JPH04118133U - Exhaust gas reducing agent spray device - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the spray nozzle from being blocked by precipitated urea in a spray device that sprays urea water for denitrification into the exhaust pipe. [Structure] A sprayer 11 provided inside an exhaust pipe has a supply pipe 15 to which urea water is supplied and a spray nozzle 17 at the tip. Since the supply pipe 15 is covered with a heat insulating material 20, even if exposed to high temperature exhaust gas, there will be no problem that urea will precipitate and block the spray nozzle.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is an exhaust gas reducing agent spray device used for exhaust gas purification using a reduction catalyst. It's about location.

0002

[Conventional technology]

Reduction of NOx in exhaust gas from diesel engines and the like has become an urgently important issue. At present, the reduction of NOx generation by improving the engine side has reached its limit. Therefore, it becomes necessary to purify exhaust gas, that is, denitrification (reduction of NOx) using a reduction catalyst. It's coming. Reducing agents used in such reduction reactions include ammonia gas and ammonia gas. There is water and urea water. However, ammonia gas and ammonia water are dangerous substances. Due to restrictions on handling due to occupational safety and health concerns, small and medium-sized cogeneration tion system is difficult to use for denitrification. Therefore, in a facility of this size, the At present, it has been difficult for denitrification equipment for diesel exhaust gas to become widespread.

0003

[Problem that the idea aims to solve]

Since urea water is not dangerous and easy to handle, urea water is used as a reducing agent for denitrification. There is a strong desire to establish technology that However, a spray nozzle is installed in the exhaust pipe through which high-temperature exhaust gas flows, and urea water is sprayed. When you try to spray, the water evaporates due to the high temperature, and urea precipitates out, blocking the pores of the nozzle. There was a problem with it getting clogged. Especially when the exhaust gas temperature is high and the operation is performed at a low denitrification rate. In this case, since the amount of urea water is small, the cooling effect of urea water itself is small, and the above problem is solved. The issue is particularly salient.

0004 This invention uses a spray nozzle in a spray device that injects urea water inside an exhaust pipe. The purpose is to prevent blockages.

[0005]

[Means to solve the problem]

The spray device of this invention uses urea that protrudes inside the exhaust pipe that leads the exhaust gas to the denitrification reactor. A water supply pipe, a spray nozzle provided at the tip of the supply pipe, and covering the supply pipe. It is equipped with a heat insulating part.

[0006] In addition, instead of the heat insulation section, a forced cooling section that circulates the coolant to cool the urea water. may be provided.

[0007] In addition, the urea water spray nozzle inside the exhaust pipe that leads the exhaust gas to the denitrification reactor is selectively The structure is designed to supply water to the

[0008]

[Effect]

According to the device of claim 1 or 2, at least the supply pipe exposed to the exhaust gas The temperature of the urea water decreases because the parts are insulated from high temperatures or forced to cool. This prevents the precipitation of urea in the spray nozzle. Further, according to the device of claim 3, To prevent the spray nozzle from becoming clogged with precipitated urea, spray water instead of urea water. Can expel urea water.

[0009]

【Example】

As shown in Fig. 1, the exhaust pipe 2 of the diesel engine 1 has a denitrification reactor equipped with a catalyst. reactor 3 is connected. A NOx concentration measuring device 4 is installed at the outlet of the denitrification reactor 3. I'm being kicked.

0010 The exhaust pipe 2 is provided with a spray device 5 of urea water which is an exhaust gas reducing agent. Then, urea water is sprayed into the exhaust pipe 2.

[0011] The spray device 5 is connected to a urea water supply unit 6. This supply unit The kit 6 includes a water purifier 7 for producing pure water from tap water, a flow control valve 8 and a pump 9. It has a urea water supply tank 10 equipped with a urea water supply tank 10, and supplies pure water and urea water to the spray device 5. can be supplied.

0012 As shown in FIG. 2, the spray device 5 includes two sprayers 1 protruding into the exhaust pipe 2. 1, 11, and a switching unit 12 that supplies urea water or pure water to these sprayers 11. It has

[0013] As shown in FIG. 2, the atomizer 11 is attached to an exhaust pipe 2 by means of a mounting flange It is attached to the attachment port 14 of. As shown in Figure 3, this mounting flange 1 3 is provided with a supply pipe 15 passing through it, and the distal end side of the supply pipe 15 is connected to the length of the exhaust pipe 2. It protrudes into the interior of the exhaust pipe 2 in a direction perpendicular to the hand direction. And this supply pipe 1 A spray nozzle 17 is attached to the tip of the spray nozzle 5 via a holder 16. The nozzle hole 18 of the nozzle 17 is oriented in the longitudinal direction of the exhaust pipe 2.

[0014] The supply pipe 15 protruding into the exhaust pipe 2 is covered by an outer cylinder 19. A heat insulating material 20 is filled between the supply pipe 15 and the supply pipe 15 as a heat insulating part. And before The holder 16 and the spray nozzle 17 are connected to each other through holes provided in the side peripheral wall of the outer cylinder 19. It protrudes outside the outer cylinder 19.

[0015] As shown in FIG. 2, the switching unit 12 has two three-way valves 21, 21. ing. The urea water piping 22 led from the supply unit 6 passes through a filter to the urea water pipe 22. The three-way valves 21, 21 are each connected to one inlet thereof. The pure water pipe 23 led from the supply unit 6 passes through a filter and branches into two. , are connected to the other ports of the three-way valves 21, 21, respectively. And three sides The respective outlets of the valves 21, 21 are connected to the supply pipes 15, 15 of the respective atomizers 11, 11, respectively. connected.

[0016] In the above configuration, when the diesel engine 1 is operating, as shown in FIG. The supply unit 6 supplies urea water to the spray device 5. Switching unit of spray device 5 In the kit 12, each three-way valve 21, 21 is switched to the urea water supply side, and each sprayer 11 is switched to the urea water supply side. Urea water is sprayed from the spray nozzle 17 into the exhaust pipe 2, which causes the denitrification reactor to In No. 3, NOx is efficiently reduced.

[0017] The sprayer 11 in the exhaust pipe 2 is exposed to high temperature exhaust gas, but the supply pipe through which urea water passes 15 is insulated with a heat insulating material 20, so urea is precipitated from the urea water and the spray nozzle The nozzle holes 18 of 17 will not be blocked. Therefore, the spray of urea water is stable, Therefore, the denitrification performance of the denitrification reactor 3 is also stabilized.

[0018] If urea water remains in the sprayer 11 when spraying is stopped, the urea water will It is dried by the surrounding heat, and urea precipitates and blocks the nozzle hole 18. So In this embodiment, three of the switching units 12 are operated before the start of spraying and after the end of spraying. Switch the direction valves 21, 21 to the pure water side and replace the residual urea water in the sprayer 11 with pure water. I have extracted it and replaced it. As a result, the spray nozzle 17 is already closed when denitrification starts. The inconvenience of not being able to spray due to a blockage can definitely be avoided.

[0019] In this embodiment, two sprayers 11 are provided. The nozzle hole has a large cross-sectional area. Rather than installing one sprayer, it is better to use two sprayers even if the total amount of spray is the same. If installed, finer spray particles can be obtained and the denitrification performance can be improved. There is an advantage. In addition, the load on diesel engine 1 is small, and the amount of urea water supplied is If a small amount is acceptable, close the three-way valve 21 on one side of the switching unit 12 and Only the sprayer 11 may be used.

[0020] FIG. 4 shows another structural example of the sprayer in the above embodiment. This sprayer 3 0, the supply pipe 31 to which urea water or water is supplied is located at the center of the cylindrical outer cylinder 32. It is set in. The base end 31a of this supply pipe 31 is connected from one end surface of the outer cylinder 32. It is attached to the outer cylinder in a state of protruding outward, and can be connected to the switching unit 12 side. It is now possible to In addition, a spray nozzle is connected to the tip of the supply pipe 31 via a holder 33. The holder 33 and the spray nozzle 34 are attached to the tip of the outer cylinder 32. It is attached to the outer cylinder 32 in a state of protruding from the side peripheral wall of the outer cylinder 32. Also A pair of partition plates 36 are provided between the inner peripheral surface of the outer cylinder 32 and the outer peripheral surface of the supply pipe 31. It is being This partition plate 36 extends along the longitudinal direction of the supply pipe 31 into one part of the outer cylinder 32. It extends from the inner surface of one end face to the vicinity of the holder 33. by this, The space between the outer cylinder 32 and the supply pipe 31 is divided into two cooling chambers that communicate with each other. This is a forced cooling section 40 to which cooling fluid is circulated and supplied. Then, the outer cylinder 32 is provided with a mounting flange 35 that is fixed to the mounting port 14 of the exhaust pipe 2. Furthermore, when installed, the base end of the outer cylinder 32 located outside the exhaust pipe 2 is connected to the inside of the outer cylinder 32. There is an inlet 37 and an outlet 38 for the passage of cooling fluid.

[0021] When the sprayer 30 is attached to the exhaust pipe 2 and used for supplying urea during denitration, the sprayer 30 is installed outside the exhaust pipe 2. Cooling fluid is supplied from the inlet 37 of the cylinder 32, and cooling fluid is discharged from the outlet 38. The urea water supplied into the supply pipe 31 is forcibly cooled.

[0022] When the exhaust gas temperature is high and the engine is operated at a low denitrification rate, the flow rate of urea water is low. The cooling effect of urea water itself is small. In such a case, the sprayer 30 of this embodiment By using urea water, it is possible to forcibly cool down the urea water, so no leakage caused by urea precipitation can be avoided. Blockage of the drain hole can be reliably prevented.

[0023]

[Effect of the idea]

According to the exhaust gas reducing agent spraying device according to the present invention, the supply pipe through which urea water passes is insulated or Since it is cooled, there is no precipitation of urea due to the heat of the exhaust gas, and the spray nozzle is It never gets blocked. In addition, by supplying water instead of urea water, spraying Since residual urea water in the container can be replaced, nozzle clogging due to urea precipitation can be prevented. Ru.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a spray device in the same embodiment.

FIG. 3 is a sectional view of the sprayer in the same embodiment.

FIG. 4(a) is a sectional view showing another configuration example of the sprayer in the same embodiment, and FIG. 4(b) is a sectional view taken along the line bb in FIG. 4(a).

[Explanation of symbols]

2 Exhaust pipe 3 Denitration reactor 15,31 Supply pipe 17,34 Spray nozzle 20 Heat insulation part as heat insulation part 40 Forced cooling section

Continuation of front page (72) Creator Hisao Tanabe Shin Co., Ltd. 125-1 Nishishinmachi, Ota City, Gunma Prefecture Within the experimental research department of the power plant division of Kata Iron Works.

Claims (3)

[Scope of utility model registration request] 1. A urea water supply pipe protruding into an exhaust pipe that leads exhaust gas to a denitrification reactor, a spray nozzle provided at the tip of the supply pipe, and a heat insulating section covering the supply pipe. Exhaust gas reducing agent spray device. 2. A urea water supply pipe protruding into an exhaust pipe that leads exhaust gas to a denitrification reactor, a spray nozzle provided at the tip of the supply pipe, and a forced cooling unit that covers the supply pipe. A spray device for exhaust gas reducing agent. 3. An exhaust gas reducing agent spraying device configured to selectively supply water to a urea water spray nozzle provided inside an exhaust pipe that leads exhaust gas to a denitrification reactor.