Monitoring device and monitoring method for storage tanks

Abstract

This ensures that spontaneous combustion of solid fuel stored in the storage tank is reliably suppressed. [Solution] A monitoring device 1 for a storage tank 3 in which solid fuel 2 is stored, comprising: a string-like member 4 suspended from the top of the storage tank 3 toward the center of the solid fuel 2; a plurality of temperature detection units 5 provided at intervals along the longitudinal direction of the string-like member 4 and embedded in the solid fuel 2 together with the string-like member 4; a plurality of inert gas supply units 6 provided at intervals along the longitudinal direction of the string-like member 4 and embedded in the solid fuel 2 together with the string-like member 4; an opening / closing mechanism 12 provided in each inert gas supply unit 6; an inert gas flow passage 10 provided along the longitudinal direction inside the string-like member 4 for circulating inert gas to each inert gas supply unit 6; and a control unit 7 that controls the opening and closing operation of the opening / closing mechanism 12 so that inert gas is supplied to the solid fuel 2 from the corresponding inert gas supply unit 6 based on temperature information detected by at least one temperature detection unit 5.

Description

Technical Field

[0001] The present invention relates to a monitoring device and a monitoring method for a storage tank storing solid fuel, and more particularly to fire prevention of the storage tank.

Background Art

[0002] In a storage tank storing solid fuel, spontaneous combustion may occur due to abnormal heat generation of the solid fuel caused by oxidation, fermentation, etc.

[0003] Therefore, for example, Patent Document 1 discloses a monitoring device for suppressing spontaneous combustion of such a storage tank.

[0004] Specifically, the monitoring device disclosed in the same document measures the coal temperature by temperature detection means suspended vertically in the central part of the coal storage tank, and when the coal temperature exceeds the set temperature, an inert gas is supplied into the coal storage tank by inert gas purge means.

[0005] The temperature detection means is arranged at the center of the coal stored in the coal storage tank. On the other hand, the inert gas purge means supplies an inert gas into the coal storage tank through a pipe connected to the bottom of the coal storage tank.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] When the thermal conductivity of a solid fuel is low, the center of the solid fuel does not dissipate heat easily and tends to become adiabatic. Therefore, abnormal heat generation of the solid fuel is likely to occur in the center of the solid fuel. However, the center of the solid fuel tends to become compacted due to the weight of the solid fuel itself. Therefore, as disclosed in Patent Document 1, when an inert gas is supplied from the bottom of the storage tank, even if abnormal heat generation of the solid fuel is detected, it is difficult to efficiently supply the inert gas to the center of the solid fuel that has become compacted. As a result, there is a risk that spontaneous combustion of the solid fuel cannot be reliably suppressed.

[0008] The present invention aims to reliably suppress the spontaneous combustion of solid fuel stored in a storage tank. [Means for solving the problem]

[0009] (1) The present invention, devised to solve the above problems, is a monitoring device for a storage tank in which solid fuel is stored, comprising: a string-like member suspended from the top of the storage tank toward the center of the solid fuel; a plurality of temperature detection units provided at intervals along the longitudinal direction of the string-like member and embedded in the solid fuel together with the string-like member; a plurality of inert gas supply units provided at intervals along the longitudinal direction of the string-like member and embedded in the solid fuel together with the string-like member; an opening and closing mechanism provided in each inert gas supply unit; an inert gas flow passage provided along the longitudinal direction inside the string-like member for circulating inert gas to each inert gas supply unit; and a control unit that controls the opening and closing operation of the opening and closing mechanism so that inert gas is supplied into the solid fuel from the corresponding inert gas supply unit based on temperature information detected by the temperature detection unit.

[0010] In this way, multiple temperature detection units and multiple inert gas supply units are provided on the string-like member. Therefore, when the string-like member is suspended from the top of the storage tank toward the center of the solid fuel, at least one temperature detection unit and inert gas supply unit can be positioned at the center of the solid fuel, even if the amount (height) of solid fuel in the storage tank fluctuates. As a result, the temperature detection unit can detect the temperature information of the center of the solid fuel. Furthermore, if abnormal heat generation is detected at the center of the solid fuel based on the temperature information from the temperature detection unit, the opening and closing mechanism can be opened to directly supply inert gas from the inert gas supply unit to the center of the solid fuel. Thus, spontaneous combustion of the solid fuel can be reliably suppressed. In addition, since the inert gas supply unit can be closed by the opening and closing mechanism when inert gas is not being supplied, it is also possible to prevent solid fuel from entering and blocking the inert gas supply unit or inert gas flow passage.

[0011] (2) In the configuration of (1) above, it is preferable to include a position detection unit that transmits position information of the temperature detection unit to the control unit.

[0012] In this way, it is possible to accurately determine which location within the solid fuel the temperature information detected by the temperature detection unit reflects.

[0013] (3) In the configuration of (2) above, the control unit controls the opening and closing operation of the opening and closing mechanism so that when the temperature information detected by the temperature detection unit exceeds a set threshold, inert gas is supplied from the corresponding inert gas supply unit, and it is preferable that the set threshold is adjusted based on position information.

[0014] In this way, even if the temperature detection unit is positioned away from the desired location, the set threshold can be adjusted to take that positional shift into account.

[0015] (4) In any of the configurations (1) to (3) above, a combustible gas detection unit is provided on the string-like member and embedded in the solid fuel together with the string-like member, and the control unit controls the opening and closing operation of the opening and closing mechanism so that an inert gas is supplied from the corresponding inert gas supply unit based on the temperature information detected by the temperature detection unit and the combustible gas information detected by the combustible gas detection unit.

[0016] When solid fuels generate heat, they often produce flammable gases such as methane and CO. Therefore, by detecting flammable gases using a flammable gas detection unit in addition to temperature information, abnormal heat generation within the solid fuel can be detected more accurately.

[0017] (5) In any of the configurations (1) to (4) above, it is preferable that the solid fuel is a biomass fuel.

[0018] Biomass fuels have low thermal conductivity, making them prone to abnormal heat generation in the center of the solid fuel. Therefore, the present invention, which can reliably detect abnormal heat generation in the center of the solid fuel and directly supply an inert gas to the center of the solid fuel, is particularly useful.

[0019] (6) The present invention, devised to solve the above problems, is a method for monitoring a storage tank in which solid fuel is stored, characterized in that a string-like member is suspended from the top of the storage tank toward the center of the solid fuel, a plurality of temperature detection units are provided at intervals in the longitudinal direction on the portion of the string-like member that is embedded in the solid fuel, a plurality of inert gas supply units are provided at intervals in the longitudinal direction on the portion of the string-like member that is embedded in the solid fuel, an opening and closing mechanism is provided for each inert gas supply unit, an inert gas flow passage is provided inside the string-like member along the longitudinal direction to allow inert gas to flow to each inert gas supply unit, and the opening and closing operation of the opening and closing mechanism is controlled so that inert gas is supplied from the corresponding inert gas supply unit based on temperature information detected by the temperature detection unit.

[0020] In this way, the same effects and benefits as those of the corresponding configuration already described can be enjoyed.

[0021] (7) In the configuration of (6) above, it is preferable that the string-shaped member is embedded in the solid fuel with slack.

[0022] By doing so, it is possible to suppress excessive tension from acting on the string-shaped member due to the weight of the solid fuel, and thus it is possible to suppress damage to the string-shaped member and its support member.

Effect of the Invention

[0023] According to the present invention, spontaneous ignition of the solid fuel stored in the storage tank can be reliably suppressed.

Brief Description of the Drawings

[0024] [Figure 1] It is a side view showing a monitoring device for a storage tank according to an embodiment of the present invention. [Figure 2] It is a front view of the string-shaped member. [Figure 3] It is a cross-sectional view taken along the line A-A of FIG. 2.

Mode for Carrying Out the Invention

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0026] As shown in FIG. 1, the monitoring device 1 according to the present embodiment is a device that monitors a storage tank 3 in which solid fuel 2 is stored, and functions as a fire prevention device for the storage tank 3. <00-00106>

[0027] The storage tank 3 is a container having an upper wall portion 3a, a bottom wall portion 3b, and a side wall portion 3c. An inlet 3a1 for charging the solid fuel 2 from the P direction is provided in the upper wall portion 3a. A discharge port 3b1 for discharging the solid fuel 2 in the Q direction is provided in the bottom wall portion 3b.

[0028] Solid fuel 2 is a biomass fuel such as wood pellets. Solid fuel 2 may also be a fossil fuel such as coal. The central X of the solid fuel 2 stored in the storage tank 3 can become a hot spot where abnormal heat generation occurs due to oxidation or fermentation of the solid fuel 2. In particular, when solid fuel 2 is a biomass fuel, the thermal conductivity of solid fuel 2 (e.g., 0.18 W / m / K to 0.24 W / m / K) is low, and the central X of solid fuel 2 is prone to becoming a hot spot. Here, the hot spot tends to form at a height of approximately H / 2, where the storage height of solid fuel 2 is H, and the most adiabatic state is likely to occur. Therefore, it is important to detect the temperature of solid fuel 2 in the region including a height of approximately H / 2.

[0029] The monitoring device 1 mainly comprises a string-like member 4, a temperature detection unit 5, an inert gas supply unit 6, and a control unit 7.

[0030] The string-like member 4 is made of, for example, a flexible wire rope. The string-like member 4 includes a portion located outside the storage tank 3 and a portion located inside the storage tank 3. The base end of the string-like member 4 is included in the portion located outside the storage tank 3, and the tip of the string-like member 4 is included in the portion located inside the storage tank 3. The base end of the string-like member 4 is supported by a winding device 8. The string-like member 4, supported by the winding device 8, is guided into the storage tank 3 from the inlet 3a1 of the storage tank 3 via a pulley 9. The string-like member 4, guided into the storage tank 3, is suspended from the inlet 3a1 of the storage tank 3 toward the center X of the solid fuel 2. The tip of the string-like member 4 is embedded in the solid fuel 2 stored in the storage tank 3. In this state, the tip of the string-like member 4 is located in the portion of the solid fuel 2 that includes the center X. In this embodiment, the tip of the string-like member 4 is located in the solid fuel 2 with slack. In other words, the tip of the string-like member 4 has a meandering portion within the solid fuel 2, rather than extending straight in the vertical direction. This prevents excessive tension from acting on the string-like member 4 due to the weight of the solid fuel 2, thereby preventing damage to the string-like member 4 and its support (winding device 8, pulley 9, etc.). The slack in the string-like member 4 (length of the string-like member 4) is adjusted by the winding device 8 when the solid fuel 2 is introduced from the input port 3a1.

[0031] The temperature detection unit 5 is a sensor that detects temperature information (temperature or information corresponding to temperature) of the solid fuel 2. The temperature detection unit 5 is provided at the tip of the string-like member 4 and is embedded in the solid fuel 2 together with the string-like member 4. Multiple temperature detection units 5 are provided at intervals (for example, 2 to 3 m apart) along the longitudinal direction of the string-like member 4. By providing multiple temperature detection units 5 in this way, at least one temperature detection unit 5 is positioned in the central part X of the solid fuel 2 that could become a hot spot.

[0032] The inert gas supply unit 6 is a supply port for supplying an inert gas such as nitrogen. The inert gas supply unit 6 is provided at the tip of the string-like member 4 and is embedded in the solid fuel 2 together with the string-like member 4. Multiple inert gas supply units 6 are provided at intervals (for example, 2 to 3 m apart) in the longitudinal direction of the string-like member 4. By providing multiple inert gas supply units 6 in this way, at least one inert gas supply unit 6 is positioned in the central part X of the solid fuel 2 that could become a hot spot. It is preferable that the inert gas supply unit 6 be positioned close to the temperature detection unit 5 so as to form a pair. Specifically, it is preferable that the distance between the pair of inert gas supply units 6 and the temperature detection unit 5 is, for example, 10 cm or less.

[0033] The control unit 7 is located outside the storage tank 3. Based on the temperature information detected by the temperature detection unit 5, the control unit 7 controls the supply of inert gas from the inert gas supply unit 6 to the solid fuel 2. The control unit 7 is composed of, for example, a personal computer.

[0034] As shown in Figures 2 and 3, the string-like member 4 comprises an outer cylindrical portion 4a located on the outer circumference and an inner cylindrical portion 4b located on the inner circumference.

[0035] The outer cylinder portion 4a is made of flexible metal and is grounded. The temperature detection unit 5 and the inert gas supply unit 6 are provided in the outer cylinder portion 4a. Specifically, if the outer cylinder portion 4a includes a metal mesh portion woven from metal wires, the temperature detection unit 5 and the inert gas supply unit 6 are fixed in a state woven into the metal mesh portion. Similarly, the signal line 5a of the temperature detection unit 5 and the signal line 6a of the inert gas supply unit 6 are also fixed in a state woven into the metal mesh portion. Each signal line 5a and 6a is guided outside the storage tank 3 together with the string-like member 4 and connected to the control unit 7. The signal line 5a is for transmitting temperature information to the control unit 7. The signal line 6a is for transmitting control information from the control unit 7 to the inert gas supply unit 6.

[0036] The inner cylinder portion 4b is preferably made of a flexible and antistatic material such as polyvinyl chloride. The internal space of the inner cylinder portion 4b constitutes an inert gas flow passage 10 that circulates inert gas to the inert gas supply unit 6. The inert gas flow passage 10 extends along the longitudinal direction of the string-like member 4 and is connected to an inert gas source 11 (see Figure 1) outside the storage tank 3. The inert gas source 11 is a cylinder in which inert gas (such as nitrogen) is stored or an inert gas generator. The control unit 7 controls the supply of inert gas from the inert gas source 11 to the inert gas flow passage 10 based on the temperature information detected by the temperature detection unit 5.

[0037] The inert gas supply unit 6 includes an opening / closing mechanism 12 that can select between an open state (see arrow R in Figure 3) in which inert gas is supplied and a closed state in which inert gas is not supplied. When the opening / closing mechanism 12 is in the open state, the inert gas passage 10 communicates with the external space of the string-like member 4, and the inert gas in the inert gas passage 10 is supplied to the solid fuel 2. The opening / closing mechanism 12 is composed of, for example, an aperture mechanism having a plurality of aperture blades 12a, but is not limited thereto. However, in the case of an aperture mechanism, there is an advantage in that the opening area can be finely adjusted and the amount of inert gas supplied can be easily adjusted. The control unit 7 controls the opening and closing operation of the opening / closing mechanism 12 by transmitting control information (information to select the open or closed state) to the opening / closing mechanism 12 via the signal line 6a.

[0038] The temperature detection unit 5 includes a position detection unit 13 that transmits the position information of the temperature detection unit 5 to the control unit 7. The position detection unit 13 is a sensor that detects the position information of the temperature detection unit 5 using, for example, GPS, Wi-Fi (registered trademark), Bluetooth (registered trademark), etc. The position detection unit 13 wirelessly transmits the position information of the temperature detection unit 5 to the receiving unit 7a of the control unit 7.

[0039] Next, a method for monitoring a storage tank using the monitoring device 1 configured as described above will be explained.

[0040] First, each temperature detection unit 5 detects the temperature information of the solid fuel 2 stored in the storage tank 3. Next, the temperature information detected by each temperature detection unit 5 is transmitted to the control unit 7 via the signal line 5a. At this time, the position detection unit 13 wirelessly transmits the position information of each temperature detection unit 5 to the control unit 7. Based on the position information, the control unit 7 determines which temperature detection unit 5 is located at the center X of the solid fuel 2. When the temperature information of the temperature detection unit 5 located at the center X of the solid fuel 2 exceeds a set threshold (set temperature), the control unit 7 transmits control information to the inert gas supply unit 6 adjacent to the temperature detection unit 5 via the signal line 6a to open the opening / closing mechanism 12. The control information to open the opening / closing mechanism 12 may be transmitted automatically by the control unit 7 or manually by the administrator. As a result, the opening / closing mechanism 12 of the inert gas supply unit 6 located at the center X of the solid fuel 2 opens, and inert gas is supplied to the center X of the solid fuel 2. As a result, the central part X of the solid fuel 2 is cooled, and the oxygen barrier effect (oxidation suppression effect) reliably suppresses spontaneous combustion caused by abnormal heat generation of the solid fuel 2.

[0041] In this case, it is preferable that the control unit 7 opens only the opening / closing mechanism 12 of the inert gas supply unit 6 located at the center X of the solid fuel 2 when the temperature information of the temperature detection unit 5 located at the center X of the solid fuel 2 exceeds a set threshold. This allows the inert gas to be efficiently supplied to the center X of the solid fuel 2.

[0042] Furthermore, it is preferable that the control unit 7 adjusts the set threshold based on the position information of the temperature detection unit 5. In this way, even if the temperature detection unit 5 is positioned away from the desired location, the set threshold can be adjusted to take that positional deviation into account. A specific method for adjusting the set threshold is to decrease the value of the set threshold as the position of the temperature detection unit 5 moves away from the center X of the solid fuel 2. This takes into account the tendency for the temperature of the solid fuel 2 to decrease as it moves away from the center X when the center X of the solid fuel 2 is a hot spot.

[0043] Furthermore, the present invention is not limited to the configuration of the above embodiments, nor is it limited to the effects described above. The present invention can be modified in various ways without departing from the spirit of the invention.

[0044] In the above embodiment, a case was described in which abnormal heat generation of the solid fuel 2 is detected based on the temperature information of the temperature detection unit 5 located in the center X of the solid fuel 2, but the embodiment is not limited to this. If the temperature information of at least one of the multiple temperature detection units 5 exceeds a set threshold, an inert gas may be supplied from at least one inert gas supply unit 6.

[0045] In the above embodiment, the temperature detection unit 5 and / or inert gas supply unit 6 may be provided in multiple locations at intervals in the circumferential direction of the string-like member 4. This allows for more accurate detection of the temperature information of the solid fuel 2 and for even supply of inert gas over a wide area of ​​the solid fuel 2. It is preferable that the temperature detection unit 5 and / or inert gas supply unit 6 be provided in multiple locations at intervals in both the circumferential and longitudinal directions of the string-like member 4.

[0046] In the above embodiment, a case was described in which a position detection unit 13 is provided for each temperature detection unit 5 and the position information of each temperature detection unit 5 is transmitted to the control unit 7. However, a position detection unit may also be provided for each inert gas supply unit 6 and the position information of each inert gas supply unit 6 may be transmitted to the control unit 7. In this way, if abnormal heat generation occurs in the solid fuel 2, inert gas can be reliably supplied from the inert gas supply unit 6 closest to the point of occurrence.

[0047] In the above embodiment, the temperature information of the solid fuel 2 detected by the temperature detection unit 5 may be transmitted wirelessly to the control unit 7. Furthermore, control information (information for selecting the open or closed state) of the opening / closing mechanism 12 of the inert gas supply unit 6 may be transmitted wirelessly from the control unit 7. Additionally, the position information of the temperature detection unit 5 detected by the position detection unit 13 may be transmitted via wired connection to the control unit 7. In other words, the method of communication for various types of information is not particularly limited.

[0048] In the above embodiment, the temperature detection unit 5 may also serve as a combustible gas detection unit for detecting combustible gases (such as methane or CO). Alternatively, multiple combustible gas detection units may be provided separately from the temperature detection unit 5, spaced apart in the longitudinal direction of the string-like member 4. When combustible gas detection units are provided in this manner, it is preferable that the control unit 7 controls the supply of inert gas from the inert gas supply unit 6 based on the temperature information detected by the temperature detection unit 5 and the combustible gas information detected by the combustible gas detection units (for example, the concentration of the combustible gas or information corresponding to the concentration). In this way, combustible gases generated along with the heat generation of the solid fuel 2 can also be taken into consideration, and abnormal heat generation within the solid fuel 2 can be detected. When combustible gas detection units are provided separately from the temperature detection unit 5, it is preferable that multiple combustible gas detection units be provided at intervals, similar to the temperature detection unit 5, and that positional information be detected. Furthermore, it is preferable that the combustible gas detection units be arranged in close proximity to the temperature detection unit 5 and the inert gas supply unit 6. [Explanation of Symbols]

[0049] 1 Monitoring device 2 solid fuel 3 Storage tank 4. String-like member 4a Outer cylinder 4b Inner cylinder part 5. Temperature detection unit 6. Inert gas supply unit 7 Control Unit 8 Winding device 9 Pulley 10 Inert gas flow path 11. Inert gas source 12 Opening and closing mechanism 13 Position detection unit X The center of the solid fuel (hot spot)

Claims

1. A monitoring device for a storage tank in which solid fuel is stored, A string-like member suspended from the top of the storage tank toward the center of the solid fuel, Multiple temperature detection units are provided at intervals along the longitudinal direction of the string-like member and are embedded together with the string-like member in the solid fuel. Multiple inert gas supply units are provided at intervals along the longitudinal direction of the string-like member and are embedded together with the string-like member in the solid fuel, Each of the aforementioned inert gas supply units is provided with an opening / closing mechanism, An inert gas flow passage is provided inside the string-like member along the longitudinal direction, and the inert gas flows to each of the inert gas supply sections, A storage tank monitoring device comprising: a control unit that controls the opening and closing operation of the opening and closing mechanism so that the inert gas is supplied to the solid fuel from the corresponding inert gas supply unit based on temperature information detected by the temperature detection unit; and a control unit that controls the opening and closing operation of the opening and closing mechanism.

2. The storage tank monitoring device according to claim 1, further comprising a position detection unit that transmits position information of the temperature detection unit to the control unit.

3. The control unit controls the opening and closing operation of the opening and closing mechanism so that the inert gas is supplied from the corresponding inert gas supply unit when the temperature information detected by the temperature detection unit exceeds a set threshold, The storage tank monitoring device according to claim 2, wherein the setting threshold is adjusted based on the position information.

4. The string-like member is provided with a combustible gas detection unit which is embedded together with the string-like member in the solid fuel, The storage tank monitoring device according to claim 1 or 2, wherein the control unit controls the opening and closing operation of the opening and closing mechanism so that the inert gas is supplied from the corresponding inert gas supply unit, based on the temperature information detected by the temperature detection unit and the combustible gas information detected by the combustible gas detection unit.

5. A storage tank monitoring device according to claim 1 or 2, wherein the solid fuel is a biomass fuel.

6. A method for monitoring a storage tank in which solid fuel is stored, A string-like member is suspended from the top of the storage tank toward the center of the solid fuel. Multiple temperature detection units are provided at intervals along the longitudinal direction in the portion of the string-like member that is embedded in the solid fuel. Multiple inert gas supply units are provided at intervals in the longitudinal direction in the portion of the string-like member that is embedded in the solid fuel. Each of the aforementioned inert gas supply units is provided with an opening / closing mechanism. An inert gas flow passage is provided inside the string-like member along the longitudinal direction to circulate the inert gas to each of the inert gas supply sections. A method for monitoring a storage tank, characterized in that, based on temperature information detected by the temperature detection unit, the opening and closing operation of the opening and closing mechanism is controlled so that the inert gas is supplied from the corresponding inert gas supply unit.

7. The method for monitoring a storage tank according to claim 6, wherein the string-like member is embedded in the solid fuel with slack.

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