KR20030096889A - Catalyst for prevention of poison for automobile - Google Patents

Abstract

PURPOSE: A catalyst for prevention of poison for an automobile is provided to improve endurance activity by forming a catalytic converter with a plurality of catalytic system. CONSTITUTION: A ternary catalytic converter(10) comprises a diesel particulate filter catalyst(11) located at the introduction unit of emission and coated with a wash coat containing platinum, a palladium catalyst(12) having excellent light-off temperature function, and a palladium-rhodium mixed catalyst(13) located at the discharge unit of the emission and having excellent ternary activity.

Description

Catalyst for prevention of poisons in gasoline vehicles

The present invention relates to a catalyst for preventing poisonous substances in a gasoline vehicle, and more particularly, to configure a converter of a catalyst in a form in which a plurality of catalyst systems having different component configurations are arranged in a row, wherein the first catalyst system located at an exhaust gas introduction part is a precious metal. For example, a diesel particulate filter (DPF) catalyst coated with a wash coat carrying platinum (pt) is used, and a second catalyst system and a third catalyst system located at an exhaust gas outlet have excellent LOT (Light-Off Temperature) performance. It consists of a palladium (Pd) catalyst and a mixture of palladium (Pd) and rhodium (Rh) with excellent three-way activity, allowing all poisonous substances to react or be filtered on the DPF catalyst and the second and third catalysts By increasing the durability of the catalyst without being affected by the gas, the poisonous substances of the gasoline vehicle that can cope with the exhaust regulation It relates to a fat fat catalyst.

In general, as the utilization of automobiles increases, traffic congestion, damage caused by various traffic accidents and vibrations, and serious air pollution due to exhaust gases have emerged as serious and important social problems.

Gases emitted from automobiles are divided into exhaust gas, blow-by gas and evaporative gas.

Among the exhaust gas is a gas fuel is dedicated to act by expansion after the combustion in the cylinder as a gas at a high temperature and high pressure discharged into the atmosphere from an exhaust pipe, which accounts for most of the exhaust gas water vapor and carbon dioxide (CO ₂₎ And other harmful substances such as carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx).

Therefore, researches are being conducted to reduce the emission of these harmful components by decomposing the exhaust gas into catalysts, and these efforts have a considerable effect and are currently applied to various vehicles.

In the case of gasoline vehicles, as the exhaust regulations become more stringent, the durability of the catalyst is increasingly necessary. In the case of exhaust regulation, the vehicle is evaluated at a constant speed of the vehicle, and the exhaust gas, carbon monoxide (CO), hydrocarbon ( Evaluate the emission control by measuring the amount of HC) and NOx in g / mile.

Conventional catalyst systems have focused on improving the thermal stability of catalysts, and have focused on improving the thermal stability of catalysts.

In practice, however, the thermal stability of the catalyst has been improved, but despite the fact that the catalyst is endothelial toxic as important as the thermal stability, the catalyst by the poisonous substances (S, P, Zn, Ca, Pb, etc.) emitted from oil or fuel is There is no preventive measure against deterioration effect. In the past, when toxic substances were exposed on the catalyst, chemically endothelial toxic components were added to the catalyst to improve the endothelial toxicity of the catalyst. There is a difficult problem.

Accordingly, the present invention has been made in order to solve the above problems, a plurality of catalyst systems composed of different components constitute a converter in a form arranged in a line, the first catalyst system located in the exhaust gas inlet is a precious metal ( For example, the DPF (Diesel Particulate Filter) catalyst coated with a wash coat carrying platinum (pt), and the third catalyst system located in the exhaust and exhaust gas, respectively, have excellent LOT (Light-Off Temperature) performance. Pd) catalyst and palladium (Pd) and rhodium (Rh) mixed catalyst with excellent three-way activity, so that all poisonous substances react or filter on the DPF catalyst and the second and third catalysts are affected by the poisonous substance. By increasing the durability of the catalyst by preventing it from being received, a catalyst for preventing poisonous substances in a gasoline automobile that can cope with exhaust regulations can be eliminated. The purpose is to make things happen.

1 is a view showing a catalyst for preventing poisons in a gasoline vehicle according to the present invention

2 is a perspective view showing a DPF catalyst according to the present invention

Figure 3 is a perspective view showing the catalyst wall of the DPF catalyst according to the present invention

Figure 4 is a graph showing the oil poisoning effect for each catalyst volume and catalyst precious metal in FTP mode according to the present invention

5 is a graph showing hydrocarbon (HC) activity versus oil consumption according to the present invention.

6 is a view for comparing the purification effect on sulfur poisoning material according to the present invention

<Explanation of symbols for the main parts of the drawings>

10: catalytic converter 11: DPF catalyst

11a: catalyst wall 11b: straight flow path

11c: blocking membrane 12: palladium catalyst

13: palladium and rhodium mixed catalyst

Hereinafter, the features of the present invention for achieving the above object are as follows.

The present invention is a three-way catalytic converter for automobiles,

The converter 10 of the catalyst is configured in a form in which a plurality of catalyst systems having different components are arranged in a line, and the first catalyst system located at the exhaust gas introduction part is a DPF coated with a washcoat carrying precious metal (platinum (pt)). (Diesel Particulate Filter) catalyst (11), the second catalyst system and the third catalyst system located in the exhaust gas discharge portion is a palladium (Pd) catalyst (12) having excellent LOT (Light-Off Temperature) performance, respectively, palladium ( It is characterized by consisting of the Pd) and the rhodium (Rh) mixed catalyst (13).

Particularly, in the structure of the DPF catalyst 11, one of the grid-shaped linear flow paths 11b extending in the horizontal direction is closed by the blocking film 11c on the exhaust gas inlet side, and the other on the exhaust gas outlet side. Closed by the blocking film 11c, it is characterized in that one of the two adjacent straight flow paths 11b is provided with a catalyst wall 11a which is an inflow passage of the exhaust gas and the other is an outflow passage.

Due to the structure as described above, the exhaust gas inevitably passes through the catalyst wall 11a, and passes through the catalyst wall 11a to form a compound by an oxidation reaction and the like, and remain on the catalyst wall 11a. Exhaust gas trapped with poisonous substances reacts with the second and third catalysts 12 and 13 to purify harmful substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx), which are main components of the exhaust gas.

Hereinafter, the configuration of the present invention with reference to the accompanying drawings in detail.

The present invention relates to a catalyst for preventing poisonous substances in a gasoline vehicle, and as illustrated in FIG. 1, the converter 10 of the catalyst is configured in a form in which a plurality of catalyst systems having different component configurations are arranged in a row, and exhaust gas The first catalyst system located at the inlet is a diesel particulate filter (DPF) catalyst (11) coated with a washcoat carrying precious metal (e.g. platinum (Pt)), and the second catalyst system at the second and exhaust gas outlets, respectively. It is composed of a palladium (Pd) catalyst 12 having excellent LOT (Light-Off Temperature) performance and a mixed catalyst 13 of palladium (Pd) and rhodium (Rh) having excellent three-way activity.

Looking at the plurality of catalyst systems constituting the catalyst for preventing poisoning according to the present invention in detail.

First, the diesel particulate filter (DPF) catalyst 11 is used to filter a substance that adversely affects catalytic activity such as S, P, Zn, Ca, and Pb, which are poisonous substances contained in the exhaust gas. The constituent material of) is composed of a coating of a washcoat carrying a low content of platinum (pt) on top of the same coolite or SiC as a general catalyst support.

The DPF catalyst 11 containing noble metals and platinum chemically reacts with oil and fuel components contained in the exhaust gas to form oxides or other compound forms on the catalyst.

By doing so, the second and third catalysts located behind the DPF catalyst 11 can fundamentally prevent deactivation due to poisoning substances or the like.

As shown in FIGS. 2 and 3, the structure of the DPF catalyst 11 is provided with a linear flow path 11b having a lattice pattern in cross section, and is provided in the linear flow path 11b extending in a plurality of horizontal directions. In this case, one side is closed by the blocking film 11c on the exhaust gas inlet part side, and the other is closed by the blocking film 11c on the exhaust gas outlet part side.

In this way, one of the two adjacent horizontal spaces becomes an inflow passage of the exhaust gas, the other becomes an outflow passage, and the exhaust gas forms the catalyst wall 11a as indicated by the arrow in FIG. It is meant to pass.

Due to the structure as described above, the exhaust gas inevitably passes through the catalyst wall 11a, undergoes an instant oxidation reaction, etc. when passing through the catalyst wall 11a, and forms a compound to remain on the catalyst wall 11a. Exhaust gas on which the poisonous substance is caught reacts with the second and third catalysts 12 and 13 to purify harmful substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) which are main components of the exhaust gas.

The cell density / cell thickness used for the general catalyst is 400 / 6.5, but the purpose of the DPF catalyst 11 is not the purification but the purpose of filtering, so it is not necessary to increase the cell density.

Therefore, the cell density is low density, that is, about 100 to 200 CPSI.

The reason why the low-density platinum catalyst is coated on the DPF catalyst 11 is to show an oil poisoning effect for each catalyst noble metal in the FTP mode as shown in the graph shown in FIG. 4, and the platinum catalyst appears to be resistant to poisoning.

The other second catalyst uses a palladium catalyst 12 having excellent LOT performance, and the third catalyst uses a palladium and rhodium mixed catalyst 13 having excellent three-way activity.

Conventional catalyst deterioration mechanisms have been recognized that catalysts are deteriorated as the catalysts are thermally damaged and the precious metals supported on the catalysts are sintered at high temperatures to cause grain growth, thereby losing the active surface area.

However, as the exhaust regulations are gradually tightened, the amount of the precious metal supported on the catalyst is fundamentally increased, and even though it is thermally affected, it is recognized that a large amount of precious metal is supported so that the thermal activity is not largely lost.

On the contrary, the oil or fuel component contained in the engine exhaust gas forms compounds on the surface of the precious metal, which poses a further problem in that the precious metal exhibits activity. The hydrocarbon (HC) activity versus the oil consumption of FIG. This can be seen from the graph representing.

In general, the characteristics of the catalyst are also important in the initial activity, but the durability is important as the initial activity is aged (aging).

Therefore, the catalyst exhaust regulation is to evaluate the catalyst of a vehicle that has traveled 50K miles and 150K miles.

At this time, the catalyst will also be thermally affected, but in recent years tends to be more inactive under the influence of the poisoning material, focusing on the advantages to improve the effect of inertness by the poisoning material of the catalyst.

Therefore, all poisonous substances are reacted or filtered on the DPF catalyst 11 so that the poisonous substances are not affected by the palladium catalyst 12 as the second catalyst and the palladium and rhodium mixed catalyst 13 as the third catalyst. By increasing the endurance activity, it is possible to cope with exhaust regulation.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example

In order to evaluate the catalytic converter of the present invention, as shown in FIG. 6, the effects on sulfur (S) poisoning substances were examined.

The test conditions were continued for 100 hours by supplying air in an oxygen atmosphere containing 100 ppm sulfur at 900 ℃.

After the above treatment, activity evaluation was performed.

The following Table 1 summarizes the activity according to temperature in the position of LOT (Light-Off Temperature) with the air volume / fuel quantity perturbated at a period of ± 0.5 and 1Hz at 14.6.

T15, T50, and T75 represent the temperatures when the purification rates are 15%, 50%, and 75%.

W / DPF and W / O DPF are shown with and without DPF.

In Table 1, in the case of W / DPF, the effect of the poisoning material is small, and shows similar activity to that of the initial state. However, in the case of W / O DPF, the LOT of carbon monoxide (CO) and hydrocarbon (HC) is about 50. It was found that the increase was more than ℃, and in the case of NOx, the purification rate did not increase by more than 75%.

Accordingly, it can be seen that by installing the DPF (Diesel Particulate Filter) catalyst 11 in a thin thickness at the exhaust gas introduction portion of the catalytic converter 10, the effect on the poisoning substance can be reduced, thereby increasing the durability of the catalyst in the long term. have.

As described above, the catalyst for preventing poisonous substances of a gasoline vehicle according to the present invention causes all poisonous substances to react or is filtered on the DPF catalyst so that the second catalyst, the palladium catalyst and the third catalyst, the palladium and rhodium mixed catalyst are poisonous substances. By increasing the durable activity of the catalyst so as not to be affected by the, there is an effect that can cope with the exhaust regulation.

Claims (2)

In the automotive three-way catalytic converter, The converter 10 of the catalyst is configured in a form in which a plurality of catalyst systems having different components are arranged in a line, and the first catalyst system located at the exhaust gas introduction part is a DPF coated with a washcoat carrying precious metal (platinum (pt)). (Diesel Particulate Filter) catalyst (11), the second catalyst system and the third catalyst system located in the exhaust gas discharge portion is a palladium (Pd) catalyst (12) having excellent LOT (Light-Off Temperature) performance, respectively, palladium ( Pd) and rhodium (Rh) mixed catalyst 13, characterized in that the catalyst for preventing poisons in a gasoline vehicle. 2. The structure of the DPF catalyst 11 according to claim 1, wherein one side of the linear flow path 11b having a lattice pattern extending in the horizontal direction is closed by the blocking film 11c at the exhaust gas inlet side, and the other is exhausted. It is closed by the blocking film 11c at the gas discharge side, and one of two adjacent straight flow paths 11b is provided with a catalyst wall 11a which is an inflow passage of the exhaust gas, and the other is an outflow passage. Catalyst for preventing poisonous substances in gasoline cars.