JP2006009607A - Urea water storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent strong ammonia odor from leaking out even if a filler hole is opened when refilling urea water in a storage device for urea water to be added as a reducing agent to a selective reduction type catalyst for reduction purification of NO<SB>x</SB>. <P>SOLUTION: This urea water storage device is composed of a tank 1 for storing urea water 2 to be added as the reducing agent to the selective reduction type catalyst for reduction purification of NO<SB>x</SB>, a tank cap 4 for closing the filler hole 3 provided at the upper part of the tank 1, and an incision valve 5 mounted to the filler hole 3 to continuously close an opening even after removing the tank cap 4 and formed with radial cut lines 5a to allow the insertion of a nozzle member for injecting urea water 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a urea water storage device to be added as a reducing agent to a selective reduction catalyst for reducing and purifying NOx.

  Conventionally, diesel engines are equipped with a selective reduction catalyst (selective reduction catalyst) that has the property of selectively reacting NOx with a reducing agent even in the presence of oxygen in the middle of an exhaust pipe through which exhaust gas flows. The required amount of reducing agent is added to the upstream side of the selective catalytic reduction catalyst, and the reducing agent is subjected to a reduction reaction with NOx (nitrogen oxide) in the exhaust gas on the selective catalytic reduction catalyst, whereby NOx emission concentration There is one that can reduce the above.

On the other hand, in the field of industrial flue gas denitration treatment in plants and the like, the effectiveness of a method for reducing and purifying NOx using ammonia (NH ₃ ) as a reducing agent is already widely known. Since it is difficult to ensure safety with respect to traveling with ammonia itself, in recent years, the use of non-toxic urea water as a reducing agent has been studied.

  That is, if urea water is added to the exhaust gas upstream of the selective catalytic reduction catalyst, the urea water is decomposed into ammonia and carbon dioxide under a temperature condition of about 170 ° C. or higher, and the exhaust gas is exhausted on the selective catalytic reduction catalyst. The NOx contained therein is reduced and purified well by ammonia.

  When urea water is used as a reducing agent in this way, urea water is stored in a tank mounted on the vehicle. In the future, urea water is used in the same manner as refueling with a fuel gun at a gas station or the like. It is hoped that there will be a new supply system that can be easily supplied.

In addition, as prior art document information regarding this type of urea water tank, for example, there is Patent Document 1 as shown below.
JP 2003-314252 A

  However, when storing urea water in a tank mounted on a vehicle, the surface temperature inside the tank may be 50 ° C. or higher under conditions where the outside air temperature is high, such as in summer, and in such cases As a result, a part of the urea water was turned into ammonia and turned into gas, and a strong ammonia odor might leak out when the inlet was opened to replenish the urea water.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a urea water storage device that prevents a strong ammonia odor from leaking even when an inlet is opened when urea water is replenished.

  The present invention relates to a tank for storing urea water to be added as a reducing agent to a selective catalytic reduction catalyst for reducing and purifying NOx, a tank cap for closing an inlet provided in the upper part of the tank, and the inlet And an incision valve having a cut line so as to allow the insertion of a nozzle member for continuously injecting urea water even after the tank cap is removed. , Related to

  Thus, in this way, even if the tank cap is opened when the urea water is replenished, the injection port continues to be blocked by the incision valve, and even if the nozzle member for injecting the urea water is inserted into the injection port, Since this nozzle member enters the tank while expanding the cut line of the incision valve, leakage of ammonia odor from the tank is prevented.

  Furthermore, in the present invention, a canister having a ventilation structure is provided in the center portion of the tank cap so as to extend the cut line of the incision valve when it is attached to the inlet so as to face the tank, and the canister is filled with the adsorbent. It is preferable to do.

  In this way, the ammonia gas that accumulates in the gas phase region in the tank is adsorbed by the adsorbent in the canister, and the unique ammonia odor is deodorized. When the tank cap is opened when urea water is replenished Leakage of ammonia odor is further prevented.

  That is, the ammonia gas concentration in the gas phase region in the tank is reduced by being adsorbed by the adsorbent in the canister, so that ammonia gas leaks from a slight gap in the cut line of the incision valve when urea water is replenished. However, it becomes difficult to feel as an ammonia odor because the concentration is already diluted.

  Further, when the canister protrudes from the inner center portion of the tank cap in this way, an air introduction port communicating with the inside of the canister is provided at the outer center portion of the tank cap, and the air introduction port and a pressurized air source outside the tank are provided. Is preferably connected by an air purge line with an on-off valve.

  In such a case, when the on-off valve is opened immediately after starting or stopping the engine, the pressurized air from the pressurized air source is introduced into the air inlet through the air purge line, and is added from the air inlet to the inside of the canister. The compressed air is blown and the droplets adhering to the adsorbent are blown off, and the adsorbent in the canister is held in a dry state.

  That is, if the adsorbent in the canister continues to adsorb ammonia gas and becomes wet and wet, the adsorbent's ability to adsorb ammonia gas will be lost. It is possible to keep the adsorbent in a dry state as much as possible by blowing it off with pressurized air and returning it to the liquid phase region in the tank.

  According to the urea water storage device of the present invention described above, various excellent effects as described below can be obtained.

  (I) According to the invention described in claim 1 of the present invention, even when the tank cap is opened when urea water is replenished, or when the nozzle member for injecting urea water is inserted into the inlet, the incision valve is used for injection. Since the inlet can be kept blocked, strong ammonia odor can be kept from leaking from the tank.

  (II) According to the invention described in claim 2 of the present invention, the concentration of ammonia gas in the gas phase region in the tank can be reduced by adsorbing to the adsorbent in the canister. The leakage of ammonia odor when the tank cap is opened for replenishment can be prevented more reliably.

  (III) According to the invention described in claim 3 of the present invention, even if the adsorbent in the canister continues to adsorb ammonia gas and becomes wet and wet, the liquid adhering to the adsorbent Since it is possible to keep the adsorbent in a dry state as much as possible by blowing off the droplets with pressurized air, it is possible to maintain a high adsorption ability of ammonia gas by the adsorbent.

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

  1 to 6 show an example of an embodiment of the present invention. In the figure, 1 is a tank for storing urea water 2 to be added as a reducing agent to a selective reduction catalyst for reducing and purifying NOx. The inlet 3 provided in the upper part of the tank 1 is closed by screwing the tank cap 4, and the tank 1 contains urea water to a selective reduction catalyst (not shown). The water pipe which sends out 2 will be inserted.

  As shown in FIGS. 2 and 3, the injection port 3 of the tank 1 can allow insertion of a nozzle member X that continues to close the opening and removes the urea water 2 even after the tank cap 4 is removed. A rubber incision valve 5 with a radial cut line 5a is attached, and the incision valve 5 shown here has a shape that is recessed in a bowl shape toward the inside of the tank 1. The hole 5b for tearing is formed in the outer end of each cut line 5a.

  Further, as shown in FIGS. 4 and 5, in the inner center portion of the tank cap 4, the cut line 5 a of the incision valve 5 is pushed and expanded toward the tank 1 when the tank cap 4 is attached to the inlet 3. A canister 6 having a structure is projected, and the canister 6 is filled with an adsorbent 7 (having a high substance adsorbing ability) such as activated carbon having a large surface area per unit volume.

  On the other hand, an air introduction port 8 communicating with the inside of the canister 6 is provided at the center of the outside of the tank cap 4, and an opening / closing valve 10 is provided between the air introduction port 8 and the air tank 9 outside the tank 1. The air purge line 11 is connected (see FIG. 1).

  For the purpose of connecting the air purge line 11 as described above, the screwing of the tank cap 4 to the inlet 3 is preferably completed at a relatively small rotation angle of about 90 °.

  Thus, if the urea water storage device is configured in this way, as shown in FIG. 3, even if the tank cap 4 is opened when the urea water 2 is replenished, the injection port 3 continues to be blocked by the incision valve 5, As shown in FIG. 6, even if the nozzle member X for injecting the urea water 2 is inserted into the injection port 3, the nozzle member X enters the tank 1 while expanding the cut line 5 a of the incision valve 5. The leakage of ammonia odor from the inside is prevented.

  Further, as shown in FIG. 5, when the tank cap 4 is attached to the injection port 3, the canister 6 inside the tank cap 4 expands the cut line 5 a of the incision valve 5 to enter the tank 1. Since it enters, the ammonia gas accumulated in the gas phase region in the tank 1 is adsorbed by the adsorbent 7 in the canister 6 to deodorize the unique ammonia odor, and the tank cap 4 is opened when the urea water 2 is replenished. Leakage of ammonia odor at the time is further prevented.

  That is, the concentration of ammonia gas in the gas phase region in the tank 1 is reduced by being adsorbed by the adsorbent 7 in the canister 6, so that when the urea water 2 is replenished, from the slight gap of the cut line 5 a of the incision valve 5. Even if ammonia gas leaks out, it becomes difficult to feel it as an ammonia odor because its concentration has already been diluted.

  Further, for example, when the opening / closing valve 10 is set to open by a control command from an engine control computer (not shown) immediately after the engine is started or stopped, the pressurized air 12 from the air tank 9 is introduced into the air through the air purge line 11. The air is introduced into the port 8, the pressurized air 12 is blown into the canister 6 from the air inlet 8, and the droplets adhering to the adsorbent 7 are blown off, and the adsorbent 7 in the canister 6 is held in a dry state. It will be.

  In other words, if the adsorbent 7 in the canister 6 continues to adsorb ammonia gas and becomes wet and wet, the adsorbent 7 loses its ability to adsorb ammonia gas. It is possible to keep the adsorbent 7 in a dry state as much as possible by blowing off the droplets with the pressurized air 12 and returning them to the liquid phase region in the tank 1.

  Therefore, according to the above-described embodiment, the incision valve 5 allows the injection port 3 to be opened even when the tank cap 4 is opened when the urea water 2 is replenished or when the nozzle member X for injecting the urea water 2 is inserted into the injection port 3. Since the strong ammonia odor can be kept from leaking out of the tank 1 and adsorbed by the adsorbent 7 in the canister 6, ammonia in the gas phase region in the tank 1 can be maintained. The concentration of the gas can be reduced, whereby the leakage of ammonia odor when the tank cap 4 is opened for replenishment of the urea water 2 can be prevented more reliably.

  Further, even if the adsorbent 7 in the canister 6 continues to adsorb ammonia gas and becomes wet and wet, the adherent 7 is blown off with the pressurized air 12 by adhering droplets adhering to the adsorbent 7. Can be kept in a dry state as much as possible, so that the adsorption ability of ammonia gas by the adsorbent 7 can be maintained high.

  In addition, the urea water storage apparatus of this invention is not limited only to the above-mentioned example, Of course, various changes can be added within the range which does not deviate from the summary of this invention.

It is the schematic which shows an example of the form which implements this invention. It is a perspective view which shows the detail of the incision valve with which the injection inlet of FIG. 1 was mounted | worn. It is sectional drawing which shows the state of an incision valve when a tank cap is removed. It is a perspective view which shows the state which looked up at the tank cap from the bottom. It is sectional drawing which shows the state of an incision valve when a tank cap is mounted | worn. It is sectional drawing which shows the state of an incision valve when a nozzle member is inserted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tank 2 Urea water 3 Inlet 4 Tank cap 5 Cutting valve 5a Cut line 5b Ramp hole 6 Canister 7 Adsorbent 8 Air inlet 9 Air tank (Pressurized air source)
10 On-off valve 11 Air purge line 12 Pressurized air X Nozzle member

Claims (3)

  A tank for storing urea water to be added as a reducing agent to the selective catalytic reduction catalyst for reducing and purifying NOx, a tank cap for closing an inlet provided in the upper part of the tank, and a tank cap mounted on the inlet A urea water storage device comprising an incision valve having a cut line so as to permit the insertion of a nozzle member that continues to close the opening even after the tank cap is removed and to inject urea water.   A canister having a vent structure is provided in the center of the tank cap so as to extend the cut line of the incision valve at the time of mounting to the inlet and face the tank, and the canister is filled with an adsorbent. Item 4. The urea water storage device according to Item 1.   An air introduction port that communicates with the inside of the canister is provided in the center of the outside of the tank cap, and the air introduction port and a pressurized air source outside the tank are connected by an air purge line with an on-off valve. The urea water storage device according to 2.

Images