JP2002256859A - Catalyst converter for stationary gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst converter capable of preventing the drift of an exhaust gas, improving a catalyst function and making compact as a whole. SOLUTION: The catalyst converter (100) is provided with a housing (10) having a cone part (13) expanded in diameter toward the downstream side of the inflow port (14) in which an exhaust gas flows, and a catalyst bed (20) which is installed at the downstream side of the cone part and carries a catalyst component for controlling exhaust emission. The converter is further provided with a filter (40) forming a gas passage (16) which is set on the center of cone part cross section opposed to the inflow port and passes the exhaust gas through a space between the filter and the inner peripheral face of the cone part. Since the filter is disposed inside the cone part, the capture of poisoning substances and the dispersion of exhaust gas can be attained in combination.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic converter for a stationary gas engine for purifying exhaust gas from a stationary gas engine or the like (hereinafter referred to as "catalytic converter" as appropriate).

[0002]

2. Description of the Related Art In recent years, environmental problems have become serious on a global scale.
Air pollution gas emission regulations are strictly enforced,
Not limited to cars, motorcycles, etc., companies, hotels, hospitals, large stores
Cogeneration system that supplies electric power and thermal energy to pavement
Exhaust gas from stationary gas engines used as station equipment
Emission regulations for gases are becoming stricter.
You. Air pollutant gases include carbon monoxide (CO) and hydrocarbons
(HC), nitrogen oxides (NO _x), Sulfur oxides (SO_x)
Exhaust gas containing these is used as an oxidation catalyst, reduction catalyst, etc.
It is often purified using a medium, a three-way catalyst or the like. Soshi
When purifying exhaust gas using a catalyst,
The barter must function effectively. For example, Japanese Unexamined Patent Publication
JP-A-86843 discloses that the function of a catalytic converter is controlled by temperature.
Pre-catalyst is installed upstream from the surface to secure
To increase the temperature of exhaust gas reaching the main catalyst.
An exhaust gas purifying apparatus for a motorcycle is disclosed.

[0003]

However, in the motorcycle exhaust gas purifying apparatus disclosed in that publication, only the temperature rise of exhaust gas reaching the main catalyst is a problem. In order for the catalytic converter to function effectively, it is also necessary to suppress or prevent the gas flow drift inside the catalytic converter and the deterioration of the catalyst (component) due to the poisoning substance. For example, in the case of a catalytic converter for a stationary gas engine as shown in FIG. 5, the exhaust gas flowing from the inlet flows abruptly from the center to the inner peripheral wall inside the catalytic converter as indicated by the arrow in FIG. (Or flow)
Decrease. Therefore, the flow of the exhaust gas inside the catalytic converter has a very uneven drift. As a result, the entire catalyst bed on which the catalyst components are supported is not effectively used, and exhaust gas is not sufficiently purified, or the catalyst bed is enlarged in order to secure purification of exhaust gas. It also hinders downsizing.

[0004] Therefore, as shown in FIG.
For dispersing exhaust gas in a dispersive manner ahead of
It is conceivable to provide a filter 220 for trapping a poisoning substance such as sulfide in front of the catalyst bed in order to prevent the catalyst bed 230 from being poisoned.
However, in the catalytic converter 200 of FIG. 6, even if the flow of the exhaust gas is made uniform by the dispersing cone 210,
Therefore, it is necessary to provide a filter so as to cover the entire surface of the catalyst bed 230. As a result, in the catalytic converter 200, new problems such as an increase in the size in the axial direction, an increase in the weight of the catalytic converter, a need to reinforce the structure of the filter, an increase in cost, and an increase in pressure loss of exhaust gas are caused.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a catalytic converter capable of ensuring the function of a catalyst bed and reducing the overall weight and size. .

[0006]

Means for Solving the Problems Accordingly, the present inventors have:
In order to solve this problem, intensive studies have been carried out, and as a result of trial and error, the inventors of the present invention have conceived to provide a filter for a poisoning substance which also serves to prevent drifting of exhaust gas at a position facing the inlet of exhaust gas. Has been developed. That is, the catalytic converter of the present invention comprises a housing having an inflow port into which exhaust gas flows, a cone portion having a diameter increasing downstream downstream from the inflow port, and purifying the exhaust gas provided downstream of the cone portion. And a catalyst bed on which a catalyst component is carried, wherein the exhaust gas flows between the inner peripheral surface of the cone portion, which is disposed at the center of the cross section of the cone portion and faces the inlet. It is characterized by comprising a filter forming a gas passage.

[0007] Since a filter is disposed at the center of the cross section of the cone portion where the exhaust gas flow rate is large, facing the inflow port, almost all of the inflowed exhaust gas once falls on the filter, and is included in the exhaust gas. Poisons are efficiently captured by the filter. However, the exhaust gas after the removal of the poisonous substance has the following two flows. That is, many of the exhaust gas from which the poisoning substances have been removed passes directly through the filter, and the rectifying action of the filter suppresses the drift and is guided to the catalyst bed almost uniformly. On the other hand, among exhaust gases from which poisonous substances have been removed, those that do not directly pass through the filter may also be exhaust gas formed between the inner peripheral surface of the cone portion and the filter (that is, on the outer peripheral portion of the filter). After passing through the passage, the exhaust gas is guided to the outer peripheral portion of the catalyst bed, and the exhaust gas is also guided to a portion of the catalyst bed that has hardly flowed in the past.

As described above, according to the catalytic converter of the present invention, the filter has both the removal of poisoning substances and the suppression and prevention of the drift of exhaust gas. It is used for As a result, efficient exhaust gas purification is performed stably for a long period of time. In addition, by disposing a filter at the center of the cross section of the cone part where the exhaust gas flow rate is large, facing the inflow port, there is no need to cover the entire catalyst bed with a filter. Can be achieved. Further, by reducing the size of the filter, the pressure loss of exhaust gas can be reduced, and a decrease in engine performance can be prevented.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the catalytic converter according to the present invention will be described. (1) Size and Arrangement Position of Filter At the upstream end position of the filter, the ratio of the upstream end area of the filter to the cross-sectional area of the cone portion in the direction perpendicular to the axial direction is 0.25 to 0.6. Preferably, the ratio of the length from the upstream end of the cone to the upstream end of the filter to the axial length of the cone is 0.1 to 0.5. At the upstream end position of the filter, the ratio of the area of the upstream end of the filter to the cross-sectional area of the cone portion in the direction perpendicular to the axial direction is set to 0.25 to 0.6 because the flow rate from the inlet to the catalytic converter is increased. As a result of analyzing the flow of the exhaust gas, the filter was poisoned when the filter had an upstream end area of 0.25 to 0.6 with respect to the cross-sectional area of the cone in the direction perpendicular to the axial direction. This is because it has been found that it is preferable for capturing the substance and preventing drifting. The area ratio is 0.
If it is less than 25, the cross-sectional area of the filter portion is too small, the amount of exhaust gas coming into contact with the filter is reduced, and the effect of trapping poisonous substances becomes insufficient, and the effect of dispersing the flow becomes insufficient. On the other hand, if the area ratio exceeds 0.6,
This is not preferable because the influence of the increase in pressure loss increases and the size of the filter increases.

It is preferable that a ratio of a length from an upstream end of the cone portion to an upstream end of the filter to an axial length of the cone portion is 0.1 to 0.5. Similarly, as a result of analyzing the flow of exhaust gas flowing into the catalytic converter from the inlet, the axial length of the cone (total length of the cone)
On the other hand, if the filter is disposed at a position where the ratio of the length (distance) from the upstream end of the cone portion to the upstream end of the filter is 0.1 to 0.5, the poisoning substance can be trapped. It has been found that this is preferable for preventing drifting. The ratio is 0.1
If it is less than 10, it becomes difficult to disperse the exhaust gas appropriately and flow, and also the maintainability described later deteriorates. Further, when the ratio exceeds 0.5, the filter approaches the catalyst bed, and similarly, it becomes difficult to appropriately disperse and flow the exhaust gas, and the filter also becomes large,
The effect of the present invention is reduced.

(2) Attaching and detaching of the filter It is preferable that the filter is fixed to the cone portion by a detachable fixing tool. If the catalytic converter is used for a long time, poisonous substances accumulate on the filter,
The trap performance of the filter may decrease. Therefore, if the filter is fixed to the cone portion by a detachable fixing tool, the filter can be appropriately replaced, and the performance of the catalytic converter can be maintained. Specifically, for example, a stay projecting from the filter may be fixed to a stay projecting from the inner peripheral surface of the cone portion using a bolt and a nut (fixing tool). In particular, it is preferable that the cone portion includes a sealable maintenance port for performing insertion / removal of the filter and attachment / detachment of the filter. This is because the use of the maintenance port allows the filter to be detached or replaced without disassembling or destroying the catalytic converter.

[0012] The "sealed type" means that when the filter is not replaced, the maintenance port is airtightly closed by a closed lid or the like so that leakage of exhaust gas from the catalytic converter can be prevented. Means Alternatively, instead of providing a maintenance port in the cone portion, the catalytic converter housing itself may be of an exploded type. For example, the catalytic converter is constituted by an upstream cone section connected to the inlet pipe and containing the filter, a downstream cone section connected to the outlet pipe, and a catalyst bed disposed therebetween, With bolts and nuts,
Disassembly and assembly may be performed as appropriate.

(3) Use of Catalytic Converter The catalytic converter of the present invention is preferably used for purifying exhaust gas of a stationary gas engine. Further, it is preferable that the catalytic converter of the present invention is used for a stationary gas engine for cogeneration. Recently, stationary gas engines that have excellent thermal efficiency and make effective use of heat have been used for power generation equipment, cooling / heating equipment, hot water supply equipment, or cogeneration energy equipment that combines them. Such equipment is also used in hotels, large stores, factories, hospitals, and the like, for example. In order to reduce the installation space, equipment that is as compact as possible is desired, and the catalytic converter of a stationary gas engine used in such equipment is, of course,
Compactness is required.

In particular, when the axial length is required to be reduced, in order to achieve both the reduction and the exhaust gas purification, the length of the inlet pipe (inlet) is about 5 to 10 times as shown in FIG. A catalytic converter with a catalyst bed having a cross-sectional area is used. However, in the conventional catalytic converter, as described above, the exhaust gas has drifted, and the entire catalyst bed has not always been used effectively. Therefore, when the catalytic converter of the present invention is used for purifying exhaust gas of a stationary gas engine, it is possible to reduce the size of the filter, shorten the axial direction of the catalytic converter, etc., and to further compact various facilities using the stationary gas engine. It becomes possible.

(4) Others The filter may be in a honeycomb shape or a pellet shape.
In order to suppress the pressure loss of the exhaust gas, if it is a honeycomb shape,
It is suitable. The honeycomb filter may be made of ceramics or metal (for example, a thin plate wound). The same applies to the catalyst bed, which may be in the form of a honeycomb or a pellet, and may be made of ceramics or metal.
Further, the cross-sectional shapes of the filter, the cone portion, and the catalyst bed may be circular or square (for example, rectangular).

The catalyst component supported on the catalyst bed may be appropriately selected according to the pollutant gas to be purified.
Platinum (Pt), rhodium (Rh), palladium (Pd)
Precious metals such as alkali metals, alkaline earth metals and NO _x storage material selected from rare earth elements, ceria (ceria -
Oxygen storage / release material such as zirconia composite oxide). The catalyst supporting layer for supporting the catalyst component includes activated alumina, silica, zirconia, titania, silica-
Materials such as alumina, zeolite, ceria, and ceria-zirconia can be used. In addition, it is preferable to use activated alumina, silica, zeolite, titania, or the like as the component to be carried on the filter, in order to secure the capturing ability.

[0017]

The present invention will be described in more detail with reference to the following examples. FIG. 1 shows a catalytic converter 100 according to one embodiment of the present invention. The catalytic converter 100 includes an upstream housing 10 (housing according to the present invention), a catalyst bed 20, and a downstream housing 30. And the upstream housing 10 and the catalyst bed 20
Flange 1 extending in the circumferential direction at their joint
The catalyst bed 20 and the downstream housing 30 are connected to each other by bolts and nuts 90 via the first and the first 21 so that the flanges 24 and 31 extending in the outer peripheral direction at their joints.
And a bolt / nut 90.
By the way, the downstream housing 30 includes a cone portion 33 having a diameter reduced from an opening end face having a flange 31,
Outlet 34 connected to the downstream side of outlet 3 and outlet 3
And a flange 32 provided on an end face of the muffler 4, and the flange 32 is connected to an outlet pipe leading to the muffler.

The catalyst bed 20 comprises a cylindrical honeycomb catalyst 22 provided in two rows in parallel, a cylindrical housing 23 for accommodating the honeycomb catalyst 22, and flanges 21 and 24 provided on both end surfaces. The honeycomb catalyst 22 is made of heat-resistant ferritic steel, and Pt and Rh (catalyst components) are supported on activated alumina (supporting layer). The upstream housing 10 includes a flange 12 connected to the inlet pipe,
A cylindrical inlet 14 connected to the flange 12;
4 and the catalyst bed 2 with the diameter increased from the downstream end face of the catalyst bed 2
0 is provided with a flange 11 which is connected to the flange. Furthermore, the upstream housing 10 faces the inflow port 14 and
Cylindrical cylindrical honeycomb filter 40 in the center of the cross section
(The filter according to the present invention) is provided therein, and the honeycomb filter 40 is detachably connected to the honeycomb filter 40 by bolts and nuts 90 by a stay 19 extending inward from the cone portion 13 and a stay 49 extending from the outer periphery of the honeycomb filter 40.
It is fixed in place.

The positional relationship between the cone portion 13 and the honeycomb filter 40 viewed from the inflow side end face of the honeycomb filter 40 is shown in FIG. As can be seen from FIG. 2, a gas passage 16 is formed between the cone portion 13 and the honeycomb filter 40. Further, the cone portion 13 of the upstream housing 10 includes a maintenance port 15 on the downstream side of the stay 19. Maintenance port 15
Can take the honeycomb filter 40 in and out,
The size is such that the bolt / nut 99 can be loosened and fastened. The maintenance port 15 can be sealed by fixing a lid (not shown) to the flange 15a of the maintenance port 15 with bolts and nuts.

Next, the specifications of the upstream housing 10, the catalyst bed 20, and the honeycomb filter 40 of this embodiment will be described in detail. The length of the cone portion 13 and the distance to the upstream end position of the honeycomb filter 40 were set as the axial length from the upstream end of the cone portion shown in FIG. 3 as follows. Length of cone part A: 360 mm Distance to upstream end position of honeycomb filter B: 120 mm Ratio of both (B / A): 0.33

The cross-sectional area of the cone portion 13 in the direction perpendicular to the axial direction and the ratio of the area of the upstream end of the honeycomb filter 40 at the upstream end position of the honeycomb filter 40 are set as follows with reference to FIG. did. Sectional area of cone part S1: 1850 mm ² Upstream end area of honeycomb filter S2: 700 mm ² Ratio of both (S2 / S1): 0.38 The specifications of the honeycomb filter 40 were set as follows. Carrier material: heat-resistant ferritic steel Supported component: activated alumina Number of cells: 31 cells / cm ^{2 The} poisoning substances captured by the honeycomb filter 40 include P, Pb, Si, Zn, Ca, C, S, S
n, halogen, organometallic compounds and the like.

The specifications of the catalyst bed 20 were set as follows. Structure: honeycomb Catalyst inflow area: 5100 cm ² Carrier material: heat-resistant ferritic steel Catalyst component: noble metal (Pt, Rh) Number of cells: 31 cells / cm ^{2 The specifications of the} cone portion 13 and the honeycomb filter 40 are set as described above. The state of the flow of the exhaust gas at the time of performing is shown by arrows in FIG. As can be seen from FIG. 4, according to the catalytic converter 100 of the present embodiment, after the exhaust gas hits the honeycomb filter 40 and the poisonous substances contained therein are trapped, the exhaust gas is discharged to the upstream housing 10. It flows almost uniformly through the inside, and reaches the catalyst bed 20 → the downstream housing 30.
In the present embodiment, since the honeycomb filter 40 is provided in the cone portion 13, the catalytic converter 100 does not extend in the axial direction, and the honeycomb filter 4
0 itself is compact, so the catalytic converter 100
Becomes lighter. Further, if the maintenance port 15 is used, the honeycomb filter 40 can be easily replaced.

[0023]

According to the catalytic converter of the present invention, the drift of the exhaust gas is suppressed and prevented, so that the function of the catalyst bed is secured and the size of the filter for trapping the poisoning substance can be reduced. Therefore, the catalytic converter itself can be made compact.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a catalytic converter of the present invention.

FIG. 2 is a sectional view taken along line CC of the embodiment shown in FIG.

FIG. 3 is an explanatory diagram for explaining specifications of the embodiment shown in FIG. 1;

FIG. 4 is a diagram showing a flow of exhaust gas of the embodiment shown in FIG. 1;

FIG. 5 is a diagram showing a flow of exhaust gas when a dispersion cone is not provided in a catalytic converter.

FIG. 6 is a view showing a catalytic converter provided with a dispersion cone.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Catalytic converter 10 Upstream housing (housing) 13 Cone section 14 Inlet 16 Gas passage 20 Catalyst bed 30 Downstream housing 40 Honeycomb filter (filter)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // B01D 46/00 B01D 53/36 103Z F-term (reference) 3G090 AA01 AA02 EA02 EA03 3G091 AA06 AA19 AB13 BA11 BA14 BA15 BA19 BA39 CA27 GA01 GA06 GB01X GB01Z GB02Y GB03Y GB04Y GB05W GB06W GB07W GB10X GB16X GB17X HA16 HA18 HA47 4D048 AA01 AA06 AA11 AA13 AA14 AA15 AA16 AA18 AB01 AB02 BA30X BA39X BB02 BC01 K02 Q03 Q03 Q01 K02

Claims (5)

[Claims] 1. A housing having an inlet into which exhaust gas flows, a cone extending downstream from the inlet, and a catalyst component provided downstream of the cone to purify exhaust gas. And a supported catalyst bed, wherein the exhaust gas flows between the inner peripheral surface of the cone portion, which is disposed at the center of the cross section of the cone portion and faces the inlet. 1. A catalytic converter for a stationary gas engine, comprising: a filter forming a gas passage. 2. A ratio of an area of an upstream end of the filter to a cross-sectional area of the cone in a direction perpendicular to an axial direction at an upstream end of the filter is 0.25 to 0.6. The ratio of the length from the upstream end of the cone portion to the upstream end of the filter to the axial length is 0.1 to 0.5.
5. The catalytic converter for a stationary gas engine according to claim 1, wherein 3. The catalytic converter for a stationary gas engine according to claim 1, wherein said filter is fixed to said cone portion by a detachable fixing tool. 4. The catalytic converter for a stationary gas engine according to claim 3, wherein said cone portion is provided with a sealable maintenance port for inserting and removing said filter and for attaching and detaching said filter. 5. The catalytic converter for a stationary gas engine according to claim 1, which is used for purifying exhaust gas of a stationary gas engine.