System and method for preparing copper powder by coupled kitchen waste gasification-hydrothermal synthesis

Abstract

The present invention relates to the technical field of waste resource utilization, and discloses a system and method for preparing copper powder by coupled gasification-hydrothermal synthesis of kitchen waste, wherein a coupled reaction device comprises a supercritical water gasification module and a supercritical hydrothermal synthesis module which are sequentially arranged from outside to inside; a palladium membrane is arranged between the supercritical water gasification module and the supercritical hydrothermal synthesis module; the outer wall of the supercritical water gasification module is coated with a heating unit; the present invention integrates the supercritical water gasification reactor and the supercritical hydrothermal synthesis reactor together through a sleeve structure; the gasification product in the supercritical water gasification module is separated into pure hydrogen through a palladium membrane, which replaces an expensive chemical reducing agent, effectively improves the effective utilization of kitchen waste slurry, and realizes the utilization rate of waste to resource conversion. At the same time, pure hydrogen is separated by a palladium membrane to enter the supercritical hydrothermal synthesis module to avoid the introduction of impurities, so that the preparation of high-purity ultrafine copper powder can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste resource utilization, and specifically to a system and method for coupling gasification and hydrothermal synthesis of kitchen waste to prepare copper powder. Background Art

[0002] Ultra-fine copper powder, with its unique physical and chemical properties, has shown indispensable importance in the increasingly developing industries such as new energy, electronics, and environmental protection. To meet the growing demand for high-purity ultra-fine copper powder in these industries, researchers have developed various 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 prepare high-quality copper powder, it has extremely high requirements for equipment, extremely strict reaction conditions, huge energy consumption, and high costs. The solid-phase method has difficulties in preparing tiny Cu particles and is prone to introducing impurities during the preparation process, thus affecting the purity of the copper powder. The liquid-phase method mainly relies on expensive chemical reducing agents, which undoubtedly increases the production cost. Therefore, how to overcome these limitations, improve production efficiency, reduce production costs, and at the same time ensure the high purity of the copper powder is an urgent technical problem to be solved in the current field of ultra-fine copper powder preparation.

[0004] On the other hand, kitchen waste, as an inevitable waste generated in human daily life, is rich in organic substances 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 characteristics of kitchen waste make it easy to ferment and deteriorate, breed bacteria and flies. If not properly treated, it will cause serious environmental pollution. Although kitchen waste contains a large amount of organic substances, theoretically it can be converted into clean energy such as hydrogen through thermochemical methods. However, due to its high moisture content, the direct combustion efficiency is low, and additional energy is required for drying pretreatment, which undoubtedly increases the treatment cost and difficulty.

[0005] In view of the above background, how to organically combine the effective treatment of kitchen waste with copper powder preparation to achieve the efficient treatment of kitchen waste while preparing high-quality ultra-fine copper powder has become an urgent technical problem to be solved. Summary of the Invention

[0006] In order to overcome the defects of the above-mentioned existing technologies, the purpose of the present invention is to provide a system and method for coupling gasification and hydrothermal synthesis of kitchen waste to prepare copper powder, so as to solve the technical problem of how to effectively treat kitchen waste while improving the purity and quality of copper powder preparation in the existing technology.

[0007] The present invention is realized through the following technical solutions:

[0008] In a first aspect, the present invention provides a system for coupling the gasification of kitchen waste and hydrothermal synthesis to prepare copper powder, which includes a slurry output pipeline, a first water output pipeline, a copper solution output pipeline, a coupling reaction device, a liquid-solid separation unit, an oxidation reactor, and a multi-way heat exchanger;

[0009] The coupling reaction device includes a supercritical water gasification module and a supercritical hydrothermal synthesis module which are sequentially sleeved from the outside to the inside; a palladium membrane is provided between the supercritical water gasification module and the supercritical hydrothermal synthesis module; a heating unit is coated on the outer side wall of the supercritical water gasification module;

[0010] 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 the multi-way heat exchanger;

[0011] 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 the oxidation reactor and the multi-way heat exchanger; the second group of output ends is used for slag discharge treatment;

[0012] The input end of the copper solution output pipeline is used for inputting 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.

[0013] Preferably, the heating unit includes a plurality of electric heating devices, and the plurality of electric heating devices are wrapped on the outer side wall of the supercritical water gasification module.

[0014] Preferably, a slurry pump is provided on the slurry output pipeline, and the slurry pump is used to pump the kitchen waste slurry into the input end of the supercritical water gasification module through the slurry output pipeline;

[0015] A first water pump is provided on the first water output pipeline, and the first water pump is used to pump water into the input end of the supercritical water gasification module through the first water output pipeline.

[0016] Preferably, the copper solution output pipeline includes a copper precursor solution output pipeline and an alkaline solution output pipeline;

[0017] A copper precursor solution pump is provided at the input end of the copper precursor solution output pipeline for inputting copper precursor solution; an alkaline solution pump is provided at the input end of the alkaline solution output pipeline for inputting alkaline solution;

[0018] 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.

[0019] Preferably, the liquid-solid separation unit includes a first cooler and a liquid-solid separator;

[0020] The input end of the first cooler is connected to the output end of the supercritical hydrothermal synthesis module, and the output end of the first cooler is connected to the input end of the liquid-solid separator. The output end of the liquid-solid separator is used to separate and obtain liquid and copper powder.

[0021] Preferably, a liquid oxygen output pipeline is further connected to the input end of the oxidation reactor, and a liquid oxygen pump and an air preheater are provided on the liquid oxygen output pipeline.

[0022] Preferably, the output end of the multi-way 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;

[0023] The input end of the second cooler is connected to the output end of the multi-way 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.

[0024] Preferably, a slag discharging device is connected to the second group of output ends of the coupling reaction device, and the slag discharging device includes a third cooler and a lock hopper;

[0025] 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; a water injection pipeline and a slag discharging pipeline are further provided on the lock hopper; a water injection ball valve is provided on the water injection pipeline, and a slag discharging needle valve is provided on the slag discharging pipeline.

[0026] Preferably, a second water output pipeline is further included, and the output end of the second water output pipeline is connected to the input end of the supercritical hydrothermal synthesis module through a multi-way heat exchanger; a second water pump is provided on the second water output pipeline for pumping water into the input end of the supercritical hydrothermal synthesis module through the second water output pipeline by means of the second water pump.

[0027] In a second aspect, the present invention further provides a use method of a system for coupling kitchen waste gasification-hydrothermal synthesis to prepare copper powder. Based on the above-mentioned system for coupling kitchen waste gasification-hydrothermal synthesis to prepare copper powder, the use method includes the following steps:

[0028] Input the kitchen waste slurry into the supercritical water gasification module through the slurry output pipeline, and at the same time, water enters the supercritical water gasification module after being heated through the multi-way heat exchanger through the first water output pipeline;

[0029] Open the heating unit on the outer wall of the supercritical water gasification module, so that the water in the supercritical water gasification module and the kitchen waste slurry carry out a gasification reaction to obtain a gasification product. A part of the gasification product in the supercritical water gasification module is separated through a palladium membrane to obtain pure hydrogen, and the pure hydrogen flows into the supercritical hydrothermal synthesis module as a reducing agent;

[0030] The copper solution and the alkaline solution are input into the supercritical hydrothermal synthesis module as particle modifiers through the copper solution output pipeline, and react with pure hydrogen in the supercritical hydrothermal synthesis module to obtain a product, which is then output to the liquid-solid separation unit to separate copper powder.

[0031] The remaining gasification products are respectively output through the first group of output terminals and the second group of output terminals of the supercritical water gasification module. Among them, through the first group of output terminals, after oxidation and exothermic reaction, gasification separation is carried out to obtain a mixed gas and water, and slag discharge treatment is carried out through the second group of output terminals.

[0032] Compared with the prior art, the present invention has the following beneficial technical effects:

[0033] The present invention provides a system for coupling the gasification of kitchen waste and hydrothermal synthesis to prepare copper powder, integrating a supercritical water gasification reactor and a supercritical hydrothermal synthesis reactor through a sleeve structure; the gasification products in the supercritical water gasification module are separated into pure hydrogen through a palladium membrane, and the hydrogen flows into the supercritical hydrothermal synthesis module as a reducing agent, replacing expensive chemical reducing agents, effectively improving the effective utilization of kitchen waste slurry and realizing the utilization rate of converting waste into resources. Heat transfer between walls 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 the supercritical hydrothermal synthesis module, avoiding the introduction of impurities, and can realize the preparation of high-purity ultrafine copper powder.

[0034] Furthermore, the electric heating device is directly wrapped on the outer wall of the supercritical water gasification module, which can directly heat the supercritical water gasification module, reducing the intermediate link of heat transfer, thereby improving 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.

[0035] Furthermore, the slurry pump can efficiently pump the kitchen 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 transportation, 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.

[0036] 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 pump speed or opening degree, the input flow rates of the copper precursor solution and the alkaline solution can be precisely controlled.

[0037] Furthermore, the first cooler is located at the output end of the supercritical hydrothermal synthesis module to rapidly cool the high-temperature and high-pressure fluid output from the synthesis module. The liquid-solid separator receives the cooled fluid from the first cooler and performs liquid-solid separation on it. Since the fluid has been cooled, the liquid and solid components in it are easier to separate.

[0038] Furthermore, the liquid oxygen pump can ensure that 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 increasing the rate and efficiency of the oxidation reaction. The oxidation reactor facilitates the oxidation of the remaining gasified products, and the exothermic oxidation can provide heat for the system to achieve energy self-sufficiency of the system.

[0039] Furthermore, the second cooler is located between the output end of the multi-pass heat exchanger and the gas-liquid separator. Its main function is to cool the fluid output from the multi-pass heat exchanger. This helps to reduce the temperature and pressure of the fluid, making it easier to perform gas-liquid separation. The gas-liquid separator receives the cooled fluid from the second cooler and performs gas-liquid separation on it. Since the fluid has been cooled, the gas and liquid components in it are easier to be completely separated.

[0040] Furthermore, the third cooler is located between the second group output end of the coupling reaction device and the lock hopper to cool the solid waste generated after the reaction, which helps to rapidly 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 precisely control the slag discharge flow rate and speed to ensure the stability and continuity of the slag discharge process.

[0041] Furthermore, the design of the second water output pipeline enables the water in the system to be recycled. The hot water or wastewater generated in the coupling reaction device or other related equipment is pumped to the supercritical hydrothermal synthesis module through the second water output pipeline to serve as the raw material or heating medium for the synthesis reaction. After the high-temperature water enters the supercritical hydrothermal synthesis module, it can more effectively participate in the synthesis reaction, release more energy, and improve the energy utilization efficiency of the entire system.

[0042] The present invention also provides a method for using a system for coupling kitchen waste gasification - hydrothermal synthesis to prepare copper powder. Using kitchen waste as raw material, gasification reaction is carried out through a supercritical water gasification module, realizing the efficient conversion and resource utilization of kitchen waste. The pure hydrogen in the gasification products is used as a reducing agent for the preparation of 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 by a multi - way heat exchanger through the first water output pipeline, which not only improves the water utilization efficiency 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 products, ensuring the smooth progress of the subsequent reduction reaction. Copper solution and alkaline solution are used as particle modifiers, and reduction reaction is carried out by the pure hydrogen in the supercritical hydrothermal synthesis module to prepare high - purity copper powder. The liquid - solid separation unit can effectively separate the copper powder from the reaction products, improving the purity of the copper powder. Brief Description of the Drawings

[0043] Figure 1 It is a schematic diagram of the principle structure of the system for coupling kitchen waste gasification - hydrothermal synthesis to prepare copper powder in the embodiment of the present invention;

[0044] 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, coupling 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 - way heat exchanger; 17, second cooler; 18, gas - liquid separator; 19, water tank; 20, third cooler; 21, lock hopper. Detailed Embodiments

[0045] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0046] The purpose of the present invention is to provide a system and method for coupling kitchen waste gasification - hydrothermal synthesis to prepare copper powder, so as to solve the technical problem of how to effectively treat kitchen waste and improve the purity and quality of copper powder preparation in the prior art.

[0047] The following further describes the present invention in detail with reference to the accompanying drawings:

[0048] Example 1

[0049] See Figure 1 In this Embodiment 1, a system for coupling kitchen waste gasification and hydrothermal synthesis to prepare copper powder is provided, which includes a slurry output pipeline, a first water output pipeline, a copper solution output pipeline, a coupling reaction device 8, a liquid-solid separation unit, and a multi-way heat exchanger 16; the coupling reaction device 8 includes a supercritical water gasification module 9 and a supercritical hydrothermal synthesis module 11 which are sleeved from the outside to the inside in sequence; a palladium membrane 10 is arranged between the supercritical water gasification module 9 and the supercritical hydrothermal synthesis module 11; a heating unit is coated on the outer side wall of the supercritical water gasification module 9; 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 the multi-way 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-way 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 for inputting 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.

[0050] Specifically, the heating unit includes 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.

[0051] In this embodiment, the heat generated by the electric heating device 12 is first transferred to the outer side wall of the supercritical water gasification module 9 by means of heat conduction. The outer side 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.

[0052] Specifically, a slurry pump 1 is arranged on the slurry output pipeline, and is used to pump the kitchen waste slurry into the input end of the supercritical water gasification module 9 through the slurry output pipeline by means of the slurry pump 1; a first water pump 2 is arranged on the first water output pipeline, and is used to pump water into the input end of the supercritical water gasification module 9 through the first water output pipeline by means of the first water pump 2.

[0053] In this embodiment, the slurry pump 1 can generate sufficient pressure and flow rate to ensure that the kitchen waste slurry is stably and efficiently transported to the input end of the supercritical water gasification module 9. By precisely controlling the rotation speed and output pressure of the slurry pump 1, the precise adjustment of the slurry flow rate can be realized, so as to meet the requirements of the gasification reaction for raw materials.

[0054] The first water pump 2 can also generate sufficient pressure and flow rate to pump water into the supercritical water gasification module 9 through the first water output pipeline.

[0055] The stable delivery of water is crucial for maintaining the temperature and pressure conditions within the gasification module, and the first water pump 2 ensures the smooth progress of this process.

[0056] Specifically, the copper solution output pipeline includes a copper precursor solution output pipeline and an alkaline solution output pipeline;

[0057] 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.

[0058] In this embodiment, the copper precursor solution pump 4 and the alkaline solution pump 5 respectively control the input of the copper precursor solution and the alkaline solution, achieving independent control of the two raw materials. This independence enables the system to precisely adjust the input amount of each raw material according to needs, thereby optimizing the reaction conditions and improving the product quality.

[0059] When the copper precursor solution and the alkaline solution are mixed within the supercritical hydrothermal synthesis module 11, due to the precise control of the flow rates of the two raw materials, uniform mixing can be more easily achieved.

[0060] Specifically, the liquid-solid separation unit includes a first cooler 13 and a liquid-solid separator 14;

[0061] 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 and obtain liquid and copper powder.

[0062] In this embodiment, the input end of the first cooler 13 is connected to the output end of the supercritical hydrothermal synthesis module 11, receiving the high-temperature and high-pressure fluid coming out of the supercritical hydrothermal synthesis module 11.

[0063] Inside the first cooler 13, through the principle of heat exchange, the heat in the high-temperature fluid is transferred to the cooling medium, thereby reducing the temperature of the fluid.

[0064] The input end of the liquid-solid separator 14 receives the cooled fluid from the first cooler 13. Using liquid-solid separation technologies such as gravity sedimentation, filtration, and centrifugal separation, the copper powder in the fluid is separated from the liquid.

[0065] Specifically, the input end of the oxidation reactor 15 is further connected with a liquid oxygen output pipeline, and a liquid oxygen pump 6 and an air preheater 7 are provided on the liquid oxygen output pipeline.

[0066] Among them, the output end of the multi-way heat exchanger 16 is connected to a 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-way 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.

[0067] In this embodiment, the liquid oxygen pump 6 is used to pump out and pressurize liquid oxygen from the storage tank so as to transport it to the air preheater 7 and the oxidation reactor 15.

[0068] 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.

[0069] In the oxidation reactor 15, the preheated liquid oxygen is mixed with the fluid from the supercritical water gasification module 9 and undergoes an oxidation reaction under high-temperature conditions.

[0070] Specifically, a slag discharge device is provided at the second group output end of the coupling reaction device 8, and the slag discharge device includes a third cooler 20 and a lock hopper 21;

[0071] The input end of the third cooler 20 is connected to the second group gasification output end, and the output end of the third cooler 20 is connected to the input end of the lock hopper 21; a water injection pipeline and a slag discharge pipeline are further provided on the lock hopper 21; a water injection ball valve is provided on the water injection pipeline, and a slag discharge needle valve is provided on the slag discharge pipeline.

[0072] Specifically, the system further includes a second water output pipeline, and the output end of the second water output pipeline is connected to the input end of the supercritical water hydrothermal synthesis module 11 through the multi-way heat exchanger 16; a second water pump 3 is provided on the second water output pipeline for pumping water into the input end of the supercritical water hydrothermal synthesis module 11 through the second water output pipeline by means of the second water pump 3.

[0073] In summary, the present invention provides a system for coupling kitchen waste gasification-hydrothermal synthesis to prepare copper powder, integrating a supercritical water gasification reactor and a supercritical water hydrothermal synthesis reactor through a casing structure; the gasification products in the supercritical water gasification module 9 are separated into pure hydrogen through the palladium membrane 10, and the hydrogen flows into the supercritical water hydrothermal synthesis module 11 as a reducing agent, replacing expensive chemical reducing agents, effectively improving the effective utilization of kitchen waste slurry and realizing the utilization rate of waste-to-resource conversion. Wall heat transfer reduces system energy loss, speeds up the reaction rate, and improves the energy efficiency of the system. At the same time, the present invention uses the palladium membrane 10 to separate pure hydrogen into the supercritical water hydrothermal synthesis module 11, avoiding the introduction of impurities, and can realize the preparation of high-purity ultrafine copper powder.

[0074] Example 2

[0075] 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 system comprises the following steps:

[0076] 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;

[0077] 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 ℃;

[0078] 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.

[0079] The copper precursor solution pump 4 inputs the copper precursor solution (CuSO) at a pressure of 23-30 MPa. 4 、Cu(NO 3 ) 2 、Cu(HCOO) 2 Precursors such as copper and other precursors) and alkaline solution (modifiers such as NaOH and KOH) as particle modifiers enter the supercritical hydrothermal synthesis module 11. Water flows through the second water pump 3 at a pressure of 23-30 MPa through the second water output pipeline and flows into the supercritical hydrothermal synthesis module 11 after preheating through the multi-directional heat exchanger 16. Copper solution and alkaline solution as particle modifiers are reduced with pure hydrogen in the supercritical hydrothermal synthesis module 11 to obtain products, which 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.

[0080] ​The remaining gasification products in the supercritical water gasification module 9 are subjected to online ash separation, and the separated slag particles are transported to the third cooler 20 to be cooled to 25°C and then enter the lock hopper 21. When discharging slag from the lock hopper 21, the water injection ball valve is opened, water is injected into the lock hopper 21 to a certain pressure, and then the ball valve is closed. Subsequently, 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.

[0081] At the same time, the gas-liquid products after ash separation enter the oxidation reactor 15 for oxidation. At this time, the temperature in the oxidation reactor 15 is 800 - 1000°C. The oxidation products enter the multi-way heat exchanger 16 to provide heat for the preheated water, and then release heat in the second cooler 17. The cooled mixed products are separated by the gas-liquid separator 18 to obtain mixed gas and water.

[0082] In summary, for the usage method of the system for coupling kitchen waste gasification - hydrothermal synthesis to prepare copper powder provided in this embodiment, taking kitchen waste as the raw material, through the supercritical water gasification module 9 for gasification reaction, the efficient conversion and resource utilization of kitchen waste are realized. The pure hydrogen in the gasification products is used as a reducing agent for the preparation of copper powder in the supercritical hydrothermal synthesis module 11, forming a closed loop of resource recycling. Water enters the supercritical water gasification module 9 after being heated by the multi-way heat exchanger 16 through the first water output pipeline, which not only improves the water utilization efficiency but also reduces energy consumption. The application of the palladium membrane 10 separation technology in the present invention can efficiently separate pure hydrogen from the gasification products, ensuring the smooth progress of the subsequent reduction reaction. Copper solution and alkaline solution are used as particle modifiers, and through the pure hydrogen in the supercritical hydrothermal synthesis module 11 for reduction reaction, high-purity copper powder is prepared. The liquid-solid separation unit can effectively separate the copper powder from the reaction products, improving the purity of the copper powder.

[0083] 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 on the outermost layer of the coupling reaction device 8 for the start-up process of the system and is closed 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 the palladium membrane 10, so that the pure hydrogen in the hydrogen-rich synthesis gas generated by the supercritical water gasification of kitchen waste is separated and enters the supercritical hydrothermal synthesis module 11, and the pure hydrogen directly replaces the reducing agent to reduce high-purity ultrafine copper powder.

[0084] In the present invention, the supercritical water gasification module 9 of the coupling device directly transfers heat to the supercritical hydrothermal synthesis module 11, reducing the use of heat exchangers and lowering costs. Direct heat transfer can also reduce system energy losses and improve the energy efficiency of the system. This system converts low-grade waste into high-grade hydrogen, achieving a hydrogen conversion efficiency of 92% and realizing the conversion of waste into resources.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered by the protection scope 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 heating unit comprises a plurality of electric heating devices (12), wherein the plurality of electric heating devices (12) are wrapped and arranged on the outer side wall of the supercritical water gasification module (9); 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 gas-liquid 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 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).

3. 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).

4. 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.

5. 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).

6. 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).

7. 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.

8. 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).

9. 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 8, 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.

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