WO2019128561A1

WO2019128561A1 - Honeycomb ceramic hole-plugging structure

Info

Publication number: WO2019128561A1
Application number: PCT/CN2018/116704
Authority: WO
Inventors: 宋锡滨; 张兵; 张曦
Original assignee: 山东国瓷功能材料股份有限公司
Priority date: 2017-12-27
Filing date: 2018-11-21
Publication date: 2019-07-04
Also published as: CN109356688A; CN108278142A

Abstract

A honeycomb ceramic hole-plugging structure, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface, wherein the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface comprise first area grids (1) having S ≤ 25% and second area grids (2) having S > 25% at the skin edge, all of the first area grids (1) being plugged at the inlet surface and/or the outlet surface; wherein S is a proportion of incomplete-grid surface area to complete-grid surface area in a certain grid. The honeycomb ceramic hole-plugging structure selectively plugs small incomplete grids so as to meet discharge requirements and has the advantages of small back pressure, good thermal shock resistance, low production cost and a good filtering effect.

Description

Honeycomb ceramic plugging structure

Technical field

The present invention relates to the field of honeycomb ceramic filters, and more particularly to a honeycomb ceramic plugging structure.

Background technique

Honeycomb ceramic wall flow filters remove carbon black from gasoline and diesel exhaust. The traditional filter design has an inlet and an outlet, as well as a porous wall that separates the inlet and outlet. These interconnected walls divide the filter into an inlet channel and an outlet channel. To capture carbon black and ash, the outlet end of the inlet channel is blocked and the inlet of the outlet channel is blocked. The structure in which such an interval is blocked is like a chess board. This design forces the exhaust gas to pass through the porous wall, allowing the particulate matter to deposit in the channel or wall. Typically, the inlet and outlet channels have a square cross section of the same area. When the amount of carbon black reaches a certain level, the regeneration process takes place and the carbon black is burned off.

In the production of honeycomb ceramic filters, the structure of the honeycomb is completed by extrusion molding. During this process, the interconnected walls form the honeycomb ceramic structure with the outermost wall (also known as the skin). The lattice channels formed by most of the interconnected walls are completely square. However, some lattices formed by walls and skin are irregular structures, and these lattices are called incomplete lattices. In theory, these incomplete grids can be based on the usual checkerboard caulking method. In practice, however, it is very difficult to achieve a high quality plugging process for incomplete grids formed by extruded skin and joined walls. Some problems are caused by the extrusion quality of the filter, some are caused by the laser drilling process, and so on. Therefore, it is necessary to manually detect and manually block the missing lattice after plugging. These problems must be solved because of the environmental requirements of the number of particles (PN).

The number of incomplete lattices near the skin (N _p ) can be estimated by the following formula:

N _p =πN _d (1)

Where π is the pi, and N _d is the total number of plaids on the diameter line. From this formula (1), it can be seen that the incomplete grid has a large number, so it cannot be ignored, especially to meet the PN emission regulations and back pressure considerations.

Although there are very common processes to block the complete grid, it is not a simple matter to block the incomplete grid. For large-size filters, the usual process is to grind the outer skin and then put the skin material on it (called the skin grafting process). In the process of skin grafting, the incomplete grid is automatically filled by the skin material. For small size filters, the skin is formed during the extrusion process and there must be a way to block these incomplete grids.

One way of dealing with incomplete lattices in the prior art is that the blocking of the incomplete grid is the same as the normal complete grid. In production, some grids are found to be unblocked or blocked incorrectly. There are many reasons for these problems, some due to the quality of the extrusion and some based on the punching process. Therefore, it takes more time to correct these incomplete grid blocking problems.

One way of dealing with incomplete grids in the prior art is that the incomplete grid is blocked by the extruded material, just like the extruded wall. This method can have a high filtration effect to meet the particle weight (PM) emission requirements. However, as more material is squeezed into this small area, the structural modulus increases, resulting in a problem of insufficient thermal shock resistance during regeneration.

One way of dealing with incomplete grids in the prior art: all incomplete grids are not blocked. Although this solution can meet some of the previous emission requirements, it is not advisable for new emission requirements, such as the number of particles (PN).

Therefore, there is a way to block the incomplete grid, and this method does not have a negative impact on PN emissions, back pressure and thermal stress.

Summary of the invention

(1) Technical problems to be solved

The object of the present invention is to provide a honeycomb ceramic plugging structure, which solves the problems in the prior art that the non-conforming emission requirements, the back pressure increase, and the thermal shock resistance are poor due to untreated or excessively processed incomplete lattices.

(2) Technical plan

In order to solve the above technical problem, the present invention provides a honeycomb ceramic plugging structure, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface, the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface including at the edge of the skin a first area lattice of S≤25% and a second area lattice of S>25%, all of the first area lattices are blocked at the inlet surface and/or the exit surface; wherein S is an incomplete lattice of a certain lattice The area accounts for the proportion of the entire grid area.

The first area grid is a grid of S≤12.5%, and the second area grid is a grid of S>12.5%.

Wherein, all of the first area lattices are blocked at the inlet surface and open at the outlet surface.

Wherein, all of the first area lattices are blocked at the exit surface and open at the inlet surface.

Wherein, the inlet surface and the outlet surface of the second area lattice are both spaced apart.

(3) Beneficial effects

The honeycomb ceramic plugging structure provided by the invention selectively blocks small incomplete lattices to meet discharge requirements, has small back pressure, good thermal shock resistance, low production cost and good filtering effect.

DRAWINGS

1 is a partial structural view of an inlet honeycomb ceramic surface according to Embodiment 1 of the present invention;

2 is a partial structural view of an outlet honeycomb ceramic surface according to Embodiment 1 of the present invention;

3 is a partial structural view of an inlet honeycomb ceramic surface according to Embodiment 2 of the present invention;

4 is a partial structural view of an outlet honeycomb ceramic surface according to Embodiment 2 of the present invention;

Figure 5 is a partial structural view of an inlet honeycomb ceramic surface according to Embodiment 3 of the present invention;

Figure 6 is a partial structural view showing the outlet honeycomb ceramic surface of Embodiment 4 of the present invention;

In the figure, 1, the first area grid; 2, the second area grid.

Detailed ways

The specific embodiments of the present invention are further described in detail below with reference to the drawings and embodiments. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the present invention, it should be noted that the terms "installation", "connected", and "connected" are to be understood broadly, and may be fixed or detachable, for example, unless otherwise explicitly defined and defined. Connected, or integrally connected; can be mechanical or electrical; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of the two components. The specific meaning of the above terms in the present invention can be understood in a specific case by those skilled in the art.

As shown in FIG. 1 to FIG. 6 , the present invention discloses a honeycomb ceramic plugging structure, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface, and the imported honeycomb ceramic surface and the outlet honeycomb ceramic surface include S≤25% at the edge of the skin. The first area lattice 1 and the second area lattice 2 of S>25%, all the first area lattices 1 are blocked at the inlet surface and/or the outlet surface; wherein S is an incomplete lattice area of a certain lattice occupying the complete lattice The proportion of the area.

The present invention is directed to a honeycomb ceramic filter having a structure in which inlet and outlet passages are interconnected by porous walls. The inlet passage is blocked at the outlet end and the outlet passage is blocked at the inlet end. With such a structure, the exhaust gas can be forced to flow from the inlet passage, pass through the porous wall, and then flow out from the outlet passage. Thus, this occlusion pattern (like a checkerboard structure) collects particulate matter within the channel. The filter of the present invention has skin, which may be circular, elliptical, or other shape, and the filter is formed by an extrusion process. Generally, the material of this filter is ceramic materials such as cordierite, silicon carbide, aluminum titanate, and mullite, but other extrudable materials such as glass, glass ceramics, plastics, and metals. . Generally, the filter of the present invention has a porosity of between 20% and 70%. For gasoline engines and diesel exhaust filters, the average pore size is between 5 and 50 microns, and more preferably between 10 and 30 microns. Honeycomb ceramic filters have 50 to 350 grids per square inch and more preferably 100 to 300 grids. The wall thickness can range from 0.05 to 0.5 mm, more preferably from 0.1 to 0.4 mm.

Specifically, S is an indicator for measuring incomplete grids. When S is close to 1, the incomplete grid is similar to the complete grid. Assuming that all incomplete grids are averaged by S values, then an incomplete grid with S equal to or less than 25% accounts for 25% of all incomplete grids. Filled in the usual checkerboard pattern, half of the grid is not blocked. From the present invention, these grids are filled, creating redundant plugging lattices. Assuming that these incomplete lattices have an S value of 25%, then all relative areas of these lattices (relative to the complete grid on the diameter line) are:

25%*π*(25%/2)=9%

The above is a conservative calculation because not all of the incomplete grids involved have S equal to 25%. Since the number of grids on the diameter line is less than 5% of the entire filter, the area affected by this design is less than 0.5% of the total filter grid number, or less than 1% of the normal checkerboard hole blocking method. Thus, if all grids with S equal to or less than 25% are filled, the effect on back pressure is small.

For the above filling design, it can be used for the inlet or outlet end, or both ends can be filled at the same time. When this method is used for simultaneous plugging at both ends, the effect on back pressure is below 2%.

Preferably, the first area lattice 1 is a lattice of S≤12.5%, and the second area lattice 2 is a lattice of S>12.5%.

Among them, all the first area lattices 1 are blocked at the inlet surface and open at the outlet surface.

Among them, all the first area lattices 1 are blocked at the exit surface and open at the inlet surface.

Wherein, the inlet surface and the outlet surface of the second area lattice 2 are both spaced apart.

Example 1:

As shown in Fig. 1 and Fig. 2, all the inlet ends of the first area lattice 1 of S ≤ 25% are blocked, and are not blocked at the outlet end. For the second area grid 2 where S is greater than 25%, the plugging interval is blocked in the usual checkerboard pattern. Through experiments and calculations, the effect of this example on back pressure is less than 1%.

Example 2:

As shown in FIG. 3 and FIG. 4, all the outlet ends of the first region lattice 1 of S≤25% are blocked, and are not blocked at the inlet end. For the second area grid 2 where S is greater than 25%, the plugging interval is blocked in the usual checkerboard pattern. Through experiments and calculations, the effect of this example on back pressure is less than 1%.

Example 3:

As shown in Figs. 5 and 6, all of the inlet end and the outlet end of the first area lattice 1 of S ≤ 25% are blocked. For the second area grid 2 where S is greater than 25%, the plugging interval is blocked in the usual checkerboard pattern. Through experiments and calculations, the effect of this example on back pressure is less than 2%.

In addition, if the extrusion process and the laser drilling process are of good quality, the S value can be further reduced to 12.5% without the problem of accuracy, as in the following Example 4 - Example 6.

Example 4:

The present embodiment is substantially the same as the first embodiment. For the sake of brevity of description, the same technical features as those of the first embodiment will not be described in the description of the present embodiment, and only the difference between the embodiment and the embodiment 1 will be described.

The first area lattice 1 of the present embodiment is a lattice with S less than or equal to 12.5%, and a second region lattice 2. The inlet end of the first area lattice 1 is blocked and is not blocked at the outlet end. The second area grid 2 is blocked by a conventional checkerboard type.

Example 5:

This embodiment is basically the same as the embodiment 2. For the sake of brevity of description, the same technical features as those of the embodiment 2 will not be described in the description of the embodiment, and only the difference between the embodiment and the embodiment 2 will be described.

The first area lattice 1 of the present embodiment is a lattice with S less than or equal to 12.5%, and a second region lattice 2. The outlet end of the first area lattice 1 is blocked and is not blocked at the inlet end. The second area grid 2 is blocked by a conventional checkerboard type.

Example 6

This embodiment is basically the same as the embodiment 3. For the sake of brevity of description, the same technical features as those of the embodiment 3 will not be described in the description of the embodiment, and only the difference between the embodiment and the embodiment 3 will be described.

The first area lattice 1 of the present embodiment is a lattice with S less than or equal to 12.5%, and a second region lattice 2. The inlet end and the outlet end of the first area lattice 1 are both blocked. The second area grid 2 is blocked by a conventional checkerboard type. Through experiments and calculations, the effect of this example on back pressure is less than 1%.

The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., which are included in the spirit and scope of the present invention, should be included in the present invention. Within the scope of protection.

Claims

A honeycomb ceramic plugging structure, comprising: an inlet ceramic ceramic surface and an outlet honeycomb ceramic surface, wherein the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface comprise a first region of S ≤ 25% at the edge of the skin a lattice (1) and a second region lattice (2) of S>25%, all of the first region lattices (1) are blocked at the inlet surface and/or the outlet surface; wherein S is an incomplete lattice of a lattice The area accounts for the proportion of the entire grid area.
The honeycomb ceramic plugging structure according to claim 1, wherein the first area lattice (1) is a grid of S ≤ 12.5%, and the second area grid (2) is a grid of S > 12.5%. .
The honeycomb ceramic plugging structure according to claim 1 or 2, wherein all of said first area lattices (1) are blocked at the inlet face and open at the outlet face.
The honeycomb ceramic plugging structure according to claim 1 or 2, characterized in that all of the first area lattices (1) are blocked at the outlet face and open at the inlet face.
The honeycomb ceramic plugging structure according to claim 1, wherein the inlet surface and the outlet surface of the second area lattice (2) are both spaced apart.