RU2537956C1 - Passive autocatalytic hydrogen and oxygen recombiner with lateral intake of hydrogen-air mixture - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: passive autocatalytic hydrogen and oxygen recombiner comprises a central vertical box (1) connected to lateral sleeves (2), each holding at least one assembly of catalytic elements (3). In the disclosed apparatus, each lateral sleeve (2) has open ends (2.1), (2.2) and parallel longitudinal walls, closed on the entire perimeter of the cross-section of the sleeve (2). Each assembly of catalytic elements (3) is placed in the lateral sleeve (2) symmetrical to its upper and lower longitudinal walls 2.3) and (2.4), respectively. The lateral sleeves are inclined at an angle α=(20-80)° to said box (1).

EFFECT: high specific capacity of the recombiner.

2 cl, 4 dwg

Description

Technical field

The invention relates to the field of hydrogen safety and can be used to prevent the accumulation of flammable and explosive hydrogen in rooms, in particular, when hydrogen leaks, for example, from the cooling system of power plant generators, in hydrogen storage, during storage of nuclear waste, during high-temperature corrosion processes, during accidents at nuclear power plants (NPPs), etc.

State of the art

The work of a passive autocatalytic hydrogen and oxygen recombiner (hereinafter: “recombiner”) is based on the occurrence of an exothermic reaction between hydrogen and oxygen in the air:

$$H_2+\raisebox{1ex}{$\mathrm{one}$}\!\left/ \!\raisebox{-1ex}{$2$}\right.{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="00000003.png,00000004.png"\; state="\{\{state\}\}">O</figure-callout>}}_2\to H_{2}O\left(P\mathrm{but}R\right)+244,05\mathrm{to}D\mathrm{well}\text{(one)}$$

The recombiner is usually made in the form of a vertically located hollow body, freely communicated in its upper and lower ends with the environment and with the catalytic elements installed in its lower part (RU 52244, G21C 9/06, 2005 [1] analog). As the active part of the catalytic element (CE), platinum group metals are used, most often platinum itself, dispersed in a porous FE carrier made of ceramics, metal oxides, for example, γ-Al ₂ O ₃ , porous stainless steel, and other thermo and corrosive -resistant materials. When hydrogen and oxygen come into contact with the catalyst, the autocatalytic reaction (1) begins, the heat of which creates an upward convective flow inside the recombinator case, which, in the presence of hydrogen in the surrounding space, constantly supports the process of its recombination.

At the same time, modern recombiners do not fully satisfy the needs of practice. Their improvement takes place in different directions, including in the direction of increasing specific productivity, expressed by the rate of hydrogen removal per unit cross-sectional area of the recombiner. The fact is that a modern recombiner sucks in a gas stream through the lower hole of the cylindrical body, where the assembly of the FE (SCE) is located. The height of the SKE is usually (120-150) mm, the height of the casing is about 1000 mm. These geometric characteristics are determined by two interrelated parameters of the recombiner: its SCE performance and hydraulic resistance to gas flow both in the SCE itself and in other parts of the flow path up to the outlet pipe with a metal mesh that prevents the spread of flame and the exit of the incandescent hot aerosols. There are two ways to increase the productivity of the recombinant by increasing the volume of the catalyst it holds: in height and in the cross section of its body. But since the increase in the volume of the catalyst along the height of the recombiner case is limited by the hydraulic resistance of the SCE, acceptable within the maximum (120-150) mm of water. Art., in practice, resort to increasing the cross-sectional area of the body of the recombiner. In addition, the dimensions of the recombiner are also limited by production conditions and are usually for a single recombiner about 200 mm wide and not more than 1,500 mm in height. To save space, recombiners are usually placed on the walls of the room and at a certain height above the level of its floor. If there had been no sharp drop in the convective flow velocity caused by the hydraulic resistance of the SCE, then to increase the productivity of the recombinator, it would be possible to increase the filling of the recombinator casing with the catalyst in height (the height of production rooms, in particular, nuclear power plants, is tens of meters).

The problem of the limited performance of recombiners can be solved by changing the classic design of its body, usually made in the form of a vertical pipe.

A known recombiner containing a Central vertical trunk box with attached side arms, in each of which is placed at least one SKE (RU 113404, G21C 9/06, 2012 [2] - prototype). According to the prototype [2] the side arms of the recombiner for the formation of the input intake window are made with an open bottom longitudinal wall. In this case, the end face of each side sleeve remote from the stem box is completely closed, the proximal end of the sleeve adjacent to the stem box is closed in the lower part from the side of the SKE, and the upper longitudinal wall of the sleeve is raised from its remote end to the near end to organize in each sleeve the gas flow along the SCE from the bottom up with its subsequent discharge into the stem box through the opening above the closed part of the end face of the sleeve adjacent to the stem box.

Such a technical solution cannot provide a sufficiently large increase in the specific productivity of the recombiner due to the excessive volume of free space of the sleeve above the SCE, as well as due to the additional hydraulic resistance created by the change in the direction of the gas flow over the SCE before it enters the stem box.

Disclosure of invention

The task of the invention is to increase the specific productivity of the recombiner, and the technical result achieved is to minimize the free space between the SCE and the walls of the side arms of the stem box of the recombiner.

These tasks and the technical result of the invention are ensured by the fact that in a recombiner containing a central vertical trunk box with attached side arms, in each of which at least one SLE is placed, according to the invention, each side arm is made with open ends and parallel longitudinal walls, closed around the perimeter of the cross section of the sleeve, and each SCE is located in the side sleeve symmetrically with respect to its upper and lower longitudinal walls. In this case, the side arms are preferably inclined, at an angle of (20-80) ° to the stem box.

A causal relationship between the distinguishing features of the invention and the indicated technical result is that the implementation of the side sleeve with open ends and parallel longitudinal walls closed around the entire perimeter of its cross section allows you to change the direction of movement in the side arms of the gas stream from the direction traditional for the recombiner from bottom to top in a direction along the axis of the sleeve, perpendicular to its cross section. The movement of the gas stream along the axis of the sleeve eliminates the need for free space above the SCE, which makes it possible to arrange them inside the sleeve symmetrically with respect to its upper and lower longitudinal walls, thereby ensuring the most dense filling of the sleeve with a catalyst, which is the technical result of the invention, which allows to solve the task of increasing the specific productivity of the recombiner. The location of the side arms is oblique, at an angle of (20-80) °, to the stem box, since it allows reducing the dimensions of the recombiner and its hydraulic resistance associated with the rotation of the gas flow when leaving the side arms to the central stem box.

Brief Description of the Drawings

Figure 1 schematically shows a recombiner according to the prototype [2]; figure 2 is the same according to the claimed invention; figure 3 is one of the side arms of the recombiner according to the claimed invention in axonometric projection; figure 4 shows a graph characterizing the catalytic activity of the recombiner with side arms according to the invention in comparison with the catalytic activity of the recombiner with the vertical movement of the gas flow relative to the FE.

DETAILED DESCRIPTION OF THE INVENTION

The recombinator contains a central vertical trunk 1 with attached side arms 2, each of which has at least one SKE 3 with CE 4. According to the prototype [2], the side arms 2 are formed with an open lower longitudinal wall 2.1 to form an input intake window 2.1 (figure 1). At the same time, the end face 2.2 of each side sleeve 2 remote from the stem box 1 is completely closed, the proximal end face 2.3 of the sleeve 2 adjacent to the stem box 1 is closed in the lower part from the side of the SKE 3, and the upper longitudinal wall 2.4 of the sleeve 2 is made with a lift from its remote the end face 2.2 to the near end face 2.3 for organizing in each sleeve 2 the gas flow along the SCE 3 from the bottom up with its subsequent discharge into the trunk box 1 through the opening 1.1 above the closed part of the end face 2.3 of the sleeve 2 adjacent to the stem box 1. In contrast to the prototype [ 2] according to s to the claimed invention (figure 2, 3) each side sleeve 2 is made with open ends 2.2, 2.3 (figure 2) and parallel longitudinal walls closed around the entire perimeter of the cross section of the sleeve, and each SLE 3 is located in the side sleeve 2 symmetrically with respect to to its upper and lower longitudinal walls, respectively, 2.1 and 2.4. Side sleeves 2 are preferably located obliquely, at an angle α = (20-80) °, to the trunk 1 to reduce the dimensions of the recombiner and reduce the hydraulic resistance associated with the rotation of the gas stream at the entrance to the stem box 1.

As can be seen from figure 2, 3 in the recombiner according to the claimed invention there is no free space above the SKE 3, since KE 4 are evenly placed (with the necessary gaps between them) throughout the volume of the side arms 2, thereby achieving an increase in the specific productivity of the recombiner.

FEs can be of various shapes, preferably with a carrier made of porous stainless steel or other lamellar or cylindrical material, which exhibits minimal resistance to the gas flow around the FEs.

The operation of the recombiner according to the invention does not fundamentally differ from the work of the known recombiners described above in the section on the prior art, except that the gas flow inside the side arms 2 does not occur from the bottom up, like all previously known recombiners, but along these arms perpendicular to their cross-section, which in combination with the above structural distinguishing features allows to achieve the technical result of the invention noted above.

Industrial use of the invention

Pilot samples of the recombiner according to the invention of the RBC model (a recombinator with a catalyst in the side arms), in particular, RBC-6, RBC-10, RBC-80, where the numbers on the right indicate the total number of arms adjacent to the stem box, were created and tested. In Fig. 1, the catalytic activity of the recombinant RBC model is demonstrated by the dependence of the specific RBC productivity on the hydrogen concentration in the ambient air (curve 1). The tests were carried out in a chamber with a volume of 550 l with a continuous supply of a gas mixture. The temperature in the chamber was maintained at 25 ° C. For comparison, the same graph shows a similar dependence for a recombiner with a vertical movement of the gas flow relative to the FE (curve 2). It should be noted that the assessment of the specific productivity per unit area of the stem box is justified not only for the mine-type recombiner, but also for RBC, the dimensions of which (including the dimensions of the arms) are slightly larger than the cross-sectional area of its trunk box. With an increase in the height of the RBC and the number of sleeves, the performance of the RBC increases proportionally while maintaining the overall dimensions of the recombiner in plan and in width.

To increase the height of the RBC, there are practically no fundamental obstacles if there are no problems associated with the manufacturing technology or with the space of the walls of the room. The cross-sectional area of the trunk for the RBC-80 model (40 sleeves on each side of the trunk) is 100 × 200 mm, height is 1040 mm, and the overall dimensions (with sleeves) in the plan are 200 × 300 mm.

Claims (2)

1. A passive autocatalytic hydrogen and oxygen recombiner containing a central vertical trunk box with attached side arms, each of which has at least one assembly of catalytic elements, characterized in that each side arm is made with open ends and parallel longitudinal walls, closed around the perimeter of the cross section of the sleeve, and each assembly of catalytic elements is located in the side sleeve symmetrically with respect to its upper and lower longitudinal n walls. 2. The passive autocatalytic recombiner according to claim 1, characterized in that the side arms are located obliquely, at an angle of (20-80) °, to the stem box.

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