Powder storage device

Abstract

To provide a powder storage device that suppresses dust explosions.SOLUTION: A powder storage device 1 comprises: a silo container 100 storing powders 104; and an injection part 300 injecting at least one selected from the group consisting of an inert gas, ions, and mist into the silo container 100.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This invention relates to a powder storage device and its dust explosion prevention system.

Background Art

[0002] Conventionally, a silo is disclosed in, for example, Japanese Patent Application Laid-Open No. 2018-185264 (Patent Document 1). Patent Document 1 discloses a suction hose hanging from the upper part of a silo, and a suction hose length adjustment device that adjusts the length of the suction hose so that the suction port of the suction hose is located near the surface of the stored material based on the height information of the stored material stored in the silo, and a gas sensor that detects the concentration of a predetermined component in the gas sucked by the suction hose.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is a problem that an explosion accident may occur in a conventional silo.

Means for Solving the Problems

[0005] The powder storage device includes a silo container for storing powder, and an injection part for injecting at least one selected from the group consisting of an inert gas, ions, and mist into the silo container.

[0006] The powder storage device configured as described above can suppress dust explosion in the silo container because an inert gas or the like is injected into the silo container.

[0007] Preferably, the system further includes a control unit that adjusts the injection amount of at least one selected from the group consisting of inert gas, ions, and mist, and a storage unit that stores a function necessary for adjusting the injection amount.

[0008] In this case, the injection amount is adjusted according to the function stored in the memory unit, allowing for effective control of the injection amount.

[0009] Preferably, the control unit adjusts the injection amount according to the type of powder and the total volume of the powder. In this case, dust explosions can be effectively suppressed.

[0010] Preferably, the control unit adjusts the injection amount according to the type of powder and the moisture content of the powder. In this case, dust explosions can be effectively suppressed.

[0011] Preferably, the control unit adjusts the injection amount according to the type and particle size of the powder. In this case, dust explosions can be effectively suppressed.

[0012] Preferably, the control unit adjusts the injection amount according to the type of powder and the humidity at the time of injection. In this case, dust explosions can be effectively suppressed.

[0013] Preferably, the control unit adjusts the injection amount according to the explosive limit concentration of the powder. Preferably, the control unit adjusts the injection amount according to the statistically minimum ignition energy of the powder. do.

[0014] Preferably, the control unit adjusts the injection amount according to the limit oxygen concentration of the powder. The dust explosion prevention system according to this invention is a dust explosion prevention system for a powder storage device that implements a neural network using an information processing device, wherein the powder storage device comprises a silo container for storing powder and an injection unit for injecting at least one selected from the group consisting of inert gas, ions, and mist into the silo container, and the dust explosion prevention system for the powder storage device comprises an input layer and an output layer, wherein the input data of the input layer is set to at least one of a plurality of risk factors related to powder dust explosion when powder is put into the silo container, and the output data of the output layer is set to a future time from the time of powder input. The system comprises a neural network for determining the probability of a dust explosion occurring in the silo container, a machine learning unit for training the neural network using actual values ​​of the input data and output data as training data, an estimation unit for inputting the input data with the current time as the reference time to the neural network trained by the machine learning unit and obtaining an estimated future value based on the output data with the current time as the reference time, and a control unit for determining the amount to be injected from the injection unit according to the estimated value of the estimation unit, wherein the risk factors are the type of powder, the total volume of the powder, the moisture content of the powder, the particle size of the powder, and the humidity at the time of powder input.

[0015] The dust explosion prevention system for powder storage devices, configured in this way, can determine the injection amount with high accuracy by using a neural network to estimate future values. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic diagram of a powder storage device according to the embodiment. [Figure 2] This is a detailed diagram of a powder storage device according to the embodiment. [Figure 3] This graph shows the relationship between the total volume of powder and the amount of gas or other substances injected. [Figure 4] This graph shows the relationship between the moisture content of the powder and the amount of gas or other substances injected. [Figure 5] This graph shows the relationship between powder particle size and the amount of gas or other substances injected. [Figure 6]It is a graph showing the relationship between the humidity at the time of powder input and the injection amount of gas or the like. [Figure 7] It is a graph showing the relationship between the explosion limit concentration of powder and the injection amount of gas or the like. [Figure 8] It is a graph showing the relationship between the statistical minimum ignition energy of powder and the injection amount of gas or the like. [Figure 9] It is a graph showing the relationship between the limiting oxygen concentration of powder and the injection amount of gas or the like.

Mode for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Configuration of the device) FIG. 1 is a schematic diagram of a powder storage device according to an embodiment. As shown in FIG. 1, a powder storage device 1 according to an embodiment includes a silo container 100 for storing powder, and an injection unit 300 for injecting at least one selected from the group consisting of inert gas, ions, and mist into the silo container.

[0018] The powder storage device 1 includes a charging unit 200 for charging powder into the silo container 100. The powder storage device 1 includes a control unit 400 for controlling the flow rate, injection timing, etc. of gas or the like injected from the injection unit 300, and a storage unit 500 for storing data used for the calculation of the control unit 400.

[0019] The silo container 100 has a cylindrical shape, a tubular state such as each cylindrical shape. The inner diameter does not necessarily have to be constant, and the inner diameter may change according to the height. The volume of the silo container 100 is not particularly limited.

[0020] Powder is stored in the silo container 100. Examples of the pellets ( powder) stored in the silo container 100 include foods such as wheat, barley, rye, corn, soybeans, adzuki beans, soybean meal, etc., and industrial products such as alumina, coal, tire chips, wood chips, straw, etc.

[0021] The input section 200 is located at the top of the silo container 100. The input section 200 drops the powder into the silo container 100, for example, by gravity. However, the powder may be introduced into the silo container 100 from the input section 200 not only by gravity, but also by means of a screw. When using power such as a screw, the input section 200 does not necessarily have to be located at the top of the silo container 100, but may be located on the side or bottom of the silo container 100.

[0022] The injection unit 300 is a device for injecting gas, ions, mist, etc., into the silo container 100. The injection unit 300 may include a nozzle provided inside the silo container 100. The injection unit 300 injects an inert gas such as nitrogen or carbon dioxide into the silo container 100 to suppress dust explosions inside the silo container 100.

[0023] If plants such as fir trees are placed inside the silo container 100, the fir trees will respire even during storage. This consumes oxygen and generates carbon dioxide. As a result, the air inside the silo container 100 becomes thin, leading to an oxygen-deficient state. When entering the silo container 100 for inspection or other purposes, the oxygen concentration should be measured with an oxygen concentration meter. A concentration of 18% or higher is safe, but a level below this will result in oxygen deficiency. To prevent this, oxygen may be supplied from the injection port 300 to raise the oxygen concentration inside the silo container 100 to 18% or higher. In other words, the injection port 300 may inject not only an inert gas to prevent dust explosions, but also oxygen gas or air to enable workers to work inside the silo container 100.

[0024] Ions may be injected into the silo container 100 from the injection section 300. Injecting ions can neutralize static electricity from each powder, reducing the risk of dust explosion. As a device for generating such ions, for example, the SJ-E series hybrid ultra-high-speed sensing ionizer manufactured by Keyence Corporation can be used. When injecting ions, the gas composition inside the silo container 100 does not change compared to when gas is injected as described above, making it ideal for storing powders (such as rice hulls) where the gas composition inside the silo container 100 needs to be controlled. Furthermore, both gas and ions may be injected from the injection section 300.

[0025] Mist may be injected from the injection section 300. The mist can be manufactured, for example, by the "Mecha Swing Nozzle" series or "Water Mist" manufactured by Galyu Co., Ltd. It is preferable to use mist for powders that do not experience problems such as corrosion even when moisture adheres to them.

[0026] The control unit 400 is a device for controlling the flow rate, flow velocity, and injection timing of gas, ions, mist, etc., injected from the injection unit 300. The control unit 400 includes, for example, a computer.

[0027] The storage unit 500 stores tables used for control in the control unit 400. The storage unit 500 may be the hard disk of the computer that constitutes the control unit 400. The storage unit 500 may be a recording medium that can be detached from the computer. Examples of recording media include DVD-RAM, DVD-ROM, CD-ROM, FD, Examples of media that permanently store programs include hard disks, magnetic tapes, cassette tapes, optical discs, EEPROMs, and semiconductor memories such as flash ROMs. Furthermore, a recording medium is a non-temporary medium that allows a computer to read the program. The term "program" here refers not only to programs directly executable by the CPU, but also to source code programs, compressed programs, and encrypted programs. Includes, etc.

[0028] Figure 2 is a detailed diagram of a powder storage device according to an embodiment. The powder storage device 1 shown in Figure 2 inerts the inside of a silo container 100. The silo container 100 has tapered inlet 110 and outlet 120 portions. The silo container 100 is cylindrical, and powder 104 is stored inside it.

[0029] Multiple temperature sensors 102 are provided on the outer surface of the silo container 100. A temperature sensor 105 is also provided in the center of the silo container 100. The temperature inside the silo container 100 is measured by the temperature sensors 102 and 105, and when the temperature inside the silo container 100 exceeds a predetermined value, the inside of the silo container 100 is cooled. Note that the temperature sensors 102 are not necessarily required.

[0030] An input section 200 is provided on top of the silo container 100. Powder is fed from the input section 200 to the inlet 110. The rate at which the powder is fed from the input section 200 to the inlet 110 is adjustable.

[0031] The powder 104 is discharged from the outlet 120 of the silo container 100. An injection section 300 is provided on the circumferential surface of the silo container 100. The injection section 300 has a pipe 107 and a nozzle 103 attached to the pipe 107. The pipe 107 is connected to a control unit 400. The flow of gas or other substances within the pipe 107 is controlled by the control unit 400.

[0032] The control unit 400 includes, for example, a valve and a computer that controls the valve. The control unit 400 is connected to at least one of the following: a group of high-pressure vessels 610, a CE (cold evaporator) tank device 620, and a PSA (Pressure Swing Adsorption) device 630. Yes, they are.

[0033] The high-pressure vessel group 610 is composed of multiple cylinders 611. These cylinders 611 are filled with, for example, nitrogen gas. The nitrogen gas used when injecting nitrogen gas into the silo container 100 from the nozzle 103 is supplied from the cylinders 611. The control unit 400 and the high-pressure vessel group 610 are connected by piping 619.

[0034] The CE tank device 620 includes a tank 621 for storing liquid nitrogen and a regulator 622 that receives liquid nitrogen from the tank and vaporizes it. The control unit 400 and the CE tank device 620 are connected by piping 629.

[0035] The PSA device 630 is a pressure fluctuation adsorption device. By utilizing the differences in the adsorption characteristics of adsorbents for different gases, it continuously separates the target gas (nitrogen) by repeatedly alternating between pressurizing and depressurizing. As an adsorbent, for example, "Bellfine activated carbon," a high-performance MSC (Molecular Sieves Carbon) manufactured by Air Water Inc., can be used. The control unit 400 and the PSA device 630 are connected by piping 639.

[0036] As the device for supplying nitrogen gas to the control unit 400, the high-purity nitrogen gas generator "V1" (product name) manufactured by Air Water Inc. may be used. This device stably generates high-purity nitrogen gas through heat exchange utilizing the coldness of liquid nitrogen. In other words, a large amount of heat is removed when liquid nitrogen vaporizes. This heat is used to cool the air, thereby liquefying oxygen, carbon dioxide, etc. in the air, and the nitrogen remaining as a gas is used for a predetermined purpose. This enables a stable supply of nitrogen gas at low cost.

[0037] For a dust explosion to occur, the presence of flammable dust and an ignition source are necessary. Three requirements are necessary for an explosion: the presence of oxygen, the need for oxygen, and the ability to inject nitrogen gas or the like to reduce the risk of a dust explosion. This not only reduces the amount of oxygen, but also reduces the flammability of the flammable dust and prevents the generation of an ignition source (static electricity).

[0038] Figure 3 is a graph showing the relationship between the total volume of powder and the amount of gas injected. As shown in Figure 3, there is a correlation between the total volume of powder and the risk of dust explosion, with the risk of dust explosion increasing as the total volume of powder increases. This is presumed to be because as the total volume of powder increases, the number of times the powder particles come into contact with each other when the powder is introduced into the silo container 100 increases, generating static electricity between the powder particles, which triggers a dust explosion. Furthermore, the risk of dust explosion is higher when the powder is wood pellets than when the powder is grain. This is presumed to be because wood pellets have a lower moisture content than grain. The data related to the graph in Figure 3 is stored in the memory unit 500.

[0039] Data regarding the total volume of the powder can be measured when the powder, transported by ship or other means, is unloaded. This data is input into, for example, the memory unit 500. Based on the input data and the graph in Figure 3, the amount of gas or other substance to be injected into the silo container 100 is determined. Then, when the powder is introduced from the input unit 200 to the inlet 110, the gas or other substance is injected based on the determined injection amount.

[0040] Figure 4 is a graph showing the relationship between the moisture content of the powder and the amount of gas injected. As shown in Figure 4, there is a correlation between the moisture content of the powder and the risk of dust explosion. When the moisture content of the powder decreases, the energy required to burn the powder (activation energy) decreases, and therefore the risk of dust explosion increases. This is presumed to be because when the moisture content of the powder decreases, the powder burns more easily inside the silo container 100. The data related to the graph in Figure 4 is stored in the memory unit 500.

[0041] Data regarding the moisture content of the powder is obtained by extracting a portion of the powder before it is put into the silo container 100 and measuring its moisture content. The moisture content data is input into, for example, the storage unit 500. Based on the input data and the graph in Figure 4, the amount of gas or other substances to be injected into the silo container 100 is determined. Then, when the powder is put from the input unit 200 to the inlet 110, the gas or other substances are injected based on the determined injection amount.

[0042] Figure 5 is a graph showing the relationship between powder particle size and the amount of gas injected. As shown in Figure 5, there is a correlation between powder particle size and the risk of dust explosion, and the risk of dust explosion increases as the powder particle size decreases. This is presumed to be because when the powder particle size is small, the surface area in contact with oxygen is large, making the powder more easily combusted inside the silo container 100. The data related to the graph in Figure 5 is stored in the memory unit 500.

[0043] Data regarding the particle size of the powder is obtained by extracting a portion of the powder before it is put into the silo container 100 and measuring its particle size. The particle size can be measured, for example, according to JIS-Z-8825:2013. Furthermore, the particle size of individual particles can be determined by photographing the powder before it is put into the silo container and performing image analysis. The data regarding the particle size is input into, for example, the storage unit 500. Based on the input data and the graph in Figure 5, the amount of gas or other substance to be injected into the silo container 100 is determined. Then, when the powder is put from the input unit 200 to the inlet 110, the gas or other substance is injected according to the determined injection amount.

[0044] Figure 6 is a graph showing the relationship between humidity at the time of powder input and the amount of gas injected. As shown in Figure 6, there is a correlation between humidity at the time of powder input and the risk of dust explosion, and the risk of dust explosion increases when humidity at the time of powder input. This is because when humidity is low, moisture does not easily adhere to the surface of the powder, so the energy required to burn the powder is reduced, and the powder burns inside the silo container 100. It is presumed that this will make it cheaper. The data related to the graph in Figure 6 is stored in the memory unit 500.

[0045] Data regarding humidity at the time of powder input is obtained from the humidity announced by the Japan Meteorological Agency at the time before the powder is added to the silo container 100. Furthermore, a hygrometer may be installed inside the silo container 100, and the humidity may be measured using that hygrometer.

[0046] Figure 7 is a graph showing the relationship between the explosive limit concentration of a powder and the amount of gas injected. As shown in Figure 7, there is a correlation between the explosive limit concentration of a powder and the risk of dust explosion; the lower the explosive limit concentration of the powder, the higher the risk of dust explosion. This is because a low explosive limit concentration indicates that the powder is easily explosive at low concentrations. The explosive limit concentration is determined primarily by the type of powder, with particle size, moisture content, etc., also taken into consideration. When determining the explosive limit concentration, it may be determined solely by the type of powder delivered to the input unit 200, or it may be determined by considering both the type of powder and particle size. As shown in Figure 7, the explosive limit concentration of wood pellets is about 1 / 4 that of grains, indicating that wood pellets are easily explosive. The data related to the graph in Figure 7 is stored in the storage unit 500.

[0047] Figure 8 is a graph showing the relationship between the statistical minimum ignition energy of a powder and the amount of gas injected. As shown in Figure 8, there is a correlation between the minimum ignition energy of a powder and the risk of dust explosion; the lower the minimum ignition energy of the powder, the higher the risk of dust explosion. This is because a low minimum ignition energy indicates that dust explosions are easily triggered by small amounts of energy. The minimum ignition energy is determined primarily by the type of powder, with particle size, moisture content, etc., also considered. When determining the minimum ignition energy, it may be determined solely by the type of powder delivered to the input unit 200, or it may be determined by considering both the type of powder and particle size. As shown in Figure 8, the minimum ignition energy of wood pellets is about 1 / 64th of that of grains, indicating that wood pellets are prone to explosion. The data related to the graph in Figure 8 is stored in the memory unit 500.

[0048] Figure 9 is a graph showing the relationship between the critical oxygen concentration of a powder and the amount of gas injected. As shown in Figure 9, there is a correlation between the critical oxygen concentration of a powder and the risk of dust explosion; the risk of dust explosion increases as the critical oxygen concentration of the powder decreases. This is because a low critical oxygen concentration indicates that a dust explosion can occur at a low oxygen concentration. The critical oxygen concentration is determined primarily by the type of powder, with particle size, moisture content, etc., also taken into consideration. When determining the critical oxygen concentration, it may be determined solely by the type of powder delivered to the input unit 200, or it may be determined by considering both the type of powder and particle size. The data related to the graph in Figure 9 is stored in the storage unit 500.

[0049] The dust explosion prevention system in the powder storage device 1 is a dust explosion prevention system for the powder storage device 1 that implements a neural network using an information processing device, wherein the powder storage device 1 comprises a silo container 100 for storing powder and an injection unit 300 for injecting at least one selected from the group consisting of inert gas, ions, and mist into the silo container 100, and the dust explosion prevention system of the powder storage device 1 comprises an input layer and an output layer, wherein the input data of the input layer is set to at least one of a plurality of risk factors related to powder dust explosion when powder is put into the silo container 100, and the output layer The system comprises a neural network that uses force data to determine the probability of a dust explosion occurring in the silo container 100 in the future from the time the powder is introduced, a machine learning unit that trains the neural network using the actual values ​​of the input data and output data as training data, an estimation unit that inputs the input data with the current time as the reference time to the neural network trained by the machine learning unit and calculates an estimated future value based on the output data with the current time as the reference time, and a control unit 400 that determines the amount to be injected from the injection unit according to the estimated value of the estimation unit, and the risk factors include the type of powder, the total volume of the powder, and powder These factors include the water content of the material, the particle size of the powder, the humidity at the time of powder introduction, the explosive limit concentration of the powder, the statistically minimum ignition energy of the fragments, and the limit oxygen concentration of the powder.

[0050] Input and output data for machine learning are obtained through simulation. Various risk factor values ​​are varied and input into a commercially available simulator. The values ​​output by the simulation are then used as training data.

[0051] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described above, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of Symbols]

[0052] 1 Powder storage device, 100 Silo container, 102, 105 Temperature sensor, 103 Nozzle, 104 Powder, 107, 619, 629, 639 Piping, 110 Inlet, 120 Outlet, 200 Input section, 300 Injection section, 400 Control unit, 500 Memory unit, 610 High-pressure container group, 611 Cylinder, 620 CE tank device, 621 Tank, 622 Regulator, 630 PSA device.

Claims

[Claim 1] A silo container for storing powder, The silo container is equipped with an injection section for injecting at least one selected from the group consisting of inert gas, ions, and mist. The system further comprises a control unit that adjusts the injection amount of at least one selected from the group consisting of the inert gas, ions, and mist, and a storage unit that stores a function necessary for adjusting the injection amount. The control unit adjusts the injection amount according to the type of powder and the total volume of the powder. A powder storage device comprising: an injection section provided on the circumferential surface of the silo container, the injection section having a pipe and a nozzle attached to the pipe, the pipe being connected to the control unit, the flow of at least one selected from the group consisting of inert gas, ions, and mist within the pipe being controlled by the control unit, and a plurality of temperature sensors provided on the circumferential surface of the silo container.

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