JPS6021606Y2 - Low NO↓x heat sintering equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to the structure of a combustion device that can effectively reduce nitrogen oxides in a combustion furnace.

Nitrogen oxides (hereinafter abbreviated as NOx) contained in exhaust gas discharged from various combustion devices such as boilers cause air pollution, and efforts are being made to reduce them.

Methods for reducing this can be classified into the following methods.

(a) A multistage air supply method in which the amount of air supplied to the burner section is set to be less than the theoretical amount of air to form a primary combustion region, and the insufficient air is supplied to the downstream side of this region to make the combustion reaction multistage.

(b) Combustion in which multiple burners are provided, the air ratio (the ratio of the amount of air actually used to the theoretical amount of air) is set unevenly for each burner, and burners with excess fuel and burners with insufficient fuel are mixed. Method.

(C) An exhaust gas recirculation method in which the exhaust gas generated by combustion is recirculated to the burner section and mixed with combustion air, fuel, etc.

(d) A method in which the flame in the burner is divided and a single burner is operated with an air ratio bias.

etc.

However, in the methods shown above, if the low NOx combustion is strengthened, problems such as flame instability, increased amount of soot plugging, and increase in by-products such as CO will occur.
There are certain limits to this.

In addition, in the conventional method, there is insufficient mutual interference between the burner flame that burns with low oxygen combustion and the burner flame that burns with a theoretical air amount, and the combustion gas of these two burners is insufficiently mixed, so the amount of NOx produced is reduced. There was a tendency for the combustion efficiency to decrease significantly compared to the decrease.

The same thing can be said about the case of mixing of exhaust gas and mixing of air for combustion of unburned materials due to afterburning.

The purpose of this invention is to perform excessive fuel combustion and combustion with an air amount close to the stoichiometric air amount, and when reducing NOx with the intermediate products produced by excessive fuel combustion, the furnace structure is designed to achieve good mixing of the intermediate products. and, if necessary, eliminate exhaust gas contamination,
It is an object of the present invention to provide a furnace structure that can also be used for supplying air for afterburning.

In short, this idea is based on the idea that a unit member for injecting combustion air, fuel, etc. into the furnace is mounted on a furnace, and reducible intermediate products,
It is constructed to ensure good mixing of combustion air, etc.

Embodiments of this invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall view of the boiler, showing the furnace 21 of the boiler 20.
A state in which the unit member 22 is placed inside the frame is shown.

Figure 2 shows the details of this unit member, including multiple water pipes 4.
The refractory material layer 11 formed around the water pipe 4 forms a wood pipe wall, and the entire unit member 22 is formed as a columnar body.

Reference numeral 10 indicates a stud formed on the outer wall of the water pipe to facilitate the formation of the refractory material layer.

The inside of the unit member surrounded by the wood pipe wall is a combustion air passage, and a fuel pipe 6 is disposed within this passage.

When this unit member is placed in a furnace, an air injection lower is formed on the upper surface.

For this reason, it is preferable that the upper surface portion is configured to use tie bars 12 instead of wood pipes so that the air injection ports can be easily formed.

Furthermore, an opening like a conventional burner port can be easily formed by bending the tube.

Reference numeral 8 denotes a fuel injection pipe branched from the fuel pipe 6, and is erected approximately at the center of the air injection lower.

One or more of the unit members 22 formed as described above are inserted through the boiler furnace wall and arranged in the furnace 21 so that the racks are substantially perpendicular to the flow of combustion gas.

In this case, it is best to use a group of wood pipes that are slightly inclined to improve the flow of water inside the water pipes.

In the above device, the supply water W is passed through the water pipe 10 to protect the unit member 22 itself from the high heat in the furnace, and the fuel F is combusted by the combustion air A in the part consisting of the air injection lower and the fuel injection pipe 8. This part is used as a reduction burner by controlling the amount of combustion air supplied to the combustion air to be equal to or less than the theoretical amount of air.

In other words, the NOx generated by combustion in the main burner 1 with an air amount close to the theoretical air amount is removed from the unit member 22.
The reduction treatment is performed using highly reducing intermediate products such as CN and NH2 generated in the reduction burner.

In this case, a large number of reduction burners are arranged so as to be perpendicular to the gas flow of the boiler furnace, so that the intermediate products and NOx are mixed well and the reduction process is promoted.

Subsequently, the unburned components contained in the combustion gas are combusted by the combustion air supplied from the after-air board 3, and after greatly reducing the unburned components content in the exhaust gas, they are discharged to the outside of the system.

In the above embodiments, the unit member 22 has been described as being for installing a reduction burner, but the unit member 22 is not limited to this; it can also be used for installing a main burner, or by eliminating the fuel injection port 8, it can be used for installing an after-air port. Those skilled in the art can easily imagine that it can also be used.

By implementing this idea, intermediate products, NOx-containing exhaust gas, combustion air, etc. can be mixed well, and NOx
This has the effect of greatly improving the reduction rate.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a combustion device according to this invention, and FIG. 2 is a perspective view of a unit member. 4...Water pipe, 7...Air injection port, 8.
...Fuel injection pipe, 11...Refractory material layer, W
...Water supply, A...Combustion air, F...
····fuel.

Claims (1)

[Claims for Utility Model Registration] 1. Air passes through an interior surrounded by a heat-resistant wall, and one or more air injection ports are formed on this wall, and a fuel injection pipe is placed in the center of the air injection port. A low NOx combustion device, in which one or more of the unit members are positioned in a furnace of a combustion device across a frame. 2. The low NOx combustion device according to claim 1 of the utility model registration claim, in which the heat-resistant wall is composed of a wood pipe wall made of a plurality of wood pipes, and a heat-resistant material layer formed on the wood pipe wall surface. .