A high gravity-microwave assisted concentration device and method for elemental analysis of aqueous solutions

Abstract

The application relates to a high gravity-microwave assisted concentration device for water solution element analysis, which comprises an inner cavity, an outer cavity, a heat exchanger and a condensed liquid storage tank; a microwave generator is arranged in the inner cavity, an air inlet is arranged on the side wall, a flow guide plate is fixed on the inner side wall and can be rotated around the fixed shaft as the center, the microwave generator is arranged on the upper wall of the inner cavity and is close to the upper wall, a concentrated liquid discharge port is arranged at the bottom of the inner cavity, the outer cavity is fixed on the outer side of the inner cavity and completely wraps the inner cavity to form a sealed environment, a gap of 4cm-15cm is arranged between the outer cavity and the inner cavity, an inert gas pipeline connected with inert gas is fixed on the top of the outer cavity, and the bottom is connected with the concentrated liquid storage tank; one end of the heat exchanger is connected with the feeding port, the other end is connected with high-temperature steam of volatile liquid separated from the mixed fluid, and the bottom is connected with the condensed liquid storage tank. The device can shorten the concentration time and improve the concentration efficiency.

Description

Technical Field

[0001] This invention belongs to the field of pretreatment for elemental analysis of aqueous solutions, and specifically relates to a supergravity-microwave assisted concentration device and concentration method for pretreatment of aqueous solutions. Background Technology

[0002] Liquid concentration is a method of increasing the concentration of a solution by evaporating the solvent. In laboratory analysis, concentration is often used to evaporate excess water from aqueous solutions, thereby increasing the concentration of elements such as fluorine, chlorine, sulfur, iron, copper, and nickel, which were originally present in lower concentrations, facilitating analysis and detection. Existing aqueous solution concentration devices typically use evaporation concentration, which involves heating the surface of the object and then transferring heat to the liquid interior via heat conduction, achieving heating-evaporation and increasing the concentration of the aqueous solution. However, because aqueous solutions are usually complex, some components easily diffuse or are oxidized and denatured during evaporation, and some elements such as fluorine, chlorine, nitrogen, and iron are easily contaminated or lost during the evaporation process. Furthermore, the limited heating area of ​​the liquid during heating results in slow mass and heat transfer, leading to long heating and concentration times. Additionally, this concentration method requires heating and heat transfer of unnecessary heating devices, increasing heating time, energy consumption, and concentration costs, resulting in low concentration efficiency.

[0003] Hypergravity technology is a novel technique for enhancing multiphase flow and reaction processes. Due to its small equipment size, low energy consumption, flexible application, and high safety, it has significant application value in hypergravity gas-liquid mass transfer technology. Hypergravity technology utilizes hypergravity conditions to greatly increase the flow velocity of gas and liquid. Under conditions of high dispersion, strong mixing, and rapid interface renewal, the liquid and liquid come into full contact at extremely high relative velocities, enhancing the contact and mass transfer between the two phases, effectively promoting the separation process, and achieving highly efficient mass and heat transfer. Currently, the application of hypergravity technology abroad is mainly in distillation, removal and absorption of harmful substances, rotating electrochemical reactors and fuel cells, and rotating polymerization reactors. In China, research on the application of hypergravity technology started relatively late, and its current applications are mainly in the preparation of nanomaterials, enhanced dust removal and biochemical reactions, and deoxygenation of oilfield water injection. Therefore, the development potential of hypergravity technology in China is enormous.

[0004] In liquid heating, conventional methods such as steam heating and electric heating require a certain amount of time to reach a specific temperature. Microwave heating, however, uses high-frequency microwaves to directly act on water molecules, causing them to vibrate violently. This violent movement generates a large amount of heat energy without altering the water molecules themselves. Microwave heating can rapidly adjust the microwave power to the required value within seconds, heating the object to an appropriate temperature and ensuring uniform heating. Furthermore, microwave heating has very low inertia, allowing for rapid temperature control. Currently, no similar reports have been found in related patents or literature regarding this novel hypergravity-microwave-assisted concentration device and method.

[0005] Invention patent CN201510072678.5 relates to a microwave-type traditional Chinese medicine evaporation and concentration device and method. The prior art design includes a concentration device with an outer cylinder connected to a polytetrafluoroethylene (PTFE) bushing. A stirring paddle is installed inside the PTFE bushing for stirring. A microwave generator is connected circumferentially to the stirring chamber, and the microwave generator head is inserted into the stirring chamber. Although the prior art uses a stirring paddle to agitate the microwave-heated liquid, the stirring efficiency is low, and it has no significant effect on increasing the specific surface area of ​​the gas-liquid contact, resulting in minimal improvement in the liquid evaporation rate. Furthermore, the lack of a temperature control device makes it impossible to monitor the concentration process inside the device, affecting the concentration effect and rate. During the microwave concentration process, the liquid comes into contact with air without inert gas protection, making it easy for the components in the liquid to be oxidized or contaminated by the air at high temperatures.

[0006] Invention patent CN201410696066.9 relates to a microwave concentration device and method for chemical raw materials. The prior art design incorporates a microwave generator between the reactor and heat dissipation unit in the chemical raw material microwave concentration device, along with a bubble generating mechanism at the bottom of the reactor. The bubbles generated by the bubble generating mechanism stir the chemical raw material liquid in the reactor, and the liquid is then irradiated by the microwave generator to lower the final concentration temperature. However, the prior art uses a bubble generating mechanism for stirring the liquid, which has low efficiency, minimal effect on increasing the specific surface area of ​​the gas-liquid contact, and poor effect on improving the liquid evaporation rate. Furthermore, the liquid comes into contact with air during the concentration process without inert gas protection, making it susceptible to oxidation, contamination, or loss of components in the liquid during concentration.

[0007] Invention CN201821256175.9 relates to an evaporation and concentration system. The prior art design includes a heat exchanger, a hypergravity concentration device, and a vapor compression heat pump. The heat exchanger heats a mixture containing a volatile liquid. The hypergravity concentration device is connected to the heat exchanger and disperses the fluid using centrifugal force. The vapor compression heat pump is connected to both the hypergravity concentration device and the heat exchanger and uses mechanical vapor recompression to raise the temperature of the volatile liquid vapor to obtain high-temperature vapor. The concentration device in the prior art lacks gas protection measures. During the concentration process, some components are easily oxidized, contaminated, or lost at high temperatures; heat tends to accumulate during heating, causing localized excessively high or low temperatures; and the lack of a temperature control device makes it impossible to monitor the liquid temperature during concentration, easily leading to excessively high or low temperatures, affecting the concentration effect and efficiency.

[0008] Invention CN201810033947.0 relates to an apparatus and application method for microwave-hypergravity combined treatment of ammonia nitrogen wastewater from rare earth production. In the prior art apparatus, the bottom of the wastewater tank is connected to the liquid inlet of a microwave oven via a pump and a pipe. The heating liquid outlet at the bottom of the microwave oven is connected to a spray pipe located in the middle of the side of a hypergravity rotating packing bed via the pump and pipe. The hypergravity rotating packing bed contains rotating discs, each connected to a motor via a rotating pump. A mesh belt is installed between the rotating discs. The top of the hypergravity rotating packing bed has a gas outlet, the bottom has a liquid outlet, and the bottom side has an air inlet. The gas outlet is connected to a waste gas absorption bottle via an outlet pipe, the liquid outlet is connected to an absorption liquid tank via an outlet pipe, and the air inlet is connected to a blower via an inlet pipe. The comparison document shows that the device is not sealed inside, and a blower is used to send air into the device. The liquid is in close contact with the air at high temperature, which makes it very easy for the less stable components to be oxidized or contaminated. The liquid is first heated in a microwave oven and then sent to a high-gravity rotating packed bed for concentration. It is impossible to monitor the temperature change of the liquid during the concentration process. There is no temperature control design, which can easily lead to the liquid temperature being too high or too low during the concentration process, affecting the concentration effect and efficiency.

[0009] Invention CN201811010704.1 relates to a system and method for purifying industrial-grade lithium carbonate using centrifugal force. The system described in the prior art includes a carbonizer, a solid-liquid separation device, a microwave-coupled centrifugal device, and a centrifuge connected sequentially via pipelines. The centrifugal device contains a packed bed, while the output liquid contains solid products and clarified liquid. The solid substances easily clog the pores of the packed bed within the centrifugal device, affecting its normal operation and reducing concentration efficiency. Furthermore, the device lacks sealing and gas protection, making it highly susceptible to oxidation or contamination of some components.

[0010] Invention CN201811010704.1 relates to a system and method for purifying industrial-grade lithium carbonate using centrifugal force. In the prior art, the liquid inlet of the centrifugal device is connected to the outlet of the circulation tank, and the liquid outlet is connected to the inlet of the circulation tank, forming a circulation system. Because the liquid distributor inside the centrifugal device is inserted into the center of the packing material, the lignin-containing solid-liquid mixture diffuses outward within the packing material, easily causing blockage of the packing pores and affecting the centrifugal reaction effect. Furthermore, the gas inlet of the centrifugal reaction device uses oxygen or hydrogen as the reaction gas; if used for liquid concentration, this can easily cause the liquid to be oxidized, reduced, contaminated, or lost at high temperatures. Finally, the circulation tank lacks venting and pressure-stabilizing facilities, easily leading to excessively high or low internal pressure. Summary of the Invention

[0011] In view of the shortcomings of the above-mentioned technologies, the purpose of this invention is to provide a supergravity-microwave-assisted concentration device and method for elemental analysis of aqueous solutions, which can overcome the above-mentioned technical disadvantages, greatly shorten the concentration time, and improve the concentration efficiency. This device employs supergravity concentration, using supergravity to disperse the fluid into a film on a guide plate, increasing the mass and heat transfer area and shortening the concentration time. The device uses a closed system, protected by inert gas and with controllable temperature, avoiding contamination or loss of components during the concentration process. Microwave energy is used to directly act on water molecules, causing them to move violently, rub, and collide to generate heat, assisting in rapid heating of the solution and avoiding energy consumption from unnecessary heating devices.

[0012] This invention provides a gravity-microwave-assisted concentration device for elemental analysis of aqueous solutions, comprising: an inner cavity, an outer cavity, a heat exchanger, and a condensate storage tank; the inner cavity is equipped with a microwave generator, has an air inlet on its side wall, and a guide plate fixed on its inner side wall, inclined upward along the horizontal plane of the inner wall, which can rotate under gravity around a fixed axis; the microwave generator is located above the axis and close to the upper inner wall of the inner cavity; the bottom of the inner cavity is equipped with a concentrate outlet; the outer cavity is fixed to the outside of the inner cavity, completely enclosing the inner cavity to form a sealed environment; there is a 4cm-15cm gap between the outer cavity and the inner cavity; the top of the outer cavity is fixed with an inert gas pipeline connected to an inert gas, and the bottom is connected to the concentrate storage tank; one end of the heat exchanger is connected to the feed inlet, and the other end is connected to the high-temperature vapor of the volatile liquid separated from the mixed fluid, while the bottom is connected to the condensate storage tank.

[0013] This device improves upon the problems of long heating time, high energy consumption, and the need for unnecessary heating devices in traditional evaporation and concentration processes. It adopts microwave-assisted heating, where microwave energy acts directly on the molecules, resulting in rapid and uniform heating, high heating efficiency, and prevention of local overheating.

[0014] In the supergravity-microwave assisted concentration device of the present invention, the angle between the guide plate and the horizontal plane is preferably 10°-45°, and it is fan-shaped and inclined upward along the inner wall of the inner cavity. The extension line of the tail of the guide plate preferably passes through the axis of the inner cavity, and the tangential angle of the arc-shaped outer edge of the guide plate is preferably 10°-50°.

[0015] The internal cavity of the hypergravity concentrator is equipped with a fan-shaped guide plate. When the aqueous solution undergoes centrifugal motion under the action of hypergravity, it can be dispersed by the guide plate which is inclined upward along the horizontal plane. Since the guide plate is inclined upward along the centrifugal direction, it effectively reduces the motion resistance of the aqueous solution when it is dispersed by the guide plate under the action of hypergravity. It also improves the problem of small pores in the internal packing bed of hypergravity, which is prone to clogging after long-term use. It increases the gas-liquid contact area, improves the mass and heat transfer rate, and can shorten the concentration time to 10min-30min, thereby improving the concentration efficiency.

[0016] In the supergravity-microwave assisted concentration device of the present invention, the outer cavity is preferably made of metal, fixed on a fixed shaft, forming a sealed environment with the device pipeline, and filled with inert gas; the inner cavity and the outer cavity are preferably coaxial and centrally symmetrical cylindrical containers.

[0017] The hypergravity device is designed with a fixed outer cavity and a hypergravity-driven rotating concentration inner cavity. There is a certain gap between the inner and outer cavities, which is filled with inert gas. When the inner cavity is concentrated by hypergravity rotation, the inert gas enters from the air inlet on the side wall, and the entire interior of the device is filled with inert gas. This effectively avoids the problem of the liquid coming into contact with air during the concentration process, which could lead to the oxidation and contamination of some components.

[0018] In the supergravity-microwave assisted concentration device of the present invention, the inner cavity is preferably provided with three temperature measuring points (upper, middle, and lower); the outer surface of the outer cavity is preferably fixedly connected with a pressure gauge; and the condensate storage tank is preferably provided with a pressure gauge and an exhaust valve.

[0019] The concentration chamber is equipped with a temperature control point. The concentration temperature can be controlled by adjusting the microwave power. The heating inertia is small, and the temperature rise and fall can be quickly controlled to avoid the concentration effect being affected by excessively high or low temperatures.

[0020] In the supergravity-microwave assisted concentration device of the present invention, the aqueous solution storage tank is preferably connected to the inner cavity, and the aqueous solution storage tank is preferably connected to an inert gas pipeline. The pressure inside the aqueous solution storage tank is adjusted by a pressure regulating valve. Preferably, an inlet is provided, and the flow rate of the aqueous solution is adjusted by a mass flow meter.

[0021] By exchanging heat between the concentrated steam and the aqueous solution, the aqueous solution is preheated, thus enabling the reuse of steam heat, reducing energy consumption, and significantly saving the amount of condensate used, thereby reducing energy consumption, saving resources, and lowering economic costs.

[0022] In the supergravity-microwave assisted concentration device of the present invention, the filling gas and pressurizing gas inside the device are preferably selected from at least one of nitrogen and argon.

[0023] In the supergravity-microwave assisted concentration device of the present invention, the discharge rate of the aqueous solution storage tank is preferably 0.1L / min-0.3L / min.

[0024] In the supergravity-microwave assisted concentration device of the present invention, the rotational speed of the inner cavity is preferably 700 r / min-1300 r / min.

[0025] In the supergravity-microwave assisted concentration device of the present invention, the number of microwave generators is preferably 2-4.

[0026] This invention provides a method for gravity-microwave-assisted concentration using a gravity-microwave-assisted concentration device: Before concentration, the reactor is purged with inert gas through an inert gas pipeline to replace the air inside the device, filling it with inert gas. The aqueous solution in the storage tank enters the heat exchanger under the control of a mass flow meter, where it exchanges heat with hot steam. The preheated aqueous solution enters the inner cavity, where it is rapidly heated under microwave action. Under the influence of gravity, it is dispersed into small droplets, filaments, or films along the direction of liquid movement by a guide plate. Inert gas enters through the air inlet at the bottom of the inner cavity, carrying hot steam into the heat exchanger. After heat exchange with the aqueous solution, the hot steam is condensed and enters the condensate storage tank. Excess inert gas is discharged through the condensate storage tank's exhaust valve. The aqueous solution is preheated by the energy of the hot steam and enters the inner cavity for concentration. The concentrated liquid obtained in the inner cavity is transported to the concentrated liquid storage tank through the concentrated liquid outlet pipeline at the bottom. The temperature of the inner cavity is monitored by a temperature measuring point inside the reactor, and the heating power of the microwave generator is adjusted accordingly.

[0027] The beneficial effects of this invention are:

[0028] The device disclosed in this invention employs a supergravity concentration method, which disperses the fluid into a film on a guide plate using supergravity, thereby increasing the mass and heat transfer area and shortening the concentration time. The device uses a closed system with inert gas protection and controllable temperature to prevent contamination or loss of components during the concentration process. Microwave energy is used to directly act on water molecules, causing them to move and collide violently to generate heat, which helps the solution to heat up rapidly, avoiding unnecessary heating devices and thus improving concentration efficiency. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention;

[0030] Figure 2 This is a top view of the inner cavity of the supergravity concentration device of the present invention;

[0031] Among them: (1) feed inlet, (2) aqueous solution storage tank, (3) nitrogen line, (4) heat exchanger, (5) guide plate, (6) air inlet, (7) steam outlet, (8) condensate storage tank, (9) exhaust valve, (10) motor, (11) microwave generator, (12) inner cavity, (13) outer cavity, (14) concentrate storage tank, (15) aqueous solution inlet Detailed Implementation

[0032] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0033] Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and compounds are commercially available.

[0034] like Figure 1 As shown, the present invention provides a supergravity-microwave assisted concentration device for elemental analysis of aqueous solutions, comprising an inner cavity, an outer cavity, and a heat exchanger.

[0035] The preheated aqueous solution inlet 15 above the inner cavity 12 is connected to the heat exchanger 4. The concentrated liquid outlet pipeline is located below the inner cavity 12, passing through the outer cavity 13 and connecting to the concentrated liquid storage tank 14. An air inlet 6 is located on the side wall of the inner cavity 12, and a microwave generator 11 is installed on the upper wall of the inner cavity 12. A hot steam outlet 7 is connected to the heat exchanger 4, which is connected to the aqueous solution storage tank 2. The aqueous solution flow rate is regulated by a mass flow meter. A condensate storage tank 8 is connected below the heat exchanger 4, and a pressure gauge and an exhaust valve 9 are connected to the condensate storage tank 8. A guide plate 5, angled upwards from the horizontal plane, is located on the inner side wall of the inner cavity 12. An inert gas pipeline 3 is connected above the aqueous solution storage tank 2. The inner cavity 12 is encased in an insulated outer cavity 13. The inert gas pipeline 3 and a pressure gauge are connected above the insulated outer cavity 13, and a concentrated liquid outlet pipeline, connected to the concentrated liquid storage tank 14, is located below it.

[0036] Raw material source: In this embodiment, the aqueous solution containing chloride ions, sulfate ions, and phosphate ions is derived from a crude chemical product obtained from a pilot plant of the Daqing Chemical Research Center, which is then separated by water extraction; the wastewater containing heavy metals such as iron, chromium, and nickel also comes from the aforementioned plant.

[0037] Evaluation and analysis methods: The anion content in the aqueous solution was determined using a Metrohm 940 ion chromatograph (Switzerland), and the heavy metal content in the aqueous solution was determined using a Pepperl 5300DV inductively coupled plasma atomic emission spectrometer (PES). Specific implementation examples:

[0039] Before concentration, the reactor needs to be purged with inert gas from inert gas pipeline 3 to replace the air inside the device and fill it with inert gas. After purging, the aqueous solution in the aqueous solution storage tank 2 enters the heat exchanger 4 under the control of a mass flow meter. In the heat exchanger 4, it exchanges heat with hot steam. The preheated aqueous solution enters the inner cavity 12 through the aqueous solution inlet 15, where it is rapidly heated by microwaves and concentrated by being dispersed into small droplets, liquid filaments, or liquid films by the guide plate 5 under the influence of gravity. The temperature of the inner cavity is monitored by the temperature measuring point inside the reactor, and the heating power of the microwave generator 11 is adjusted accordingly. The hot steam obtained from evaporating the liquid enters the heat exchanger 4 through the hot steam outlet 7, exchanges heat with the aqueous solution from the aqueous solution storage tank 2, and then condenses into liquid, entering the condensate storage tank 8. The space between the outer cavity 13 and the inner cavity 12 is filled with an inert gas atmosphere. A pressure gauge is installed on the outer cavity 13, and the pressure inside the device is maintained stable by adjusting the inert gas valve. The concentrate in the inner cavity is delivered to the concentrate storage tank 14 through the concentrate outlet pipeline passing under the inner and outer cavities.

[0040] In one operation of this embodiment, the apparatus was purged with nitrogen under normal pressure to replace the air. 2.5L of an aqueous solution containing a certain concentration of chloride, sulfate, and phosphate ions was transferred to an aqueous solution storage tank. Under normal pressure, the internal chamber temperature was 94℃-96℃, the internal chamber rotation speed was 1100 r / min, and the discharge rate from the aqueous solution storage tank was 0.2L / min. After 4 minutes, the discharge rate was adjusted to 0.1L / min, and concentration was continued for another 17 minutes, resulting in 1.52L of concentrated solution. This embodiment yielded a high-concentration concentrate. The concentrations of chloride, sulfate, and phosphate ions in the concentrate were detected by ion chromatography without loss of concentration.

[0041] In another operation of this embodiment, the apparatus was purged with nitrogen under normal pressure to replace the air. 3.0 L of wastewater containing iron, chromium, and nickel was placed in an aqueous solution storage tank. Under normal pressure, the internal chamber temperature was 95℃-97℃, the internal chamber rotation speed was 1000 r / min, and the discharge rate from the aqueous solution storage tank was 0.15 L / min. After 4 minutes, the discharge rate was adjusted to 0.08 L / min, and concentration was continued for another 30 minutes, resulting in 1.37 L of concentrated solution. Through the operation of this embodiment, concentrated heavy metal wastewater was obtained, and the iron, chromium, and nickel content was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) without loss of concentration.

[0042] In summary, the device of the present invention adopts a supergravity concentration method, which disperses the fluid into a film on the guide plate by supergravity, thereby increasing the mass and heat transfer area and shortening the concentration time. The device adopts a closed system, protected by inert gas and with controllable temperature, to avoid contamination or loss of components during the concentration process. Microwave energy is used to directly act on water molecules, causing them to move and collide violently to generate heat, which helps the solution to heat up rapidly and avoids the energy consumption of heating devices that are not necessary.

[0043] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the present invention.

Claims

1. A centrifugal-microwave assisted concentration device for elemental analysis of aqueous solutions, characterized in that, The device includes: an inner cavity, an outer cavity, a heat exchanger, and a condensate storage tank; The inner cavity is equipped with a microwave generator, and has an air inlet on the side wall. A guide plate that is inclined upward along the horizontal plane of the inner wall is fixed on the inner side wall. The inner cavity rotates under supergravity around a fixed axis. The microwave generator is located above the axis and close to the upper inner wall of the inner cavity. The bottom of the inner cavity is equipped with a concentrated liquid outlet. The outer cavity is fixed and located outside the inner cavity, completely enclosing the inner cavity to form a sealed environment. There is a 4cm-15cm gap between the outer cavity and the inner cavity. An inert gas pipeline connected to an inert gas is fixed at the top of the outer cavity for filling the gap with inert gas. The bottom of the inner cavity is connected to a concentrated liquid storage tank. One end of the heat exchanger is connected to the outlet of the aqueous solution storage tank, and the other end is connected to the hot vapor of the volatile liquid separated from the mixed fluid in the inner cavity. At the same time, a condensate storage tank is connected to the bottom. The aqueous solution in the aqueous solution storage tank enters the heat exchanger and exchanges heat with the hot vapor. The preheated aqueous solution enters the inner cavity, and the hot vapor is condensed into liquid and enters the condensate storage tank. The guide plate has an angle of 10°-45° with the horizontal plane, and is fan-shaped, tilting upwards along the inner wall of the inner cavity. The extended line of the tail of the guide plate passes through the axis of the inner cavity, and the tangential angle of the arc-shaped outer edge of the guide plate is 10°-50°. When the aqueous solution undergoes centrifugal motion under the action of hypergravity, it is dispersed by the guide plate tilting upwards along the horizontal plane. Since the guide plate is tilted upwards along the centrifugal direction, it effectively reduces the motion resistance of the aqueous solution when it is dispersed by the guide plate under the action of hypergravity. Under the action of hypergravity, the solution is dispersed into small droplets, liquid filaments, or liquid films along the direction of liquid movement by the guide plate. The rotational speed of the inner cavity is 700 r / min-1300 r / min.

2. The centrifugal-microwave assisted concentration device for elemental analysis of aqueous solutions according to claim 1, characterized in that: The outer cavity is made of metal and is fixed on a fixed shaft; The inner cavity and the outer cavity are coaxial and centrally symmetrical cylindrical containers.

3. The centrifugal-microwave assisted concentration device for elemental analysis of aqueous solutions according to claim 1, characterized in that: The inner cavity is equipped with three temperature measuring points: upper, middle, and lower. A pressure gauge is fixedly connected to the outer surface of the outer cavity. The condensate storage tank is equipped with a pressure gauge and an exhaust valve.

4. The supergravity-microwave assisted concentration device for elemental analysis of aqueous solution according to claim 1, wherein the aqueous solution storage tank is connected to the inner cavity, an inert gas pipeline is connected to the aqueous solution storage tank, the pressure inside the aqueous solution storage tank is adjusted by a pressure regulating valve, and an inlet is provided, wherein the flow rate of the aqueous solution is adjusted by a mass flow meter.

5. The centrifugal-microwave assisted concentration device for elemental analysis of aqueous solutions according to claim 1, characterized in that: The filling gas and pressurizing gas inside the device are selected from at least one of nitrogen or argon.

6. The centrifugal-microwave assisted concentration device for elemental analysis of aqueous solutions according to claim 1, characterized in that: The discharge rate of the aqueous solution storage tank is 0.1L / min-0.3L / min.

7. The centrifugal-microwave assisted concentration device for elemental analysis of aqueous solutions according to claim 1, characterized in that: The number of microwave generators is 2-4.

8. The method for centrifugal-microwave assisted concentration using a centrifugal-microwave assisted concentration apparatus for elemental analysis of aqueous solutions as described in any one of claims 1-7, characterized in that: Before concentration, inert gas is used to purge the outer and inner cavities with inert gas from the inert gas pipeline, replacing the air in the device and filling the interior with inert gas. The aqueous solution in the aqueous solution storage tank enters the heat exchanger under the control of the mass flow meter, where it exchanges heat with hot steam. The preheated aqueous solution enters the inner cavity, where it is rapidly heated by microwaves and dispersed into small droplets, liquid filaments, or liquid films by the guide plate under the influence of gravity along the direction of liquid movement. Inert gas enters through the air inlet at the bottom of the inner cavity, carrying hot steam into the heat exchanger. After exchanging heat with the aqueous solution, the hot steam is condensed and enters the condensate storage tank. Excess inert gas is discharged through the condensate storage tank exhaust valve. The aqueous solution is preheated by the energy of the hot steam and enters the inner cavity for concentration. The concentrated liquid obtained in the inner cavity is transported to the concentrated liquid storage tank through the concentrated liquid outlet pipeline at the bottom. Temperature measuring points in the inner cavity monitor the temperature of the inner cavity and are used to adjust the heating power of the microwave generator.

Images