CN109937328B

CN109937328B - Mechanical grate furnace for burning incinerated substance

Info

Publication number: CN109937328B
Application number: CN201880001833.6A
Authority: CN
Inventors: 泽本嘉正; 佐藤淳
Original assignee: Mitsubishi Heavy Industries Environmental and Chemical Engineering Co Ltd
Current assignee: Mitsubishi Heavy Industries Environmental and Chemical Engineering Co Ltd
Priority date: 2017-10-17
Filing date: 2018-10-10
Publication date: 2020-05-08
Anticipated expiration: 2038-10-10
Also published as: PL3699490T3; TW201923285A; BR112020007434B1; BR112020007434A2; SG11202000767UA; EP3699490A1; JP6397107B1; MY197928A; WO2019078071A1; PH12020500215A1; JP2019074277A; EP3699490A4; CN109937328A; RU2753563C1; DK3699490T3; EP3699490B1; TWI683977B

Abstract

Provided is a mechanical grate furnace for burning an object to be burned, which supplies the object to be burned from a feeder (4), and performs drying, burning and burning while sequentially conveying the object to be burned in a drying section (11), a burning section (12) and a burning section (13) each having a plurality of fixed grate segments (15) and a plurality of movable grate segments (16), wherein the drying section (11) is disposed obliquely with the downstream side in the conveying direction facing downward, the burning section (12) is connected to the drying section (11) and disposed obliquely with the downstream side in the conveying direction facing upward, and the burning section (13) is connected to the burning section (12) and disposed obliquely with the downstream side in the conveying direction facing upward.

Description

Mechanical grate furnace for burning incinerated substance

Technical Field

The present invention relates to a mechanical grate furnace for burning an object to be incinerated such as garbage. The present application claims priority based on japanese patent application No. 2017-201342, which was filed in japan on 10/17/2017, and the contents of which are incorporated herein by reference.

Background

As an incinerator for incinerating an object to be incinerated such as refuse, there is known a mechanical grate furnace capable of efficiently performing incineration treatment without sorting a large amount of the object to be incinerated. As a mechanical grate furnace, there are known the following mechanical grate furnaces: the mechanical grate furnace has a stepped structure and is provided with a drying section, a combustion section and an ember section so as to exert various functions of drying, combustion and ember.

In order to reliably burn the object to be incinerated, the inclination angle of the grate is studied. As described in patent document 1, for example, there is an inclination angle in which the inclination angle of the grate is inclined such that the downstream side in the conveyance direction of the mounting surface of all the stages of the drying stage, the combustion stage, and the ember stage is directed downward. In the following, for example, a case where the downstream side of the mounting surface of the drying section in the conveying direction is directed downward is simply referred to as a case where the drying section is directed downward (the same applies to the case of the burning section and the ember section).

Further, as described in patent document 2, there are cases where the drying stage is inclined downward and the burning stage and the ember stage are disposed horizontally, as described in patent document 3, there are cases where the drying stage and the burning stage are inclined downward and the downstream side in the conveyance direction of the attachment surface of the ember stage is inclined upward, and there are cases where all the portions are inclined upward as described in patent document 4. For example, a case where the downstream side of the mounting surface of the combustion stage is directed upward in the conveying direction is simply referred to as a case where the combustion stage is directed upward (the same applies to the case of the drying stage and the ember stage).

Prior art documents

Patent document

Patent document 1: japanese laid-open patent publication No. 6-265125

Patent document 2: japanese Kokai publication Hei-6-84140

Patent document 3: japanese examined patent publication No. 57-12053

Patent document 4: japanese laid-open patent publication No. 50-65062

Disclosure of Invention

Problems to be solved by the invention

However, although the mechanical grate furnaces described above can charge the materials to be incinerated in various shapes (materials, shapes, and water contents), it is difficult to burn the materials to be incinerated in any mechanical grate furnace as in the case of materials that slide easily, materials that roll easily such as spheres, and materials that have a high water content (have a large water content).

That is, in the mechanical grate furnaces described in

patent documents

1, 2, and 3, since the drying zone is inclined downward and the combustion zone is inclined downward or horizontally disposed, the material which is easy to slide or the material which is easy to roll is conveyed to the ember zone earlier than the other material to be burned, and therefore, there are the following problems: the incinerated substance is not sufficiently incinerated and is discharged in an unburned state.

In the mechanical grate furnace described in patent document 4, since all the stages of the drying stage, the combustion stage, and the ember stage are inclined upward, the material which is easy to slide, the material which is easy to roll, and the material which is high in water content are accumulated at the bottom of the stage (drop wall) disposed between the feeder and the drying stage and are difficult to be conveyed to the combustion stage, and therefore, there is a problem as follows: sometimes it is necessary to limit the amount of dosing or to temporarily stop dosing.

The invention aims to provide a mechanical grate furnace for burning incineration objects such as garbage, which can continuously feed the incineration objects regardless of the properties of the incineration objects and can completely burn the incineration objects.

Means for solving the problems

According to a first aspect of the present invention, in a mechanical grate furnace for burning an object to be incinerated, such as refuse, in which the object to be incinerated is supplied from a feeder, and the object to be incinerated is dried, burned, and burned while being sequentially conveyed in a drying stage, a combustion stage, and a burning stage, each of which includes a plurality of fixed grate segments and a plurality of movable grate segments, the drying stage is disposed so as to be inclined with a downstream side in the conveying direction thereof directed downward, the combustion stage is connected to the drying stage and is disposed so as to be inclined with a downstream side in the conveying direction thereof directed upward, and the burning stage is connected to the combustion stage and is disposed so as to be inclined with a downstream side in the conveying direction thereof directed upward.

According to this configuration, the drying section is inclined downward, whereby the material to be incinerated of any kind of property can be conveyed to the combustion section without being retained, and the combustion section and the ember section are inclined upward, whereby the material to be incinerated can be sufficiently combusted and conveyed after the combustion section without easily slipping or rolling off.

That is, in the case of an easily slidable material or an easily rollable object to be incinerated, the object is early conveyed to the combustion stage by rolling in the drying stage, and therefore, the object may not be sufficiently dried in the drying stage. However, since the combustion section and the ember section are inclined upward, the material to be incinerated that has fallen down in the drying section is not promptly conveyed by rolling in the combustion section and the ember section, and is inevitably sufficiently dried and incinerated in the combustion section. Since the material to be incinerated having a high water content is dried without being retained in the drying stage and is then transported to the combustion stage, the material to be incinerated is inevitably sufficiently incinerated also in the combustion stage.

This enables the continuous supply of the material to be incinerated regardless of the properties of the material to be incinerated, and enables the complete burning of the material to be incinerated.

In the mechanical grate furnace, an end portion of the ember zone on the downstream side in the conveyance direction may be disposed at substantially the same position as an end portion of the combustion zone on the downstream side in the conveyance direction in the vertical direction, or may be disposed at a position above the end portion of the combustion zone.

According to this configuration, even when the material to be incinerated rolls down in the drying section or the like, the material to be incinerated can be prevented from being discharged from the ember section in a state where the material is not sufficiently burned.

In the mechanical grate furnace, the fixed grate segment and the movable grate segment may be disposed to be inclined such that a downstream side in the conveying direction faces upward with respect to mounting surfaces of the drying section, the combustion section, and the ember section.

According to this configuration, the movable grate segment can be operated to convey the material to be incinerated to the downstream side in the conveying direction while stirring the material to be incinerated on the fixed grate segment.

In the mechanical grate furnace, the drying section, the combustion section, and the ember section may each independently have a driving mechanism for driving the plurality of movable grate segments provided in the drying section, the combustion section, and the ember section, and the driving speeds in the drying section, the combustion section, and the ember section may be set to the same speed or different speeds in at least a part of the drying section, the combustion section, and the ember section.

With this configuration, the transport speed of each stage can be changed according to the properties of the material to be incinerated that is charged.

In the mechanical grate furnace, the combustion section and the ember section may be continuously connected without a stage.

With this configuration, the material to be incinerated can be further continuously incinerated.

In the mechanical grate furnace, at least a part of the plurality of moving grate segments of the drying section may be a grate segment with a protrusion provided at a tip thereof.

According to such a configuration, the agitation effect of the material to be incinerated when the movable grate segment reciprocates can be improved.

In the mechanical grate furnace, at least a part of the plurality of moving grate segments of the combustion section may be a grate segment with a protrusion provided at a tip thereof.

In the mechanical grate furnace, the grate inclination angle of the drying section may be set to an angle between-15 ° and-25 °, and the grate inclination angles of the combustion section and the ember section may be set to an angle between +5 ° and +15 °.

In addition, the grate inclination angle of the drying section may be set to-20 °, and the grate inclination angles of the burning section and the ember section may be set to +10 °.

According to this structure, the necessary grate length can be shortened, and therefore, a mechanical grate furnace which can be reduced in size and cost can be provided.

Effects of the invention

According to the present invention, the material to be incinerated can be continuously fed regardless of the properties of the material to be incinerated, and the material to be incinerated can be completely burned out.

Drawings

Fig. 1 is a schematic configuration diagram of a mechanical grate furnace according to a first embodiment of the present invention.

Fig. 2 is a view illustrating the inclination angle of the grate of the mechanical grate furnace according to the first embodiment of the present invention.

Fig. 3 is a side view illustrating the shape of a grate plate of a mechanical grate furnace according to a first embodiment of the present invention.

Fig. 4 is a graph illustrating a suitable range of grate inclination angles for the drying section between-15 deg. and-25 deg..

Fig. 5 is a graph illustrating a suitable range of grate slope angles for the combustion section between +5 deg. and +15 deg..

Fig. 6 is a graph illustrating the reason why the appropriate range of the grate inclination angle of the combustion zone is set to an angle between +8 ° and +12 ° in consideration of both the drying zone and the combustion zone, and the optimum value is +10 °.

Fig. 7 is a view illustrating the inclination angle of the grate of the mechanical grate furnace according to the second embodiment of the present invention.

Detailed Description

[ first embodiment ]

Hereinafter, a mechanical grate furnace according to a first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The mechanical grate furnace of the present embodiment is a mechanical grate furnace for burning an object to be burned such as garbage, and as shown in fig. 1, includes a hopper 2 for temporarily storing the object to be burned T, an incinerator 3 for burning the object to be burned T, a feeder 4 for supplying the object to be burned T to the incinerator 3, a mechanical grate 5 (including

grate segments

15 and 16 of a drying section 11, a combustion section 12, and an ember section 13) provided on the bottom side of the incinerator 3, and a wind chamber 6 provided below the mechanical grate 5.

The feeder 4 pushes out the objects to be incinerated T, which are continuously supplied to the feeder deck 7 through the hopper 2, into the incinerator 3. The feeder 4 is reciprocated by a predetermined stroke on the feeder deck 7 by a feeder driving device 8.

The plenum 6 supplies primary air from a blower (not shown) to each section of the mechanical grate 5.

The incinerator 3 is disposed above the mechanical grate 5, and has a combustion chamber 9 composed of a primary combustion chamber and a secondary combustion chamber. A blower 10 for supplying secondary air to the combustion chamber 9 is connected to the incinerator 3.

The mechanical grate 5 is a combustion apparatus in which

grate segments

15, 16 are arranged in a step-like manner. The material to be incinerated T is burned on the mechanical grate 5.

Hereinafter, the direction in which the material to be incinerated T is conveyed is referred to as the conveyance direction D. The material to be incinerated T is transported on the mechanical grate 5 in the transport direction D. In fig. 1, 2, and 3, the right side is the downstream side D1 in the conveying direction. The surfaces on which the

grate segments

15 and 16 are mounted are referred to as mounting surfaces, and the angle on the conveying direction D side formed by the horizontal surface and the mounting surfaces with the upstream end portions (11b, 12b, and 13b) of the drying stage, the combustion stage, or the ember stage as the center is referred to as a grate inclination angle (mounting angle). The grate inclination angle is a positive value when the downstream side of the mounting surface in the conveying direction is directed upward with respect to the horizontal plane, and is a negative value when the downstream side of the mounting surface in the conveying direction is directed downward with respect to the horizontal plane.

The mechanical grate 5 includes, in order from the upstream side in the conveying direction of the material T to be incinerated, a drying section 11 for drying the material T to be incinerated, a combustion section 12 for combusting the material T to be incinerated, and an ember section 13 for completely combusting (burning) the unburned components. In the mechanical grate 5, the drying section 11, the combustion section 12, and the burnout section 13 perform drying, combustion, and burnout, respectively, while sequentially conveying the material to be incinerated T.

Each

segment

11, 12, 13 has a plurality of fixed grate segments 15 and a plurality of moving grate segments 16.

The fixed grate segments 15 and the movable grate segments 16 are alternately arranged in the conveying direction D. The moving grate segments 16 reciprocate along the transport direction D of the material to be incinerated T. The reciprocating motion of the moving grate segments 16 is used to convey the objects to be incinerated T on the mechanical grate 5 and stir the objects. That is, the lower portion of the object to be incinerated T is moved to be replaced with the upper portion.

The drying section 11 receives the material T to be incinerated pushed out by the feeder 4 and dropped into the incinerator 3, evaporates moisture of the material T to be incinerated, and thermally decomposes a part thereof. The combustion section 12 ignites the material to be incinerated T dried in the drying section 11 by the primary air supplied from the lower air chamber 6, and burns volatile components and fixed carbon components. The ember zone 13 burns unburned components such as fixed carbon components that have passed through the combustion zone 12 without being sufficiently burned until they are completely ashed.

An ash outlet 17 is arranged at the outlet of the burnout section 13. The ash is discharged from the incinerator 3 through an ash outlet 17.

The drying section 11, the combustion section 12 and the ember section 13 each have a drive mechanism 18 for driving the movable grate segments 16. That is, the drying stage 11, the combustion stage 12, and the ember stage 13 each independently have a drive mechanism 18 for driving the plurality of movable grate segments 16.

The drive mechanism 18 is mounted to a beam 19, and the beam 19 is mounted to the mechanical grate 5. The drive mechanism 18 includes a hydraulic cylinder 20 attached to the beam 19, an arm 21 operated by the hydraulic cylinder 20, and a cross member 22 connected to a front end of the arm 21. The cross beam 22 and the moving grate segments 16 are connected via a bracket 23.

According to the drive mechanism 18 of the present embodiment, the arm 21 is operated by the expansion and contraction of the rod of the hydraulic cylinder 20. The cross member 22 is configured to move along the mounting

surfaces

11a, 12a, 13a of the mechanical grate 5 in accordance with the movement of the arm 21, and the cross member 22 is moved to drive the movable grate segments 16 connected to the cross member 22.

The drive mechanism 18 of the present embodiment uses the hydraulic cylinder 20, but is not limited thereto, and for example, a hydraulic motor, an electric cylinder, an electric linear motor, or the like can be used. The form of the driving mechanism 18 is not limited to the above form, and any form of driving mechanism may be used as long as the movable grate segment 16 can be reciprocated. For example, the beam 22 and the hydraulic cylinder 20 may be directly connected to each other without disposing the arm 21.

In the mechanical grate furnace 1 of the present embodiment, the driving speeds of the movable grate segments 16 in the drying stage 11, the combustion stage 12, and the ember stage 13 can be set to the same speed, or different speeds can be set at least in part of the drying stage 11, the combustion stage 12, and the ember stage 13.

For example, when the material T to be incinerated that requires sufficient combustion in the combustion section 12 is thrown in, the combustion can be sufficiently performed by slowing the speed of driving the moving grate segments 16 of the combustion section 12 to slow the conveyance speed of the material T to be incinerated on the combustion section 12.

As shown in fig. 2 and 3, the fixed grate segment 15 and the movable grate segment 16 are disposed to be inclined upward with respect to the mounting

surfaces

11a, 12a, and 13a of the drying stage 11, the combustion stage 12, and the ember stage 13 on the downstream side in the conveying direction. The

grate segments

15 and 16 are arranged such that the tips of the

grate segments

15 and 16 face the downstream side D1 in the conveying direction. Thereby, the movable grate segment 16 operates to convey the objects to be incinerated T on the fixed grate segment 15 to the conveyance direction downstream side D1.

A part of the moving grate segments 16 of the drying section 11 is a grate segment 16P with a projection (the other are ordinary grate segments described later). As shown in fig. 2, the movable grate segment 16 of the range R1 from the downstream side in the conveying direction to 50% to 80% in the length in the conveying direction of the drying section 11 is a grate segment 16P with protrusions. By using the grate segment 16P with the projections, the stirring force can be improved.

As shown in fig. 3, the protruded grate segment 16P has a plate-shaped grate segment main body 25 and a triangular protrusion 26 provided at the front end of the grate segment main body 25. The projection 26 projects upward from the upper surface of the grate segment main body 25. The shape of the projection 26 is not limited to this, and may be, for example, a trapezoidal shape or a circular shape.

Here, the fixed grate segment 15 of fig. 3 is a grate segment without a protrusion on the upper surface of the tip, and this shape is referred to as a normal grate segment.

In the present embodiment, only the movable grate segment 16 is provided as the grate segment 16P with the projections, but the present invention is not limited thereto, and both the movable grate segment 16 and the fixed grate segment 15 may be provided as the grate segments with the projections.

The range of providing the grate segments 16P with projections is not limited to the above range, and for example, all the grate segments of the drying section 11 may be the grate segments 16P with projections.

Further, depending on the nature and type of the material T to be incinerated, all the grate segments (fixed grate segments and movable grate segments) in the drying section may be made common grate segments.

As in the drying section 11, a part of the moving grate segments 16 of the combustion section 12 is a grate segment 16P with protrusions. Specifically, the movable grate segment 16 of the range R2 from the downstream side in the conveying direction to 50% to 80% in the length in the conveying direction of the combustion section 12 is a grate segment 16P with a projection. The other moving grate segments 16 of the combustion section 12 are conventional grate segments. Similarly to the drying section, depending on the nature and type of the material T to be incinerated, both the movable grate segment 16 and the fixed grate segment 15 may be provided as a protruded grate segment, or all the grate segments (the fixed grate segment and the movable grate segment) may be provided as normal grate segments.

In fig. 2, the movable grate segment 16 and the fixed grate segment 15 are all ordinary grate segments, but the grate segments with projections may be used similarly to the drying segment 11 and the combustion segment 12.

Next, the grate inclination angles (installation angles) of the drying stage 11, the combustion stage 12, and the ember stage 13 will be described.

As shown in fig. 2, the drying section 11 of the mechanical grate 5 of the present embodiment is disposed so as to face downward. That is, the mounting surface 11a of the drying section 11 is inclined to be lower on the downstream side in the conveying direction. Specifically, the angle between the horizontal plane centered on the upstream end 11b of the drying section 11 and the conveyance direction side of the mounting surface 11a, that is, the grate inclination angle θ 1 of the drying section 11 is an angle between-15 ° (minus 15 degrees) and-25 ° (minus 25 degrees).

The combustion zone 12 of the mechanical grate 5 of the present embodiment is disposed facing upward. That is, the mounting surface 12a of the combustion stage 12 is inclined so as to be higher on the downstream side in the conveying direction. Specifically, an angle between a horizontal plane centering on the upstream end 12b of the combustion stage 12 and the conveyance direction side of the mounting surface 12a, that is, a grate inclination angle θ 2 of the combustion stage 12 is an angle between +5 ° (positive 5 degrees) and +15 ° (positive 15 degrees).

The ember zone 13 of the mechanical grate 5 of the present embodiment is disposed so as to face upward. That is, the mounting surface 13a of the ember zone 13 is inclined so as to be higher on the downstream side in the conveyance direction. Specifically, an angle between a horizontal plane centering on the upstream end 13b of the ember zone 13 and the mounting surface 13a in the conveying direction, that is, a grate inclination angle θ 3 of the ember zone 13 is an angle between +5 ° (positive 5 degrees) and +15 ° (positive 15 degrees).

A step (fall wall) 27 is formed between the drying stage 11 and the combustion stage 12. The end 11c on the downstream side in the transport direction of the drying section 11 is formed higher than the end 12b on the upstream side in the transport direction of the combustion section 12 in the vertical direction.

Similarly, a step (falling wall) 28 is formed between the combustion stage 12 and the ember stage 13. The downstream end 12c of the combustion stage 12 in the conveyance direction is formed higher than the upstream end 13b of the ember stage 13 in the conveyance direction in the vertical direction.

The end 12c on the downstream side in the conveyance direction of the burn-out stand 12 and the end 13c on the downstream side in the conveyance direction of the burn-out stand 13 are disposed at substantially the same position in the vertical direction, or the end 13c of the burn-out stand 13 is disposed above the end 12c of the burn-out stand 12. The mechanical grate furnace 1 of the present embodiment is an example in which the end 12c on the downstream side in the conveyance direction of the burner stage 12 and the end 13c on the downstream side in the conveyance direction of the ember stage 13 are provided at the same position in the vertical direction.

Next, the reason why the grate inclination angle of the drying section 11 is set to an angle between-15 ° (minus 15 degrees) and-25 ° (minus 25 degrees) will be described.

The function of the drying section 11 is: the moisture in the material to be incinerated T is dried more efficiently by the radiant heat from the flame located above the material to be incinerated T and the sensible heat from the primary air below the grate segments.

Here, the contribution degree of the radiant heat from the flame to the drying is higher than the sensible heat of the primary air, and the drying of the upper layer portion of the object to be incinerated T is likely to progress.

Therefore, the lower layer portion of the material to be incinerated T is moved upward by the stirring action of the grate segments to be replaced with the upper layer portion, thereby increasing the drying speed.

However, even if the stirring operation is performed, since the combustion is not performed basically in the drying section 11, it is necessary to secure a length for sufficiently performing the moisture evaporation. The longer the length, the larger the size of the apparatus and the more expensive the apparatus, so that it is required to shorten the grate length as much as possible.

When the absolute value of the grate inclination angle is larger than the repose angle of the object to be incinerated T, the grate collapses by its own weight, and the object to be incinerated T layer is not formed, and therefore the mechanical grate 5 cannot be configured. On the other hand, when the absolute value of the grate inclination angle is smaller than the repose angle of the object T to be incinerated, the mechanical grate can be configured, but the movement due to the gravity of the object T to be incinerated (the movement due to its own weight) is reduced. When the mounting surface is inclined upward, that is, inclined such that the grate inclination angle is a positive value (positive value), gravity acts in a direction of pushing back the object to be incinerated T from the conveying direction.

When the transport amount of the objects to be incinerated T by the mechanical grate 5 is less than the amount of the objects to be incinerated T to be charged, the transport limit is set, and the objects cannot be treated.

The optimum grate inclination angle differs depending on the amount of the material T to be incinerated charged and the moisture content of the material T to be incinerated. Here, a case where the load of the input object to be incinerated is large will be described as a case where the amount of the input object to be incinerated T is large and the water content is high (the water content is large). Conversely, a case where the amount of the material to be incinerated T to be charged is small and the water content is low is a case where the load of charging the material to be incinerated is small.

Fig. 4 shows an example as follows: the relationship between the inclination angle of the grate in the drying section 11 and the required grate length in the drying section 11 is plotted in the order from the case (1) where the load of the object to be incinerated is the maximum to the case (4) where the load of the object to be incinerated is the minimum, with the inclination angle of the grate in the drying section 11 on the horizontal axis as the inclination angle of the grate in the drying section 11 and the required grate length in the drying section 11 on the vertical axis as the required grate length in the drying section 11.

Here, the necessary grate length means a distance for drying 95% of the moisture of the charged material to be incinerated T. The "repose angle" on the horizontal axis represents the repose angle of the material to be incinerated T.

As shown in the graph of FIG. 4, the grate inclination angle of-30 is the limit for forming T layers of the material to be incinerated. The necessary grate length is reduced by making the grate inclination angle gradually smaller with respect to the grate inclination angle at the limit of the layer, but becomes gradually longer when the grate inclination angle is changed to a positive value. This is because when the grate inclination angle is positive, the mounting surface faces upward, and the transport speed is reduced, resulting in a thick layer of the object to be incinerated T and making it difficult to dry the object to be incinerated T in the lower layer.

As can be seen from the four cases from the case (1) where the load of the objects to be incinerated T to be charged is maximum to the case (4) where the load of the objects to be incinerated T to be charged is minimum, the objects to be incinerated T can be appropriately treated regardless of the shape and amount thereof, and the angle between-15 ° (minus 15 degrees) and-25 ° (minus 25 degrees) of the grate inclination angle of the drying section 11, which is the optimum one where the grate length is shortest, can be set to an appropriate range. And, the optimum value is-20 ° (minus 20 degrees).

Next, the reason why the grate inclination angle of the combustion section 12 is preferably set to an angle between +5 ° (positive 5 degrees) and +15 ° (positive 15 degrees) when the grate inclination angle of the drying section 11 is set to an appropriate range as described above will be described.

The function of the combustion section 12 is: the temperature of the material to be incinerated T layer is maintained by the radiant heat from the flame and the self-ignition heat, and combustion of the remaining fixed carbon is promoted by the generation of combustible gas due to the thermal decomposition of the volatile component.

Here, since the time required for the combustion of the fixed carbon is longer than the time required for the volatilization of the volatile combustible gas, the necessary grate length of the combustion section 12 is determined by the time required for the combustion of the fixed carbon.

In fig. 5, when the grate inclination angle of the drying section 11 is set to the appropriate range as described above, the horizontal axis is the grate inclination angle of the combustion section, and the vertical axis is the necessary grate length of the combustion section, and the relationship between the grate inclination angle of the combustion section and the necessary grate length of the combustion section is plotted from the case (1) where the load for charging the object to be incinerated is the maximum to the case (4) where the load for charging the object to be incinerated is the minimum. Herein, the necessary grate length of the combustion section is the distance over which 95% of the combustible components are volatilized or combusted.

As shown in FIG. 5, the inclination angle of the grate is-30 deg. which is the limit for forming T layer of the object to be incinerated. The angle of inclination of the grate relative to the limit of the layer is made to slow, and the necessary grate length is reduced accordingly. In consideration of the transportation limit, the appropriate range of the grate inclination angle can be set to a range surrounded by a chain line shown in fig. 5.

In the drying section 11, even when the load of loading the object to be incinerated is large, the grate inclination angle of the drying section 11 is within an appropriate range, so that the drying section 11 can promote the reduction of the moisture content and the volume of the garbage. Therefore, for example, even if the load in the drying section 11 is the load corresponding to (1), the load changes to the loads corresponding to (3) and (4) in the combustion section 12, and therefore, a larger grate inclination angle can be adopted in the combustion section 12. That is, since the combustion section can be directed upward, the residence time required for the combustion of the fixed carbon can be ensured, and the grate length can be shortened.

In fig. 6, the relationship between the grate inclination angle of the combustion section 12 and the grate lengths required for both the drying section 11 and the combustion section 12 is plotted, with the horizontal axis being the grate inclination angle of the combustion section 12 and the vertical axis being the grate lengths required for both the drying section 11 and the combustion section 12, from the case (1) where the load of the thrown object T is the maximum to the case (4) where the load of the thrown object T is the minimum. Here, the grate inclination angle of the drying section 11 is-20 ° (minus 20 degrees) as an optimum value.

As shown in fig. 6, it can be seen that: a suitable range for the grate inclination angle of the combustion section 12 is an angle between +8 ° (plus 8 degrees) and +12 ° (plus 12 degrees) in view of the transport limits. In addition, in the case where the grate inclination angle of the drying section 11 is-20 ° (minus 20 degrees) as an optimum value, the grate inclination angle of the combustion section 12 is +10 ° (+10 degrees) as an optimum value.

Since the necessary grate lengths of the drying section 11 and the combustion section 12 can be set to a shorter grate length as much as possible by setting the inclination angles of the respective grates to appropriate ranges, particularly to optimum values, a mechanical grate furnace that is small in size and can be reduced in cost can be provided even if the ember section 13 is included.

According to the above embodiment, the drying section 11 is inclined downward, whereby the material to be incinerated T of any kind of property can be conveyed to the combustion section 12 without being retained, and the combustion section 12 and the ember section 13 are inclined upward, whereby the material to be incinerated T is sufficiently combusted and conveyed without easily sliding or rolling down the material to be incinerated to the downstream of the combustion section 12.

That is, in the case of the material which is easily slipped or the material to be incinerated T which is easily rolled, since the material is early conveyed to the combustion section 12 by rolling in the drying section 11, there is a possibility that the material cannot be sufficiently dried in the drying section 11. However, since the combustion section 12 and the ember section 13 are inclined upward, the burned material T after the rolling in the drying section 11 does not further roll in the combustion section 12 and the ember section 13, and is inevitably sufficiently dried and burned in the combustion section 12. Since the material to be incinerated T having a high water content is dried without being retained in the drying section 11 and is then transported to the combustion section 12, the material to be incinerated T is inevitably sufficiently incinerated in the combustion section 12 as well.

This enables the continuous feeding of the material to be incinerated T regardless of the properties of the material to be incinerated T, and the complete burning of the material to be incinerated T.

The end 13c on the downstream side in the conveyance direction of the ember zone 13 is disposed at substantially the same position as the end 12c on the downstream side in the conveyance direction of the burner zone 12 in the vertical direction, or at a position above the end 12c of the burner zone 12. Thus, even when the burned material T falls down in the drying section 11, the burned material T can be prevented from being discharged from the ember section 13 in a state where the burned material T is not sufficiently burned.

[ second embodiment ]

Hereinafter, a mechanical grate furnace according to a second embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that, in the present embodiment, differences from the first embodiment will be mainly described, and descriptions of the same portions will be omitted.

As shown in fig. 7, there is no stage (falling wall) between the combustion zone 12 and the ember zone 13 of the mechanical grate 5 of the present embodiment. That is, the burner stage 12 of the present embodiment is continuously connected to the ember stage 13. In other words, the end 12c on the downstream side in the conveyance direction of the burn-up stage 12 and the end 13b on the upstream side in the conveyance direction of the burn-up stage 13 are formed to have the same height.

According to the above embodiment, even if the object T to be incinerated after rolling in the drying section 11 has a strong momentum and passes through the burning section 12 with the momentum, the object T is stopped at least in the ember section 13 and is not discharged from the ember section 13. Further, by continuously connecting the ember stage 13 and the combustion stage 12 without stages, even if the insufficiently burned material to be incinerated T enters the ember stage 13 by rolling or the like, the insufficiently burned material to be incinerated T can be returned to the combustion stage 12 by its own weight and burned. That is, the discharge of the material to be incinerated T that is not completely combusted can be reduced as much as possible.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments, and design changes and the like without departing from the scope of the present invention are also included.

In the above embodiment, the front ends of the

grate segments

15 and 16 are arranged to face the downstream side D1 in the conveying direction, but the present invention is not limited to this, and for example, the front ends of the

grate segments

15 and 16 in the drying section 11 may be arranged to face the upstream side in the conveying direction.

Description of reference numerals:

1 mechanical grate furnace

2 hopper

3 incinerator

4 feeder

5 mechanical fire grate

6 air chamber

7 feeder platform

8 feeder driving device

9 combustion chamber

10 blower

11 drying section

11a mounting surface of drying section

12 combustion section

12a combustion section mounting face

13 burn-out section

13a mounting surface of the ember section

15 fixed fire grate segment

16 moving fire grate segment

16P fire grate sheet with projections

17 ash outlet

18 driving mechanism

19 Beam

20 hydraulic cylinder

21 arm

22 Cross member

23 support

25 fire grate segment main body

26 projection

27. Stage 28 (drop wall)

D conveying direction

Downstream side in the conveying direction of D1

T-shape incinerated substance

Theta 1, theta 2 and theta 3 fire grate inclination angles.

Claims

1. A mechanical grate furnace for burning an object to be burned, which supplies the object to be burned from a feeder, and performs drying, burning and burning while sequentially conveying the object to be burned in a drying section, a burning section and a burning section which are provided with a plurality of fixed grate segments and a plurality of movable grate segments,

the mechanical grate furnace for burning the substances to be incinerated is characterized in that,

the drying section is disposed obliquely so that a downstream side in the conveying direction faces downward,

the combustion section is connected to the drying section and is disposed so as to be inclined such that a downstream side in the conveying direction faces upward,

the ember zone is connected to the combustion zone and is disposed so as to be inclined such that the downstream side in the conveyance direction faces upward, and an end portion on the downstream side in the conveyance direction of the ember zone is disposed at the same position as the end portion on the downstream side in the conveyance direction of the combustion zone or above the end portion of the combustion zone in the vertical direction.

2. The mechanical stoker furnace for burning an object to be incinerated according to claim 1,

the fixed grate segment and the movable grate segment are disposed in an inclined manner such that the downstream side in the conveying direction faces upward with respect to the mounting surfaces of the drying section, the combustion section, and the ember section.

3. The mechanical stoker furnace for burning an object to be incinerated according to claim 2,

the drying section, the combustion section, and the ember section each independently have a drive mechanism for driving the plurality of movable grate segments provided in the drying section, the combustion section, and the ember section,

setting the speeds of the driving in the drying section, the combustion section, and the ember section to be the same speed as each other, or to be different speeds in at least a part of the drying section, the combustion section, and the ember section.

4. The mechanical stoker furnace for burning an object to be incinerated according to claim 3,

the combustion section is continuously connected to the ember section without a stage.

5. The mechanical stoker furnace for burning an object to be incinerated according to claim 3 or 4,

at least a part of the plurality of movable grate segments of the drying section is a grate segment provided with a protrusion at the front end.

6. The mechanical stoker furnace for burning an object to be incinerated according to claim 5,

at least a part of the plurality of movable grate segments of the combustion section is a grate segment provided with a protrusion at the front end.

7. The mechanical stoker furnace for burning an object to be incinerated according to claim 6,

the grate inclination angle of the drying section is configured to be an angle between-15 degrees and-25 degrees, and the grate inclination angle of the combustion section is configured to be an angle between +8 degrees and +12 degrees.

8. The mechanical stoker furnace for burning an object to be incinerated according to claim 6,

the grate inclination angle of the drying section is configured to be an angle between-15 degrees and-25 degrees, and the grate inclination angle of the ember section is the same as the grate inclination angle of the combustion section.

9. The mechanical stoker furnace for burning an object to be incinerated according to claim 7 or 8,

the inclination angle of the grate of the drying section is-20 degrees, and the inclination angle of the grate of the combustion section is +10 degrees.