JP2022089410A - Fire grade combustion system and fire grade combustion method - Google Patents

Abstract

To improve a fire grade combustion system and a fire grade combustion method to perform combustion of wastes properly in a harsh furnace environment.SOLUTION: A fire grade combustion system 100 includes: a supply hopper 1; a supply fire grade 2; a fire grade device 3; a furnace 4; a secondary air injection device 5; an auxiliary combustion device 6; a primary air suction and ash slag collection device 7; a steel support structure 8; and a control device 20. Solid wastes to be supplied to the furnace 4 are stored in the supply hopper 1. The supply fire grade 2 is provided below the supply hopper 1. The fire grade combustion system 100 is provided with a drive device which reciprocates the supply fire grade 2 forward and rearward. The fire grade device 3 includes fire grades 30, 31. The fire grade device 3 receives the solid wastes from the supply fire grade 2. The furnace 4 houses the fire grade device 3.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a grate combustion system and a grate combustion method.

Japanese Unexamined Patent Publication No. 2017-078534 describes a waste incinerator system including a refractory-coated grate.

Japanese Unexamined Patent Publication No. 2017-078534

As people's living standards improve and the development of civilization accelerates, waste classification becomes more detailed and the calorific value of combustible waste continues to increase. Due to changes in combustible waste, the environment inside the incinerator is also likely to be harsher. Improvements in the grate combustion system and grate combustion method are required so that waste can be properly incinerated even in a harsh incinerator environment.

One aspect of the grate combustion system comprises a furnace and a grate device provided in the furnace. The present disclosure provides several improvements to the grate combustion system, including, for example, the improved structures listed below. Each improved structure may be used independently of each other and separately, or may be used in combination with each other.

As one of the improved structures in the above aspect of the grate combustion system, the grate device comprises a plurality of grate stacked in a stepped manner so as to form a multi-stage grate group, and the plurality of fires. The grid may include a row-integrated grate having a grate plate integrally continuous in the row direction. According to such a row-integrated structure, since the grate has an integrally continuous structure having no gap in the middle of the row direction, there is an advantage that ash, dust residue, or water can be suppressed from leaking below the grate. There is.

As another one of the improved structures in the above aspect of the grate combustion system, the plurality of grate are stacked in a stepped manner so as to form a multi-stage grate group each including a plurality of grate. May be good. In the above aspect, the plurality of air chambers provided below each of the plurality of stages of the grate group are communicated with each of the plurality of air chambers, and the amount of air blown to each of the plurality of air chambers is different from each other. Further may be provided with a blower device constructed so that the amount of blown air can be adjusted. As a result, the amount of air blown to each air chamber can be adjusted, which has the advantage that the combustion temperature can be adjusted with a high degree of freedom.

As yet another one of the improved structures in the above aspect of the grate combustion system, the plurality of grate includes a plurality of sliding grate that are overlapped with the row-integrated grate and each of which is reciprocally displaced. The grid device includes a front end portion and a rear end portion, a plurality of hydraulic cylinders for driving the plurality of sliding grate reciprocating back and forth, and a hydraulic pressure tank connected to the plurality of hydraulic cylinders. The pressure tank may be constructed so as to be arranged only on the side of the front end portion of the grate device. As a result, the hydraulic tank can be uniformly arranged on the side closer to normal temperature, which has an advantage that the risk of liquid leakage can be suppressed.

As yet another of the improved structure in the above aspect of the grate combustion system, the grate device is at least a water-cooled fixed grate and a sliding type that is superposed on the fixed grate and reciprocates back and forth. It may be equipped with a pure air-cooled sliding grate, which is constructed in the air and is cooled only by air among air and cooling water. By letting the water-cooled grate play the role of a fixed grate, it is not necessary to slide the water-cooled grate, so there is an advantage that the risk of cooling water leakage can be suppressed.

One aspect of the grate combustion method comprises a combustion step and a cooling step. The present disclosure provides several improvements to the grate burning method, including, for example, the improved methods listed below.

As one of the improved methods in the above aspect of the grate combustion method, the combustion step has a plurality of row-integrated fixed grate having a grate plate having a continuous shape in the row direction in the furnace. The solid waste on the row-integrated fixed grate is generated by reciprocating the sliding grate arranged at each of the upper and lower intervals in a state of being stacked in a stepped manner with a vertical interval between them. It may be a step of burning while stirring. Further, in the cooling step, when the solid waste is burned in the combustion step, the row-integrated fixed grate and the back surface of the row-integrated fixed grate and the sliding grate are cooled while cooling the row-integrated fixed grate in a water-cooled manner. It may be a step of cooling the row-integrated fixed grate and the sliding grate by air-cooling by sending air from the side.

A grate combustion system and grate combustion method that can operate properly even in a harsh in-fire environment are provided.

It is a system block diagram of the grate combustion system of embodiment. It is a schematic block block diagram for demonstrating the grate combustion system of embodiment. It is sectional drawing which shows the structure of the grate device of embodiment. It is a schematic front view which looked at the grate device of embodiment from the front side. It is an enlarged cross-sectional view of the grate peripheral part of the grate apparatus of embodiment. It is a perspective view which showed the periphery of the grate of the grate apparatus of embodiment. It is a system block diagram of the grate combustion system of the modification of embodiment.

In embodiments, some figures illustrate XYZ orthogonal axes. This XYZ direction is defined for convenience to illustrate embodiments. The X direction represents the length direction of the grate combustion system 100. The X direction is the direction in which the grate device 3 sends out solid waste in the grate combustion system 100. The Y direction represents the width direction of the grate combustion system 100, and also corresponds to the width direction of the grate device 3 and the furnace 4. For convenience, the Z direction represents the height direction of the grate combustion system 100. As illustrated in some figures, in embodiments, for convenience, the positive orientation on the X-axis is the rear side of the grate combustion system 100. In the embodiment, for convenience, the negative direction on the X-axis is the front side of the grate combustion system 100.

FIG. 1 is a system configuration diagram of the grate combustion system 100 of the embodiment. As shown in FIG. 1, the grate combustion system 100 includes a supply hopper 1, a supply grate 2, a grate device 3, a furnace 4, a secondary air injection device 5, an auxiliary combustion device 6, and a primary. It includes an air intake / ash slag collecting device 7, a steel support structure 8, and a control device 20.

The supply hopper 1 stores solid waste to be supplied to the furnace 4. The supply grate 2 is provided below the supply hopper 1. A drive device (not shown) for reciprocating the supply grate 2 back and forth is provided. The grate device 3 includes a plurality of grate 30, 31. The grate device 3 receives solid waste from the supply grate 2. The furnace 4 houses the grate device 3. The secondary air injection device 5 includes a plurality of secondary air nozzles provided in the throat above the furnace 4.

The auxiliary combustion device 6 is provided at the tail end portion 4c at the rear end of the furnace 4. The primary air intake and ash slag collecting device 7 is provided below the grate device 3. The steel support structure 8 supports the supply grate 2. The control device 20 controls the operation of each component included in the grate combustion system 100.

More specifically, in the embodiment, as an example, each configuration of the grate combustion system 100 is constructed as follows. The supply hopper 1 is a funnel made of wear-resistant steel and carbon steel. The underside of the funnel is constructed in a flared shape to prevent cross-linking and blockage of the material.

As will be shown later in FIGS. 3 to 5, the grate 30 and 31 of the embodiment include, for example, an air / water mixed cooling type fixed grate 30 and a pure air-cooled sliding grate 31. The sliding grate 31 that pushes the material is, for example, a long stroke roller type material driving device.

A primary air intake and ash slag collecting device 7 is provided below the grate device 3. The primary air intake / ash slag collecting device 7 includes a "primary air intake device" and a "ash and slag collecting device (hopper)". The ash slag collection hopper in the primary air chamber is provided with a daily maintenance support platform. The ash slag collection hopper is equipped with a grill device. The grill device is a device for blocking coarse dust.

Although not specified in the figure, the grate combustion system 100 of the embodiment is also provided with a slag discharge hopper. The slag discharge hopper is equipped with a water cooling device. The water cooling device is a device for preventing the unburned material from entering the slag discharging device and becoming locally hot. The slag discharge hopper is provided with a water-sealed slag discharge device. The water-sealed slag discharge device is a device for extinguishing a fire or preventing air leakage in the furnace 4.

The secondary air nozzles of the secondary air injection device 5 are installed on the front wall 4a and the rear wall 4b in the throat of the furnace 4, respectively. The secondary air injection device 5 includes a plurality of secondary air nozzles for supplying secondary air. The secondary air nozzle is constructed to separately inject secondary air through several branch pipes.

The auxiliary combustion device 6 may be equipped with an oil burner or a gas burner, if necessary.

FIG. 2 is a schematic block configuration diagram for explaining the grate combustion system 100 of the embodiment. The grate combustion system 100 of the embodiment is a double cooling system by mixing air and water. Solid waste is supplied to the grate device 3 in the furnace 4 via the supply hopper 1 and the supply grate 2. Primary air 71 is supplied to the grate device 3. At the same time, "leaked ash and slag 72" and "slag 73 after combustion" are discharged from the grate device 3.

The primary air intake / ash slag collecting device 7 includes a primary air chamber for sending the primary air 71. The primary air chamber is also provided with a hopper function for collecting ash and slag. At the same time as the solid waste is burned, the primary air 71, which is the main combustion air, is uniformly sent to the grate device 3 through the primary air chamber. The primary air 71 and the combustion material are well mixed with each other. According to the embodiments, the primary and secondary air supply and the special design in the furnace 4 provide complete and effective combustion of solid waste. It can also reduce, stabilize, and detoxify solid waste and provide thermal energy to the outside world.

3 to 6 are diagrams for explaining the detailed structure of the grate device 3 of the embodiment. FIG. 3 is a cross-sectional view showing the configuration of the grate device 3 of the embodiment.

As shown in FIG. 3, the grate device 3 includes a fixed grate 30, a sliding grate 31, and a drive device 40. In the embodiment, the fixed grate 30 is an air / water mixed double cooling type grate, and the sliding grate 31 is a pure air-cooled grate.

By mixing the water-cooled type and the air-cooled type while using them properly, there is an advantage of suppressing water leakage. That is, it is assumed that a water-cooled grate is used as a sliding grate. In this case, in order to realize the sliding of the water-cooled grate, various drive structures and connecting parts for guiding the cooling water are provided in each part of the water-cooled grate. The parts provided with the connecting parts are, for example, between the launch port of the cooling water supply pipeline and the launch port of the cooling water channel provided in the sliding grate. Since the sliding grate is repeatedly displaced back and forth back and forth, there is a drawback that the cooling water is likely to leak due to the burden on the connecting portion between the sliding grate and the connecting parts over time. In this respect, in the embodiment, the fixed grate 30 which is an air / water mixed double cooling type is fixed at a fixed position, while the sliding grate 31 which is a pure air cooling type does not include a water cooling mechanism. Therefore, it is possible to reduce the concern about water leakage caused by the reciprocating sliding of the water-cooled grate.

FIG. 4 is a schematic front view of the grate device 3 as viewed from the front side thereof. As can be seen from FIGS. 3 and 4, the drive device 40 is provided only on the front end portion 3f of the grate device 3.

As shown in FIGS. 3 and 4, the drive device 40 is centrally installed only in the front end portion 3f of the grate device 3, which has the following advantages. The hydraulic drive device 40 includes a hydraulic tank (more specifically, a hydraulic tank in the embodiment). Installing the hydraulic tank in a normal temperature area has the advantage of not being affected by high temperatures and the risk of water leakage. By unifying the installation location, there is also the advantage that it is easy to inspect and repair the hydraulic tank.

It is assumed that the hydraulic drive device 40 is installed on the side surface portion or the lower surface portion of the grate device 3. Then, the hydraulic tank of the drive device 40 is installed near the high temperature combustion area. The high temperature may cause water leakage or component failure. Further, it is assumed that the drive devices 40 are distributed and arranged at a plurality of locations of the grate device 3. Then, since the installation location is not unified, there is a drawback that inspection and repair become difficult. In this regard, according to the embodiment, these problems can be suppressed by centrally installing the drive device 40 only in the front end portion 3f of the grate device 3.

The drive device 40 reciprocates a plurality of hydraulic cylinders 41 in the front-rear direction. The drive device 40 reciprocates the sliding grate 31 in the front-rear direction of the grate device 3. This reciprocating motion completely rotates the waste and evenly stirs and mixes it. Heads are provided on the grate 30 and 31 of each level. This head allows the solid waste to be burned uniformly and gradually from the front end 3f of the grate device 3 to the slag collection hopper at the rear end 3r.

The hydraulic cylinder 41 is made of a high temperature and corrosion resistant material. The drive device 40 is, as an example, a hydraulic drive type. However, the present invention is not limited to this, and as a modification, the drive device 40 may be, for example, an electric drive type, and the hydraulic cylinder 41 may be an electric cylinder.

The primary air intake / ash slag collecting device 7 sends the primary air 71 from below the grate device 3. In FIG. 3, the primary air 71 is schematically illustrated by an arrow. The primary air 71 is supplied from below the grate device 3, that is, from the back surface side of the grate 30 and 31.

FIG. 5 is an enlarged cross-sectional view of a portion around the grate of the grate device 3 of the embodiment. FIG. 5 is an enlarged view of the portion shown by the broken line frame P in FIG. FIG. 6 is a perspective view showing the periphery of the grate of the grate device 3 of the embodiment. As shown in FIGS. 5 and 6, the fixed grate 30 and the sliding grate 31 are alternately arranged at intervals.

As shown in FIG. 6, the fixed grate 30 of the embodiment includes, as an example, a grate plate 30a having an integrated design. Due to the integrated design, the grate plate 30a is constructed as a continuous member in a row (sheets). The grate plate 30a has a length dimension L and a width dimension W. The grate plate 30a includes a "continuous single plate structure without breaks, breaks, or gaps in the middle of the row direction (that is, a" row-integrated structure ")". The "row direction" is the depth direction of the paper surface in FIG. 6, and is the direction along the length dimension L of the grate plate 30a. In the embodiment, the grate plate 30a is cooled by the air / water mixed double cooling method. That is, the grate plate 30a is provided with a cooling water channel extending in the plane direction thereof.

The grate plate 30a of the integrated design has no breaks (in other words, breaks or gaps) in the row direction. Therefore, there is an advantage that ash, dust residue, water, or the like can be prevented from leaking to the back side of the grate plate 30a.

The air / water mixed double cooling type fixed grate 30 is required to have strict requirements for welding quality. Therefore, after the fixed grate 30 is constructed by welding, the hydraulic test and the heat treatment may be performed as a whole. The water pressure test and the heat treatment may be carried out by a professional welding worker and the manufacturer.

The sliding grate 31 of the embodiment includes, as an example, a "plurality of parallel structure". The multiple-sheet parallel structure is a structure in which several grate pieces (or grate lumps) are arranged in a row in the direction penetrating the paper surface of FIG. Therefore, the sliding grate 31 of the embodiment has a break (in other words, a break or a minute gap) in the middle of the row direction. Further, as already described, the sliding grate 31 is a pure air-cooled type. The pure air-cooled type is a method in which water cooling is not applied and only air cooling is used. Therefore, the grate plate of the sliding grate 31 is not provided with a cooling water channel.

As shown in FIG. 5, in the embodiment, one grate group is formed by one fixed grate 30 and a plurality of sliding grate 31 having a parallel structure. Under normal combustion conditions, about 4/5 of the pure air-cooled sliding grate 31 is completely shrunk under the air / water mixed double cooling fixed grate 30. As a result, both of the two types of grate 30, 31 are protected.

The inclination angle θ1 in FIG. 5 is an angle formed by the fixed grate 30 and the sliding grate 31 with respect to the horizontal plane. As an example, the tilt angle θ1 may be set to 18 to 29 degrees. In FIG. 5, the angle formed by the cutting edges of the grate 30 and 31 of each stage with respect to the horizontal direction is defined as the cutting edge angle θ2. The cutting edge angle θ2 may be 0 to 5 degrees. In FIG. 5, the height of the fixed grate 30 is defined as the height h1. The height h1 may be 100 mm to 150 mm as an example. In FIG. 5, the height dimension of the sliding grate 31 is defined as the height h2. The height 2 may be, for example, 120 mm to 200 mm, or h1 <h2.

FIG. 5 shows a hydraulic cylinder 41a and a hydraulic cylinder 41b. The hydraulic cylinder 41a of the first group is connected to the sliding grate 31a in the first row and the sliding grate 31c in the third row, and drives them back and forth. The hydraulic cylinder 41b of the second group is connected to the sliding grate 31b in the second row and the sliding grate 31d in the fourth row, and drives them back and forth.

The cooling water flows in from the front end (lower part) of the fixed grate 30, flows while exchanging heat inside the fixed grate 30, and is discharged as hot water from the rear end (lower part) of the fixed grate 30. When placed in harsh combustion conditions, cooling water evaporates inside the fixed grate 30 to generate air resistance. Therefore, an air vent valve may be installed at a relatively high portion of the drainage pipe, for example. This is to prevent the cooling effect from being affected.

The operation of the grate combustion system 100 of the embodiment may be carried out as in the following steps S1 to S5 as an example. Some or all of the operations of each step may be performed integrally in the control device 20.

(Step S1) Before the furnace 4 is started and ignited, the supply hopper 1 is filled with solid waste until it is full.

(Step S2) The auxiliary combustion device 6 is ignited, the furnace 4 is heated, and the temperature of the furnace 4 is raised to 650 degrees or higher.

(Step S3) The door of the supply hopper 1 is opened. Solid waste freely falls toward the supply grid 2 due to gravity. The solid waste is carried to the supply grid 2 via the supply hopper 1.

(Step S4) When the supply grid 2 is activated, the supply grid 2 pushes the solid waste into the grate device 3. The solid waste supplied to the grate device 3 burns on the fixed grate 30. Along with the combustion, the reciprocating displacement of the sliding grate 31 pushes the solid waste from the front end 3f side of the grate device 3 to the rear end 3r side. The reciprocating displacement of the sliding grate 31 completely pushes the solid waste, so that the solid waste is agitated and sufficiently burned. At the same time, the damper baffle of the primary air intake and ash slag collector 7 is opened, whereby the combustion air and the material are completely mixed in the furnace 4. The reaction occurs under high temperature action in the furnace 4. The air for combustion is sent into the furnace 4 via the primary air intake and ash slag collecting device 7 provided below the grate 30 and 31. The secondary air is sent into the furnace 4 through the upper throat of the furnace 4.

(Step S5) During the incineration of the solid waste in step S4 above, the grate 30 and 31 are cooled by water cooling and air cooling. Cooling by water cooling is performed only by the fixed grate 30. Water cooling is realized by supplying cooling water to the cooling water channel provided in the fixed grate 30. Cooling by air cooling is performed on both the grate 30 and 31. Air cooling can be carried out by supplying air to the grate 30 and 31, but air cooling may be realized by supplying air to the back surface side of the grate 30 and 31, for example.

(Step S6) The slag 73 after combustion (see FIG. 2) is discharged to the outside via the ash and slag collecting mechanism provided in the primary air intake and ash slag collecting device 7.

According to the grate combustion system 100 and the grate combustion method (steps S1 to S6) of the embodiment described above, the fixed grate 30 that is constantly exposed to high temperature in the furnace is an air / water mixed double cooling system. Column-integrated structure Constructed as a fixed grate. As a result, it is possible to withstand a harsh in-furnace environment with a high cooling effect while simultaneously achieving suppression of leakage of ash and the like and suppression of cooling water leakage risk. On the other hand, it is also possible to sufficiently burn the solid waste by combining the reciprocating displacement of the sliding grate 31. According to the embodiment, by accurately adjusting the supply of solid waste and the air supply, it is possible to treat and incinerate solid waste having a calorific value range of 1000 kcal / kg to 7000 kcal / kg, for example. And a practical grate combustion system and grate combustion method are provided.

In the above embodiment, the design value of each configuration may be variously determined, or each configuration may be variously modified.

The grate device 3 may be composed of several "grate groups". Each grate group shall include several grate modules. "Grate module" refers to a group of grate of each step stacked in a staircase pattern. For example, one grate module may be constructed of a laminate of one fixed grate 30 and one sliding grate 31. For example, as shown in FIG. 5, one "grate group" may be constructed by a four-stage grate module. In the example shown in FIG. 5, four fixed grate 30s and four sliding grate 31s are stacked in a staircase pattern, and different grate appear alternately one by one. The number of stages of the grate module included in the grate group is not limited to four, and one grate group may be constructed with any number of stages such as two stages, three stages, five stages, or six stages.

In the embodiment, as shown in FIG. 5, in one "grate group", the air / water mixed double cooling type fixed grate 30 is installed relatively on the upper side, and is a pure air cooling type. The sliding grate 31 of the above is installed relatively lower. The fixed grate 30 is an air / water mixed double cooling type. On the other hand, the sliding grate 31 is a pure air-cooled type. The grate 30, 31 may be arranged in two stages. The material rolling guide wall between the first stage and the second stage will be described. The material rolling guide wall is a term that refers to a high amount of waste disposal. Specifically, for example, in the example of FIG. 5, the height hg of the material rolling guide wall is "the height h2 for the sliding grate 31a, the height h1 of the grate 30, and the height of the sliding grate 31b. Total with h2 ". The height hg of the material rolling guide wall may be 400 mm to 800 mm as an example.

In the embodiment, the drive device 40 for driving the sliding grate 31 is collectively installed at the front end portion 3f of the grate device 3, that is, centrally. However, as a modification, the drive device 40 may be distributed and installed at a plurality of locations of the grate device 3.

As shown in FIG. 5, the sliding grate 31 has a movable distance (stroke distance) Ds. The movable distance (stroke distance) Ds may be 200 mm to 450 mm as an example.

A heat insulating path, an air-cooled furnace, and a water-cooled furnace may be provided on the side wall of the furnace 4 depending on the calorific value range of the solid waste to be treated. For example, an adiabatic furnace may be provided according to the calorific value range of 1000 kcal / kg to 1800 kcal / kg. For example, an air-cooled furnace may be provided according to the calorific value range of 1801 kcal / kg to 2500 kcal / kg. For example, a water cooling furnace may be provided according to the calorific value range of 2501 kcal / kg to 7000 kcal / kg.

For example, in embodiments, individual devices may be optionally replaced with existing known or well-known techniques. For example, the supply hopper 1 described above, the ash slag collection hopper, the slag discharge hopper, the burner of the auxiliary combustion device 6, the hydraulic cylinder 41, and the secondary air nozzle of the secondary air injection device 5 are existing. It may be constructed by a known technique or a known technique.

FIG. 7 is a system configuration diagram of a grate combustion system 101 of a modified example of the embodiment. The grate combustion system 101 of the modified example further includes an air pipeline 17, a plurality of blowers (fans) 18, a circulating flue gas flow path 19, a circulating flue gas injection port 19a, and a double nozzle 19q. There is. The control device 20 controls the operation (on / off control and air volume) of each of the plurality of blowers (fans) 18. The control device 20 also controls the operation of the circulating flue gas injection port 19a and the double nozzle 19q. The control contents of the circulating flue gas injection port 19a and the double nozzle 19q include at least on / off control, and may include injection amount control when these are flow rate adjustable mechanisms.

In FIG. 7, among a plurality of grate 30s and 31s included in the grate device 3, a group of grates located closest to the front end portion 3f side is shown as a first-stage grate group 3a. Further, in FIG. 7, the symbols 7a to 7e are attached to a plurality of air chambers (primary air chambers) provided in the primary air intake / ash slag collecting device 7. The wind chamber 7a is provided below the first stage grate group 3a. The air chambers 7b to 7e are provided below each of the grate groups in the second and subsequent stages.

In the grate combustion system 101 of the modified example, the air pipeline 17 is branched into a plurality of branch pipelines on the way. A blower 18 is provided in each of the branch pipelines. The discharge ports of the plurality of blowers 18 are individually connected to each of the plurality of air chambers (primary air chambers) 7a to 7e provided below the grate device 3. The plurality of blowers 18 are constructed so that the wind power adjustment control can be performed separately for each of the blowers 18. The control may be carried out by the control device 20. By adjusting the amount of air blown to each primary air chamber, the combustion temperature can be adjusted more accurately, and the generation of contaminants (mainly NOx) can be suppressed. In addition, the combustion air ratio becomes more accurate, and there is an advantage that the combustion efficiency becomes high.

The grate combustion system 101 of the modified example is provided with a circulating flue gas flow path 19 and a circulating flue gas injection port 19a. One end of the circulating flue gas flow path 19 is connected to the furnace 4. The other end of the circulating flue gas flow path 19 is connected to a predetermined branch line 17a among a plurality of branch lines of the air line 17. The predetermined branch pipeline 17a communicates with the wind chamber 7a, which is a primary air chamber provided below the first stage grate group 3a. Inside the air chamber 7a, a double nozzle 19q is provided at the tip of the predetermined branch pipe line 17a. The double nozzle 19q can supply the air chamber 7a with a mixed gas in which the primary air 71 (see FIG. 2) from the air conduit 17 and the circulating flue gas from the circulating flue gas flow path 19 are mixed. can.

The circulating flue gas injection port 19a is provided above the grate 30 and 31 of the first stage grate group 3a. As shown in FIG. 7, the circulating flue gas injection port 19a may be provided above the first stage grate group 3a, but the present invention is not limited to this, and the circulating flue gas injection port is not limited to this. 19a may be provided.

In the modified example, the circulating flue gas is supplied in place of or together with air, particularly in the first stage grate group 3a in the grate device 3. The burned gas taken out from the inside of the furnace 4 is circulated to the air chamber 7a as a circulating flue gas through the circulating flue gas flow path 19 and the double nozzle 19q, or through the circulating flue gas injection port 19a. Can be sprayed. As a result, the water content of the waste can be evaporated so that the grate 30 and 31 of the first stage grate group 3a do not ignite while keeping the temperature of the furnace 4 low. There is also the advantage that the flame center is controlled to the center and posterior stages of the grate 30, 31 according to design requirements.

Details the benefits of using circulating flue gas. Due to the low water content, when incinerating highly volatile and low melting point solid waste, the entire furnace 4 is in the high temperature region. Therefore, when the solid waste passes through the supply grate 2, most of its external moisture evaporates. The solid waste that has entered the high temperature furnace 4 easily reacts with hydrogen at high temperature. When the volatile substance rapidly volatilizes and is rapidly burned, combustion is likely to occur in the grate of the first stage grate group 3a. Further, there is a concern that the fire spreads to the supply grid 2 and the supply hopper 1 ignites. In this respect, in the grate combustion system 101 according to the modified example of the embodiment, the circulating flue gas can be supplied to the grate 30 and 31 of the first stage grate group 3a via the circulating flue gas flow path 19. .. As a result, the ignition of the grate 30 and 31 of the first stage grate group 3a can be suppressed.

Sulfur and chlorine are present in the circulating flue gas. Therefore, measures may be taken to overcome metal corrosion caused by sulfur and chlorine. High grade steel may be used for the gas contact surface of the circulating flue gas flow path 19. There is an advantage that a high advantage can be obtained by a slight cost increase. For example, a corrosion prevention coating may be applied to the gas contact surface of the circulating flue gas flow path 19. The circulating flue gas flow path 19 may be provided with a filter that dams at least one of sulfur and chlorine, or a filter that decomposes them.

As shown in FIG. 7, the steam injection port 21 may be provided above the first stage grate group 3a.

In the grate combustion system 101 of the modified example, the amount of air blown to the air chambers 7a to 7e is individually adjusted by providing a plurality of blowers 18. However, the present disclosure is not limited to this, and similar air volume adjustment may be realized by providing another air volume adjustment mechanism such as a variable flow rate valve.

Further supplementing the embodiments described above, the inventor of the present application has independently focused on the following as the background of the present technical field. Solid waste is generated in people's lives and production processes and cannot be used directly as a production resource. Solid waste includes household waste, industrial waste, biomass and the like. Improper treatment of solid waste causes secondary pollution to the environment. Not only that, it poses a great threat to human health. As people's living standards improve and the development of civilization accelerates, waste classification becomes more detailed and the calorific value of combustible waste continues to increase. Major waste treatment methods at home and abroad include landfill, anaerobic, gasification, or incineration. However, each of the above waste treatment methods has drawbacks. For example, the drawbacks of landfill and anaerobic treatment are that they are inefficient, occupy a lot of land and cause secondary pollution such as sewage and odors. For example, the drawbacks of gasification are that explosive gas is likely to be generated, safety cannot be guaranteed, and gasification efficiency is low. For example, the drawback of incinerator is that a pure air-cooled grate for incineration cannot be used after the calorific value has increased to 2000 kcal / kg or more. The pure air-cooled grate is required to be improved in terms of incineration of the grate and charring of the furnace 4. In particular, there is an increasing need for a grate structure and a combustion system suitable for high heat resistance that can withstand a calorific value exceeding 2000 kcal / kg. The grate combustion system 100 of the embodiment has been variously improved to meet such needs.

The inventor of the present application pays unique attention to the fact that there are some problems when the low calorific value of the object to be processed exceeds 2000 kcal / kg. For example, the existing air-cooled grate cannot operate normally, the material of the existing air-cooled grate cannot withstand the high temperature under high calorific value combustion, the thermal expansion of the existing grate is not effectively controlled, and it is local. In the high temperature region, when the object to be treated after melting leaks from the air outlet, it is cooled and condensed, and this condensed body has a series of problems such as blocking the movement of the sliding grate. These problems were obtained by the original attention of the inventor of the present application. In addition, the movable water pipe and the static water pipe of the existing water-cooled grate are not sealed, and problems such as rust on the water pipe due to hot water leakage during operation and high humidity in the operating environment can be solved. It also has the advantages of low flash point, high volatility, and easy tempering of solid waste with high calorific value. In embodiments, these various advantages are provided.

1 Supply hopper 2 Supply grate 3 Grate device 3a First stage grate group 3f Front end 3r Rear end 4 Furnace 4a Front wall 4b Rear wall 4c Tail end 5 Secondary air injection device 6 Auxiliary combustion device 7 Primary air intake and Ash slag collecting device 7a-7e Air chamber (primary air chamber)
8 Steel support structure 17 Air pipeline 17a Predetermined branch pipeline 18 Blower (fan)
19 Circulating flue gas flow path 19a Circulating flue gas injection port 19q Double nozzle 20 Control device 21 Steam injection port 30 Grate (air / water mixed double cooling type fixed grate)
30a grate plate 31 grate (pure air-cooled sliding grate)
31a 1st row sliding grate 31b 2nd row sliding grate 31c 3rd row sliding grate 31d 4th row sliding grate 40 Drive 41, 41a, 41b Hydraulic cylinder 71 Primary air 72 With leaked ash Slug 73 Slug after combustion 100, 101 Grate combustion system Ds Movable distance (stroke distance)
L Length dimension W Width dimension θ1 Tilt angle θ2 Cutting edge angle hg Material Rolling guide wall height

Claims (18)

With a furnace
The grate device installed in the furnace and
Equipped with
The grate device is
Equipped with multiple grate stacked in a staircase so as to build a multi-stage grate group,
The plurality of grate is a grate combustion system including a grate having a column-integrated structure having a grate plate having an integrally continuous shape in the row direction. The plurality of grate are stacked in a staircase pattern so as to form a multi-stage grate group including each of the plurality of grate.
A plurality of air chambers provided below each of the multiple stages of grate groups, and
A blower device that communicates with each of the plurality of air chambers and is constructed so that the amount of air blown to each of the plurality of air chambers can be adjusted so as to make the amount of air blown to each of the plurality of air chambers different from each other.
The grate combustion system according to claim 1. The plurality of grate includes a plurality of sliding grate which are overlapped with the row-integrated grate and each of which is reciprocally displaced.
The grate device is
Front and rear ends,
A plurality of hydraulic cylinders that reciprocate back and forth between the plurality of sliding grate and
A hydraulic tank connected to the plurality of hydraulic cylinders,
Equipped with
The grate combustion system according to claim 1 or 2, wherein the hydraulic tank is arranged only on the side of the front end portion of the grate device. The row-integrated grate is installed as a fixed grate that is at least water-cooled.
The grate device further includes a pure air-cooled sliding grate that is superposed on the fixed grate and is constructed in a sliding manner that reciprocates back and forth and is cooled only by air among air and cooling water. The grate combustion system according to any one of 3. The grate combustion system according to claim 4, wherein the stroke distance when the pure air-cooled sliding grate is displaced back and forth back and forth is 200 mm to 450 mm. The row-integrated grate is constructed as an air / water-cooled mixed double-cooling grate that has a cooling water channel inside and is double-cooled by water cooling and air cooling.
The grate device comprises a plurality of grate groups.
Each of the plurality of grate groups includes a plurality of grate modules arranged in a staircase pattern.
Each of the plurality of grate modules
The column-integrated grate, which is an air / water-cooled mixed double cooling type,
A pure air-cooled grate that is stacked on the column-integrated grate and cooled only by air, which is either water-cooled or air-cooled.
The grate combustion system according to claim 1. The grate combustion system according to claim 6, wherein in each of the plurality of grate modules, the row-integrated grate is superposed directly above the pure air-cooled grate. The plurality of grate are directly overlapped with each other, and they are overlapped with each other.
The grate combustion system according to any one of claims 1 to 7, wherein the height of the material rolling guide wall in the plurality of grate is 400 mm to 800 mm. The grate combustion system according to any one of claims 1 to 8, wherein the angle formed by each of the plurality of grate with respect to the horizontal plane is 18 to 29 degrees. The grate combustion system according to any one of claims 1 to 9, wherein the cutting edge angle of each of the plurality of grate is 0 to 5 degrees. The row-integrated grate is constructed as an air / water-cooled mixed double-cooling grate that has a cooling water channel inside and is double-cooled by water cooling and air cooling.
The grate combustion system according to any one of claims 1, 9 and 10, wherein the height dimension of the row-integrated grate is 100 mm to 150 mm. The plurality of grate further includes a pure air-cooled grate which is superposed on the row-integrated grate and is cooled only by air among water-cooled and air-cooled.
The grate combustion system according to any one of claims 1 and 9 to 11, wherein the height dimension of the pure air-cooled grate is 120 mm to 200 mm. The grate device comprises a first-stage grate group that is composed of a part of the grate among the plurality of grate and is closest to the front end of the grate device.
The wind chamber provided below the first stage grate group and
A nozzle that communicates with the air chamber and supplies a mixed gas of air and circulating flue gas to the air chamber.
The grate combustion system according to any one of claims 1 to 12, further comprising. The grate device comprises a first-stage grate group that is composed of a part of the grate among the plurality of grate and is closest to the front end of the grate device.
The grate combustion system according to any one of claims 1 to 12, wherein a steam injection port for injecting steam is provided above the first stage grate group. The grate device comprises a first-stage grate group that is composed of a part of the grate among the plurality of grate and is closest to the front end of the grate device.
The grate combustion system according to any one of claims 1 to 12, wherein a circulating flue gas injection port is provided above the first stage grate group. The grate combustion system according to any one of claims 1 to 15, further comprising an auxiliary combustion device provided at the tail end of the furnace. At least one of an adiabatic path, an air-cooled furnace, and a water-cooled furnace is provided on the side wall of the furnace.
When the calorific value range of the solid waste treated in the furnace is 1000 kcal / kg to 1800 kcal / kg, an adiabatic furnace is provided.
When the calorific value range of the solid waste treated in the furnace is 1801 kcal / kg to 2500 kcal / kg, an air-cooled furnace is provided.
A water-cooled furnace is provided when the calorific value range of the solid waste treated in the furnace is 2501 kcal / kg to 7000 kcal / kg.
The grate combustion system according to any one of claims 1 to 15. In the furnace, a plurality of row-integrated fixed grate having a grate plate having a continuous shape in the row direction are arranged in a stepped manner with a vertical spacing from each other. A combustion step in which the solid waste on the row-integrated fixed grate is burned while stirring by reciprocating the sliding grate arranged in the above.
When the solid waste is burned in the combustion step, air is sent from the back surface side of the row-integrated fixed grate and the sliding grate while cooling the row-integrated fixed grate in a water-cooled manner. A cooling step for air-cooling the row-integrated fixed grate and the sliding grate,
A grate burning method.

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