JPH115022A - Back washing regeneration type exhaust gas purifying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably regenerate by back-washing over a long period by arranging a catalyst carrying part for combusting a SOF portion in an exhaust gas in an exhaust gas flow-in passage of an exhaust gas purifying filter. SOLUTION: The back-washing regeneration type exhaust gas purifying device is constituted so as to divide a passage into two direction at the front and to exhaust to the outside air at the rear. One of the passage has a filter A1, a valve A2 for intercepting the passage of the exhaust gas flow-out side of the filter A1 and a nozzle A3 for back-washing and ejecting air from the filter A1 to the valve A2. Another passage has also a filter B1, a valve B2 and a nozzle B3. The catalyst carrying part D for combusting the SOF portion in the exhaust gas is arranged in an exhaust gas flow-in passage or carried on the filter A1 and B1 to prevent the contamination by a particulate removed from the filter A1 and B1 at the time of back-washing. As a result, stable regeneration by back-washing are enabled over a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for removing particulates (particulate matter) in exhaust gas discharged from an internal combustion engine.

[0002]

2. Description of the Related Art Recently, it has become a problem that particulates contained in exhaust gas discharged from internal combustion engines such as vehicles such as buses and trucks and construction machines cause harm to the environment and human bodies. The exhaust gas purification device is provided in an exhaust passage of an internal combustion engine, and captures and removes particulates in exhaust gas by a filter.

It is necessary to provide a device for regenerating a filter by removing trapped particulates in an exhaust gas purification device. As a regeneration method using such an apparatus, there has been conventionally known a method in which heat is directly supplied to a filter and the particulate is incinerated by the heat.
However, this method has a problem that the filter is melted by the heat of combustion of the particulates or the filter is damaged by thermal stress.

Further, as a method of regenerating particulates in the filter without burning them, a high-speed airflow is supplied from a direction opposite to the exhaust flow, and after the particulates trapped by the filter are removed by the airflow, a separate airflow is provided. There is known a backwashing regeneration system in which particulates are incinerated in an existing container using an electric heater.

[0005] When this backwashing regeneration system is used, it is not necessary to supply high heat for regeneration directly to the filter. Therefore, there is no damage to the filter due to thermal stress, no ash is deposited in the filter, and the filter is clogged. Is unlikely to occur.

However, when a series of these operations are performed by one filter, the back pressure in the engine exhaust pipe increases in the process of removing particulates, which adversely affects the operability. Therefore, a method of alternately regenerating filters using two sets of filters has been proposed (Journal of the Marine Engineering Society of Japan, Vol. 27, No. 6, (1992-1996)).

In this method, as shown in FIG.
The backwash regenerative exhaust gas purifier includes a filter A (1) and a filter B (4), and the exhaust gas passes through the filter A (1) and the filter B (4) in a normal state. When the regeneration of the filter A is performed, as shown in FIG. 5, the filter A is used to prevent the backwash air from flowing out to the exhaust outlet.
Close the valve (2) between (1) and the exhaust outlet. Next, as shown in FIG. 6, the compressed air is instantaneously injected from the nozzle (3) to remove the particulates accumulated in the filter and to regenerate the filter. After playing the filter,
As shown in FIG. 7, the valve (2) is opened again to perform particulate removal using two ordinary sets of filters.

[0008] In these series of processes, the filter B
Exhaust gas flows through (4) as usual, and particulate removal is performed continuously. The regeneration of the filter B (4) is performed in the same manner as the regeneration of the filter A (1) described above.

The exhaust gas purifying apparatus using the two sets of filters can continuously perform backwashing while removing particulates continuously. Therefore, the exhaust gas purifying apparatus can be used for a long time in a truck traveling a long distance or in a place where ventilation is not possible. It is said that it can be used for an internal combustion engine that operates continuously.

However, the particulates in the exhaust gas include not only carbon but also sulfate (sulfate compound) and SOF (unburned components such as fuel and engine oil). It easily adheres to and accumulates on the purification filter, accumulates over time, causing clogging, and reduces the performance of the exhaust purification filter. The clogging due to the SOF content has a problem that it is difficult to remove the filter from the filter even if the backwashing is performed by injecting the compressed air, which hinders long-term operation.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and an object of the present invention is to provide a backwash regeneration type exhaust gas purifying apparatus capable of performing stable backwash regeneration for a long period of time. It is the purpose.

[0012]

SUMMARY OF THE INVENTION The present invention relates to a method for reducing SO in exhaust gas.
A backwash regenerative exhaust gas purifier characterized in that a catalyst carrier portion for combusting F is disposed in an exhaust gas inflow passage of an exhaust gas purification filter. In the above-mentioned backwashing regeneration type exhaust gas purification apparatus of the present invention, the exhaust gas purification filter comprises:
A passage is provided in each of the exhaust passages separated into two systems, and on the exhaust inflow side of the exhaust gas purification filter, a passage communicating with the two exhaust passages is provided separately from the exhaust inflow passage. The filter may be configured to be provided with a particle collection filter for collecting particles removed by backwashing from the exhaust gas purification filter and burning and removing the particles.

In the backwashing regeneration type exhaust gas purifying apparatus of the present invention, an exhaust gas purifying filter is further provided in each exhaust passage separated into two systems, and the exhaust gas inflow side of the exhaust gas purifying filter is provided. In addition to the exhaust inflow passage, a passage communicating with the two exhaust passages is provided separately. In the passage, particles removed from the exhaust gas purification filter by backwashing are collected and burnt and removed. The exhaust gas purifying filter may be configured to carry a catalyst for burning the SOF in the exhaust gas.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a backwash regenerative exhaust gas purifying apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a normal operation state of a backwash regenerative exhaust gas purifying apparatus according to one embodiment of the present invention, and FIG. FIG. 3 is a diagram showing a normal operation of the backwashing regenerative exhaust gas purifying apparatus according to one embodiment of the present invention and a regenerating state of the filter C1.

[0015] The backwash regenerating exhaust gas purifying apparatus of the present invention is provided in a passage connected to the exhaust side of the internal combustion engine, and the passage is provided with:
It is configured such that it is divided into two directions, a passage A and a passage B, in front of the exhaust purification device, and exhausts to outside air behind the exhaust purification device.

The passage A includes a filter A1, a filter A
No. 1 provided on the exhaust gas outflow side for shutting off a passage and a nozzle A provided between the filter A1 and the valve A2 for injecting backwash air to the filter A1.
The passage B is provided with a filter B1, a valve B2 provided on the exhaust gas outflow side of the filter B1, and a valve B2 for shutting off the passage, and a backwash air provided between the filter B1 and the valve B2. And a nozzle B3 for injecting.

On the other hand, filter A1 and filter B1
A passage C provided separately from the exhaust gas inflow passage on the exhaust gas inflow side and communicating the two exhaust passages is provided with a filter C1 and a valve C2 and a filter C1 provided on either side of the filter C1 for shutting off the passage. And a nozzle C3 provided between the valve C2 and the filter C1 for supplying combustion air to the filter C1. In FIGS. 1, 2, and 3, the catalyst carrier portion D of the present invention is provided in the exhaust inflow side passage of the filter A1 and the filter B2. However, the present invention is not limited to this. Filter A
It is also possible to adopt a configuration in which a catalyst for burning the SOF component in the exhaust gas is carried in the filter 1 and the filter B2.

As shown in FIG. 1, during normal operation of the exhaust gas purifier, exhaust gas is passed through the passages A and B with the valves A2 and B2 open and the valve C2 closed. The particulates in the exhaust from the internal combustion engine are captured by the filter A1 and the filter B1.

As shown in FIG. 2, after the particulates have been captured by the filter A1 for a certain period of time, when the filter A1 is backwashed, the valve B2 is operated while the valve B2 is open, the valve A2 is closed, and the valve C2 is closed. Is opened, backwash air is instantaneously ejected from the nozzle A3 to remove the particulates in the filter A1, and to guide and capture the particulates in the filter C1.

As shown in FIG. 3, after the filter A1 is backwashed, the valve A2 is opened and the valve C2 is closed, and combustion air is supplied from the nozzle C3 to be heated by, for example, a heater. By means, the particulates in the filter C1 are burned, and the air after the removal of the particulates is guided forward of the filter A1, mixed with the exhaust gas of the internal combustion engine, and introduced into the filter A1. These series of operations are a first regeneration process.

On the other hand, after the particulates are captured on the filter B1 for a certain period of time, when the filter B1 is backwashed,
When the valve A2 is opened and the filter A1 is operated, the valve B2 is closed and the valve C2 is opened, and the backwash air is instantaneously injected from the nozzle B3 to remove the particulates in the filter B1. Induce and capture particulates in the filter C1.

After the filter B1 is backwashed, the valve B2 is opened and the valve C2 is closed, and combustion air is supplied from the nozzle C3, and the inside of the filter C1 is heated by, for example, a heater. The particulates are burned, and the air from which the particulates have been removed is guided forward of the filter A1, mixed with the exhaust gas of the internal combustion engine, and introduced into the filter A1. These series of operations are a second regeneration process. In the present invention, the operation of the exhaust gas purification device is continuously performed, and the first regeneration process and the second regeneration process are alternately repeated.

In the backwash regenerating type exhaust gas purifying apparatus of the present invention, a catalyst carrier portion D for burning the SOF in the exhaust gas is disposed on the exhaust gas inflow side of the filter A1 and the filter B1. As shown in FIGS. 1, 2, and 3, the catalyst carrier portion D is not contaminated by the particulates removed from the filter A1 or the filter B1 during the backwashing.
It is arranged in the exhaust gas inflow passage, or the catalyst is carried on the filter A1 and the filter B1.

As the above-mentioned catalyst carrier, those conventionally known can be used, and examples thereof include carriers made of cordierite, mullite, silicon carbide, metal and the like.

The catalyst is not particularly limited as long as it is usually used as an exhaust gas purifying catalyst and can combust the above-mentioned SOF component, and examples thereof include platinum and palladium. The above catalyst is usually 200
Although it functions at a temperature of at least 100 ° C., the temperature of the catalyst in the catalyst carrier portion D or the temperature of the catalyst in the filter A1 and the filter B1 is usually at least 200 ° C. due to the heat of the exhaust gas during operation.

The backwash regeneration type exhaust gas purifying apparatus of the present invention has a SO
Since the F component can be burned by the catalyst, the SOF
It is possible to prevent the components from flowing into the filter A1 and the filter B1, and it is possible to perform stable backwashing regeneration over a long period of time. Further, the pressure loss can be kept constant.

The present invention is used for a backwash regenerative exhaust gas purifying apparatus having two exhaust passages, a passage A and a passage B. However, the present invention is applied to a backwash regenerative exhaust gas purifying apparatus having one ordinary exhaust passage. Can also be applied.

The backwash regenerating type exhaust gas purifying apparatus having the above-described one-system exhaust passage includes, for example, a filter a1, a valve a2 provided on the exhaust outflow side of the filter a1 and a filter a1 and a valve a2 for shutting off the passage. And a passage a having a nozzle a3 for injecting backwash air to the filter a1, and an exhaust inflow passage on the exhaust inflow side of the filter a1, and a filter c
1 and a passage c having a nozzle c3 for supplying combustion air to the filter c1.

In the backwash regenerative exhaust gas purifying apparatus having the above-described one-system exhaust passage, a catalyst carrier portion d for burning the SOF component in the exhaust gas is disposed on the exhaust gas inflow side of the filter a1. The backwashing regenerative exhaust gas purifying apparatus having the above-described one-system exhaust passage can burn the SOF component by the catalyst, so that the SOF component can be prevented from flowing into the filter a1, and the reverse cleaning is stable for a long period of time. Washing and regeneration can be performed. Further, the pressure loss can be kept constant.

[0030]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 A backwash regenerative exhaust gas purification system as shown in FIGS. As the internal combustion engine, a 7000 cc engine was used, and operating conditions were repeatedly set at 500 to 1800 rpm. The backwash air was at a pressure of 8 kg / cm ² and the injection time was 0.1 second. The filter A1 and the filter B1 were made of porous silicon carbide, the partition wall thickness was 0.43 mm, the number of holes was 30 per square inch, the length was 150 mm, and the filter capacity was 3.3 liters. Made of silicon, partition wall thickness 0.43mm, number of holes 30 /
Square inch, length 150mm, filter capacity 0.14
One liter was used.

The heater for burning the particulates captured by the filter C1 is 24V-300W.
Was used. The pressure of the combustion air was 3 kg / cm ² . A catalyst carrier portion D was provided in the exhaust gas inflow passage. The catalyst carrier part D is made of cordierite and has a partition wall thickness of 0.15 m.
m, pore number 400 / square inch, length 178 mm, the surface of the honeycomb body of the filter 5-liter Al ₂ O ₃
After forming a wash coat layer by using the above method, platinum and palladium were respectively supported by a dipping method at a ratio of 1.5 g per liter of filter capacity.

The engine was operated, and the particulate removal operation was continuously performed by the backwashing regeneration type exhaust emission control system of the present invention, and the backwashing of the filter A1 and the filter B1 was performed alternately.

FIG. 11 shows an example of a reproduction sequence of the apparatus. A specific example of the regeneration sequence will be described. In a state where the valve A2 is closed and the valve C2 is opened, after the backwash air is injected from the nozzle A3 to collect the particulates in the filter A1 on the filter C1. The valve A2 is opened, the valve C2 is closed, and air is introduced from the nozzle C3 while the filter C1 is heated to 630 ° C. to burn the particulates for 15 minutes. Then, the valve B2 is closed and the valve C2 is opened. In this state, after the backwash air is injected from the nozzle B3 to collect the particulates in the filter B1 on the filter C1, the valve B2 is opened and the valve C is opened.
2 was flattened, and the operation of injecting air from the nozzle C3 and burning the particulates for 15 minutes while the filter C1 was heated to 630 ° C. was continuously repeated.

The temperature of the catalyst carrier portion D during operation is 250 to
350 ° C. Pressure loss due to backwash regeneration type exhaust emission control device during operation was stable at 1000mmH ₂ O or less. After operation for 1000 hours, the inside of the filter A1 and the filter B1 was visually judged, and almost no particulate matter was deposited.

Example 2 Instead of providing the catalyst carrier portion D, the surfaces of the filter A1 and the filter B1 were coated with Al ₂ O ₃ , and then platinum and palladium were supported by dipping at a rate of 3 g per liter of filter capacity. A backwash regenerative exhaust gas purification system was manufactured in the same manner as in Example 1 except that
Activated. Filter A1 and filter B during operation
The temperature of 1 was 200-300 ° C. The pressure loss due to the backwash regenerative exhaust purification system during operation is 1000 mmH
It was stable below ₂ O. After operation for 1000 hours, the inside of the filter A1 and the filter B1 was visually judged, and almost no particulate matter was deposited.

[0037]

The backwash regeneration type exhaust gas purifying apparatus of the present invention is as described above, so that stable backwash regeneration can be performed over a long period of time.

[Brief description of the drawings]

FIG. 1 is a diagram showing a normal operation state of an embodiment of a backwashing regeneration type exhaust gas purification apparatus of the present invention.

FIG. 2 is a diagram showing a backwashing regeneration type exhaust gas purification apparatus according to an embodiment of the present invention at the time of backwashing.

FIG. 3 is a diagram showing a normal operation and a regeneration state of a filter C1 of one embodiment of a backwash regeneration type exhaust gas purification apparatus of the present invention.

FIG. 4 is a diagram showing a normal operation state of a conventional backwashing regeneration type exhaust gas purification apparatus using two sets of filters.

FIG. 5 is a view showing a state in which a valve on a filter A side of a conventional backwash regenerating type exhaust gas purification apparatus using two sets of filters is closed.

FIG. 6 is a view showing a state of a conventional backwashing regeneration type exhaust gas purification apparatus using two sets of filters when the filter A is backwashed.

FIG. 7 is a diagram showing a conventional backwashing regenerative exhaust gas purifier using two sets of filters in a normal operation restarting state.

FIG. 8 is a schematic diagram of a backwash regenerative exhaust gas purifying apparatus according to the first embodiment.

FIG. 9 is a cross-sectional view of the backwash regenerative exhaust gas purifying apparatus according to the first embodiment.

FIG. 10 is a schematic diagram of a backwash regeneration type exhaust gas purification system according to the first embodiment.

FIG. 11 is a sequence diagram of backwashing of the backwash regenerative exhaust gas purifying apparatus according to the first embodiment.

[Explanation of symbols]

 A1 filter A1 A2 valve A2 A3 nozzle A3 B1 filter B1 B2 valve B2 B3 nozzle B3 C1 filter C1 C2 valve C2 C3 nozzle C3 1 filter A2 valve 3 nozzle 4 filter B 5 valve 6 nozzle 10 air tank 11 air compressor 11 air compressor Solenoid valve 14 Regulator 15 Filter C1 Secondary air for combustion D Catalyst carrier

Claims (3)

[Claims] 1. A backwash regenerative exhaust gas purifying apparatus, wherein a catalyst carrier for burning SOF in exhaust gas is disposed in an exhaust gas inflow passage of an exhaust gas purifying filter. 2. The exhaust purification filter is provided in each exhaust passage separated into two systems, and the exhaust purification filter is provided on the exhaust inflow side of the exhaust purification filter separately from the exhaust inflow passage. 2. The exhaust gas passage according to claim 1, wherein a passage communicating with the exhaust passage is provided, and the passage is provided with a particle collecting filter for collecting particles removed by backwashing from the exhaust gas purifying filter and burning and removing the particles. Backwash regenerative exhaust purification system. 3. An exhaust purification filter is provided in each exhaust passage separated into two systems, and the exhaust purification filter is provided on the exhaust inflow side of the exhaust purification filter separately from the exhaust inflow passage. A passage communicating with the passage is provided, and the passage is provided with a particle collection filter for collecting particles removed by backwashing from the exhaust gas purification filter and burning and removing the particles; A catalyst for burning the SOF component in the exhaust gas is carried on the backwash regenerative exhaust gas purifying device.