KR20060004880A - Exhaust gas purification system of nano-metallic doc/nox catalyst combined with electric discharge filter in diesel automobile - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel vehicle exhaust purification apparatus coupled with a DOC / NOx catalyst containing nano metal particles and a discharge filter. In particular, an oxide catalyst slurry composed of Pt, TiO 2, and gamma alumina on a ceramic honeycomb is fire-coated. Next, Cu (NO ₃ ) ₂ -3H ₂ O, CuO, and gamma-shaped alumina carriers were baked on the nano-oxidation catalyst and the ceramic honeycomb impregnated with Pt and Pd nanometal particles, followed by calcination, followed by Cu, Au, and Ag nanometals. DeNo _x nanoreduction catalyst impregnated with particles, characterized in that composed of a discharge filter by a high voltage corona discharge. Using the diesel three-way catalytic filter produced in the present invention, the exhaust gas from the engine is refined in a high voltage discharge filter, PM component is oxidized in a DOC nano oxidation catalyst, and CO is converted into CO ₂ , and NO _x in a DeNO _x nano reduction catalyst. It has a function of preventing air pollution by reducing the component to N ₂ .

As described above, the present invention provides an effect of reducing the diesel exhaust gas contained in the nano soot particles in a state in which Pt, Pd, Cu, Au, Ag nano metal particles having a size of 5-15 nm are coated.

Exhaust gas purification system of nano-metallic nano-catalyst combined with electric discharge filter in diesel automobile}

Description

Exhaust gas purification system of nano-metallic DOC / NOx catalyst combined with electric discharge filter in diesel automobile}

1 is a photograph of a DOC catalytic filter embodiment prepared in the present invention

Figure 2 is a real picture of the diesel NO _x purification reduction catalyst filter produced in the present invention

Figure 3 is a real photograph made of a catalytic filter for diesel DOC / NO _x purification in the present invention

Figure 4 is a plastic heat treatment characteristic diagram of the diesel DOC / NO _x catalyst filter in the present invention

Figure 5 is an electron micrograph of the catalytic filter for diesel DOC / NO _x purification without inserting nanoparticles in the present invention

FIG. 6 is an electron micrograph of a diesel DOC / NO _x purification catalyst filter inserted with nanoparticles and fired at 600 ° C. according to the present invention.

Figure 7 is an electron micrograph of the catalytic filter for diesel DOC / NO _x purification by inserting the nanoparticles in the present invention and calcined at 800 ℃

Figure 8 is a photograph of the discharge filter produced in the present invention

9 is a photographic view of a purification device combining the discharge filter and the DOC / NO _x filter produced in the present invention

10 is a light absorption photograph of soot before and after the discharge filter and DOC / NO _x filter for a diesel engine of the present invention.

11 is a soot performance characteristics of the purifier combined the discharge filter for the diesel engine and DOC / NO _x filter of the present invention.

12 is a diagram showing the NO _x component reduction characteristics of the DOC / NO _x filter for a diesel engine of the present invention.

Figure 13 is a CO component reduction characteristics of the DOC / NO _x filter for a diesel engine of the present invention

* Description of the symbols used in the main parts of the drawings *

1: Nano DOC Catalytic Filter 2: Nano NO _x Catalytic Filter

3: nano DOC / NO _x catalytic filter 4: discharge filter

5: discharge filter power

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel vehicle exhaust purification apparatus coupled with a DOC / NOx catalyst containing nano metal particles and a discharge filter. In particular, an oxide catalyst slurry composed of Pt, TiO 2, and gamma alumina on a ceramic honeycomb is fire-coated. Next, Cu (NO ₃ ) ₂ -3H ₂ O, CuO, and gamma-shaped alumina carriers were baked on the nano-oxidation catalyst and the ceramic honeycomb impregnated with Pt and Pd nanometal particles, followed by calcination, followed by Cu, Au, and Ag nanometals. DeNo _x nanoreduction catalyst impregnated with particles, characterized in that composed of a discharge filter by a high voltage corona discharge. Using the diesel three-way catalytic filter produced in the present invention, the exhaust gas from the engine is refined in a high voltage discharge filter, PM component is oxidized in a DOC nano oxidation catalyst, and CO is converted into CO ₂ , and NO _x in a DeNO _x nano reduction catalyst. It has a function of preventing air pollution by reducing the component to N ₂ .

Due to the regulation of carbon dioxide emissions under the Kyoto Climate Convention, diesel passenger cars, which have relatively less carbon dioxide emissions than gasoline passenger cars, are preferred internationally, and diesel cars have begun to be launched in Korea. However, unlike a gasoline engine, a diesel engine has a high pressure and the engine temperature increases due to high pressure ignition, and nitrous oxide (NO _x ) in which oxygen and nitrogen are chemically combined in the air is contained in the exhaust gas, which is very harmful to the human body as a carcinogen. Particulate matters (PM) from diesel engines are also being reduced to nanoparticles by high-pressure injection of fuel in a common-rail manner. Other materials from diesel engines include hydrocarbons (HC) and carbon monoxide (CO) due to incomplete combustion of diesel fuel, which contains more carbon than gasoline and has a relatively high polymerized polymer.

Recently, there are two ways to reduce diesel emissions, namely pre-combustion treatment and post-combustion treatment. The former includes methods for improving fuel injection, combustion chamber shape, and fuel refining. The latter includes diesel particulate filter (DPF), and diesel oxidation converter (DOC) to reduce HC and CO. In recent years, research on the reduction of harmful substances and NO _x reduction in diesel engine exhaust gas using plasma has been actively conducted.

In particular, engine aftertreatment devices for reducing NO _x emissions include HC DeNO _x catalytic conversion, NO _x storage catalytic conversion and SCR NO _x conversion. The most preferred method is NO _x storage catalytic conversion, which has been applied to lean burn gasoline engines and is applied to diesel engines. If the air-fuel ratio λ is greater than 1, the NO _x accumulation process is continued, and if it is less than 1, NO _x is regenerated to N ₂ using the HC, CO, and H ₂ exhaust gas components intermittently increased.

Conventional techniques used to purify the exhaust gas in such a NO _x catalytic conversion method include Pt, Li, alumina and CO / in ceramic honeycomb in the method of producing NO _x catalyst with Engelhard (US 09/634228) SO _x resistance. The catalyst slurry powder composed of Al oxide was washed and then calcined in air, as well as alkali metal of barium oxide or strontium oxide was used as the sulfur catalyst composite.

Kia Motors (Patent 10-0231532) uses a cordierite (cordierite: 2MgO-2Al ₂ O ₃ ) honeycomb with alumina and titanium oxide (TiO ₂ ) and platinum or rhodium ion exchange zeolite (Pt- , Rh-ZSM-5) was washcoated, and the Pt: Rh ratio was impregnated with 1-3 g / l in the range of 2-10: 1. This is because it has the characteristic of decomposing nitrogen oxides in the excess oxygen atmosphere in the case of having a perovskite crystal structure in a similar precious metal ion, especially a copper (Cu) ion exchange zeolite or a composite oxide containing a metal oxide and a supported metal. .

In addition, Samsung Electro-Mechanics (Patent 10-0446600) supported copper oxide (CuO) as a catalyst component and cocatalyst component of Pt and Pd in zirconia carrier (Fe-ZrO ₂ ) impregnated with iron as a catalyst for purifying nitrogen oxides. As such, although nitrogen oxides can be reduced by using a copper component, there is a disadvantage in that the conversion efficiency is low to be practical.

The present invention has been made in view of the conventional technical problems, and an object of the present invention is to manufacture a diesel vehicle exhaust purification apparatus combined with a discharge filter and a DOC / NOx catalyst containing nano metal particles, such as Pt, Pd, Cu, Au. The nanocatalyst filter of the oxidation catalyst and the reduction catalyst is prepared using 5-15 nm nanometal particles such as, Ag and metal oxide nanoparticles such as TiO ₂ and CuO. The purpose is to fabricate nanocatalyst filters in which these nanoparticles are supported on Cu, Cu (NO ₃ ) ₃ 3H ₂ O, and oxides TiO ₂ and CuO.

In addition, DOC / containing nano metal particles, characterized in that used in the construction of a diesel exhaust system to remove the PM, NOx, CO or HC at the same time as a diesel three-way catalyst by combining such oxidation and reduction catalyst with the discharge filter. The present invention provides a diesel vehicle exhaust purification apparatus combined with a NOx catalyst and a discharge filter.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. This preferred embodiment enables a better understanding of the objects, features and advantages of the present invention.

Hereinafter, with reference to the accompanying drawings it will be described in detail a preferred embodiment of the diesel vehicle exhaust purification apparatus combined with a DOC / NOx catalyst and a discharge filter containing a nano-metal particles according to the present invention.

1 is a photograph of a DOC catalytic filter embodiment prepared in the present invention. The manufacturing process of this oxidation catalyst 1 is as follows. Cordierite (2MgO-2Al ₂ O ₃ -5SiO ₂ ) honeycomb with Al ₂ O ₃ and 2-20㎛ size of gamma phase Pt 5-20wt%, Pd 5-20wt%, TiO ₂ 5-10wt% The prepared metals and metal oxides were washed, dried and calcined at 600-800 ° C. for 2-5 hours in an electric furnace. The calcined oxidation catalyst was loaded with colloidal Pt 2 mg / l, Pd 2 mg / l, and TiO ₂ 3 mg / l together in an aqueous solution, and then heated to 400-600 ° C. A fired oxidation catalyst device was produced.

Figure 2 is a real picture of the diesel catalyst produced by NO _x purification catalyst for purification in the present invention. The production process of such a reduction catalyst (2) is as follows. Cordierite (2MgO-2Al ₂ O ₃ -5SiO ₂ ) honeycomb with Al ₂ O ₃ and 2-20 ㎛ size gamma phase CuO 5-15wt% for alumina, Cu (NO ₃ ) ₂ -3H ₂ O 5 Metal oxides and organometals contained in -15 wt% and 3-10wt% of indium acetate were washed and dried, and then fired at 600-800 ° C. for 2-5 hours in an electric furnace. The oxidation catalyst calcined in one step was further loaded with Cu 2 mg / l, Ag 2 mg / l, and Au 3 mg / l in a colloidal nanometal particle of 5-15 nm in an aqueous solution, followed by 400-600 ° C. A fired reduction catalyst filter was produced.

Figure 3 is a real photograph of the catalyst filter for diesel DOC / NO _x purification in the present invention. The manufacturing process of such an oxidation / reduction coupling catalyst 3 is as follows. Cordierite (2MgO-2Al ₂ O ₃ -5SiO ₂ ) honeycomb with GaA phase Al ₂ O ₃ and 2-20㎛ size for Pt 5-20wt%, Pd 5-20wt%, TiO ₂ 5-10wt, respectively %, CuO 5-15wt%, Cu (NO ₃ ) ₂ -3H ₂ O 5-15wt%, Indium acetate 3-10wt% was washed with metal oxide and organometallic and dried to 600-800 ℃ in an electric furnace Fire for 2-5 hours. The catalyst calcined in the first step was again subjected to 5-10 nm size of colloidal nanometal particles Pt 2 mg / l, Pd 2 mg / l, TiO ₂ 3 mg / l, Cu 2 mg / l, Ag 2 mg / l, Au 3 mg / l were supported together in an aqueous solution, and then an oxidation / reduction coupling type catalyst filter calcined at 400-600 ° C. was prepared.

4 is a firing heat treatment characteristic diagram of the diesel DOC / NO _x catalyst filter in the present invention. The residual moisture was removed at 100 ° C, the organic solvent was removed at 420 ° C, and maintained at two firing temperatures of 600 ° C and 800 ° C for 1.5-2 hours, and the atmosphere of the electric furnace was 760 Torr at atmospheric pressure. Was maintained.

Figure 5 is an electron micrograph of the catalyst filter for diesel DOC / NO _x purification without inserting nanoparticles in the present invention. Even SEM images with high magnification do not form particulate structures and show irregular amorphous structures.

FIG. 6 is an electron micrograph of a diesel DOC / NO _x purification catalyst filter inserted with nanoparticles and fired at 600 ° C. according to the present invention. It can be seen that the finer nanoparticles are formed in the SEM photograph at a high magnification.

FIG. 7 is an electron micrograph of a diesel DOC / NO _x purification catalyst filter inserted with nanoparticles and fired at 800 ° C. according to the present invention. It can be seen that in the SEM image at high magnification, fine particles having a fine nano-size are formed, and the particle size becomes larger and larger than when fired at 600 ° C.

8 is a photographic view of a discharge filter produced in the present invention. The high-voltage discharge plate has a pair of anode pins and cathode holes, and the arrangement of the holes has a hexagonal shape. Such a discharge filter 4 is provided in front of the catalyst to refine the PM particles, thereby making it easier to pass through the catalyst honeycomb holes and bringing the particles into contact with the surface to increase the catalytic reaction efficiency.

9 is a photographic view of a purification apparatus combining the discharge filter and the DOC / NO _x filter manufactured in the present invention. The case is applied to the Musso model of Ssangyong Motor. The voltage applied to the discharge filter power source 5 may vary from 1-5 kV DC, and the maximum current may flow up to 50 mA. A discharge filter is coupled to the engine and an oxidation / reduction catalyst filter is connected to the rear of the discharge filter.

10 is a light absorption photograph of soot before and after the diesel engine discharge filter and DOC / NO _x filter of the present invention. It shows the color change of soot at the rear part (a) connected to the engine, the part (b) passing through the discharge filter, and the tube outlet (c) through the catalyst filter. The rear part of the engine absorbs all colors from visible light with a wavelength of 400-700 nm, resulting in a dark black color. The rear part of the discharge filter softens the color density, and the rear part of the catalyst filter turns completely gray. . The decrease in smoke level can be confirmed.

11 is a soot performance characteristic diagram of a purification apparatus combining the diesel engine discharge filter and the DOC / NO _x combined filter of the present invention. Actual vehicle measurements were made using the sputum-free vehicles of the Ssangyong Motor produced in 1995, and the smoke level was 40-45% for vehicles with silencer only. When only one of the discharge filter or the catalyst filter was measured, the soot amount was measured in the range of about 25%. When both filters were operated simultaneously, the soot amount was observed in the range of 15-20%. The discharge filter serves to reduce the smoke by miniaturizing the PM.

In the present invention, the surface area of the catalytic reaction was increased by miniaturizing the oxidation catalyst and the surface of the NO _x catalyst carrier using nano metal colloid particles of 5-15 nanometers, and chemical conversion by reacting with each other using a CO oxidation catalyst and a NOx reduction catalyst. Induced. The following equation is a reaction equation in which the CO, HC, NO components react with each other in the three-way catalyst and are oxidized / reduced into CO ₂ , H ₂ O and N ₂ .

NO + CO → 1 / 2N ₂ + CO ₂ (1)

(2m + n / 2) NO + CmHn → (m + n / 4) N ₂ + n / 2H ₂ O + mCO ₂ (2)

NO + H ₂ → 1 / 2N ₂ + H ₂ O (3)

12 is a diagram showing the reduction of NO _x component of the DOC / NO _x filter for a diesel engine of the present invention. The engine was measured while idling at 3000 rpm. When the purifier without having to attach the muffler mounting only NOx exhaust concentration is 230-250 ppm and the other hand if the filter is attached to the catalyst NO _x emission concentration is lowered as it can be seen that 190-200 ppm.

13 is a diagram showing the CO component reduction characteristics of the DOC / NO _x filter for a diesel engine of the present invention. The engine was measured while idling at 3000 rpm. It can be seen that the CO emission concentration is 150-165 ppm when measured with only a silencer attached without a purification device, whereas it is reduced to 110-120 ppm when a catalytic filter is attached.

As described above, the present embodiment can reduce PM, NOx, and CO emissions of diesel engines by fabricating a diesel vehicle exhaust purification apparatus combined with a DOC / NOx catalyst filter and a discharge filter including nano metal particles. In particular, by securing a process for producing a nanocatalyst filter, an oxidation catalyst filter or a reduction catalyst filter may be used alone or in accordance with a use, and a combined catalyst filter may be manufactured.

In addition, it is obvious that the present invention may be modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments should fall within the appended claims of the present invention.

From the above description, the diesel vehicle exhaust purification apparatus combined with the DOC / NOx catalyst filter and the discharge filter including the nano metal particles of the present invention, when the catalyst material is supported on a conventional oxidation catalyst or reduction catalyst, Impregnation maximizes the contact area of the catalyst to the formation of nanosized particulates and increases the catalytic conversion efficiency. In addition, by adopting a diesel engine's common rail type fuel injection system, a nanocatalyst filter was produced to efficiently convert nanoparticles into PM particles, and an exhaust purifier was installed to perform a diesel three-way catalyst in combination with a discharge filter. Produced. Through the above invention, it is possible to implement a nano-catalyst filter having a high efficiency of exhaust reduction in a diesel passenger car.

Claims (3)

In a diesel vehicle exhaust purification apparatus combined with a DOC / NOx catalyst filter and a discharge filter containing nano metal particles, A first step of fabricating an oxidation catalyst filter which washes and coats a cordierite honeycomb with a gamma-like alumina and metals and metal oxides containing Pt, Pd and TiO ₂ and then impregnates the nanometal colloidal particles Pt and Pd; The cordierite was coated with a gamma-shaped alumina, CuO, Cu (NO ₃ ) ₂ -3H ₂ O, a metal oxide containing indium acetate, and an organometal, and calcined to form a colloidal nanometal particles Cu, Ag, Au. A second step of fabricating a reduction catalyst filter to be impregnated; DOC / NOx catalyst and a discharge filter containing a nano-metal particles comprising a third step of combining a negative electrode plate forming a hole around the anode pin and a discharge filter forming a pair of the anode pin in the catalyst filter; Combined diesel vehicle exhaust purification system. The oxidation / reduction catalyst combining the first step and the second step, wherein Pt, Pd, TiO ₂ , CuO, Cu (NO ₃ ) ₂ -3H ₂ O, Metal oxides containing indium acetate and nano metal particles of organic metals and colloidal nano metal particles, characterized in that an oxidation / reduction coupling catalyst comprising Pt, Pd, TiO ₂ , Cu, Ag, Au and a discharge filter are combined Diesel car exhaust purification apparatus combined with a DOC / NOx catalyst and discharge filter included. According to claim 1, The catalyst material of the metal and metal oxide is a gamma-phase alumina and Pt, Pd, TiO ₂ of the metal, organometallic and metal oxide size of 2-20㎛ size, 5-20wt% content The nanometal colloidal particles are 5-15 nm in size and have a concentration of 1-5 mg / l. Device.

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