Incinerator raw material supply device

Abstract

To provide a raw material supply device for an incinerator capable of supplying a raw material in fixed and small amounts.SOLUTION: A raw material supply device 1 includes a raw material supply part 2, a raw material storage part 3 and a control section 4 for controlling these parts. The raw material supply part 2 includes: a raw material hopper 11 accommodating a raw material 10; and a raw material conveyance mechanism (screw conveyor) 12 provided below the raw material hopper 11. The raw material storage part 3 includes: a chute 21 that causes the raw material 10 to pass from the raw material conveyance mechanism 12 to a raw material input port 31 of an incinerator; weight measurement means 22 for the raw material 10 input to the chute 21; and a double door type flap damper 23 capable of opening / closing an opening part on the raw material input port 31 side of the chute 21. When the weight measurement means 22 detects a preset range of weight, the control section 4 performs control to open the flap damper 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a raw material supply device that supplies raw materials (materials to be incinerated) to an incinerator such as a fluidized bed incinerator. [Background technology]

[0002] Fluidized-bed furnaces are known as one type of incineration equipment used to incinerate general garbage and industrial waste, or to detoxify the ash generated by such incineration. Fluidized-bed furnaces have a fluidized bed in the hearth where a fluidizing medium such as silica sand is piled up, and the fluidized sand is heated by blowing up gas such as air from the hearth into the fluidized bed. The raw material (waste) fed into the fluidized-bed furnace is mixed with the high-temperature fluidized sand, agitated, dried, pyrolyzed, and combusted.

[0003] A method of supplying raw materials to the combustion chamber in a fluidized bed furnace using a pusher device is known. For example, a supply control device that injects a predetermined amount of humidified water when supplying ash to an ash hopper, and a device that quantitatively grasps the state of ash accumulated and stored inside a hopper have been proposed, and these devices are configured to send out ash using a pusher device (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-65334 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-147847 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the pusher device disclosed in the above patent document, the pusher, which is formed with a diameter dimension approximately the same as the inner diameter of the cylinder, expands and contracts within the cylinder, so when supplying ash, the ash pushed out by the pusher may remain at the tip of the cylinder or adhere to the pusher. As a result, the pressure cannot be transmitted within the original expansion and contraction range of the cylinder, and the ash may not be sufficiently discharged.

[0006] Alternatively, it is possible to open and close a slide damper to achieve batch-type fixed-quantity supply, but the problem with conventional slide dampers is that the damper is long and cannot be opened and closed quickly, making it difficult to supply a fixed amount of raw material in small amounts.

[0007] Furthermore, when the damper is opened during raw material supply, a large amount of raw material may be dumped into the combustion chamber in a single mass. This can cause excessive combustion in the combustion chamber, resulting in an unstable environment inside the combustion chamber, with positive pressure inside the furnace, oxygen deficiency, and increased exhaust gas load, which can place a heavy burden on downstream exhaust gas treatment equipment.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a raw material supply device for an incinerator that is capable of supplying raw materials in fixed amounts and in small amounts. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides an apparatus for supplying raw materials to an incinerator, comprising a raw material supply unit, a raw material storage unit, and a control unit for controlling the operations of these units, wherein the raw material supply unit comprises a raw material hopper for storing the raw material, and a raw material conveying mechanism provided below the raw material hopper, and the raw material storage unit comprises a chute for passing the raw material between the raw material conveying mechanism and the raw material inlet of the incinerator, a means for measuring the weight of the raw material introduced into the chute, and a double-door flap damper that can open and close the opening of the chute on the raw material inlet side, and the control unit comprises: When metering in the raw material storage section is started, the supply of raw material is started, The present invention provides a raw material supply device for an incinerator, characterized in that when the weight measuring means detects a weight within a preset range, the flap damper is controlled to open.

[0010] It is preferable that the control unit controls the flap damper to close when the inside of the furnace body of the incinerator becomes positive pressure.

[0011] The control unit may also control the conveying speed of the material conveying mechanism in accordance with the components of exhaust gas from the incinerator.

[0012] The control unit may control the material conveying mechanism to stop when the inside of the furnace body of the incinerator becomes positive pressure.

[0013] The raw material transport mechanism may be a screw conveyor, and the control unit may control the rotation speed of the screw conveyor in accordance with the oxygen concentration at the outlet of a boiler provided downstream of the combustion furnace.

[0014] The incinerator may be a fluidized bed furnace. [Effects of the Invention]

[0015] According to the present invention, raw materials can be supplied to an incinerator in a fixed amount and in small amounts. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing an example of a raw material supply device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a raw material supply device used as a comparative example in the examples. [Figure 3] 1 is a graph comparing the CO concentration in the exhaust gas of a furnace between an example of the present invention and a comparative example in an example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and redundant description will be omitted.

[0018] Examples of incinerators to which the raw material supply device of the present invention can be applied include stoker furnaces, gasification combustion furnaces, fluidized bed furnaces, and rotary kilns. From the viewpoint of suppressing the generation of unburned gas, application to a fluidized bed furnace is preferred. Therefore, in this embodiment, the incinerator is a fluidized bed furnace. This fluidized bed furnace is a typical example, comprising a substantially cylindrical furnace body and a hearth that covers an opening at the bottom of the furnace body. The interior space of the furnace body includes a primary combustion chamber at the bottom, which burns the material to be incinerated using coke or other fuel, and a secondary combustion chamber at the top, which burns the exhaust gas generated by the primary combustion of the material to be incinerated. Granular fluidized sand, such as silica sand, is deposited at the bottom of the primary combustion chamber, forming a fluidized bed in which the material to be incinerated is agitated and burned. The hearth is provided with a fluidizing gas supply port that supplies a fluidizing gas to the primary combustion chamber to blow up and fluidize the fluidized sand. By discharging the fluidizing gas upward, the fluidized sand in the primary combustion chamber is blown up, agitated, and fluidized, forming a fluidized bed.

[0019] The furnace body of the fluidized bed furnace is provided with a raw material inlet 31 for introducing raw materials (material to be incinerated) into the primary combustion chamber, and above the raw material inlet 31, a raw material supply device 1 according to an embodiment of the present invention is disposed.

[0020] 1 shows an example of a raw material supplying device 1 according to this embodiment. The raw material supplying device 1 has a raw material supplying unit 2, a raw material storage unit 3, and a control unit 4 that controls the operations of these units.

[0021] The raw material supply unit 2 is a mechanism for supplying raw material 10 to the raw material storage unit 3. It includes a raw material hopper 11 that accommodates the raw material 10 and a raw material conveying mechanism located below the raw material hopper 11. A bridge breaker 13 is provided on the side of the raw material hopper 11 depending on the type and shape of the raw material. In this embodiment, the raw material conveying mechanism is a screw conveyor 12 located below the raw material hopper 11. The screw conveyor 12 is driven by a motor and has an adjustable rotational speed, allowing for adjustment of the supply amount and conveying speed of the raw material 10. The rotational speed of the screw conveyor 12 can be adjusted manually. However, if, for example, the quality of the raw material 10 is not uniform and frequent adjustment is required, it is preferable to automatically control the speed using PID feedback or other methods using the control unit 4 in response to the components of the exhaust gas from the furnace or, for example, the oxygen concentration at the outlet of a boiler located downstream of the furnace. It is also preferable for the speed to be automatically stopped when positive pressure is reached inside the furnace. Furthermore, the screw conveyor may be switchable between manual and automatic modes.

[0022] The raw material storage section 3 includes a chute 21 connecting the screw conveyor 12 and the raw material inlet 31 of the fluidized-bed furnace, a weighing scale 22 for measuring the weight of the raw material 10 introduced into the chute 21, and a double-door flap damper 23 that can open and close the opening on the raw material inlet 31 side near the tip of the chute 21. The raw material 10 transported by the screw conveyor 12 passes through the chute 21 and is supplied into the furnace. The flap damper 23 is closed when the furnace starts or stops operating, or during an emergency shutdown, thereby isolating the inside of the furnace from the outside, maintaining an airtight seal within the furnace, and preventing a drop in temperature within the furnace. The weight of the raw material piled up on the closed flap damper 23 is measured by the weighing scale 22, and the control unit 4 controls the flap damper 23 to open when a predetermined weight of raw material has been accumulated. It is preferable that the raw material storage section 3 and the raw material supply section 2, and the raw material storage section 3 and the raw material inlet 31 of the furnace are connected by expansion joints 24.

[0023] The furnace usually has a pressure measuring means inside, and in this embodiment, when the pressure inside the furnace is negative, for example, -0.25 kPa or less, it is judged to be normal, and when the pressure is 0 kPa or more, it is judged to be abnormal.

[0024] In this raw material supply device 1, the raw material supply unit 2 starts supplying raw materials 10 when weighing in the raw material storage unit 3 begins, and raw materials 10 are supplied from the raw material hopper 11 via the screw conveyor 12. When the weighing result in the raw material storage unit 3 reaches a predetermined weight, the raw material supply unit 2 stops supplying raw materials 10. The supply of raw materials 10 also stops when the furnace interior becomes positive pressure. The flap damper 23 in the raw material storage unit 3 is closed when weighing begins and opens when the supplied raw materials 10 reach a predetermined weight. When the combustion chamber in the furnace becomes positive pressure, it quickly closes. Then, when the combustion chamber in the furnace returns to normal, i.e., when the pressure in the combustion chamber becomes -0.25 kPa or less, the raw material supply unit 2 resumes supplying raw materials 10, and raw materials 10 are supplied from the raw material hopper 11 via the screw conveyor 12. Weighing in the raw material storage unit 3 also resumes.

[0025] In this way, the flap damper 23 is controlled to open and close within a preset weight range, allowing for constant and small supply of raw materials regardless of their size. This allows for accurate prediction of the amount of raw materials 10 (combustion material) to be supplied into the furnace, making it possible to appropriately control the secondary combustion chamber of the furnace and maintain stable combustion while avoiding incomplete combustion.

[0026] While the preferred embodiments of the present invention have been described above, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas described in the claims, and it is understood that these also fall within the technical scope of the present invention. [Example]

[0027] As an example of the present invention, a flap damper 23 was provided in the raw material storage section 3 as shown in Figure 1, and when the raw material 10 reached a predetermined weight, the flap damper 23 was opened to supply the raw material 10 into the fluidized bed furnace. The flap damper 23 of the present invention has an average cycle time of 8 seconds, a minimum input amount of 16 kg, and a maximum input volume of 0.08 m. 3 , the average density was 0.2.

[0028] As a result, the actual measured average pressure inside the fluidized bed furnace was stable at -0.26 kPa, with little variation. Furthermore, as shown in Figure 3, the CO concentration in the exhaust gas from the furnace was maintained at around 20 ppm, achieving stable combustion. Furthermore, the amount of raw material 10 adhering to the flap damper 23 was small, requiring only periodic cleaning. There was no measurement error, and the raw material 10 was accurately measured and supplied.

[0029] Therefore, with the supply device of the present invention, the combustion state inside the furnace can be accurately predicted, and the pressure in the combustion chamber inside the furnace is equal to the set value with little variation. Furthermore, in the event of an emergency such as when the pressure inside the furnace becomes positive, the damper can be quickly closed.

[0030] As a comparative example, raw material 10 was supplied by a raw material supply device using a single slide type damper 25 as shown in Figure 2 instead of the flap damper 23. The single slide type damper 25 of the comparative example had an average cycle time of 40 seconds, a minimum input amount of 69 kg, and a maximum input amount of 0.35 m. 3 , the average density was 0.2.

[0031] As a result, the measured average pressure inside the fluidized-bed furnace exceeded 0 kPa after the start of operation and showed large variations. Furthermore, as shown in Figure 3, the CO concentration in the exhaust gas from the furnace reached 80 ppm 45 minutes after the start of operation and fluctuated between an average of 60 and 70 ppm, and smoke leakage also occurred. Furthermore, some of the raw material 10 remained on the sliding damper 25 or got caught in the guide, preventing smooth supply. This jamming caused deformation of the sliding damper 25 and dirt to adhere to the cylinder, resulting in costly repairs. Furthermore, because opening and closing the damper takes time, there is also the problem of a long response time in emergencies such as when the furnace becomes pressurized. [Industrial Applicability]

[0032] The present invention can be applied as a method for supplying various raw materials to combustion furnaces such as stoker furnaces, gasification combustion furnaces, fluidized bed furnaces, and rotary kiln furnaces. [Explanation of symbols]

[0033] 1 Raw material supply device 2 Raw material supply section 3 Raw material storage section 4. Control Unit 10 Raw materials 11 Raw material hopper 12 Screw conveyor 21 shots 22 Weighing scale 23 Flap damper 31 Raw material input port

Claims

1. An apparatus for supplying raw materials to an incinerator, The apparatus has a raw material supply unit, a raw material storage unit, and a control unit for controlling the operations thereof, the raw material supply unit includes a raw material hopper that stores the raw material, and a raw material conveying mechanism provided below the raw material hopper; The raw material storage section includes a chute through which the raw material passes between the raw material conveying mechanism and the raw material inlet of the incinerator, a means for measuring the weight of the raw material introduced into the chute, and a double-door flap damper that can open and close an opening of the chute on the raw material inlet side, The control unit starts the supply of raw materials when weighing in the raw material storage unit begins, and controls the flap damper to open when the weight measuring means detects a weight within a preset range.

2. 2. The raw material supply device for an incinerator according to claim 1, wherein the control unit controls the flap damper to close when a positive pressure is created inside the furnace body of the incinerator.

3. 3. The incinerator raw material supply device according to claim 1, wherein the control unit controls the conveying speed of the raw material conveying mechanism in accordance with the components of the exhaust gas from the incinerator.

4. The raw material supply device for an incinerator according to any one of claims 1 to 3, characterized in that the control unit controls the raw material conveying mechanism to stop when the inside of the furnace body of the incinerator becomes positive pressure.

5. 5. The raw material supply device for an incinerator according to claim 1, wherein the raw material transport mechanism is a screw conveyor.

6. 6. The raw material supply device for an incinerator according to claim 5, wherein the control unit controls the rotation speed of the screw conveyor in accordance with the oxygen concentration at the outlet of a boiler provided downstream of the combustion furnace.

7. The raw material supply device for an incinerator according to any one of claims 1 to 6, characterized in that the incinerator is a fluidized bed furnace.

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