WO2019221009A1

WO2019221009A1 - Biomass bunker and boiler plant comprising same

Info

Publication number: WO2019221009A1
Application number: PCT/JP2019/018599
Authority: WO
Inventors: 洋輔大西; 光輝松▲崎▼; 祐樹近藤; 豊竹野; 浩明金本; 博司湯浅; 淳鹿島; 相澤　孝
Original assignee: 三菱日立パワーシステムズ株式会社
Priority date: 2018-05-17
Filing date: 2019-05-09
Publication date: 2019-11-21
Also published as: JP2021167674A

Abstract

A biomass bunker (31) comprises: a bunker (51) that stores biomass fuel; a humidity monitoring meter (52) that detects the humidity in the bunker (51); a two-fluid nozzle (53) that injects a mixed fluid of water and air; a water supply pipe (54) and an air supply pipe (55) that are connected to the two-fluid nozzle (53); a flow rate regulating valve (56) provided in the water supply pipe (54) and an on-off valve (57) provided in the air supply pipe (55); and a control panel (58) that controls switching of the flow rate regulating valve (56) and the on-off valve (57). The control panel (58) switches the flow rate regulating valve (56) and the on-off valve (57) from the closed state to the open state when the detected value from the humidity monitoring meter (52) drops below a set value that is set in the control panel (58).

Description

Biomass bunker and boiler plant equipped with the same

The present invention relates to a biomass bunker that stores biomass fuel and a boiler plant that burns biomass fuel.

In recent years, in thermal power plants, in consideration of economic efficiency and environmental problems, new construction and remodeling of plants using biomass fuel as an alternative fuel for pulverized coal or as a mixed combustion fuel with pulverized coal are being promoted. Woody biomass pellets are used as biomass fuel applied to thermal power plants because they are easy to handle. Woody biomass pellets are obtained by forming woody biomass into pellets. The woody biomass pellets are stored in a biomass bunker, conveyed from the biomass bunker to a vertical crusher, and crushed. Although “pulverization” is more appropriate as a term representing the size of the woody biomass pellets suitable for combustion, in the present specification, “pulverization” is used in accordance with the example of coal. The pulverized woody biomass pellets are supplied to a boiler device and burned.

∙ Biomass fuel has a large amount of volatile components, and thus tends to burn quickly if not properly managed. For this reason, the biomass bunker that stores the woody biomass pellets is required to be manageable so that the stored woody biomass pellets do not reach rapid combustion.

Therefore, Patent Document 1 includes a temperature detector for monitoring the temperature in the hopper in a pyrite hopper attached to the coal-fired boiler plant, and a spray water header for injecting spray water into the hopper. When the detected temperature becomes equal to or higher than the set temperature, there is known one that sprays spray water from the spray water header into the hopper (see Patent Document 1).

Patent Document 2 states that “in a vertical crushing apparatus in which a contracted flow area is formed between a housing and a mortar-shaped hopper, A flow rate adjusting member for adjusting the rising speed is provided (summary excerpt). "A vertical crusher capable of crushing both coal and biomass is disclosed. If the biomass bunker is also provided with a temperature detector and a spray water header similar to those of the pyrite hopper, an excessive temperature rise of the woody biomass pellets can be suppressed, and rapid combustion can be prevented. In addition, spraying water can suppress the generation of dust in the biomass bunker, which can reduce the mixture concentration of dust and air in highly flammable biomass fuel. From this point also, rapid combustion occurs in the biomass bunker. Can be suppressed.

Japanese Utility Model Publication No. 60-086742 JP 2012-24652 A

However, the woody biomass pellets stored in the biomass bunker are highly water-absorbing and have characteristics not found in coal that collapse when they get wet and become fine particles. It is inappropriate to install the spray water header as it is in the biomass bunker.

Describing in detail this point, woody biomass pellets applied to thermal power plants include those called black pellets and those called white pellets because of the appearance color. Black pellets are obtained by roasting biomass and semi-carbonizing it to bring it closer to the properties of coal. On the other hand, white pellets are obtained by solidifying a finely ground biomass chip into a cylindrical shape.

¡Black pellets have relatively high water resistance, so no special problem will occur even if spray water is sprayed in the bunker. In contrast, white pellets are highly water-absorbing and disintegrate into fine particles when wetted with water, making it easier to absorb water. If a large amount of spray water is injected in the bunker, the combustion efficiency is poor. In addition, the water swells to a large extent and becomes a compacted state, which tends to cause a problem that the evacuation from the bunker is deteriorated. In addition, since white pellets have high water absorption, they tend to adhere to the contact surfaces of the bunker and the transport equipment provided on the downstream side, and the problem of hindering transport tends to occur. Furthermore, white pellets are easily fermented when a large amount of water is absorbed, and volatilization of volatilization increases due to the heat of fermentation. Therefore, there is a concern that spraying spray water may easily cause rapid combustion.

Such a problem occurs not only when storing white pellets, but also when storing woody biomass chips such as thinned wood and offcuts.

The present invention has been made to solve such problems of the prior art, and its purpose is to reliably prevent rapid combustion of stored biomass fuel and to prevent deterioration of biomass fuel due to water absorption. It is to provide a possible biomass bunker and a boiler plant equipped with the same.

In order to achieve the above object, the present invention has the structure described in the claims. For example, the present invention includes a bunker main body for storing biomass fuel, a humidity monitor for detecting humidity in the bunker main body, a two-fluid nozzle for injecting a mixed fluid of water and air, and the two A water supply pipe and an air supply pipe connected to the fluid nozzle, a flow control valve provided in the water supply pipe, an on-off valve provided in the air supply pipe, and switching between the flow control valve and the open / close valve. A control panel that controls, when the control panel determines that the detected value of the humidity monitor is lower than a set value set in the control panel, the flow control valve and the on-off valve from the closed state It switches to an open state, The mixed fluid of water and air is injected into the said bunker from the said 2 fluid nozzle, It is characterized by the above-mentioned.

Since the present invention has the above-described configuration, it is possible to provide a biomass bunker and a boiler plant that can reliably prevent rapid combustion of stored biomass pellets and can prevent deterioration of biomass fuel due to water absorption. Problems, configurations, and effects other than those described above will become apparent from the description of the embodiments described below.

It is a block diagram of the biomass bunker which concerns on 1st Embodiment. It is a block diagram of the coal and biomass burning boiler plant which concerns on embodiment. It is a functional block diagram of a control panel concerning a 1st embodiment. It is a flowchart which shows the switching control procedure of the flow regulating valve and opening / closing valve which concerns on 1st Embodiment. It is a figure which shows the example which evaluated the influence of humidity. It is a block diagram of the biomass bunker which concerns on 2nd Embodiment. It is a functional block diagram of the control panel which concerns on 2nd Embodiment. It is a flowchart which shows the switching control procedure of the flow regulating valve and opening / closing valve which concerns on 2nd Embodiment. It is a timing chart which shows switching processing of a flow control valve and an on-off valve concerning a 2nd embodiment. It is a flowchart which shows the switching control procedure of the flow regulating valve and opening / closing valve which concerns on 3rd Embodiment. It is a timing chart which shows switching processing of a flow control valve and an on-off valve concerning a 3rd embodiment.

First, an embodiment of a boiler plant according to the present invention will be described with reference to the drawings. In the following, a coal / biomass-fired boiler plant will be described as an example. However, the gist of the present invention is not limited to this and can be applied to a biomass-fired boiler plant.

FIG. 2 is a configuration diagram of a coal / biomass-fired boiler plant according to the embodiment. As shown in FIG. 2, the coal / biomass-fired boiler plant 1 according to the embodiment includes a furnace 2 that burns coal and biomass fuel, a pulverized coal supply unit 3 that supplies pulverized coal to the furnace 2, and biomass in the furnace 2. It is mainly composed of a biomass fuel supply unit 4 that supplies fuel and an exhaust gas purification device 5 that purifies combustion exhaust gas generated in the furnace 2.

The furnace 2 includes a pulverized coal-burning burner 11 and a biomass-burning burner 12, and co-fires pulverized coal supplied from the pulverized coal supply unit 3 and biomass fuel supplied from the biomass fuel supply unit 4. It is configured as follows.

The pulverized coal supply unit 3 includes a raw coal bunker 21 that stores raw coal, a raw coal carry-in conveyor 22 that carries raw coal into a raw coal bunker 21 from a coal storage not shown, and raw coal supplied from the raw coal bunker 21. Is pulverized into a predetermined size to produce pulverized coal as fuel, and the pulverized coal generated by the first vertical pulverizer 23 is supplied to the pulverized coal-burning burner 11. And a coal supply pipe 24. The pulverized coal generated by the first vertical crushing device 23 is dried by the transfer gas 25 blown into the first vertical crushing device 23, and passes through the coal supply pipe 24 to burn the pulverized coal exclusively burner 11. To be supplied.

The biomass fuel supply unit 4 has a predetermined size of the biomass bunker 31 that stores the biomass fuel, the biomass carry-in conveyor 33 that carries the biomass fuel from the biomass silo 32 into the biomass bunker 31, and the biomass fuel that is supplied from the biomass bunker 31. A second vertical crusher 34 that generates a pulverized biomass fuel that is pulverized into fuel, and a biomass feed pipe that supplies the pulverized biomass fuel generated by the second vertical pulverizer 34 to the biomass-burning burner 12 35. The pulverized biomass fuel produced by the second vertical pulverizer 34 is dried by the transfer gas 36 blown into the second vertical pulverizer 34, and passes through the biomass feed pipe 35 to burn the biomass exclusively. 12 is supplied. As the second vertical crusher 34, a coal vertical crusher similar to the first vertical crusher 23 can be used.

When the biomass fuel is conveyed, static electricity may be generated due to friction with the conveyor belt of the biomass carry-in conveyor 33, and the biomass carry-in conveyor 33 may be charged. Therefore, a conductive material such as steel or conductive rubber is used as the material of the conveyor. In addition, there may be a static elimination device 50 (for example, an ionizer or a static elimination rod) that removes static electricity from the conveyance belt of the biomass carry-in conveyor 33 or the wood pellets conveyed by the conveyance belt. As biomass fuel, woody biomass pellets such as black pellets or white pellets and woody biomass chips such as thinned wood or offcuts can be used. Further, as the

transfer gases

25 and 36, combustion exhaust gas generated in the furnace 2 or a mixed gas of combustion exhaust gas and primary air can be used.

The exhaust gas purification device 5 includes a denitration device 41, an air preheater 42, and an electric dust collector 43. The combustion exhaust gas generated in the furnace 2 is purified through the denitration device 41, the air preheater 42, and the electric dust collector 43, and released from the chimney (not shown) to the atmosphere. The configuration of the exhaust gas purification device 5 is not limited to this, and for example, another device such as a wet desulfurization device may be added, or a bag filter may be provided instead of the electric dust collector 43.

<First Embodiment>
Next, a first embodiment of a biomass bunker according to the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a biomass bunker according to the first embodiment. As shown in FIG. 1, a biomass bunker 31 according to the first embodiment includes a bunker body 51 that stores biomass fuel, a humidity monitor 52 that detects humidity in the bunker body 51, and a mixed fluid of water and air. A plurality of (three in the example of FIG. 1) two-fluid nozzles 53 that inject into the bunker body 51, a water supply pipe 54 and an air supply pipe 55 connected to the two-fluid nozzle 53, and a water supply pipe 54. The on-off valve 57 provided on the provided flow control valve 56 and the air supply pipe 55 and the control panel 58 for controlling the switching of the flow control valve 56 and the on-off valve 57 are provided. In addition, although illustration is abbreviate | omitted, the biomass bunker 31 is earth | grounded as a treatment required for antistatic of the stored biomass powder.

The bunker body 51 has a hopper structure in which an upper part from a substantially central part is formed in a cylindrical shape and a lower part from the substantially central part is formed in an inverted conical shape. A biomass fuel inlet (not shown) is opened at the top of the bunker body 51, and a biomass fuel outlet (not shown) is opened at the bottom.

The humidity monitor 52 may be one that monitors the absolute humidity in the bunker body 51 or one that monitors the relative humidity in the bunker body 51. However, the humidity monitor 52 can more easily generate static electricity in the bunker body 51. It is more advantageous to monitor the relative humidity because it can be monitored directly.

The two-fluid nozzle 53 ejects fine water droplets according to the so-called spraying principle. When the two-fluid nozzle 53 is used, fine water droplets can be injected into the bunker main body 51 as compared with the case where the spray water header is used. Therefore, the bunker main body 51 is not submerged without immersing the biomass fuel stored in the bunker main body 51. Inside humidity can be adjusted.

The supply start and supply stop of the mixed fluid into the bunker main body 51 are performed by switching control of the flow rate adjusting valve 56 and the on-off valve 57 by a switching signal output from the control panel 58. When the control panel 58 determines that the detected value of the humidity monitor 52 is equal to or less than the set value set in the control panel 58, the flow control valve 56 and the on-off valve 57 are switched from the closed state to the open state, and the two-fluid nozzle 53 Further, a mixed fluid of water and air is injected into the bunker body 51. Further, when the control panel 58 determines that the detected value of the humidity monitor 52 exceeds the set value set in the control panel 58, the control panel 58 switches the flow control valve 56 and the on-off valve 57 from the open state to the closed state. The ejection of the mixed fluid from the fluid nozzle 53 is stopped.

FIG. 3 is a functional block diagram of the control panel according to the first embodiment. As shown in FIG. 3, the control panel 58 according to the embodiment includes a signal input unit 62, a signal output unit 63, a CPU (Central Processing Unit) 64, and a ROM (Read Only Memory) 65 connected to each other via a bus. And a computer having hardware resources such as a RAM (Random Access Memory) 66. The signal input unit 62 receives a detection signal from the humidity monitor 52 and an output signal from an input device 61 such as a keyboard input device or a touch panel input device. The signal output unit 63 is connected to a drive operation unit of the flow rate adjustment valve 56 and a drive operation unit of the on-off valve 57. The operator of the coal / biomass-fired boiler plant 1 operates the input device 61 to set the flow rate of the flow rate control valve 56 and the humidity threshold value for regulating the drive timing of the flow rate control valve 56 and the on-off valve 57. be able to.

The humidity threshold is set in the range of 30-40% relative humidity. When the relative humidity in the bunker body 51 falls below the range of 30 to 40%, the biomass fuel stored in the bunker body 51 is likely to be charged with static electricity, and rapid combustion occurs in the volatile components volatilized from the biomass fuel by discharge. This is because it becomes easier. The humidity threshold value is not limited to the above value, and can be set to an appropriate value in accordance with the operation of the coal / biomass-fired boiler plant 1.

The ROM 65 is a nonvolatile semiconductor memory that can retain programs and data even when the power is turned off. The ROM 65 stores a control program for the flow rate control valve 56 and the on-off valve 57 and a set flow rate and humidity threshold value of the flow rate control valve 56 input from the input device 61. The ROM 65 includes an SD memory card, a USB (Universal Serial Bus) memory, and the like.

The RAM 66 is a volatile semiconductor memory that temporarily stores programs and data.

The CPU 64 reads out the control program for the flow rate control valve 56 and the on-off valve 57 from the ROM 65, the set flow rate and the humidity threshold value of the flow rate control valve 56, and develops them on the RAM 66, and executes the control program for the flow rate control valve 56 and the on-off valve 57 . Thus, the CPU 64 functions as a control device that appropriately switches and controls the flow rate adjustment valve 56 and the on-off valve 57 according to the humidity in the bunker body 51.

Hereinafter, the switching control procedure of the flow rate control valve 56 and the on-off valve 57 according to the embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a switching control procedure of the flow rate control valve and the on-off valve according to the first embodiment.

The CPU 64 repeatedly fetches the detection value of the humidity monitor 52 into the RAM 66 (procedure S1). Further, each time the CPU 64 fetches the detection value of the humidity monitor 52 into the RAM 66, it determines whether or not the fetched detection value of the humidity monitor 52 falls below the humidity threshold value (set value) stored in the ROM 65 ( Procedure S2). If it is determined in step S2 that the detected value of the humidity monitor 52 is below the humidity threshold (set value) (Yes in step S2), the process proceeds to step S3, and the flow rate adjustment valve 56 and the on-off valve 57 are turned on. By switching from the closed state to the open state, a mixed fluid of water and air is injected into the bunker body 51. On the other hand, when it is determined in step S2 that the detected value of the humidity monitor 52 is equal to or higher than the humidity threshold (set value) (No in step S2), the process proceeds to step S4, and the flow rate control valve 56 and the on-off valve 57 is switched from the open state to the closed state, and the injection of the mixed fluid into the bunker body 51 is stopped. The injection of the mixed fluid can be performed before and after the biomass fuel is introduced into the bunker main body 51.

Thereby, the biomass bunker 31 according to the embodiment and the boiler plant 1 equipped with the biomass bunker 31 can maintain the relative humidity in the bunker main body 51 at a humidity at which static electricity is unlikely to be generated. Combustion can be prevented. Moreover, since the biomass bunker 31 and the boiler plant 1 equipped with the biomass bunker 31 according to the embodiment can impart appropriate moisture in the bunker body 51, generation of dust from the biomass fuel can be suppressed, and rapid mixing of dust mixed with air can be achieved. Combustion can be prevented.

Furthermore, since the biomass bunker 31 according to the embodiment and the boiler plant 1 including the same are injected with a mixed fluid of air and water into the bunker body 51, the bunker body 51 is different from the case where water is injected from the spray water header. It is possible to prevent the biomass fuel inside from becoming soaked. Therefore, according to the biomass bunker 31 and the boiler plant 1 including the same according to the embodiment, even when white pellets or woody biomass chips are used as the biomass fuel, the collapse or excessive expansion of the biomass fuel is prevented, and the bunker Ejectability from the main body 51 and transportability by transport equipment can be appropriately maintained. Moreover, since fermentation by the feed water of biomass fuel can be suppressed, volatilization of volatile matter can be suppressed, and the occurrence of rapid combustion can also be suppressed from this point.

Second Embodiment
The second embodiment is an embodiment in which the injection control process of the mixed fluid is switched between a state in which biomass fuel is input (loaded) into the bunker body 51 and a state in which the biomass fuel is stored but not input. 1st Embodiment pays attention only to the detected value of the humidity monitor 52, determines whether to inject or stop the fluid mixture of water and air, and does not pay attention to whether biomass fuel is thrown in or not. This is different from the second embodiment. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

Injection control of a mixed gas in an injection control process (corresponding to the first control process) in a state where biomass fuel is input and an injection control process (corresponding to a second control process) in a state where biomass fuel is not input The reason for changing is that the biomass fuel is more likely to be charged with static electricity than coal, and in particular, the friction between the biomass powders is more increased during charging, so that the charging property is further increased.

That is, in the example in which the charge amount and the powder resistivity of the biomass powder were measured, it was confirmed that the charge amount was 10 to 100 times larger than the coal powder, and the low powder efficiency was 10 ⁷ orders of magnitude larger. . At this time, referring to the static electricity safety guideline 2007 (Occupational Safety and Health Research Institute), the risk level of charging can be evaluated as “medium”.

In addition, the energy required for the biomass powder to ignite is several mJ to several tens of mJ, which may be ignited with an energy level of static electricity. On the other hand, it was confirmed that coal powder does not ignite without a relatively large energy of several hundred mJ.

As mentioned above, despite the fact that biomass powder is easily charged with static electricity, the energy required for ignition is small, so it is necessary to take some safety measures. Therefore, in this embodiment, in order to prevent cone discharge (discharge energy: several tens of mJ) that is generated when the biomass bunker is input as an ignition source, water injection control processing is performed when the biomass fuel is input and when it is not. Switch.

An example of evaluating the influence of the humidity is shown in FIG. The device is a device that can measure the potential of a charged object in accordance with JIS C61340-2-1: 2006, and the temperature and humidity can be controlled to be constant in an environmental test machine.

It was confirmed that the potential difference V / V0 when the initial potential was V0 and the potential after a certain time was V decreased with time. It was found that the higher the humidity, the faster it decreases. For this reason, static electricity is discharged quickly at high humidity such as in summer, so the risk of ignition due to static electricity is small. However, when the humidity in winter is low, the potential drops slowly, so increasing the humidity causes static electricity. It is thought that the ignition risk can be reduced.

FIG. 6 is a configuration diagram of the biomass bunker according to the second embodiment. As shown in FIG. 6, the biomass bunker 31 a according to the second embodiment further includes a fuel gauge 81 that measures the storage amount in the bunker body 51.

FIG. 7 is a functional block diagram of the control panel according to the second embodiment. As shown in FIG. 7, the detection signal of the fuel gauge 81 is input to the control panel 58.

Further, a conveyor ON / OFF signal is input to the control panel 58 from a conveyor activation switch 82 that switches activation / deactivation of the biomass carry-in conveyor 33.

Control board 58 further includes a timer 83. And the injection time of the mixed gas of water and air is measured, and if it becomes more than predetermined time, injection will be stopped. The predetermined time here means, for example, that when the input biomass pellets uniformly absorb moisture, the amount of water is such that the increase in the amount of moisture allowed from the viewpoint of adhesion to the wall surface and the collapse of the pellets is less than 0.1%. And determined based on the injection amount per unit time. Further, for example, it may set a time for humidifying the volume V m ³ of biomass bunker to the target humidity. Here, the target humidity is set in the bunker when the design minimum absolute humidity x kg-w / kg-air, target absolute humidity y kg-w / kg-air, air density ρ kg / m ³ , and correction coefficient a are set. The amount of water required for this is W = a × V × ρ × (y−x), and the injection time is determined by the injection amount per unit time.

FIG. 8 is a flowchart showing a switching control procedure of the flow rate control valve and the on-off valve according to the second embodiment. FIG. 9 is a timing chart showing a switching process between the flow rate control valve and the on-off valve according to the second embodiment.

In FIG. 8, the process of transition from S10 OFF to S11 and S12 corresponds to a first control process performed in a state where biomass fuel is not input. Further, the process of transition from ON of S10 to S1 corresponds to a second control process that is performed while the biomass fuel is being charged.

When the biomass carry-in conveyor 33 is not activated, that is, when the conveyor OFF signal is input to the control panel 58 (S10 / OFF; T0 in FIG. 9), the fuel gauge is input to the control panel 58. The detection value 82 is input (S11). When the detected value (remaining amount) indicated by the fuel gauge 82 exceeds a predetermined remaining amount threshold value (S12 / No), it is predicted that the biomass carry-in conveyor 33 will not be activated most recently, so the procedure returns to step S10 and mixing. Waiting without ejecting fluid (T0 to T1 in FIG. 9).

When the detected value (remaining amount) indicated by the fuel gauge 82 becomes equal to or less than a predetermined remaining amount threshold value (S12 / Yes; T1 in FIG. 9), the biomass carry-in conveyor 33 has not yet started, but the bunker main body 51 It is predicted that the biomass carry-in conveyor 33 will start soon in order to input the biomass fuel. Then, it progresses to procedure S1 and the detected value of a humidity monitor is input into the control panel 58 (S1).

In this embodiment, the monitoring process of the injection duration using the timer 83 is added to the mixed fluid injection control process in the first embodiment. That is, when the detected value of the humidity monitor is equal to or lower than the lower limit value of the relative humidity target range in step S2 (S2 / Yes), the timer 83 is turned on (S51) and measurement of the injection duration time is started. If the injection duration is less than the predetermined time (S52 / Yes), the mixed fluid is injected into the bunker (S3).

Thus, prior to the start of the biomass carry-in conveyor 33 (T1 to T2 in FIG. 9), the mixed fluid can be injected to increase the relative humidity. Since cone discharge may occur when biomass fuel is input to the bunker main body 51, the bunker humidity is temporarily increased before the bunker is input. If a large amount of water is used, the biomass pellets may get wet and the shape may collapse. Therefore, in step S51, the elapsed time is measured, and when the predetermined time or more is reached (S52 / No), the mixed fluid is injected. Stop (S4) and turn off the timer 83 (S53). In order to prevent the necessary wetting of the bimus pellets, the above-described method was adopted because a large amount of water cannot be used.

Thereafter, when a conveyor ON signal is input to the control panel 58 (S10 / ON, T2 in FIG. 9), the processing from S1 is executed as described above.

When the conveyor ON signal is input (S10 / ON, T2 in FIG. 9) and the humidity is increased, the detected value of relative humidity reaches the target upper limit value (S2 / No, S21 / Yes; T3 in FIG. 9). Since sufficient humidity is secured even if the carry-in conveyor 33 is activated, the injection of the mixed fluid is temporarily stopped (S4).

Then, when the biomass carry-in conveyor 33 stops, a conveyor OFF signal is input (S10 / OFF; T4 in FIG. 9).

The biomass fuel in the bunker main body 51 is carried out and the remaining amount decreases. If the biomass carry-in conveyor 33 is activated again and a conveyor ON signal is input (S10 / ON) and the detected value of the humidity monitor at that time is equal to or lower than the lower limit (S2 / Yes; T5 in FIG. 9), the mixing is performed again. Restart fluid injection.

According to the second embodiment, before the biomass carry-in conveyor 33 is turned on, the injection of the mixed fluid can be started in order to increase the relative humidity to the target range, and the occurrence of cone discharge can be suppressed in advance. .

<Third Embodiment>
The third embodiment is a mode in which the mixed fluid is forcibly jetted while the biomass carry-in conveyor 33 is activated. This embodiment is an embodiment in which the conveyor ON / OFF signal is handled as a higher order command.

When the control panel 58 receives the input of the conveyor ON signal (S61 / Yes; T11 in FIG. 11), it injects the mixed fluid into the bunker (S3).

When the control panel 58 receives the input of the conveyor OFF signal (S62 / Yes; T12 in FIG. 11), the timer 83 is started and measurement of elapsed time is started (S63).

The control panel 58 continues to inject the mixed gas until the elapsed time reaches the stop margin time ΔT (T13-T12) (S64 / No).

When the elapsed time reaches the stop margin time (S64 / Yes; T13 in FIG. 11), the control panel 58 stops the injection of the mixed gas (S4) and stops the timer 83 (S65).

According to the third embodiment, the mixed fluid is forcibly injected while the biomass carry-in conveyor 33 is activated, and the mixed fluid is injected until the biomass fuel settles immediately after the stop, so that charging can be suppressed. In the third embodiment, while the conveyor OFF signal is being input, the injection of the mixed fluid is stopped after the stop margin time has elapsed. However, the detected value of the humidity monitor 52 is the target value even after the stop margin time has elapsed. When it is below the lower limit of the range, the mixed fluid may be ejected. In other words, the first to third embodiments may be combined as appropriate.

Each of the above embodiments does not limit the scope of the present invention, and changes are made to the components of the invention described in the above embodiments without departing from the spirit of the present invention, and are described in the above embodiments. What replaced the component of this invention with the well-known component is also contained. For example, in the above-described embodiment, only one humidity monitor 52 is installed in the bunker main body 51, but a plurality of humidity monitors 52 may be installed. When a plurality of humidity monitoring meters 52 are installed, the humidity distribution in the bunker body 51 can be detected, so that rapid combustion can be prevented more reliably.

DESCRIPTION OF SYMBOLS 1 ... Coal / biomass fired boiler plant, 2 ... Furnace, 3 ... Pulverized coal supply part, 4 ... Biomass fuel supply part, 5 ... Exhaust gas purification device, 11 ... Pulverized coal burner, 12 ... Biomass burner, 21 ... Raw coal Bunker, 22 ... Raw coal carry-in conveyor, 23 ... First vertical crusher, 24 ... Coal feed pipe, 25 ... Gas for conveyance, 31, 31a ... Biomass bunker, 32 ... Biomass silo, 33 ... Biomass carry-in conveyor, 34 DESCRIPTION OF SYMBOLS 2nd vertical crushing apparatus, 35 ... Biomass feed pipe, 36 ... Gas for conveyance, 41 ... Denitration apparatus, 42 ... Air preheater, 43 ... Electric dust collector, 51 ... Bunker main body, 52 ... Humidity monitor, 53 ... Two-fluid nozzle, 54 ... Water supply pipe, 55 ... Air supply pipe, 56 ... Flow control valve, 57 ... On-off valve, 58 ... Control panel, 81 ... Fuel gauge, 82 ... Conveyor start switch.

Claims

A bunker body for storing biomass fuel, a humidity monitor for detecting humidity in the bunker body, a two-fluid nozzle for injecting a mixed fluid of water and air, a water supply pipe and air connected to the two-fluid nozzle A supply pipe, a flow control valve provided in the water supply pipe and an open / close valve provided in the air supply pipe, and a control panel for controlling switching of the flow control valve and the open / close valve,
When the control panel determines that the detected value of the humidity monitor is lower than a set value set in the control panel, the flow control valve and the on-off valve are switched from a closed state to an open state, and the two fluids A biomass bunker characterized by injecting a mixed fluid of water and air into the bunker body from a nozzle.
In the biomass bunker according to claim 1,
The humidity monitor detects relative humidity in the bunker body, and the control panel determines that the relative humidity in the bunker body is below the set value set in a range of 30 to 40%. Then, the on-off valve and the flow rate control valve are switched from a closed state to an open state, and a mixed fluid of water and air is injected into the bunker body.
In the biomass bunker according to claim 1,
The biomass bunker, wherein the two-fluid nozzle is installed at an upper part of the bunker body and injects a mixed fluid of water and air toward the lower side of the bunker body.
A furnace, and a biomass bunker for storing biomass fuel supplied to the furnace,
The biomass bunker is connected to the bunker main body for storing biomass fuel, a humidity monitor for detecting humidity in the bunker main body, a two-fluid nozzle for injecting a mixed fluid of water and air, and the two-fluid nozzle. A water supply pipe and an air supply pipe; a flow control valve provided in the water supply pipe; an open / close valve provided in the air supply pipe; a control panel for controlling switching of the flow control valve and the open / close valve; With
When the control panel determines that the detected value of the humidity monitor is lower than a set value set in the control panel, the flow control valve and the on-off valve are switched from a closed state to an open state, and the two fluids A boiler plant, wherein a mixed fluid of water and air is jetted from a nozzle into the bunker body.
A bunker body for storing biomass fuel, a biomass carry-in conveyor for carrying the biomass fuel into the bunker, a humidity monitor for detecting humidity in the bunker body, and a two-fluid nozzle for injecting a mixed fluid of water and air A water supply pipe and an air supply pipe connected to the two-fluid nozzle, a flow control valve provided in the water supply pipe, an on-off valve provided in the air supply pipe, the flow control valve and the on-off valve A control panel for controlling the switching of
The control panel receives an input of a conveyor ON signal indicating that the biomass carry-in conveyor is started and a conveyor OFF signal indicating that the biomass carry-in conveyor is stopped, and the biomass fuel is input to the bunker main body. A first control process performed in between and a second control process different from the first control process, wherein the biomass fuel is stored in the bunker body but is not put in 2 control processing,
When the input of the conveyor ON signal is received, as the first control process, the flow control valve and the on-off valve are switched from a closed state to an open state, and water and air are introduced into the bunker body from the two-fluid nozzle. Control process for injecting a mixed fluid of
When receiving the input of the conveyor OFF signal, as the second control process, it is determined whether the detected value of the humidity monitor is equal to or less than a set value set in the control panel, and the detected value is set to the setting When the flow rate control valve and the on-off valve are switched from a closed state to an open state when the value is less than or equal to the value, a control process for injecting a mixed fluid of water and air into the bunker body from the two-fluid nozzle is executed. A featured biomass bunker.
In the biomass bunker according to claim 5,
The biomass bunker further comprises a fuel gauge for detecting the remaining amount of the biomass fuel stored in the bunker body,
The control panel receives an input of a detection value of the fuel gauge,
When the conveyor OFF signal is input and the detected value of the fuel gauge is equal to or less than a predetermined remaining amount threshold value, the flow control valve and the on-off valve are closed from the closed state as the second control process. A biomass bunker characterized by further performing a control process of switching to an open state and injecting a mixed fluid of water and air into the bunker body from the two-fluid nozzle.
In the biomass bunker according to claim 5,
As the first control process, the control panel switches the flow rate adjustment valve and the on-off valve from a closed state to an open state while the conveyor ON signal is being input, and the bunker from the two-fluid nozzle. Control that switches the flow rate control valve and the on-off valve from the open state to the closed state after a predetermined stop margin time has elapsed since the mixed fluid of water and air was injected into the body and the conveyor OFF signal was input. Biomass bunker characterized by executing processing.
A furnace, and a biomass bunker for storing biomass fuel supplied to the furnace,
The biomass bunker includes a bunker body that stores biomass fuel, a biomass carry-in conveyor that transports the biomass fuel, a humidity monitor that detects humidity in the bunker body, and two fluids that inject a mixed fluid of water and air A nozzle, a water supply pipe and an air supply pipe connected to the two-fluid nozzle, a flow control valve provided in the water supply pipe, an on-off valve provided in the air supply pipe, the flow control valve and the A control panel for controlling switching of the on-off valve,
The control panel receives an input of a conveyor ON signal indicating that the biomass carry-in conveyor is started and a conveyor OFF signal indicating that the biomass carry-in conveyor is stopped, and the biomass fuel is input to the bunker main body. A first control process performed in between and a second control process different from the first control process, the second control process performed while the biomass fuel is not charged in the bunker body, Run
When the input of the conveyor ON signal is received, as the first control process, the flow control valve and the on-off valve are switched from a closed state to an open state, and water and air are introduced into the bunker body from the two-fluid nozzle. Control process for injecting a mixed fluid of
When the input of the conveyor OFF signal is received, as the second control process, when it is determined that the detected value of the humidity monitor is lower than a set value set in the control panel, the flow control valve and the on-off valve The boiler plant is characterized in that a control process is performed in which a mixed fluid of water and air is injected into the bunker body from the two-fluid nozzle by switching from a closed state to an open state.