JPH0672703A - Method and device for regenerating gas for iodine gas laser - Google Patents

Abstract

PURPOSE:To reduce the consumption of expensive gaseous helium by regenerating used gas discharged from a chemically excited iodine gas laser unit so that, the gas can be reused. CONSTITUTION:Used gas contg. O2, Cl2, and I2 in He is brought into contact with an alkali substance preferably in a powder fluidized bed reactor to remove the Cl2 and I2 by absorption, H2 is then introduced into the reactor and allowed to react with the O2 in the presence of a catalyst to convert the O2, into H2O and this H2O is removed by condensation or adsorption.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for reusing a gas used for chemically excited iodine laser oscillation so that it can be reused.

[0002]

2. Description of the Related Art A chemically excited iodine laser generates oxygen in an excited state by blowing chlorine into an alkaline hydrogen peroxide solution, and excites iodine by bringing the excited oxygen into contact with iodine gas in helium. It extracts the constant wavelength light energy generated when iodine in the excited state returns to the ground state. The iodine laser has an advantage that it is suitable for transmission through a fiber cable in the near infrared region (1.315 μm), and it is possible to increase the output. Therefore, the iodine laser is being developed as a promising laser technology.

H ₂ O ₂ +2 NaOH + Cl ₂ → O ₂ ( ¹ Δ)
+ 2H ₂ O + 2NaCl O ₂ ( ¹ Δ) + I (P _3/2 ) → O ₂ ( ³ Σ) + I (P _1/2 ) I (P _1/2 ) → I (P _3/2 ) +1.315 μm Is a flowchart showing this system configuration.

Most of the chlorine blown into the excited oxygen generator becomes NaCl by the above reaction, but some of it enters the gas. Therefore, the gas discharged from the laser oscillator has a composition in which helium is mixed with chlorine, iodine, and oxygen. Excited oxygen mixed with iodine needs to occupy at least about 20% of total oxygen.

For this reason, conventionally, the gas used for the iodine laser oscillation was released and the fresh gas had to be supplied. However, since helium gas is expensive, it is desirable to remove harmful substances from this used laser gas to recover useful helium gas (purity 99% or more).

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and apparatus for reusably regenerating the gas used for lasing in response to the above needs in chemically excited iodine gas laser technology. Especially.

[0007]

A method for regenerating a gas for an iodine gas laser according to the present invention is a method for reusably reusing a gas used for chemically excited iodine laser oscillation, wherein chlorine in helium, Generated water by contacting a used gas containing iodine and oxygen with an alkaline substance to absorb and remove chlorine and iodine, and adding hydrogen in an amount approximately equivalent to oxygen in the gas to react in the presence of a catalyst. Is removed from the gas by condensation or adsorption.

Although it is possible to carry out the contact with the alkaline substance and the addition of hydrogen at the same time, generally, in order to avoid the deterioration of the catalyst by chlorine and iodine, the contact with the alkaline substance is first carried out to remove chlorine and iodine. After that, it is preferable to remove oxygen by hydrogenation.

Alkaline substances include NaOH and KO
It is suitable to use one or two selected from H, CaO, Ca (OH) ₂ and Mg (OH) ₂ . Especially, from the viewpoint of cost and easy handling, Ca (OH) ₂
Is advantageous.

As a mode of contacting the used gas and the alkaline substance, wet absorption using a solution or dispersion of the alkaline substance is convenient, but when the laser oscillation is performed under reduced pressure, the dry type is used. Operation is desirable.

In dry operation, it is preferred that the alkaline material is contacted by the spent gas to form a powder fluidized bed. In this case, it is preferable to heat the powder fluidized bed when water is generated and condensation of the powder may cause aggregation of the powder. Alternatively,
A fixed bed adsorption tower can also be used.

In order to prevent an explosion caused by adding hydrogen to a gas containing oxygen, hydrogen is added continuously or intermittently in accordance with the consumption due to the reaction with oxygen. While avoiding the quantity entering the explosion limit,
It is better to react both.

The apparatus of the present invention for carrying out the above method for regenerating a gas for an iodine gas laser is an apparatus for reusing a gas used for chemically excited iodine laser oscillation so that it can be reused. As shown, a powder fluidized bed reaction for absorbing and removing chlorine and iodine in the gas by forming a powder fluidized bed of an alkaline substance (6) with a used gas containing chlorine, iodine and oxygen mixed in helium. (1), cyclone (2) and / or dust removal means consisting of filter (3), oxidation catalyst (7) is filled, and fixed with one or more hydrogen inlets (41) provided A bed reactor (4) and a water separation means (5) for condensing or adsorbing water in the gas are connected to each other, and means for circulating the gas (not shown) is added to these devices.

This apparatus is located at the position * 1 in FIG. 1, that is, between the oscillator and the vacuum pump, and the regenerated gas is sent to the excitation O ₂ generator and the mixer by a circulation blower (not shown). Is the normal usage, but it can also be placed at the * 2 position, that is, behind the vacuum pump.

Assuming continuous operation for a long time, the powder fluidized bed reactor is supplied with an alkaline substance such as Ca (OH) ₂ from one side and discharges a reaction product with chlorine or iodine from the other side. It is desirable to use one having a structure that allows it.

[0016]

OPERATION Referring to the apparatus shown in FIG. 2, the used gas containing chlorine, iodine and oxygen in helium first enters the powder fluidized bed reactor (1). When Ca (OH) ₂ is used as the alkaline substance, chlorine and iodine in it are used in the next reaction 2Ca (OH) ₂ + 2Cl ₂ → CaCl ₂ + Ca (Cl
O) ₂ + 2H ₂ O 2Ca (OH) ₂ + 2I ₂ → CaI ₂ + Ca (IO) ₂ +2
It is fixed and removed by H ₂ O.

Since the reaction is a dry heterogeneous reaction, it is desirable to have a large contact area, and it is necessary to prevent the reaction product from covering the powder surface and hindering the progress of the reaction. For that purpose, it is expected that the alkaline substance will be used as a fine powder, sufficient contact mixing will be achieved by the powder fluidized bed, and that the surface will be renewed due to collision between the powders.

Since it is inevitable that some fine powder escapes from the powder fluidized bed, it is recovered and removed by the cyclone (2). In addition, the gas is sent to the fixed bed reactor through the filter (3). The fixed bed reactor (4) is filled with catalyst particles such as an alumina-supported noble metal catalyst, and is burned by adding approximately equivalent amount of hydrogen to oxygen remaining in helium gas from which chlorine and iodine are removed. By changing the oxygen into water.
It is desirable to operate at the lowest temperature possible, with cooling if necessary to remove the heat generated by the reaction.

In order to avoid the explosion, in addition to the above-described method of successively adding hydrogen, by circulating a part of the outlet gas of the fixed bed reactor to the inlet, the concentration of oxygen and hydrogen in the reactor is increased. A method of lowering the

The helium gas containing oxygen in place of water is then condensed or adsorbed to remove water. Adsorption is easy with a small device, but condensation with cooling is advantageous for a large device. In this case, it goes without saying that cooling energy should be saved by heat exchange between the outlet gas and the inlet gas.

[0021]

Example: He gas with O _{2 of} 20% by volume and Cl
₂ : 0.1% and I ₂ : 0.04% were added to prepare a simulated used gas for laser.

7.4 g of Ca (OH) ₂ fine powder was placed in a powder fluidized bed reactor having a ceramic bottom plate on the bottom of a cylinder, and the above gas was introduced from the bottom at a rate of 1.5 liter / min. And a fluidized bed was formed to absorb and remove Cl ₂ and I ₂ .

The gas passes through a quartz filter,
30 g of catalyst in which Pt: 0.5% is supported on alumina particles
Was introduced from the bottom into a vertical fixed bed reactor filled with.
The catalyst bed has a packing height of 0 from the bottom,
Hydrogen inlets are provided at positions corresponding to ⅓ and ⅔, and an equivalent amount of H ₂ to O _{2 in} the gas, that is, 0.6 liter / min, is ⅓ from these inlets. Introduced one by one.

The gas discharged from the fixed bed reactor was passed through a drier filled with phosphorus pentoxide to remove the water content therein.

Impurities in the helium gas thus regenerated are O ₂ : 0.05% and Cl ₂ : 0.0, respectively.
02% or less, I ₂ : 0.002% or less, the dew point of the gas was −20 ° C. or less, and the purity was greater than 99% He.

[0026]

According to the present invention, the used gas discharged from the chemically excited iodine laser device is almost completely free of Cl.
_{It is possible} to remove ₂ , I ₂ and O ₂ and recover He gas having a purity of more than 99%.

If this recovered gas is reused in the laser device, it is not necessary to constantly supply fresh gas, and expensive helium can be saved. Therefore, the operating cost of the iodine gas laser device can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a gas-related system flow of a chemically excited iodine gas laser.

FIG. 2 is a flowchart showing a configuration of a gas regenerating apparatus for iodine gas laser according to the present invention.

[Explanation of Codes] 1 powder fluidized bed reactor 2 cyclone 3 filter 4 fixed bed reactor 5 water separation means 6 alkaline substance 7 oxidation catalyst

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsutomu Toida 2205 Narita-cho, Oarai-cho, Higashi-Ibaraki-gun, Ibaraki Pref. Inside the Oarai Nuclear Technology Development Center, JGC Corporation

Claims (6)

[Claims] 1. A method of reusably reusing a gas used for chemically excited iodine laser oscillation, which comprises contacting a used gas in which chlorine, iodine and oxygen are mixed in helium with an alkaline substance to chlorine. And a gas for an iodine gas laser, which absorbs and removes iodine, adds hydrogen in an amount approximately equivalent to oxygen in the gas, reacts in the presence of a catalyst, and removes generated water from the gas by condensation or adsorption. How to play. 2. NaOH, KO as the alkaline substance
The regeneration method according to claim 1, wherein one or more selected from H, CaO, Ca (OH) ₂ and Mg (OH) ₂ is used. 3. The regeneration method according to claim 1, wherein the alkaline substance is brought into contact with the used gas as a powder fluidized bed. 4. The regeneration method according to claim 3, which is carried out while heating the powder fluidized bed to prevent aggregation of the powder due to condensation of water. 5. The method according to claim 1, wherein hydrogen is added continuously or intermittently in accordance with the consumption due to the reaction with oxygen, while avoiding that the amounts of hydrogen and oxygen in the gas enter the explosion limit. How to play. 6. A device for reusably reusing a gas used for chemically excited iodine laser oscillation, wherein a powder of an alkaline substance (6) is produced by a used gas containing chlorine, iodine and oxygen mixed in helium. Dust removal means comprising a powder fluidized bed reactor (1) for forming a body fluidized bed to absorb and remove chlorine and iodine in gas, a cyclone (2) and / or a filter (3), an oxidation catalyst (7) ), And one or more hydrogen inlets (41)
An iodine gas laser comprising a fixed bed reactor (4) and a water separation means (5) for condensing or adsorbing water in a gas are connected, and a means for circulating the gas is added to these devices. Gas regeneration device.