RU226189U1 - DETAIL OF THE SUPPORTING DEVICE OF THE CATALYTIC SYSTEM FOR THE CONTACT APPARATUS FOR AMMONIA OXIDATION - Google Patents

Abstract

The utility model relates to the chemical industry, namely to the production of nitric acid, and can be used in contact devices for the oxidation of ammonia as a support for a catalytic system, which includes a primary catalytic system containing metal meshes made of platinum group metals, and also includes a bulk element . A part of the supporting device of the catalytic system for a contact apparatus for the oxidation of ammonia contains a ring-shaped washer with an upper surface, on which there are guides oriented upwards, made with the possibility of laying load-bearing beams in them. In addition, the washer has protrusions oriented inside the washer and configured to support the load-bearing beams. The use of a utility model makes it possible to increase the reliability of the support device of the catalytic system for ammonia oxidation spacecraft while maintaining a minimum pressure drop of the gas mixture and, as a result, increase the uninterrupted operation life of the spacecraft. 8 salary f-ly, 3 ill.

Description

Technical field

The utility model relates to the chemical industry, namely to the production of nitric acid, and can be used in contact devices for the oxidation of ammonia as a support for a catalytic system, which includes a primary catalytic system containing metal meshes made of platinum group metals, and also includes a bulk element.

State of the art

One of the main installations in the nitric acid production scheme is a contact apparatus (hereinafter referred to as KA) for the oxidation of ammonia, in which a mixture of ammonia and atmospheric oxygen interacts at an elevated temperature on a catalytic system using platinum group metals, until an ammonia-air mixture is formed, purified from dust is fed from top to bottom into the spacecraft in which the catalytic system is located. The first along the gas flow is a primary catalyst in the form of meshes made of platinum group metals. Below such a catalyst along the gas flow, a collecting material can be installed to collect volatilized platinum group metals. As a rule, the primary catalyst and trapping material are metal meshes that form a package of the primary catalytic system, attached to the spacecraft structure with clamps. To separate and support the catalyst and trapping mesh layers, base metal meshes such as fechral are typically included in the package.

The metal meshes of the primary catalytic system rest on a bulk element located in the basket. A bulk element is understood as a bulk material, part of a catalytic system, made, for example, in the form of particles or granules and manufactured by extrusion, tabletting, crushing, 3D printing or other known methods. The bulk element may be catalytic or not perform a catalytic function at all and be an inert or absorbent material. Thus, the bulk element is often a second-stage catalyst for the oxidation of ammonia, a catalyst for the decomposition of nitrous oxide (N ₂ O), an inert material to improve heat and mass transfer, or a absorbent material to capture platinum group metals. The basket is fixed to the spacecraft body.

Below the basket in the spacecraft there are supporting means in various designs, designed to perform the main load-bearing function for the bulk element.

In existing designs of devices for placing a catalytic system in a spacecraft, grates with ribs intersecting at an angle of 90° are used, located on supporting beams, or self-supporting structures made in the form of a combination of rigidly connected concentric and radial ribs. A supporting mesh is placed on top of them under the bulk element. During operation of the equipment, the supporting mesh under the bulk element made of base metals is often deformed and sags between the ribs of the grid, causing displacement of the bulk element and a change in the thickness of its layer, resulting in the formation of dips and slides.

Changing the height of the layer of a bulk element, in addition to reducing its efficiency, also causes deformation and premature destruction of meshes made of platinum group metals, which poses a problem, since the efficiency of ammonia oxidation decreases, the run time decreases, the loss of platinum group metals increases and there is a danger of ammonia leakage, which may lead to the formation of nitrite and ammonium nitrate in downstream equipment.

In addition, load-bearing grates with ribs have increased metal consumption, create an increased pressure drop and are more susceptible to damage during operation due to temperature deformations at the junctions of its elements, especially if the temperature distribution is uneven across the cross section of the grate. The designs of such gratings are “rigid” and prone to warping. A similar detail of the support device of the catalytic system for ammonia oxidation spacecraft is known from document US 2017239635 A1, publ. 08/24/2017 (item 160).

The above-described disadvantages are devoid of the part of the supporting device of the catalytic system for the ammonia oxidation spacecraft (PL 236240 B1, published on December 28, 2020), selected as a prototype and containing a ring-shaped washer, on the upper surface of which there are vertical guides designed to place load-bearing beams between them. A support grid with a supporting mesh is placed on the beams, above which there is a screen with a flange in the upper part for fastening to the spacecraft body and a lower part bent inward. A means of securing the primary catalytic system screens is used above the screen flange.

The main drawback of the prototype is related to the placement of the load-bearing beams. To prevent the possible fall of beams and their retention on the washer during thermal deformations, it is necessary to increase the width of the washer, which leads to increased metal consumption, and in a number of structures, to a decrease in the effective diameter of the spacecraft.

Disclosure of the essence of the utility model

The problem that the utility model is aimed at solving is to create a part for the support device of the catalytic system for ammonia oxidation spacecraft, devoid of the above-described disadvantages of analogs and the prototype.

The technical result consists in increasing the reliability of the support device of the catalytic system for ammonia oxidation spacecraft while maintaining a minimum pressure drop of the gas mixture and, as a consequence, increasing the uninterrupted operation life of the spacecraft.

The specified result is achieved by a part of the supporting device of the catalytic system for the contact apparatus (CA) of ammonia oxidation, containing

an annular washer with an upper surface containing upwardly oriented guides configured to accommodate load-bearing beams,

wherein

the washer has protrusions oriented inside the washer and configured to support load-bearing beams.

The use of upward-oriented guides allows the length of the beams to change and their displacement in the horizontal plane, i.e. along the upper surface of the annular washer, within the guides during temperature deformations, and the protrusions oriented inside the washer provide the best ability to hold the beams with minimal likelihood of them falling, which increases the reliability of the supporting device of the catalytic system while maintaining a minimum pressure drop of the gas mixture, and also reduces the likelihood the formation of slides and failures of the bulk element and damage to the grids of the catalytic system due to the distortion of the support grid caused by the fall of the supporting beam. This part allows you to increase the uninterrupted operation of the spacecraft.

In a preferred embodiment, the guides are configured to accommodate load-bearing beams at an angle of 0-10° to each other, preferably at an angle of 0-5° to each other. This design better ensures the reliability of the supporting device for the catalytic system, as it reduces the likelihood of lateral displacement of the beams along the surface of the washer due to placement in the guides intended for this, and also reduces the likelihood of skew of the grid placed on the beams due to parallel or similar placement of the beams . This makes it possible to further increase the uptime of the spacecraft.

Also, in a preferred embodiment, the guides are designed to accommodate from four to twenty load-bearing beams. This number of beams further increases the reliability and load-bearing capacity of the supporting device for the catalytic system while ensuring a minimum pressure drop of the gas mixture. This makes it possible to further increase the uptime of the spacecraft.

Preferably, the guides are arc-shaped pads for the washer, made on its surface at a distance from each other. Making the guides in this manner more effectively helps to keep them from horizontal displacements and increases the reliability of the supporting device. This makes it possible to further increase the uptime of the spacecraft.

Advantageously, the distance between the guides for each beam exceeds the width of the corresponding beam by no more than 20%, preferably by no more than 10%. This distance more effectively ensures the reliability of the supporting device, since the beams are able to experience thermal deformations without undesirable effects on the washer and other structural elements, and at the same time are not subject to lateral (horizontal) displacements along the upper surface of the washer. This makes it possible to further increase the uptime of the spacecraft.

More preferably, the projections are configured to support two to ten outer support beams. The outermost beams are most at risk of falling due to thermal deformations, so making projections for only two to ten beams is more effective in terms of reducing the likelihood of destruction of the support system, provided that the pressure drop of the gas mixture is maintained at a minimum, since the fewer projections, the less gas will encounter on your path of resistance. This makes it possible to further increase the uptime of the spacecraft.

Preferably, at least part of the protrusion is located at an angle of no more than 5° to the plane of the upper surface of the washer, preferably no more than 1°.

A smaller slope angle of the protrusions contributes to better retention of the load-bearing beams - the closer the protrusions are to the horizontal position, the lower the likelihood of the beams slipping. This makes it possible to further increase the uptime of the spacecraft.

More preferably, the projections are stepped.

No less preferably, each protrusion is 1.5-3 times wider than the corresponding beam.

The stepped shape of the protrusions, as well as the stated width of the protrusions, better contribute to holding the load-bearing beams while providing less resistance to the gas flow. This makes it possible to further increase the uptime of the spacecraft.

Brief description of drawings

The utility model is illustrated with the help of FIGS. 1-3, shown for illustrative purposes only. It will be obvious to a specialist that other embodiments of the utility model are possible, not shown in Figs. 1-3.

Figure 1 shows a preferred embodiment of a part in the form of an annular washer with guides oriented upward and with support beams placed between them, as well as with stepped projections to support the outer support beams.

Figure 2 shows a bottom view of a washer-shaped part with stepped protrusions.

Figure 3 schematically shows a disassembled support device for placing the catalytic system in the ammonia oxidation spacecraft.

The following elements are shown schematically in the figures:

1 - ring-shaped washer;

2 - upward-oriented guides on washer 1;

3 - protrusions on washer 1;

4 - load-bearing beams;

5 - support grid;

6 - supporting mesh;

7 - screen;

8 - mesh fastening means;

9 - brackets on KA 10 for placing washer 1;

10 - CA of ammonia oxidation.

Implementation of a utility model

Below are examples of the implementation of a utility model with the implementation of the purpose and with confirmation of the possibility of achieving a technical result with links to graphic materials. These examples are given solely for demonstration purposes and in no way limit the scope of the claims; a specialist will understand the various possibilities for implementing a utility model to achieve a technical result.

A part of the support device of the catalytic system for the ammonia oxidation KA 10 (Fig. 1) includes a ring-shaped washer 1 (a flattened ring shape known from fasteners), containing on the upper surface upwardly oriented guides 2, made with the possibility of laying load-bearing beams 4 in them, when In this case, the washer 1 has protrusions 3 oriented inside it, designed to support the load-bearing beams 4.

Washer 1 is located inside spacecraft 10 on brackets 9 or another support structure of the spacecraft. The guides 2 on the washer are made with the possibility of laying the load-bearing beams 4 in them at an angle of 0-10° to each other, preferably at an angle of 0-5° to each other, that is, parallel laying of the beams 4 is preferable. Also, the guides 2 are made with the possibility of laying the beams 4 in an amount from four to twenty, while the distance between the guides for each beam exceeds the width of the corresponding beam by no more than 20%, preferably by no more than 10%. The guides 2 are preferably arched pads for the washer, made on its surface at a distance from each other (Fig. 1), however, other options are possible, for example, upwardly oriented ribs on the upper surface of the washer 1.

The outermost two to ten beams (from one to four beams on each side) are additionally supported by protrusions 3 (two protrusions per beam), made predominantly stepped. Moreover, each protrusion is 1.5-3 times wider than the corresponding beam. It is also advantageous that at least part of the protrusion is located at an angle of no more than 5° to the plane of the upper surface of the washer, preferably no more than 1°.

Both the guides 2 and the projections 3 are made as a single unit with the washer 1 or are rigidly installed on it as separate elements during production at the manufacturer.

The guides 2 act as limiters of the lateral displacements of the beams 4 along the surface of the washer 1 and allow the beams 4 to experience thermal deformations and movements separately from the washer 1, mainly in the horizontal plane back and forth. And the projections 3 prevent the outermost load-bearing beams 4, which are most susceptible to this risk, from falling. These guides 2 and protrusions 3 can have different shapes, materials, thicknesses and be used in different quantities; they will be clear to a person skilled in the art and will be selected by him based on operating conditions and the type of spacecraft 10.

In addition to the claimed part containing an annular washer 1, the supporting device mainly includes a support grid 5 placed on the supporting beams 4, a supporting mesh 6 laid on said grid 5, a screen 7 forming a place to accommodate the bulk element with an internal bend in the lower part and a flange in the upper part for fastening to the body of the spacecraft 10, as well as a means 8 for fastening the grids of the primary catalytic system above the flange of the screen 7, implemented, for example, in the form of a weight (weighted ring) or a pressure flange (Fig. 3).

The proposed utility model works as follows.

A gas mixture containing ammonia, nitrogen and oxygen is fed into the ammonia oxidation spacecraft 10 from above. First, the gas mixture on its way encounters a primary catalytic system containing networks of platinum group metals, on which the exothermic reaction of ammonia oxidation occurs. The temperature of the reacted gas mixture rises to 750-950°. Immediately below the grids of the primary catalytic system, the gas encounters a bulk element in the form of catalytic, inert and/or absorption granules, limited by the walls of the screen and a supporting grid lying on the support grid.

After the bulk element, the high-temperature gas mixture passes through the support grid, supporting beams and the washer holding them.

The supporting beams 4, located between the upwardly oriented guides 2 on the surface of the ring-shaped washer 1, experience thermal deformation and move only back and forth along the mentioned guides 2 and are less susceptible to falling than if they were moving along the surface of the washer without guides. The extreme beams 4, subject to the greatest displacements, are additionally supported by stepped projections 3, oriented inside the washer 1, and do not fall out.

The reacted gas mixture leaves the spacecraft and enters the next technological unit for cooling.

Below are specific examples of implementation of the proposed device.

Example 1

A ring-shaped washer is placed on the supports of the ammonia oxidation spacecraft. The upper surface of the washer contains upwardly oriented guides in the form of ribs, between which four load-bearing beams are laid at an angle of 5° to each other. The distance between the ribs is 10% greater than the width of the beam laid between them. The washer also has four protrusions, oriented inward and located at an angle of no more than 0° to the plane of the upper surface of the washer (that is, horizontal protrusions in the specified plane), to support two outer beams (one on each side). Each mentioned protrusion is 1.5 times wider than the corresponding beam.

On the beams there is a load-bearing support grid of the grate structure with a supporting mesh located on it. The edges of the mentioned mesh extend onto the inner bend of the screen. The upper part of the screen goes into a flange, which is attached to the spacecraft body. The primary catalytic system is secured to the spacecraft above the screen flange with clamps.

Example 2

A ring-shaped washer is placed on the brackets of the ammonia oxidation spacecraft. The upper surface of the washer contains upwardly oriented guides, which are arched linings made at a distance from each other. A total of twenty load-bearing beams are laid on the washer at the indicated distances at an angle of 10° to each other. Each distance mentioned is 20% greater than the width of the corresponding beam being laid. The washer also has twenty stepped projections, oriented inside the washer and having parts located at an angle of no more than 5° to the plane of the upper surface of the washer, to support ten outer beams (four on each side). Each mentioned projection is 3 times wider than the corresponding beam.

On the beams there is a load-bearing support grid of a honeycomb structure with a supporting mesh located on it. The edges of the mesh extend onto the inner bend of the screen with a cone-shaped part facing this mesh with its narrowing. The screen is made of solid sheet metal. The upper part of the screen goes into a flange, which is attached to the spacecraft body. The primary catalytic system is fixed to the spacecraft above the screen flange using a clamping flange.

Example 3

A ring-shaped washer is placed on the annular support of the ammonia oxidation spacecraft. The upper surface of the washer contains upwardly oriented guides, which are arched linings made at a distance from each other. A total of ten load-bearing beams are laid on the washer at the indicated distances at an angle of 0° to each other, that is, in parallel. Each distance mentioned is 15% greater than the width of the corresponding beam being laid. The washer also has eight stepped projections, oriented inside the washer and having parts located at an angle of no more than 1° to the plane of the upper surface of the washer, to support the four outer beams (two beams on each side). Each mentioned protrusion is 2 times wider than the corresponding beam.

On the beams there is a load-bearing support grid of a honeycomb structure with a supporting mesh located on it. The edges of the mesh extend onto the inner bend of the screen with a cone-shaped part facing this mesh with its narrowing. The screen is made of solid sheet metal. The upper part of the screen goes into a flange, which is attached to the spacecraft body. The primary catalytic system is fixed to the spacecraft above the screen flange using a clamping flange.

The above-described embodiments are provided for purposes of illustration only. It will be obvious to one skilled in the art that other embodiments are possible.

Thus, when using this utility model, the reliability of the supporting device of the catalytic system for ammonia oxidation spacecraft is increased while maintaining a minimum pressure drop of the gas mixture due to the following, both in combination and separately:

the possibility of changing the length of the beams and their displacement in the horizontal plane within the guides on the upper surface of the washer;

providing support with protrusions for the beams most prone to falling out due to their back-and-forth displacements during temperature deformations;

The ring-shaped washer has better holding power due to its larger surface area than a conventional thin ring.

The proposed design of the utility model, in comparison with the prototype, made it possible to increase the uninterrupted operation life of the spacecraft by 25-30.

Claims (9)

1. A part of the supporting device of the catalytic system for a contact apparatus for the oxidation of ammonia, containing a ring-shaped washer with an upper surface, which contains upwardly oriented guides, made with the possibility of laying load-bearing beams in them, characterized in that the washer has protrusions oriented inside the washer and made with the ability to support load-bearing beams. 2. The part according to claim 2, characterized in that the guides are made with the possibility of laying load-bearing beams in them at an angle of 0-10° to each other, preferably at an angle of 0-5° to each other. 3. The part according to claim 1, characterized in that the guides are designed to accommodate from four to twenty load-bearing beams. 4. The part according to claim 1, characterized in that the guides are arc-shaped pads for the washer, made on its surface at a distance from each other. 5. The part according to claim 1 or 4, characterized in that the distance between the guides for each beam exceeds the width of the corresponding beam by no more than 20%, preferably by no more than 10%. 6. The part according to claim 1, characterized in that the protrusions are designed to support from two to ten outer load-bearing beams. 7. The part according to claim 1, characterized in that at least part of the protrusion is located at an angle of no more than 5° to the plane of the upper surface of the washer, preferably no more than 1°. 8. The part according to claim 1, characterized in that the protrusions are stepped. 9. The part according to claim 1, characterized in that each protrusion is 1.5-3 times wider than the corresponding beam.