Device for preparing nano powder through flame spray pyrolysis

Abstract

The utility model relates to the technical field of nano-particle liquid phase collecting devices, in particular to a device for preparing nano-powder through flame spray pyrolysis, which comprises a combustor, a flame combustion chamber, a precursor atomizer, a liquid phase collector and a suction mechanism. The precursor solution is subjected to high-temperature atomization and then is combusted through auxiliary flames to generate nano-particles and tail gas, the rear end of the flame combustion chamber is connected into a liquid phase collector, and the liquid phase collector is provided with a collecting liquid, a porous membrane substrate and a cooling device and used for filtering and collecting the nano-particles generated by combustion of the precursor solution; by means of a suction mechanism, tail gas containing nano-particles is subjected to micro-bubbling through a porous membrane matrix and then makes contact with collected liquid, then solid nano-particle flow is captured, and liquid-phase collection of nano-powder synthesized at the high temperature is achieved. According to the device, the problems of discontinuity, dissipation and low efficiency in the nano-particle trapping process are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to nanometer particle liquid phase collection device technical field, concretely is a kind of device for flame spray pyrolysis preparation nanometer powder. BACKGROUND

[0002] Functional nanometer powder material is the core raw material of high-end manufacturing industry, has extensive application demand in energy material, high-end optics, electronic device and biomedical field, but nanometer material has the problems of preparation difficulty and high processing cost for a long time, how to realize stable, controllable preparation specific morphology and structure nanometer powder material is still a challenge.Flame spray pyrolysis synthesis method is a common new type of nanometer material preparation method, and flame spray pyrolysis synthesis method is more widely used in the preparation of nanometer material due to its simple one-step synthesis process.

[0003] In the flame spray pyrolysis device, the precursor liquid is atomized into small droplets and then enters the flame chamber to generate nanoparticles, the generated nanoparticles rise with high-speed airflow, and adhere to the filter collector under the negative pressure action of the suction mechanism, when the preparation of nanoparticles is completed, only the nanoparticles adhered to the filter collector are collected. However, the particles generated by flame spray pyrolysis are mainly several nanometers or tens of nanometers, due to the strong thermophoresis and Brownian diffusion of particles, it is difficult for nanometer particles to be constrained along the streamline, in the actual operation process, the generated nanoparticles will be obviously attached to the inner wall surface of the reaction chamber, resulting in particle escape loss, and the powder collection difficulty is increased, thereby reducing the collection efficiency, and the cost of nanometer particle collection is increased. In addition, the filter collector is composed of multiple layers of fibers or porous materials, however, the multiple layers of fibers or porous materials are polluted by the accumulation of particles on the surface and internal pores, further causing the collection efficiency to be reduced and the filter device to be replaced or cleaned regularly, the collection process is not sustainable, which fundamentally limits the efficiency and service life of such filter device. Therefore, it is urgent to design a high-efficiency collection device for 1-100 nanometer particles to improve the collection efficiency of nanometer particles. UTILITY MODEL CONTENTS

[0004] The problem to be solved is to provide a high-efficiency collection device for 1-100 nanometer particles to improve the collection efficiency of nanometer particles.

[0005] To achieve the above object, the utility model provides the following technical scheme: a device for flame spray pyrolysis preparation nanometer powder, including combustor, flame combustion chamber, suction mechanism, the flame combustion chamber connects combustor and suction mechanism, still be equipped with liquid phase collector between the flame combustion chamber and suction mechanism, the liquid phase collector is connected the flame combustion chamber through the connecting pipeline, the periphery of liquid phase collector is provided with cooling device, and the liquid phase collector internally contains porous membrane matrix and collection liquid, the pore size of porous membrane matrix is micron level, and the porous membrane matrix is sealedly connected at the outlet of connecting pipeline and is located below the collection liquid level.

[0006] Preferably, the porous membrane matrix material is one of stainless steel porous membrane, nonmetal porous membrane, ceramic porous membrane and composite material porous membrane, and a hydrophobic or hydrophilic film is deposited on the surface thereof.

[0007] Preferably, the pore size of the porous membrane matrix is 0.01mm-1mm, and the pore size height is 0.1-20mm.

[0008] Preferably, the collection liquid is one of organic liquid, water-based liquid and water-oil mixed liquid. Preferably, a safety bottle is arranged between the liquid phase collector and the suction mechanism.

[0009] Preferably, the outlet of the connecting pipeline is a pipeline outlet, and a drainage plate is arranged between the pipeline outlet and the porous membrane matrix, so that the tail gas flow uniformly flows downward.

[0010] Preferably, the cooling device is set to a temperature of 0-15 DEG C.

[0011] Compared with the prior art, the utility model provides a device for flame spray pyrolysis preparation nanometer powder, which has the following beneficial effects:

[0012] 1. The liquid phase collector of the utility model utilizes the collection liquid and the porous membrane matrix, and when the gas containing nanometer powder passes through the porous membrane matrix, bubbles are generated, and before the bubbles break, the nanometer particles contact the gas-liquid interface, so that the nanometer particles are captured by the gas-liquid interface, realizing efficient nanometer particle collection.

[0013] 2. The utility model has the advantages of high nanometer particle collection efficiency, low fluid resistance, strong processing capacity, energy saving and easy commercialization.

[0014] 3. The liquid phase collector of the utility model can replace the filter membrane and be used continuously for a long time.

[0015] 4. The porous membrane matrix of the utility model has low cost, is easy to clean and has simple structure.

[0016] 5. The utility model discloses need not to carry out the improvement to flame spray pyrolysis equipment, can directly through the clamp connection existing equipment, can better match the existing flame spray pyrolysis synthesis nanoparticle device, and installation is simple and convenient. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is the structure diagram of the nanoparticle collection device of the preferred embodiment of the utility model;

[0018] Figure 2 is the structure diagram of the porous membrane matrix in liquid phase of the preferred embodiment of the utility model;

[0019] Figure 3 is the transmission electron microscope diagram of titanium doped cerium dioxide nanoparticle of the preferred embodiment of the utility model;

[0020] The figure mark explains: 1, combustor, 2, flame combustion chamber, 3, intercommunication pipeline, 31, pipeline export, 32, drainage plate, 4, liquid collector, 41, porous membrane matrix, 42, collection liquid, 43, cooling device, 5, safety bottle, 51, buffer tube, 6, suction mechanism, 7, porous plate. DETAILED DESCRIPTION

[0021] The technical scheme in the embodiments of the utility model will be described below with reference to the drawings in the embodiments of the utility model:

[0022] The collection of nanoparticles in the prior art is to install a porous membrane collecting plate on the upper portion of the flame combustion chamber 2, which belongs to solid phase collection, and this method has the problem of low collection efficiency as described in the background art. In view of the above defects, an improved demand is proposed, and the utility model provides a device for preparing nanometer powder by flame spray pyrolysis, which solves the problems of discontinuity, nanoparticle escape and low collection efficiency in the traditional solid phase porous membrane collection of 1-100 nanometer particles. The device comprises a burner 1, a flame combustion chamber 2 and a suction mechanism 6. The burner 1 is a device for supporting flame by mixing and burning gas. The flame combustion chamber 2 is a space for synthesizing nanoparticles by flame spray pyrolysis. The precursor atomized liquid is combusted by the burner 1 to generate nanoparticles in the flame combustion chamber 2. Instead of the existing collection method of installing a porous membrane collecting plate on the upper portion of the flame combustion chamber 2, a liquid phase collector 4 is arranged between the flame combustion chamber 2 and the suction mechanism 6, and the liquid phase collector 4 is connected to the flame combustion chamber 2 through a communication pipeline 3. The communication pipeline 3 is in the form of a variable diameter pipeline and is arranged on the upper portion of the flame combustion chamber 2. The main function is to converge the nanoparticles and tail gas generated in the flame combustion chamber 2 and then suck them into the liquid phase collector 4 through the suction mechanism 6 arranged at the end. The lower end of the burner 1 is connected to the gas and the precursor atomized liquid. The precursor atomized liquid is combusted in the flame combustion chamber 2 to generate nanoparticles and tail gas. A ring-shaped porous plate 7 is embedded in the bottom of the burner 1. The porous plate 7 is fixed between the inner wall of the flame combustion chamber 2 and the outer wall of the burner 1. The porous plate 7 is used to filter air to prevent external particulate pollutants from entering. On the other hand, the gas flow is used to sweep the inner wall of the flame combustion chamber 2 to prevent nanoparticles from adhering to the surface of the inner wall of the flame combustion chamber 2. A cooling device 43 is arranged on the periphery of the liquid phase collector 4. The temperature of the cooling device 43 is set to 0-15 DEG C for cooling the liquid phase collector 4. The liquid phase collector 4 contains a porous membrane matrix 41 and a collecting liquid 42. The pore size of the porous membrane matrix 41 is micrometer level. The porous membrane matrix 41 is sealingly connected to the outlet of the communication pipeline 3 and is located below the liquid level of the collecting liquid 42. The principle of collecting nanoparticles by the liquid phase collector 4 is that the key to capturing particles by the gas-liquid interface is that they can contact the gas-liquid interface before the bubble breaks, and the stopping distance of the particles is greater than the diameter of the bubble, which indicates that the particles have enough time to move to the gas-liquid interface before the bubble breaks. When the nanoparticles contact the gas-liquid interface, whether the particles are hydrophobic or hydrophilic, they will be captured by the functional liquid and cannot escape into the gas. Finally, the nanoparticles are intercepted by the liquid, and the gas is discharged. The tail gas containing nanoparticles reaches the porous membrane matrix 41 from the flame combustion chamber 2 through the communication pipeline 3. After the tail gas is micro-bubbled by the porous membrane matrix 41, it contacts the collecting liquid 42 to capture the solid nanoparticle flow, thereby realizing the filtration and collection of the nanoparticles generated by combustion.According to the different nano-materials, the porous membrane matrix 41 can be made of stainless steel porous membrane, non-metallic porous membrane, ceramic porous membrane and composite porous membrane, and the surface of the porous membrane matrix 41 is deposited with a hydrophobic or hydrophilic film. The pore size of the porous membrane matrix 41 is 0.001 mm to 1 mm, and the pore size height is 0.1 to 20 mm. The collection liquid 42 can be one of organic liquid, water-based liquid and water-oil mixed liquid; and one or more of functional complexing agent, surfactant, adsorbent and reducing agent is added to the collection liquid 42.

[0023] Since the gas discharged from the liquid collector 4 contains moisture, in order to avoid the moisture entering the suction mechanism 6, a safety bottle 5 is arranged between the liquid collector 4 and the suction mechanism 6, and a buffer tube 51 is connected between the liquid collector 4 and the safety bottle 5. One end of the buffer tube 51 is located at the top of the liquid collector 4 and does not contact the liquid level of the collection liquid 42. On the other hand, the safety bottle 5 can prevent the collection liquid 42 from being sucked into the suction mechanism 6.

[0024] In some embodiments, a drainage plate 32 is arranged between the pipeline outlet 31 and the porous membrane matrix 41 to make the tail gas flow uniformly downward. The shape and size of the porous membrane matrix 41 are matched with the connecting pipeline 3. The pipeline outlet 31, the drainage plate 32 and the porous membrane matrix 41 are sealingly connected. The sealing mode is realized by sealing glue or buckle structure. The shape of the pipeline outlet 31 is one of cylindrical, gradually expanding cylindrical or polygonal column.

[0025] As shown in Figure 2 The porous membrane matrix 41 is made of ceramic round sheet, and the porous membrane matrix 41 has micron-level pores.

[0026] The process of preparing cerium dioxide nano-powder by using the device of the present application is as follows:

[0027] I. Preparation of precursor liquid: 2.3 g of cerium carbonate is mixed with 50 mL of propionic acid, 100 μL of deionized water is added, and then heated to 130°C under magnetic stirring to completely dissolve it. After cooling to room temperature, 50 mL of a mixture of methanol-water with a mass ratio of 5.2:1 is added to obtain a precursor mixture.

[0028] II. Flame spray pyrolysis synthesis and liquid collection: the precursor atomized liquid is sent to the supporting flame of the flame spray pyrolysis equipment at a rate of 3 mL / min after heating and atomization by using a high-pressure infusion pump. The supporting flame is formed by mixing and burning methane and oxygen with a flow rate of 0.5 L / min in the burner 1, and the flow rate of the supporting oxygen of the precursor atomized liquid is 2.5 L / min. The combustion products and tail gas flow into the liquid collector 4 through the suction mechanism 6, and the nano-powder suspension is obtained by intercepting and filtering through the collection liquid 42. The suspension is centrifuged and dried to obtain the target powder product.

[0029] The process for preparing the titanium-doped ceria nano-powder using the device is as follows:

[0030] I. Preparation of the precursor liquid: 2.3 g of cerium carbonate is mixed with 50 mL of propionic acid, 100 μL of deionized water is then added, and then the mixture is heated to 130℃ under magnetic stirring until it is completely dissolved, and then the mixture is cooled to room temperature, 50 mL of a mixture of methanol and water with a mass ratio of 5.2:1 is added, and then 0.4 g of titanium (IV) (triethanolamine acid) isopropanol is added to obtain a precursor mixture.

[0031] II. Flame spray pyrolysis synthesis and liquid phase collection: the precursor atomized liquid is sent to the supporting flame of the flame spray pyrolysis device at a rate of 3 mL / min by using a high-pressure infusion pump, the supporting flame is formed by mixing and burning methane and oxygen with a flow rate of 0.5 L / min in the burner 1, the flow rate of the supporting oxygen for the precursor atomized liquid is 2.5 L / min, the combustion products and tail gas are flowed into the liquid phase collector 4 by the suction mechanism 6, the nanometer powder suspension is obtained by intercepting and filtering the collected liquid 42, and the target powder product is obtained by centrifugal drying.

[0032] Figure 3 The transmission electron microscope image of the titanium-doped ceria nano-particles collected by the liquid phase collector 4 is shown, and the particle size of the nano-particles is about 20-50 nm.

[0033] The above examples are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

Claims

1. A device for preparing nanopowders by flame spray pyrolysis, comprising a burner (1), a flame combustion chamber (2), and a suction mechanism (6), wherein the flame combustion chamber (2) is connected to the burner (1) and the suction mechanism (6), and is characterized in that: A liquid phase collector (4) is further provided between the flame combustion chamber (2) and the suction mechanism (6), and the liquid phase collector (4) is connected to the flame combustion chamber (2) via a connecting pipe (3); a cooling device (43) is provided on the periphery of the liquid phase collector (4), and a porous membrane matrix (41) and a collection liquid (42) are accommodated inside the liquid phase collector (4), wherein the pore size of the porous membrane matrix (41) is in the micron order, and the porous membrane matrix (41) is sealed and connected to the outlet of the connecting pipe (3) and is located below the liquid level of the collection liquid (42).

2. The device for preparing nanopowders by flame spray pyrolysis according to claim 1, wherein: The porous membrane matrix (41) is made of a material selected from the group consisting of a stainless steel porous membrane, a non-metallic porous membrane, a ceramic porous membrane and a composite porous membrane, and a hydrophobic or hydrophilic film is deposited on its surface.

3. The device for preparing nanopowders by flame spray pyrolysis according to claim 2, wherein: The porous membrane matrix (41) has a pore size of 0.01 mm to 1 mm and a pore height of 0.1 to 20 mm.

4. The device for preparing nanopowders by flame spray pyrolysis according to claim 3, wherein: The collection liquid (42) is one of an organic liquid, a water-based liquid and a water-oil mixed liquid.

5. The device for preparing nanopowder by flame spray pyrolysis according to any one of claims 2 to 4, characterized in that: A safety bottle (5) is provided between the liquid phase collector (4) and the suction mechanism (6).

6. The device for preparing nanopowders by flame spray pyrolysis according to claim 5, characterized in that: The outlet of the connecting pipeline (3) is a pipeline outlet (31), and a guide plate (32) is provided between the pipeline outlet (31) and the porous membrane matrix (41). The guide plate (32) allows the exhaust gas to flow evenly downward.

7. The device for preparing nanopowders by flame spray pyrolysis according to claim 1, characterized in that: The temperature of the cooling device (43) is set to 0° to 15°.

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