JP2002022124A - Stoker furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stoker furnace in which to-be-incinerated matters are efficiently dried in a drying step in stoker steps, an amount of air circulating in the incinerator is reduced as far as possible, and a high temperature is attained in the main combustion region. SOLUTION: A supply line 16 for supplying a high-temperature exhaust gas is provided in a wind box 4a of a stoker step 4 positioned nearest to a waste supply port 2, and the matters to be incinerated are dried by a mixed gas of air and the high-temperature exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stoker furnace used for incineration of incinerated materials such as municipal garbage and industrial waste, and more particularly, to increasing the drying efficiency in a combustion chamber and incinerating the entire stoker furnace. It also relates to those that also improve efficiency.

[0002]

2. Description of the Related Art Conventionally, a stoker furnace having a plurality of stoker stages having a wind box below has been widely used as an incinerator for incinerating objects to be incinerated such as municipal waste and industrial waste. In this stoker furnace, a drying stoker, a combustion stoker, and a post-burning stoker, which are inclined rearward, are arranged in a staircase in the front-rear direction in the lower part of the combustion chamber. The ash outlet is provided at the outlet of the fuel cell, and the secondary combustion chamber is provided above the combustion chamber.

[0003] In the stoker furnace having this configuration, the incineration material supplied from the dust supply port is sequentially dried from the dust supply port to the drying stage.
It flows over each of the storage stages of the combustion stage and the post-combustion stage, and is dried and further burned. The incineration material supplied from the dust supply port to the front of the drying stage is dried in the drying stage by primary air from below and radiant heat in the furnace. In particular, since about 50% of water is contained in municipal waste, evaporation and partial pyrolysis of this water are performed in this drying stage. Thereafter, the combustion stage ignites the refuse with the supplied primary air and burns volatiles and fixed carbon. The post-combustion stage burns unburned components (mainly fixed carbon components) that have passed without being burned until they completely become ash. Further, the combustion gas generated in the combustion chamber is mixed with the secondary air to reach the secondary combustion chamber, where it is burned.

A wind box is provided below each of the stoker stages, and outside air is introduced into the wind box using a blower or the like, and is supplied as primary air from a grate at each of the stoker stages. It has a structure. The primary air introduced into each stoker stage wind box is supplied from a common blower.

[0005]

The primary air supplied to the drying stage is for evaporating the moisture of the garbage and promoting ignition, but is only for taking in outside air with a blower. In order to dry garbage, it is necessary to blow a large amount over a large space. In particular, in the combustion of low-calorie refuse, primary air is heated to 250 ° C. and supplied, but an external primary air heating device is required. Therefore, as disclosed in Japanese Patent No. 2712017, what was mixed with outside air and discharged from the entire surface of the grate or the hearth was diverted, and the outside air and the combustion exhaust gas were mixed into all of the stoker-stage wind boxes. It is also conceivable to supply a mixed gas.

However, in order to supply the outside air as the primary air to evaporate and dry the moisture contained in the incineration material, it is necessary to supply a large amount of the primary air to the drying stage, which is not sufficient. A large dry space is also required. In this case, the equipment of the stove furnace increases in size, and the amount of gas circulating in the entire stove furnace increases. Also, when the exhaust gas is mixed with the primary air and heated to be supplied not only to the drying stage but also to the combustion stage, the amount of air circulating through the entire stove furnace is relatively large. As a result, the amount of air circulating in the combustion chamber becomes excessive, and the efficiency of the entire furnace decreases, for example, the oxygen ratio of air in the main combustion region decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. It is an object of the present invention to efficiently dry an incinerated material in a stoker-stage drying stage and to circulate in an incinerator. An object of the present invention is to provide a stoker furnace capable of reducing the amount of air as much as possible and raising the temperature of a main combustion zone.

[0008]

According to a first aspect of the present invention, there is provided a stoker furnace, wherein an object to be incinerated supplied from a refuse supply port is sequentially passed over a plurality of stoker stages having wind boxes below. In a stoker furnace for drying and burning while flowing, a high-temperature exhaust gas supply line is provided in the wind box of the stoker stage closest to the dust supply port. According to the first aspect, since the mixed gas of the high temperature exhaust gas and the outside air is used instead of the outside air as the primary air to be supplied to the stoker stage wind box closest to the dust supply port, the temperature of the air supplied from the wind box is reduced. And the incineration material is dried efficiently. Here, the stoker stage closest to the trash supply port is usually a drying stage, and when there is one wind box provided in this drying stage, a mixed gas is supplied to this wind box and provided in the drying stage. If two or more wind boxes are provided, the mixed gas is supplied to at least the front wind box.

[0009] The stoker furnace according to the second aspect is the first aspect.
Wherein the plurality of stoker stages include a drying stage, a combustion stage, and a post-combustion stage, and the supply line sends the high-temperature exhaust gas extracted from the gas atmosphere above the post-combustion stage to a wind below the drying stage. It is a device to supply to the box. According to the second aspect, the gas in the upper part of the post-combustion stage is relatively clean after the corrosive gas has been blown off, and has a high temperature. When mixed, the drying of the incinerated material in the drying stage is accelerated, and the corrosion of the exhaust gas piping and the wind box reaching the drying stage wind box is reduced.

[0010] The stoker furnace according to the third aspect is the first aspect.
(2) In the apparatus according to (2), the amount of the high-temperature exhaust gas supplied through the supply line is controlled based on a detection unit that detects a combustion start position of the incinerated material. According to the third aspect, by detecting the burning start position of the incinerated material at the storage stage closest to the dust supply port,
The degree of drying of the material to be incinerated in the storage stage can be determined, and the mixing ratio between the high-temperature exhaust gas and the primary air can be appropriately controlled so that the drying becomes appropriate.

[0011] The stoker furnace according to the fourth aspect is the first aspect of the invention.
Or in 2 or 3, the apparatus for supplying oxygen-enriched air to the wind boxes other than the stoker stage closest to the dust supply port. According to the fourth aspect, by providing a supply means for supplying oxygen-enriched air to wind boxes other than the stoker stage closest to the refuse supply port, the amount of air circulating in the entire furnace is reduced, and the temperature in the main combustion chamber is reduced. Can be higher.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically showing a cross section of a side surface of a stoker furnace according to the present invention.

In FIG. 1, a storage furnace 1 is provided with a refuse supply port 2 and a pusher-type refuse transporter 3, followed by a main combustion chamber 7, and a secondary combustion chamber 8 above it. Is provided, and is configured to continue to the exhaust pipe 9. Garbage supply port 2
Is an open type, and the garbage transporter 3 following the ITV 24 monitors the main combustion chamber 7, especially the post-combustion stage 6 near the end of combustion.
Controls the transport speed, and enables the stable operation of the stove furnace.

The main combustion chamber 7 is provided in a stair-like manner in which the stocker stages 4, 5, and 6 extend downward and incline in order from the dust supply port 2. Each of the storage means 4, 5, and 6 comprises a drying stage 4, a combustion stage 5, and a post-combustion stage 6 in total, starting from the one closest to the dust supply port 2. The incinerated material D supplied to the front end of the
It is transported sequentially to the combustion stage 5 and the post-combustion stage 6.

The drying stage 4, the combustion stage 5 and the post-combustion stage 6
Have wind boxes 4a, 5a, 6a below them,
From there, the primary air is supplied. In particular, the hot box 4a of the drying stage 4 is supplied with the hot gas extracted from the hot gas inlet 15 installed at the upper part of the post-combustion stage 6 through the hot gas pipe (hot exhaust gas supply line) 16. Is provided with an ejector 14.

Each of the stocker stages 4, 5, and 6 is provided with a movable grate (not shown) and a fixed grate (not shown) alternately. The incineration material D supplied from the port 2 can be sequentially transported backward on the drying stage 4, the combustion stage 5, and the post-combustion stage 6 while stirring the incinerated material D supplied from the mouth 2. The feed speed of the incinerated material in each of the storage stages 4, 5, 6 can be arbitrarily controlled by the forward and backward moving speed of the movable grate.
A conveyor 29 is connected below the wind boxes 4a, 5a, and 6a.

Next, the primary air is supplied to the wind boxes 4a, 5a, 6a corresponding to the respective storage stages 4, 5, 6 by a primary air blower 13 by a primary air blower. 11 is performed. The supply amount is appropriately controlled by the control valve 12 or the like according to the combustion state in the main combustion chamber 7 and the supply condition of high-temperature air described later.

Here, in the drying stage 4, the high-temperature gas taken out from the high-temperature gas outlet 15 above the post-combustion stage 6 passes through a high-temperature gas pipe (high-temperature exhaust gas supply line) 16 and is set in the wind box 4 a. Wind box 4a from the ejector 14
Supplied within. When the air sent from the ejector air blower 19 passes through the ejector air air supply pipe 17 and blows out from the ejector 14, the hot gas in the upper part of the post-combustion stage 6 is sucked and supplied into the wind box 4a. The amount of the hot exhaust gas supplied into the wind box 4a is adjusted by the amount of ejector air controlled by the control valve 18. As a result, a mixed gas of high-temperature exhaust gas, ejector air and primary air is supplied to the drying stage 4.

Further, in the secondary combustion chamber 8, the secondary air
It is supplied from the next air inlet 20. With this secondary air, the unburned components contained in the combustion gas generated by the combustion in the combustion stage 5 and the post-combustion stage 6 are completely burned, and then discharged from the exhaust pipe 9.

By the way, an ITV (combustion start position detecting means) 2 provided near the boundary between the drying stage 4 and the combustion stage 5
Numeral 3 detects the combustion start position in the drying stage 4, and the detected image is transmitted to the image processor 25. Further, the temperature sensor-26 detects the internal temperature of the wind box 4 a of the drying stage 4. The controller (combustion start position control means) 27 to which these measurement data have been transmitted is sent to the drying stage 4.
Is controlled so as to keep the combustion start position at a constant. As a control method, the amount of high-temperature gas supplied through the ejector 14 is adjusted by changing the amount of ejector air by the control valve 18. Further, if necessary, the amount of primary air supplied from the primary air blower 13 is adjusted by the control valve 12. By appropriately performing these adjustments, the mixing ratio of the supplied high-temperature gas, the ejector air, and the primary air is adjusted, and the combustion start position in the drying stage is set to a predetermined fixed position. 4 and the connection between the combustion stage 5. At this time, the total amount of the mixed gas of the high-temperature gas, the ejector air, and the primary air supplied to the drying stage 4 is kept constant.
Is maintained within the set temperature range.

Next, the incineration process of the incineration object by the stoker furnace 1 having the above-described structure will be described below. Garbage supply port 2
The incinerated material such as municipal waste supplied onto the drying stage 4 through the air is mixed with the high temperature exhaust gas extracted from the post-combustion stage 6 and the outside air, for example, at a high temperature of 100 ° C. to 600 ° C. Dry with primary air. If the primary air causes the grate to become too hot, a water-cooled grate should be used. The drying stage 4 is a portion that evaporates the moisture of the garbage and promotes ignition, and the oxygen concentration does not matter relatively.
Since there is no problem due to the mixing of the high-temperature gas, the processing capacity of the drying stage 4 is improved by the high-temperature primary air, and the drying can be performed with a small amount of air. Next, the incineration material pushed out to the combustion stage 5 is burned by primary air in which high-temperature exhaust gas is not mixed. In this combustion stage 5,
The oxygen concentration of the primary air is important, and the outside air or oxygen-enriched air can incinerate the refuse at a high temperature with a small amount of air. The unburned matter pushed out to the post-combustion stage 6 is burned by the primary air not mixed with the high-temperature exhaust gas. Also in the post-combustion stage 6, the oxygen concentration of the primary air is important, and the refuse can be incinerated at a high temperature with a small amount of air by the outside air or the oxygen-enriched air. After this, the combustion stage 6
Since this portion generates high-temperature and relatively clean exhaust gas, when the high-temperature exhaust gas in this portion is supplied to the wind box 4a of the drying stage 4, efficient drying can be performed, and the hot gas pipe 16 and the wind box 4a can be efficiently dried. Corrosion can also be suppressed.

As described above, by drying and incineration of the incinerated material with a small amount of primary air, the gas amount in the entire furnace is reduced, the air ratio is reduced as a whole furnace, and the temperature of the main combustion zone is raised. As a result, efficient combustion can be achieved while suppressing the generation of trace contaminants such as DXN, and the furnace body and exhaust gas equipment can be made compact.

Next, a stoker furnace 101 according to another embodiment will be described with reference to FIG. FIG. 2 is a diagram schematically showing a cross section of a side surface of the stoker furnace according to the present invention.

The parts different from FIG. 1 are the drying stage 31 and FIG.
Combustion stage 3 in which combustion stage 5 and post-combustion stage 6 are combined into one
2, a stoker stage is formed, extracted from a high-temperature gas outlet 33 provided in the secondary combustion chamber 8, and passed through a high-temperature gas pipe 34 (high-temperature gas supply line). This is the point that has been introduced. The other parts are the same as those in FIG. 1, and the same reference numerals are given and the description thereof is omitted.

As shown in FIG. 1, the drying stage 3
The incineration material supplied to the front end of the first unit 1 is dried in a drying stage 31 by a mixed gas of high-temperature gas, ejector air and primary air supplied from a lower wind box 31a. Thereafter, in the combustion stage 32, the dried incineration material is completely burned, and in the secondary combustion chamber 8 above the main combustion chamber 7, unburned components contained in the combustion gas generated by the combustion in the combustion stage 32 are removed. After complete combustion, it is discharged from the exhaust pipe 9.

Although the inside of the secondary combustion chamber 8 is cooled by mixing the secondary air, the unburned portion contained in the combustion gas generated by the combustion in the combustion stage 32 is completely burned in the secondary combustion chamber 8. Therefore, when the exhaust gas in this portion is mixed with the primary air of the wind box 31a of the drying stage 31 because of relatively high temperature, drying is promoted, the air amount in the entire furnace is reduced, and the incineration material is efficiently reduced. Can be incinerated.

The embodiments of the present invention are not limited to the above embodiments, but may be modified as follows. (1) In FIG. 1, when the temperature of the hot gas to be supplied is relatively low, the hot gas can be supplied by providing a blower in the hot gas pipe without using an ejector. Good. (2) A plurality of, for example, two wind boxes may be arranged in series with respect to the drying stage 4 in FIG. In this case, high-temperature exhaust gas may be mixed only in the wind box closest to the dust supply port 2 or in the two wind boxes in the drying stage 4. (3) In FIG. 1, a plurality of stocker stages may be horizontally arranged in tandem.

[0028]

As described above, according to the stoker furnace of the first aspect, the stoker stage closest to the supply port is a portion for drying the burnable material and promoting ignition, and the wind of the stoker stage is When high-temperature exhaust gas is supplied to the box, the temperature of air blown up from the wind box increases, and drying is promoted. As a result, the drying efficiency of the stoker stage closest to the supply port increases, the amount of air blown from the wind box decreases, the air ratio in the main combustion area decreases, the temperature of the main combustion area increases, and efficient and space-saving combustion is performed. Can be realized.

According to the stoker furnace of the second aspect, since the gas atmosphere in the upper part of the post-combustion stage is high in temperature after the corrosive gas has flown, a relatively clean high-temperature gas is supplied to the stoker closest to the supply port. It can be mixed with the air in a step wind box.
Accordingly, since the corrosive gas is small, the corrosion of the wind box in the stoker stage closest to the gas piping and the supply port constituting the supply line is reduced.

According to the stoker furnace of the third aspect, when the combustion start position of the incinerated material is detected, the degree of drying of the incinerated material in the stoker stage closest to the supply port can be determined, and the high-temperature exhaust gas can be appropriately dried. To control the amount of circulation. This makes it possible to appropriately dry the incinerated material in the stoker stage closest to the dust supply port with a small amount of air.

According to the stoker furnace of the fourth aspect, by supplying the oxygen-enriched air to wind boxes other than the stoker stage closest to the dust supply port, the amount of air circulating in the entire furnace can be reduced. Thereby, the temperature in the main combustion chamber can be increased, and the combustion efficiency of the entire furnace can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a cross section of a side surface of a stoker furnace according to the present invention.

FIG. 2 is a diagram schematically showing a cross section of a side surface of another stoker furnace according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage furnace 2 Garbage supply port 4 Drying stage 4a Wind box 5 Burning stage 5a Wind box 6 Afterburning stage 6a Wind box 7 Main combustion chamber 8 Secondary combustion chamber 15 High temperature gas intake 16 High temperature gas pipe (supply line) 23 ITV (combustion start detection means) 27 Controller (combustion start position control means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masamitsu Takahashi 1-3-18 Wakihama-cho, Chuo-ku, Kobe City, Hyogo Prefecture Kobe Steel, Ltd.Kobe Head Office (72) Inventor Shoji Umezono Wakihama, Chuo-ku, Kobe City, Hyogo Prefecture 1-318, Kobe Kobe Steel, Ltd. Kobe Head Office (72) Inventor Hisanori Shimakura 1-3-18, Wakihama-cho, Chuo-ku, Kobe-shi, Hyogo F-term (reference) 3K061 HA03 HA17 HA21 HA27 3K065 AA02 AC01 CA15

Claims (4)

[Claims] 1. An incinerated material supplied from a garbage supply port is
In a stoker furnace for drying and further burning while sequentially flowing over a plurality of stoker stages having a wind box below, a supply line for high-temperature exhaust gas is provided in the wind box of the stoker stage closest to the dust supply port. And a stoker furnace. 2. The plurality of stoker stages include a drying stage, a combustion stage, and a post-combustion stage, and the supply line supplies hot exhaust gas extracted from a gas atmosphere above the post-combustion stage to the drying stage. 2. The air supply device is supplied to a lower wind box.
A stoker furnace according to item 1. 3. The stoker furnace according to claim 1, wherein an amount of the high-temperature exhaust gas supplied through the supply line is controlled based on a detection unit that detects a combustion start position of the incinerated material. 4. The stoker furnace according to claim 1, wherein oxygen-enriched air is supplied to the wind boxes other than the stoker stage closest to the dust supply port.