JP2014070887A - Fixed-bed stoker furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixed-bed stoker furnace which has a fixed grate, can be miniaturized and can continuously combust waste having a high ash content.SOLUTION: A fixed-bed stoker furnace 1 with a fixed grate 2 comprises: a drive section 4 arranged outside a furnace; combustion acceleration rods 5 which are driven by and connected to the drive section 4, extend from a front wall 3a of the furnace 3, and move back and forth in a longitudinal direction on the grate 2; and an ash chute 14 which is arranged at a rear end section of the grate 2. The fixed-bed stoker furnace 1 may additionally have: combustion acceleration rods which extend from at least either side walls of the furnace and move back and forth in a lateral direction on the grate and combustion acceleration rods which extend from a rear wall of the furnace and move back and forth in the longitudinal direction on the grate.

Description

  The present invention relates to a stoker-type incinerator, and more particularly to a fixed-bed stoker furnace having a fixed grate (stoker).

  Conventionally, stoker-type incinerators are widely known in the field of waste treatment. In an incinerator that burns things that are miscellaneous, rich in moisture such as waste, and hard to burn, fixed grate and movable grate are arranged alternately, and the movable grate slides back and forth, A stoker-type incinerator that combusts waste by conveying it while stirring and reversing from upstream to downstream is generally used (Non-patent Document 1, etc.).

  A stoker-type combustion furnace equipped with such a movable grate has the merit that it can be stably incinerated while agitating and mixing various and difficult-to-burn waste. On the other hand, the structure is large and the equipment is large, and the grate is burned and worn. Therefore, there is a demerit that failure is likely to occur or the replacement frequency is increased.

  On the other hand, a fixed-bed stoker furnace in which the grate does not move is also known. Fixed-floor stoker furnaces have features such as a simple structure because the grate does not slide, and are mainly used for stable combustion of solid fuel and waste with low ash content (1-5%). The If there is little ash content, ash will be deposited little by little on a grate, and waste can be burned continuously over a long period of time. Therefore, even if the grate does not carry, it can be operated if the ash on the grate is discharged by, for example, steam spraying once or twice a day.

  Conversely, if there is a lot of ash (approximately 5% or more), if the incineration is continued in the fixed-bed stoker furnace, the grate will not move, so the ash layer on the grate will become thicker, Residual ash tends to become clinker-like, and combustion of waste is hindered by obstructing ventilation of combustion air from the bottom of the grate. As a result, the waste input due to combustion inhibition does not burn out and the amount of unburned material increases, and when a clinker-like material is generated on the grate, it cannot be discharged by steam spraying or the like.

  For this reason, fixed-bed stoker furnaces are rarely used in the field of waste treatment centered on the current continuous operation.

Takuma Environmental Technology Study Group, “Incineration Technology Picture and Basic Terms”, revised supplement, Ohm Co., Ltd., August 25, 2003, p. 132-133

  However, in order to quickly process a large amount of waste generated during a sudden natural disaster such as the Great East Japan Earthquake, an incinerator with a simple structure that does not drive the grate itself and minimizes the frequency of failure is necessary. It becomes.

  Accordingly, the main object of the present invention is to provide a fixed-bed stoker furnace that does not drive the grate itself, can be miniaturized, and can be continuously incinerated even with waste containing a large amount of ash.

  In order to achieve the above object, a fixed-bed stoker furnace according to the present invention is a fixed-bed stoker furnace having a fixed grate, which is driven and connected to a driving unit disposed outside the furnace and the driving unit. A combustion promoting rod extending from the front wall of the furnace and moving back and forth in the front-rear direction on the grate, and an ash chute disposed at the rear end of the grate.

  The fixed-bed stoker furnace according to the present invention preferably further includes a combustion promoting rod that extends from at least one of the left and right side walls of the furnace and moves forward and backward in the left-right direction on the grate.

  The fixed bed stoker furnace according to the present invention preferably further includes a combustion promoting rod that extends from the rear wall of the furnace and moves forward and backward in the front-rear direction on the grate.

  Moreover, it is preferable that the operation frequency of the combustion promoting rod is adjustable.

  Moreover, it is preferable that the stroke of the combustion promoting rod is adjustable.

  It is preferable that a water-cooled tube is fixed in contact with the back surface of the grate.

  The combustion promoting rod is preferably a water-cooled type in which cooling water is circulated.

  According to the present invention, the combustion promoting rod that moves forward and backward in the furnace by the driving unit outside the furnace breaks down the waste supplied on the fixed grate to promote combustion, and gradually Push to the side to discharge. Therefore, it is possible to transport the waste to the ash chute while stirring while minimizing the trouble by preventing the grate itself from moving and making it a simple structure. Can be stably burned, and continuous operation is also possible.

It is a vertical side view which shows schematic structure of one Embodiment of the fixed bed type stoker furnace which concerns on this invention. It is a side view which shows the example of the grate of the fixed bed type stoker furnace which concerns on this invention. It is a principal part top view which shows typically the operating state of the fixed bed type stoker furnace of FIG. It is a side view which shows the other operating state of FIG. It is a side view which shows the operation state of FIG. It is a principal part vertical side view which shows typically the combustion state of the waste material by the fixed bed type stoker furnace of FIG. It is a principal part vertical side view which shows the other combustion state of FIG. It is explanatory drawing for demonstrating typically the operating method of the fixed bed type stoker furnace of FIG. It is a principal part top view which shows other embodiment of the fixed bed type stoker furnace which concerns on this invention.

  Embodiments of a fixed bed stoker furnace according to the present invention will be described below with reference to FIGS. In addition, the same code | symbol was attached | subjected to the same or similar part through all the figures.

  The fixed floor stoker furnace 1 has a grate 2 fixed and does not have a movable grate. The grate 2 is preferably inclined as a whole in the front-rear direction (left-right direction in FIG. 1; the same applies hereinafter) at a predetermined angle, and is lowered from the front (upstream side) to the rear (downstream side).

  As shown in FIG. 1, the fixed-bed stoker furnace 1 includes a drive unit 4 disposed outside the furnace 3 and a combustion promoting rod 5 that is drivingly connected to the drive unit 4. The combustion promoting rod 5 extends through the front wall 3 a of the furnace 3 into the furnace, and can be moved forward and backward along the fire grate 2 on the fire grate 2 by the drive unit 4. The combustion promoting rod 5 extends through a gap of several millimeters from the grate 2 and is disposed so as not to be in contact with the grate 2 or to apply excessive force to the combustion promoting rod 5. (See FIG. 5).

  The drive unit 4 only needs to have a drive mechanism for moving the combustion promotion rod 5 back and forth. For example, as shown in the example shown in FIG. 1, the endless chain 4d wound around the sprockets 4a, 4b, and 4c promotes combustion. The rear end portion of the rod 5 is connected and fixed, and the motor 4e that rotationally drives the sprocket 4a is rotated forward and backward to reciprocate the combustion promoting rod 5 in the axial direction, thereby moving forward or backward (ie, moving forward and backward). be able to.

  In the illustrated example, the combustion promoting rod 5 can advance to the vicinity of the center of the grate 2 with the tip of the combustion promoting rod 5 retracting to the vicinity of the front wall 3 a of the furnace 3. The stroke S (see FIG. 4) at which the combustion promoting rod 5 moves forward and backward can be adjusted by comprehensively considering the properties of the waste and the combustion state, but preferably the total length L of the grate 2 (FIG. 4). ) Can be adjusted within a range of 1/4 to 1/2.

  Further, the combustion promoting rod 5 may not always advance and retract during the operation of the furnace, and can advance and retract intermittently at a predetermined time interval. Therefore, the combustion promotion rod 5 can adjust the operation frequency of the advance / retreat according to the property of the waste, and can be advanced / retreated about once every 10 minutes, for example.

  The combustion promoting rod 5 enters the waste accumulated on the grate 2 by the advancing motion, so that the waste can be pierced, the waste can be pushed through, or the waste can be gradually pushed out. If it is important to break down the lump of waste, a bowl-shaped hardware is attached to the tip of the combustion promoting rod 5, and if importance is placed on the conveyance performance of the incinerated material after burning the waste, the bowl-shaped hardware is burned. Various shapes of hardware can be attached by welding or other methods depending on the properties of the waste, such as attaching to the tip of the promotion rod 5.

  The combustion promoting rod 5 can be formed of a rod-like member that can withstand high temperatures. For example, by forming the tip of a metal pipe with a cap having a shape effective for discharging ash and promoting combustion, an extrusion and stirring effect can be obtained. Can be increased. Further, as shown in FIG. 3, it is preferable that a plurality of combustion promoting rods 5 are arranged in parallel at an appropriate pitch. In addition, since the combustion promoting rod 5 enters the high-temperature combustion zone, it is preferable that the combustion promoting rod 5 is water-cooled by circulating cooling water therein. A water supply / drain pipe (not shown) that supplies cooling water to the inside of the combustion promoting rod 5 and discharges it from the inside may be connected to the outside of the furnace of the combustion promoting rod 5.

  In the furnace 3, similarly to the conventional stoker furnace, a primary combustion chamber 6 immediately above the grate 2 and a secondary combustion chamber 7 above the primary combustion chamber 6 are provided. A wind box 8 is provided below the grate 2, combustion primary air A <b> 1 is supplied from the forced blower 9 to the wind box 8, and the primary air A <b> 1 supplied to the wind box 8 passes through a gap in the grate 2. Supplied to the waste on the grate 2. Further, the secondary air A2 is supplied from the secondary blower 10 to the upper part of the primary combustion chamber 6 to completely burn the unburned gas. The secondary combustion exhaust gas G is sent to a gas cooling chamber outside the figure. Although not shown in the figure, the primary combustion chamber 6 is provided with a burner for igniting or for promoting combustion according to the quality of dust.

  The waste is transported from the waste hopper 11 by the waste input conveyor 12 and input to the grate 2 in the furnace 3 through the waste chute 13. The waste chute 13 is preferably arranged so as to throw the waste in front of the grate 2 (upstream side), that is, in the vicinity of the retracted position of the tip of the combustion promoting rod 5.

  An ash chute 14 is disposed at the rear end (downstream end) of the grate 2. The ash dropped from the ash chute 14 is carried out by the ash conveyor 15. Although not shown in the figure, a fall ash conveyor for receiving and transporting and discharging the fallen ash that falls from the gap of the grate 2 can also be provided.

  As shown in FIG. 2, the grate 2 can have a water cooling structure by bringing a water cooling pipe 16 into close contact with the back surface (lower surface). In waste incinerators, because the properties of waste change drastically, it is often attempted to extend the life of the stoker by using a water-cooled stalker structure, but in the case of a movable grate, a complicated mechanism is used in the water supply section to cool the water. (For example, a swivel joint) is required. On the other hand, in a fixed-floor stalker, the water grate can be cooled by simply bringing the water-cooled pipe and the immovable grate 2 into close contact with each other, so that a structure that prevents damage to the stalker can be easily constructed. In addition, the cooling effect by water cooling suppresses the generation of clinker on the grate, and the clinker removal work is reduced or almost eliminated.

  According to the fixed bed stoker furnace having the above-described configuration, as shown in FIGS. 3 to 5, the combustion promoting rod 5 repeats advancing and retreating in the front-rear direction (the direction of the chain line arrow FR in FIG. 3). The combustion promoting rod 5 is pierced into the mountain-shaped waste W thrown into the front of the grate 2 and piled up, and the operation of breaking is repeated to stir the waste W. Further, the combustion promoting rod 5 pierces the waste W, so that the waste lump is gradually conveyed to the rear (downstream side) of the grate 2. 3 and 5, a short arrow indicated by a solid line at the tip of the combustion promoting rod schematically shows the movement of the waste W.

  In the combustion of solid matter, if the waste during combustion does not move, the combustion proceeds only at the site that comes into contact with air. With reference to the schematic diagram of FIG. 6, this “part in contact with air” is limited to the vicinity of the passage path of the primary air A <b> 1 of the waste W or the surface portion of the waste W, which is indicated by mesh hatching. Further, since the portion where the combustion has progressed is ashed, the combustion air is blocked, and the combustion does not sufficiently proceed to the inside of the waste W.

  On the other hand, as schematically shown in FIG. 7, the combustion promoting rod 5 makes a hole in the pile of the waste W and breaks down, so that the portion where the combustion has not sufficiently progressed inside the waste is newly added. By being exposed to air, the effect of promoting combustion is obtained.

  Further, as schematically shown in FIG. 8, the waste W is pushed backward (downstream) by a stroke by the combustion promoting rod 5 when combustion progresses to some extent. Then, the waste W is newly introduced into the upstream side and the unburned waste W1 pushed out is further combusted, and finally completely ashed into ash W2 and discharged from the ash chute 14. By repeating such steps (see the shaded arrows in FIG. 8), a continuous operation comparable to that of a conventional stoker furnace having a movable grate can be achieved. In addition, by enabling continuous operation, the number of startups of the furnace can be reduced, and the consumption of kerosene can be reduced accordingly.

  Further, since the movable grate is not provided, the failure occurrence rate is lower than that of the stalker provided with the movable grate, and the maintenance is minimized.

  In the above-described embodiment, only the combustion promoting rod 5 disposed so as to break down waste from the front wall 3a of the primary combustion chamber toward the rear wall 3d of the primary combustion chamber has been described as the combustion promoting rod. Depending on the scale of the furnace, as shown in FIG. 9, it extends from the left and right side walls 3b, 3c of the furnace and moves forward and backward in the left-right direction (in the direction of the arrow RL in FIG. 9) to stab waste from the left and right. A second combustion promotion rod 17 may be provided, or a third combustion promotion rod that extends from the rear wall 3d of the furnace 3 and advances and retreats in the front-rear direction to stab waste from the rear wall 3d of the furnace 3. A rod 18 can also be provided. Although a drive unit for driving the second combustion promotion rod 17 and a drive unit for driving the third combustion promotion rod 18 are not shown, an apparatus similar to the drive unit 4 of the combustion promotion rod 5 is used in the furnace. It arrange | positions outside and is drive-coupled with each combustion promotion rod 17,18. The second combustion promoting rod 17 may be provided only on either the left or right side wall 3b (3c). Similarly to the combustion promoting rod 5, the second and third combustion promoting rods 17 and 18 can be adjusted in their operating frequencies and strokes.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Fixed bed type stoker furnace 2 Grate 3 Furnace 3a Front wall 3b, 3c Side wall 3d Rear wall 4 Drive part 5 Combustion promotion rod 13 Waste chute 14 Ash chute 16 Water cooling pipe 17 Combustion promotion rod 18 Combustion promotion rod

Claims (7)

A fixed-bed stoker furnace with a fixed grate,
A drive unit disposed outside the furnace;
A combustion promoting rod that is drivingly connected to the drive unit, extends from the front wall of the furnace, and moves forward and backward on the grate in the front-rear direction;
An ash chute disposed at the rear end of the grate;
A fixed-bed stoker furnace characterized by comprising:   The fixed-bed stoker furnace according to claim 1, further comprising a combustion promoting rod extending from at least one of the left and right side walls of the furnace and moving forward and backward in the left-right direction on the grate.   The fixed bed stoker furnace according to claim 1, further comprising a combustion promoting rod extending from a rear wall of the furnace and moving forward and backward in the front-rear direction on the grate.   The fixed-bed stoker furnace according to any one of claims 1 to 3, wherein an operation frequency of the combustion promoting rod is adjustable.   The fixed-bed stoker furnace according to any one of claims 1 to 4, wherein a stroke of the combustion promoting rod is adjustable.   The fixed bed stoker furnace according to any one of claims 1 to 5, wherein a water-cooled tube is fixed in contact with the back surface of the grate.   The fixed bed stoker furnace according to any one of claims 1 to 6, wherein the combustion promoting rod is of a water cooling type in which cooling water is circulated therein.