JP2001276573A - Exhaust gas cleaning catalyst apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust gas cleaning catalyst apparatus wherein an exhaust gas passage and a reaction gas passage are so constituted that the wall surface of a catalyst carrier is held between both passages and a catalyst for reacting reaction gas with exhaust gas to clean the exhaust gas is simply constituted as exhaust gas and reaction gas introducing passages to lower pressure loss. SOLUTION: Exhaust gas passages and reaction gas passages are alternately laminated as layers (2S, 3S) divided into a plurality of parallel small passages (2, 4) and arranged so that the flow directions of the passages (2, 4) of exhaust gas (E) and reaction gas (R) cross each other to constitute a catalyst carrier (3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying exhaust gas with one side sandwiching the wall surface of a permeable catalyst carrier and the other side as a reaction gas passage for reacting with the exhaust gas. The present invention relates to a catalyst device for purifying exhaust gas.

[0002]

2. Description of the Related Art Conventionally, as a technique for directly dispersing and adding a reducing agent to exhaust gas of a diesel engine to reduce and purify NOx, for example, JP-A-6-137136 and JP-A-9-13956 are disclosed. It has been disclosed. However, in such a method in which the reducing agent is directly dispersed and added to the exhaust gas, combustion or diffusion of oxygen in the exhaust gas occurs before the reducing agent reaches the catalytic reaction site, and the reducing agent concentration in the catalytic reaction site is increased. Decrease.

On the other hand, in an exhaust gas purifying catalyst, one of the exhaust gas purifying catalysts has an exhaust gas passage sandwiching a wall of a permeable catalyst carrier.
The opposite side is a reaction gas passage, and when forming a catalyst for purifying exhaust gas by reacting the reaction gas with the exhaust gas, the exhaust gas passage and the reaction gas passage are formed by a conventionally used honeycomb type catalyst carrier structure. The exhaust gas and the reactant gas are parallel to these passages, and the introduction passages for introducing the gas into these passages may intersect and interfere with each other, resulting in a complicated structure and a large pressure loss.

[0004]

SUMMARY OF THE INVENTION The present invention addresses the above-mentioned problems and provides an exhaust gas purifying catalyst apparatus having a catalyst carrier wall sandwiching one side of the exhaust gas passage opposite to a reaction gas passage. It is another object of the present invention to propose a technique in which a reaction gas introduction passage can be easily configured and pressure loss can be reduced.

[0005]

According to the present invention, one side of a wall of a permeable catalyst carrier is formed as a passage for an exhaust gas to be purified and the other side is formed as a passage for a reaction gas to be reacted with the exhaust gas. In the exhaust gas purifying catalyst device that purifies the exhaust gas, the exhaust gas passage and the reactant gas passage are each constituted by a plurality of parallel passages, and the exhaust gas passage and the reactant gas passage intersect. To form a catalyst carrier.

A plurality of exhaust gas passages and a plurality of reaction gas passages are arranged to provide a plurality of exhaust gas layers and a plurality of reaction gas layers, respectively, and the exhaust gas layers and the reaction gas layers are alternately laminated. Thus, the catalyst carrier is constituted.

Therefore, according to the present invention, since the passage of the exhaust gas and the passage of the reactant gas are formed so as to intersect with each other, the inlets of the respective passages are separated from each other, the introduction passages can be simply constructed, and the pressure is reduced. We can do something with low loss.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a box-shaped catalyst case 1
, A catalyst carrier 3 described later is inserted therein. An exhaust inlet 1A is provided on one surface thereof, and exhaust gas E from the engine is introduced, and is configured to be discharged from an opposite exhaust outlet 1B through an exhaust gas passage of the catalyst carrier 3. Further, a reaction gas inlet 1C is provided in a direction orthogonal to the flow of the exhaust gas E.

As shown in FIG. 2, the catalyst carrier 3 has a plurality of exhaust gas layers 2S through which the exhaust gas E flows and a plurality of reaction gas layers 4S through which the reaction gas R flows orthogonally to the flow (in the example shown in FIG. 2). (Two layers each)
Although not shown in FIG. 2, each of the layers 2S and 4S is divided into a plurality of passages 2 and 4, respectively.

[0010] The wall surface of the catalyst carrier 3 where the exhaust gas passage 2 and the reaction gas passage 4 are in contact with the front and back surfaces has a property of transmitting the reaction gas R. Silicon or cordierite is used.

FIG. 3 shows a case in which the reaction gas R is a nitrogen oxide (hereinafter referred to as NOx) reduction catalyst as a reducing agent, and a NOx catalyst supporting layer 3a is provided on the surface of the catalyst carrier 3 in contact with the exhaust gas E. On the surface formed and in contact with the reducing agent (R), a reducing agent reforming catalyst supporting layer 3b is formed. The reducing agent (R) in the reaction gas passage 4 is reformed in the reducing agent reforming catalyst supporting layer 3b, passes through the catalyst carrier 3 in the direction of arrow X, and
The exhaust gas E is reduced by the NOx catalyst carrying layer 3a on the side to purify NOx.

In the example shown in FIG. 4, the exhaust gas layer 2S and the reaction gas layer 4S are each partitioned into a plurality of exhaust gas passages 2 and reaction gas passages 4 by a heat resistant stainless steel corrugated sheet P1, and a micro-perforated heat resistant stainless steel flat plate is provided between each layer. The catalyst carrier 3A is formed by welding using P2. In the illustrated example, the exhaust gas passage 2 and the reaction gas passage 4 are shown to flow orthogonally on the projection, but the intersection angle on the projection is not limited to 90 degrees and may be appropriately selected.

FIGS. 5 and 6 show examples of catalyst carriers formed by molding with silicon carbide or cordierite or the like. As shown in FIG. 5, in the exhaust gas layer 2S and the reaction gas layer 4S, a plurality of upwardly open passages 2 and 4, which are respectively provided in parallel, are formed. As shown in FIG. 6, the catalyst carrier 3B is formed by alternately overlapping the exhaust gas layers 2S and the reaction gas layers 4S in different directions. Also in this case, the intersection angle is not limited to 90 degrees and can be selected.

[0014]

The present invention is constructed as described above, and the catalyst carrier is formed such that the exhaust gas passage and the reaction gas passage intersect in the flow direction, and their inlets are mutually connected. Since they are arranged at a distance, the introduction passage can be simply configured, and one with low pressure loss can be configured. Therefore, a catalyst for purifying the exhaust gas by reacting the exhaust gas with the reaction gas across the catalyst carrier wall surface, for example, a NOx reduction catalyst or the like can be provided at high performance with low pressure loss and at low cost.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view illustrating the catalyst carrier of FIG.

FIG. 3 is a cross-sectional view illustrating a wall surface of a catalyst carrier.

FIG. 4 is a perspective view showing one embodiment of a catalyst carrier.

FIG. 5 is a perspective view showing another embodiment of the exhaust gas layer and the reaction gas layer.

FIG. 6 is a perspective view showing a catalyst carrier composed of the exhaust gas layer and the reaction gas layer of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Catalyst case 1A ... Exhaust gas input 1B ... Exhaust gas outlet 1C ... Reaction gas inlet 2 ... Exhaust gas passage 2S ... Exhaust gas layer 3 ... Catalyst carrier 4 ...・ Reaction gas passage 4S ・ ・ ・ Reaction gas layer

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (2)

[Claims] 1. An exhaust gas purifying catalyst device for purifying exhaust gas, wherein one side of a wall of a permeable catalyst carrier is sandwiched between the path of exhaust gas to be purified and the other side is a path of reaction gas for reacting with the exhaust gas. Wherein the exhaust gas passage and the reaction gas passage are each constituted by a plurality of parallel passages,
An exhaust gas purifying catalyst device characterized in that the exhaust gas passage and the reaction gas passage are arranged so as to cross each other to constitute a catalyst carrier. 2. A plurality of exhaust gas layers and a plurality of reaction gas layers each having a plurality of the exhaust gas passages and a plurality of reaction gas passages arranged therein, and the exhaust gas layers and the reaction gas layers are alternately arranged. The exhaust gas purifying catalyst device according to claim 1, wherein the catalyst carrier is formed by stacking.