Ash treatment system and hydrogen concentration detection system

Abstract

An ash treatment system (1) for treating ash discharged from an incinerator (A) comprises: an ash treatment device (3) that cools the ash with water and transports the cooled ash; and a hydrogen sensor (41) that can measure the hydrogen concentration in the ash treatment device (3).

Description

Ash disposal system and hydrogen concentration detection system

[0001] The present invention relates to an ash treatment system and a hydrogen concentration detection system.

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

[0003] It is known that in such ash extrusion devices, hydrogen gas is produced by a reaction between the cooling water, which has become alkaline by cooling the incineration ash (the main component of which is alkaline), and the metal (aluminum) contained in the incineration ash.

[0004] For example, Patent Document 1 below discloses an explosion prevention device in an incineration ash cooling device equipped with a sealed tank having an ash inlet section and an ash outlet section, which introduces outside air into the top of the ash outlet section to discharge hydrogen gas from the tank.

[0005] Patent No. 3501626

[0006] The explosion prevention device described in the above-mentioned Patent Document 1 is unable to grasp the concentration or flow of hydrogen gas.

[0007] As a result, if the hydrogen gas generated in the tank does not flow to the ash discharge section but instead flows into peripheral equipment connected to the incineration ash cooling device, there have been many cases where the hydrogen that has flowed in has accumulated in unexpected places and caused an explosion.In addition, because the hydrogen comes from garbage, it is difficult to predict the amount and timing of hydrogen generation.

[0008] The present invention provides an ash treatment system and a hydrogen concentration detection system that can prevent hydrogen explosions from occurring in the ash treatment device.

[0009] The present invention [1] includes an ash treatment system for treating ash discharged from an incinerator, the ash treatment system comprising an ash treatment device that cools the ash with water and transports the cooled ash, and a hydrogen sensor that can measure the hydrogen concentration within the ash treatment device.

[0010] With this configuration, the hydrogen concentration in the ash treatment device can be monitored by the hydrogen sensor.

[0011] Therefore, the risk of an explosion caused by hydrogen gas can be evaluated based on the hydrogen concentration measured by the hydrogen sensor, and processing can be performed to avoid the explosion.

[0012] As a result, the occurrence of a hydrogen explosion in the ash treatment device can be avoided.

[0013] The present invention [2] includes the ash treatment system of [1] above, in which the ash treatment device comprises an ash extrusion device that cools the ash with water and extrudes the cooled ash, and an upstream transport path connected to the ash extrusion device for transporting the ash, and the hydrogen sensor is an upstream hydrogen sensor that can measure the hydrogen concentration in the upstream transport path.

[0014] With this configuration, even if hydrogen gas generated in the ash pusher flows into the upstream conveying path, the increase in hydrogen concentration in the upstream conveying path can be detected by the upstream hydrogen sensor.

[0015] As a result, a process for avoiding an explosion can be carried out on the upstream transport path.

[0016] The present invention [3] includes the ash treatment system of the above [2], wherein the upstream transport path is a ash transport path for transporting ash that has fallen from the incinerator to the ash extrusion device.

[0017] With this configuration, even if hydrogen gas generated in the ash extrusion device flows into the ash transport path, the increase in hydrogen concentration in the ash transport path can be detected by the upstream hydrogen sensor.

[0018] As a result, processing can be carried out in the dust ash transport path to avoid explosions.

[0019] The present invention [4] includes the ash treatment system according to the above [2], wherein the upstream transport path is a boiler-adhered ash transport path for transporting fly ash adhering to the boiler to the ash push-out device.

[0020] With this configuration, even if hydrogen gas generated in the ash pusher flows into the boiler-adhered ash transport path, the increase in hydrogen concentration in the boiler-adhered ash transport path can be detected by the upstream hydrogen sensor.

[0021] As a result, processing can be carried out in the boiler ash transport path to avoid explosions.

[0022] The present invention [5] includes the ash treatment system of any one of [1] to [4] above, wherein the ash treatment device comprises an ash extrusion device that cools the ash with water and extrudes the cooled ash, and a downstream transport path for transporting the ash extruded from the ash extrusion device, and the hydrogen sensor is a downstream hydrogen sensor that can measure the hydrogen concentration in the downstream transport path.

[0023] With this configuration, hydrogen generated from the wet ash in the downstream transport path can be monitored by the downstream hydrogen sensor.

[0024] Therefore, processing to avoid explosion can be performed on the downstream transport path as well.

[0025] In addition, if the hydrogen concentration in the downstream conveying path rises excessively, for example, when hydrogen gas generated in the ash extrusion device flows into the downstream conveying path, processing can be carried out to avoid explosion, just as in the upstream conveying path.

[0026] The present invention [6] includes the ash treatment system of any one of [2] to [4] above, further comprising a control device capable of receiving a signal from the hydrogen sensor, and wherein the control device performs a ventilation process to ventilate the upstream transport path when the hydrogen concentration in the upstream transport path exceeds a threshold value.

[0027] With this configuration, if the hydrogen concentration measured by the upstream hydrogen sensor exceeds the threshold value and the risk of an explosion due to hydrogen gas in the upstream transport path increases, the upstream transport path can be ventilated to avoid the explosion.

[0028] The present invention [7] includes the ash treatment system of the above [5], further comprising a control device capable of receiving a signal from the hydrogen sensor, and wherein the control device performs a ventilation process to ventilate the downstream transport path when the hydrogen concentration in the downstream transport path exceeds a threshold value.

[0029] With this configuration, if the hydrogen concentration measured by the downstream hydrogen sensor exceeds the threshold value and the risk of an explosion due to hydrogen gas in the downstream transport path increases, the downstream transport path can be ventilated to avoid the explosion.

[0030] The present invention [8] includes the ash treatment system of any one of [2] to [4] above, in which the hydrogen sensor is a wireless hydrogen detection device, the ash treatment system is provided with a plurality of the upstream hydrogen sensors, and the plurality of the upstream hydrogen sensors continuously measure the hydrogen concentration at a plurality of locations separated from one another within the upstream transport path.

[0031] According to this configuration, the flow of hydrogen gas in the upstream transfer path can be estimated by continuously measuring the hydrogen concentration at a plurality of locations that are separated from each other.

[0032] The present invention [9] includes the ash treatment system of [5] above, in which the hydrogen sensor is a wireless hydrogen detection device, the ash treatment system is provided with a plurality of downstream hydrogen sensors, and the plurality of downstream hydrogen sensors continuously measure the hydrogen concentration at a plurality of locations separated from one another within the downstream transport path.

[0033] According to this configuration, the flow of hydrogen gas in the downstream transfer path can be estimated by continuously measuring the hydrogen concentration at a plurality of locations that are separated from each other.

[0034] The present invention

[10] includes the ash treatment system of any one of [2] to [9] above, wherein the ash extrusion device has an inlet for receiving the ash, and the ash treatment system further comprises an inlet hydrogen sensor capable of measuring the hydrogen concentration in the inlet of the ash extrusion device.

[0035] With this configuration, the hydrogen concentration in the ash extrusion device, which is assumed to be the main source of hydrogen gas, can be monitored by the inlet hydrogen sensor.

[0036] The present invention

[11] includes the ash treatment system of any one of [2] to

[10] above, wherein the ash extrusion device has a cooling water tank for immersing the ash in water to cool it.

[0037] The present invention

[12] is an ash treatment system according to any one of the above [2] to

[10] , wherein the ash extrusion device has a water sprinkling means for sprinkling water on the ash to cool the ash.

[0038] The present invention

[13] includes the ash treatment system of the above [1], wherein the ash treatment device cools the ash with water and includes a water-cooled conveyor that transports the cooled ash, and the hydrogen sensor is capable of measuring the hydrogen concentration in the water-cooled conveyor.

[0039] With this configuration, when the ash is cooled by a water-cooled conveyor, the hydrogen concentration in the water-cooled conveyor, which is assumed to be the main source of hydrogen gas, can be monitored.

[0040] The present invention

[14] includes a hydrogen concentration detection system for detecting the hydrogen concentration in an ash treatment device for treating ash discharged from an incinerator, the hydrogen concentration detection system comprising a hydrogen sensor capable of measuring the hydrogen concentration and a control device capable of receiving a signal from the hydrogen sensor.

[0041] With this configuration, the hydrogen concentration in the ash treatment device can be monitored by the hydrogen sensor.

[0042] Therefore, the risk of an explosion caused by hydrogen gas can be evaluated based on the hydrogen concentration measured by the hydrogen sensor, and processing can be performed to avoid the explosion.

[0043] As a result, the occurrence of unexpected explosions in the ash treatment device can be suppressed.

[0044] The present invention

[15] includes the hydrogen concentration detection system of the above

[14] , in which the ash treatment device comprises an ash extrusion device that cools the ash with water and extrudes the cooled ash, and an upstream transport path connected to the ash extrusion device for transporting the ash, and the hydrogen sensor is an upstream hydrogen sensor that can measure the hydrogen concentration in the upstream transport path.

[0045] With this configuration, even if hydrogen gas generated in the ash pusher flows into the upstream conveying path, the increase in hydrogen concentration in the upstream conveying path can be detected by the upstream hydrogen sensor.

[0046] As a result, a process for avoiding an explosion can be carried out on the upstream transport path.

[0047] The present invention

[16] includes the hydrogen concentration detection system of the above

[14] , in which the ash treatment device comprises an ash extrusion device that cools the ash with water and extrudes the cooled ash, and a downstream transport path that is connected to the ash extrusion device and transports the ash extruded from the ash extrusion device, and the hydrogen sensor is a downstream hydrogen sensor that can measure the hydrogen concentration in the downstream transport path.

[0048] With this configuration, hydrogen generated from the wet ash in the downstream transport path can be monitored by the downstream hydrogen sensor.

[0049] In addition, if the hydrogen concentration in the downstream conveying path rises excessively, for example, when hydrogen gas generated in the ash extrusion device flows into the downstream conveying path, processing can be carried out to avoid explosion, just as in the upstream conveying path.

[0050] The present invention

[17] includes the hydrogen concentration detection system of

[15] or

[16] above, wherein the ash extrusion device has an inlet for receiving the ash, and the hydrogen concentration detection system further comprises an inlet hydrogen sensor capable of measuring the hydrogen concentration in the inlet of the ash extrusion device.

[0051] With this configuration, the hydrogen concentration in the ash extrusion device, which is assumed to be the main source of hydrogen gas, can be monitored by the inlet hydrogen sensor.

[0052] According to the ash treatment system and hydrogen concentration detection system of the present invention, it is possible to avoid the occurrence of hydrogen explosions in the ash treatment system.

[0053] FIG. 1 is a block diagram showing a waste incineration facility equipped with an ash treatment system according to one embodiment of the present invention. FIG. 2 is a schematic diagram of the ash treatment system shown in FIG. 1. FIG. 3 is a cross-sectional view of the ash extrusion device shown in FIG. 2. FIG. 4 is a block diagram for explaining the control of the ash treatment system shown in FIG. 2. FIG. 5 is a flowchart of ventilation processing, which is an example of the control of the ash treatment system shown in FIG. 2. FIG. 6 is a flowchart of warning processing, which is an example of the control of the ash treatment system shown in FIG. 2. FIG. 7 is an explanatory diagram for explaining modified example (2). FIG. 8 is an explanatory diagram for explaining modified example (3), showing a water-sealed water-cooled conveyor. FIG. 9 is an explanatory diagram for explaining modified example (3), showing a sprinkler-type water-cooled conveyor.

[0054] 1. Ash Treatment System As shown in Figure 1, ash treatment system 1 treats ash discharged from incinerator A in a waste incineration facility. Specifically, ash treatment system 1 cools the ash discharged from incinerator A and transports it to ash pit B. Ash pit B stores the ash cooled by ash treatment system 1. The ash contains at least bottom ash. The ash may also contain fly ash. The bottom ash contains incineration ash. The bottom ash may also contain dust ash that has fallen through gaps in the grate of incinerator A.

[0055] The ash treatment system 1 includes a chute 2 (see FIG. 2 ), an ash treatment device 3 , and a hydrogen concentration detection system 4 .

[0056] In the following description, the ash treatment system 1 will be described as being applied to a stoker (fire grate) type incinerator, as shown in Figure 2. The stoker type incinerator is equipped with a drying grate A11, a combustion grate A12, and a post-combustion grate A13, in that order, from a waste inlet A1 to an ash outlet A2.

[0057] (1) Chute The chute 2 guides the incineration ash to the ash treatment device 3. More specifically, the chute 2 guides the incineration ash to the ash pushing device 31 described below. One end of the chute 2 is connected to the discharge outlet A2 of the incinerator A. The other end of the chute 2 is connected to the receiving port 311A ​​of the ash pushing device 31 (see Figure 3).

[0058] (2) Ash Treatment Device The ash treatment device 3 cools the ash with water and transports the cooled ash toward the ash pit B. In detail, the ash treatment device 3 includes an ash extrusion device 31, a dust ash transport path 32 as an example of an upstream transport path, a boiler-adhered ash transport path 33 as an example of an upstream transport path, and a downstream transport path 34.

[0059] (2-1) Ash Push-Out Device As shown in Figure 3, the ash push-out device 31 cools ash with water and pushes out the cooled ash. In this embodiment, the ash push-out device 31 is a water-sealed type. More specifically, the ash push-out device 31 includes a cooling water tank 311, a scraper 312, and a scraper drive device 313.

[0060] The cooling water tank 311 is a water tank for immersing the ash in water to cool it. The cooling water tank 311 has a roughly box-like shape extending horizontally. Cooling water W is stored inside the cooling water tank 311. Ash that passes through the chute 2 and enters 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. In other words, the ash extrusion device 31 has the inlet 311A.

[0061] The receiving port 311A ​​is disposed on the upper wall of the cooling water tank 311. The receiving port 311A ​​is located above the water level L of the cooling water W. The receiving port 311A ​​is capable of receiving ash. The ash that has passed through the chute 2 passes through the receiving port 311A ​​and enters the cooling water tank 311.

[0062] The discharge outlet 311B is disposed at one end of the cooling water tank 311 in the horizontal direction. The discharge outlet 311B is disposed apart from the inlet 311A ​​in the horizontal direction. The discharge 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 discharge outlet 311B.

[0063] The bottom wall 3111 of the cooling water tank 311 has a deepest portion 3111A and an inclined portion 3111B. The deepest portion 3111A is located below the inlet 311A ​​at a distance. The depth of the cooling water W is greatest at the deepest portion 3111A. The inclined portion 3111B inclines upward as it approaches the outlet 311B from the deepest portion 3111A. The ash in the cooling water tank 311 is pushed by the scraper 312 from the deepest portion 3111A toward the outlet 311B, moves up the inclined portion 3111B, and is discharged from the outlet 311B.

[0064] Scraper 312 is disposed in cooling water tank 311. Scraper 312 pushes out ash from cooling water tank 311. Specifically, scraper 312 pushes ash on deepest portion 3111A toward discharge outlet 311B. Scraper 312 can repeatedly move between a first position (see phantom lines in FIG. 3 ) and a second position (see solid lines in FIG. 3 ). When scraper 312 moves from the first position to the second position, it pushes ash on deepest portion 3111A toward discharge outlet 311B.

[0065] The scraper driving device 313 drives the scraper 312. The scraper driving device 313 may be, for example, a hydraulic cylinder.

[0066] (2-2) Falling Ash Conveying Path As shown in FIG. 2, the falling ash conveying path 32 is a conveying path for conveying falling ash to the ash pushing device 31. The falling ash conveying path 32 is arranged below the incinerator A. The falling ash conveying path 32 is arranged below the drying grate A11, the combustion grate A12, and the post-combustion grate A13. The falling ash conveying path 32 can receive falling ash that has fallen from each of the drying grate A11, the combustion grate A12, and the post-combustion grate A13. The falling ash conveying path 32 is connected to the ash pushing device 31, for example, via a chute 2. A drag chain conveyor is arranged within the falling ash conveying path 32. The falling ash within the falling ash conveying path 32 is conveyed by the drag chain conveyor toward the ash pushing device 31.

[0067] (2-3) Boiler-Adhered Ash Conveying Path The boiler-adhered ash conveying path 33 is a conveying path for conveying fly ash adhering to the boiler 5 to the ash pushing device 31. The boiler-adhered ash conveying path 33 is connected to the ash pushing device 31. The boiler 5 is provided in an exhaust gas treatment device for treating exhaust gas discharged from the incinerator A. The boiler 5 boils water using the heat of the exhaust gas. The steam obtained by the boiler 5 is used, for example, for power generation. 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 conveyed to the ash pushing device 31 through the boiler-adhered ash conveying path 33. A scraper conveyor is arranged in the boiler-adhered ash conveying path 33. The fly ash in the boiler-adhered ash conveying path 33 is conveyed by the scraper conveyor toward the ash pushing device 31.

[0068] (2-4) Downstream Conveying Path The downstream conveying path 34 is a conveying path for conveying the ash pushed out from the ash pusher 31 toward the ash pit B. The downstream conveying path 34 is capable of receiving the ash pushed out from the ash pusher 31. A scraper conveyor is disposed within the downstream conveying path 34. The ash within the downstream conveying path 34 is conveyed toward the ash pit B by the scraper conveyor.

[0069] (3) Hydrogen Concentration Detection System The hydrogen concentration detection system 4 detects the hydrogen concentration in the ash treatment device 3.

[0070] In the ash treatment device 3, the ash (mainly alkaline in composition) is cooled with cooling water W (see FIG. 3 ), which makes the cooling water W alkaline. In particular, when the cooling water W is circulated, the alkalinity of the cooling water W increases. This causes metals (e.g., aluminum) contained in the ash to react with the alkaline cooling water W, generating hydrogen. If the generated hydrogen accumulates, there is a possibility that an explosion will occur due to the accumulated hydrogen.

[0071] Therefore, in the present invention, the hydrogen concentration in the ash treatment device 3 is monitored by the hydrogen concentration detection system 4. More specifically, the hydrogen concentration detection system 4 includes a plurality of hydrogen sensors 41 and a control device 42. In other words, the ash treatment system 1 includes a plurality of hydrogen sensors 41.

[0072] (3-1) Hydrogen Sensor The multiple hydrogen sensors 41 are capable of measuring the hydrogen concentration within the ash treatment device 3. In other words, the hydrogen concentration detection system 4 is capable of measuring the hydrogen concentration at multiple points within the ash treatment device 3. In detail, the multiple hydrogen sensors 41 include multiple upstream hydrogen sensors 41A, 41B, 41C, 41D, multiple downstream hydrogen sensors 41E, 41F, and an inlet hydrogen sensor 41G.

[0073] The upstream hydrogen sensors 41A, 41B are capable of measuring the hydrogen concentration within the dust ash transport path 32. The upstream hydrogen sensors 41A, 41B are arranged apart from each other in the direction in which the dust ash transport path 32 extends. As a result, the upstream hydrogen sensors 41A, 41B continuously measure the hydrogen concentration at two separate locations within the dust ash transport path 32. The number of hydrogen sensors 41 attached to the dust ash transport path 32 is not limited. The number of hydrogen sensors 41 attached to the dust ash transport path 32 may be one, or may be three or more.

[0074] The upstream hydrogen sensors 41C, 41D are capable of measuring the hydrogen concentration within the boiler adhesion ash transport path 33. The upstream hydrogen sensors 41C, 41D are arranged apart from each other in the direction in which the boiler adhesion ash transport path 33 extends. As a result, the upstream hydrogen sensors 41C, 41D continuously measure the hydrogen concentration at two separate locations within the boiler adhesion ash transport path 33. The number of hydrogen sensors 41 attached to the boiler adhesion ash transport path 33 is not limited. The number of hydrogen sensors 41 attached to the boiler adhesion ash transport path 33 may be one, or may be three or more.

[0075] The downstream hydrogen sensors 41E, 41F are capable of measuring the hydrogen concentration within the downstream transport path 34. The downstream hydrogen sensors 41E, 41F are positioned apart from each other in the direction in which the downstream transport path 34 extends. As a result, the downstream hydrogen sensors 41E, 41F continuously measure the hydrogen concentration at two separate locations within the downstream transport path 34. The number of hydrogen sensors 41 attached to the downstream transport path 34 is not limited. The number of hydrogen sensors 41 attached to the downstream transport path 34 may be one, or may be three or more.

[0076] 3, the receiving port hydrogen sensor 41G is capable of measuring the hydrogen concentration in the receiving port 311A ​​of the ash pusher 31. The receiving port hydrogen sensor 41G continuously measures the hydrogen concentration in the receiving port 311A ​​of the ash pusher 31.

[0077] Each of the multiple hydrogen sensors 41 is preferably a wireless hydrogen detection device. Alternatively, each of the multiple hydrogen sensors 41 may be a wired hydrogen detection device. Generated hydrogen accumulates in unexpected locations within the ash treatment device 3. Therefore, it is preferable to perform multi-point monitoring of hydrogen concentration using small, wireless hydrogen sensors and communication devices that can be easily installed and used anywhere. Multi-point monitoring of hydrogen concentration allows the hydrogen accumulation status and accident risk to be predicted based on the trend in hydrogen concentration at each hydrogen sensor installation location. Furthermore, when an explosion risk is determined to have increased, explosions can be avoided by measures such as promoting ventilation throughout the entire facility or pinpointing and forcing ventilation in areas where the explosion risk has increased. Note that if the hydrogen concentration gradually increases and an explosion risk is determined to have increased, promoting ventilation throughout the facility is preferable. However, if an explosion risk is determined to have increased due to a sudden increase in hydrogen concentration, pinpointing and forcing ventilation (such as air blowing + venting to the atmosphere) in areas where the explosion risk has increased is preferable.

[0078] (3-2) Control Device As shown in FIGS. 2 and 3, the control device 42 is capable of receiving signals from each of the multiple hydrogen sensors 41.

[0079] As shown in Figure 4, the ash treatment system 1 may further include a display device 51, a warning light 52, a fan 53 in the dust ash transport path 32, a fan 54 in the boiler adhesion ash transport path 33, a fan 55 in the downstream transport path 34, a fan 56 in the ash extrusion device 31, and a post-combustion grate drive device 57.

[0080] The display device 51 is disposed, for example, in a control room of the waste incineration facility. The warning light 52 is attached, for example, to the ash pusher 31. The fan 53 is attached to the falling dust ash transport path 32. The fan 54 is attached to the boiler adhesion ash transport path 33. The fan 55 is attached to the downstream transport path 34. The fan 56 is attached to the ash pusher 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.

[0081] The control device 42 controls, by wireless or wired connection, the display device 51, the warning light 52, the fan 53 of the falling dust ash transport path 32, the fan 54 of the boiler adhesion ash transport path 33, the fan 55 of the downstream transport path 34, the fan 56 of the ash pusher 31, the post-combustion grate drive device 57, and the scraper drive device 313. The control device 42 may be integrated with other control devices of the incinerator.

[0082] 5, the control device 42 monitors the hydrogen concentration in the dust ash transport path 32 based on signals from the upstream hydrogen sensors 41A, 41B (see FIG. 2), and when the hydrogen concentration in the dust ash transport path 32 exceeds a threshold value (first threshold value) (S1: YES), the control device 42 performs ventilation processing for the dust ash transport path 32 (S2). In the ventilation processing for the dust ash transport path 32, the control device 42 operates a fan 53 (see FIG. 4) to ventilate the dust ash transport path 32.

[0083] In addition, in parallel with the processing for the dust ash transport path 32, the control device 42 also monitors the hydrogen concentration inside the boiler adhesion ash transport path 33 and the downstream transport path 34, and performs ventilation processing if the hydrogen concentration exceeds a threshold value.

[0084] In detail, the control device 42 monitors the hydrogen concentration in the boiler adhesion ash transport path 33 based on signals from the upstream hydrogen sensors 41C, 41D (see FIG. 2), and when the hydrogen concentration in the boiler adhesion ash transport path 33 exceeds a threshold value (second threshold value), the control device 42 performs a ventilation process for the boiler adhesion ash transport path 33. In the ventilation process for the boiler adhesion ash transport path 33, the control device 42 operates a fan 54 (see FIG. 4) to ventilate the boiler adhesion ash transport 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.

[0085] The control device 42 also monitors the hydrogen concentration in the downstream transfer path 34 based on signals from the downstream hydrogen sensors 41E, 41F (see FIG. 2 ). When the hydrogen concentration in the downstream transfer path 34 exceeds a threshold value (third threshold value), the control device 42 performs ventilation of the downstream transfer path 34. In the ventilation of the downstream transfer path 34, the control device 42 activates a fan 55 (see FIG. 4 ) to ventilate the downstream transfer path 34. The third threshold value can be set independently of the first and second threshold values. The third threshold value may be the same as or different from the first and second threshold values. The third threshold value is preferably higher than the first and second threshold values.

[0086] Then, when the hydrogen concentration becomes equal to or lower than the safe value (S1: NO, S3: YES, S4: YES), the control device 42 stops the ventilation process (S5).

[0087] As shown in FIG. 6, the control device 42 monitors the hydrogen concentration in the receiving port 311A ​​of the ash extrusion device 31 based on a signal from the receiving port hydrogen sensor 41G (see FIG. 3). If the hydrogen concentration detected by the receiving port hydrogen sensor 41G exceeds a threshold value (fourth threshold value) (S11: YES), the control device 42 executes a warning process (S12). The fourth threshold value can be set independently of the first, second, and third threshold values. The fourth threshold value may be the same as or different from the first, second, and third threshold values. The fourth threshold value is preferably higher than the first, second, and third threshold values.

[0088] Here, if the hydrogen concentration detected by the receiving port hydrogen sensor 41G exceeds a threshold value (fourth threshold value), and if it adheres to and grows on the inner wall of the chute 2 (see Figure 3), a state called a "bridge" will occur in which the inside of the chute 2 is blocked.As a result of the chute 2 being blocked, it is possible that the hydrogen in the ash extrusion device 31, which would have escaped to the incinerator side if the chute 2 were not blocked, will remain near the receiving port 311A.

[0089] Therefore, in the warning process, the control device 42, for example, displays on the display device 51 (see Figure 4) that the chute 2 may be blocked, and activates the warning light 52 (see Figure 4) to warn of the blockage of the chute 2.

[0090] Furthermore, if the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds the threshold value, it is possible that the alkalinity of the cooling water has become excessively strong, causing an increase in the amount of hydrogen generated.

[0091] Therefore, the control device 42 may execute a water injection process to add 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 thresholds and safety values ​​different from those used in the warning process (S12).

[0092] When the hydrogen concentration becomes equal to or lower than the safe value (S11: NO, S13: YES, S14: YES), the control device 42 cancels the warning (S15).

[0093] The hydrogen concentration distribution at 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.

[0094] 2. Effects and Advantages (1) According to the ash treatment system 1 and the hydrogen concentration detection system 4, as shown in FIG. 2, the hydrogen concentration at multiple points within the ash treatment device 3 can be monitored by multiple hydrogen sensors 41.

[0095] Therefore, the risk of an explosion caused by hydrogen gas can be evaluated based on the hydrogen concentration measured by the hydrogen sensor 41, and processing can be performed to avoid the explosion.

[0096] As a result, the occurrence of a hydrogen explosion in the ash treatment device 3 can be avoided.

[0097] (2) According to the ash treatment system 1 and the hydrogen concentration detection system 4, as shown in Fig. 2, the ash treatment device 3 includes an ash push-out device 31, and an upstream transport path that includes a dust ash transport path 32 and a boiler-adhered ash transport path 33 connected to the ash push-out device 31. The upstream hydrogen sensors 41A and 41B can measure the hydrogen concentration in the dust ash transport path 32. The upstream hydrogen sensors 41C and 41D can measure the hydrogen concentration in the boiler-adhered ash transport path 33.

[0098] As a result, even if hydrogen gas generated in the ash extrusion device 31 flows into the ash transport path 32, the increase in hydrogen concentration in the ash transport path 32 can be detected by the upstream hydrogen sensors 41A, 41B.

[0099] Furthermore, even if hydrogen gas generated in the ash push-out device 31 flows into the boiler-adhered ash transport path 33, the increase in hydrogen concentration in the boiler-adhered ash transport path 33 can be detected by the upstream hydrogen sensors 41C, 41D.

[0100] As a result, processing can be carried out in the dust ash transport path 32 and the boiler adhesion ash transport path 33 to avoid explosions.

[0101] (3) According to the ash treatment system 1 and the hydrogen concentration detection system 4, as shown in FIG. 2, the ash treatment device 3 includes a downstream conveying path 34 that conveys the ash pushed out from the ash pusher 31. The downstream hydrogen sensors 41E and 41F are capable of measuring the hydrogen concentration in the downstream conveying path 34.

[0102] This allows the downstream hydrogen sensors 41E and 41F to monitor hydrogen generated from the wet ash in the downstream transport path 34.

[0103] In addition, if the hydrogen concentration in the downstream conveying path 34 increases excessively, for example, when hydrogen gas generated in the ash extrusion device 31 flows into the downstream conveying path 34, processing can be carried out to avoid explosion, just as with the upstream conveying paths (fall ash conveying path 32 and boiler-adhered ash conveying path 33).

[0104] (4) According to the ash treatment system 1 and the hydrogen concentration detection system 4, as shown in Figures 2 and 5, when the hydrogen concentration in the dust ash transport path 32 exceeds a threshold value (S1: YES), the control device 42 performs ventilation processing of the dust ash transport path 32 (S2).

[0105] Therefore, if the hydrogen concentration measured by the upstream hydrogen sensors 41A, 41B exceeds the threshold value and the risk of an explosion due to hydrogen gas in the dust ash transport path 32 increases, the dust ash transport path 32 can be ventilated to avoid the explosion.

[0106] Similarly, when the hydrogen concentration in the boiler adhering ash conveying path 33 exceeds the threshold value (S1: YES), the control device 42 executes ventilation processing of the boiler adhering ash conveying path 33 (S2).

[0107] Therefore, if the hydrogen concentration measured by the upstream hydrogen sensors 41C, 41D exceeds the threshold value and the risk of an explosion due to hydrogen gas in the boiler-adhered ash transport path 33 increases, the boiler-adhered ash transport path 33 can be ventilated to avoid the explosion.

[0108] (5) According to the ash treatment system 1 and the hydrogen concentration detection system 4, as shown in Figures 2 and 5, when the hydrogen concentration in the downstream conveying path 34 exceeds a threshold value (S1: YES), the control device 42 performs ventilation treatment of the downstream conveying path 34 (S2).

[0109] Therefore, if the hydrogen concentration measured by the downstream hydrogen sensors 41E, 41F exceeds the threshold value and the risk of an explosion due to hydrogen gas in the downstream conveying path 34 increases, the downstream conveying path 34 can be ventilated to avoid the explosion.

[0110] (6) In the ash treatment system 1 and the hydrogen concentration detection system 4, each hydrogen sensor 41 is a wireless hydrogen detection device. As shown in Figure 2, the upstream hydrogen sensors 41A and 41B continuously measure the hydrogen concentration at two separate locations within the dust ash transport path 32.

[0111] This allows the flow of hydrogen gas within the dust ash transport path 32 to be estimated.

[0112] The upstream hydrogen sensors 41C and 41D continuously measure the hydrogen concentrations at two locations separated from each other within the boiler adhering ash transport path 33.

[0113] This allows the flow of hydrogen gas within the boiler ash transport path 33 to be estimated.

[0114] (7) According to the ash treatment system 1 and the hydrogen concentration detection system 4, as shown in FIG. 2, the downstream hydrogen sensors 41E and 41F continuously measure the hydrogen concentration at two locations separated from each other within the downstream conveying path 34.

[0115] This allows the flow of hydrogen gas within the downstream transfer path 34 to be estimated.

[0116] (8) According to the ash treatment system 1 and the hydrogen concentration detection system 4, as shown in FIG. 3, the receiving port hydrogen sensor 41G can measure the hydrogen concentration in the receiving port 311A ​​of the ash pusher 31.

[0117] Therefore, the inlet hydrogen sensor 41G can monitor the hydrogen concentration in the ash extrusion device 31, which is assumed to be the main source of hydrogen gas.

[0118] 3. Modifications Modifications will be described below. In the modifications, the same components as those in the above-described embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0119] (1) The ash treatment device 3 does not need to have the boiler-adhered ash transport path 33. The boiler-adhered ash (fly ash) may be transported to a fly ash treatment facility separate from the ash treatment device 3 and solidified there.

[0120] (2) As shown in Fig. 7, the ash pusher 31 may be of a sprinkler type. Specifically, the ash pusher 31 sprinkles cooling water onto the ash in the cooling water tank 311 without immersing the ash in the cooling water tank 311. The ash pusher 31 has a nozzle 61 as an example of a sprinkler means. The nozzle 61 sprinkles water onto the ash in the cooling water tank 311 to cool it. The cooled ash is pushed by a scraper 312 and discharged from a discharge port 311B.

[0121] (3) The ash processing device 3 may be provided with a water-cooled conveyor 71 instead of the ash pusher 31. The water-cooled conveyor 71 may be a water-sealed type, as shown in Fig. 8, in which the ash is cooled by immersing it in cooling water W stored in the water-cooled conveyor 71, or a water-spray type, as shown in Fig. 9, in which the ash is cooled by spraying water from nozzles 72.

[0122] The water-cooled conveyor 71 cools the ash with water and transports the cooled ash. A drag chain conveyor is arranged inside the water-cooled conveyor 71. The ash in the water-cooled conveyor 71 is transported by the drag chain conveyor toward the ash pit B (see Figure 1).

[0123] The receiving port hydrogen sensor 41G may be capable of measuring the hydrogen concentration within the receiving port 311A ​​of the water-cooled conveyor 71.

[0124] According to this modified example, a water-cooled conveyor 71 is provided instead of the ash extrusion device 31, and when the ash is cooled using the water-cooled conveyor 71, the receiving port hydrogen sensor 41G can be used to monitor the hydrogen concentration within the water-cooled conveyor 71, which is assumed to be the main source of hydrogen gas.

[0125] (4) The water-cooled conveyor 71 may be continuous with the dust ash transport path 32 (see FIG. 2).

[0126] (5) When the hydrogen concentration detected by the inlet hydrogen sensor 41G (see Figure 3) exceeds a threshold value, the control device 42 may control the post-combustion grate driving device 57 to adjust the driving speed of the post-combustion grate A13 (see Figure 2), as shown in Figure 4.

[0127] According to this modification, the driving speed of the post-combustion grate A13 can be adjusted based on the hydrogen concentration detected by the inlet hydrogen sensor 41G so that the amount of hydrogen gas generated does not increase excessively.

[0128] In detail, when the hydrogen concentration detected by the inlet hydrogen sensor 41G exceeds a threshold value, the control device 42 controls the post-combustion grate driving device 57 to slow down the driving speed of the post-combustion grate A13.

[0129] By slowing down the driving speed of the post-combustion grate A13, the amount of incineration 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.

[0130] (6) When the hydrogen concentration detected by the inlet hydrogen sensor 41G (see Figure 3) exceeds a threshold value, the control device 42 may control the scraper driving device 313 to adjust the driving timing of the scraper 312 (see Figure 3).

[0131] According to this modification, the drive timing of the scraper 312 can be adjusted based on the hydrogen concentration detected by the inlet hydrogen sensor 41G so that the amount of hydrogen gas generated does not increase excessively.

[0132] More 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 drive timing of the scraper 312 so that the drive interval of the scraper 312 is longer than the set value. The control device 42 also controls the scraper driving device 313 to adjust the drive timing of the scraper 312 so that the drive timing of the scraper 312 is delayed relative to the drive timing of the post-combustion grate driving device 57.

[0133] (7) The same effects as those of the embodiment can be obtained in the modified examples (1) to (6). Note that the above invention is provided as an exemplary embodiment of the present invention, but this is merely an example and should not be interpreted as limiting. Modifications of the present invention that are obvious to those skilled in the art are included in the scope of the claims below.

[0134] The ash treatment system of the present invention and the hydrogen concentration detection system of the present invention can be used for ash treatment at waste incineration facilities.

[0135] 1 Ash treatment system 3 Ash treatment device 31 Ash extrusion device 311 Cooling water tank 311A ​​Receiving port 32 Falling dust ash transport path (an example of an upstream transport path) 33 Boiler adhesion ash transport path (an example of an upstream transport path) 34 Downstream transport path 4 Hydrogen concentration detection system 41 Hydrogen sensors 41A to 41D Upstream hydrogen sensors 41E, 41F Downstream hydrogen sensors 41G Receiving port hydrogen sensor 42 Control device 61 Nozzle (an example of a water sprinkling means) 71 Water-cooled conveyor A Incinerator

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; and a hydrogen sensor capable of measuring the hydrogen concentration in the ash treatment device.

2. The ash treatment device includes: an ash extrusion device that cools the ash with water and extrudes the cooled ash; and an upstream conveyance path connected to the ash extrusion device for conveying the ash. The hydrogen sensor is an upstream hydrogen sensor capable of measuring the hydrogen concentration in the upstream conveyance path. The ash treatment system according to claim 1.

3. The upstream conveyance path is a fallen ash conveyance path for conveying fallen ash dropped from the incinerator to the ash extrusion device. The ash treatment system according to claim 2.

4. The upstream conveyance path is a boiler-attached ash conveyance path for conveying fly ash attached to a boiler to the ash extrusion device. The ash treatment system according to claim 2.

5. The ash treatment device includes: an ash extrusion device that cools the ash with water and extrudes the cooled ash; and a downstream conveyance path for conveying the ash extruded from the ash extrusion device. The hydrogen sensor is a downstream hydrogen sensor capable of measuring the hydrogen concentration in the downstream conveyance path. The ash treatment system according to claim 1.

6. The ash treatment system further includes a control device capable of receiving a signal from the hydrogen sensor. When the hydrogen concentration in the upstream conveyance path exceeds a threshold value, the control device performs a ventilation process of ventilating the inside of the upstream conveyance path. The ash treatment system according to claim 2.

7. The ash treatment system further includes a control device capable of receiving a signal from the hydrogen sensor. When the hydrogen concentration in the downstream conveyance path exceeds a threshold value, the control device performs a ventilation process of ventilating the inside of the downstream conveyance path. The ash treatment system according to claim 5.

8. The hydrogen sensor is a wireless hydrogen detection device. The ash treatment system includes a plurality of the upstream hydrogen sensors. The plurality of upstream hydrogen sensors continuously measure the hydrogen concentrations at a plurality of locations separated from each other in the upstream conveyance path. The ash treatment system according to claim 2.

9. The hydrogen sensor is a wireless hydrogen detection device, the ash treatment system includes a plurality of the downstream hydrogen sensors, and the plurality of the downstream hydrogen sensors continuously measure hydrogen concentrations at a plurality of locations spaced apart from each other within the downstream conveyance path. The ash treatment system according to claim 5.

10. The ash extrusion device has an inlet for receiving the ash, and the ash treatment system further includes an inlet hydrogen sensor capable of measuring the hydrogen concentration within the inlet of the ash extrusion device. The ash treatment system according to claim 2 or claim 5.

11. The ash extrusion device has a cooling water tank for immersing the ash in water for cooling. The ash treatment system according to claim 2 or claim 5.

12. The ash extrusion device has a water spraying means for spraying water on the ash to cool the ash. The ash treatment system according to claim 2 or claim 5.

13. The ash treatment device includes a water-cooled conveyor for cooling the ash with water and conveying the cooled ash, and the hydrogen sensor is capable of measuring the hydrogen concentration within the water-cooled conveyor. The ash treatment system according to claim 1.

14. A hydrogen concentration detection system for detecting the hydrogen concentration within an ash treatment device for treating ash discharged from an incinerator, the system including a hydrogen sensor capable of measuring the hydrogen concentration and a control device capable of receiving a signal from the hydrogen sensor.

15. The ash treatment device includes an ash extrusion device for cooling the ash with water and extruding the cooled ash, and an upstream conveyance path connected to the ash extrusion device for conveying the ash. The hydrogen sensor is an upstream hydrogen sensor capable of measuring the hydrogen concentration within the upstream conveyance path. The hydrogen concentration detection system according to claim 14.

16. The ash treatment device includes an ash extrusion device for cooling the ash with water and extruding the cooled ash, and a downstream conveyance path connected to the ash extrusion device for conveying the ash extruded from the ash extrusion device. The hydrogen sensor is a downstream hydrogen sensor capable of measuring the hydrogen concentration within the downstream conveyance path. The hydrogen concentration detection system according to claim 14.

17. The ash extrusion device has an inlet for receiving the ash, and the hydrogen concentration detection system further includes an inlet hydrogen sensor capable of measuring the hydrogen concentration in the inlet of the ash extrusion device. The hydrogen concentration detection system according to claim 15 or claim 16.

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