JPH08164331A - Reaction vessel for electron beam-irradiated gas treatment - Google Patents

Abstract

PURPOSE: To reduce the loss of an electron beam on the wall face of a reaction vessel without lowering the reaction efficiency of the entire reaction vessel by generating a magnetic field in the vessel to suppress the diffusion of the electron beam. CONSTITUTION: A magnetic field is generated in a reaction vessel 1 to suppress the diffusion of an electron beam. The necessary magnetic flux density is controlled to 10-10,000 gauss at the peripheral part of the electron beam. Although the various shapes of magnetic field are used, a magnetic field existing on the periphery of the electron beam and counterclockwise to the electron incident direction or a magnetic field parallel or antiparallel to the electron incident direction is exemplified. Incidentally, when about 12,5000m<3> N/h of the waste gas contg. about 200ppm NOx and kept at about 60 C us introduced into the horizontal reaction vessel 1 from its inlet 2 and irradiated with an electron beam of about 90mA in total with three electron accelerators 3, 4 and 5 each having about 800kV accelerating velocity, the loss of the beam on the entire wall face is reduced to about 10% when magnets 8 to 23 are set on each electron accelerator, and about 85% of NOx are removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction container for electron beam irradiation gas treatment, which has a window for transmitting an electron beam, and causes a chemical reaction by irradiating an internal gas through the window with the electron beam.

[0002]

2. Description of the Related Art An electron beam irradiation gas treatment method in which a gas in a reaction vessel is irradiated with an electron beam through a window attached to the reaction vessel to cause a chemical reaction in the gas has been put into practical use. However, with respect to the reaction vessel, although the device for adjusting the spread of the electron beam diffused in the gas has been devised, the spread itself of the electron beam has not been adjusted.

Further, in the scanning electron accelerator, it has been devised that the path of the electron deflected by scanning is bent by a magnetic field so that the electron vertically enters the window immediately before the electron enters the window. There is no attempt to suppress the scattering of the electron beam due to scattering when passing through a window, which is usually made of thin metal foil, and scattering by the gas in the reaction vessel.

[0004]

In the conventional method which does not suppress the diffusion of the electron beam in the reaction vessel, the diffused electrons collide with the wall surface of the reaction vessel and cause a chemical reaction, which is not effectively used and causes a loss. There was a problem of doing. On the other hand, in order to reduce the loss on such wall surface, if the reaction vessel is made large enough to include the reach of the electron beam,
There is a problem that the intensity of the electron beam is weak and a portion where the chemical reaction does not proceed sufficiently occurs, resulting in a decrease in overall reaction efficiency.

An object of the present invention is to provide a reaction container for electron beam irradiation gas treatment which reduces the loss of the electron beam on the wall surface of the reaction container and does not lower the reaction efficiency of the entire reaction container.

[0006]

In order to achieve the above object, in the present invention, a magnetic field is provided in the reaction container so as to suppress the diffusion of the electron beam. The required magnetic flux density is about 10 to 10000 gauss at the periphery of the electron beam bundle. There are various possible forms of the magnetic field, but there are magnetic fields in the peripheral portion of the electron beam bundle and in a counterclockwise direction when viewed from the incident direction of the electrons (FIGS. 3, 5, 7,
8), or a magnetic field (FIGS. 9 and 10) in a direction parallel or antiparallel to the incident direction of electrons. Among these, as a mode in which the magnetic field is present in the peripheral portion of the electron beam bundle and in the counterclockwise direction when viewed from the incident direction of the electrons, a plurality of permanent magnets and N poles are provided in the peripheral portion of the electron beam bundle. The south poles are arranged at intervals so as to face each other (FIGS. 3, 5, and 8). The permanent magnets may be arranged by any arrangement as long as the required magnetic flux density is satisfied and the passage of exhaust gas is not hindered. For example, the spacing between the permanent magnets in FIG. 5 is about 600 mm.
The magnetic flux density on the surface of the magnet was 1000 gauss. Further, as a mode of generating a magnetic field in a direction parallel to the electron incident direction, there is a system in which a direct current is passed through an electric wire spirally wound so as to bundle a beam bundle of electrons (FIG. 10).
Also in this method, any arrangement may be used as long as the required magnetic flux density is satisfied and the passage of exhaust gas is not hindered.
In order to obtain 100 gauss with the method of FIG. 10, the electric wire that carries a current of 1 A is 10,000 times per 1 m, or 10
It is necessary to wind the electric wire for passing the current of A 1000 times per 1 m. In this case, in particular, if a direct current flowing through an electric wire spirally wound so as to bundle the electron beam bundle is supplied to the electron beam generator, extra power for suppressing diffusion of the electron beam is unnecessary. become.

[0007]

When the electron beam is scattered by the gas in the window and reaction vessel, which are usually made of thin metal foil, the course of the electrons is deviated from the initial incident direction. Also, when secondary electrons are generated during scattering, they travel in a direction different from the incident direction of primary electrons. On the other hand, when there is a magnetic field in the electron's path, the Lorentz force can bend the electron's path without changing the speed of the electron and thus without losing the energy of the electron. Therefore, it is possible to prevent the electrons from deviating from the original incident direction and colliding with the wall surface of the reaction container by giving a magnetic field in an appropriate direction in the reaction container.

If there is a counterclockwise magnetic field as seen from the electron incident direction at the peripheral portion of the electron beam bundle, the electron incident direction is the x-axis, and the magnetic field direction at each point on the peripheral portion is the y-axis. If selected, the velocity component at which the electrons try to deviate from the original beam bundle will be in the positive z-axis direction if the coordinate system is the right-handed system. On the other hand, the component of the Lorentz force that the electron receives in the z-axis direction is −eBv _x, where v _x is the velocity of the electron in the x-axis direction (= incident direction), which is always negative. Here, e is the elementary charge and B is the magnetic flux density. Therefore, the Lorentz force acts so as to cancel the velocity in the positive direction of the z axis, which attempts to deviate from the beam bundle, and thereby,
The diffusion of electrons will be suppressed.

Such a magnetic field can be generated by arranging a plurality of permanent magnets at intervals along the periphery of the electron beam bundle so as to face the N pole and the S pole (FIGS. 5 and 8). it can.

Next, when there is a magnetic field parallel or antiparallel to the incident direction of the electrons, even if the velocity component of the electrons deviates from the incident direction, the velocity component does not cause the electrons to go straight, and the spiral. To exercise like a
Also in this case, the diffusion of electrons is suppressed. Then, such a magnetic field can be generated by a method (FIG. 10) of passing a direct current through an electric wire spirally wound so as to bundle a beam bundle of electrons.

The present invention will be described below with reference to examples.
The present invention is not limited to this.

[0012]

EXAMPLE A horizontally installed reaction vessel 1 shown in FIG. 1 containing 200 ppm of nitrogen oxides from an inlet 2 and having a temperature of 60 ° C.
Exhaust gas of 12,500 m ³ N / h, and 90 m in total by three electron accelerators 3 to 5 with an acceleration voltage of 800 kV
When the electron beam A was irradiated, 70% of nitrogen oxides were removed. In this case, the intensity distribution of the electron beam in the cross section of the reaction container is as shown in FIG. 2, and about 25% of the generated electron beam is lost on the wall surface of the reaction container.

Next, as shown in FIG. 3, one set of permanent magnets 6 to 7 for each accelerator was installed on the outer bottom of the reactor shown in FIG. 1 and inside the reactor. As indicated by the curved line with an arrow, the intensity is 2 in the counterclockwise direction toward the incident direction of the electron beam at the periphery of the electron beam bundle.
A magnetic field of 0-30 Gauss was generated. From the inlet of this reactor with a magnetic field, nitrogen oxide was included at 200 ppm, and the temperature was 60 °
A total of 90 mA with 3 electron accelerators with an accelerating voltage of 800 kV, leading to an exhaust gas of 12,500 m ³ N / h as C
75% of nitrogen oxides were removed by irradiating the electron beam. In this case, the intensity distribution of the electron beam in the cross section of the reaction vessel is as shown in FIG. 4, and the loss on the bottom surface of the reaction vessel is reduced by the magnetic field, and the loss on the entire wall surface is about 20%. .

Finally, in the same reaction vessel as shown in FIG. 1, a permanent magnet 8 is provided for each accelerator as shown in FIG.
As a result, as shown by a curved line with an arrow in the figure, 50 to 1000 in a counterclockwise direction toward the electron incident direction are installed inside the reactor.
A Gaussian magnetic field was created. From the inlet of this reactor with a magnetic field, 12,500 m ³ N / h of exhaust gas containing 200 ppm of nitrogen oxide and having a temperature of 60 ° C. was introduced, and an accelerating voltage was 80
When three electron accelerators of 0 kV were irradiated with an electron beam of 90 mA in total, 85% of nitrogen oxides were removed. In this case, the intensity distribution of the electron beam in the cross section of the reaction vessel is as shown in FIG. 6, and the loss at the bottom of the reaction vessel is reduced by the magnetic field, and the loss on the entire wall surface is about 10%. .

The loss on the wall surface of the reaction vessel (P ₃ %) is calculated as follows.

The power P ₀ of the electron beam output from the electron accelerator is distributed as follows.

P ₀ = P ₁ (loss in irradiation window) + P ₂ (power absorbed by gas in reaction vessel) + P ₃ (loss in wall surface of reaction vessel) Therefore, P ₃ (%) = P ₃ / P ₀ x100 = (P ₀ −P ₁ −P ₂ ) / P ₀ x100 P ₁ : The irradiation window consists of a thin metal foil and a cooling gas layer (air, helium or nitrogen), and when passing through each substance Regarding the loss, the actual measurement data has been released, and the loss at the irradiation window is calculated based on the published data.

P ₂ : When an electron beam is irradiated while the CTA film is stretched in the reaction container, the absorbance of the CTA film changes in proportion to the intensity of the irradiated electron beam. Therefore, the power (kW) of the electron beam absorbed in the gas at various points in the reaction vessel is calculated from the absorbance of the stretched CTA film, and integrated over the entire reaction vessel, the total gas in the reaction vessel is calculated. The total amount P ₂ (kW) of the power of the electron beam absorbed by the is calculated.

[0019]

According to the present invention, it is possible to provide a reaction container for electron beam irradiation gas treatment which reduces the loss of electron beam on the wall surface of the reaction container and improves the reaction efficiency of the entire reaction container.

[Brief description of drawings]

FIG. 1 is a schematic view of a horizontally-installed reaction container used in Examples.

FIG. 2 shows an intensity distribution of an electron beam in a cross section of a reaction container when the diffusion of the electron beam is not suppressed.

FIG. 3 shows generation of a magnetic field in a counterclockwise direction when viewed from the incident direction of an electron beam when one set of permanent magnets is installed on the outer bottom of a reaction container for each accelerator.

FIG. 4 shows an electron beam intensity distribution in a cross section of the reaction vessel by the magnetic field shown in FIG.

FIG. 5 shows a state in which a plurality of permanent magnets are installed at intervals along the entire periphery of the electron beam bundle inside the reaction vessel for each accelerator so that the N pole and the S pole face each other.

FIG. 6 shows an electron beam intensity distribution in a cross section of a reaction container, in which a plurality of permanent magnets are installed at all peripheral portions of the electron beam bundle shown in FIG.

FIG. 7 shows a state in which the magnetic field in the reaction vessel is at the peripheral portion of the electron beam bundle and is oriented counterclockwise as seen from the electron incident direction.

FIG. 8 shows a plurality of permanent magnets at the periphery of the electron beam bundle,
By arranging the N pole and the S pole with a space so as to face each other, it is shown that the magnetic field exists at the peripheral portion of the electron beam bundle and occurs in the counterclockwise direction when viewed from the incident direction of the electrons.

FIG. 9 shows a state in which the magnetic field in the reaction vessel is oriented parallel to the electron incident direction.

FIG. 10 shows a state in which a magnetic field is generated in a direction parallel to the incident direction of electrons by applying a direct current to an electric wire spirally wound so as to bundle a beam bundle of electrons.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Nanba 1233 Watanuki-cho, Takasaki-shi, Gunma Japan Atomic Energy Research Institute Takasaki Research Institute (72) Inventor Masa Tanaka, Kitakanyama, Otaka-cho, Midori-ku, Nagoya-shi, Aichi Prefecture No. 1 Chubu Electric Power Co., Inc. Power Technology Research Institute (72) Inventor Yoshimi Ogura No. 20 Kitakaseyama, Otaka-cho, Midori-ku, Nagoya-shi, Aichi No. 1 Chubu Electric Power Co. Power Technology Research Center (72) Inventor Yoshitaka Doi Tokyo 11-11 Haneda-Asahicho, Ota-ku Inside EBARA CORPORATION (72) Inventor Masahiro Izutsu 11-1 Haneda-Asahicho, Ota-ku, Tokyo Inside EBARA CORPORATION

Claims (7)

[Claims] 1. A reaction vessel having a window for transmitting an electron beam and irradiating an internal gas through the window with the electron beam to cause a chemical reaction, which has a magnetic field for suppressing diffusion of the electron beam. A reaction container for treating an electron beam irradiation gas, which is characterized in that: 2. The reaction according to claim 1, wherein the magnetic field in the reaction vessel is at the peripheral portion of the electron beam bundle and is oriented counterclockwise as viewed from the electron incident direction. container. 3. A magnetic field in the peripheral portion of the electron beam bundle and in a counterclockwise direction when viewed from the electron incident direction has a plurality of permanent magnets N and S poles in the peripheral portion of the electron beam bundle. 3. The reaction vessel according to claim 2, wherein the reaction vessels are arranged so as to face each other with a space therebetween. 4. The reaction container according to claim 1, wherein the magnetic field in the reaction container is in a direction parallel or antiparallel to the incident direction of electrons. 5. A magnetic field in a direction parallel to the incident direction of electrons,
It is characterized by being generated by a direct current flowing through an electric wire spirally wound so as to bundle a beam bundle of electrons.
The reaction container according to claim 4. 6. The reaction container according to claim 5, wherein a direct current flowing through an electric wire spirally wound so as to bundle a beam bundle of electrons is supplied to the electron beam generator. 7. The reaction container according to claim 1, wherein the strength of the magnetic field is at least 10 gauss at the peripheral portion of the electron beam bundle.