JP2007007604A - Electron beam irradiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electron beam irradiator disassemblable at low cost and high efficiency, even if a substance contained in gas is a gaseous compound of malodor substance like highly concentrated hydrogen sulfide. <P>SOLUTION: This electron irradiator emits electron beam 22 through an irradiation window 21 comprising titanium foil 21a, to decompose a malodor substance like hydrogen sulfide in the gas 10 passing through a gas treatment chamber body 9c. In the gas treatment chamber body 9c, two baffle plates 31, 32 are raised with a given space right under the irradiation window 21 toward the gas flow direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electron beam irradiation apparatus.

  For odorous substances such as high-concentration hydrogen sulfide generated from sewage treatment plants and industrial wastewater treatment plants, treatment by a biological deodorization treatment method has been generally used. FIG. 7 shows an apparatus layout of a general processing flow for performing such a biological deodorization processing method. In the figure, reference numeral 1 denotes a packed tower type biological deodorization apparatus filled with a sponge or a ceramic carrier in which microorganisms live inside or on the surface. The biological deodorization apparatus 1 contains an odorous substance such as hydrogen sulfide. Gas 2 can be supplied, and water 3 for spraying water can be sprayed from the upper part of the tower, or caustic soda 4 can be supplied. 5 is an eliminator for removing the entrained water from the gas 6 decomposed and deodorized and sent from the biological deodorizing apparatus 1, and 7 is the gas 6 from which water has been removed by the eliminator 5. A fan 8 is an activated carbon adsorption tower for removing odorous substances that could not be completely decomposed by the biological deodorizing apparatus 1, and the deodorized gas 6 'is discharged into the atmosphere.

  When the gas 2 is passed through the biological deodorization apparatus 1, odorous substances such as hydrogen sulfide in the gas 2 are dissolved, absorbed, or adsorbed on the surface of the carrier in water adhering to the surface of the carrier. The odorous substance trapped on the carrier is oxidized and decomposed by microorganisms living on the carrier to become an oxidation product and is not brominated. Sprinkling of water 3 for watering is performed intermittently or continuously from the top of the tower of the biological deodorizing apparatus 1 in order to discharge oxidation products and supply water necessary for the growth and maintenance of microorganisms. Further, in order to maintain a constant pH so that the water 3 for watering can be recycled, the caustic soda 4 is supplied to the biological deodorizing apparatus 1 for neutralization when necessary.

  On the other hand, the electron beam irradiation method is generally used for curing, sterilization, etc., but in the environmental field such as exhaust gas treatment, it is used for decomposition treatment of air pollutants such as nitrogen oxides and sulfur oxides. It has only been put into practical use and has not been applied to the decomposition treatment of odorous substances such as hydrogen sulfide.

  An example of the arrangement of the conventional electron beam irradiation apparatus is shown in FIGS. 8 to 10, and the electron beam irradiation apparatus shown in FIGS. 8 to 10 is a non-scanning type (generally an acceleration voltage of 300 kV or less). (Applied to the above)) (which irradiates an object to be processed straight with an electron beam drawn out from the filament by increasing the filament width). In the following description, the direction in which the gas 10, 10 'advances straight as indicated by the straight line B in FIG. 8 is referred to as the "direction along the gas flow direction".

  8 to 10, reference numeral 9 denotes a gas processing chamber in which a gas 10 to be processed is introduced and processed, and 11 denotes a rectangular box-shaped cross section arranged on the gas processing chamber 9 so that the inside is kept in a vacuum. The planar shape is a vacuum chamber with a circular box shape. The gas processing chamber 9 includes a narrow gas inlet side duct-shaped portion 9a and a gas outlet-side duct-shaped portion 9b, and a wide-shaped gas processing chamber main body 9c located between the duct-shaped portions 9a and 9b. (See FIG. 10).

  The duct-shaped portions 9a and 9b are formed in a shape that widens from the middle so as to be connected to the gas processing chamber main body 9c on the gas processing chamber main body 9c side, and the height of the duct-shaped portions 9a and 9b is It is formed lower than the height of 9c. Further, from the duct-shaped portion 9a side to the gas processing chamber main body 9c, they are arranged at regular intervals in the width direction in the duct-shaped portion 9a, and in the gas processing chamber main body 9c, rectification is performed so that the adjacent width intervals gradually increase. A plate 12 is provided.

  A bottomed cylindrical member 13 that is a high-pressure introducing portion is accommodated in the upper center portion in the vacuum chamber 11. In the vicinity of the center portion in the bottomed cylindrical member 13, the upper end side protrudes to the outside and the lower end side is a bottomed cylindrical member. Two high-voltage introduction rods 14 that hang down to the vicinity of the bottom of the member 13 are arranged. The high voltage introduction rod 14 is connected to a filament power source 15a which is an AC power source or a DC power source and an acceleration power source 15b which is a DC power source. The acceleration power source 15b is connected to a titanium foil 21a of the irradiation window 21.

  Furthermore, a hollow shield electrode 17 having an arcuate portion at the outer end is provided at the lower ends of the two high voltage introduction rods 14 via high voltage conductive rods 16a and 16b. Thus, the high voltage conductive rod 16 a is connected to the shield electrode 17 to take a potential, and the high voltage conductive rod 16 b is insulated from the shield electrode 17. In FIG. 8, the filament power supply 15a is an AC power supply.

  Three sets of wide tungsten filaments 18 extending in the width direction of the vacuum chamber 11 and arranged at predetermined intervals in the direction along the gas flow direction are attached to the lower end of the rod-shaped portion of the high voltage conducting rod 16. ing. Further, the lower surface of the shield electrode 17 is slightly wider than the width of the tungsten filament 18 (see FIG. 9), and slightly wider than the length of the three sets of tungsten filaments 18 in the direction along the gas flow direction. A hole portion 17a is formed, and a mesh-like acceleration electrode 19 is provided in the hole portion 17a so as to block the hole portion 17a and contact the edge portion of the hole portion 17a. The reason why the acceleration electrode 19 is meshed is to allow electrons to pass through the mesh opening.

At the boundary between the bottom of the vacuum chamber 11 and the upper part of the gas processing chamber main body 9c in the gas processing chamber 9, the hole 17a formed in the shield electrode 17 is substantially the same in width and length in the direction along the gas flow direction. 20 is formed so as to be positioned almost directly below the hole 17a. The hole 20 is provided with an irradiation window 21 including a titanium foil 21a as if the hole 20 was closed. The titanium foil 21a can function as a ground electrode.
In the figure, 22 is an electron beam irradiated from the acceleration electrode 19 toward the irradiation window 21, and 23 is a plurality of support members that are fixed to the bottom surface of the bottomed cylindrical member 13 and support the shield electrode 17.

  In the electron beam irradiation apparatus shown in FIGS. 8 to 10, the gas 10 to be processed is introduced into the duct-like portion 9a of the gas processing chamber 9, rectified by the rectifying plate 12, and fed into the gas processing chamber main body 9c. Thus, the gas is dispersed in the gas processing chamber main body 9c as shown by the hatched lines in FIG.

  Thus, when a voltage of about 30 to 40 V is applied from the filament power supply 15a to the tungsten filament 18 through the high voltage introducing rod 14 and the high voltage conducting rods 16a and 16b, thermoelectrons are generated from the tungsten filament 18. The thermoelectrons generated in the tungsten filament 18 are accelerated by a high electric field generated between the acceleration electrode 19 and the titanium foil 21a by a high voltage of about 150 kV applied from the acceleration power supply 15b. As a result, the acceleration electrode 19 is accelerated. A high-speed electron beam 22 is irradiated toward the irradiation window 21, and the electron beam 22 transmitted through the irradiation window 21 contacts the gas 10 flowing through the gas processing chamber 9 in the gas processing chamber body 9c.

  For this reason, gas compounds such as odorous substances in the gas 10 are decomposed by the electron beam 22, and the gas 10 ′ that has been purified by the decomposition processing of the gas compound is removed from the duct-like portion 9 b on the downstream side to the outside of the gas processing chamber 9. Discharged downstream. In the gas processing chamber 9, the gases 10 and 10 ′ go straight as shown by a straight line B in FIG. 8 in a side view.

  As the electron beam irradiation method, in addition to the non-scanning type, there is a so-called scanning type (generally applied to an apparatus having an acceleration voltage of 300 kV or higher), which is shown in FIG. An apparatus applied to this scanning electron beam irradiation method is a vacuum chamber 11 disposed above a gas processing chamber 9, a filament power source 15a, an acceleration power source 15b, a tungsten filament 18, a mesh-like acceleration electrode 19, and a titanium foil. Although the point which provided the irradiation window 21 provided with 21a is the same as the non-scanning type | mold of FIGS. 8-10, between the acceleration electrode 19 and the irradiation window 21, an upper part is a narrow neck shape, a height direction A casing 24 that opens from the middle part downward in the direction along the gas flow direction is disposed, and a scan coil 25 (referred to as a deflection coil) is formed on the narrow neck portion of the casing 24 to generate a magnetic field. This is different from the non-scanning type in that the electron beam 22 is scanned by widening the distribution width by providing a coil for deflecting the line 22 and changing the direction.

  Also in the electron beam irradiation apparatus shown in FIG. 11, the gas 10 to be processed is introduced into the gas processing chamber 9. Further, when a voltage is applied to the tungsten filament 18 from the filament power supply 15a, thermoelectrons are generated from the tungsten filament 18, and the generated thermoelectrons are accelerated by the high voltage applied from the acceleration power supply 15b to the acceleration electrode 19 and the titanium foil. 21a is accelerated by a high electric field generated between them. As a result, the high-speed electron beam 22 is irradiated from the acceleration electrode 19 toward the irradiation window 21, and the electron beam 22 transmitted through the irradiation window 21 comes into contact with the gas 10 flowing through the gas processing chamber 9.

  For this reason, gaseous compounds such as odorous substances in the gas 10 are decomposed by the electron beam 22, and the gas 10 ′, which has been purified by the decomposition of the gaseous compounds, is discharged out of the gas processing chamber 9 toward the downstream side. The When the electron beam 22 travels from the acceleration electrode 19 to the irradiation window 21, the electron beam 22 is deflected by the magnetic field generated by the scan coil 25, changes its direction, and the distribution width widens toward the irradiation window 21.

  In the electron beam irradiation apparatus, the gas 10 is in the reaction part (in the case of the non-scanning type, the gas processing chamber body 9c, and in the case of the scanning type, the lower part of the irradiation window 21 of the gas processing chamber 9). The portion passes through the gas processing chamber 9 straight.

  For odorous substance treatment, there is a discharge plasma method as a technique similar to the electron beam irradiation method. Thus, the difference between the electron beam irradiation method and the discharge plasma method is as follows. That is, as described above, the electron beam irradiation method mainly has an action (direct action) in which an electron beam, which is a kind of radiation, is generated from a tungsten filament and the accelerated electrons collide with an odorous substance and is directly decomposed. In addition, it also has the effect of indirectly decomposing gaseous compounds such as odorous substances by generating radicals and the like by secondary excitation and ionization of atmospheric components (oxygen, moisture, etc.).

  On the other hand, the discharge plasma method creates a non-equilibrium plasma state (high electron energy, low ion and molecular energy state) by placing the discharge electrode in an odor substance, and excites atmospheric components (oxygen, moisture, etc.) The main action is to ionize and generate radicals, etc., to indirectly decompose odorous substances (indirect action), and the electron energy increases depending on the plasma state, but the contribution of direct action to odorous substances is higher than that of electron beam irradiation. Are considered small.

The direct action by the electron beam irradiation method is represented by [Chemical Formula 1], and the indirect action by the discharge plasma method is represented by [Chemical Formula 2].
[Chemical 1]
AB + e → A + B + e
C + e → C ^* + e
AB + C ^* → A ⁺ + B ⁻ + C ⁺ + e
AB + hν → A + B
[Chemical 2]
H ₂ O → H ₂ O ^*
H ₂ O ^* → H · + · OH
O ₂ → O ₂ ^*
O ₂ ^* → O ・ + ・ O
O ₂ + O · → O ₃
Here, in [Chemical Formula 1] and [Chemical Formula 2], for example, AB is H ₂ S, A is H, B is SH, C is H ₂ S, H ₂ O, O _2, etc., e is an electron, ^* Represents excitation, hν represents bremsstrahlung, and • represents a radical.

As prior art documents for treating exhaust gas, there are Patent Documents 1, 2, and 3, for example. In Patent Document 1, in order to increase the production efficiency of ammonium and ammonium sulfate by NO _X and SO _X treatment with an electron beam, a filler (Al, Ti, C, Be, etc.) is installed in the reactor with the electron beam, The production amount is increased to about 1.4 times, and a filler is placed in the reaction part to increase the production efficiency of the reaction product.

In Patent Document 2, in NO _X and SO _X treatment with an electron beam, a reflecting surface such as stainless steel is installed in the pipe and backscattered to improve the reaction efficiency with electrons. To improve the efficiency of decomposition treatment.

In Patent Document 3, the electron beam is focused from the cathode to the anode, the incident window is set to 1 mmφ, and the exhaust gas from the boiler is directly irradiated with the electron beam without disposing the thin film, and decomposition is performed. It is designed to eliminate the generation of lines, and by not providing a thin film, energy loss due to the thin film is eliminated, and loss of electron energy is reduced to improve decomposition efficiency.
JP-A-8-257352 JP-A-8-19202026 Japanese Patent Laid-Open No. 2003-4900

  However, in the biological deodorization treatment method for high-concentration hydrogen sulfide by the apparatus of FIG. 7, the decomposition treatment effect is large, but since it is mainly biological treatment, its maintenance is difficult, and the initial cost and running cost are high. There was a drawback.

  On the other hand, when a comparative decomposition treatment experiment was conducted in which high-concentration hydrogen sulfide was decomposed and compared by the electron beam irradiation method and the discharge plasma method, the discharge plasma method was about twice as much to obtain the same decomposition treatment effect. It required input energy. For this reason, it has been found that the discharge plasma method is more expensive than the electron beam irradiation method in terms of cost.

  Incidentally, the contact reaction between the odorous substance and the electron beam 22 in the electron beam irradiation apparatus shown in FIGS. 8 to 10 and 11 is performed in the gas processing chamber main body 9c which is a reaction part. However, generally, in the gas processing chamber main body 9c, the energy of the electron beam 22 irradiated from the upper part attenuates as the irradiation distance increases.

  For example, in the electron beam irradiation apparatus shown in FIGS. 8 to 10, when the electron beam 22 irradiated from the mesh-like acceleration electrode 19 is 150 keV, the breakdown is titanium foil 21 a (thickness 12) forming the irradiation window 21. .5 μm) is 137.3 keV due to absorption of itself and 97.0 keV due to attenuation at the lower part of the bottom surface of the titanium foil 21a, resulting in an energy loss of about 35%. Therefore, the energy (electron beam) of the electron beam 22 in the gas processing chamber body 9c is reduced. It can be seen that (energy) decreases from the upper part of the gas processing chamber body 9c (the lower surface of the titanium foil 21a of the irradiation window 21) to the lower part (see FIG. 12 and energy loss calculation described later).

  For this reason, in the conventional structure in which the gas 10 passes straight through the gas processing chamber 9, a gas containing an odorous substance (original odor gas) flows to the lower part of the gas processing chamber main body 9c having a low energy distribution, In this part, the reaction efficiency with the odor substance is low, and in particular, in the treatment of a high concentration odor substance, the decomposition treatment efficiency is low.

  In order to improve the decomposition efficiency of the odorous substance in the gas 10, the bottom surface 9 ′ (see FIG. 8) itself of the gas processing chamber body 9c is brought close to the surface of the titanium foil 21a below the irradiation window 21 (irradiation window 21). It is also possible to reduce the height dimension of the gas processing chamber main body 9c from the bottom of the gas processing chamber 9c. In this case, however, the bottom surface 9 'of the gas processing chamber main body 9c receives higher energy of the electron beam 22, and the Since the impact of the increase will be great, a separate cooling facility such as water cooling will be required.

  In general, although cooling of the bottom surface 9 'of the gas processing chamber main body 9c is considered by heat exchange with gas, the size of the gas processing chamber main body 9c is so high that it only receives energy of 60 keV or less. (See FIG. 12 and the energy loss calculation sheet described later). The reason why the heat load received by the gas processing chamber body 9c is up to 60 keV is that the gas processing chamber 9 can be used without any cooling in consideration of the cost of the gas processing chamber 9 and the like.

It will be described that the energy of the electron beam 22 of the gas processing chamber body 9c decreases as it goes down from the upper part of the gas processing chamber body 9c (the lower surface of the titanium foil 21a of the irradiation window 21).
For example, the thickness t of the titanium foil 21a of the irradiation window 21 is 12.5 μm, the chamber height H1 from the bottom surface of the titanium foil 21a of the gas processing chamber body 9c to the bottom surface 9 ′ of the gas processing chamber body 9c is 170 mm, and the titanium foil 21a When the energy Eo of the electron beam 22 on the upper surface is 150 keV (0.15 Mev) (see FIG. 12), the electron beam energy Et after passing through the titanium foil 21a is as follows.

That is, from the graph of FIG. 13, when the electron beam energy is 0.15 MeV, the stopping power (MeVcm ² / g) of the titanium foil 21 a is about 2.259 MeV · cm ² / g. Further, since the density of titanium is 4.51 g / cm ³ , the mass Wt per unit area of the titanium foil 21a when the thickness t is 12.5 μm is Wt = 4.51 g / cm ³ × 12.5. × 10 ⁻⁴ cm = 5.64 × 10 ⁻³ g / cm ² , so that the energy loss when passing through the titanium foil 21a is Eloss. a ^{t = 2.259MeV · cm 2 /g×5.64×10 -3} g / cm 2 = 12.7keV. Therefore, the electron beam energy Et after passing through the titanium foil 21a is 150 keV-12.7 keV = 137.3 keV.

Stopping power is the stopping power. Stopping power is the energy lost per unit length in a substance. The unit is MeV / cm. In this calculation, it is divided by the density ρ of the substance. Mass stopping power (MeV · cm ² / g) is used.

  Since the electron beam energy Et on the lower surface of the titanium foil 21a is 137.3 keV, the electron beam energy Ea in the gas (air) at the position a 20 mm below the lower surface of the titanium foil 21a is as follows.

That is, from the graph of FIG. 14, when the electron beam energy Et is 137.3 keV, the stopping power of air (MeVcm ² / g) is about 3.0 MeV · cm ² / g. Moreover, since the density of the air is 1.3 × 10 ⁻³ g / cm ³ , the mass Wa per unit area of the air at the position “a” having an air layer height of 20 mm is Wa = 1.3 × 10 ⁻³ g. / Cm ³ × 2 cm = 2.6 × 10 ⁻³ g / cm ² , and thus the energy loss of the electron beam 22 when descending to the position a 20 mm below the lower surface of the titanium foil 21a is Eloss. a = 3.0 MeV · cm ² /g×2.6×10 ⁻³ g / cm ² = 7.8 keV. Accordingly, the electron beam energy Et = 137.3 keV−7.8 keV = 129.5 keV at a position 20 mm below the lower surface of the titanium foil 21a.

Since the electron beam energy Ea at the position a is 129.5 keV, the electron beam energy Eb in the gas at the position b 20 mm below the position a is calculated in the same manner as described above and is as follows.
That is, from the graph of FIG. 14, when the electron beam energy Ea is 129.5 keV, the stopping power of air (MeVcm ² / g) is about 3.05 MeV · cm ² / g. Moreover, since the density of the air is 1.3 × 10 ⁻³ g / cm ³ , the mass Wb per unit area of the air at the position b where the air layer height is 20 mm is Wb = 1.3 × 10 ⁻³ g. / Cm ³ × 2 cm = 2.6 × 10 ⁻³ g / cm. Therefore, the energy loss of the electron beam 22 when descending from the position a to the position b 20 mm below is Eloss. b = 3.05 MeV · cm ² /g×2.6×10 ⁻³ g / cm ² = 7.9 keV. Accordingly, the electron beam energy Eb = 129.5 keV−7.9 keV = 121.6 keV at a position b 40 mm below the lower surface of the titanium foil 21a.

  In the same manner, the electron beam energy Ec, Ed, Ee, Ef, Eg, Eh at the positions c, d, e, f, g, and h at each position 20 mm below, and the gas treatment 10 mm below the position h, respectively. The electron beam energy Ei at the bottom surface 9 'of the chamber 9 is as follows (the calculation formula is omitted).

  That is, the electron beam energy Ec at a position c 60 mm below the lower surface of the titanium foil 21a is Ec = 113.5 keV, and the electron beam energy Ed at a position d 80 mm below the lower surface of the titanium foil 21a is Ed = 105.3 keV. The electron beam energy Ee at a position e 100 mm below the lower surface of 21a is Ec = 97.0 keV, the electron beam energy Ef at a position f 120 mm below the lower surface of the titanium foil 21a is Ef = 87.4 keV, and 140 mm from the lower surface of the titanium foil 21a. The electron beam energy Eg at the lower position g is Eg = 77.0 keV, the electron beam energy Eh at the position h 160 mm below the lower surface of the titanium foil 21a is Eh = 65.5 keV, and the position i 170 mm below the lower surface of the titanium foil 21a. (Bottom of gas processing chamber 9 Electron beam energy Ei in ') is Ei = 59.1keV.

  Thus, it is clear from the above calculation results that in the electron beam irradiation apparatus, the electron beam energy attenuates as the irradiation distance increases. Also, in the case of Patent Documents 1, 2, and 3, the electron beam energy is attenuated as the irradiation distance is increased, which is the same as the conventional electron beam irradiation apparatus shown in FIGS. In the case of a gaseous compound which is an odorous substance such as high concentration hydrogen sulfide, it cannot be decomposed with high efficiency.

  In view of such circumstances, the present invention is an electron beam that can be decomposed at a low cost and with high efficiency even when the substance contained in the gas is a gaseous compound that is an odorous substance such as high-concentration hydrogen sulfide. The object is to provide an irradiation apparatus.

  In the electron beam irradiation apparatus of the present invention, an irradiation window is provided on one surface in a direction substantially perpendicular to the gas flow direction of the gas processing chamber body, and the gas processing is performed by the electron beam irradiated through the irradiation window. An electron beam irradiation apparatus configured to decompose a gaseous compound such as an odor substance in a gas passing through a chamber body, wherein a baffle plate is provided in the gas processing chamber body, and a front end portion of the baffle plate is provided. A flow path through which gas flows is formed between the irradiation window and the irradiation window.

  In the electron beam irradiation apparatus of the present invention, two baffle plates are provided at predetermined intervals in the direction along the gas flow direction, and the baffle plates are centered in the direction along the gas flow direction of the irradiation window. As a reference, when the dimension from the surface away from the irradiation window side of the gas processing chamber main body to the surface of the gas processing chamber main body side of the irradiation window is defined as 100, it is an obstacle. When the projection amount toward the irradiation window side of the plate is set to a ratio of 65 to 75 and the length of the gas processing chamber main body in the direction along the gas flow direction is 100, the interval in the direction along the gas flow direction of the baffle plate is The irradiation window has a titanium foil, and the gas compound to be decomposed is hydrogen sulfide.

  In the present invention, a gaseous compound containing an odorous substance such as hydrogen sulfide is guided by a baffle plate and flows on the lower surface side of the irradiation window in the main body of the gas processing chamber. Therefore, the gaseous compound is irradiated with a high energy electron beam. The odorous substance in the gaseous compound is decomposed.

  According to the electron beam irradiation apparatus of the present invention, even when the substance contained in the gaseous compound is an odorous substance such as high-concentration hydrogen sulfide, it can be decomposed at low cost and with high efficiency. Can have an effect.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 to 4 show an example of an embodiment of the present invention. In the figure, the same reference numerals as those shown in FIGS. 8 to 10 denote the same components, and the basic configuration is shown in FIGS. This is substantially the same as the conventional one shown in FIG. In the following description, the horizontal portion of the line D shown in FIG. 1, which is the direction in which the gas 10, 10 ′ travels in the duct-like portions 9 a, 9 b of the gas processing chamber 9, is “the direction along the gas flow direction”. That's it.

  1 to 3, reference numerals 31 and 32 denote two baffle plates erected on the inner bottom surface 9 'of the gas processing chamber main body 9c so as to be positioned directly below the irradiation window 21. The baffle plates 31 and 32 are arranged at a predetermined interval in the direction along the gas flow direction, and the direction along the gas flow direction with reference to the center of the irradiation window 21 in the direction along the gas flow direction. The gas processing chamber body 9c extends to the full inner width.

  When the chamber height H1 from the bottom surface 9 ′ of the gas processing chamber main body 9c to the lower surface of the irradiation window 21 is 100, the baffle plate height H2 is set to a ratio of 65 to 75, and the gas processing chamber main body 9c moves in the gas flow direction. When the length (short side length) L1 in the direction along the direction is 100, the distance L2 between the baffle plates 31 and 32 is set to a ratio of 45 to 55.

  The baffle plates 31 and 32 are arranged in this way because the electron beam energy inside the gas processing chamber main body 9c decreases from the upper part of the gas processing chamber main body 9c (the lower surface of the titanium foil 21a of the irradiation window 21). A flow path 33 of the gas 10 in the gas processing chamber main body 9c is formed between the upper ends of the baffle plates 31 and 32 and the lower surface of the titanium foil 21a of the irradiation window 21, and is positioned on the lower surface side of the titanium foil 21a having high electron beam energy. This is because the gas comes into contact with the high-energy electron beam 22.

  In addition, the ratio of the baffle plate height H2 to the chamber height H1 is set to 65 to 75 in order to process high-concentration hydrogen sulfide with high decomposition processing efficiency, the average gas in the gas processing chamber main body 9c. When the flow rate is about 3.6 m / s to 4.0 m / s and the short side length L1 of the gas processing chamber body 9c is 0.143 m, the contact time between the gas 10 and the electrons is 0.143 / 4 to 0.33. This is because 143 / 3.6 seconds, that is, 0.035 seconds to 0.04 seconds.

  In addition, the inventors have shown that the contact time between the gas and the electron is about 0.035 seconds or less by experiments, so that the decomposition treatment efficiency is lowered because of the short contact time. Since the height of 32 is reduced, the knowledge that the gas 10 passing through the low energy part of the electron beam 22 is increased and the decomposition efficiency is lowered is obtained.

  Further, the ratio of the distance L2 between the baffles 31 and 32 to the short side length L1 = 100 of the gas processing chamber main body 9c is set to 45 to 55, so that the contact time is kept at about 0.035 seconds to 0.04 seconds or less. On the other hand, the titanium foil 21a (width 560 mm × length 180 mm in the direction along the gas flow direction) is set to an optimum interval for bringing the gas 10 into uniform contact with the entire lower surface.

  In addition, the inventors have conducted experiments that when the ratio of the distance L2 between the baffle plates 31 and 32 to the short side length L1 = 100 of the gas processing chamber main body 9c is 45 or less, the gas 10 flows into the lower surface of the titanium foil 21a. If the ratio of the interval L2 is 55 or more, the contact time is 0.035 seconds or less and the decomposition processing efficiency is reduced. We have knowledge.

Next, the operation of the above-described embodiment will be described.
In the electron beam irradiation apparatus of the illustrated example, the gas 10 to be processed is introduced into the gas processing chamber 9 and rectified by the rectifying plate 12, and the conventional gas processing chamber main body 9c as shown by the hatched lines C in FIG. Disperse in the flow path 33 which is a narrow area at a position higher than that of the apparatus.

  Thus, when a voltage of about 30 to 40 V is applied from the filament power supply 15a to the tungsten filament 18 through the high voltage introducing rod 14 and the high voltage conducting rods 16a and 16b, thermoelectrons are generated from the tungsten filament 18. The thermoelectrons generated in the tungsten filament 18 are accelerated by a high electric field generated between the acceleration electrode 19 and the titanium foil 21a by a high voltage of about 150 kV applied from the acceleration power supply 15b. As a result, the acceleration electrode 19 is accelerated. A high-speed electron beam 22 is irradiated toward the irradiation window 21, and the electron beam 22 transmitted through the irradiation window 21 contacts the gas 10 flowing through the gas processing chamber 9 in the gas processing chamber body 9c. For this reason, gaseous compounds such as odorous substances such as high-concentration hydrogen sulfide are decomposed, and the cleaned gas 10 'is discharged downstream.

  In the gas processing chamber 9, the gas 10 that has traveled straight through the duct-like portion 9 a bends on the upstream side of the baffle plate 31 and flows upward, and a flow path between the upper end of the baffle plate 31 and the lower surface of the irradiation window 21. It goes straight through 33, bends and flows downward, and goes straight in the duct-like portion 9b (see line D in FIG. 1).

  According to the illustrated example, since the gas 10 introduced from the duct-like portion 9a of the gas processing chamber 9 to the gas processing chamber main body 9c can come into contact with the high energy electron beam 22, odorous substances such as high-concentration hydrogen sulfide are not present. The gas 10 ′ is decomposed and cleaned with high processing efficiency, and is sent to the subsequent process from the duct-like portion 9b.

  FIG. 4 shows a processing facility using the electron beam irradiation apparatus shown in FIGS. In the figure, 34 is a mist separator for removing moisture from the gas 10 containing odorous substances such as high-concentration hydrogen sulfide supplied from the wastewater treatment plant 35, and 36 is a gas supplied from the mist separator 34. An electron beam irradiation apparatus 37 for processing is an adsorption / decomposition for decomposing and removing undecomposed odorous substances and ozone by-produced by the electron beam irradiation apparatus 36 from the gas 10 ′ supplied from the electron beam irradiation apparatus 36. The catalyst tower 38 is a fan for exhausting the gas 10 ′ cleaned by the adsorption / catalyst tower 37.

  As shown in FIG. 4, the gas 10 containing odorous substances such as hydrogen sulfide generated from the wastewater treatment plant 35 is removed through the mist separator 34 and guided to the electron beam irradiation device 36 to be odorous substances such as hydrogen sulfide. Is decomposed. Thereafter, other undecomposed odorous substances, by-product ozone and the like are decomposed and removed by the adsorption / catalyst tower 37 to become a purified gas 10 ′, which is exhausted by the fan 38.

  Subsequently, when the baffle plate is provided on the gas processing chamber main body as in the electron beam irradiation apparatus of the illustrated example of the present invention, and when the baffle plate is not provided on the gas processing chamber main body as in the prior art, sulfurization is performed. The experimental results of hydrogen decomposition efficiency will be described with reference to FIG. 5, [Table 1], [Table 2], and FIG.

  FIG. 5 shows the arrangement of the experimental apparatus. In the figure, 41 is a pretreatment unit such as a mist separator, 42 is an electron beam irradiation apparatus with or without a baffle plate, and 43 is a standard. Hydrogen sulfide gas injection means for injecting hydrogen sulfide gas, which is a gas, into the electron beam irradiation device 42, 44 is a gas measuring device for measuring the concentration of hydrogen sulfide in the gas sent from the electron beam irradiation device 42, 45 A blower 46 is a post-processing unit.

  Thus, in the experiment, the acceleration voltage and beam current of the electron beam irradiation device 42 are set to predetermined values, and the gas flow rate set to the line from the hydrogen sulfide gas injection means 43 of the experimental device shown in FIG. The raw odor hydrogen sulfide gas is injected so that the injected raw odor hydrogen sulfide gas is processed using the electron beam irradiation device 42 when there is a baffle plate and when there is no baffle plate, and hydrogen sulfide decomposition treatment is performed for each set condition. The subsequent hydrogen sulfide concentration was measured by the gas measuring device 44. In this experiment, the raw odor hydrogen sulfide concentration with the baffle plate is 45 ppm, and the raw odor hydrogen sulfide concentration without the baffle plate is 44 ppm.

  Also, based on the acceleration voltage, beam current, and gas flow rate that have been set, the absorbed dose, which is the energy absorbed per unit mass of hydrogen sulfide gas, is obtained using [Equation 1] and decomposed using [Equation 2]. Processing efficiency was determined. When the calculated decomposition treatment efficiency is shown in a table corresponding to the absorbed dose, it is as shown in [Table 1] and [Table 2], and when it is shown in a graph, it is a diagram shown in the graph shown in FIG. .

[Table 1] shows the case with a baffle, and [Table 2] shows the case without a baffle. In the graph of FIG. 6, a circle indicates a case with a baffle plate, and a black square indicates a case without a baffle plate. From these [Table 1], [Table 2] and the graph of FIG. 6, it can be seen that the presence of the baffle plate improves the decomposition efficiency (%) of hydrogen sulfide.
[Equation 1]
Absorbed dose = [1.6587 × acceleration voltage−126.8] × beam current ÷ gas flow rate (kGy = k J / kg)
[Equation 2]
Decomposition efficiency = {[(original hydrogen sulfide concentration) − (hydrogen sulfide concentration after hydrogen sulfide decomposition treatment)] / (original hydrogen sulfide concentration)} × 100

  In this illustrated example, a non-scanning electron beam irradiation apparatus that does not use a scan coil has a high degree of contribution to direct action in high-concentration hydrogen sulfide treatment compared to the discharge plasma method, low cost, and high decomposition efficiency. The scanning type using the scanning coil is not used for the following reason. That is, since this apparatus is a low energy apparatus with an acceleration voltage of 150 kV at the maximum, in the case of the scanning type shown in FIG. 11, the distance until the electron beam comes into contact with the gas to be processed becomes large at the end in the gas flow direction. As a result, the energy distribution becomes more non-uniform between the center and the end of the gas flow direction, and the non-scan type without a scan coil has a more uniform energy distribution. This is because there is no merit to add an element.

  In the electron beam irradiation apparatus of the illustrated example, even when the substance contained in the gas is a gaseous compound such as an odorous substance such as high-concentration hydrogen sulfide, it can be decomposed at low cost and with high efficiency.

  In the electron beam irradiation apparatus of the present invention, the case of irradiating the electron beam from the upper side to the lower side has been described. However, the electron beam irradiation device can be implemented by irradiating in the horizontal direction or from the lower side to the upper side. The description has been given of the case where two baffle plates are provided. However, it is needless to say that one can be implemented, and various modifications can be made without departing from the scope of the present invention.

It is a sectional side view which shows an example of embodiment of the electron beam irradiation apparatus of this invention. It is an II-II direction arrow line view of FIG. It is a III-III direction arrow line view of FIG. FIG. 5 is a layout diagram showing a processing flow of equipment using the electron beam irradiation apparatus shown in FIGS. 1 to 4. It is a layout diagram showing the processing flow of the experimental processing equipment. It is a graph which shows the decomposition processing efficiency of the hydrogen sulfide gas calculated | required based on the density | concentration of the hydrogen sulfide gas using the experimental processing equipment of FIG. It is a layout diagram showing a processing flow of a conventional biological deodorization apparatus. It is a sectional side view which shows an example of embodiment of the conventional electron beam irradiation apparatus. It is the IX-IX direction arrow directional view of FIG. It is a XX direction arrow line view of FIG. It is a sectional side view which shows the other example of the conventional electron beam irradiation apparatus. In the electron beam irradiation apparatus shown in FIG. 8, it is a schematic diagram of the gas processing chamber main body for demonstrating that the energy of an electron beam attenuate | damps as it leaves | separates from an irradiation window. It is a graph which shows the relationship between the electron beam energy and the mass stopping power of the electron beam in titanium. It is a graph which shows the relationship between the electron beam energy and the mass stopping power of the electron beam in the air.

Explanation of symbols

9 'bottom surface 9c gas processing chamber body 10 gas 10' gas 21 irradiation window 21a titanium foil 22 electron beam 31 baffle plate 32 baffle plate 33 flow path H1 chamber height (irradiation window from the surface away from the irradiation window side of the gas processing chamber body) The dimensions up to the surface of the gas processing chamber main body side)
H2 baffle plate height (projection amount of baffle plate toward irradiation window)
L1 short side length (length in the direction along the gas flow direction of the gas processing chamber body)
L2 interval (interval in the direction along the gas flow direction of the baffle plate)

Claims (7)

  An irradiation window is provided on one surface in a direction substantially perpendicular to the gas flow direction of the gas processing chamber main body, and an electron beam irradiated through the irradiation window causes the gas in the gas passing through the gas processing chamber main body to pass through the gas processing chamber main body. An electron beam irradiation apparatus configured to decompose a gaseous compound such as an odor substance, and a baffle plate is provided in the gas processing chamber main body so that gas flows between the front end portion of the baffle plate and the irradiation window. An electron beam irradiation apparatus characterized in that a flow path is formed.   The electron beam irradiation apparatus according to claim 1, wherein two baffle plates are provided at predetermined intervals in a direction along the gas flow direction.   The electron beam irradiation apparatus according to claim 2, wherein the baffle plates are symmetrically arranged in a direction along the gas flow direction with reference to a center of the irradiation window in the direction along the gas flow direction.   When the dimension from the surface separated from the irradiation window side of the gas processing chamber body to the surface of the irradiation window on the gas processing chamber body side is 100, the amount of protrusion of the baffle plate toward the irradiation window side is set to a ratio of 65 to 75. Item 4. The electron beam irradiation apparatus according to any one of Items 1 to 3.   The distance in the direction along the gas flow direction of the baffle plate is set to a ratio of 45 to 55 when the length in the direction along the gas flow direction of the gas processing chamber main body is set to 100. Electron beam irradiation device.   6. The electron beam irradiation apparatus according to claim 1, wherein the irradiation window includes a titanium foil.   The electron beam irradiation apparatus according to claim 1, wherein the gas compound to be decomposed is hydrogen sulfide.

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