KR960002520B1 - Particle material removing method of exhaust gas - Google Patents

Abstract

The removal of particulate matters is conducted using both fuel additive-containing diesel and a filtering trap, or a noble metal-coated catalytic trap alone. And heat-insulating material or a housing of heat-insulating material is attached onto the exhaust discharge pipe from engine exhaust part to the filtering trap or the catalytic trap. The fuel additive, of which the concentration is 10-1000ppm, is at least one selected from oil-soluble transition metal compounds (Mn, Fe, Ni, Ce, Co, etc.), alkaline earth metal compounds (Ba, Ca), and lanthanide metal compounds (Ce, etc.).

Description

Removal method of particulate matter in diesel vehicle exhaust

The present invention relates to a method for removing particulate matter in diesel vehicle exhaust gas.

In Korea, where the proportion of diesel vehicles is 42% of total vehicles, particulate matter emitted by the exhaust gas of diesel vehicles is a major air pollution factor. Particulate matter discharged from the exhaust gas of diesel vehicles is unburned carbon particles with an average diameter of about 0.3 μm. When the concentration in the exhaust gas exceeds the environmental standard value (the smoke limit of 40% for a heavy duty vehicle in 1993: As well as causing severe discomfort, it is the cause of harmful diseases such as cancer. Therefore, in the case of heavy duty diesel vehicles, in 1996, 0.67 g / Hp. Hour, United States since 1994, 0.1g / Hp. The company plans to strengthen regulations with Hour, but various studies are being actively conducted since the technology that satisfies this has not been commercialized.

The development direction of the removal of particulate matter includes the suppression of the production of unburned materials through the high efficiency of the engine, the improvement of the combustion performance using the fuel additive, and the post-treatment technology of the particulate matter. It is possible to fundamentally reduce harmful substances such as particulate matter and soot by increasing the combustion effect in Esau, but it is excessively expensive, and it is not easy to be completely suppressed by the current technology level, and is finally discharged through exhaust gas. It is true. The post-treatment technology is composed of a filtration technology for filtering particulate impurities in exhaust gas and a technology for regenerating the filter material by burning the filtered particulate matter. The filtration technology has an excellent ability to effectively collect particulate matter in exhaust gas. The research focuses on the selection of filter media and its application to actual vehicles.

However, the development of regeneration technology for damaging the filter medium and degrading the engine performance by increasing the back pressure of the engine exhaust passage due to the filtration of particulate matter and effectively burning the deposited filter medium of particulate matter at high temperature conditions. It became necessary.

The most widely known regeneration technology to date is a method of supplying secondary energy by using a burner, a heater, or the like by regenerating the exhaust gas by raising the exhaust gas temperature, and adding a catalyst to the fuel or depositing the catalyst on the filter medium. have.

According to US Patent Nos. 3951613, 3761729, and Japanese Patent Publication No. 86225282, fuel, organic metal additives such as copper, selium, manganese, silicon, and iron are injected into the fuel to regenerate the filter material. It is known that when the additive injection amount is increased and the regeneration performance is changed, and the additive injection amount is increased, a small amount of some is discharged to the atmosphere through the filter medium together with the doubling gas, causing secondary pollution.

Korean Patent Publication No. 89-3594 and US Pat. No. 5083427 report a method of depositing a noble metal catalyst such as platinum, palladium, rhodium, and the like on a filter medium and mounting it on an engine exhaust pipe to regenerate the filter medium. However, this approach has several disadvantages. That is, particulate matter is not effectively combusted at an ordinary diesel engine exhaust gas temperature of, for example, about 300 ° C. Diesel engine exhaust gas temperature may be raised to 500 ℃ or more, but most of the temperature is 300 ℃ or less in general. For example, except for intermittent high speed operation such as city running, the temperature is typically 300 ° C. or lower since it is a slow running speed. Therefore, in the case of using the catalyzed filter medium, particulate matter is not sufficiently burned at low exhaust gas temperature and excessively accumulated, thereby increasing the exhaust gas discharge pressure, and excessive carbon material is rapidly burned, causing the filter medium to be damaged by excessive temperature rise. Is known to be a big problem in practical application.

The present inventors have conducted extensive research to solve the above problems and found that the temperature of the exhaust gas flowing through the engine exhaust pipe is kept lower than the engine exhaust pipe in the filter trap due to heat loss. On the basis of this, the exhaust pipe was completed by improving the insulation system.

It is therefore an object of the present invention to provide a method of significantly improving the regeneration efficiency, which is a problem of the above technique, by maintaining the temperature in the exhaust pipe at an appropriate temperature at which the catalyst operates without quenching or supplying secondary energy.

In order to achieve the above object, the method of the present invention removes particulate matter by simultaneously using diesel and filter traps containing a fuel additive or by using a catalyst-coated filter trap (hereinafter, referred to as a mat trap) alone. By mounting a housing containing a heat insulating material or a heat insulating material to the exhaust pipe leading to the filter trap or up to the catalyst trap is configured to increase the temperature of the filter trap to remove particulate matter.

The filter trap used in the present invention is useful for filtration of diesel particulate matter such as ceramic pong, ceramic fiber filter, open flow ceramic honeycomb, well flow honeycomb monolith, open flow metal honeycomb, metal foam, metal mesh, etc. All known three-dimensional structures can be used and there is no particular limitation.

One or two of the fuel additives used in the present invention are oil-soluble transition metal compounds (Mn, Fe, Ni, Ce, Cu, Co, etc.), alkaline earth metal compounds (Ba, Ca), and lanthanide metal compounds (Ce, etc.). When added more than one species to the diesel can be used for all fuel additives known to be useful for suppressing soot, there is no particular limitation.

The catalyst trap used in the present invention is produced by coating one or two or more kinds of white metals such as platinum, rhodium, and palladium on the filter traps, and a three-dimensional structure already known to be useful for filtration and regeneration of diesel particulates may be used. There is no special limitation to this.

Insulation materials used in the present invention is asbestos, mineral fibers, cell glass, calcium silicate, silica airgel, diatomite, etc. In general, there is no particular limitation to materials that are known to have excellent heat insulation performance even at high temperatures of 300 ° C or higher. From the engine exhaust pipe to the filter trap or the catalyst trap, a housing containing a heat insulating material or a heat insulating material was mounted, and diesel containing a fuel additive was injected.

When the fuel additive and the filter trap are used at the same time as described above, the temperature inside the trap is increased by 50 ° C to 150 ° C, so that regeneration is easily performed even at low speed and low load, and even when only the catalyst trap is used, Regeneration could easily occur without accumulation, minimizing damage to the filter media due to excessive back pressure changes.

Hereinafter, the configuration and effects of the present invention will be described in detail with reference to Examples and Comparative Examples, but the examples do not limit the scope of the present invention.

Example 1

Particle trap dynamometer experiments were conducted to measure particle emissions of diesel fuel mixtures. A Peter AV-B supercharged single cylinder diesel engine was used. The engine was connected to a coated EX-54 ceramic monolithic filter. Asbestos tape (Pack Non Drop Worp from Cheil Chemical Co., Ltd.) from the engine exhaust pipe to the filter trap was wound to a thickness of 5 mm. 15 L of a diesel composition containing 500 ppm of cerium naphthenate is prepared. Inject the diesel fuel composition into the engine and record the operating power at ignition. By inserting the existing fuel, the engine bypass valve is shut off under normal operating conditions of 2250 ± 20rpm, coolant temperature 100 ± 2 ℃, oil temperature 90 ± 2 ℃, oil pressure 2.5 ± 0.2bar, air inlet pressure 2280 ± 15mbar. Open the filter trap valve. As the particles released from the engine accumulate in the filter, the pressure between the engine and the filter trap increases. Operate the chute valve and increase the power by 0.6KW every 5 minutes to measure the temperature and pressure at the end of the trap until the moment the pressure decreases rapidly. At this time, the relationship between the regeneration time and the temperature, pressure is shown in Table 1.

[Comparative Example]

After removing the asbestos tape in the apparatus of Example 1, the experiment was carried out under the same conditions as in Example 1, wherein the time of regeneration occurs, and the change in temperature and pressure is shown in Table 2 below.

TABLE 1

TABLE 2

As can be seen from Tables 1 and 2, the method of attaching the insulation to the diesel particulate matter removal apparatus using the fuel additive and the filter medium of the present invention can be seen that the regeneration occurs easily in a short time even at low power and low back pressure. .

Example 2

The wall flow honeycomb monolith was equipped with alumina and alumina-based platinum filter and palladium-based catalyst filter, respectively, in a trap, and then the Peter AV-B supercharger was mounted on the exhaust pipe of a single-cylinder diesel engine. The housing surrounding the catalyst trap from the engine exhaust pipe to the catalyst trap was fabricated and attached so that the filling thickness was 8 mm, and then calcium silicate powder was filled in the space between the exhaust device and the housing from the exhaust pipe to the catalyst trap. Using the additive-free diesel as a test fuel was tested under the same operating conditions as in Example 1, wherein the regeneration time, temperature, pressure change relationship is shown in Table 3.

Comparative Example 2

After the calcium silicate housing was removed from the apparatus of Example 2, the experiment was carried out under the same conditions as in Example 2, and the relationship between the time at which regeneration occurred, the temperature, and the pressure change was shown in Table 4 below.

TABLE 3

TABLE 4

As can be seen from Tables 3 and 4, the method of attaching the insulating material to the apparatus for removing diesel particulate matter using only the catalyst trap of the present invention alone is low power, so that regeneration occurs easily in a short time even at low back pressure, so the rapid change in back pressure It can be seen that the damage caused by the filter medium can be minimized. Therefore, it is possible to maintain the temperature at which the catalyst trap is regenerated under low-speed and low-load operating conditions by simply attaching heat insulator when applied to the actual vehicle, thus eliminating many devices necessary for supplying secondary energy. There is an advantage that can be made.

Claims (7)

In order to remove particulate matter by using a diesel and fuel trap containing a fuel additive at the same time or by using only the catalyst trap alone, the exhaust pipe from the engine exhaust pipe to the filter trap and the catalyst trap contain a heat insulating material or a heat insulating material housing. To remove particulate matter in diesel vehicle exhaust gas. The fuel additive of claim 1, wherein the fuel additive is one of oil-soluble transition metal compounds (Mn, Fe, Ni, Ce, Cu, Co, etc.), alkaline earth metal compounds (Ba, Ca), and lanthanide metal compounds (Ce, etc.). Or at least two kinds of particulate matters in the diesel vehicle exhaust gas. The method for removing particulate matter in a diesel vehicle exhaust gas according to claim 1, wherein the fuel additive concentration is 10 to 1000 ppm. The diesel vehicle according to claim 1, wherein the filter trap is made of one of a filter material of ceramic foam, ceramic fiber filter, opflow ceramic honeycomb, wallflow honeycomb monolith, openflow metal honeycomb, metal foam, and metal mesh. A method for removing particulate matter in exhaust gas. The method of claim 1, wherein the catalyst trap is a metal catalyst deposited on the filter medium of claim 4 to remove particulate matter in the diesel vehicle exhaust gas. The method of removing particulate matter in a diesel vehicle exhaust gas according to claim 5, wherein the metal catalyst is one or two or more kinds of platinum metals such as platinum, rhodium, and palladium are deposited. 2. The diesel vehicle exhaust gas according to claim 1, wherein the heat insulating material comprises asbestos, mineral fiber, cell glass, calcium silicate, diatomite, and minerals of one kind or a mixture of two or more kinds of fiberglass. How to remove particulate matter.