Dissolution inhibitor dispensing device

Abstract

To provide an elution inhibitor charging device capable of maintaining smooth supply of an elution inhibitor into a boiler.SOLUTION: An elution inhibitor charging device 1 comprises charging piping 60 that feeds a boiler 100 burning coal with a granular or powdery elution inhibitor 2, and a cooling air supply part 70 that supplies cooling air F, flowing toward the boiler 100, to the charging piping 60. The cooling air supply part 70 supplies the cooling air F from at least one of the side of a tip part 621 positioned on the boiler 100 side of the charging piping 60 and the side of a base end part 611 on the opposite side of the boiler 100.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an elution inhibitor input device.

Background Art

[0002] Conventionally, an elution inhibitor input device for inputting a granular or powdery elution inhibitor into a boiler that burns coal is known. For example, Patent Document 1 describes this type of technology. Patent Document 1 describes a device including a silo that receives and stores limestone powder, a feeder provided at the bottom of the silo for quantitatively cutting out the limestone powder, and an air transport piping system that transports the limestone powder cut out from the feeder using compressed air as a transport medium.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when an elution inhibitor is sent into a boiler using an input pipe such as an air transport piping system as in the device described in Patent Document 1, if the inner peripheral surface of the tip of the input pipe deteriorates due to the heat in the boiler, roughening of the inner peripheral surface often occurs. Due to the roughening of the inner peripheral surface at the tip, the fluidity of the granular or powdery elution inhibitor decreases, and the elution inhibitor stays at the tip of the input pipe.

[0005] An object of the present invention is to provide an elution inhibitor input device that can maintain smooth supply of an elution inhibitor into a boiler.

Means for Solving the Problems

[0006] The present invention relates to an anti-leaching agent feeding device comprising an input pipe for feeding granular or powdery anti-leaching agent into a coal-burning boiler, and a cooling air supply unit for supplying cooling air flowing toward the boiler to the input pipe, wherein the cooling air supply unit supplies cooling air from at least one of the tip end of the input pipe located on the boiler side and the base end end on the opposite side of the boiler.

[0007] The cooling air supply unit may supply cooling air from at least the tip end of the input piping located on the boiler side.

[0008] At least the tip of the aforementioned input piping may be made of a heat-resistant material and may be located inside the boiler.

[0009] The system may further include a vibration mechanism that applies vibration to the input piping.

[0010] The input piping further comprises a funnel-shaped inlet into which an anti-elution agent can be introduced, a storage section for storing the anti-elution agent introduced from the inlet, an anti-aggregation mechanism for preventing aggregation of the anti-elution agents stored in the storage section, and a feeder connected to the lower part of the storage section for sending the anti-elution agent to the boiler side, wherein the input piping may also send the anti-elution agent sent from the feeder into the boiler. [Effects of the Invention]

[0011] According to the present invention, it is possible to maintain a smooth supply of the elution inhibitor into the boiler. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing a dissolution inhibitor feeding device according to one embodiment of the present invention and a part of a boiler into which the dissolution inhibitor is fed by the dissolution inhibitor feeding device. [Figure 2] This figure shows the tip end of the input piping of the dissolution inhibitor input device according to one embodiment of the present invention. [Figure 3]This is an enlarged schematic diagram of the tip of the input piping of a dissolution inhibitor injection device that does not have a cooling air supply unit or a vibration mechanism, showing the state in which the dissolution inhibitor is accumulating at the tip of the input piping. [Figure 4] This is an enlarged schematic diagram of the tip of the input piping of the elution inhibitor input device according to one embodiment of the present invention, showing how the elution inhibitor is smoothly introduced into the boiler. [Modes for carrying out the invention]

[0013] Preferred embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following embodiments.

[0014] The elution inhibitor injection device 1 according to one embodiment of the present invention is a device for introducing an elution inhibitor 2 into a boiler 100 in a thermal power generation facility that generates electricity by burning coal. Figure 1 is a schematic diagram showing the elution inhibitor injection device 1 and a part of the boiler 100 into which the elution inhibitor 2 is introduced by the elution inhibitor injection device 1. Figure 2 is a diagram showing the tip 621 side of the injection pipe 60 of the elution inhibitor injection device 1, which will be described later. In Figures 1 and 2, the vertical direction of the paper is defined as the vertical direction (up and down direction) Y, and the horizontal direction of the paper perpendicular to the vertical direction Y is defined as the horizontal direction X.

[0015] The boiler 100 burns coal supplied from a pulverizer (not shown) in its furnace 101. A leaching inhibitor 2 is also added to the boiler 100 by a leaching inhibitor injection device 1. As shown in Figure 1, the side wall 110 of the boiler 100 is provided with an opening 113 for inserting the tip 621 of the injection pipe 6 of the leaching inhibitor injection device 1 (described later), and a viewing window 120 that closes the opening 113. The operator can visually inspect the furnace 101 through the viewing window 120.

[0016] When coal is burned in boiler 100, exhaust gas is generated, along with coal ash such as clinker ash and fly ash. The coal ash produced by combustion contains trace amounts of harmful trace elements such as boron, fluorine, selenium, arsenic, and hexavalent chromium.

[0017] The elution inhibitor 2 is a granular or powdery agent that can suppress the elution of harmful trace elements contained in the coal ash generated by combustion by adding it to coal or coal ash. Examples of the elution inhibitor include calcium carbonate, calcium hydroxide, calcium oxide, etc.

[0018] Next, the elution inhibitor feeding device 1 according to this embodiment will be described while referring to FIGS. 1 and 2. The elution inhibitor feeding device 1 includes a hopper 10, an introduction pipe 20, a storage section 30, an anti-agglomeration mechanism 40, a feeder 50, a feeding pipe 60, a cooling air supply section 70, a vibration mechanism 80, and a control section 90.

[0019] The hopper 10 is generally in an inverted conical shape and has a funnel-shaped inlet 11 at its upper surface through which the elution inhibitor 2 can be introduced. An opening to which the introduction pipe 20 is connected is formed at the lower end of the inlet 11.

[0020] The introduction pipe 20 is a pipe that extends downward from the lower end of the inlet 11. The introduction pipe 20 is provided such that its lower end is located within the storage section 30. The elution inhibitor 2 introduced from the inlet 11 by an operator is supplied to the storage section 30 through the introduction pipe 20.

[0021] The storage section 30 is a tank for storing the elution inhibitor 2. The storage section 30 has a cylindrical section 31 formed in a cylindrical shape on the upper side, a conical section 32 formed in a hollow substantially conical shape on the lower side, and a discharge pipe 33 that extends downward from the lower end of the conical section 32 and discharges the elution inhibitor 2. A plurality of openings 321 to which a compressed air supply pipe 422 described later is connected are formed in the side wall of the conical section 32. The lower end of the discharge pipe 33 is connected to the feeder 50 in a communicable manner.

[0022] The anti-agglomeration mechanism 40 prevents the agglomeration of the elution inhibitors 2 stored in the storage section 30. The anti-agglomeration mechanism 40 includes a stirring device 41 and an air supply device 42.

[0023] The stirring device 41 is a device for stirring the elution inhibitor 2 stored in the storage section 30. The stirring device 41 has a shaft 411 with stirring blades 413 at its tip, and a motor 412 that rotates the shaft 411 around its axial direction. The stirring blades 413 of the shaft 411 are positioned on the discharge pipe 33 side of the conical section 32. When the shaft 411 rotates due to the drive of the motor 412, the stirring blades 413 rotate around the axial direction of the shaft 411. By efficiently stirring the elution inhibitor 2 from below the storage section 30 through the rotation of these stirring blades 413, aggregation of the elution inhibitors 2 can be prevented.

[0024] The air supply device 42 is a device that supplies compressed air into the storage section 30. The air supply device 42 comprises an air compressor 421 and compressed air supply piping 422. The air compressor 421 is a device that generates compressed air and supplies the generated compressed air into the storage section 30. The compressed air supply piping 422 is piping that forms a flow path for compressed air to circulate between the air compressor 421 and the storage section 30. The compressed air supply piping 422 has a main pipe 424 extending from the air compressor 421 toward the storage section 30, and a plurality of branch pipes 425 branching from the end of the main pipe 424 on the storage section 30 side. The main pipe 424 is provided with an on / off valve 423 that can open and close the flow path of compressed air. Each of the plurality of branch pipes 425 is connected to the opening 321 of the conical section 32 in the storage section 30, as shown in Figure 1. Specifically, the flow path in the compressed air supply pipe 422 and the inside of the storage section 30 are in communication through a plurality of openings 321. With this configuration, the compressed air generated by the air compressor 421 is sent through the compressed air supply pipe 422 to the inside of the conical section 32 of the storage section 30 through the plurality of openings 321. This allows the elution inhibitor 2 to be dispersed by the compressed air blown from the bottom of the storage section 30. Also, as shown in Figure 1, at least one of the plurality of openings 321 to which the compressed air supply pipe 422 is connected is positioned in the same position as the stirring blade 413 in the vertical direction Y. With this configuration, compressed air can be directly applied to the elution inhibitor 2 that is in contact with the rotating stirring blade 413, so that the aggregation of the elution inhibitor 2 can be prevented more reliably.

[0025] The feeder 50 is connected to the lower part of the storage section 30 and is a device that sends the elution inhibitor 2 to the boiler 100. Specifically, the feeder 50 extends horizontally in the X direction, its upper surface is connected to the lower end of the discharge pipe 33, and its tip is connected to the input pipe 60. The feeder 50 has a spiral screw 51 located inside and extending horizontally in the X direction, and a motor 52 that rotates the screw 51. When the screw 51 rotates due to the drive of the motor 52, the elution inhibitor 2 discharged from the discharge pipe 33 of the storage section 30 is sent out in the axial direction of the screw 51 and supplied to the input pipe 60.

[0026] The input pipe 60 is a pipe that delivers the elution inhibitor 2 into the boiler 100. The input pipe 60 is located on the feeder 50 side and has a vertical section 61 that extends downward in the vertical direction Y, and an inclined section 62 that extends diagonally downward from the lower end of the vertical section 61 toward the boiler 100 side.

[0027] A feeder 50 is connected to the vertical section 61 so as to communicate its interior with the inside of the feeder 50, and an on-off valve 64 is provided on its lower end. The on-off valve 64 is a valve that can be switched between an open state, which allows the elution inhibitor 2 to pass through the input pipe 60, and a closed state, which prevents the elution inhibitor 2 from passing through. Furthermore, an upstream cooling air supply unit 71, which will be described later, is connected to the upper end of the vertical section 61, i.e., the base end 611 located on the opposite side of the input pipe 60 from the boiler 100.

[0028] The inclined section 62 has its lower end, i.e., the tip 621 located on the boiler 100 side of the input pipe 60, positioned in the furnace 101 of the boiler 100. Specifically, a portion of the inclined section 62 on the tip 621 side is inserted into the boiler 101 from outside the roadway 102 through an opening 113 and a viewing window 120 provided in the side wall 110 of the boiler 100. A through-hole 121 is formed in the viewing window 120 through which the input pipe 60 is inserted. At least the inner circumferential surface of the through-hole 121 is formed of refractory material. Examples of refractory material include refractory bricks. The elution inhibitor 2 supplied from the feeder 50 passes through the input pipe 60 and is sent out into the furnace 101 of the boiler 100 through the opening 622 of the tip 621. When calcium carbonate or the like is mixed with coal and burned, the calcium lowers the ash melting point, and there is a risk that the molten coal ash will grow into a large mass (slugging / fouling) in the heat exchange section (not shown) of the boiler 100. On the other hand, by directly adding the leaching inhibitor 2 to the boiler 100 as in this embodiment, the risk of the above phenomenon occurring can be reduced. In addition, the amount of leaching inhibitor 2 added can be easily controlled.

[0029] The material of the tip 621 of the inclined section 62 is preferably a heat-resistant material. A heat-resistant material is a metal with a heat resistance temperature of 1000°C or higher, such as alloys, ceramics, and alumina. Examples of alloys include alloys containing Ni, Cr, Fe, Mo, W, etc. (for example, the Hastelloy® series manufactured by Haynes). In this embodiment, the material of the tip 621 of the inclined section 62 and the part of the boiler 100 that is on the furnace side 101 side of the inner wall 111 is a heat-resistant material, but the material of the entire input piping 60 may be a heat-resistant material, or the material of the input piping 60 up to the vicinity of the connection part with the downstream cooling air supply section 72 may be a heat-resistant material.

[0030] The cooling air supply unit 70 supplies cooling air F flowing toward the boiler 100 to the input pipe 60. The cooling air supply unit 70 comprises an upstream cooling air supply unit 71 and a downstream cooling air supply unit 72. The temperature of the cooling air F may be below room temperature, for example, 35°C or below.

[0031] The upstream cooling air supply unit 71 supplies cooling air F to the boiler 100 from the base end 611 side of the input pipe 60. The upstream cooling air supply unit 71 comprises an upstream cooling air generation unit 711 and an upstream cooling air supply pipe 712. The upstream cooling air generation unit 711 is a device that generates compressed cooling air F and supplies the generated cooling air F into the input pipe 60. The upstream cooling air supply pipe 712 is a pipe whose one end is connected to the upstream cooling air generation unit 711 and whose other end is connected to the base end 611 of the input pipe 60. A flow path is formed in the upstream cooling air supply pipe 712 through which the cooling air F flows between the upstream cooling air generation unit 711 and the input pipe 60. The upstream cooling air supply pipe 712 is also provided with an on / off valve 713 that can open and close the flow path of the cooling air. When the upstream cooling air generation unit 711 is driven and the on-off valve 713 is opened, cooling air F flows through the input pipe 60 from the base end 611 toward the boiler 100. This efficiently pushes the elution inhibitor 2 supplied from the feeder 50 toward the boiler 100 and suppresses the rise in temperature of the entire input pipe 60.

[0032] The downstream cooling air supply unit 72 supplies cooling air F to the boiler 100 from the tip end 621 side of the input pipe 60. In this specification, the tip end 621 side of the input pipe 60 refers to, for example, the area closer to the boiler 100 than the center of the inclined section 62 in the longitudinal direction, and the range from approximately 3.5 m from the outer wall 112 of the side wall 110 of the boiler 100 along the input pipe 60 toward the base end 611 to the tip end 621.

[0033] The downstream cooling air supply unit 72 comprises a downstream cooling air generation unit 721 and a downstream cooling air supply pipe 722. The downstream cooling air generation unit 721 is a device that generates cooling air F and supplies the generated cooling air F into the inclined section 62. The downstream cooling air supply pipe 722 is a pipe whose one end is connected to the downstream cooling air generation unit 721 and whose other end is connected to the tip 621 side of the input pipe 60. A flow path is formed in the downstream cooling air supply pipe 722 through which the cooling air F flows between the downstream cooling air generation unit 721 and the input pipe 60. The downstream cooling air supply pipe 722 is also provided with an on / off valve 723 that can open and close the flow path of the cooling air. In this embodiment, the distance from the downstream cooling air generation unit 721 to the opening 113 of the boiler 100 is approximately 50m to 100m.

[0034] As shown in Figure 2, in this embodiment, the distance d1 from the outer wall 112 of the side wall 110 of the boiler 100 to the connection point with the input pipe 60 in the downstream cooling air supply pipe 722 is 0.20m to 0.30m along the input pipe 60.

[0035] When the downstream cooling air generation unit 721 is driven and the on-off valve 723 is opened, cooling air F flows through the input pipe 60 from the tip end 621 towards the boiler 100. This efficiently pushes the elution inhibitor 2 towards the boiler 100 and suppresses the temperature rise of the inner circumferential surface 632 of the tip end 621 of the input pipe 60.

[0036] The vibration mechanism 80 is positioned on the outer circumferential surface 631 of the input pipe 60 and applies vibration to the input pipe 60. The vibration mechanism 80 comprises a plurality of vibrators 81 to 83. Vibrator 83 is positioned near the boundary between the vertical portion 61 and the inclined portion 62 on the outer circumferential surface 631. Vibrator 82 is positioned between the longitudinal center of the inclined portion 62 on the outer circumferential surface 631 and vibrator 73. Vibrator 81 is positioned on the tip portion 621 side of the outer circumferential surface 631. More specifically, vibrator 81 is positioned on the base portion 611 side of the connection portion with the downstream cooling air supply pipe 722 on the tip portion 621 side of the outer circumferential surface 631.

[0037] The transducer 81 is composed of transducers 811 and 812 positioned opposite each other across the input pipe 60. In this embodiment, transducer 811 is positioned on the upper outer surface 631, and transducer 812 is positioned on the lower outer surface 631. As shown in Figure 2, in this embodiment, the distance d2 from the outer wall 112 of the boiler 100 to transducer 811 is 0.35m to 0.45m along the input pipe 60. The distance d3 from the outer wall 112 of the boiler 100 to transducer 812 is 0.35m to 0.45m along the input pipe 60. By vibrating transducers 81 to 83, vibrations can be transmitted to the entire inner surface 632 of the inclined section 62, allowing the elution inhibitor 2 to be delivered into the boiler 100 more smoothly.

[0038] Here, the effects of the cooling air supply unit 70 and the vibration mechanism 80 will be explained with reference to Figures 3 and 4. Figure 3 is an enlarged schematic diagram of the tip 621 side of the input pipe 60 of the elution inhibitor input device without the cooling air supply unit 70 and the vibration mechanism 80, showing the state in which the elution inhibitor 2 is accumulating at the tip 621 of the input pipe 60. Figure 4 is an enlarged schematic diagram of the tip 621 side of the input pipe 60 of the elution inhibitor input device 1, showing how the elution inhibitor 2 is smoothly introduced into the boiler 100.

[0039] As shown in Figure 3, the tip 621 of the input pipe 60 is located inside the furnace 101 of the boiler 100, so its inner surface 632 deteriorates due to the heat inside the furnace 101, causing roughness R to occur. Due to this roughness R caused by thermal deterioration, the elution inhibitor 2 may not flow smoothly over the inner surface 632, and the opening 622 may become blocked.

[0040] In contrast, in the elution inhibitor feeding device 1 according to this embodiment, as shown in Figure 4, cooling air F is supplied from the cooling air supply unit 70 to the feeding pipe 60 toward the boiler 100, so that the temperature rise of the inner surface 632 of the tip 621 located inside the boiler 100 can be suppressed. As a result, deterioration of the inner surface 632 of the feeding pipe 60 is suppressed, and the formation of rough surface R is suppressed, so that the elution inhibitor 2 can be sent more smoothly into the furnace 101. In addition, since the vibration of the pair of vibrators 81 arranged on the tip 621 side is transmitted to the tip 621, even if rough surface R is formed on the inner surface 632 of the tip 621, the accumulation of the elution inhibitor 2 near the opening 622 can be prevented.

[0041] The control unit 90 is a processing unit composed of a processor and controls the drive of the elution inhibitor injection device 1. Specifically, the control unit 90 controls the drive of the motor 412 of the stirring device 41, the on-off valve 423 provided in the compressed air supply pipe 422 of the air supply device 42, the motor 52 of the feeder 50, the on-off valve 64, the upstream cooling air generation unit 711, the downstream cooling air generation unit 721, the on-off valves 713 and 723, the vibration mechanism 80, and the like.

[0042] The elution inhibitor dispensing device 1 according to this embodiment, as described above, provides the following effects.

[0043] The elution inhibitor injection device 1 according to this embodiment includes an injection pipe 60 for sending granular or powdered elution inhibitor 2 into the furnace 101 of a coal-burning boiler 100, and a cooling air supply unit 70 for supplying cooling air F flowing toward the boiler 100 to the injection pipe 60. The cooling air supply unit 70 supplies cooling air F from at least one of the tip end 621 side of the injection pipe 60 located toward the boiler 100 and the base end end 611 side opposite the boiler 100.

[0044] This allows cooling air F to flow towards the boiler 100 within the input pipe 60, thereby smoothly pushing the elution inhibitor 2 into the boiler 100 and suppressing the temperature rise of the inner circumferential surface 632 on the tip end 621 side. This suppresses deterioration of the inner circumferential surface 632 of the tip end 621, such as the occurrence of surface roughness R due to the heat inside the furnace 101 of the boiler 100, and thus maintains a smooth supply of the elution inhibitor 2 into the boiler 100.

[0045] Furthermore, in the elution inhibitor injection device 1 according to this embodiment, the cooling air supply unit 70 supplies cooling air F from at least the tip portion 621 located on the boiler 100 side of the injection pipe 60.

[0046] This allows for a more reliable supply of low-temperature cooling air F to the inner circumferential surface 632 of the tip 621 of the input pipe 60, thereby maintaining a smooth supply of the elution inhibitor 2.

[0047] Furthermore, in the elution inhibitor injection device 1 according to this embodiment, at least the tip portion 621 of the injection pipe 60 is made of a heat-resistant material and is located inside the boiler 100.

[0048] This makes it possible to suppress the deterioration of the tip portion 621 due to the heat inside the furnace 101 of the boiler 100.

[0049] Furthermore, the elution inhibitor injection device 1 according to this embodiment further includes a vibration mechanism 80 that applies vibration to the injection pipe 60.

[0050] This prevents the accumulation of the elution inhibitor 2 within the input pipe 60.

[0051] Furthermore, the elution inhibitor input device 1 according to this embodiment further comprises a funnel-shaped input port 11 into which the elution inhibitor 2 can be introduced, a storage section 30 for storing the elution inhibitor 2 introduced from the input port 11, an anti-aggregation mechanism 40 for preventing the elution inhibitor 2 stored in the storage section 30 from aggregating with each other, and a feeder 50 connected to the lower part of the storage section 30 for sending the elution inhibitor 2 to the boiler 100, and the input piping 60 sends the elution inhibitor 2 sent from the feeder 50 into the boiler 100.

[0052] As a result, the inlet 11 is funnel-shaped, making it easy to put in the elution inhibitor 2, and preventing the elution inhibitors 2 from agglomerating in the storage section 3. This also allows the elution inhibitor 2 discharged from the storage section 3 to be efficiently sent from the feeder 50 to the input pipe 60. Therefore, a large amount of elution inhibitor 2 can be smoothly supplied into the boiler 100.

[0053] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate.

[0054] In the above embodiment, the cooling air supply unit 70 included both an upstream cooling air supply unit 71 and a downstream cooling air supply unit 72, but it may also be configured to include either the upstream cooling air supply unit 71 or the downstream cooling air supply unit 72.

[0055] In the above embodiment, the input pipe 60 had a configuration having a vertical section 61 and an inclined section 62. However, it is also possible for the input pipe 60 not to be divided into a vertical section 61 and an inclined section 62, but rather the entire input pipe 60 to extend diagonally downward toward the boiler 100. [Explanation of Symbols]

[0056] 1. Dissolution inhibitor dispensing device 2. Dissolution inhibitors 60 Input piping 611 Proximal end 70 Cooling air supply unit 71 Upstream cooling air supply unit 72 Downstream cooling air supply unit 621 Tip 100 boilers F Cooling air

Claims

1. An input pipe for delivering granular or powdered elution inhibitor into a coal-burning boiler, A cooling air supply unit that supplies cooling air flowing toward the boiler to the input pipe, The system includes a vibration mechanism that applies vibration to the input piping, The cooling air supply unit includes a downstream cooling air supply unit that supplies cooling air from the tip end of the input piping located on the boiler side, The downstream cooling air supply unit is connected to the tip end of the input piping and has a downstream cooling air supply piping through which cooling air flows. The vibration mechanism has two vibrators positioned opposite each other across the input pipe, The two vibrators are located on the tip end side of the outer surface of the input pipe and are positioned on the base end side of the connection between the downstream cooling air supply pipe and the input pipe in the elution inhibitor input device.

2. The elution inhibitor injection device according to claim 1, wherein at least the tip of the injection pipe is made of a heat-resistant material and is located inside the boiler.

3. A funnel-shaped opening into which an anti-elution agent can be added, A storage section for storing the elution inhibitor introduced from the aforementioned inlet, An aggregation prevention mechanism for preventing aggregation of the elution inhibitors stored in the storage section, The storage section is further equipped with a feeder connected to the lower part of the storage section for supplying the elution inhibitor to the boiler side, The feeding pipe is used to feed the elution inhibitor sent from the feeder into the boiler, as described in claim 1 or 2 of the elution inhibitor feeding device.

4. The storage section comprises a cylindrical section formed on the upper side, a hollow conical section formed on the lower side, and a discharge pipe extending downward from the lower end of the conical section for discharging the elution inhibitor. The aforementioned coagulation prevention mechanism comprises an agitator in which agitating blades are positioned on the discharge pipe side of the conical portion, and an air supply device that supplies compressed air into the interior of the conical portion. The side wall of the conical portion has a plurality of openings, at least one of which is positioned in the same location as the stirring blade in the vertical direction. The elution inhibitor injection device according to claim 3, wherein the air supply device supplies compressed air from the plurality of openings to the interior of the conical portion via compressed air supply piping connected to the plurality of openings.

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