JPH01201196A - Recombiner - Google Patents

Abstract

PURPOSE:To prevent soaring up and rolling of catalysts by forming a catalyst layer in a recombination container and providing in-net carriers formed by housing the carriers into stainless steel nets on said catalyst layer. CONSTITUTION:This recombiner 8 is constituted by forming the catalyst layer 13 in the recombination container 12 and providing the in-net carriers 20 to a laminar state on the catalyst layer 13. The off-gas entering the recombination container 12 from a gas inlet 14 collides first against the in-net carriers 20 and the flow of the off-gas A is regulated by the carriers 20. Since the carriers 20 are formed by housing alumina 24 of a granular, pellet or other state into the stainless steel nets 23, the carriers are not moved by the flow of the off-gas A. The soaring up and rolling of the catalysts are, therefore, prevented and the deviation of the catalysts in the container 12 and the dislodgment of palladium from the surface of the alumina 24 are prevented.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a recombiner, and in particular can prevent rolling of a catalyst and reduce the amount of crud attached to the catalyst. Circle into the recombiner.

(Prior Art) Generally, in a boiling water reactor, as shown in FIG. After doing the work, you will be guided to the condenser 3b. The steam guided to the condenser 3b is condensed here, becomes condensate, and is sent to the reactor 1 again through the reactor condensate water supply system 4.

Due to such operation of the nuclear reactor 1, off-gas accumulates in the upper part of the condenser 3b. In addition to radioactive krypton and xenon, this off-gas contains hydrogen produced by radiolysis of water,
Since it contains oxygen and the like and cannot be released into the atmosphere as it is, an off-gas system 5 is provided to safely process the off-gas and release it into the atmosphere.

The off-gas accumulated in the condenser 3b is first sucked in by a steam air extractor 6 that utilizes the steam flow led from the turbine system and sent to the preheater 7. The off-gas sent to the preheater 7 is preheated here and raised in temperature, and then sent to the recombiner 8, where most of the hydrogen in the off-gas reacts with oxygen due to the action of a catalyst. It is converted into water vapor.

The off-gas that has generated water vapor in the catalyst is heated by the heat of reaction, and then flows into the Arnota condenser 9. 7 The off-gas that has flowed into the lid condenser 119 is cooled here by -C,
The water vapor in the off-gas turns into water, and that water is removed. The off-gas from which water has been removed has radioactive gas and the like removed by activated carbon in the off-gas treatment device 10, and then is discharged from a stack (not shown) into a tank.

(Problems to be solved by the invention) In the conventional recombiner H, as shown in Fig. 4,
A catalyst layer 13 is formed in the recombination vessel 12, off-gas A is introduced from the gas port 14, hydrogen and oxygen in the off-gas A are reacted and treated by the action of the catalyst, and the off-gas A after the treatment is The gas is discharged from the gas outlet 15.

However, since the catalyst has a shape C such as particles or pellets with a diameter of about 5M, when the off-gas Δ is introduced from the gas population 14, the gas flow causes the catalyst to fly up and the catalyst to roll. Reference numerals 16 and 1 in Figure 5
7, inside the recombination vessel 12 ('the catalyst 13 is biased. If the catalyst layer 13 is biased and the top surface of the catalyst layer 13 is tilted, the off-gas A is
Since the off-gas A flows downward along the slope of No. 3 and mainly passes through the thin portion of the catalyst layer 13, the off-gas A cannot be properly treated.

In addition, since palladium is supported on a particulate or pellet-like alumina carrier as a catalyst, when rolling occurs on the catalyst, palladium is desorbed from the alumina surface and the recombiner 8 Performance decreases.

Furthermore, the off-gas A contains crud mixed in from the condenser 3b and the off-gas system piping, and if this crud adheres to the surface of the catalyst, the performance of the catalyst will deteriorate.

The present invention has been made in consideration of the above-mentioned circumstances, and provides a recombiner that can prevent the catalyst from flying up or rolling in the recombination container, and can reduce Wffi of cladding on the catalyst. The purpose is to

(Structure of the Invention) (Means for Solving the Problems) A recombiner according to the present invention includes a catalyst layer formed in a recombination container, and a carrier stored in a stainless steel mesh on top of the melting medium layer. The mesh carrier is provided in layers.

(Function) By providing a layered networked carrier on the catalyst layer, the catalyst is prevented from floating or rolling, and if the melting medium is uneven in the recombination vessel, desorption of palladium from the carrier surface is prevented. Ru. Moreover, the flow of off-gas is rectified by the mesh carrier, which improves the utilization efficiency of the catalyst. Furthermore, since the cladding adheres to the surface of the vA-containing carrier, the A gas is purified and the amount of cladding attached to the catalyst is reduced.

Therefore, deterioration in the performance of the recombiner can be prevented.

(Embodiment) An embodiment of the recombiner according to the present invention will be described with reference to the drawings.

The recombiner 8, as shown in FIG.
0 is provided in layers.

The recombination vessel 12 is provided with a gas port 14 and a gas outlet 15, and is provided with a manhole 21 at the top for exchanging the catalyst and the mesh carrier 20. The catalyst layer 13 has a diameter of 5s to 1
Alumina in the form of particles or pellets of about 2s (A12
It consists of a catalyst in which palladium (Pd) is supported on the periphery of 03), and the action of this catalyst promotes the bonding between hydrogen and oxygen, thereby converting hydrogen into safe water vapor.

As shown in FIG.
For example, alumina 24 in the form of particles or pellets is stored inside the bag as a carrier, and one bag can be placed between two manholes.
It has a size that allows it to be taken in and taken out from 1. For example, if the diameter of the manhole 21 is about 30 cm, the size of the mesh carrier 20 is 10 cm to 30 cm in diameter.
A size of about 11 is convenient for handling. Further, the shape of the mesh carrier 20 may be spherical or layered, and the catalyst layer 13 may be
Any material may be used as long as it forms a layer when placed on top of the layer δ.

The stainless steel net 23 needs to have a mesh size that prevents the alumina 24 inside from coming out. On the other hand, alumina 24
If the diameter is too small, the pressure loss will be greater than that of the catalyst, and if it is too large, the effect of rectifying the flow of off-gas A will be reduced, and the surface area for removing the crud will not be secured, so it is the same as the catalyst. A suitable size is approximately 5 mm in diameter, 11 to 12 mm in diameter.

Next, the operation of the above embodiment will be explained.

Off-gas A that entered the recombination vessel 12 from the gas population 14
first hits the mesh carrier 20, and the flow of the off-gas A is rectified by the mesh carrier 20.

In this case, since the mesh carrier 20 is a stainless steel mesh 23 containing alumina 24 in the form of particles or pellets, it will not be moved by the flow of the off-gas A.

Therefore, lifting and rolling of the catalyst is prevented,
Unbalanced catalyst in the recombination vessel 12 and desorption of palladium from the surface of the alumina 24 are prevented, and performance deterioration of the recombiner 8 is prevented.

Further, when the off-gas A passes through the alumina 24 of the wire-reticulated carrier 20, the cladding in the off-gas A is
It adheres to the surface of 4. Therefore, the off-gas A is purified, the amount of crud adhering to the catalyst is reduced, and deterioration in the performance of the catalyst is prevented. Furthermore, since the flow of the off-gas A is rectified by the layer of the mesh carrier 20, it passes through the catalyst layer 13 evenly, and the performance of the recombiner 8 is improved.

In this way, according to the above embodiment, the catalyst is prevented from flying up or rolling, and the amount of crud attached to the catalyst is reduced, so that the performance of the recombiner 8 is prevented from deteriorating.

In the above embodiments, a recombiner for an off-gas system of a boiling water nuclear reactor has been described, but the present invention can be used as other general recombiners.

(Effects of the Invention) In the recombiner according to the present invention, a catalyst layer is formed in the recombination container, and a wired carrier containing a carrier in a stainless steel mesh is provided in a layer on the catalyst layer. It is possible to prevent the soaring up and rolling of the catalyst, and also to reduce the adhesion ω of the crud to the catalyst, and as a result, it is possible to prevent the performance of the recombiner from deteriorating.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a recombiner according to the present invention, and FIG. 2 is a block diagram showing a network carrier in the above embodiment.
Figure 3 is a block diagram of a general off-gas system, Figure 4 is a block diagram of a conventional recombiner, and Figure 5 is a block diagram of a conventional recombiner in which the catalyst layer is uneven. It is. 8... Recombiner, 12... Recombination container, 13...
Catalyst layer, 20... Reticulated carrier, 23... Stainless steel mesh, 24... Alumina, A... Off gas. Figure 4 Figure 5

Claims (1)

[Claims] A recombiner characterized in that a catalyst layer is formed in a recombiner container, and a mesh carrier in which the carrier is housed in a stainless steel mesh is provided in a layer on the catalyst layer.