JPH11333332A - Spray nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need for preparing a slaked lime slurry by preventing the closure of a spray device, etc., by the slaked lime slurry and facilitating the maintenance. SOLUTION: This spray nozzle consists of a combination of an inner nozzle 2 which consists of double piping composed of a central flow passage 21 and an outer flow passage 22 formed on its outer periphery, feeds water of a suitable pressure into the outer flow passage 22 from a feed port 23 and sprays the water in the front end 24 of the outer flow passage 22 and an outer nozzle 3 which swirls and ejects slaked lime powder by pressurized air to the circumference of this inner nozzle 2. The front end portion thereof is mounted to face the inside of an exhaust gas duct 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for neutralizing and removing hydrogen chloride, sulfur oxide and the like contained in exhaust gas generated from incinerators such as municipal waste, industrial waste and sewage sludge. The present invention relates to a spray nozzle for an alkali neutralizer used in an exhaust gas treatment device.

[0002]

2. Description of the Related Art Conventionally, an exhaust gas treatment apparatus using an alkali neutralizing agent such as slaked lime to treat hydrogen chloride and the like in the exhaust gas has been shown in FIG. And a semi-dry apparatus using a water slurry of an alkali neutralizer shown in FIG.

[0003] In the all-dry flow shown in FIG. 4, after the exhaust gas generated from the incinerator 11 is heat-exchanged by the heat exchanger 12, dust is removed by the cyclone 13, and then the dry EP 15
Is processed so as to remove fine dust and release from the chimney 16.

[0004] In this case, by blowing slaked lime powder from the slaked lime powder tank 14 into the duct immediately before the dry EP 15, the acid gas components such as hydrogen chloride and sulfur oxide in the exhaust gas are neutralized, and the reaction product is formed. The matter is separated and removed together with fine dust in the dry EP15. This all-dry neutralization and removal apparatus requires a small facility cost, but has a problem that the removal efficiency is low because the reactivity with the acidic gas is not so large.

In the semi-dry flow shown in FIG. 5, the exhaust gas passing through the cyclone 13 is guided to the reaction tower 17, while a mixed slurry of slaked lime and water prepared in advance in the mixing tank 14a is sprayed into the tower, and the exhaust gas is discharged. To cause a neutralization reaction with the acidic gas component contained in. Then, the sediment of the reaction product is taken out from the bottom, and the floating product is further removed by the bag filter 1.
At 8, it is separated and removed together with other dust in the exhaust gas.

Although this semi-dry neutralization and removal apparatus has the advantage of high reactivity with acidic gas components and high removal efficiency, slaked lime in the slurry can be converted into insoluble solids such as calcium carbonate. There is a problem that these materials are liable to be deteriorated and settle and accumulate in the slurry piping, the piping in the spraying device, and the inside of the nozzle to be clogged, and the maintenance for preventing such trouble is troublesome.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the neutralizing and removing apparatus, and can prevent blockage of a spraying apparatus or the like by an alkali neutralizing agent such as slaked lime slurry. Provided is a spray nozzle having a structure that is easy to maintain, and further eliminates the need for a mixing facility for manufacturing slaked lime slurry and a pipe for supplying the slurry.

[0008]

SUMMARY OF THE INVENTION A spray nozzle according to the present invention, which has been made to solve the above problems, includes an inner nozzle for spraying water at a tip portion, and a slaked lime powder formed around the inner nozzle. It is characterized by comprising means for forming a jet flow, and having a combination structure of an outer nozzle for jetting by mixing the spray water and the slaked lime powder.

Further, the present invention provides an inner nozzle for spraying water at a distal end thereof, and a slaked lime powder formed around the inner nozzle and fed together with compressed air from an inlet provided at a proximal end thereof. An outer nozzle that forms the jet flow and mixes and sprays the sprayed water and the slaked lime powder.At the inlet, the axis of the slaked lime supply pipe is offset from the axis of the outer nozzle. Thus, a spray nozzle characterized in that the jet flow of the slaked lime powder is formed in a swirling state.

[0010] Further, the spray nozzle of the present invention is embodied in a form in which a heating duct for covering the outer periphery of at least a portion of the outer nozzle corresponding to a mixing region of spray water and slaked lime powder is provided. Can be.

[0011]

Next, an embodiment of a spray nozzle according to the present invention will be described with reference to FIGS. In FIG. 1, the spray nozzle of the present invention is composed of a combination of an inner nozzle 2 for spraying water and an outer nozzle 3 for ejecting slaked lime powder as an alkali neutralizer, and a tip 24 of the inner nozzle 2 It is assembled facing the inside of the outer nozzle 3.

The inner nozzle 2 forms a central flow path 21 and an outer flow path 22 located on the outer periphery thereof.
It is composed of heavy pipes, and water at an appropriate pressure is fed into the outer flow path 22 from the water supply port 23, becomes spray water at the tip end portion 24 of the outer flow path 22, and is sprayed into the duct 4 through which the exhaust gas flows. Is returned from the outlet 25 as return water through the central flow path 21. Such an inner nozzle 2 is a nozzle called a one-fluid spray nozzle or an airless nozzle, and is capable of adjusting and changing the spray water pressure and the spray pattern by controlling the return water amount.

A feature of the present invention is that an alkaline neutralizing agent such as slaked lime powder dried by pressurized air is provided around a portion including at least the tip portion 24 of the inner nozzle 2 for spraying such water. In that the outer nozzle 3 provided with a means for forming a jet flow containing

The outer nozzle 3 is, as shown in FIG. 1, composed of a cylindrical casing which is assembled so as to surround the distal end 24 of the inner nozzle 2. An inlet 32 for feeding the neutralizing agent together with the air is provided, and a front end portion is arranged facing the exhaust gas duct 4.

The space between the tip 24 of the inner nozzle 2 and the exhaust gas duct 4 in the outer nozzle 3 is made of slaked lime powder which is fed together with the compressed air from the inlet 32. Forming a jet flow, preferably forming a swirling jet flow as shown in FIG. 1, and forming a mixing channel 31 for mixing the spray water and the slaked lime powder to jet into the exhaust gas duct 4. doing.

The reason why the jetted flow of the slaked lime powder is formed in a swirling state is, for example, that the axis of the slaked lime supply pipe (not shown) is connected to the feed port 32 of the outer nozzle 3. This can be realized by arranging it offset from the axis. That is, if slaked lime powder is fed by compressed air from the slaked lime supply pipe whose axis is deviated, the airflow containing the slaked lime becomes a jet flow swirling along the inner surface of the cylindrical casing of the outer nozzle 3.

In such a spray nozzle having the outer nozzle 3, the slaked lime powder is swirled and fed by the compressed air from the inlet 32 of the outer nozzle 3, so that the inner nozzle 2 is generated in the mixing channel 31. The sprayed water and the slaked lime powder collide violently, and the water droplets and the slaked lime powder can be integrated into a slurry. The spray water droplets containing the slaked lime are discharged from the exhaust gas duct 4
It diffuses widely inside and the reaction with the acid gas is efficiently performed.

In the case of such a spray nozzle of the present invention, the jetting speed of the alkali neutralizing agent particles by the outer nozzle 3 with respect to the spray water droplets generated by the inner nozzle 2 is made as large as possible. It is preferable to make a collision while making a turning motion.

The size of the spray water droplet is usually 80-100 μm.
On the other hand, the powder particle size of the generally available slaked lime powder, which is generally available, is under 50 μm, so that the collision speed of the small-sized slaked lime powder is set to be large, and It was recognized that the probability of collision of both particles was increased by swirling. Controlling the velocities of both particles in this way is particularly preferred in order to obtain a spray slurry homogeneously containing slaked lime.

Further, in the spray nozzle of the present invention, the outer nozzle 3 is externally heated so that spray water droplets adhere to the inner surface of the nozzle and slaked lime can be prevented from adhering and accumulating. Can be.
One example is shown in FIG. 2, in which a heating duct 5 covering the outer periphery of the outer nozzle 3 is provided at least in a portion corresponding to a mixing channel 31 which is a mixing region of spray water and slaked lime powder. The heating duct 5 has an inlet 51
The outer nozzle 3 is heated by supplying high-temperature heat recovery air from the nozzle, thereby rapidly heating and evaporating the spray water droplets adhered to the inside of the outer nozzle. This prevents sticking and deposition.

As the above-mentioned heat recovery air, high-temperature air (about 300 ° C.) effectively recovered in the incinerator is used. The surface temperature of the outer nozzle 3 heated by this high-temperature air is about 150 ° C. To rise. And since the high temperature air is continuously supplied, the temperature of the outer nozzle keeps the above temperature, so that the spray water droplets adhering to the inner surface of the nozzle are instantaneously heated and evaporated, and the slaked lime is also applied to the inner surface of the nozzle. It is sent to the exhaust gas duct 4 without being deposited.

In the example shown in FIG. 2, the shape of the outer nozzle 3 is set so that the inner diameter is reduced and narrowed from the central portion to the distal end portion. In this case, the turning of the slaked lime and the flow velocity of the jet flow are accelerated, so that a more preferable mixing state is obtained. However, the present invention is not limited to this shape, and may have a straight shape.

Next, in the all-dry neutralization removing apparatus shown in FIG. 4, the case where slaked lime powder is blown from the slaked lime powder tank 14 into the duct immediately before the dry EP 15, A comparison was made between the case where spray water containing slaked lime was blown by the spray nozzle of the above embodiment. In this case, the exhaust gas flow rate: 6000N
m ³ / h, gas temperature: 300 ° C., gas velocity: 20 m /
s, acid gas concentration at cyclone outlet, SOx: 90p
pm, HCl: 450 ppm.

Under these conditions, the neutralization and removal operations were performed, and the concentration of the residual acid gas was measured at the outlet of the dry EP.
x: 63 ppm (30% removal rate), HCl: 225 pp
m (removal rate 50%), whereas in the case of the spray nozzle of this embodiment, SOx: 45 ppm (removal rate 50%)
%) And HCl: 90 ppm (removal rate 80%). As described above, it has been found that the spray nozzle of the present invention can be effectively applied to a completely dry neutralization removing device.

In this comparative test, in the case of the nozzle of the present invention, solid matter generated from slaked lime was not observed on the nozzle body as well as on the related piping, and no clogging phenomenon occurred. In this description, an example is shown in which the spray nozzle of the present invention is applied to the all-dry neutralization / removal device of FIG. 4, but the neutralization reaction tower 17 of the semi-dry neutralization / removal device shown in FIG. It is preferably applicable.

As another embodiment of the inner nozzle 2 constituting the spray nozzle of the present invention, the structure shown in FIGS. 3A and 3B is exemplified. In the case of FIG. 3A, the spraying water is supplied from the opposite direction as compared with the case of the inner nozzle of FIG. Type
(B) is a type in which the water for spraying is supplied to the central flow path 21 and the air for spraying is supplied through the outer flow path 22 to perform the spraying action at the tip end. It is applicable to the invention.

[0027]

Since the spray nozzle of the present invention is configured as described above, the slurry does not stay in the slaked lime in the related piping and the nozzle body. Objects do not settle and accumulate on piping, spraying equipment and nozzles, and of course no clogging occurs. Therefore, there is an effect that the maintenance is not required.

Further, there is no need for a mixing facility for preparing slaked lime slurry in advance, and there is an excellent effect that it can be applied not only to a semi-dry type but also to a full-dry type neutralization removing device. Therefore, the present invention has a very large industrial value as a spray nozzle which has solved the conventional problems.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view for explaining a use state of a spray nozzle of the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the present invention.

FIG. 3 is a schematic sectional view showing another example of the inner nozzle applicable to the present invention.

FIG. 4 is a flowchart showing a main part of the all-dry neutralization removing device.

FIG. 5 is a flowchart showing a main part of the semi-dry neutralization removing device.

[Explanation of symbols]

2 inner nozzle, 21 center flow path, 22 outer flow path, 23 inlet, 24 tip, 3 outer nozzle,
31 mixing channel, 32 inlet, 4 duct, 5 heating duct, 51 inlet.

Claims (3)

[Claims] 1. An inner nozzle for spraying water at a tip end thereof, and means for forming a jet flow containing slaked lime powder formed around the inner nozzle, and mixing the sprayed water with the slaked lime powder. A spray nozzle having a combined structure with an outer nozzle that jets out. 2. An inner nozzle for spraying water at a distal end thereof, and a jet flow of slaked lime powder formed around the inner nozzle and fed together with compressed air from an inlet provided at a proximal end thereof. And an outer nozzle that mixes and sprays the sprayed water and the slaked lime powder.At the inlet, the axis of the slaked lime supply pipe is arranged offset from the axis of the outer nozzle. A spray nozzle characterized by forming a jet of slaked lime powder in a swirling state. 3. The spray nozzle according to claim 1, further comprising a heating duct that covers an outer periphery of at least a portion of the outer nozzle corresponding to a mixing region of spray water and slaked lime powder.