Waste gas treatment device using superheated steam

Abstract

This waste gas treatment device is provided with: a superheated steam generating unit 1, 1'; and a thermal decomposition chamber 3 provided below the superheated steam generating unit 1, 1' to thermally decompose waste gas T using superheated steam Q from the superheated steam generating unit.

Description

Waste gas treatment equipment using superheated steam

[0001] The present invention relates to a waste gas treatment device using superheated steam.

[0002] Large waste treatment plants, incinerators, and manufacturing plants use large amounts of fossil fuels to generate heat and burn carbon, organic compounds, etc., which produces carbon dioxide (CO ２ ), carbon monoxide (CO), water vapor (H ２ O), nitrogen (N ２ ), oxygen (O ２ ), soot, hydrogen chloride (HCl), sulfur oxides (SO ｘ ), nitrogen oxides (NO ｘ Incomplete combustion generates waste gases such as carbon monoxide (CO) gas and nitrogen oxides (NO), which are the most harmful to humans. ｘ ) gas, sulfur oxide (SO ｘ ) gases, dioxins, etc. are produced, and even complete combustion produces trace amounts of harmful gases.

[0003] In order to treat the above-mentioned waste gases, conventional waste treatment plants and incinerators have installed acid gas removal devices, NOx removal devices, etc. ｘ In addition, production plants are equipped with waste gas treatment equipment such as concentration treatment equipment, solvent recovery equipment, activated carbon adsorption equipment, scrubber equipment, volatile organic compound (VOC) treatment equipment, and equipment that releases gas into the atmosphere after high-temperature combustion using an afterburner.

[0004] However, the above-mentioned conventional waste gas treatment devices use fossil fuels and have low thermal efficiency, and therefore generate untreated waste gas, resulting in a problem of high environmental load.

[0005] In order to solve the above-mentioned problems, the waste gas treatment device of the present invention comprises a superheated steam generating unit and a pyrolysis chamber provided below the superheated steam generating unit for pyrolyzing waste gas using the superheated steam from the superheated steam generating unit.

[0006] According to the present invention, no fossil fuels are used, and superheated steam having unparalleled thermal energy is used, which is obtained by further heating saturated steam at approximately 100°C. This results in high thermal efficiency, and therefore, the amount of untreated waste gas is greatly reduced, resulting in a low environmental impact.

[0007] 1 is a front view showing a first embodiment of a waste gas treatment device according to the present invention. It is a top view of the condensation liquefaction unit of FIG. 1. It is a flowchart for explaining the operation of the waste gas treatment device of FIG. 1. It shows a first example of the superheated steam generation unit of FIG. 1, where (A) is a top view, (B) is a cross-sectional view along line B-B of (A), and (C) is a cross-sectional view along line C-C of (A). It shows details of the insulator structure of FIG. 4, where (A) is a bottom view and (B) is a cross-sectional view. It shows a second example of the superheated steam generation unit of FIG. 1, where (A) is a cross-sectional view and (B) is a view as seen from line B-B of (A). It is a front view showing a second embodiment of a waste gas treatment device according to the present invention. It is a view showing a modified example of the pyrolysis chamber of FIG. 1 and FIG. 7, where (A) is a cross-sectional view and (B) is a top view of the high-temperature heater of (A).

[0008] FIG. 1 is a front view showing a first embodiment of a waste gas treatment apparatus according to the present invention, and FIG. 2 is a top view of the condensation and liquefaction unit of FIG.

[0009] In Figure 1, a saturated steam generating unit 2 is connected to a superheated steam generating unit 1 for supplying saturated steam P. The saturated steam generating unit 2 heats hot water W, for example, at about 80°C, to generate saturated steam P at about 100°C to 120°C for the superheated steam generating unit 1, and is relatively small and electrically driven. An example of the saturated steam generating unit 2 is a light boiler manufactured by Nakamoto Corporation, model number trademark NBC2101R. The saturated steam P from the saturated steam generating unit 2 is supplied to a saturated steam inlet 11a of the superheated steam generating unit 1 via a solenoid valve 2a. The closed end 11b is shown in Figure 4(B) described below.

[0010] The superheated steam generating unit 1 supplies superheated steam Q having a temperature of 700° C. to 800° C. or 1000° C. to 1600° C., which is higher than the temperature of the saturated steam P, to the pyrolysis chamber 3. The structure of the superheated steam generating unit 1 will be described later.

[0011] A waste gas inlet 3a for introducing waste gas G1 is provided on the upstream side of the pyrolysis chamber 3, while a pyrolysis gas outlet 3b for extracting pyrolysis gas G2 is provided on the downstream side of the pyrolysis chamber 3. The bottom and sides of the pyrolysis chamber 3 are made of heat insulating material 31, so that the pyrolysis chamber 3 forms an airtight rectangular parallelepiped heat insulating structure. The pyrolysis gas outlet 3b is connected to a condensation and liquefaction unit 4 for condensing and liquefying the pyrolysis gas G2 and recovering it.

[0012] Now, let's explain thermal decomposition. The oxygen concentration dissolved in normal water at room temperature is about 0.6%. When water is converted into saturated steam P, its volume increases by 1600 times. Therefore, the oxygen concentration in the superheated steam Q in the thermal decomposition chamber 3 is 0.1 to 0.2%, and as a result, the thermal decomposition chamber 3 becomes almost oxygen-free. Therefore, even if the waste gas G1 is heated by the superheated steam Q at 700°C to 800°C or 1000°C to 1600°C, it is not oxidized or burned, but is instantly decomposed and rendered harmless. This decomposition is called thermal decomposition. In this case, the heat transfer from the superheated steam Q to the waste gas G1 is achieved by convection heat transfer as well as the most distinctive condensation heat transfer effect, so that the superheated steam Q acts as thermal energy with high thermal efficiency. The condensation heat transfer effect is such that when the temperature of the waste gas G1 to be heat treated is lower than 100°C, the superheated steam Q condenses into the waste gas G1, and since the condensation temperature is 100°C due to the large amount of condensation heat imparted at that time, the waste gas G1 shows a temperature rise similar to that of being heated in boiling water. The amount of condensation increases as the temperature of the waste gas G1 decreases, and condensation continues until the waste gas G1 reaches 100°C. In this superheated steam treatment, the waste gas G1 reaches 700°C in a short time, and when the falling rate drying rate period begins, the temperature of the waste gas G1 begins to rise above 100°C.

[0013] 2, the condensation and liquefaction unit 4 has an S-shaped heat exchanger 41 having a pyrolysis gas inlet 4a connected to the pyrolysis gas outlet 3b of the pyrolysis chamber 3 and a condensed liquid outlet 41b. The heat exchanger 41 is cooled by water in a water tank 42 having a water inlet 42a and a drain 42b. The water in the water tank 42 is connected to a water temperature conditioning unit (cold heat source, compressor) 43 and is cooled by a refrigerant in a refrigerant pipe 43a. In this case, the refrigerant in the refrigerant pipe 43a is, for example, CO ２The water temperature conditioning unit 43 sends compressed refrigerant liquid to the water tank 42 via a refrigerant pipe 43a, and recovers high-pressure refrigerant vapor heated by the water in the water tank 42 via the refrigerant pipe 43a. In other words, the water in the water tank 42 is cooled by the refrigerant in the refrigerant pipe 43a. At this time, the heat of the refrigerant in the refrigerant pipe 43a is efficiently transferred to the water in the water tank 42 by a fan 44 driven by a motor 44a.

[0014] When the dry distillation gas G2 is condensed and liquefied by the condensation liquefaction unit 4, the condensed liquid is recovered from the condensed liquid outlet 41b and discharged as a discharge or via a wastewater treatment device (not shown). In this case, trace amounts of residual hydrocarbon gases such as light gases, for example, methane gas, ethane gas, propane gas, and butane gas, are also discharged as a discharge or via a wastewater treatment device.

[0015] The control unit 5, which includes a power supply, controls the entire exhaust gas treatment device. That is, the control unit 5 is a computer comprising a central processing unit (CPU), read-only memory (ROM), flash memory, random access memory, input / output interface, analog-to-digital (A / D) converter, D / A converter, etc., and receives the temperature T1 of the superheated steam generation unit 1, the temperature T2 of the saturated steam generation unit 2, and the temperature T3 of the condensation and liquefaction unit 4 to control the superheated steam generation unit 1, the saturated steam generation unit 2, and the condensation and liquefaction unit 4.

[0016] Next, the treatment method of the waste gas treatment device of Figures 1 and 2 will be described with reference to the flowchart of Figure 3. The flowchart of Figure 3 is stored as a program in the ROM or flash memory of the control unit 5 and is executed by the control unit 5.

[0017] First, in step 301, an initial setting is performed. For example, the predetermined temperature T1 of the superheated steam generating unit 1 is set. ０ , the predetermined temperature T2 of the saturated steam generating unit 2 ０ , the predetermined temperature T4 of the condensation and liquefaction unit 4 ０ and set the processing time.

[0018] Next, in step 302, the saturated steam generating unit 2 is started up by the control signal C2.

[0019] Next, in step 303, the temperature T2 of the temperature sensor of the saturated steam generating unit 2 is A / D converted and taken in, and T2≧T2 ０ For example, it is determined whether the temperature is several hundred degrees Celsius. ０ Only if this is the case, proceed to step 304.

[0020] Next, in step 304, the solenoid valve 2a between the saturated steam generating unit 2 and the superheated steam generating unit 1 is turned on by the control signal C2', and the saturated steam P is supplied from the saturated steam generating unit 2 to the saturated steam inlet 11a of the superheated steam generating unit 1. As a result, after about 3 to 5 minutes, the superheated steam Q of the superheated steam generating unit 1 reaches an appropriate temperature, for example, T ０ The temperature becomes several hundred degrees Celsius, which is larger than the above. After measuring this time for about 3 to 5 minutes in step 305, the process proceeds to step 306.

[0021] Next, in step 306, the superheated steam generating unit 1 and the condensation and liquefaction unit 4 are started. Specifically, in the superheated steam generating unit 1, the control unit 5 controls the DC or AC voltage V applied between the electrodes 13a and 13b (described later) until the temperature T1 of the superheated steam generating unit 1 reaches a predetermined temperature T1 ０ For example, feedback control is performed so that the temperature is between 700°C and 800°C. In the condensation liquefaction unit 4, the control unit 5 controls the water temperature conditioning unit 43 of the condensation liquefaction unit 4 using the control signal C4, and drives the fan 44 by turning on the motor 44a using the control signal C4'. As a result, the control unit 5 controls the water temperature T4 of the water tank 42 of the condensation liquefaction unit 4 to be at a predetermined temperature T4 ０ For example, feedback control is performed so that the temperature is between 50°C and 60°C.

[0022] Next, in step 307, it is determined whether the processing time of the processing timer has elapsed, and after the processing time has elapsed, the process ends in step 308. That is, the saturated steam generating unit 2, the superheated steam generating unit 1, the water temperature conditioning unit 43 and the fan 44 of the condensation and liquefaction unit 4 are stopped by the control signals C1, C2, C4, and C4'.

[0023] During the treatment time, the waste gas G1 is thermally decomposed and the pyrolysis gas G2 is condensed and liquefied.

[0024] Figure 4 shows a first example of the superheated steam generating unit of Figure 1, where (A) is a top view, (B) is a cross-sectional view taken along line B-B of (A), and (C) is a cross-sectional view taken along line CC of (A). The superheated steam generating unit 1 of Figure 4 is a single-stage unit for generating high-temperature superheated steam of, for example, 700 to 800°C.

[0025] In Figure 4, the single-stage superheated steam generation unit 1 has an airtight rectangular parallelepiped insulation structure 11 consisting of an upper and surrounding area made of insulation material 111, a portion of the periphery made of joint material (which also serves as insulation) 112, a stainless steel frame 113 covering the insulation material 111 and the joint material 112, a handle 114 at the top of the stainless steel frame 113, and a mounting plate 115 at the bottom of the stainless steel frame 113. The insulation material 111 is, for example, felt or a plate-shaped molding material made of bulk fiber with inorganic and organic binders added. The joint material 112 is a hard insulation material, for example, concrete. The lower part of the rectangular parallelepiped insulation structure 11 is open at an open end OP1, into which a heating plate 14 (described below) is fitted. A saturated steam (or water) inlet 11a and a closed end 11b are inserted and fixed into the joint material 112.

[0026] In the superheated steam generating unit 1, a hairpin-shaped conductive hollow tube heater 12 made of an alloy such as Inconel, Hastelloy, or stainless steel is installed within a rectangular parallelepiped thermal insulation structure 11, extending from a saturated steam (or water) inlet 11a toward a closed end 11b. In this case, the hairpin-shaped conductive hollow tube heater 12 also has, for example, six straight sections 12-1 to 12-6 and five folded sections 12-7 to 12-11 that fold back the straight sections 12-1 to 12-6. A saturated steam-side electrode 13a equipped with a heat sink 13a-1 is installed on the saturated steam inlet 11a side of the hairpin-shaped conductive hollow tube heater 12, while a superheated steam-side electrode 13b equipped with a heat sink 13b-1 is installed on the closed end 11b side of the hairpin-shaped conductive hollow tube heater 12. When a DC or AC voltage V is applied between the saturated steam side electrode 13a and the superheated steam side electrode 13b, the hairpin-shaped conductive hollow-tube heater 12 is heated to, for example, approximately 700°C to 800°C, and the saturated steam P in the hairpin-shaped conductive hollow-tube heater 12 becomes superheated steam Q1 (=Q), which flows toward the closed end 11b. At this time, the superheated steam Q1 from the superheated steam discharge nozzle 12a in the hairpin-shaped conductive hollow-tube heater 12 is discharged downward through the opening in the heating plate 14. At the same time, the heating plate 14 is heated by radiant heat (far-infrared light) H1 from the hairpin-shaped conductive hollow-tube heater 12, and the far-infrared light H1 is discharged downward from the heating plate 14. In this case, the heating plate 14 is an iron plate, for example, stainless steel (SUS304), with the surface sintered with black ceramic, and a ceramic reflector 15 supported by a reflector stay 15a is provided above the heating plate 14 to increase the far-infrared light H1 from the heating plate 14. In this way, high-temperature heat treatment is possible using the combined heat of the superheated steam Q1 at, for example, 700°C to 800°C and the far-infrared light H1.

[0027] The temperature sensor (thermocouple) 16 is provided in the hairpin-shaped conductive hollow tube heater 12 and serves to control the temperature of the hairpin-shaped conductive hollow tube heater 12. That is, as described above, the control unit 5 detects the voltage V between the electrodes 13a and 13b and the temperature T1 of the temperature sensor 16 as a predetermined temperature T1. ０ For example, feedback control is performed so that the temperature is between 700°C and 800°C.

[0028] Next, the insulator structure of the hairpin-shaped conductive hollow tube heater 12 will be described with reference to Figure 5. The heater 12 includes a heat-resistant ceramic vertical holder 17 that slidably holds, for example, six straight sections 12-1 to 12-6 of the hairpin-shaped conductive hollow tube heater 12, stainless steel horizontal holders 18a and 18b that hold the ceramic vertical holder 17 from above and below, a stainless steel stay 19a that secures the horizontal holders 18a and 18b, and a stainless steel stay 19b that secures the horizontal holder 18b to the ceiling side of the stainless steel frame 113 via an upper insulating member 111. For ease of assembly, the ceramic vertical holder 17 is divided into eight holder pieces 17-1, 17-2, ..., 17-8. That is, the insulator structure is composed of ceramic vertical holders 17 (17-1, 17-2, ..., 17-8), horizontal holders 18a, 18b, and stays 19a, 19b. In this case, the ceramic vertical holder 17 has an opening with a diameter of, for example, 30 mm, which is larger than the diameter of the straight sections 12-1 to 12-6, for example, 20 mm. Therefore, even if the straight sections 12-1 to 12-6 of the hairpin-shaped conductive hollow-tube heater 12 thermally expand and contract, the straight sections 12-1 to 12-6 of the hairpin-shaped conductive hollow-tube heater 12 easily slide within the opening of the ceramic vertical holder 17, making them less likely to break. Note that the folded sections 12-7 to 12-11 of the hairpin-shaped conductive hollow-tube heater 12 also thermally expand and contract, but the amount of thermal expansion is smaller than that of the straight sections 12-1 to 12-6. However, if the folded portions 12-7 to 12-11 of the hairpin-shaped conductive hollow-tube heater 12 were firmly fixed, the thermal expansion and contraction of the straight portions 12-1 to 12-6 of the hairpin-shaped conductive hollow-tube heater 12 would be prevented, making the hairpin-shaped conductive hollow-tube heater 12 more susceptible to damage. Therefore, the folded portions 12-7 to 12-11 of the hairpin-shaped conductive hollow-tube heater 12 are left unconstrained.

[0029] 4, the heating plate 14 is provided, but the heating plate 14 may not be provided. In this case, the effect of the far-infrared light H1 is lost, and only the effect of the superheated steam Q1 remains.

[0030] Figure 6 shows a second example of the superheated steam generating unit of Figure 1, where (A) is a cross-sectional view and (B) is a view taken along line B-B in (A). The superheated steam generating unit of Figure 6 is a two-stage type for generating superheated steam at ultra-high temperatures of, for example, 1000°C to 1600°C.

[0031] In Figure 6, a two-stage superheated steam generating unit 1' is constructed by adding a superheated steam generating function to the superheated steam generating unit 1 of Figure 4. That is, an airtight rectangular parallelepiped heat insulating structure 11' is added, which is composed of a heat insulating material 111', a stainless steel frame 112' covering the heat insulating material 111', and a mounting plate 113' at the bottom of the heat insulating material 111'. Instead of the heating plate 14 provided at the open end OP1 of Figure 4, a heating plate 14' for passing superheated steam Q1 is provided at the upper open end OP2 of the rectangular parallelepiped heat insulating structure 11', and a heating plate 14" is provided at the lower open end OP3 of the rectangular parallelepiped heat insulating structure 11'. In this case, the superheated steam discharge nozzle 12a passes through the opening of the heating plate 14' and enters the rectangular parallelepiped heat insulating structure 11'. In addition, a heating plate 14" made of, for example, molybdenum disilicide (MoSi ２4. In this case, the high-temperature heater 12' has a suspended S-shape that extends in the direction of the flow of the superheated steam Q1 and the far-infrared light H1, and therefore the thermal conductivity of the high-temperature heater 12' to the superheated steam Q1 and the far-infrared light H1 is increased. Therefore, when a DC or AC voltage V' is applied between the electrodes 13'a and 13'b, the high-temperature heater 12' is heated, and the superheated steam Q1 in the rectangular parallelepiped heat insulating structure 11' becomes superheated steam Q2 at a higher temperature, for example, 1000°C to 1600°C, and the superheated steam Q2 flows toward the heating plate 14". As a result, the superheated steam Q2 (=Q) is sent downward from the opening of the heating plate 14". At the same time, the heating plate 14' is heated by radiant heat (far-infrared light) H1 from the hairpin-shaped conductive hollow tube heater 12, and the far-infrared light H1 from the heating plate 14' is sent downward from the heating plate 14". In this case, the heating plates 14', 14" are made of a high-temperature heat-resistant material, such as tungsten (W), molybdenum (Mo), or ceramic with its surface sintered into blackbody ceramic. In this way, ultra-high temperature heat treatment is possible using the combined heat of the superheated steam Q2 at, for example, 1000° C. to 1600° C. and the far-infrared light H2.

[0032] The temperature sensor (thermocouple) 16' is provided in the high-temperature heater 12' and is used to control the temperature of the high-temperature heater 12'. That is, the control unit 5 detects the voltage V' between the electrodes 13'a and 13'b and the temperature T1' of the temperature sensor 16' at a predetermined temperature T1 ０ For example, feedback control is performed to keep the temperature between 1000°C and 1600°C.

[0033] Although the heating plate 14'' is provided in FIG. 6, the heating plate 14'' may not be provided. In this case, the effect of the far-infrared light H2 is lost, and only the effect of the superheated steam Q2 remains.

[0034] FIG. 7 is a front view showing a second embodiment of the waste gas treatment device according to the present invention.

[0035] In FIG. 7, a catalyst unit 6 is provided in place of the condensation and liquefaction unit 4 in FIG.

[0036] 7, the pyrolyzed dry distillation gas G2 in the pyrolysis chamber 3 is not condensed or liquefied, but is detoxified by the catalyst in the catalyst unit 6 and then released into the atmosphere. That is, the catalyst unit 6 is provided with a highly active, highly selective and long-life catalyst for detoxifying light residual toxic gases in the dry distillation gas G2, such as lower hydrocarbons such as methane gas, ethane gas, and butane gas. That is, the light hydrocarbons in the waste gas, such as methane gas, ethane gas, propane gas, and butane gas, are detoxified at high temperatures to produce harmless carbon dioxide (CO ２ ) and water (H ２ The oxidation catalyst is provided with an oxidation catalyst that converts HCl into O. The support for the oxidation catalyst is a pellet support or a honeycomb support, and for example, platinum (Pt) or palladium (Pd) is used. Note that other catalysts may be provided as needed.

[0037] The operation of the waste gas treatment device of FIG. 7 is also performed according to the flowchart of FIG. 3, but in step 306, only the superheated steam generating unit 1 is started up.

[0038] While the high-temperature heater 12' in Figure 6 is provided in the superheated steam generating unit 1', as shown in Figure 8(A), a high-temperature heater 32 can be provided in the pyrolysis chamber 3 instead of the high-temperature heater 12'. In this case, the single-stage type of Figure 4 is used as the superheated steam generating unit, and the high-temperature heater 32 is a flat S-shaped heater (for example, a SUPERTHAL flat panel, registered trademark of Sandvik K.K.) that is parallel to the flow of the waste gas G1, as shown in Figure 8(B), to facilitate heat conduction to the waste gas G1. The high-temperature heater 32 has electrodes 32a and 32b and is constructed on ceramic fiber 33. The high-temperature heater 32 is also provided with a temperature sensor (thermocouple) 34. Therefore, the control unit 5 measures the voltage between the electrodes 32a and 32b when the temperature T3 of the temperature sensor 34 reaches a predetermined value T3 ０ For example, feedback control is performed so that the temperature is between 1000°C and 1600°C.

[0039] The present invention can be applied to any modifications within the scope of the above-described embodiment.

[0040] 1: Superheated steam generating unit 11a: Saturated steam inlet 11b: Closed end 11: Rectangular heat insulating structure 111: Heat insulating material 112: Joint material 113: Stainless steel frame 114: Handle 115: Mounting plate 11a: Saturated steam inlet 11b: Closed end 12: Hairpin-shaped conductive hollow tube heater 12-1 to 12-6: Straight section 12-7 to 12-11: Folded section 12a: Superheated steam discharge nozzle 13a: Saturated steam side electrode 13a-1: Heat sink 13b: Closed end side electrode 13b-1: Heat sink 14, 14': Heating plate 15: Reflector 15a: Reflector stay 16: Temperature sensor 17: Vertical holder 17-1, 17-2, ..., 17-8: Holder pieces 18a, 18b: Horizontal holder 19a, 19b: Stay 2: Saturated steam generation unit 2a: Solenoid valve 3: Pyrolysis chamber 3a: Waste gas inlet 3b: Dry distillation gas outlet 32: High-temperature heater 32a, 32b: Electrodes 33: Ceramic fiber 34: Temperature sensor 4: Condensation liquefaction unit 41: S-shaped heat exchanger 41a: Dry distillation gas inlet 41b: Condensed liquefied gas outlet 42: Water tank 42a: Water supply port 42b: Drain 43: Water temperature conditioning unit 43a: Refrigerant pipe 44: Fan 44a: Motor 5: Control unit 6: Catalytic unit 1': Superheated steam generation unit 11': Rectangular heat insulation structure 111': Heat insulation material 112': Stainless steel frame 113': Mounting plate 12': High-temperature heater 13a', 13b': Electrodes 13a-1: Heat sink 14": Heating plate 16': Temperature sensor P: Saturated steam (or water) Q, Q1, Q2: Superheated steam H1, H2: Far infrared light G1: Waste gas G2: Dry distillation gas

Claims

1. A waste gas treatment device comprising: a superheated steam generating unit (1, 1'); and a thermal decomposition chamber (3) provided below the superheated steam generating unit (1, 1') for thermally decomposing a waste gas (G1) using the superheated steam (Q) from the superheated steam generating unit.

2. The waste gas treatment device according to claim 1, further comprising a condensation and liquefaction unit (4) for condensing and liquefying the carbonization gas (G2) from the pyrolysis chamber (3) and recovering it.

3. The waste gas treatment device according to claim 2, wherein the condensation and liquefaction unit (4) comprises: a heat exchanger (41) having a pyrolysis gas inlet (41a) connected to the pyrolysis gas outlet (3b) of the pyrolysis chamber (3) and a condensed liquid outlet (41b); a water tank (42) for accommodating the heat exchanger (41); a water temperature conditioning unit (43); and a refrigerant pipe (43a) connected to the water temperature conditioning unit (43) and provided in the water tank (42).

4. The waste gas treatment device according to claim 1, further comprising a catalytic unit (6) for catalytically treating the carbonization gas (G2) from the pyrolysis chamber (3).

5. The waste gas treatment device according to claim 4, wherein the catalytic unit (6) contains catalysts (61, 62, 63, 64) for detoxifying residual toxic gases in the dry distillation gas (G2).

6. The superheated steam generating unit (1) comprises: a first heat insulating structure (11) having a saturated steam inlet (11a) or a water inlet and a closed end (11b) and a first open end; a hairpin-shaped conductive hollow tube heater (12) provided in the first heat insulating structure (11) between the saturated steam inlet (11a) or the water inlet and the closed end (11b) and consisting of a plurality of straight portions (12-1 to 12-11) and a plurality of folded portions (12-7 to 12-11) folding back the straight portions (12-1 to 12-6); and a superheated steam discharge nozzle (12a) provided midway in the hairpin-shaped conductive hollow tube heater (12) for discharging superheated steam (Q1) in the hairpin-shaped conductive hollow tube heater (12) toward the first open end (OP1). and an insulator structure (17, 18a, 18b, 19a, 19b) provided between the first thermal insulation structure (11) and the straight portions (12-1 to 12-6) of the hairpin-shaped conductive hollow tube heater (12), for slidably holding the straight portions (12-1 to 12-6).

7. The waste gas treatment device according to claim 6, wherein the insulator structure (17, 18a, 18b, 19a, 19b) has an opening with a diameter larger than the diameter of the straight portions (12-1 to 12-6) and is provided with a heat-resistant holder (17) for passing the straight portions (12-1 to 12-6).

8. The waste gas treatment device according to claim 6, further comprising a first heating plate (14) provided at said first open end (OP1) and having an opening for passing said superheated steam discharge nozzle (12a).

9. The waste gas treatment device according to claim 6, wherein the folded portions (12-7 to 12-11) are in an unconstrained state.

10. The waste gas treatment device according to claim 6, further comprising: a second heat insulating structure (11') having a second open end (OP2) connected to the first open end (OP1) of the first heat insulating structure (11) and a third open end (OP3) opposite the second open end (OP2); and a high-temperature heater (12') provided within the second heat insulating structure (11') and having a higher temperature than the hairpin-shaped conductive hollow tube heater (12).

11. The waste gas treatment device according to claim 10, further comprising a second heating plate (14') provided at the second open end (OP2) of the second thermal insulation structure (11') and having an opening for passing the superheated steam discharge nozzle (12a).

12. The waste gas treatment device according to claim 10, wherein said high temperature heater (12') is of a suspended S-shape.

13. The waste gas treatment device according to claim 11, wherein said high temperature heater (12') is provided on said second heating plate (14').

14. The waste gas treatment device according to claim 10, further comprising a third heating plate (14") provided at the third open end (OP3) of the second insulating structure (11') and having an opening for passing the superheated steam (Q2).

15. The waste gas treatment device according to claim 6, further comprising a high temperature heater (32) provided within said pyrolysis chamber and having a temperature higher than that of said paired-pin conductive hollow tube heater (12).

16. The waste gas treatment device according to claim 15, wherein said high temperature heater (32) is flat S-shaped.

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