JPS5954946A - Method for detecting leakage from filter filled with silver zeolite - Google Patents

Abstract

PURPOSE:To detect the leakage from an iodine removing filter by using the gas of a material having physical adsorption property, by flowing the gas under the state small holes, which have adsorption activity for the condensating gas of silver zeolite, remain. CONSTITUTION:A treating gas is flowed in an iodine filter housing 1. The treating gas is heated by a heater 2. The ratio between steam pressure P and saturated steam pressure Ps in an atmosphere is made to be 0.2 or less. Under this state aeration is performed for a specified time period, e.g., for 0hr when the silver zeolite does not absorb the water and about 10hr when the silver zeolite absorbs the water to the extent of 0.11cm<2>/g. Thereafter Freon is introduced from a Freon generator 4 together with a carrier gas such as air. After the introduction is stabilized, part of the aeration gas is introduced to a Freon concentration measuring device 5 from the upstream side and downstream side of a silver zeolite filled filter 3, the Freon concentration is measured, and the leakage rate is computed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Original Field of the Invention] The present invention relates to a leak detection method for a filter filled with silver zeolite. □ [Conventional technology]
□ In nuclear power plants and other nuclear power plants, high-performance iodine removal filters with a removal rate of 96% or more are installed in order to completely prevent the release of radioactive gases, especially radioactive iodine, from the standpoint of environmental protection. -□ In order to maintain the full performance of the iodine removal filter, 5.
The use of high-quality iodine adsorbents is a must.

Needless to say, when a high-performance iodine adsorbent is used, when converting to a tail J device, the packed bed of this adsorbent will have a load of ~1 m momme.
5. The 14th layer of the stone was present. If a bypass line □ exists in the filter frame or gasket, the performance of the entire filter device will deteriorate. - Therefore, it is necessary to conduct regular leak tests during and after installing the iodine removal filter. In addition, an adsorbent, or impregnated charcoal, was used for the iodine removal filter, and for leak detection, Freon, which is physically stratified, was used for the impregnated charcoal.
On the other hand, in recent years, attempts have been made to use silver zeolite as an iodine adsorbent with high performance and longevity in place of conventional impregnated carbon in iodine removal filters. However, when using it to detect leaks in filters that remove filters that are empty, empty, or empty, it is important to
Due to the small adsorption power of Rheo/, the concentration at the outlet of the filter was high, making it impossible to detect leaks from the filter.
・[Object of the invention] ・The present invention is a method for detecting leakage in an iodine removal filter using silver zeolite'x adsorbent.
The purpose is to make it possible to implement K with 'JIJ'lx.

□ [Summary of the invention] The present invention provides silver zeolite packed as an adsorbent.
In the method □ for detecting leakage in a build-up/removal filter, all the characteristics are as follows: gas of the physisorptive substance W = vaporized in a state where yial pores having stratification activity against condensable gas remain on the silver zeolite. However, according to the present invention, when Freon is used to remove iodine using silver zeolite to detect leaks, the cause of the decrease in the adsorption power of Freon is water vapor applied to silver zeolite with a condensable gas. This is based on the fact that when silver zeolite is adsorbed, 7 sulfur-blown sites are buried, and in order to eliminate this effect, for example, it is necessary to The condensed liquid is 0.11 cm3 (O9i'1 g in the case of water) or less, □ or '□-like phosphor □ The saturated vapor pressure of the condensable gas, relative to the vapor pressure P of the condensable gas in the gas vented to the olide adsorbent, The Ps ratio P/Ps'i is set to 0.2 or less to completely eliminate its influence and to make it possible to completely detect leaks using Freon kidneys.

The study results will be explained below.

Silver zeolite that is rarely used as an iodine adsorbent is crystalline zeolite Na20:A, t20a:m5i02
: nl (20 (where m, , n is a value that increases depending on the tie of Zesulite, and in the case of N type, m books 2.
5 ± 0.5, n = 6.2-8. ) Inferior, as a base, and replace this base with all Na and Ag? It is. Zeolite thus has the ability to be mixed with other metals such as NakAg, which is one of the unique characteristics of zeolite, and various substitutes have been widely used in catalysts and other applications. There are, but
Another major feature is that the pores have a uniform pore size of 4 after the water collected as crystal water in the zeolite is removed by drying. These pores serve as adsorption sites for various gases such as pores and fluorine gases.
Because the pore size is small (on the order of a person) and uniform, the adsorption properties vary depending on the molecular size of the adsorbed gas, so it is called a molecular sieve.
(Mobicular sieve).

Iodine removal using silver zeolite utilizes the ability of zeolite to replace Ag, which chemically fixes iodine, with Na in zeolite.
It is carried out by fixing it on zeolite. Freon adsorption used for leak detection is performed by utilizing the adsorption properties of the pores after the crystal water has been removed. However, since the pores after the crystal water has been removed completely adsorb various condensable gases, if a large amount of condensable gases are present, the pores are buried and no gases are deposited on the pores. In particular, when the condensable gas is water vapor: for example, when the general atmosphere contains a large amount of water vapor, water vapor is also adsorbed into the zeolite and is strongly adsorbed as crystal water.

Therefore, leak detection of the iodine removal filter cannot be performed in the general atmosphere.

Therefore, the adsorption of condensable gas to silver zeolite is
Figure 1 shows the experimental results for water vapor, where the horizontal axis shows the water vapor pressure (p) in the atmosphere, and the vertical axis shows the water vapor pressure (p) in the atmosphere. Equilibrium of water for 'm = l, i -3 water/g adsorbent) is a well-known example, 'A epilepsy Mze □ Oh □ If the arm is hydrated, Bi' ratio 1 lfi 2 mota □ - In the case of carbonization, 1 is shown, and C is in the range of the atmosphere inside the waste power station. The amount of water δ millet applied to t zeolite is P'/
There is a tendency to increase as P′s□ increases, but
pZPs force IK O, 2 is a sudden increase in force i, □0.2
．． On fM, there is an increase of 1 (2)) or □. Water absorption with P'/p'' s□ of 0.2 or less is due to absorption of famous water in the human-order pores of zeolite, that is, pores with adsorption activity, and P'/P. '
When the s system is 0', 2 or more, the pores on the adsorption side of each gas are filled with □water, and other gases are no longer adsorbed.As a result, freon and other gases are In order to adsorb other gases, the condensable gas P/
P"'s system "O', less than or equal to 2, that is: 1st figure D
In other words, the amount of water adsorbed is within the range of O
', 11 cm"/g"(0,'l 1 water/g
゛ □ [Embodiments of the invention] □ Below, □ Implementation progress will be explained □ 21st - Implementation of the embodiments □This is a diagram showing the flow of the equipment. 1 is the iodine filter □zinc, 2 is the heater, 3 is the silver zeolite □filter, 4 is the Freon generator, 5 is the Freon meter, and the iodine filter housing. A heater 2 is installed on the inlet side of the processing gas in the chamber 1, a filter 3 filled with silver zet is installed on the output side of the process gas, and a filter 3 is installed on the upper floor side of the filter housing 1.
The piping from the Freon generator 4 is connected to J. Furthermore,
Silver zeolite □Upstream and downstream of filled filter 3
]' A picture tube is connected to the first frame a□ degree measuring device 5.

1) To perform the detection using this device, the process gas is flowed into the Lyle housing 1 containing all iodine, and the process gas is detected using the heater 2'.
``'P's total should be 0.2 or more.In any condition, for a specified period of time, for example, silver zeolaotka ÷ water absorption is about to occur□
In case □ is 0, silver zegerite is o, 11 g/g If water is absorbed by adsorbent 1, after aeration for about 10 hours, Freon is introduced from Freon generator 4 together with carrier gas such as air. . After waiting for the introduction to stabilize, a part of the ventilation gas is introduced from the silver zeolite-filled filter side to the Freon concentration measuring device 5, and the concentration of L Freon is measured using the following formula. ! -6° 1□.

・□・, ..., f...ω As the freon concentration measuring device 5, a gas chromatograph with an ECD (electron capture detector) is suitable. 1. Next, the heating conditions for the processing gas will be explained using the relationship between water vapor pressure and temperature. Figure 3 shows the relationship between water pressure and temperature. Ps
= 1, ``'0.7, l 0.5th case is shown.For example, when the process is 3',,Oc, P'/Ps
If there was, the processing gas was 30 C% P/P
The water vapor pressure in the case of s 20.5 is '16 m m)i
Since (9) this'fe P / :l)s20, P8 which makes it less than 2 is 8'Q m m )(g or more.And □
, Pg"47' to make it 180m'mHg or more.
In other words, it is sufficient to heat the temperature so that the temperature rise ΔT is 17':C or more. In addition, if the processing gas is 3°C and the conditions are P/''Ps = 0.7 (maximum value of general ambient air in the power plant), the required temperature rise ΔT will be 23C or more when calculated in the same way, and other It can be calculated using the same procedure in the case of .

The minimum heater capacity to obtain this required temperature increase ΔTffi can be calculated using the following formula.

W (kJ/s, kW): 2.5X10-', Δ'['-F... River...
...(2) Here, W is the heater capacity, 0.92 Ck
J/m8c:] is the specific heat of air, and F is the flow rate of the processing gas.

Using equation (2), the ventilation gas condition is 300°P/
P s = 0.5 (W = 4.25X1 in case of D
0-3F'.

30C, P/Ps = 0.7 (W-(10) in case of D It becomes 5.75X10-3F.　　　　　　　　　　　　.

Therefore, using this method, 5. Heating the processing gas: then P/Ps −= o, 2. If it's afternoon, you can do it at 1. Therefore, it is now possible to detect leaks using freon from filters filled with Kinakatsu Mugin Zeolite, which has not been able to satisfy this condition in the past.

In the above example, it is possible to raise the temperature of the processing gas to
Although the Ps'i was reduced, the same effect could be obtained by installing a dehumidifier in the front stage. Alternatively, a gas flow path for reducing the humidity of the silver zeolite may be provided separately, and when it is necessary to detect leakage from the filter, ventilation may be carried out from this flow path, thereby reducing the humidity of the silver zeolite. . Also,
The haze of silver zeolite once dried is 0.1 t, g,
/g It takes at least 3 hours for the adsorbent to absorb water, so if you dry it in advance, you can detect leaks with two-on until water is absorbed, regardless of the properties of the ventilation gas. be able to. This school transfer process refers to flowing a gas of P/P, s = 0.2 or less, or drying using an oven or the like. In addition, it is usually commercially available.

(11) Since silver zeolite is dried at about 40 m (1 m),
If used as is, the first leak detection can be performed without any manual operation.

As a matter of fact, above, we talked about the case of water as a condensable gas on the flow side, but the same effect can be obtained with other organic gases such as oil, and it can also be used as a gas for leak detection. :te), I mentioned Leon's case, but CCt4
, CHC4a, etc. Similar effects can be obtained with other physically adsorbable gases.

〔Effect of the invention〕

As described above, the present invention enables the adsorption of silver zeolite, the detection of leaks in iodine removal materials, and the use of gases of all physically adsorbable substances, and has industrial effects. It is a big thing. .

[Brief explanation of drawings]

Figure 1 shows the water absorption of silver zeolite and impregnated carbon and the P of water.
/ P s, FIG. 2 is a flow diagram of an apparatus for carrying out an embodiment of the zeolite-filled filter glue detection method of the present invention, and FIG. 3 is a diagram showing the relationship between water vapor pressure and water vapor pressure. This is a diagram (12) showing the relationship between and temperature. ■...Iodine filter housing, 2...Heater, 3...Fugorta filled with silver zeolite, 4...Freon generator, and...Freon concentration measuring device. , agent Patent attorney Hiroshi Chisaki, male (1 other person) (13) Part I Figure 0 0204 0, li (1810,
Surprising water pressure (I's,)

Claims (1)

[Claims] 1. In a method for detecting leakage in an iodine removal filter filled with silver zeolite as an adsorbent, physical A method for detecting leaks in filters filled with silver zeolite, in which the gas of an adsorbent substance is aerated. □ 2. The condensable gas is water vapor, and the gas is fully vented while the adsorption amount of water condensed by the water vapor is maintained at 0.11 g or less per 1 g of the silver zeolite.Claim 1' A leak detection method for a filter filled with silver zeo. ' 3. The adsorption amount of the water is 90.1 per 1 g of the silver zeolite.
A leak detection method for a filter filled with secreted zeolite according to claim 2, wherein the state maintained at 1 g or less is obtained by aerating gas with a relative humidity of 20'% or less. 4. The gas with a relative humidity of 20% or less is provided at the front stage of the silver zeolite-filled filter. Here, W is the heater capacity (kW), and F is the amount of gas vented to the silver-zeolite-filled filter. The leak detection method for a filter filled with silver zeolite according to claim 3, which is obtained by heating with a heater having a capacity higher than that calculated by the flow rate (m3/h).