JP2766818B2 - Spray nozzle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray nozzle for mixing a liquid agent and a gas and spraying the mixture to the outside.
The present invention relates to a spray nozzle suitable for use as an injector for spraying a urea aqueous solution into a combustion chamber or an exhaust passage in order to remove water.

[0002]

2. Description of the Related Art Various methods have been proposed for reducing the concentration of nitrogen oxides (NOx) in exhaust gas in combustion equipment such as a boiler as much as possible. For example, JP-T-63-50208
No. 6 discloses a method in which a nitrogen oxide and urea are reacted by spraying an aqueous urea solution into exhaust gas to decompose the gas into nitrogen gas, carbon dioxide gas and water. According to this method, the removal rate of nitrogen oxides in a region where the temperature of the exhaust gas is high (hereinafter, referred to as a denitration rate) is achieved by only a relatively simple operation of spraying the urea aqueous solution into the exhaust gas without using a catalyst or the like. Can be easily improved. Conventionally, a so-called external mixing type nozzle is usually used for such a spray nozzle.

[0003] In the denitration apparatus of the above-mentioned method, when the liquid agent and the gas are mixed immediately before spraying, the liquid agent and the gas are sent to the mixing position using, for example, a double tube, so that the outer diameter of the tube is large. Become. However, in the case of a boiler, for example, water pipes are arranged at minute intervals along the outer wall, so that the spray nozzle must be inserted between the water pipes adjacent to each other and inserted into the boiler. When retrofitted, there is a problem that the operation of inserting the spray nozzle into the boiler becomes troublesome.

Further, when the optimum spray direction is shifted from the position where the spray nozzle can be inserted, it is conceivable to insert the spray nozzle obliquely or use a spray nozzle having a bent spray end only. Not only is the work cumbersome, but it is not very realistic because of the high installation accuracy required.

[0005]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, a main object of the present invention is to use a denitration apparatus for a boiler or other combustion apparatus to easily insert the apparatus into a furnace. An object of the present invention is to provide a spray nozzle capable of setting a spray direction to a desired direction.

[0006]

According to the present invention, there is provided, in accordance with the present invention, a method for producing nitrogen oxides (NO
A spray nozzle for spraying a urea aqueous solution into a combustion chamber or an exhaust passage of the combustion device in order to remove the urea solution, and for internally mixing and spraying a urea aqueous solution and a gas. To mix the external urea aqueous solution with the gas.
From the position where they meet to the inside of the combustion chamber or exhaust passage.
Opening at an end portion of the extension tube portion,
It has a slit-shaped spray port, and the extension pipe portion has a base end.
Has the same diameter over its entire length from the
The slit-shaped spray port extends in the axial direction of the extension tube portion.
This is achieved by providing a spray nozzle characterized in that it is open at an angle to the spray nozzle.

[0007]

[Function] As described above, after the liquid agent and the gas are internally mixed,
Introduce into the combustion chamber or exhaust passage by the extension pipe.
With this, the part to be inserted into the furnace wall can be made thin, and at the tip
Only the slit is opened with its inclination with respect to the axial direction.
By doing so, it is possible to spray in a desired direction without enlarging the tip , bending the nozzle, or installing the nozzle obliquely.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a preferred embodiment of the present invention. FIG. 1 is a partial side sectional view showing the configuration of a vertical heavy oil fired boiler and a nitrogen oxide removing apparatus to which the present invention is applied. The boiler 1 has a combustion chamber 2
And a heat exchange chamber 3 with a partition 4 and are connected by an upper through hole 4a. Here, although not shown, a large number of water pipes are arranged at appropriate places of the combustion chamber 2 and the heat exchange chamber 3. A burner 5 is provided at a lower position of the combustion chamber 2.
The exhaust gas generated here reaches the heat exchange chamber 3 via the upper through hole 4a and is discharged from an exhaust port (not shown).

An urea aqueous solution storage tank 8 connected to a pump 9 is located at an arbitrary position separated from the boiler 1.
Is provided. The pump 9 is connected to the mixing unit 10 in parallel.

The mixing unit 10 has a similar structure, and is controlled by a controller 11. Further, a mixing tank (not shown) is provided inside the mixing unit 10 so that the urea aqueous solution from the storage tank 8 and the water from the plant water supply pipe 12 are mixed.

The mixing unit 10 is connected in parallel to spray nozzles 13 and 14 provided at the ceiling of the combustion chamber 2 so as to penetrate the wall 1a of the boiler 1. A plant air supply pipe 15 is also connected to the spray nozzles 13 and 14 via a pressure regulating valve, a solenoid valve, a check valve, and the like. The fuel is injected from 14.

When the nitrogen oxide removing device is actually operated, the controller 11 loads the boiler 1 with the load, exhaust temperature, ammonia concentration, nitrogen oxide concentration, oxygen concentration, carbon monoxide concentration, flow rate and pressure of each pipe. The detection result by a sensor (not shown) for detecting the urea aqueous solution is input from the spray nozzles 13 and 14 into the combustion chamber 2 continuously or intermittently, and the concentration, the injection pressure, and the like of the urea aqueous solution are detected. Spraying while adjusting.

Next, each of the spray nozzles 13 and 14 will be described. Since the spray nozzles 13 and 14 have the same structure, only the spray nozzle 13 will be described here. As shown in FIG. 2, the spray nozzle 13 is of an internal mixing type, and has an inner pipe 20 for flowing the mixed solution and an outer pipe 21 surrounding the inner pipe 20 for flowing plant air. . Also, the internal mixing position 1 in the middle of the spray nozzle 13
At 3a, the mixed liquid and air are mixed. Further, an extension pipe portion 24 having an inner hole 24a is provided from the internal mixing position 13a of the spray nozzle 13 toward the free end side, and a tip portion 25 for injecting the mixture into the boiler 1 is provided at the tip thereof. Have been.

[0014] As also shown in FIGS. 3 and 4, extension pipe
The diameter of the portion 24 is the same from the proximal end to the distal end 25.
You. The distal end 25 has a hemispherical shape, is provided with a slit 25a as a spray port having a width smaller than the diameter of the inner hole 24a, and communicates with the inner hole 24a closed near the distal end 25. The slit 25a is opened at the tip of the extension tube portion 24 in a direction inclined by an angle θ with respect to the axial direction. Thereby, as shown in FIG. 5, the air-fuel mixture of the mixed liquid agent and the air is moved in a direction along the axial direction of the extension pipe portion 24,
That not beneath, such as spraying to lever toward the opposite exhaust side side, it is possible to increase the contact time for the exhaust of the urea, it can reduce the amount of leakage of ammonia it is possible to improve the denitration rate. Further, for example, the extension pipe portion 24
If there is a water pipe in the axial direction of the, it is conceivable that if the mixed solution comes into direct contact with the water pipe, cracks etc. will occur in the water pipe,
Its worried that <br/> Kunar by spraying in the direction without the water pipe.

Here, the extension pipe portion 24 is provided at the internal mixing position 13.
The downstream side of a, that is, mixing the mixed liquid and plant air
That guide the air-fuel mixture after combustion into the combustion chamber or exhaust passage
Therefore, there is no need to provide an inner tube and an outer tube,
The inner diameter of the single inner hole 24a is significantly smaller than that of the outer tube 21.
The outer diameter of the inner mixing position 13a
Significantly smaller than the end side, i.e. the tube can be made thinner.
Further, as described above, the extension tube portion 24 was expanded or bent.
By forming the slit 25a at an angle,
Injects air-fuel mixture obliquely to the axial direction of the long tube section 24
Therefore, even if the interval between the water pipes 3 adjacent to each other is small, the extension pipe section 24 can be easily inserted into the boiler 1, and the injection direction of the air-fuel mixture also rotates around the extension pipe section 24.
To rotate or adjust the position where the slit 25a is formed.
Can be set easily and freely .

It is needless to say that the present invention is not limited to the above embodiment, but can be applied in various ways. For example, in the above embodiment, the present invention is applied to a nitrogen oxide removing device of a heavy oil fired boiler. For example, various boilers, known thermoelectric supply devices (cogeneration), diesel engines, gas turbines, municipal solid waste incinerators, metal heating furnaces, petroleum heating furnaces, spraying equipment used for nitrogen oxide removal equipment in glass melting furnaces, etc. Applicable to

[0017]

As is apparent from the above description, according to the spray nozzle of the present invention, the liquid agent and the gas are internally mixed.
After mixing, the mixture is burned from outside with the extension pipe
By inserting it into the chamber or exhaust passage,
The extension tube can be made thin, and only the slit
The nozzle is tilted with respect to the axial direction of the
The tip of the nozzle, bend the nozzle,
Spray in the desired direction without installation
And especially for retrofitting to combustion equipment such as boiler equipment
When the nozzle is installed, the spraying direction can be set to a desired direction even when the installation location of the nozzle is limited, and it is difficult to install the nozzle at an angle, or when it is difficult to install a curved nozzle. The degree of freedom in setting is improved.

[Brief description of the drawings]

FIG. 1 is a partial side sectional view showing a configuration of a boiler device according to a preferred embodiment to which the present invention is applied.

FIG. 2 is an enlarged side view of a spray nozzle to which the present invention is applied.

FIG. 3 is an enlarged sectional view of a main part of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV in FIG. 3;

FIG. 5 is a view for explaining the operation of a spray nozzle in a preferred embodiment to which the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler 1a Wall 2 Combustion chamber 3 Heat exchange chamber 4 Partition wall 4a Upper through-hole 5 Burner 8 Storage tank 9 Pump 10 Mixing unit 11 Controller 12 Plant water supply pipe 13, 14 Spray nozzle 13a Internal mixing position 15 Plant air supply pipe 20 Tube 21 outer tube 24 extension tube 24a inner hole 25 tip 25a slit

Continuing on the front page (72) Inventor Shin Ito Shinnobu Residence, 3rd Floor, Kitanomaru Residence, 2-3-9 Kudankita, Chiyoda-ku, Tokyo Inside Blue Knox Japan Co., Ltd. (72) Inventor Takayuki Sato 2-2 Azuma, Narita-shi, Chiba JP-A-4-16216 (JP, A) JP-A-1-502495 (JP, A) JP-T-2-503764 (JP, A)

Claims (1)

(57) [Claims] 1. A so as to remove nitrogen oxides generated in the exhaust of a combustion device (NOx), used in an injector for spraying the urea solution into the combustion chamber or an exhaust passage of said combustion apparatus, the urea aqueous solution and the gas inside Mix and spray
A spray nozzle of fit, the combustion from the position for mixing the external of the urea aqueous solution and a gas
An extension pipe portion having a length reaching the inside of the chamber or the exhaust passage, and a slit-shaped spray port opened at the tip of the extension pipe portion.
And the extension pipe portion has its entirety from its proximal end to its distal end.
The same diameter over the length, and the slit-shaped spray port,
A spray nozzle characterized in that the opening is inclined with respect to the axial direction of the extension pipe .