JPH09296927A - Secondary combustion gas feed mechanism of garbage incinerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce generation of NOx by dispersely providing secondary combustion gas feed nozzles with different feed gas flow velocity to the secondary combustion region. SOLUTION: A plurality of secondary combustion gas feed nozzles 14 to feed the secondary combustion gas to the combustion gas generated in a main fuel chamber 3 are dispersely provided in the circumferential direction of a furnace wall in a garbage incinerator. The secondary combustion gas feed nozzles 14 of two kinds of large diameter nozzle and small diameter nozzle are alternately provided in the circumferential direction of the furnace wall. The gas to be fed from the nozzle of larger diameter is large in volume but low in flow velocity, and burned relatively in the vicinity of the nozzle, while the gas to be fed from the nozzle of smaller diameter is small in volume but high in flow velocity, and burned on the relatively remote side from the nozzle, realizing the thick/thin combustion. As a result, the region to perform the combustion reaction by the secondary combustion gas is dispersed in the far and near direction along the gas feeding direction by the feed nozzle of the secondary combustion gas, and generation of the region of combustion at extremely high temperature can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plurality of secondary combustions for supplying secondary combustion gas to a secondary combustion zone for further burning unburned gas generated by combustion of an incineration object in the main combustion zone. The present invention relates to a secondary combustion gas supply mechanism in a refuse incinerator equipped with a gas supply nozzle.

[0002]

2. Description of the Related Art A secondary combustion region is provided for completely burning exhaust gas containing unburned gas after primary combustion in a main combustion chamber,
A secondary combustion gas supply nozzle for supplying combustion gas is provided in this secondary combustion region to completely combust the exhaust gas passing through this region. Here, in the secondary combustion gas supply mechanism of the conventional refuse incinerator, a plurality of secondary combustion gas supply nozzles having the same diameter are provided in the flue forming the secondary combustion region so as to face or substantially orthogonal to the gas flow of the combustion gas. The jets from the secondary combustion gas supply nozzles are arranged in parallel at regular intervals in the direction so that the flow velocity is uniform.

[0003]

However, according to the above-mentioned conventional secondary combustion gas supply mechanism for the refuse incinerator, the combustion reaction region by the supplied secondary combustion gas is located in the central portion in the secondary combustion region. There is a problem that it is difficult to reduce the amount of NOx produced as a result of being concentrated in a certain area and burning at an extremely high temperature in that area. An object of the present invention is to eliminate the above-mentioned conventional disadvantages.

[0004]

In order to achieve this object, the first characteristic constitution of the secondary combustion gas supply mechanism of the refuse incinerator according to the present invention is as described in claim 1 of the scope of claims. The secondary combustion gas supply nozzle is configured to disperse and supply different supply gas flow velocities to the secondary combustion region. In the second characteristic configuration, as described in claim 2 of the scope of the claims, the secondary combustion gas supply nozzles are dispersed and arranged with different nozzle diameters of the secondary combustion gas supply nozzles. It is in. A third characteristic configuration is, as described in claim 3 of the scope of the claims, that the secondary combustion gas supply nozzle is provided with oxygen containing secondary combustion gas supplied from each of the secondary combustion gas supply nozzles. The point is that they are distributed in different amounts. A fourth characteristic configuration is, as described in claim 4 of the scope of the claims, configured such that the secondary combustion gas supply nozzles are dispersedly supplied with different supply gas flow directions with respect to the secondary combustion region. There is a point. A fifth characteristic configuration is, as described in claim 5 of the scope of the claims, that the secondary combustion gas supply nozzle is composed of a double cylinder of an inner nozzle and an outer nozzle covering the inner nozzle and the outer nozzle is The secondary combustion gas supplied from the inner nozzle has a high oxygen concentration and is supplied.

The operation will be described below. According to the first characteristic configuration, the region in which the secondary combustion gas supplied to the secondary combustion region undergoes combustion reaction is dispersed in the perspective direction along the supply direction by the secondary combustion gas supply nozzle. Therefore, the generation of an extremely high temperature burning region is prevented. According to the second characteristic configuration, since the nozzle diameters of the secondary combustion gas supply nozzles are made different and distributed, the flow velocity of the gas supplied from each secondary combustion gas supply nozzle is different and the diameter is large. The amount of gas supplied from the nozzle is large, but the flow velocity is low, and it burns relatively near the nozzle, and the gas supplied from the nozzle with a small diameter is small, but the flow velocity is high and it burns relatively far from the nozzle. Combustion can be realized, and as a result, the region in which the secondary combustion gas supplied to the secondary combustion region undergoes combustion reaction is dispersed in the perspective direction along the supply direction by the secondary combustion gas supply nozzle, The generation of an extremely high temperature burning region is prevented. According to the third characteristic configuration, since the oxygen content of the secondary combustion gas supplied from each of the secondary combustion gas supply nozzles is made different and dispersed, the combustion gas is supplied from the nozzle having a large oxygen content. Is supplied and the area where combustion gas is supplied from a nozzle with a low oxygen content can realize rich-lean combustion, and as a result, the area where combustion reaction occurs due to the secondary combustion gas supplied to the secondary combustion area As a result of being dispersed, the generation of a region that burns at extremely high temperatures is prevented. According to the fourth characteristic configuration, since the supply gas flow direction is differently supplied to the secondary combustion region, the combustion reaction region in the secondary combustion region is dispersed, and an extremely high temperature combustion region is generated. Will be blocked. According to the fifth characteristic configuration, by covering the secondary combustion gas having a high oxygen concentration supplied from the inner nozzle with the secondary combustion gas having a low oxygen concentration supplied from the outer nozzle, Thus, the combustion reaction region is dispersed and the generation of a region where extremely high temperature combustion occurs is prevented.

[0006]

EFFECTS OF THE INVENTION According to the present invention, the incineration of waste can be performed while promoting the combustion reaction in the secondary combustion region, while preventing the generation of the region of extremely high temperature combustion to reduce the generation amount of NOx. A secondary combustion gas supply mechanism for the furnace can now be provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments will be described below. In the refuse incinerator, as shown in FIG. 1, the material to be incinerated (such as municipal waste) put into the hopper 2 is put into the main combustion chamber 3 which constitutes the primary combustion region by the reciprocating drive of the pusher 1 provided at the lower part thereof. The ash that has been incinerated in the main combustion chamber 3 is collected in the ash pit 4.

The main combustion chamber 3 has a drying zone A for drying the incineration object and heating it to a temperature near the ignition point, a combustion zone B for burning the dried incineration object, and a post-combustion zone for ashing the incineration object. C is arranged stepwise from the upper side to the lower side, and air supply means 12 for supplying the primary combustion air from the lower side is provided. In the dry zone A, the combustion zone B, and the post-combustion zone C, fixed grate and movable grate are alternately arranged in the arrangement direction, and the relative movement of the grate in the arrangement direction stirs and conveys the dust. It is composed of a stoker type carrier device 5. Further, a combustion control means (not shown) provided with a computer for adjusting the transport speed of the pusher 1 or the transport device 5, or the air supply amount from the air supply means 12 for supplying the primary combustion gas, and performing stable combustion. ) Is provided.

In the upper part of the main combustion chamber 3 and in the space above the combustion zone B, there is provided a flue 13 which serves as a secondary combustion region 130 in which exhaust gas after primary combustion is completely combusted. A waste heat boiler 9 is provided on the downstream side of the exhaust gas, is taken out in the form of steam by the heat energy of the exhaust gas, is superheated by the combustion type superheater 16 and is then supplied to the turbine / generator 10, while the flue 13 Further, an exhaust gas treatment facility 11 including an electric dust collector or the like is provided on the downstream side to remove dust and harmful gas and then exhaust the gas from the chimney.

On the side wall surface 30 on the inlet side of the flue 13, a plurality of secondary combustion gas supply nozzles 14 for supplying the secondary combustion gas to the combustion gas generated in the main combustion chamber 3 are dispersedly arranged in the circumferential direction of the furnace wall. Is provided. Further, the secondary combustion gas supply nozzle 14
There is provided a blower fan and a damper for adjusting the supply amount of the secondary combustion gas, and a combustion air supply amount adjusting means 15 including a control circuit for controlling the opening degree of the damper.

Here, as shown in FIG. 2, the secondary combustion gas supply nozzle 14 has nozzles of two kinds of diameters, a large diameter nozzle 14a and a small diameter nozzle 14b, which are alternately provided in the furnace wall circumferential direction. is there. Therefore, a large amount of gas is supplied from a nozzle with a large diameter, but the flow velocity is low and it burns relatively near the nozzle, and a small amount of gas is supplied from a nozzle with a small diameter, but the flow velocity is high and the nozzle is relatively large. It is possible to realize rich-lean combustion that burns on the remote side, and as a result, the region where the secondary combustion gas supplied to the secondary combustion region undergoes combustion reaction is dispersed in the perspective direction along the supply direction by the secondary combustion gas supply nozzle. As a result, the generation of an extremely high temperature burning region is prevented. As a result, the amount of NOx generated can be reduced. Generally, in order to completely burn the gas containing carbon monoxide after the primary combustion, it is necessary to sufficiently supply and stir oxygen at a high temperature of about 850 ° C. or more and to secure a sufficient burning time. However, considering that there is a sufficient amount of unreacted residual oxygen supplied in the primary combustion region, as the secondary combustion gas supplied from the secondary combustion gas supply nozzle exclusively to promote the stirring effect, Combustion type superheater 16 having an oxygen content of 3 to 4% and a temperature of about 300 ° C.
The exhaust gas of is used. In other words, the secondary combustion gas mainly fulfills the function of stirring and mixing the unburned gas generated in the primary combustion region and the residual oxygen, and maintains the secondary combustion region temperature in the range of about 800 ° C to 1000 ° C. It also reduces the amount of NOx produced by providing a cooling function that avoids high temperatures.

Another embodiment will be described below. In the above embodiment, as the secondary combustion gas supply nozzle 14,
A nozzle in which two types of nozzles, a large diameter nozzle 14a and a small diameter nozzle 14b, are alternately provided in the furnace wall circumferential direction, that is,
Although the secondary combustion gas supply nozzles having different nozzle diameters and dispersedly arranged have been described, the configuration of the secondary combustion gas supply nozzles 14 is not limited to this, and the secondary combustion gas supply nozzles 14 may have a plurality of different diameters such as large, medium and small. The nozzles may be arranged alternately.

The secondary combustion gas supply nozzle 14 is constructed so as to disperse and supply the supply gas to the secondary combustion region at different flow velocities, and a region where the secondary combustion gas supplied to the secondary combustion region undergoes a combustion reaction. However, the secondary combustion gas supply nozzle may be configured to be dispersed in the perspective direction along the supply direction to prevent the generation of an extremely high temperature combustion region. Specifically, as shown in FIG. 3, nozzles 14c having the same diameter are arranged in the circumferential direction of the furnace wall, and the secondary combustion gas is supplied so that the flow velocity of the secondary combustion gas alternates in the arrangement direction of the nozzles 14c. become.

The secondary combustion gas supply nozzles 14 are arranged so as to have the same diameter, and the secondary combustion gas supplied from each of the nozzles is made to have a different oxygen content so as to be dispersed. A region where gas is supplied and a region where combustion gas is supplied from a nozzle with a low oxygen content realizes rich / lean combustion, and as a result, a region where combustion reaction occurs due to the secondary combustion gas supplied to the secondary combustion region. May be dispersed so as to prevent the generation of an extremely high temperature burning region. Specifically, as shown in FIG. 4, the nozzles 14d for supplying the exhaust gas of the combustion type superheater 16 and the nozzles 14e for supplying the air may be alternately arranged. From the viewpoint of different oxygen contents, By changing the mixing ratio of the exhaust gas and air of the combustion type superheater 16, it is possible to supply in multiple stages.

Further, the secondary combustion gas supply nozzles are arranged with different nozzle diameters in a dispersed manner, and air is supplied from a large diameter nozzle and exhaust gas of the combustion type superheater 16 is supplied from a small diameter nozzle, and a large diameter nozzle. The oxygen content of the secondary combustion gas supplied from each of the nozzle and the small-diameter nozzle may be different from each other to realize the rich and lean combustion. The secondary combustion gas supply nozzle 14 is configured to disperse and supply different supply gas flow directions to the secondary combustion region,
The combustion reaction region within the secondary combustion region may be dispersed to prevent the generation of a region where extremely high temperature combustion occurs.
Specifically, as shown in FIG. 5, it can be realized by arranging adjacent nozzles at an angle in the vertical direction.

As shown in FIG. 6, the secondary combustion gas supply nozzle 14 has a double structure so that the exhaust gas of the combustion type superheater 16 is supplied from the outer nozzle 14g and the air is supplied from the inner nozzle 14f. Then, the air supply side nozzle 14
f and the supply speed from the exhaust gas supply nozzle 14g may be different from each other. In this case, the distributed combustion can be realized by the two-layer flow in which the air flow is covered with the exhaust gas of low oxygen concentration from the outside while the amount of oxygen required for the secondary combustion can be adjusted. In this case, as long as there is a difference in the oxygen concentration of the secondary combustion gas supplied from the inner nozzle 14f and the outer nozzle 14g, the combination is not limited to air and exhaust gas.

Further, these may be appropriately combined and arranged not only in a line in the circumferential direction of the furnace wall but also in multiple stages, and the nozzles may be arranged in a direction facing the exhaust gas flow or in a direction substantially orthogonal thereto. Just place it. Further, the nozzles for the distributed supply are not only arranged alternately one by one, but a plurality of groups may be arranged alternately.
Further, as the secondary combustion gas, not only air but other gas may be used. For example, city gas as a supplementary combustion gas or the like, or this exhaust gas can be used for those provided with a combustion type superheater outside.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a garbage incinerator.

FIG. 2 is an explanatory view of a main part.

FIG. 3 is an explanatory diagram of a main part showing another embodiment.

FIG. 4 is an explanatory diagram of a main part showing another embodiment.

FIG. 5 is an explanatory view of a main part showing another embodiment.

FIG. 6 is an explanatory diagram of a main part showing another embodiment.

[Explanation of symbols]

 3 Main Combustion Area 14 Secondary Combustion Gas Supply Nozzle 130 Secondary Combustion Area A Dry Zone B Combustion Zone C Post-combustion Zone

Front Page Continuation (72) Inventor Shinji Ozaki 1-1-1 Hama, Amagasaki City, Hyogo Prefecture Kubota Technology Development Laboratory

Claims (5)

[Claims] 1. A plurality of secondary combustion gas supply nozzles for supplying secondary combustion gas to a secondary combustion region for further burning unburned gas generated by combustion of an incineration object in the main combustion region. A secondary combustion gas supply mechanism for a refuse incinerator, wherein the secondary combustion gas supply nozzles are configured to disperse and supply the secondary combustion gas at different flow rates of the supply gas to the secondary combustion region. 2. A plurality of secondary combustion gas supply nozzles for supplying secondary combustion gas to a secondary combustion region for further burning unburned gas generated by combustion of an incineration object in the main combustion region. A secondary combustion gas supply mechanism for a refuse incinerator, wherein the secondary combustion gas supply nozzles are dispersed in the secondary combustion gas supply nozzle with different nozzle diameters. 3. A plurality of secondary combustion gas supply nozzles for supplying secondary combustion gas to a secondary combustion region for further burning unburned gas generated by combustion of an incineration object in the main combustion region. In the waste incinerator, the secondary combustion gas supply nozzles are arranged in a dispersed manner by varying the oxygen content of the secondary combustion gas supplied from each of the secondary combustion gas supply nozzles. Combustion gas supply mechanism. 4. A plurality of secondary combustion gas supply nozzles for supplying secondary combustion gas to a secondary combustion region for further burning unburned gas generated by combustion of an incineration object in the main combustion region. A secondary combustion gas supply mechanism for a refuse incinerator, wherein the secondary combustion gas supply nozzles are configured to disperse and supply the secondary combustion region with different supply gas flow directions to the secondary combustion region. 5. A plurality of secondary combustion gas supply nozzles for supplying secondary combustion gas to a secondary combustion region for further burning unburned gas generated by combustion of an incineration material in the main combustion region. In the refuse incinerator, the secondary combustion gas supply nozzle is composed of a double cylinder of an inner nozzle and an outer nozzle covering the inner nozzle, and the oxygen concentration of the secondary combustion gas supplied from the inner nozzle to the outer nozzle is increased. A secondary combustion gas supply mechanism for a refuse incinerator that is configured to be supplied as a secondary combustion gas.