Ash treatment system

Abstract

To provide an ash treatment system which can promptly detect an occurrence of a bridge in the vicinity of a receiving port.SOLUTION: An ash treatment system 1 for treating ashes removed from a combustion furnace A includes an ash treatment unit 3 which cools down the ashes with water and transports the cooled ashes, and a receiving port hydrogen sensor 41G. The ash treatment unit 3 has a receiving port 311A for receiving ashes. The receiving port hydrogen sensor 41G can measure a hydrogen concentration within the receiving port 311A.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an ash treatment system.

Background Art

[0002] Conventionally, as a facility for cooling incineration ash discharged from an incinerator, there is known an ash extrusion device that cools the ash in a tank in which cooling water is stored and extrudes the cooled ash.

[0003] In such an ash extrusion device, it is known that hydrogen gas is generated by the reaction between the cooling water made alkaline by cooling the incineration ash (the main component is alkaline) and the metal (aluminum) contained in the incineration ash.

[0004] For example, Patent Document 1 below discloses an explosion prevention device that introduces outside air to the top of the ash discharge section to discharge hydrogen gas in the tank in an incineration ash cooling device including a closed tank having an ash input section and an ash discharge section.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the explosion prevention device described in Patent Document 1 above, when the incineration ash of the incinerator adheres to and grows on the inner wall of the ash discharge pipe (shoot), a state called "bridge" occurs in which the inside of the ash discharge pipe is blocked. And when the ash discharge pipe is blocked by the bridge, the occurrence of the bridge cannot be detected, and there is a possibility that hydrogen gas accumulates in the vicinity of the ash input section over time.

[0007] If an attempt is made to eliminate the bridge after hydrogen gas has accumulated near the ash input section, it becomes a very dangerous operation where an explosion may occur.

[0008] The present invention provides an ash treatment system capable of early detection of the occurrence of a bridge near the inlet.

Means for Solving the Problems

[0009] The present invention [1] is an ash treatment system for treating ash discharged from an incinerator, comprising an ash treatment device that cools the ash with water and conveys the cooled ash, and a hydrogen sensor. The ash treatment device has an inlet for receiving the ash, and the hydrogen sensor is capable of measuring the hydrogen concentration inside the inlet.

[0010] According to such a configuration, when a bridge occurs near the inlet, the hydrogen sensor can detect an increase in the hydrogen concentration inside the inlet.

[0011] Therefore, the occurrence of a bridge near the inlet can be detected early.

[0012] As a result, the bridge elimination operation can be carried out before the risk of explosion increases.

[0013] The present invention [2] is a chute that guides the ash discharged from the incinerator to the ash treatment device, one end of which is connected to the incinerator and the other end of which is connected to the inlet of the ash treatment device, and further comprises a control device capable of receiving a signal from the hydrogen sensor. When the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device executes a warning process to warn of the blockage of the chute.

[0014] According to such a configuration, when the chute is blocked by a bridge near the inlet, hydrogen gas generated inside the ash treatment device may accumulate near the inlet, and the hydrogen concentration near the inlet may increase.

[0015] Therefore, when the hydrogen concentration detected by the hydrogen sensor exceeds the threshold value, it is suspected that a bridge may have occurred near the inlet.

[0016] Therefore, when the hydrogen concentration detected by the hydrogen sensor exceeds the threshold value, the control device executes a warning process to warn of the blockage of the chute.

[0017] As a result, the operator can detect the occurrence of a bridge near the inlet at an early stage and perform bridge elimination work before the risk of explosion increases.

[0018] The present invention [3] includes the ash treatment system according to [1] above, wherein the ash treatment system further includes a control device capable of receiving a signal from the hydrogen sensor, and when the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device executes a water injection process of adding cooling water to the ash treatment device.

[0019] According to such a configuration, when the alkalinity of the cooling water becomes excessively high, the amount of hydrogen gas generated may increase.

[0020] If a bridge occurs in a state where the amount of hydrogen gas generated has increased, the risk of explosion may increase in a short time.

[0021] Therefore, when the hydrogen concentration detected by the hydrogen sensor exceeds the threshold value, the control device executes a water injection process to add cooling water to the ash treatment device.

[0022] As a result, the amount of hydrogen gas generated can be reduced, and an increase in the explosion risk when a bridge occurs can be suppressed.

[0023] The present invention [4] further includes a control device capable of receiving a signal from the hydrogen sensor and a post-combustion grate driving device for driving the post-combustion grate of the incinerator, and when the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device controls the post-combustion grate driving device to adjust the driving speed of the post-combustion grate, including any one of the ash treatment systems of [1] to [3] above.

[0024] According to such a configuration, based on the hydrogen concentration detected by the hydrogen sensor, the driving speed of the post-combustion grate can be adjusted so that the generation amount of hydrogen gas does not excessively increase.

[0025] The present invention [5] includes any one of the ash treatment systems of [1] to [4] above, wherein the ash treatment device includes an ash extrusion device for cooling the ash with water and extruding the cooled ash, and the receiving port is the receiving port of the ash extrusion device.

[0026] The present invention [6] includes the ash treatment system of [5] above, wherein the ash extrusion device has a cooling water tank for immersing and cooling the ash in water.

[0027] The present invention [7] includes the ash treatment system of [5] above, wherein the ash extrusion device has a water spraying means for spraying water on the ash.

[0028] The present invention [8] further includes a control device capable of receiving a signal from the hydrogen sensor, and the ash extrusion device further includes a scraper for extruding the ash and a scraper driving device for driving the scraper. When the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device controls the scraper driving device to adjust the driving timing of the scraper, including any one of the ash treatment systems of [5] to [7] above.

[0029] According to such a configuration, based on the hydrogen concentration detected by the hydrogen sensor, the driving timing of the scraper can be adjusted so that the generation amount of hydrogen gas does not excessively increase.

[0030] The present invention [9] includes the ash treatment system of [1] above, wherein the ash treatment device is provided with a water-cooled conveyor that cools the ash with water and conveys the cooled ash, and the inlet is the inlet of the water-cooled conveyor.

Advantages of the Invention

[0031] According to the ash treatment system of the present invention, the generation of a bridge near the inlet can be detected early.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0033] 1. Ash treatment system As shown in FIG. 1, the ash treatment system 1 treats the ash discharged from the incinerator A in a waste incineration facility. Specifically, the ash treatment system 1 cools the ash discharged from the incinerator A and conveys it to the ash pit B. The ash pit B stores the ash cooled by the ash treatment system 1. The ash contains at least main ash. The ash may contain fly ash. The main ash contains incinerated ash. The main ash may contain the ash that has fallen from the gaps of the grate of the incinerator A.

[0034] The ash treatment system 1 includes a chute 2 (see FIG. 2), an ash treatment device 3, and a hydrogen concentration detection system 4.

[0035] In the following description, as shown in FIG. 2, a case where the ash treatment system 1 is applied to a stoker (grate) type incinerator will be taken as an example for explanation. The stoker type incinerator sequentially includes a drying grate A11, a combustion grate A12, and a post-combustion grate A13 from the waste inlet A1 to the ash discharge port A2.

[0036] (1) Chute The chute 2 guides the incinerated ash to the ash treatment device 3. Specifically, the chute 2 guides the incinerated ash to an ash extrusion device 31 described later. One end of the chute 2 is connected to the discharge port A2 of the incinerator A. The other end of the chute 2 is connected to the receiving port 311A (see FIG. 3) of the ash extrusion device 31.

[0037] (2) Ash treatment device The ash treatment device 3 cools the ash with water and conveys the cooled ash toward the ash pit B. Specifically, the ash treatment device 3 includes an ash extrusion device 31, a fallen ash conveyance path 32 as an example of an upstream conveyance path, a boiler-attached ash conveyance path 33 as an example of an upstream conveyance path, and a downstream conveyance path 34.

[0038] (2-1) Ash extrusion device As shown in FIG. 3, the ash extrusion device 31 cools the ash with water and extrudes the cooled ash. In this embodiment, the ash extrusion device 31 is a water-sealed type. Specifically, the ash extrusion device 31 includes a cooling water tank 311, a scraper 312, and a scraper drive device 313.

[0039] The cooling water tank 311 is a water tank for immersing ash in water for cooling. The cooling water tank 311 has a substantially box shape extending in the horizontal direction. Cooling water W is stored in the cooling water tank 311. The ash that has passed through the chute 2 and entered the cooling water tank 311 is cooled by the cooling water W. The cooling water tank 311 has an inlet 311A and an outlet 311B. That is, the ash extrusion device 31 has the inlet 311A.

[0040] The inlet 311A is disposed on the upper wall of the cooling water tank 311. The inlet 311A is located above the water level L of the cooling water W. The inlet 311A is capable of receiving ash. The ash that has passed through the chute 2 enters the cooling water tank 311 through the inlet 311A.

[0041] The outlet 311B is disposed at one end of the cooling water tank 311 in the horizontal direction. The outlet 311B is disposed away from the inlet 311A in the horizontal direction. The outlet 311B is located above the water level L of the cooling water W. The ash immersed in the cooling water W is discharged out of the cooling water tank 311 through the outlet 311B.

[0042] The bottom wall 3111 of the cooling water tank 311 has a deepest part 3111A and an inclined part 3111B. The deepest part 3111A is disposed away below the inlet 311A. The depth of the cooling water W is the deepest at the deepest part 3111A. The inclined part 3111B inclines upward as it approaches the outlet 311B from the deepest part 3111A. The ash in the cooling water tank 311 is pushed by the scraper 312 from the deepest part 3111A toward the outlet 311B, climbs up the inclined part 3111B, and is discharged from the outlet 311B.

[0043] The scraper 312 is disposed in the cooling water tank 311. The scraper 312 extrudes the ash in the cooling water tank 311. Specifically, the scraper 312 pushes the ash on the deepest part 3111A toward the discharge port 311B. The scraper 312 is repeatedly movable between a first position (refer to the virtual line in FIG. 3) and a second position (refer to the solid line in FIG. 3). When the scraper 312 moves from the first position to the second position, it pushes the ash on the deepest part 3111A toward the discharge port 311B.

[0044] The scraper driving device 313 drives the scraper 312. Examples of the scraper driving device 313 include a hydraulic cylinder.

[0045] (2-2) Ash fall conveyance path As shown in FIG. 2, the ash fall conveyance path 32 is a conveyance path for conveying the fallen ash to the ash extrusion device 31. The ash fall conveyance path 32 is disposed below the incinerator A. The ash fall conveyance path 32 is disposed below the drying grate A11, the combustion grate A12, and the afterburning grate A13. The ash fall conveyance path 32 can receive the fallen ash dropped from each of the drying grate A11, the combustion grate A12, and the afterburning grate A13. The ash fall conveyance path 32 is connected to the ash extrusion device 31 via, for example, the chute 2. A drag chain conveyor is disposed in the ash fall conveyance path 32. The fallen ash in the ash fall conveyance path 32 is conveyed toward the ash extrusion device 31 by the drag chain conveyor.

[0046] (2-3) Boiler adhering ash conveyance path The boiler-attached ash conveying path 33 is a conveying path for conveying the fly ash adhering to the boiler 5 to the ash extrusion device 31. The boiler-attached ash conveying path 33 is connected to the ash extrusion device 31. The boiler 5 is provided in an exhaust gas treatment device for treating the exhaust gas discharged from the incinerator A. The boiler 5 boils water by utilizing the heat of the exhaust gas. The steam obtained in the boiler 5 is used, for example, for power generation. Here, fly ash contained in the exhaust gas adheres to the boiler 5. The fly ash adhering to the boiler 5 is removed, for example, by soot blowing, and is conveyed to the ash extrusion device 31 through the boiler-attached ash conveying path 33. A scraper conveyor is disposed in the boiler-attached ash conveying path 33. The fly ash in the boiler-attached ash conveying path 33 is conveyed toward the ash extrusion device 31 by the scraper conveyor.

[0047] (2-4) Downstream Conveying Path The downstream conveying path 34 is a conveying path for conveying the ash extruded from the ash extrusion device 31 toward the ash pit B. The downstream conveying path 34 can receive the ash extruded from the ash extrusion device 31. A scraper conveyor is disposed in the downstream conveying path 34. The ash in the downstream conveying path 34 is conveyed toward the ash pit B by the scraper conveyor.

[0048] (3) Hydrogen Concentration Detection System The hydrogen concentration detection system 4 detects the hydrogen concentration in the ash treatment device 3.

[0049] In the ash treatment device 3, since the ash (the main component is alkaline) is cooled by the cooling water W (see FIG. 3), the cooling water W becomes alkaline. In particular, when the cooling water W is circulated, the alkalinity of the cooling water W becomes stronger. Then, a metal (for example, aluminum) contained in the ash reacts with the alkaline cooling water W, and hydrogen is generated. If the generated hydrogen stays, an explosion due to the stayed hydrogen may occur.

[0050] Therefore, in the present invention, the hydrogen concentration detection system 4 monitors the hydrogen concentration in the ash treatment device 3. Specifically, the hydrogen concentration detection system 4 includes a plurality of hydrogen sensors 41 and a control device 42. That is, the ash treatment system 1 includes a plurality of hydrogen sensors 41.

[0051] (3-1) Hydrogen Sensor The plurality of hydrogen sensors 41 can measure the hydrogen concentration in the ash treatment device 3. That is, the hydrogen concentration detection system 4 can measure the hydrogen concentration at a plurality of locations in the ash treatment device 3. Specifically, the plurality of hydrogen sensors 41 include a plurality of upstream hydrogen sensors 41A, 41B, 41C, 41D, a plurality of downstream hydrogen sensors 41E, 41F, and an inlet hydrogen sensor 41G.

[0052] The upstream hydrogen sensors 41A, 41B can measure the hydrogen concentration in the fly ash conveying path 32. The upstream hydrogen sensors 41A, 41B are arranged apart from each other in the direction in which the fly ash conveying path 32 extends. Thereby, the upstream hydrogen sensors 41A, 41B continuously measure the hydrogen concentrations at two locations separated from each other in the fly ash conveying path 32. Note that the number of hydrogen sensors 41 attached to the fly ash conveying path 32 is not limited. The number of hydrogen sensors 41 attached to the fly ash conveying path 32 may be one, or may be three or more.

[0053] The upstream hydrogen sensors 41C, 41D can measure the hydrogen concentration in the boiler-attached ash conveying path 33. The upstream hydrogen sensors 41C, 41D are arranged apart from each other in the direction in which the boiler-attached ash conveying path 33 extends. Thereby, the upstream hydrogen sensors 41C, 41D continuously measure the hydrogen concentrations at two locations separated from each other in the boiler-attached ash conveying path 33. Note that the number of hydrogen sensors 41 attached to the boiler-attached ash conveying path 33 is not limited. The number of hydrogen sensors 41 attached to the boiler-attached ash conveying path 33 may be one, or may be three or more.

[0054] The downstream hydrogen sensors 41E and 41F can measure the hydrogen concentration in the downstream conveyance path 34. The downstream hydrogen sensors 41E and 41F are arranged apart from each other in the direction in which the downstream conveyance path 34 extends. Thereby, the downstream hydrogen sensors 41E and 41F continuously measure the hydrogen concentrations at two locations apart from each other in the downstream conveyance path 34. Note that the number of hydrogen sensors 41 attached to the downstream conveyance path 34 is not limited. The number of hydrogen sensors 41 attached to the downstream conveyance path 34 may be one, or may be three or more.

[0055] As shown in FIG. 3, the inlet hydrogen sensor 41G can measure the hydrogen concentration in the inlet 311A of the ash extrusion device 31. The inlet hydrogen sensor 41G continuously measures the hydrogen concentration in the inlet 311A of the ash extrusion device 31.

[0056] Each of the plurality of hydrogen sensors 41 is preferably a wireless hydrogen detection device. Each of the plurality of hydrogen sensors 41 may be a wired hydrogen detection device. The generated hydrogen stays in an unexpected location in the ash treatment device 3. Therefore, it is preferable to perform multi-point monitoring of the hydrogen concentration using a small wireless hydrogen sensor and a communication device that can be easily attached and measured anywhere. By performing multi-point monitoring of the hydrogen concentration, it is possible to predict the retention status and accident risk of hydrogen from the fluctuation tendency of the hydrogen concentration at each installation location of the hydrogen sensor. Then, when it is determined that the explosion risk has increased, an explosion can be avoided by measures such as promoting ventilation of the entire facility or forcibly ventilating the location where the explosion risk has increased pinpoint. Note that when it is determined that the hydrogen concentration has gradually increased and the explosion risk has increased, it is preferable to promote ventilation of the entire facility, and when it is determined that the explosion risk has increased due to a rapid increase in the hydrogen concentration, it is preferable to forcibly ventilate the location where the explosion risk has increased pinpoint (such as blowing + opening to the atmosphere).

[0057] (3-2) Control device As shown in FIGS. 2 and 3, the control device 42 can receive signals from each of the plurality of hydrogen sensors 41.

[0058] As shown in FIG. 4, the ash treatment system 1 may further include a display device 51, a warning light 52, a fan 53 of the falling ash conveyance path 32, a fan 54 of the boiler-attached ash conveyance path 33, a fan 55 of the downstream conveyance path 34, a fan 56 of the ash extrusion device 31, and a post-combustion grate drive device 57.

[0059] The display device 51 is arranged, for example, in the control room of the waste incineration facility. The warning light 52 is attached to, for example, the ash extrusion device 31. The fan 53 is attached to the falling ash conveyance path 32. The fan 54 is attached to the boiler-attached ash conveyance path 33. The fan 55 is attached to the downstream conveyance path 34. The fan 56 is attached to the ash extrusion device 31. The post-combustion grate drive device 57 is connected to the post-combustion grate A13. The post-combustion grate drive device 57 drives the post-combustion grate A13 of the incinerator A. Note that the control device 42 may be integrated with other control devices of the incinerator.

[0060] The control device 42 controls the display device 51, the warning light 52, the fan 53 of the falling ash conveyance path 32, the fan 54 of the boiler-attached ash conveyance path 33, the fan 55 of the downstream conveyance path 34, the fan 56 of the ash extrusion device 31, the post-combustion grate drive device 57, and the scraper drive device 313 by wireless connection or wired connection.

[0061] As shown in FIG. 5, the control device 42 monitors the hydrogen concentration in the falling ash conveyance path 32 based on signals from the upstream hydrogen sensors 41A and 41B (see FIG. 2). When the hydrogen concentration in the falling ash conveyance path 32 exceeds a threshold value (first threshold value) (S1: YES), the control device 42 performs ventilation processing on the falling ash conveyance path 32 (S2). In the ventilation processing of the falling ash conveyance path 32, the control device 42 operates the fan 53 (see FIG. 4) to ventilate the inside of the falling ash conveyance path 32.

[0062] In addition, in parallel with the processing for the falling ash conveyance path 32, the control device 42 also monitors the internal hydrogen concentration for the boiler-attached ash conveyance path 33 and the downstream conveyance path 34, and performs ventilation processing when the hydrogen concentration exceeds the threshold value.

[0063] Specifically, the control device 42 monitors the hydrogen concentration in the boiler fouling ash conveyance path 33 based on signals from the upstream hydrogen sensors 41C and 41D (see FIG. 2). When the hydrogen concentration in the boiler fouling ash conveyance path 33 exceeds a threshold value (second threshold value), the control device 42 performs ventilation processing on the boiler fouling ash conveyance path 33. In the ventilation processing of the boiler fouling ash conveyance path 33, the control device 42 operates the fan 54 (see FIG. 4) to ventilate the inside of the boiler fouling ash conveyance path 33. The second threshold value can be set independently of the first threshold value. The second threshold value may be the same as or different from the first threshold value.

[0064] Further, the control device 42 monitors the hydrogen concentration in the downstream conveyance path 34 based on signals from the downstream hydrogen sensors 41E and 41F (see FIG. 2). When the hydrogen concentration in the downstream conveyance path 34 exceeds a threshold value (third threshold value), the control device 42 performs ventilation processing on the downstream conveyance path 34. In the ventilation processing of the downstream conveyance path 34, the control device 42 operates the fan 55 (see FIG. 4) to ventilate the inside of the downstream conveyance path 34. The third threshold value can be set independently of the first threshold value and the second threshold value. The third threshold value may be the same as or different from the first threshold value and the second threshold value. The third threshold value is preferably higher than the first threshold value and the second threshold value.

[0065] Then, when the hydrogen concentration becomes equal to or lower than the safety value (S1: NO, S3: YES, S4: YES), the control device 42 stops the ventilation processing (S5).

[0066] Also, as shown in FIG. 6, the control device 42 monitors the hydrogen concentration in the inlet 311A of the ash extrusion device 31 based on a signal from the inlet hydrogen sensor 41G (see FIG. 3). When the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds a threshold value (fourth threshold value) (S11: YES), the control device 42 executes warning processing (S12). The fourth threshold value can be set independently of the first threshold value, the second threshold value, and the third threshold value. The fourth threshold value may be the same as or different from the first threshold value, the second threshold value, and the third threshold value. The fourth threshold value is preferably higher than the first threshold value, the second threshold value, and the third threshold value.

[0067] Here, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value (the fourth threshold value) or adheres to and grows on the inner wall of the chute 2 (see FIG. 3), a state called a "bridge" occurs where the inside of the chute 2 is blocked. If the chute 2 is blocked, there is a possibility that the hydrogen in the ash extrusion device 31 that had escaped to the incinerator side when the chute 2 was not blocked may be retained in the vicinity of the inlet 311A.

[0068] Therefore, in the warning process, the control device 42, for example, displays on the display device 51 (see FIG. 4) that there is a possibility that the chute 2 is blocked, and activates the warning lamp 52 (see FIG. 4) to warn of the blockage of the chute 2.

[0069] Also, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value, it is conceivable that the alkalinity of the cooling water has become excessively strong and the amount of hydrogen generated has increased.

[0070] Therefore, the control device 42 may execute a water injection process of adding cooling water together with the warning process (S12). Note that the water injection process may be executed independently of the warning process (S12) based on different threshold values and safety values from the warning process (S12).

[0071] When the hydrogen concentration becomes equal to or lower than the safety value (S11: NO, S13: YES, S14: YES), the control device 42 cancels the warning (S15).

[0072] Note that the hydrogen concentration distribution for each location of the hydrogen sensor, the threshold value of the hydrogen concentration, and the safety value may be determined by machine learning or the like.

[0073] 2. Operational Effects (1) According to the ash treatment system 1, as shown in FIG. 3, the hydrogen concentration in the inlet 311A of the ash extrusion device 31 can be measured by the inlet hydrogen sensor 41G.

[0074] Therefore, when a bridge occurs near the inlet 311A, the inlet hydrogen sensor 41G can detect an increase in the hydrogen concentration inside the inlet 311A.

[0075] Therefore, the occurrence of a bridge near the inlet 311A can be detected at an early stage.

[0076] As a result, the bridge elimination work can be carried out before the risk of explosion increases.

[0077] (2) According to the ash treatment system 1, when the chute 2 is blocked by a bridge near the inlet 311A, the hydrogen gas generated in the ash extrusion device 31 may accumulate near the inlet 311A, and the hydrogen concentration near the inlet 311A may increase.

[0078] Therefore, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value, it is suspected that a bridge may have occurred near the inlet 311A.

[0079] Therefore, as shown in FIG. 6, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value (S11: YES), the control device 42 executes a warning process (S12) to warn of the blockage of the chute 2.

[0080] Thereby, the operator can discover the occurrence of a bridge near the inlet 311A at an early stage and carry out the bridge elimination work before the risk of explosion increases.

[0081] (3) According to the ash treatment system 1, when the alkalinity of the cooling water becomes excessively high, the amount of hydrogen gas generated may increase.

[0082] If a bridge occurs in a state where the amount of hydrogen gas generated has increased, the risk of explosion may increase in a short time.

[0083] Therefore, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value, the control device 42 may execute a water injection process to add cooling water to the ash treatment device, along with a warning process (S12).

[0084] Thereby, the generation amount of hydrogen gas can be reduced, and an increase in the explosion risk when a bridge occurs can be suppressed.

[0085] 3. Modification Example Hereinafter, the modification example will be described. In the modification example, the same members as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0086] (1) The ash treatment device 3 may not have the boiler-attached ash conveyance path 33. The boiler-attached ash (fly ash) may be conveyed to a fly ash treatment facility different from the ash treatment device 3 and may be solidified in the fly ash treatment facility.

[0087] (2) As shown in FIG. 7, the ash extrusion device 31 may be of the water spray type. Specifically, the ash extrusion device 31 sprays cooling water on the ash in the cooling water tank 311 without immersing the ash in the cooling water in the cooling water tank 311. The ash extrusion device 31 has a nozzle 61 as an example of the water spray means. The nozzle 61 sprays water on the ash in the cooling water tank 311 to cool the ash. The cooled ash is pushed by the scraper 312 and discharged from the discharge port 311B.

[0088] (3) Instead of the ash extrusion device 31, the ash treatment device 3 may be provided with a water-cooled conveyor 71. As shown in FIG. 8, the water-cooled conveyor 71 may be of the water-sealed type in which the ash is immersed in the cooling water W stored in the water-cooled conveyor 71 for cooling, or as shown in FIG. 9, may be of the water spray type in which the ash is cooled by water sprayed from the nozzle 72.

[0089] The water-cooled conveyor 71 cools the ash with water and conveys the cooled ash. A drag chain conveyor is arranged in the water-cooled conveyor 71. The ash in the water-cooled conveyor 71 is conveyed by the drag chain conveyor toward the ash pit B (see FIG. 1).

[0090] The inlet hydrogen sensor 41G may be able to measure the hydrogen concentration inside the inlet 311A of the water-cooled conveyor 71.

[0091] According to this modification, when the water-cooled conveyor 71 is provided instead of the ash extrusion device 31 and the ash is cooled by the water-cooled conveyor 71, the inlet hydrogen sensor 41G can monitor the hydrogen concentration inside the water-cooled conveyor 71, which is assumed to be the main source of hydrogen gas.

[0092] (4) The water-cooled conveyor 71 may be continuous with the falling ash conveying path 32 (see FIG. 2).

[0093] (5) When the hydrogen concentration detected by the inlet hydrogen sensor 41G (see FIG. 3) exceeds the threshold value, the control device 42 may control the afterburning fire grate drive device 57 to adjust the drive speed of the afterburning fire grate A13 (see FIG. 2) as shown in FIG. 4.

[0094] According to this modification, based on the hydrogen concentration detected by the inlet hydrogen sensor 41G, the drive speed of the afterburning fire grate A13 can be adjusted so that the generation amount of hydrogen gas does not increase excessively.

[0095] Specifically, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value, the control device 42 controls the afterburning fire grate drive device 57 to slow down the drive speed of the afterburning fire grate A13.

[0096] By slowing down the drive speed of the afterburning fire grate A13, the amount of incinerated ash supplied to the ash extrusion device 31 per unit time can be reduced, and the amount of hydrogen generated in the ash extrusion device 31 can be reduced.

[0097] (6) When the hydrogen concentration detected by the inlet hydrogen sensor 41G (see FIG. 3) exceeds the threshold value, the control device 42 may control the scraper drive device 313 to adjust the drive timing of the scraper 312 (see FIG. 3).

[0098] According to this modification example, based on the hydrogen concentration detected by the inlet hydrogen sensor 41G, the driving timing of the scraper 312 can be adjusted so that the generation amount of hydrogen gas does not increase excessively.

[0099] Specifically, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value, the control device 42 controls the scraper driving device 313 to adjust the driving timing of the scraper 312 so that the driving interval of the scraper 312 becomes longer than the set value. Also, by controlling the scraper driving device 313, the driving timing of the scraper 312 is adjusted so that the driving timing of the scraper 312 is delayed with respect to the driving timing of the afterburning grate driving device 57.

[0100] (7) Even in Modification Examples (1) to (6), the same operational effects as those of the embodiment can be obtained.

Explanation of Reference Numerals

[0101] 1 Ash treatment system 2 Shoot 3 Ash treatment device 31 Ash extrusion device 311 Cooling water tank 311A Inlet 312 Scraper 313 Scraper driving device 41G Inlet hydrogen sensor (an example of a hydrogen sensor) 42 Control device 57 Afterburning grate driving device 61 Nozzle (an example of a water spraying means) 71 Water-cooled conveyor A Incinerator A13 Afterburning grate

Claims

1. An ash treatment system for treating ash discharged from an incinerator, comprising: an ash treatment device that cools the ash with water and conveys the cooled ash; a hydrogen sensor and wherein the ash treatment device has an inlet for receiving the ash, and the hydrogen sensor is capable of measuring the hydrogen concentration inside the inlet. An ash treatment system.

2. The ash treatment system further comprises: a chute for guiding the ash discharged from the incinerator to the ash treatment device, one end of which is connected to the incinerator and the other end of which is connected to the inlet of the ash treatment device; a control device capable of receiving a signal from the hydrogen sensor and wherein when the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device executes a warning process for warning of blockage of the chute. The ash treatment system according to Claim 1.

3. The ash treatment system further comprises: a control device capable of receiving a signal from the hydrogen sensor, wherein when the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device executes a water injection process for adding cooling water to the ash treatment device. The ash treatment system according to Claim 1.

4. The ash treatment system further comprises: a control device capable of receiving a signal from the hydrogen sensor; a post-combustion grate driving device for driving the post-combustion grate of the incinerator and wherein when the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device controls the post-combustion grate driving device to adjust the driving speed of the post-combustion grate. The ash treatment system according to Claim 1.

5. The ash treatment device comprises: an ash extrusion device that cools the ash with water and extrudes the cooled ash, and the inlet is the inlet of the ash extrusion device. The ash treatment system according to Claim 1.

6. The ash extrusion device has a cooling water tank for immersing the ash in water for cooling. The ash treatment system according to Claim 5.

7. The ash extrusion device has a water spraying means for spraying water on the ash. The ash treatment system according to Claim 5.

8. The ash treatment system further comprises: a control device capable of receiving a signal from the hydrogen sensor, and the ash extrusion device comprises: a scraper for extruding the ash; a scraper driving device for driving the scraper and The ash treatment system according to claim 5, wherein when the hydrogen concentration detected by the hydrogen sensor exceeds a threshold value, the control device controls the scraper drive device to adjust the drive timing of the scraper.

9. The ash treatment device comprises a water-cooled conveyor that cools the ash with water and conveys the cooled ash. The ash treatment system according to claim 1, wherein the inlet is an inlet of the water-cooled conveyor.

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