydrothermal synthesis module to prepare high-purity copper powder. The liquid-solid separation unit can effectively separate copper powder from the reaction product, thereby improving the purity of the copper powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the principle structure of a system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis in an embodiment of the present invention; In the figure: 1. slurry pump; 2. first water pump; 3. second water pump; 4. copper precursor solution pump; 5. alkaline solution pump; 6. liquid oxygen pump; 7. air preheater; 8. coupled reaction device; 9. supercritical water gasification module; 10. palladium membrane; 11. supercritical hydrothermal synthesis module; 12. electric heating device; 13. first cooler; 14. liquid-solid separator; 15. oxidation reactor; 16. multi-directional heat exchanger; 17. second cooler; 18. gas-liquid separator; 19. water tank; 20. third cooler; 21. lock hopper. DETAILED DESCRIPTION

[0027] 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.

[0028] The purpose of the present invention is to provide a system and method for preparing copper powder by coupled food waste gasification-hydrothermal synthesis, so as to solve the technical problem of how to effectively treat food waste and improve the purity quality of copper powder preparation in the prior art.

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings: Example 1 See also Figure 1 In this embodiment 1, a system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis is provided, comprising a slurry output pipeline, a first water output pipeline, a copper solution output pipeline, a coupled reaction device 8, a liquid-solid separation unit and a multi-directional heat exchanger 16; the coupled reaction device 8 comprises a supercritical water gasification module 9 and a supercritical hydrothermal synthesis module 11 which are sequentially arranged from the outside to the inside; a palladium membrane 10 is provided between the supercritical water gasification module 9 and the supercritical hydrothermal synthesis module 11; the outer wall of the supercritical water gasification module 9 is coated with a heating unit; the output end of the slurry output pipeline is connected to The input end of the supercritical water gasification module 9; the first water circuit output pipeline is connected to the input end of the supercritical water gasification module 9 after passing through the multi-directional heat exchanger 16; the supercritical water gasification module 9 is provided with two groups of output ends, wherein the first group of output ends is used for gasification separation after passing through the oxidation reactor 15 and the multi-directional heat exchanger 16; the second group of output ends is used for slag discharge treatment; the input end of the copper solution output pipeline is used to input copper solution and alkaline solution; the output end of the copper solution output pipeline is connected to the input end of the supercritical hydrothermal synthesis module 11, and the output end of the supercritical hydrothermal synthesis module 11 is connected to the liquid-solid separation unit.

[0030] Specifically, the heating unit includes a plurality of electric heating devices 12 , and the plurality of electric heating devices 12 are wrapped around the outer wall of the supercritical water gasification module 9 .

[0031] In this embodiment, the heat generated by the electric heating device 12 is first transferred to the outer wall of the supercritical water gasification module 9 by heat conduction. The outer wall of the supercritical water gasification module 9 is usually made of a material with good thermal conductivity to ensure that the heat can be quickly and evenly transferred to the inside of the module.

[0032] Specifically, a slurry pump 1 is provided on the slurry output pipeline, which is used to pump the food waste slurry through the slurry output pipeline to the input end of the supercritical water gasification module 9 through the slurry pump 1; the first water circuit output pipeline is provided with a first water pump 2, which is used to pump water through the first water circuit output pipeline to the input end of the supercritical water gasification module 9 through the first water circuit output pipeline.

[0033] In this embodiment, the slurry pump 1 can generate sufficient pressure and flow to ensure that the food waste slurry is stably and efficiently transported to the input end of the supercritical water gasification module 9. By accurately controlling the speed and output pressure of the slurry pump 1, the slurry flow rate can be accurately adjusted to meet the demand for raw materials of the gasification reaction.

[0034] The first water pump 2 can also generate sufficient pressure and flow to pump water into the supercritical water gasification module 9 through the first water output pipeline.

[0035] The stable delivery of water is essential to maintaining the temperature and pressure conditions in the gasification module, and the first water pump 2 ensures the smooth progress of this process.

[0036] Specifically, the copper solution output pipeline includes a copper precursor solution output pipeline and an alkaline solution output pipeline; The input end of the copper precursor solution output pipeline is provided with a copper precursor solution pump 4 for inputting the copper precursor solution; the input end of the alkaline solution output pipeline is provided with an alkaline solution pump 5 for inputting the alkaline solution; the output ends of the copper precursor solution output pipeline and the alkaline solution output pipeline are respectively connected to the input end of the supercritical hydrothermal synthesis module 11.

[0037] In this embodiment, the copper precursor solution pump 4 and the alkaline solution pump 5 control the input of the copper precursor solution and the alkaline solution respectively, realizing independent control of the two raw materials. This independence enables the system to accurately adjust the input amount of each raw material as needed, thereby optimizing the reaction conditions and improving the product quality.

[0038] When the copper precursor solution and the alkaline solution are mixed in the supercritical hydrothermal synthesis module 11, since the flow rates of the two raw materials are precisely controlled, uniform mixing can be achieved more easily.

[0039] Specifically, the liquid-solid separation unit includes a first cooler 13 and a liquid-solid separator 14; The input end of the first cooler 13 is connected to the output end of the supercritical hydrothermal synthesis module 11, and the output end of the first cooler 13 is connected to the input end of the liquid-solid separator 14. The output end of the liquid-solid separator 14 is used to separate liquid and copper powder.

[0040] In this embodiment, the input end of the first cooler 13 is connected to the output end of the supercritical hydrothermal synthesis module 11 to receive the high-temperature and high-pressure fluid coming out of the supercritical hydrothermal synthesis module 11 .

[0041] The first cooler 13 transfers heat from the high-temperature fluid to the cooling medium through the heat exchange principle, thereby reducing the temperature of the fluid.

[0042] The input end of the liquid-solid separator 14 receives the cooled fluid from the first cooler 13. The copper powder in the fluid is separated from the liquid by using liquid-solid separation techniques such as gravity sedimentation, filtration, centrifugal separation, etc.

[0043] Specifically, the input end of the oxidation reactor 15 is also connected to a liquid oxygen output pipeline, and the liquid oxygen output pipeline is provided with a liquid oxygen pump 6 and an air preheater 7.

[0044] Among them, the output end of the multi-directional heat exchanger 16 is connected to the gas-liquid separation unit, and the gas-liquid separation unit includes a second cooler 17, a gas-liquid separator 18 and a water tank 19; the input end of the second cooler 17 is connected to the output end of the multi-directional heat exchanger 16, the output end of the second cooler 17 is connected to the input end of the gas-liquid separator 18, the liquid output end of the gas-liquid separator 18 is connected to the water tank 19, and a back pressure valve is provided between the second cooler 17 and the gas-liquid separator 18 for maintaining the system pressure.

[0045] In this embodiment, the liquid oxygen pump 6 is used to extract liquid oxygen from the storage tank and pressurize it so as to transport it to the air preheater 7 and the oxidation reactor 15.

[0046] The air preheater 7 preheats the liquid oxygen to increase its temperature when it enters the oxidation reactor 15, thereby enhancing the efficiency of the oxidation reaction.

[0047] In the oxidation reactor 15, the preheated liquid oxygen is mixed with the fluid from the supercritical water gasification module 9, and an oxidation reaction occurs under high temperature conditions.

[0048] Specifically, the second output end of the coupling reaction device 8 is connected to a slag discharge device, and the slag discharge device includes a third cooler 20 and a lock hopper 21; The input end of the third cooler 20 is connected to the second group of gasification output ends, and the output end of the third cooler 20 is connected to the input end of the lock hopper 21; the lock hopper 21 is also provided with a water injection pipeline and a slag discharge pipeline; the water injection pipeline is provided with a water injection ball valve, and the slag discharge pipeline is provided with a slag discharge needle valve.

[0049] Specifically, the system also includes a second water output pipeline, the output end of which is connected to the input end of the supercritical hydrothermal synthesis module 11 via a multi-directional heat exchanger 16; a second water pump 3 is provided on the second water output pipeline, which is used to pump water through the second water output pipeline to the input end of the supercritical hydrothermal synthesis module 11 through the second water pump 3.

[0050] In summary, the present invention provides a coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder, in which a supercritical water gasification reactor and a supercritical hydrothermal synthesis reactor are integrated together through a sleeve structure; the gasification product in the supercritical water gasification module 9 is separated into pure hydrogen through a palladium membrane 10, and the hydrogen flows into the supercritical hydrothermal synthesis module 11 as a reducing agent, replacing the expensive chemical reducing agent, effectively improving the effective utilization of the kitchen waste slurry, and realizing the utilization rate of waste to resource conversion. Inter-wall heat transfer reduces system energy loss, accelerates the reaction rate, and improves the energy efficiency of the system. At the same time, the present invention uses a palladium membrane 10 to separate pure hydrogen into the supercritical hydrothermal synthesis module 11, avoiding the introduction of impurities, and can achieve the preparation of high-purity ultrafine copper powder.

[0051] Example 2 In this embodiment 2, a method for using a coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder is provided. Based on the above-mentioned coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder, the method for using the coupled kitchen waste gasification-hydrothermal synthesis system comprises the following steps: The kitchen waste slurry is driven by the slurry pump 1 at a pressure of 23-30 MPa, and is input into the supercritical water gasification module 9 through the slurry output pipeline. At the same time, water is driven by the first water pump 2 at a pressure of 23-30 MPa, and is heated through the first water output pipeline through the multi-directional heat exchanger 16 and then enters the supercritical water gasification module 9; The electric heating device 12 on the outer wall of the supercritical water gasification module 9 is turned on for the system startup process, and is turned off after the system runs smoothly. The water in the supercritical water gasification module 9 and the kitchen waste slurry undergo a gasification reaction to obtain a gasification product. A portion of the gasification product in the supercritical water gasification module 9 is separated by the palladium membrane 10 to obtain pure hydrogen. The pure hydrogen flows into the supercritical hydrothermal synthesis module 11 as a reducing agent. At this time, the temperature in the supercritical hydrothermal synthesis module 11 is less than 450°C. The liquid oxygen is pressurized at a pressure of 23-30 MPa by the liquid oxygen pump 6, heated to 25° C. by the air preheater 7, and then enters the oxidation reactor 15 to react with the remaining gasification products.

[0052] The copper precursor solution pump 4 inputs the copper precursor solution (CuSO4, Cu(NO3)2, Cu(HCOO)2 and other precursors) and alkaline solution (modifiers such as NaOH and KOH) as particle modifiers into the supercritical hydrothermal synthesis module 11 under a pressure of 23-30 MPa, and the water flows through the second water output pipeline of the second water pump 3 at a pressure of 23-30 MPa, and then flows into the supercritical hydrothermal synthesis module 11 after being preheated by the multi-directional heat exchanger 16. The copper solution and the alkaline solution are used as particle modifiers, and the products are obtained by reduction reaction with the pure hydrogen in the supercritical hydrothermal synthesis module 11, and are cooled to 25°C by the first cooler 13, and high-purity ultrafine copper powder can be separated in the liquid-solid separator 14.

[0053] The remaining gasification products in the supercritical water gasification module 9 are separated into ash online, and the separated slag particles are transported to the third cooler 20 and cooled to 25°C before entering the lock hopper 21. When the lock hopper 21 is discharged, the water injection ball valve is opened, and water is injected into the lock hopper 21 to a certain pressure, and then the ball valve is closed. Then the slag discharge needle valve is quickly opened. When the pressure of the entire system reaches equilibrium, the slag discharge needle valve will be closed. At this time, the lock hopper 21 is completely isolated from the supercritical water gasification module 9. Then the ball valve is opened, and the liquid-solid mixture in the lock hopper 21 is discharged.

[0054] At the same time, the gas-liquid products after ash separation enter the oxidation reactor 15 for oxidation, and the temperature in the oxidation reactor 15 is 800-1000° C. The oxidation products enter the multi-directional heat exchanger 16 to provide heat for preheating water, and then release heat in the second cooler 17. The cooled mixed product is separated into mixed gas and water by the gas-liquid separator 18.

[0055] In summary, the method for using a coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder provided in this embodiment uses kitchen waste as raw material, and performs gasification reaction through supercritical water gasification module 9, thereby realizing efficient conversion and resource utilization of kitchen waste. Pure hydrogen in the gasification product is used as a reducing agent for preparing copper powder in supercritical hydrothermal synthesis module 11, forming a closed loop of resource recycling. Water enters supercritical water gasification module 9 after being heated through multi-directional heat exchanger 16 through the first water output pipeline, which not only improves the utilization efficiency of water, but also reduces energy consumption. The application of the separation technology of palladium membrane 10 of the present invention can efficiently separate pure hydrogen from the gasification product, ensuring the smooth progress of the subsequent reduction reaction. Copper solution and alkaline solution are used as particle modifiers, and pure hydrogen in supercritical hydrothermal synthesis module 11 is used for reduction reaction to prepare high-purity copper powder. The liquid-solid separation unit can effectively separate copper powder from the reaction product, thereby improving the purity of copper powder.

[0056] In the present invention, the coupling reaction device 8 integrates the supercritical water gasification reactor and the supercritical hydrothermal synthesis reactor through a sleeve structure; the supercritical hydrothermal synthesis module 11 is in the inner layer, and the supercritical water gasification module 9 is in the outer layer; and an electric heating device 12 is arranged at the outermost layer of the coupling reaction device 8, which is used in the system startup process and is turned off after the system runs stably. The supercritical water gasification module 9 of the reaction device is connected to the supercritical hydrothermal synthesis module 11 through a palladium membrane 10, so that the pure hydrogen in the hydrogen-rich synthesis gas generated by the supercritical water gasification of the kitchen waste is separated and enters the supercritical hydrothermal synthesis module 11, and the pure hydrogen directly replaces the reducing agent to reduce the high-purity ultrafine copper powder.

[0057] The supercritical water gasification module 9 of the coupling device in the present invention directly transfers heat to the supercritical water thermal synthesis module 11, reducing the use of heat exchangers and reducing costs. Direct heat transfer can also reduce system energy loss and improve the energy efficiency of the system. This system converts low-grade garbage into high-grade hydrogen, making the hydrogen conversion efficiency reach 92%, realizing the conversion of waste into resources.

[0058] 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 system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis, characterized in that: It comprises a slurry output pipeline, a first water output pipeline, a copper solution output pipeline, a coupled reaction device (8), a liquid-solid separation unit, an oxidation reactor (15), and a multi-directional heat exchanger (16); The coupled reaction device (8) comprises a supercritical water gasification module (9) and a supercritical hydrothermal synthesis module (11) which are sequentially arranged from the outside to the inside; a palladium membrane (10) is provided between the supercritical water gasification module (9) and the supercritical hydrothermal synthesis module (11); and the outer wall of the supercritical water gasification module (9) is coated with a heating unit; The output end of the slurry output pipeline is connected to the input end of the supercritical water gasification module (9); the first water output pipeline is connected to the input end of the supercritical water gasification module (9) after passing through a multi-directional heat exchanger (16); The supercritical water gasification module (9) is provided with two groups of output ends, wherein the first group of output ends is used for gasification separation after passing through the oxidation reactor (15) and the multi-directional heat exchanger (16); and the second group of output ends is used for slag discharge processing; The input end of the copper solution output pipeline is used to input the copper solution and the alkaline solution; the output end of the copper solution output pipeline is connected to the input end of the supercritical hydrothermal synthesis module (11), and the output end of the supercritical hydrothermal synthesis module (11) is connected to the liquid-solid separation unit.

2. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: The heating unit comprises a plurality of electric heating devices (12), and the plurality of electric heating devices (12) are wrapped and arranged on the outer side wall of the supercritical water gasification module (9).

3. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: The slurry output pipeline is provided with a slurry pump (1), which is used to pump the kitchen waste slurry through the slurry output pipeline to the input end of the supercritical water gasification module (9) through the slurry pump (1); The first water circuit output pipeline is provided with a first water pump (2), which is used to pump water through the first water circuit output pipeline to the input end of the supercritical water gasification module (9) through the first water pump (2).

4. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: The copper solution output pipeline includes a copper precursor solution output pipeline and an alkaline solution output pipeline; The input end of the copper precursor solution output pipeline is provided with a copper precursor solution pump (4) for inputting the copper precursor solution; An alkaline solution pump (5) is provided at the input end of the alkaline solution output pipeline for inputting the alkaline solution; The output ends of the copper precursor solution output pipeline and the alkaline solution output pipeline are respectively connected to the input end of the supercritical hydrothermal synthesis module (11).

5. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: The liquid-solid separation unit comprises a first cooler (13) and a liquid-solid separator (14); The input end of the first cooler (13) is connected to the output end of the supercritical hydrothermal synthesis module (11), the output end of the first cooler (13) is connected to the input end of the liquid-solid separator (14), and the output end of the liquid-solid separator (14) is used to separate liquid and copper powder.

6. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: The input end of the oxidation reactor (15) is also connected to a liquid oxygen output pipeline, and the liquid oxygen output pipeline is provided with a liquid oxygen pump (6) and an air preheater (7).

7. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: The output end of the multidirectional heat exchanger (16) is connected to a gas-liquid separation unit, and the gas-liquid separation unit comprises a second cooler (17), a gas-liquid separator (18) and a water tank (19); The input end of the second cooler (17) is connected to the output end of the multi-directional heat exchanger (16), the output end of the second cooler (17) is connected to the input end of the gas-liquid separator (18), and the liquid output end of the gas-liquid separator (18) is connected to the water tank (19).

8. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: The second output end of the coupled reaction device (8) is connected to a slag discharge device, and the slag discharge device comprises a third cooler (20) and a lock hopper (21); The input end of the third cooler (20) is connected to the second group of gasification output ends, and the output end of the third cooler (20) is connected to the input end of the lock hopper (21); the lock hopper (21) is also provided with a water injection pipeline and a slag discharge pipeline; the water injection pipeline is provided with a water injection ball valve, and the slag discharge pipeline is provided with a slag discharge needle valve.

9. The system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to claim 1, characterized in that: It also comprises a second water output pipeline, the output end of the second water output pipeline being connected to the input end of the supercritical hydrothermal synthesis module (11) via a multi-directional heat exchanger (16); a second water pump (3) is provided on the second water output pipeline, which is used to pump water through the second water output pipeline to the input end of the supercritical hydrothermal synthesis module (11) via the second water pump (3).

10. A method for using a coupled kitchen waste gasification-hydrothermal synthesis system for preparing copper powder, characterized in that: A system for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis according to any one of claims 1 to 9, wherein the method of using the system comprises the following steps: The kitchen waste slurry is input into the supercritical water gasification module (9) through the slurry output pipeline, and water is simultaneously input into the supercritical water gasification module (9) after being heated by the multi-directional heat exchanger (16) through the first water output pipeline; The heating unit on the outer wall of the supercritical water gasification module (9) is turned on, so that the water in the supercritical water gasification module (9) and the food waste slurry undergo a gasification reaction to obtain a gasification product, a portion of the gasification product in the supercritical water gasification module (9) is separated by a palladium membrane (10) to obtain pure hydrogen, and the pure hydrogen flows into the supercritical water thermal synthesis module (11) as a reducing agent; The copper solution and the alkaline solution are used as particle modifiers and are input into the supercritical hydrothermal synthesis module (11) through the copper solution output pipeline, and a reduction reaction is carried out with the pure hydrogen in the supercritical hydrothermal synthesis module (11) to obtain a product, which is then output to the liquid-solid separation unit for separation to obtain copper powder; The remaining gasification products are outputted through the first output end and the second output end of the supercritical water gasification module (9) respectively, wherein the first output end is oxidized and released heat before gasification and separation to obtain a mixed gas and water, and the second output end is used for slag removal.

Images