KR100625566B1 - External-mix type nozzle assembly for selective catalytic reduction system - Google Patents

Abstract

The externally mixed injection nozzle assembly according to the present invention has an outer nozzle having a plurality of injection holes formed in the bottom surface injection part of the lower surface of the lower surface and a closed portion, and is disposed to be spaced apart to have a predetermined gap in the external nozzle. The outer periphery is formed on the outer periphery so that the outer periphery is formed, and the bottom fixing part of the lower part is closed, the inner nozzle holder is formed with a plurality of fixing holes, and one end is fixed to the fixing hole of the bottom fixing part of the inner nozzle holder. Consists of a plurality of inner nozzle body formed with a spiral turning portion on the surface, it is sprayed by a plurality of inner nozzle body per one injection nozzle assembly, it is possible to be evenly sprayed in all the reaction space and the turning formed inside each inner nozzle body As the urea solution increases its momentum as it passes through the section, As it becomes faster, the size of the spray droplets becomes smaller, so that the evaporation takes less time even at a lower temperature, and if necessary, a large number of internal nozzle bodies can be expanded by only a slight structural change without requiring additional equipment. It is possible to increase the amount of use more effectively, and the spray angle is almost constant even with the change of the flow rate or the pressure, which makes it easy to design the equipment according to the change. Also, more nozzles are connected according to the design of the nozzle. It is possible to achieve this, and accordingly, the invention has an excellent effect of facilitating adjustment of the spray amount as desired.

Description

Large-capacity urea solution for low temperature selective catalytic reduction system Externally mixed type nozzle assembly for selective catalytic reduction system

1 is a fragmentary longitudinal cross-sectional perspective view from below of an externally mixed injection nozzle assembly in accordance with one embodiment of the present invention;

Figure 2 is a cut away longitudinal section perspective view from the front of the externally mixed injection nozzle assembly according to an embodiment of the present invention;

3 is a schematic plan view of an externally mixed spray nozzle assembly according to one embodiment of the present invention;

4A is a perspective view of a solution jet internal nozzle body of the jet nozzle assembly of the present invention;

Fig. 4B is a front view of the solution jet internal nozzle body of the jet nozzle assembly of the present invention.

5 is a schematic longitudinal cross-sectional view of a conventional externally mixed spray nozzle assembly.

Explanation of symbols on the main parts of the drawings

10. External nozzle 11. Screw surface 12. Bottom injection part

13. Injection hole 20. Inner nozzle holder 21. Outer extension part

22. Air distributors 23. Bottom fixing government 24. Fixtures

30. Inner jizz body 31. Swivel

The present invention relates to an external-mix type nozzle assembly for selective catalytic reduction system for a large-capacity urea solution for low temperature selective catalytic reduction system for injecting an aqueous urea solution for reducing nitrogen oxides. In addition, it is possible to efficiently inject a large amount of urea aqueous solution into the exhaust gas even with one injection nozzle assembly, which improves the spraying ability and makes the manufacturing cost cheap, and also activates the reactor at a low temperature by atomizing the reactive agent. The well-formed externally mixed spray nozzle assembly is provided to reduce the waste of energy by eliminating the additional heat source previously required to maintain the activation temperature.

At present, Korea's living standard is improving and its lifestyle is changing with rapid economic development. In addition to improving living standards, the amount of wastes generated from homes and industries is increasing rapidly, and the characteristics of wastes are diverse and complicated, and the disposal of wastes is an important task.

Due to the cumulative increase in landfills accumulated annually, existing landfills are now saturated, and the government is prioritizing waste disposal by incineration rather than landfill-based waste disposal.

Accordingly, as the demand for incinerators increases in Korea, there is a growing interest in the safe treatment of various exhaust gases generated in incinerators.

Nitrogen oxides among the harmful exhaust gases generated during incineration of wastes are mainly composed of thermal NOx generated by heat sources during incineration.

As a method for removing such NOx, selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) are mainly used. In the case of SNCR, the NOx removal efficiency is lowered at the expense of lower initial investment and operating costs, while in SCR, the initial investment is higher, while the NOx removal efficiency is significantly higher than that of SNCR.

As a reducing agent for removing such NOx, ammonia (NH₃) has been mainly used. However, in the case of ammonia, it is difficult to store, difficult to transport, toxic and bad odors, so the actual application has many problems.

Because of these problems, urea aqueous solution, which is more stable than ammonia and has no smell, is used as a reducing agent for NOx removal. However, in the case of urea aqueous solution, thermal decomposition was well performed in the existing high temperature region, and thus it was smoothly used to remove NOx. However, in the low temperature region (180 to 250 ° C.), pyrolysis was not performed well.

In addition, in the case of SCR, the injection nozzle is used to increase the kinetic energy of the reducing agent to move the reducing agent so that the reduction reaction is performed well on the catalyst.

In order to inject the reducing agent, an external mixed type two-fluid injection nozzle which injects a reducing agent while air is injected from the outside is widely used, and in the case of this nozzle, a method of injecting a reducing agent from one injection hole is used. come.

As shown in FIG. 5, the conventional externally mixed type injection nozzle 100 is composed of one external nozzle 101 and one internal nozzle 102 inserted into the external nozzle 101, and thus, one external injection type injection nozzle. Since the injection capacity of the reducing agent injected into the nozzle is small, the installation of a plurality of external injection nozzles is required, resulting in a high equipment cost.

 Accordingly, research on nozzles that enable the atomization of reducing agents to enable thermal decomposition even when reducing agents are used as urea solutions in low temperature areas, and the increase in equipment costs generated by using multiple nozzles where large amounts of reducing agents are required. Development of a large-capacity nozzle to replace the has continued.

An object of the present invention is to efficiently spray a large amount of reducing agent (urea aqueous solution) into the exhaust gas even with one injection nozzle assembly in the apparatus for reducing nitrogen oxides in the exhaust gas generated in power plants, incinerators, chemical plants, and glass melting furnaces. It is possible to provide an externally mixed type high-capacity injection nozzle assembly that can be made to improve the injection capacity and the manufacturing cost is low.

In addition, by minimizing the size of the droplets of the sprayed reducing agent to activate well in the low temperature region (180 ~ 250 ℃) of the additional heat source device previously required to maintain the activation temperature (280 ~ 350 ℃) in the low temperature region By eliminating the necessity, the installation cost is remarkably inexpensive and the waste of energy is reduced to provide an externally mixed type high-capacity spray nozzle assembly that is resource-saving.

The object of the present invention is that the outer surface is formed in the bottom surface injection portion of the lower surface and the screw surface is formed on the inside and the outer nozzle and a plurality of injection holes are formed to be spaced apart to have a predetermined gap in the outer nozzle is formed on the outer periphery A plurality of air flow holes are formed and the lower bottom fixing part of the lower portion is formed, the inner nozzle holder is formed with a plurality of fixing holes, the one end is fixed to the fixing hole of the bottom fixing part of the inner nozzle holder, the plurality of spiral turning portion formed on the inner surface It is achieved by an externally mixed injection nozzle assembly according to the present invention consisting of an inner nozzle body of a.

The externally-mixed spray nozzle assembly according to the present invention will be more clearly understood on its features and advantages by the embodiments described in detail below with reference to the accompanying drawings.

Injection nozzle assembly (A) according to an embodiment of the present invention, as shown in Figure 1 to Figure 3, as a whole having different inlet and outlet lines so that air and urea aqueous solution can be injected without affecting each other It consists of three parts. The injection nozzle assembly (A) has an external nozzle (10) having a plurality of injection holes (13) formed on the bottom surface injection part (12) and a lower bottom injection part (12) closed inside, and the external nozzle (10). The outer bottom portion 21 having a plurality of air distribution holes 22 is formed on the outer circumference so that the air circulation gap G is formed to be spaced apart to have a predetermined gap) and the bottom fixing part 23 of the lower portion is closed. One end is fixed to the inner nozzle holder 20 having a plurality of fixing holes 24 and the fixing hole 24 of the bottom fixing part 23 of the inner nozzle holder 20, and spirally swinging on the inner surface. It consists of the some internal nozzle body 30 in which the part 31 was formed.

The outer nozzle 10 has a function of injecting air while allowing air to pass through the gap G with the inner nozzle holder 20, and a plurality of powders are disposed in the lower bottom injection part 12 at the lower portion so that the air is injected. The hole 13 is formed. In the present embodiment, three injection holes are formed at intervals of 120 degrees, but the number of injection holes may be further increased in order to inject a large capacity. The injection hole 13 is formed to be inclined to be sprayed in a wide direction, and should have an appropriate size to facilitate mixing with the urea aqueous solution, the diameter of the injection hole 13 is the injection end of the inner nozzle body (30) The size of about 1.5 to 1.7 times the outer diameter of (32) is preferable. An orifice gap O through which air passes is formed between the injection hole 13 and the inner nozzle body 30.

The inner nozzle holder 20 has an inlet 25 through which the urea aqueous solution flows in the center, a screw surface 26 is formed on the outer surface thereof, and an outer extension portion in which a plurality of air flow holes 22 are formed ( 21 is formed and a plurality of fixing holes 24 are formed in the bottom fixing part 23 in the lower portion. A screw surface is formed on the fixing hole 24 so that the inner nozzle body 30 is detachably assembled. The fixing hole 24 is formed to be inclined at a predetermined angle, the inner nozzle body 30 is installed to be inclined.

As shown in FIGS. 4A and 4B, the inner nozzle body 30 includes a fixed end portion 33 and a threaded end portion formed with a screw surface coupled to a screw surface of the fixing hole 24 of the inner nozzle holder 20. The injection end part 32 which sprays aqueous solution is formed in both ends, and the spiral turning part 31 for raising the momentum of urea aqueous solution is formed in the inside surface 34 through which urea aqueous solution passes.

Effects of the externally mixed injection nozzle assembly A according to the present invention having such a configuration will be described in detail below.

When the urea aqueous solution is to be injected, when the external air and the urea aqueous solution are respectively introduced into the air inlet gap G of the injection nozzle assembly A and the inlet 25 of the inner nozzle holder 20, the air inlet gap G Air flows into the orifice (O) formed between the injection hole 13 and the inner nozzle body 30 while passing through the air distribution hole 22 and hit the bottom surface injection portion 12 of the bottom of the outer nozzle 10 Sprayed through, the urea solution introduced into the inlet 25 of the inner nozzle holder 20 is moved to the bottom fixing part 23, the three inner nozzle body 30 fixed on the fixing hole 24 Sprayed in the direction. The injection speed of the air introduced into the air inlet gap G and injected from the external nozzle is about 3 kgf / cm 2, and the injection speed of the aqueous solution injected from the inner nozzle body 30 is about 2 to 2.5 kgf / cm 2. to be. The aqueous urea solution introduced into the three inner nozzle bodies 30 disposed at 120 degrees is sprayed while rotating in a spiral direction as the shape of the turning part 31 while contacting the turning part 31 while flowing along the inner side 34. It is discharged through the end 32 and such an aqueous urea solution is to be injected as sucked out by the air injected at a higher pressure through the orifice (O). Therefore, the urea aqueous solution introduced into the inner nozzle holder 20 is sprayed by the inner nozzle body 30 disposed to be inclined at 120 degrees, so that the urea aqueous solution can be evenly sprayed in all the reaction spaces, which makes it possible to spray the inner nozzle evenly. As the urea aqueous solution increases its momentum while passing through the turning part 31 formed inside the sieve 30, the spraying speed of the aqueous solution is increased, so that the size of the spray droplets is reduced, so that the evaporation time takes less time at low temperatures. In the present embodiment, three inner nozzle bodies are fixed on one spray nozzle assembly, but if necessary, more inner nozzle bodies are installed without requiring additional equipment, thereby making it possible to increase the spraying capacity more effectively. . In addition, the spray angle is almost constant even with the change of the flow rate or the pressure, so the design of the equipment is easy, and more nozzles can be connected according to the design of the nozzle. It is also easy to adjust.

As described above, the externally mixed injection nozzle assembly according to the present invention has an external nozzle having a plurality of injection holes formed in the lower surface injection part of the lower part of which the screw surface is formed on the inner side, and is spaced apart from each other to have a predetermined gap in the air. The outer periphery is formed on the outer circumference so as to form a clearance gap, and the bottom fixing part of the lower part is formed in the closed bottom fixing part, and one end is fixed to the fixing hole of the fixing part of the bottom fixing part of the inner nozzle holder. It is fixed and consists of a plurality of inner nozzle bodies having spiral turns on the inner surface, and is sprayed by a plurality of inner nozzle bodies per one spray nozzle assembly, so that it is possible to spray in all reaction spaces evenly. As the aqueous solution of urea increases as it passes through the turning part formed inside, As the spraying speed increases, the size of the spray droplets becomes smaller, so it takes less time to evaporate even at low temperatures, and if necessary, it is necessary to add a large number of internal nozzle bodies with only a slight structural change without requiring additional equipment. It is possible to increase the injection capacity more effectively, and also has the advantage that the design of the equipment according to the change of the flow rate and the pressure change is almost constant, so that the design of the equipment is easy, and also according to the design of the nozzle Many nozzles can be connected, according to the invention has an excellent effect that is easy to adjust the amount of spray as desired.

Claims (4)

In an externally mixed spray nozzle assembly, The injection nozzle assembly may include an outer nozzle having a plurality of injection holes formed in the bottom injection part of the closed lower part, and an inner nozzle holder formed with a plurality of fixing holes in the closed bottom fixing part of the lower part and having a predetermined gap therebetween. And a plurality of inner nozzle bodies having one end fixed to the fixing hole of the bottom fixing part of the inner nozzle holder and spraying an aqueous solution, and an orifice is formed between the spray hole of the outer nozzle and the spraying end of the inner nozzle body. Mixed spray nozzle assembly According to claim 1, wherein the inner nozzle body is a fixed end portion formed with a screw surface coupled to the screw surface of the fixing hole of the inner nozzle holder and the injection end portion is injected into the urea aqueous solution is formed at both ends and the urea aqueous solution is inside Externally mixed injection nozzle assembly, characterized in that the spiral turning portion for increasing the momentum of the aqueous urea solution is formed on the inner surface passing through According to claim 1, Externally mixed on the outer surface of the inner nozzle holder is formed with a plurality of air flow holes formed on the outer periphery so as to be spaced apart to have a predetermined gap in the outer nozzle is formed in the outer periphery Spray nozzle assembly The externally mixed spray nozzle assembly of claim 1, wherein the inner nozzle body is disposed to be inclined.

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