RU2320401C2 - Device for catalytic purification of exhaust gases - Google Patents

Abstract

FIELD: purification of gases.

SUBSTANCE: device comprises housing (1) with inlet branch pipe (2) and outlet branch pipe (3). Housing (1) receives the catalytic stack made of two parallel perforated plates (4) made of a stainless steel and coated with small-mesh grid (5). Loose catalyzer is interposed between plates (4). The axis of inlet branch pipe (2) is parallel to the plane of the perforated plates. Inlet branch pipe (2) underlies the catalytic stack, and outlet branch pipe is mounted above the catalytic stack on the opposite side.

EFFECT: enhanced efficiency of purification.

2 cl, 3 dwg

Description

The invention relates to methods for the catalytic purification of gases and can be used for purification of exhaust gases of various industries, thermal power plants and vehicles from hydrocarbons, nitrogen oxides and carbon monoxide.

A device for cleaning exhaust gases, comprising a housing with inlet and outlet pipes and a cartridge with a catalyst (patent RU 2134802, 1999).

For this device, the surface area of the catalyst at the entrance to the cassette and at the exit from it is not the same, therefore, the uniformity of the flow of the gas to be purified and, therefore, the cleaning efficiency are not ensured.

A device for the catalytic purification of exhaust gases, comprising a housing with inlet and outlet pipes and a cartridge with a catalyst (RU 2087726, 1997).

The disadvantage of this design, taken as a prototype, is that it does not significantly increase the contact area of the gas to be cleaned with the catalyst surface with a standard housing diameter (in particular, the diameter of the exhaust pipe). When increasing the thickness of the catalyst layer or installing the catalyst in several layers, it is difficult for the gas to be cleaned through the catalyst layer, which adversely affects the operation of the car engine.

The disadvantage of all known structures used for purification of exhaust gases of internal combustion engines is the inability to use bulk (granular) catalyst in them, the use of which leads to a significant increase in resistance to gas flow, accompanied by a decrease in power.

In addition, the disadvantages of the known devices used for purification of exhaust gases include their high cost associated with the use of precious metals in the manufacture of the catalyst.

The technical result of the claimed invention is to increase the efficiency of purification of exhaust gases by reducing the resistance to gas flow while reducing the cost of the device.

The technical result is achieved due to the fact that the device for the catalytic purification of exhaust gases includes a housing with inlet and outlet nozzles and a granular catalyst placed between two parallel perforated plates coated with a fine mesh, with the formation of a catalytic package. In this case, the inlet pipe and the outlet pipe are located at opposite edges of the catalytic package. The inlet pipe is located below, and the outlet pipe is above the catalytic package, and the axis of the inlet pipe is parallel to the plane of the perforated plates. On both sides of the package, in the spaces between each plate and the inner wall of the housing facing it, there are elastic elements designed to seal the catalyst inside the package.

In a preferred embodiment, the device case has a rectangular cross-section, and, for example, a mechanical mixture of industrial oxide catalysts: nickel-chromium oxide with a content of NiO≥48 wt.% And Cr ₂ O ₃ ≥27 wt.% And copper-zinc, is used as a catalyst. nickel grade NTK-10-1, taken in a ratio of 1: 1 to 20: 1, respectively.

The invention is illustrated by drawings, where Fig. 1 is a schematic illustration of the construction of the claimed device, Fig. 2 is a section along A-A of Fig. 1 (a variant with a cylindrical body shape), Fig. 3 is a section along A-A of Fig. 1 (version with a rectangular body shape).

A device for the catalytic treatment of exhaust gases includes a housing 1 with a pipe 2 inlet and pipe 3 gas outlet. Inside the housing 1, a catalytic package is installed in the form of two parallel perforated plates 4 of stainless steel coated with a fine mesh 5, with a bulk (granular) catalyst 6 placed between the plates 4. In this case, the axis of at least the inlet pipe 2 is parallel to the plane of the perforated plates 4. The inlet pipe 2 and the outlet pipe 3 are located at opposite edges of the catalytic package, the inlet pipe 2 is located below, and the outlet pipe 3 is higher than the catalytic package.

In the gaps between each plate and the inner wall of the housing facing it, elastic elements 7 are provided for sealing the catalyst inside the bag. As elastic elements, springs or devices of a special design can be used.

The claimed device operates as follows.

The flow of exhaust gas containing hydrocarbons and oxides of nitrogen and carbon enters the housing 1 through the inlet pipe 2. In this case, the linear flow rate decreases sharply, because the surface area of the catalytic package is much larger than the cross section of the pipe 2. It should be noted that in addition to the possibility of reducing the flow rate, the claimed design simultaneously allows you to maintain a practically constant flow rate at the inlet and outlet of the package, since the areas of the plates restricting the package are equal. This significantly increases the efficiency of neutralization of toxic compounds contained in the exhaust gases, and reduces the resistance to the flow of passing gases, which positively affects the operation of the car engine. Passing through the catalyst bed, nitrogen oxides are reduced to molecular nitrogen, carbon monoxide and hydrocarbons are oxidized to CO ₂ and water, which are removed through pipe 3 to the atmosphere.

The elastic preload of the plates 4 provides a high packing density of the catalyst particles, which eliminates its mechanical wear.

The fine mesh 5 reliably holds the catalyst particles inside the catalytic bag, preventing them from penetrating through the perforation of the plates 4.

The inlet and outlet nozzles are located in relation to the catalytic package in such a way that during operation of the device the probability of abrasion and removal of catalyst particles is reduced.

The proposed constructive solution allows to significantly increase the contact surface and at the same time maintain a uniform and fairly low linear velocity of the exhaust gas flow without reducing the vehicle’s clearance.

The use of a bulk catalyst made without the use of expensive components, such as platinum or palladium, can significantly reduce the cost of the device.

The claimed design can be recommended for use in various industries and thermal power plants when cleaning exhaust gases, as well as for cleaning exhaust gases of vehicles and mechanisms with internal combustion engines.

Claims (3)

1. A device for the catalytic purification of exhaust gases, comprising a housing with inlet and outlet nozzles and a granular catalyst placed between two parallel perforated plates coated with a fine mesh network with the formation of a catalytic package, while the inlet pipe and outlet pipe are located at opposite edges of the catalytic package, the inlet pipe is located below, and the outlet pipe is higher than the catalytic package, and the axis of the inlet pipe is parallel to the plane of the perforated plates, with that the perforated plates are urged inwardly by the elastic package elements disposed on both sides of the package in between each plate and the facing inner wall of the housing. 2. The device according to claim 1, characterized in that the housing has a rectangular cross section. 3. The device according to claim 1, characterized in that a mechanical mixture of industrial oxide catalysts is used as a catalyst: nickel chromium oxide with a NiO content of at least 48 wt.% And Cr ₂ O ₃ at least 27 wt.% And a copper-zinc-nickel grade NTK-10-1, taken in a ratio of 1: 1 to 20: 1, respectively.

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