TWI729448B - Device for removing harmful exhaust gas from plasma - Google Patents

Abstract

The present invention is to provide a device for removing harmful exhaust gas with plasma, so that the entire amount of exhaust gas thrown into a thermal decomposition tower must pass through a high-temperature region formed by a plasma jet to be surely decomposed.

The present invention is a method of concentrating a plurality of plasma jets (P) toward a point (Q), from a plurality of plasma jet torches (2a, 2b, (2c) installed toward the reaction space (D) of the exhaust gas (H) )), each plasma jet (P) is generated toward a certain point (Q) in the reaction space (D), and exhaust gas is exhausted from between the plurality of plasma jet torches (2a, 2b, (2c)) ( H) Supply toward the aforementioned point (Q).

Description

Device for removing harmful exhaust gas from plasma

The present invention relates to an improvement of a device for removing harmful exhaust gas by plasma in the thermal decomposition process of exhaust gas discharged from the semiconductor manufacturing process.

Various compound gases are used in the manufacturing process of electronic devices such as semiconductors or liquid crystals, for example, _{perfluorocarbons such as CF 4} and C ₂ F ₆ or carbon-free ones such as NF ₃ Perfluoro compounds such as fluorides (hereinafter referred to as "PFC") are used as cleaning gases for chemical vapor deposition chambers (CVD chambers). In addition, in this patent specification, exhaust gas containing perfluorinated compounds is referred to as perfluorinated compound exhaust gas or PFC exhaust gas.

Among them, since _{perfluorocarbons represented by CF 4} or C ₂ F ₆ are non-flammable and the compound itself is stable, if it is released into the atmosphere, it will stay unchanged for a long period of time. The lifespan to be consumed in the atmosphere is _{50,000 years for CF 4} and 10,000 years for C ₂ F _6. Furthermore, the global warming coefficient ( _{compared with CO 2} as 1) is _{4,400 for CF 4 and} 4,400 for C ₂ F ₆ 6,200 (after 20 years), the so-called greenhouse effect that cannot be allowed on the global environment has arisen, so it is expected that PFC containing perfluorocarbons represented _{by CF 4} or C ₂ F _{6 can be removed} means.

However, due to the stable CF binding of PFCs, especially perfluorocarbons (the binding energy is 130kcal/mol), it is not easy to decompose. It is extremely difficult to complete the PFC by general thermal decomposition methods such as combustion. Remove. For example, in the case of simple thermal decomposition, in _{the case of C 2} F ₆ , if the decomposition method is to cut off the CC bond, if the processing temperature is limited to 1,000 ℃, the processing air volume below 250 liters/min can remove the harmful For CF ₄ , it is necessary to cut off the CF with the largest binding energy. Even in the above-mentioned air volume, a high temperature of about 1,400~1,500°C is required.

As a technology for decomposing such a semiconductor exhaust gas containing PFC which is difficult to decompose, it is proposed that the PFC exhaust gas _{containing CF 4 can be thermally decomposed with a simple structure and a small amount of energy consumption.} Exhaust gas treatment system (Patent Document 1).

The exhaust gas treatment system is to arrange a plasma jet torch (torch) vertically downward on the top plate of the thermal decomposition tower, apply a discharge voltage between non-moving electrodes to generate an arc, and deliver working gas to the arc. The anode side vertically aligns the plasma jet with a high temperature of about 10,000°C on the central axis of the thermal decomposition tower and ejects the plasma jet. In addition, the PFC exhaust gas is supplied from the outside toward the vicinity of the upstream portion on the anode side of the generated plasma jet, and water-soluble components and dust are removed by washing with water, and water is added. The supplied PFC exhaust gas is helically rotated around the high-temperature plasma jet and discharged toward the outlet. During this period, it is thermally decomposed in the high-temperature environment surrounding the so-called high-temperature plasma jet at about 10,000°C. Discharged to the outlet scrubber (scrubber). _{With this, CF 4,} etc., which cannot be decomposed by conventional electric heaters, can be decomposed quickly and irreversibly.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2005-205330 A

However, in the exhaust gas treatment system described above, the thermal decomposition tower as a device for removing harmful exhaust gas with plasma has the following problems.

As described above, the PFC exhaust gas is supplied from the outside toward the vicinity of the upstream portion of the elongated and vertically extending plasma jet, and it is spirally rotated around it, and it is thermally decomposed in the process. However, due to the temperature of approximately 10,000°C The plasma jet has a slender shape, and the high temperature area around 1,400~1,500°C formed around it will inevitably become slender and long. In particular, in the vicinity of the inner surface of the thermal decomposition tower, a space that does not reach the temperature of the above-mentioned high-temperature region is also generated away from the plasma jet. Therefore, as long as all the exhaust gas is not thermally decomposed by passing through the high-temperature region formed around the plasma jet, a part of the exhaust gas may pass through the low-temperature region and be directly released without being decomposed.

The present invention is developed in view of such problems. The purpose of solving the problem is to provide a method and a device for removing harmful exhaust gas from plasma, which can be used to put into the thermal decomposition tower of the device for removing harmful exhaust gas from plasma. The entire exhaust gas must pass through the high temperature area formed by the plasma jet. It is definitely broken down.

The invention described in claim 1 (a method for removing harmful exhaust gas with plasma) is a method for concentrating a plurality of plasma jets P toward a point Q, and is characterized in that the plurality of plasma jets P are installed from the reaction space D toward the exhaust gas H The plasma jet torches 2a, 2b, (2c) are directed toward a certain point Q in the reaction space D to generate each plasma jet P, and then from the plurality of plasma jet torches 2a, 2b, (2c), The exhaust gas H is supplied toward the aforementioned point Q.

The invention described in claim 2 (a method of removing harmful exhaust gas with plasma) is a method of dispersing a plurality of plasma jets P at a plurality of points Q1, Q2, (Q3) around the point Q, and is characterized by: The plurality of plasma jet torches 2a, 2b, (2c) set toward the reaction space D of the exhaust gas H are directed toward the plurality of points Q1, Q2, (Q3) around a certain point Q in the reaction space D to maintain each other The way of twisting the positional relationship causes each plasma jet P to be generated, and then from the plurality of plasma jet torches 2a, 2b, (2c), the exhaust gas H is directed toward the points Q1, Q2, (Q3) formed in the above-mentioned plurality of plasma jet torches 2a, 2b, and (2c). ) Is supplied in the high temperature region T between.

The invention described in claim 3 is a device for realizing the method of claim 1 (thermal decomposition tower 1 for removing harmful exhaust gas from plasma), and is characterized by: A tower body 1a having a reaction space D of exhaust gas H inside, a plurality of plasma jet torches 2a, 2b, (2c), and a plurality of plasma jet torches arranged on the top plate portion 3 of the tower body 1a 2a, 2b, and (2c) are formed by an exhaust gas supply portion 29 provided on the top plate portion 3 of the tower body 1a; the plurality of plasma jet torches 2a, 2b, (2c) are arranged separately The plasma jets P respectively generated from the plasma jet torches 2a, 2b, (2c) are directed toward the point Q in the reaction space D; the jet port 29a of the exhaust gas supply part 29 is used to discharge the exhaust gas H It is arranged in such a way as to supply to the above-mentioned point Q.

The invention described in claim 4 is a device for realizing the method of claim 2 (pyrolysis tower 1 for removing harmful exhaust gas from plasma), and is characterized by: having a reaction space D of exhaust gas H inside The tower body 1a, and the plurality of plasma jet torches 2a, 2b, (2c), and the plurality of plasma jet torches 2a, 2b, (2c) are arranged between the above-mentioned plurality of plasma jet torches 2a, 2b, and (2c) provided on the top plate portion 3 of the above-mentioned tower body 1a The exhaust gas supply part 29 of the top plate part 3 of the tower body 1a is constituted; the plurality of plasma jet torches 2a, 2b, (2c) are separately arranged so that the plasma jet torches 2a, 2b, (2c) The plasma jets P respectively generated are directed to a plurality of points Q1, Q2, (Q3) set around a certain point Q in the reaction space D, maintaining a mutually twisted positional relationship; the exhaust gas supply part 29 The ejection port 29a is performed by directing the exhaust gas H toward the high temperature region T formed between the above-mentioned plural points Q1, Q2, and (Q3). Configured by the way of supply.

Claim 5 is that in Claim 4, the high temperature region T of the plasma jet P generated from the plurality of plasma jet torches 2a, 2b, (2c) is the points Q1, Q2, (Q3) that share the above-mentioned plural numbers. Within the above point Q.

The present invention starts from the supply relationship of the exhaust gas H with respect to the plurality of plasma jets P, so that the entire amount of the exhaust gas H is passed through the high temperature region T formed by the plurality of plasma jets P, so that harmful effects can be removed. The efficiency of exhaust gas H is dramatically improved. Moreover, compared to the case where the positional relationship of the plurality of plasma jets P is concentrated on the point Q, the positional relationship of the plurality of plasma jets P is dispersed at the plurality of points Q1, Q2, (Q3) around it, and the The high temperature area T located in the reaction space D of the exhaust gas H is further expanded. Furthermore, in this case, it is extremely important that the high temperature region T formed by the plurality of plasma jets P includes the point Q, and a part of which overlaps each other.

A: Water treatment device

B: Thermal decomposition device

D: reaction space

E: circle

H: Exhaust

L: central axis

M: Water, etc. (fog, heating steam, water for circulation)

P: Plasma jet

Q: 1 point

Q1~Q3: surrounding points

S: Semiconductor manufacturing equipment (semiconductor film forming equipment)

T: High temperature area

U: Vortex

V: Vacuum pump

X: (invention) exhaust gas treatment device

1: Thermal decomposition tower

1a: Tower body

1b: carcass

1c: feet

2(2a~2c): plasma jet torch

3: Top plate

4: puddle

5: Water Wall

18: Exhaust gas introduction piping

19: Exhaust gas inlet nozzle

20: Water treatment tank

21: Steam piping

21a: nozzle opening facing upward

22: Exhaust introduction part

23: Spray piping on the inlet side

23b: Nozzle orifice facing downward

25: Filling layer on the inlet side

26: Exhaust pipe

29: Exhaust supply section

29a: Ejector

30: Water Supply Department

31: Pumping piping on the inlet side

34: Pump on the inlet side

37: Overflow piping

40: sink

41: Top plate

42: Overflow piping

45: water supply pipe

60: Outlet scrubber

60a: Scrubber body

61: Pumping piping on the outlet side

63: Spray piping on the outlet side

63a: nozzle port

64: Pump on the outlet side

65: Filling layer on the outlet side

67: Exhaust blower

68: Exhaust pipe for release to atmosphere

[Figure 1] is a flow diagram of the entire device of the present invention.

[Figure 2] is a plan view of a transverse section including a point Q when there are two plural plasma jets of the present invention.

[Fig. 3] is a plan view of a transverse section including point Q in another example of Fig. 2. [Fig.

[Figure 4] is the inclusion of a plurality of plasma jets of the present invention when there are 3 Plan view of the transverse section of point Q.

[Fig. 5] is a plan view of a transverse section including point Q in another example of Fig. 4. [Fig.

Hereinafter, the present invention will be explained based on the illustrated embodiments. Figure 1 is an exhaust gas treatment device X of the present invention. These devices are used in the semiconductor manufacturing process. For example, the vacuum pump V sucks the exhaust gas (exhaust gas) H discharged from the CVD film forming device S and sends it to the exhaust gas treatment device X for heating. A device that decomposes and makes it harmless before releasing it into the atmosphere.

In addition, in the description of the prior art, although the removal of harmful substances in the PFC exhaust gas is used as a representative example, the exhaust gas that is difficult to decompose is not limited to the PFC exhaust gas. Therefore, the processing target gas of the present invention Just call it exhaust H.

The exhaust gas treatment device X in FIG. 1 is just one example, and is composed of an independent water treatment device A and a thermal decomposition device B with a scrubber 60 at the outlet. Although not shown here, the water treatment device A may be provided integrally with the water tank 40 of the thermal decomposition device B.

The outline of the flow path of the exhaust treatment device X in Fig. 1 is as follows. The exhaust gas H discharged from the CVD film forming apparatus S is sucked by the vacuum pump V, and the exhaust gas H is sent to the water treatment apparatus A through the exhaust gas introduction pipe 18 connecting the vacuum pump V and the water treatment apparatus A. In the water treatment device A, the water-decomposable component gas contained in the exhaust gas H is hydrolyzed to form a solid hydrolysis product, which is combined with the supplied water (spray water for hydrolysis or the addition of water). Hot water vapor) M is removed together. At the same time, the dust sent in with the exhaust gas H is also washed and removed by water in the same way. In addition, if it contains water-soluble gas such as chlorine, it is also removed by M such as water at the same time.

The exhaust gas H from which the hydrolyzable component gas and dust have been removed is sent to the thermal decomposition tower 1 through the exhaust pipe 26, where it is thermally decomposed, and then sent to the scrubber 60 on the adjacent outlet side. After the thermally decomposed exhaust gas H after thermal decomposition is cleaned, the exhaust gas H is released into a harmless atmosphere and released into the atmosphere.

The water treatment device A of the exhaust treatment device X is composed of: a water treatment tank 20 with an exhaust gas introduction nozzle 19 and a filling layer 25 on the inlet side, a water supply unit 30, a steam pipe 21, and an exhaust pipe. It is roughly constituted by 26.

The water treatment tank 20 is a hollow container. The exhaust gas introduction part 22 at the top is provided with an exhaust gas introduction nozzle 19, and the water M for circulation is stored at the bottom.

Below the exhaust gas introduction nozzle 19, a steam pipe 21 connected to a steam supply pipe (not shown in the figure) of a factory is provided. In the steam pipe 21, the upward nozzle opening 21a is arranged on both sides of the exhaust gas introduction nozzle 19 with the exhaust gas introduction nozzle 19 interposed therebetween. Therefore, on both sides of the exhaust gas introduction nozzle 19, it is possible to heat the steam from upward. The nozzle opening 21a ejects upward.

Below or on the side of the steam pipe 21, spray pipes 23 on the inlet side are arranged side by side. The spray pipe 23 on the inlet side is provided with a nozzle opening 23b facing downward. The downward nozzle opening 23b is arranged directly below the exhaust gas introduction nozzle 19, and fine spray water droplets M are sprayed radially downward from the downward nozzle opening 23b.

Below the spray pipe 23 on the inlet side, a plastic, ceramic, or glass filler (for example, Tellerette (registered trademark)) or Raschig ring is installed. )的filling layer 25.

In the space below the filling layer 25, an exhaust pipe 26 drawn from the space is provided, and the exhaust pipe 26 is an exhaust gas supply part 29 that reaches the thermal decomposition tower 50 described later.

The spray pipe 23 on the inlet side is connected to a water pumping pipe 31 that stands up from the bottom of the water treatment tank 20 and constitutes the inlet side of the water supply unit 30. The water pumping pipe 31 on the inlet side is provided with a water pumping pump 34 on the inlet side for supplying the circulating water M stored in the bottom of the water treatment tank 20 to the spray pipe 23 on the inlet side. Furthermore, at the bottom of the water treatment tank 20, an overflow pipe 37 for maintaining the water level of the circulating water M is provided, and the overflow amount of water is supplied from the outside.

The thermal decomposition device B is composed of a water tank 40, a thermal decomposition tower 1 as a plasma removing harmful exhaust device, and a scrubber 60 on the outlet side. The pyrolysis tower 1 and the scrubber 60 on the outlet side are arranged on the water tank 40 in an upright manner.

The thermal decomposition tower 1 is composed of a tower body 1a and a plurality of non-moving plasma jet torches 2. The plasma jet torch uses a plural number of tools, which is represented by the symbol 2 when used in the upper concept, and the English letter is used as the branch number when it is used individually.

The tower body 1a is a cylindrical member, the upper end of which is formed in an upward conical shape and is sealed with a top plate part 3, and the central top is connected to the exhaust pipe 26 of the exhaust gas supply part 29. The lower end of the tower body 1a is open toward the water tank 40. When there are two plasma jet torches 2 installed on the top plate part 3, they are symmetrically arranged on both sides of the exhaust gas supply part 29; when there are three or more, they are installed at equal angles. The exhaust gas supply part 29 is on the circle at the center. That is, in the case of 3 cases, the interval is 120°.

Since the top plate portion 3 of the tower body 1a is formed in an upward conical shape, the plasma jet P generated from each plasma jet torch 2 becomes inclined with respect to the central axis L of the tower body 1a. Therefore, the inner surface of the trunk portion 1b of the tower body 1a must be set at a distance far enough away from the front end of the plasma jet P without being affected by heat, and thus is formed thickly. In addition, the lower end of the body portion 1b is reduced to a funnel shape, and is connected to the leg portion 1c erected on the top plate portion 41 of the water tank 40 to be integrated.

The outer surface of the body part 1b is covered with a heat insulating material (not shown). A water depression 4 is provided on the outer peripheral portion of the upper end of the tower main body 1a, and water overflows from the upper end of the tower main body 1a to form a water wall 5 on the entire inner peripheral surface of the tower main body 1a. The overflowing water in the puddle 4 is supplied from the outside.

The plasma jet torch 2 uses a plurality of tools. In the case of individual representation, the symbols are marked with English letters as branch symbols in the form of 2a, 2b, and 2c. The plasma jet torch 2 has a plasma generation chamber (not shown in the figure) inside. The plasma jet torch 2 is provided at the center of the lower surface of the plasma jet torch 2 to eject the plasma jet P generated in the plasma generation chamber Plasma jet ejection holes (not shown in the figure). On the upper side of the plasma jet torch 2, a working gas delivery pipe such as nitrogen (not shown in the figure) can be installed as required.

The bottom of the thermal decomposition tower 1 and the scrubber 60 on the outlet side are facing The water tank 40 is open; the bottom of the thermal decomposition tower 1 and the bottom of the scrubber 60 on the outlet side are connected by the space between the top plate 41 of the water tank 40 and the circulating water M.

The minimum number of plasma jet torches 2 is 2, and it is 3 in Figures 4 and 5. Of course, 3 or more can be installed. First, a description will be given of a case where two devices are installed (Figures 2 and 3).

In the case of two plasma jet torches 2a and 2b, as described above, the exhaust gas supply part 29 is set in a bilateral symmetry.

The spray angle of the plasma jet P from the left and right plasma jet torches 2a, 2b, in the case of Figure 2, is relative to the center of the tower body 1a that passes through the exhaust gas supply part 29 provided at the top of the tower body 1a The axis L is inclined and is provided on the central axis L so as to face a certain point Q directly below the exhaust gas supply part 29. And the two plasma jets P from the left and right plasma jet torches 2a, 2b cross at a point Q. The front ends of the two plasma jets P are set so as not to affect the inner surface of the trunk 1b of the tower body 1a.

The central part of the plasma jet P is about 10,000°C, and the temperature drops as it moves away from the central part. The decomposable temperature region (a region above 1,400°C) of the target exhaust H formed in the entire periphery of the plasma jet P including the above-mentioned center portion is referred to as the high temperature region T, which is indicated by a dashed line and a partially hatched line. The high temperature region T is wider than the visible range of the plasma jet P. This point is the same in the case described later.

The situation in Figure 3 is that the two plasma jets P do not cross at the above point Q, but are set in such a way that the direction is set at two points Q1 and Q2 on the circle E on the horizontal plane containing the point Q with the point Q as the center. . In this case, if 2 points When Q1 and Q2 are too separated, the temperature of point Q as the center point may not reach the thermal decomposition temperature. To avoid this situation, pass through points Q1 and Q2 respectively, or face the two plasmas generated by these points. The high temperature region T of the jet P may include the range of the point Q. In other words, the high temperature region T of the two plasma jets P becomes the common point Q. This point will also be explained in Fig. 5 described later.

Thereby, the high-temperature region T of the two plasma jets P is centered on the point Q and spreads around it in a larger surface shape than in the case of FIG. 2.

In the case of Figure 4, there are three plasma jets P, and the plasma jet torches 2a, 2b, and 2c are installed at equal intervals of 120° with the exhaust gas supply part 29 as the center, and the plasma jets P are directed Point Q is set by the way of spraying. The three plasma jets P intersect at point Q from three directions, and a high temperature area T is formed around the plasma jet P. In this case, the upper surface of the high temperature region T is recessed toward the point Q in a funnel shape, and assumes a state surrounding the exhaust gas H, which will be described later.

In the case of Fig. 5, the three plasma jets P do not intersect at the aforementioned point Q, but are set to face three points Q1, Q2, and Q3 on the circle E on the horizontal plane centered on the point Q. In this case, as in Figure 3, if the above three points Q1, Q2, and Q3 are too separated, the temperature of the central point Q may not reach the thermal decomposition temperature. In order to avoid this situation, use The high temperature region T of the plasma jet P passing through the points Q1, Q2, and Q3, or the plasma jet P generated toward them, becomes a range that can include the point Q.

Thereby, the high-temperature region T of the plasma jet P is centered on the point Q and expands around the point Q into a larger surface than that in the case of FIG. 4. In this case, the high temperature The upper surface of the area T will also be dented in a funnel shape towards the point Q.

In addition, the position of the point Q from the exhaust gas supply part 29 is within the reach of the plasma jet P or the high temperature region T formed around it, and is selected so that the plasma jet P does not interfere with the tower The position within the scope of the damage caused by the main body 1a.

The exhaust gas supply part 29 is arranged on the top of the top plate part 3 of the tower body 1a as described above, and the distance to any plasma jet torch 2 is equal. In addition, the discharge port 29a of the exhaust gas supply unit 29 is arranged to supply harmful exhaust gas H toward the above-mentioned point Q or toward the high-temperature region T between the above-mentioned plural points Q1, Q2, and (Q3).

The water tank 40 is a hollow rectangular parallelepiped member, and the above-mentioned thermal decomposition tower 1 and the outlet scrubber 60 described later are standingly arranged on the top plate portion 41 of the water tank 40. The water tank 40 is filled with circulating water M at the bottom, and a flow path of the thermal decomposition exhaust gas H is formed between the water M and the top plate portion 41. In addition, the water tank 40 is provided with an overflow pipe 42 for keeping the internal water level constant, and a water supply pipe 45 for supplying the same amount of water as the overflowing water M to the water tank 40.

The scrubber 60 on the outlet side is a so-called wet scrubber. The schematic structure of the scrubber 60 is described below. It consists of a straight-tube scrubber body 60a erected on the top plate portion 41 of the water tank 40, and a pumping pipe 61 on the outlet side. , And a water pump 64 installed on the outlet side in the middle, and a spray pipe 63 on the outlet side connected to the water pumping pipe 61 and installed near the top of the inside of the scrubber body 60a, and the spray pipe 63 installed in the direction of The nozzle port 63a on the outlet side of spraying alkaline liquid, acidic liquid, etc., or steam or water M, and the nozzle port 63a provided on the outlet side is used to make The filling layer 65 on the outlet side in contact with the gas and liquid phases, an exhaust blower 67 provided on the top of the scrubber body 60a, and an exhaust pipe 68 for releasing to the atmosphere provided on the exhaust blower 67 are formed. The sprayed liquid medicine or water M is contained in the water tank 40.

Next, the function of the exhaust treatment device X in Fig. 1 will be described. The flow path from the water treatment device A of the exhaust gas treatment device X to the exhaust gas H of the outlet scrubber 60 is maintained by operating the exhaust gas blower 67 to maintain a negative pressure. In addition, the exhaust gas H from the semiconductor manufacturing apparatus S is sucked by the vacuum pump V as described above, and is sent to the water treatment apparatus A whose internal pressure is maintained through the exhaust gas introduction nozzle 19.

In the water treatment device A, the heated steam M is sprayed on both sides of the exhaust introduction nozzle 19 from the nozzle opening 21a facing upward of the steam pipe 21, and the pump 34 of the pumping pipe 31 on the inlet side is activated. The circulating water M is pumped up and supplied to the spray pipe 23 on the inlet side, and the water is also sprayed downward in an umbrella shape as fine water droplets M from the nozzle opening 23b facing downward.

The exhaust gas H sent into the water treatment device A is sent to the thermal decomposition tower 1 as the water-washed exhaust gas H by removing the water-decomposable component gas and dust by the above-mentioned heated steam M and the fine water droplets M.

Prior to the supply of the above-mentioned washing exhaust gas H, when the power of the control unit (not shown) of the plasma jet torch 2 is turned on (on), an ultra-high temperature (about 10,000°C) airflow will be generated under atmospheric pressure. That is, a non-moving plasma jet P is generated, and each plasma jet P is sprayed out of the tower body in the above-mentioned positional relationship from the plasma jet ejection holes of the plurality of plasma jet torches 2 Within 1a.

Since the exhaust gas H is directed: the intersection of the plasma jets P as the high temperature region T (Figures 2 and 4), in other words from the point Q or the plasma jet P (in other words, the point Q1, point Q2, (point Q3)) or the enclosed part (Figure 3, Figure 5) is blown in, so the entire amount of exhaust H blown in is passed through without leakage. The high temperature region T formed by the plasma jet P causes the entire amount to be decomposed.

Here, when the plasma jet P is in a twisted positional relationship as shown in (Figures 3 and 5), the plasma jet P flows between or surrounded by the plasma jet P A vortex U is generated in the atmosphere within the range of, and the exhaust gas H blown into the reaction space D from the discharge port 29a of the exhaust gas supply part 29 is drawn into the vortex U and directed toward the point Q as the center point.

In particular, when three plasma jet torches 2 are used, this tendency is more intense, and since the upper surface of the high-temperature area T is a funnel-shaped depression, the exhaust gas H has no place to escape, so it appears to be better than the two cases. High decomposition efficiency.

Then, the thermally decomposed exhaust gas H that has been thermally decomposed here is sent to the outlet scrubber 60, is sufficiently cleaned and lowered to a temperature that can be released to the atmosphere, and is released to the atmosphere by the exhaust blower 67.

Above, the best example of the present invention is shown as a representative example, and the present invention is not limited by these examples.

1: Thermal decomposition tower

1a: Tower body

1b: carcass

1c: feet

2a, 2b: plasma jet torch

3: Top plate

4: puddle

5: Water Wall

18: Exhaust gas introduction piping

19: Exhaust gas inlet nozzle

20: Water treatment tank

21: Steam piping

21a: nozzle opening facing upward

22: Exhaust introduction part

23: Spray piping on the inlet side

23b: Nozzle orifice facing downward

25: Filling layer on the inlet side

26: Exhaust pipe

29: Exhaust supply section

30: Water Supply Department

31: Pumping piping on the inlet side

34: Pump on the inlet side

37: Overflow piping

40: sink

41: Top plate

42: Overflow piping

45: water supply pipe

60: Outlet scrubber

60a: Scrubber body

61: Pumping piping on the outlet side

63: Spray piping on the outlet side

63a: nozzle port

64: Pump on the outlet side

65: Filling layer on the outlet side

67: Exhaust blower

68: Exhaust pipe for release to atmosphere

A: Water treatment device

B: Thermal decomposition device

D: reaction space

H: Exhaust

L: central axis

M: Water, etc. (fog, heating steam, water for circulation)

Q: 1 point

S: Semiconductor manufacturing equipment (semiconductor film forming equipment)

U: Vortex

V: Vacuum pump

X: Exhaust treatment device

Claims (3)

A device for removing harmful exhaust gas with plasma, which is characterized by: a tower body with a reaction space for exhaust gas inside, a plurality of plasma jet torches arranged on the top plate of the tower body, and the plurality of electric Between the plasma jet torches and set on the top plate of the tower body, the exhaust gas supply part is constituted; the plurality of plasma jet torches are separately arranged to make the plasma generated from the plasma jet torch separately The jet flow is directed to a point in the reaction space; and the ejection port of the exhaust gas supply unit is arranged to supply exhaust gas to the point. A device for removing harmful exhaust gas with plasma, which is characterized by comprising: a tower body having a reaction space for exhaust gas inside, a plurality of plasma jet torches arranged on the top plate of the tower body, and the plurality of Between the plasma jet torches and the exhaust gas supply part provided on the top plate of the tower body; the above plural plasma jet torches are separately arranged to make the plasma jet torches generated from the above plasma jet torches. The plasma jet is directed to a plurality of points set around a certain point in the reaction space to maintain a mutually twisted positional relationship; the discharge port of the exhaust gas supply part is to direct the exhaust gas in the above-mentioned complex It is arranged to supply the high temperature area formed between several points. The apparatus for removing harmful exhaust gas from plasma according to claim 2, wherein the high temperature region of the plasma jets generated from the plurality of plasma jet torches is the above-mentioned point among the above-mentioned plural points in common.

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