JP2002267135A - Method for burning and decomposing polybiphenyl chloride and high-temperature incinerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress occurrence of dioxins or the like in a combustion exhaust gas when PCB is burned and decomposed by a burner. SOLUTION: A method for burning and decomposing a polybiphenyl chloride comprises the steps of mixing a reducing water having a lowered oxidation- reduction potential of -100 to -2,500 mV of 5 to 20% by volume with a liquid fuel containing the PCB and a liquid-like hydrocarbon, pressure-reducing, boiling, emulsifying the mixture, and then burning the mixture by a main burner 24 of a first combustion chamber 18. The method further comprises the steps of ejecting an air flow or a combustion flame from a first mixing burner 26 to the flame of the burner 24 to form a mixture flow, introducing the mixture flow to a second combustion chamber 20 via a throttle unit 16, ejecting a flame from a second mixing burner 28, and bringing about a mixture secondary combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for combusting and decomposing PCB (polychlorinated biphenyl) and a mixed waste of PCB and oil at a high temperature and treating it as harmless exhaust gas, and a high-temperature incineration apparatus for the PCB. .

[0002]

2. Description of the Related Art PCBs are chemically stable compounds, and it is estimated that about 1.2 million tons were produced worldwide for applications such as heat transfer media, insulating oils, plasticizers, lubricating oils, and paints.

[0003] PCB is a generic term for those obtained by replacing hydrogen in a biphenyl structure with chlorine, and there are theoretically 209 compounds depending on the number and position of the substituted chlorine. More than 100 types of PCBs have been confirmed in actual commercial products, and all commercially available PCBs are mixtures of single PCBs.

[0004] It became clear that PCBs caused serious pollution with the increase in usage, and in Japan, production and use were banned in 1972, after which they were designated as specific chemical substances and required strict management. .

[0005] However, PCB is a very stable compound and generates dioxin by incineration, so that it is difficult to perform safe treatment, and a large amount of untreated PCB remains.

In Japan, strict management is required by the law of the 1990 revision, but the cost burden for storage is such as fires and earthquakes in storage facilities, accidents during transportation, risks to nearby residents due to volatilized PCBs, etc. Is large (10% of processing cost)
There is a demand for the development and commercialization of a technology for actively decomposing this.

Conventionally, three types of PCB decomposition techniques have been studied: incineration, physicochemical treatment, and biochemical treatment (bioremediation).

[0008] Of these, physicochemical treatment (dechlorination with a catalyst, photodecomposition, decomposition with supercritical water, etc.) and biochemical treatment (decomposition of chemical substances by microorganisms) are still in the research stage. take time.

The most practical application is incineration treatment at high temperature, which is currently performed at 1150 ° C., test residence time of sprayed PCB in the furnace for 2 seconds, excess oxygen of 3%, and decomposition efficiency of 99.99999% ( 6-Nine), the PCB processing is legally permitted.

[0010] The only device in Japan that has been put into practical use in PCB incineration treatment is a P-type device on the circumference of the head of a horizontal cylindrical cracking furnace.
A three-fluid burner that supplies a mixture of CB and kerosene is arranged so that the droplets do not interfere with each other, and a PCB that has been atomized to a maximum diameter of 150 μm by the burner is
The spray combustion is performed in a high temperature atmosphere of about 1450 ° C.

In this cracking furnace, the combustion gas flows spirally in a cylindrical furnace in order to improve the mixing, and after a residence time of 2.5 seconds or more, the combustion gas is pushed downstream of the furnace, and the exhaust gas is recombined with dioxin. Is configured to be instantaneously cooled in water after exiting the furnace to minimize

In this cracking furnace, about 55 years of waste PCB is used for about 2 years.
00 tons were treated with a pyrolysis efficiency of 99.9999999% (8-nine).

However, this cracking furnace is difficult to operate and control because it burns at a high temperature, and the unashed PCB is contained in the ash. If there is a portion where the temperature is low, there is a problem that there is a risk of generating coplanar PCB and dioxin which are more toxic than PCB.

Here, the current environmental standards and emission standards for dioxins are 0.1 ng-TEQ / m in the case of a large furnace having a raw material processing capacity of 1 t / h or more in the atmospheric emission standard.
3N, 1ng-TEQ / m3N for medium furnace, 5n for small furnace
g-TEQ / m3N, which is 10 p
g-TEQ / l.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and greatly reduces the amount of dioxin (including undecomposed PCB) in exhaust gas. It is an object of the present invention to provide a method for burning and decomposing PCB, and a high-temperature incinerator for PCB, which can achieve 99.999999% (8-nine).

[0016]

SUMMARY OF THE INVENTION The inventor of the present invention disclosed in Japanese Patent Application No. 11-138412 that water whose oxidation-reduction potential was lowered by electrolysis in a liquid fuel composed of, for example, heavy oil (Japanese Patent No. 2623204). The present invention has proposed that dioxins in combustion exhaust gas can be greatly reduced by mixing the mixture and boiling the mixture under reduced pressure to form a so-called emulsion and then burning.

The present invention is based on the results of the research conducted by the present inventor, and a part of the heavy oil is replaced with PCB, and the mixed P is mixed due to the complete combustion effect by emulsification.
CB is also intended to be completely decomposed and burned.

The ultrafine particles of the liquid fuel by emulsification have the same effect on the PCB mixed at a certain rate, and the PCB mixed together with the liquid fuel is also converted into ultrafine particles, which are decomposed and burned. Travels at approximately the same speed as the liquid fuel.

According to the present invention, a liquid fuel containing polychlorinated biphenyl and liquid hydrocarbon has a redox potential of -100.
~ 2500 mV of reduced water reduced to
The above object is achieved by a method of burning and decomposing polychlorinated biphenyl, which comprises mixing 20% of the mixture, boiling the mixture under reduced pressure, emulsifying the mixture, and burning the mixture. .

Further, reduced water and liquid hydrocarbons whose oxidation-reduction potential has been lowered to -100 to 2,500 mV are mixed with the combustion gas of the liquid fuel, and the mixture is boiled under reduced pressure to form an emulsion, followed by spraying. The combustion may be performed while causing turbulent diffusion mixing with the above.

Further, air may be blown into the combustion gas of the liquid fuel to cause turbulent diffusion mixing, thereby burning the unburned fluid fuel.

Furthermore, the cross-sectional area of the discharge flow of the combustion gas of the liquid fuel is reduced to 1/4 or less, and then the cross-sectional area of the discharge flow is increased to expand and discharge the combustion gas. Is also good.

Also, reduced water and a liquid hydrocarbon whose oxidation-reduction potential has been lowered to -100 to -2500 mV are mixed with the expanded combustion gas, and the mixture is boiled under reduced pressure to form an emulsion, followed by spraying. The combustion may be performed while causing turbulent diffusion mixing with the combustion gas.

Further, the combustion gas in which the turbulent diffusion mixing has occurred may be kept at 1400 ° C. or more for 1 to 2 minutes.

Further, the reduced water comprises a first electrode, a second electrode, and a third electrode arranged in water, and the first and second electrodes are made of one of aluminum and magnesium for lowering the oxidation-reduction potential. And applying an alternating current between the first and second electrodes and grounding the third electrode, so that a direct current flows from the first and second electrodes to the third electrode via the water. And water may be electrolyzed to form water.

The liquid hydrocarbon may be any of heavy oil, kerosene, light oil, waste oil, alcohol or dimethyl ether.

According to the present invention, a liquid fuel containing polychlorinated biphenyl and liquid hydrocarbon has a redox potential of -100.
~ 2500 mV of reduced water reduced to
A fuel supply device for supplying a 20% mixed fuel mixture, a decompression device for decompressing and boiling the supplied mixed fuel, and a constricted portion having a cylindrical shape with both ends covered and provided at an intermediate portion in the longitudinal direction. A furnace body divided into a first combustion chamber and a second combustion chamber; and a furnace body attached to an upper end plate at an upper end of the first combustion chamber in the furnace body, supplied from the fuel supply device through the pressure reducing device, and depressurized. A first burner that forms a flame by burning the mixed fuel at least partially vaporized by boiling, and a first mixing unit that includes a substantially half region of the first combustion chamber on the first burner side. The mixed fuel which is attached to the peripheral wall obliquely toward the upper head plate and is supplied from the fuel supply device through a compressed air flow or the decompression device and at least partially vaporized by decompression boiling. At least one first mixing burner capable of selectively forming one of the flames due to combustion, and a peripheral wall of a second mixing section of the second combustion chamber, which is constituted by a substantially half area on the throttle section side, At least one second mixing burner that is mounted obliquely toward the throttle portion and that is supplied from the fuel supply device through the pressure reducing device and that forms a flame by burning the mixed fuel at least partially vaporized by reduced pressure boiling; And a secondary combustion section comprising the remaining area of the second mixing section of the second combustion chamber for retaining combustion gas for a certain period of time; and a gas exhaust provided on a lower end plate at a lower end of the second combustion chamber. The above object is attained by a high temperature incinerator for polychlorinated biphenyl having an outlet.

Further, the flame from the burner and the flame or air flow from the first mixing burner are mixed from the remaining area of the first mixing section of the first combustion chamber to promote turbulent diffusion mixing. A primary combustion section may be formed.

Further, the gas passage cross-sectional area of the throttle portion may be not more than １ ／ of the gas passage cross-sectional area of the first and second combustion chambers before and after this.

Furthermore, first, second, and third electrodes are arranged in water, and the first and second electrodes are made of a metal that reduces the oxidation-reduction potential as the first and second electrodes. By applying an alternating current between the electrodes and grounding the third electrode, a DC current is passed from the first and second electrodes to the third electrode via the water to electrolyze the water. A reduced water producing apparatus for supplying the reduced water to the fuel supply apparatus may be further provided.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, a high-temperature incinerator 10 of polychlorinated biphenyl (hereinafter referred to as “PCB”) according to an embodiment of the present invention converts oxidized liquid fuel containing PCB and liquid hydrocarbons such as heavy oil into oxidized fuel. Reduction potential of -100 to -2500
a fuel supply device 12 for supplying a mixed fuel in which the reduced water reduced to mV is mixed at a volume ratio of 5 to 20%, a pressure reducing device 14 for reducing the pressure of the supplied mixed fuel under reduced pressure (see FIG. 3), A furnace body 22 having a closed cylindrical shape, the inside of which is divided into a first combustion chamber 18 and a second combustion chamber 20 by a throttle 16 provided at an intermediate portion in the longitudinal direction, and the first combustion in the furnace body A flame is formed by the combustion of the mixed fuel, which is attached to the upper end plate 19 at the end (upper end) of the chamber 18 and is supplied from the fuel supply device 12 through the pressure reducing device 14 and at least partially vaporized by the reduced pressure boiling. To the upper end plate 19 on the main burner 24 and the peripheral wall 22A of the first mixing section 18A composed of a substantially half area of the first combustion chamber 18 on the main burner 24 side. 2 which is capable of selectively forming one of a compressed air flow or one of the flames produced by the combustion of the mixed fuel which is supplied from the fuel supply device 12 via the pressure reduction device 14 and at least partially vaporized by the reduced pressure boiling. First mixing burners 26, 26 and the second combustion chamber 20
Of the fuel supply device 12 is attached to the peripheral wall 22A of the second mixing section 20A, which is constituted by a substantially half area on the throttle section 16 side, toward the throttle section 16, and is provided through the pressure reducing device 14. Two second mixing burners 28, 28, which form a flame by combustion of the mixed fuel at least partially vaporized by reduced-pressure boiling, and
A secondary combustion section 20B for remaining the combustion gas for a certain period of time, which is composed of the remaining area (lower half) of the second mixing section of the combustion chamber 20, and an end (lower end) of the second combustion chamber 20 A gas outlet 30 provided in the lower end plate (bottom) 21 of
It is configured with.

The first mixing section 1 of the first combustion chamber 18
The remaining area (lower half) of 8A mixes the flame from the main burner 24 with the flame or air flow from the first mixing burner 26 to promote a primary combustion section 18B that promotes turbulent diffusion mixing. Has formed.

The throttle section 16 has an area smaller than 1/4 of the inner cross-sectional area of the first and second combustion chambers 18 and 20 before and after it, that is, the cross-sectional area of the passage of the combustion gas. .

The fuel supply device 12 includes a waste PCB from a waste PCB tank 32, a liquid fuel formed by adding liquid hydrocarbons from a fuel tank 34 by a line mixer 35 as necessary, and a reduced water producing device. The reduced water formed at 36 is mixed and supplied to the main burner 24 as a mixed fuel. Also, fuel tank 3
4 and the reduced water from the reduced water producing device 36 can be supplied to the first and second mixing burners 26 and 28.

The two first mixing burners 26, 26
Is provided on the peripheral wall 22A at a position facing 180 ° so as to form a rotational flow obliquely inward in the circumferential direction and upward, and two second mixing burners 28, 28
The first mixing burners 26, 26 are provided on the peripheral wall 22 </ b> A so as to face 180 ° at an orientation different by 90 °.

Reference numeral 23 in the figure denotes a jacket that surrounds the outer periphery of the furnace main body 22 and in which cooling water is introduced.

In FIG. 1, reference numerals 38A and 38B represent
Shown are temperature sensors disposed below the first combustion chamber 18 and below the second combustion chamber 20, respectively. This temperature sensor 38
The detection signals of A and 38B are output to a controller 40 (see FIG. 2), and the controller 40 controls the temperature of the combustion gas in the lower part of the first combustion chamber 18 and the lower part of the second combustion chamber 20 to a set value. PC to be supplied to the main burner 24
B, the mixture ratio of liquid hydrocarbon and air is controlled, and the first mixture burner 26 is configured to eject only air or mix the liquid hydrocarbon with air to supply the first mixture burner, The second mixing burner 28 can control the supply amount of the liquid fuel and the mixing ratio of the liquid fuel and the air.

Next, the detailed structure of the main burner 24 and the first and second mixing burners 26 and 28 will be described with reference to FIGS. Here, since these burners have the same shape, description of the first and second mixing burners 26 and 28 will be omitted by describing the main burner 24.

This main burner (hereinafter, burner) 24
Is provided with a cylindrical outer nozzle 52 having an outer nozzle opening 52A at a tip thereof, and disposed inside and coaxial with the outer nozzle 52, and provided at the tip with the outer nozzle opening 52A.
And an inner nozzle 54 having an inner nozzle opening 54A that is open at a position close to the inner side in the axial direction, and is provided in the inner nozzle 54 toward the inner nozzle 54. From the decompression device 14, the mixed fuel partially or wholly vaporized by decompression boiling is ejected from the inner nozzle opening 54A and mixed with the air supplied to the annular space 53 between the outer nozzle 52 and the inner nozzle 54, The jet is ejected from the outer nozzle opening 52A, and the jet is ignited and burned.

Reference numeral 58 in FIGS. 1 to 3 denotes an air pump for pressurizing and supplying air to the annular space 53 between the outer nozzle 52 and the inner nozzle 54 via the flow control valve 24A. The fuel supply device 12 includes a flow control valve 61 for supplying the liquid fuel from the line mixer 35 to a base end of the inner nozzle 54 opposite to the inner nozzle opening 54A.

The liquid fuel from the fuel tank 34 and the reduced water from the reduced water producing device 36 are supplied to the flow control valve 26A,
The mixture is supplied to the first and second mixing burners 26 and 28 via 28A.

Further, the air pump 58 is connected to the flow control valve 2.
6B, 28B, the first and second mixing burners 26, 2
8 can be supplied with compressed air.
As shown in FIG. 2, the flow control valves 24A, 26
A, 26B, 28A, 28B, 61 are controlled by the control device 40.

The inner nozzle 54 includes a nozzle 55A having the inner nozzle opening 54A,
5A, an intermediate tubular portion 55B screwed to the proximal end thereof, and a fuel supply pipe 55 screwed to the proximal end side of the intermediate tubular portion 55B.
C through the center of the fuel passage 6
4 are formed.

The pressure reducing device 14 includes a fuel reservoir 66 formed in the middle of the fuel passage 64 and a fuel reservoir 66.
The fuel reservoir 66 is divided into the inner nozzle opening 54A side and the fuel cylinder 60 side, and is provided with a pressure reducing plate 68 in which these are communicated by a large number of small holes 68A.

The fuel reservoir 66 is provided with the intermediate cylinder 55B.
Is formed between the base end of the fuel supply pipe 55C and the front end of the fuel supply pipe 55C, the pressure reducing plate 68 is screwed to the outside of the base end of the intermediate cylinder 55B, and the front end of the fuel supply pipe 55C is connected to the intermediate cylinder 55B.
The pressure reducing plate 68 is screwed to the outer periphery on the base end side.

As shown in an enlarged view in FIG. 4, the pressure reducing plate 68 has a truncated cone shape protruding in the base end direction of the inner nozzle 54, and the liquid supplied from the flow control valve 61 to the base end of the inner nozzle 54. When the mixed fuel of No. 1 is drawn out toward the inner nozzle opening 54A through the fine hole 68A, the mixed fuel is depressurized and boiled.

The reference numeral 70 in FIG.
Shown is a jet ring attached to the tip of nozzle 55A to form 4A.

The outer nozzle 52 comprises a nozzle portion 53A having an outer nozzle opening 52A formed therein, and a cylindrical portion 53B to which the base end of the nozzle portion 53A is screwed. Air supply pipe 59 for introducing air from air pump 58 via air joint 59A
B is screwed.

Reference numeral 72 in FIG.
5 shows centering attached and fixed between the nozzle portion 53A and the cylindrical portion 53B when they are screwed together. The centering 72 supports the vicinity of the distal end of the intermediate cylindrical portion 55B of the inner nozzle 54 from the outside, and positions the inner nozzle 54 coaxially with the outer nozzle 52.

The centering 72 is provided on the intermediate cylindrical portion 5.
The mounting groove 73 extends in the axial direction from the tip of 5B and is bent at a right angle to the mounting groove 73 formed in an angle range of about 30 °.
Inserted in the axial direction and rotated in the circumferential direction, it is fitted in the intermediate cylindrical portion 55B.

The outer nozzle 52 containing the inner nozzle 54 is disposed on the center axis of an outer air supply pipe 76 to which air from an air blower (not shown) is supplied.

The reduced water to be mixed with the liquid fuel is produced by a method disclosed in, for example, Japanese Patent No. 2623204.

That is, as shown in FIG. 5, the reduced water producing apparatus 36 includes first, second, and third electrodes 82A, 82B, and 82C provided in a container 80 containing water. Electrode 82C is grounded, and the first and second electrodes 82A, 82A
A high-frequency alternating current of 20 Hz or more at a voltage of 10 V to 200 V is applied to B alternately by the operation of the first and second high-frequency switches 84A and 84B, so that the third and fourth electrodes 82A and 82B A direct current is passed through the electrode 82C through the water, and the reduced water is formed by electrolyzing water between the electrodes.

Here, the first and second electrodes 82A, 82A
2B lowers the oxidation-reduction potential, for example lithium,
Zinc, magnesium, iron, stainless steel, aluminum,
It is made of metal such as copper.

When the oxidation-reduction potential of water is reduced to about −100 mV to −2500 mV by such electrolysis, as described in the aforementioned Japanese Patent No. 2623204, the detergency of water increases. It has been known that organic compounds are made harmless. However, the present inventor has found that mixing this reduced water having a reduced oxidation-reduction potential with a liquid fuel such as heavy oil and burning it results in the reduction of dioxins in the combustion exhaust gas. It has been discovered that the occurrence can be greatly reduced.

The mixing ratio of the reduced water to the liquid fuel is preferably about 5 to 20% by volume. In addition, the reduced water is 5
When the amount is less than 20%, the effect is small. When the amount exceeds 20%, the effect is reduced. When the amount is 15%, the effect of reducing dioxin is the maximum. The dioxin reduction effect is small when the oxidation-reduction potential is larger than -100 mV, and is larger as the oxidation-reduction potential is smaller, but the minimum voltage in the current technology is -2500 mV.

The reduced water may be prepared in advance and mixed with a liquid fuel. The reduced water is produced by the reduced water producing device 36 including the first to third electrodes 82A to 82C as described above. You may make it supply to the said fuel supply apparatus or the mixing burner, continuously producing reduced water.

Next, a process (method) of burning and decomposing waste PCB by the above PCB high-temperature incinerator 10 will be described.

There are about 100 types of commercially available PCBs, and waste PCBs to be treated normally are often mixtures with other types of oils.

For example, what has been used as a heating medium is a biphenyl tetrachloride containing oils such as kerosene, the PCB concentration of which is 50 to 75%, and the chlorine concentration of which is 30 to 75%.
40%, calorific value 6000-7000 kcal / kg
It is.

Here, a description will be given by taking biphenyl tetrachloride as an example of PCB.

When 4-chlorobiphenyl is heated to a high temperature and completely burned in air, it is decomposed into carbon dioxide, hydrogen chloride and water vapor as follows.

C12H8Cl4 + 12.5O2 = 12CO2 +
4HCl + H2O

Further, assuming that the oils contained in the waste PCB are equivalent to heavy oil, and the components thereof are 85% by weight of carbon (C) and 15% by weight of hydrogen (H), the theoretical air per kg of oil can be obtained. The amount used was 11.6 m3 N / kg, and the exhaust gas molar composition after theoretical combustion was 12.9% for CO2, 13.4% for H2O,
N2 is 73.7%.

Since the quantity and type of oils mixed in the waste PCB cannot be known in advance, the PCB incinerator must be compatible with any waste PCB.

In the PCB high-temperature incinerator 10, the amounts of the waste PCB and the liquid hydrocarbons sent to the main burner 24 can be freely controlled by the control device 40. For example, in the case of a 100% PCB waste PCB treatment, a corresponding liquid hydrocarbon can be added, and the temperature can be freely controlled by referring to the temperature sensors 38A and 38B in the apparatus according to the PCB concentration of the waste PCB.

Here, the case where the PCB concentration of the waste PCB is a heavy oil equivalent oil in which the PCB concentration is 60% by weight and the mixed oils are 40% by weight will be described as an example.

In this case, it is not necessary to newly add liquid fuel to the waste PCB sent to the main burner 24.
Burn as it is.

Assuming that this waste PCB has a calorific value of 6000 kcal / kg, if it is completely burned with a theoretical air amount, the molar composition of exhaust gas generated by decomposition and combustion of PCB and combustion of oils is CO2 15.1%, H2O 9.0
%, N2 is 73.6%, HCl is 2.3%, and the theoretical flame temperature is 1950 ° C.

In the study on the rate of thermal decomposition of PCB,
D. S. There is a paper by Davali et al.
It is reported that thermal decomposition starts in seconds, and 99.9% of decomposition occurs at 800 ° C. for 1 second. But 99.999
Under these conditions, it is insufficient to cause 999% (8-nine) decomposition.
At 0 ° C., about 1/100 second is required.

Accordingly, in order to decompose the entire amount of waste PCB sent into the apparatus as described above, there are two problems, namely, how to make the liquid PCB finer uniformly and how to make the whole inside of the furnace a uniform high temperature. There is.

If any part of the furnace has a poor heat transfer in the particle size, it may be discharged without decomposition, and if a part of the furnace has a low-temperature part, the same applies.

Therefore, it is essential that sufficient atomization by the burner and a sufficiently high temperature distribution in the furnace be essential. In the apparatus of the present invention, it is possible to cope with various types of waste PCB compositions.
The main burner 24, which is an emulsion burner using the reduced water, the first mixing burner 26, has a sufficient turbulent diffusion and complete mixing structure due to collision and throttling in the furnace, and a secondary mixing burner 28 Obtain sufficient furnace residence time, including the combustion zone, to completely incinerate the PCB.

This method of combusting and decomposing PCB is characterized in that reduced water is used as a fluid for emulsifying and emulsifying a fuel containing PCB, and the inherent effect of emulsion combustion is that a wide area of fuel due to rapid expansion and evaporation of water is used. Dispersion-wide-angle flame formation, but the use of reduced water with extremely low surface tension results in widespread diffusion of ultra-fine particles of water into the furnace, resulting in uniform combustion chamber temperature, decomposition, and burning rate. Decomposition and combustion can be achieved even with a slow PCB.

The waste PCB is mixed with the liquid hydrocarbon by a line mixer 35 outside the furnace, and further reduced water is added thereto and introduced into a burner inner pipe of the main burner 24.

In this case, depending on the waste PCB, 50 to 70
It is necessary to lower the viscosity by heating to ℃ to facilitate the emulsification with reduced water.

If the waste PCB already contains a considerable amount of liquid hydrocarbons, there is no need to mix new liquid hydrocarbons, and 5-20% of the reduced water is directly mixed into the waste PCB.

In this main burner 24, waste P
When a mixed fuel obtained by mixing CB or waste PCB and a liquid fuel composed of a liquid hydrocarbon such as heavy oil and the reduced water flows out of the pores 68A of the pressure reducing plate 68 in the fuel reservoir 66, the boiling under reduced pressure occurs. It is vaporized and becomes fine particles, and is ejected with pressure from the jet ring 70 at the tip of the inner nozzle 54. At this time, the mixture is well mixed with the air pumped from the air pump 58 and ignites and burns.

The combustion flame ejected from the outer nozzle 52 is further mixed with the air from the outer air supply pipe 76 to completely burn the combustion flame.
The first combustion chamber 1 rides on the airflow from the output opening 76A at the tip.
8 flows into.

Since the output opening 76A is formed in a tapered shape expanding forward, the flame is radiated short and wide.

The main burner 24 is operated under the same conditions in a region close to the theoretical combustion air amount. At the burner outlet, the maximum combustion temperature is reached. In addition to the shape of the output opening 76A, the main burner 24 is operated by emulsion combustion using reduced water. A short and wide flame is formed, and the flame length is substantially inside the upper end plate 19.

The first and second mixing burners 26 and 28 are mounted with a slight upward inclination so that the overall air excess ratio is 2%.
Normally, only air is introduced so as to be about 0%.

About half of the upper part of the furnace surrounded by the burners 24 and 26 is a high-temperature primary mixing section 18A. The vortex caused by the collision of airflow with the upper wall of the furnace and swirling, and the two first mixing burners 26 and
The turbulent diffusion mixing is promoted by mixing with the air flow by 26, and almost all (99.99% or more) of the supplied waste PCB is decomposed and burned together with the effect of the reduced water.

By introducing air from the two first mixing burners 26, 26, a theoretical flame temperature of about 1900 ° C.
The temperature is lowered to about 0 ° C. and introduced into the primary combustion section 18 </ b> B in the lower half of the first combustion chamber 18.

In the primary combustion section 18B, the undecomposed PCB in the combustion gas is further decomposed and introduced into the throttle section 16 at the center of the furnace. The first combustion chamber 18 has a residence time of 1 to 2 minutes.
The amount of liquid fuel to be sent to the burner 24 by the controller 40 and the first mixing burner 26
However, when the furnace temperature is low, liquid fuel and reduced water can be introduced into the first mixing burner 26 to perform emulsion combustion.

In the narrowing section 16, a heat insulating material is applied so that the furnace cross-sectional area becomes about 1/4 or less, and the combustion gas exiting the primary burning section 18B is passed. The unevenness of the gas concentration is expanded into the throttle section 16 and the second combustion chamber 20 so as to be mixed and uniform, and is introduced into the lower secondary mixing section 20A.

In the first combustion chamber 18 in the upper part of the furnace, heat loss compensation from the furnace wall and temperature uniformity can be achieved by controlling the amount of liquid fuel supplied to the first mixing burner 26. However, heat loss compensation in the lower part of the furnace is possible. Therefore, in order to compensate for the heat loss and to allow the combustion gas from the upper portion to pass through the high-temperature flame zone again, the second mixing burner 28 is disposed at the lower portion of the throttle section 16 with an orientation different from the first mixing burner 26 by 90 °. , 28 are provided.

Like the first mixing burners 26, 26, the second mixing burners 28, 28 are mounted with a slight upward inclination so that the wide-area short flame length of the reduced water emulsion extends to the furnace center line. The gas that has exited from the throttle section 16 is supplied to the second mixing burner 2 at the furnace center in the secondary mixing section 20A.
It passes through 8, 28 flame zones and is mixed.

The gas having passed through the secondary mixing section 20A flows to the secondary combustion section 20B at the lowermost part of the furnace, where 99.99999% or more of the waste PCB sent from the main burner 24 is decomposed and burned, and the gas is discharged. It flows out of the outlet 30.

In the second combustion chamber 20, the combustion gas has a residence time of 1 to 2 minutes, and is maintained at 1400 ° C. or higher by the temperature sensor 38B installed above the gas outlet 30.
The controller 40 controls the amount of liquid fuel to be sent to the second mixing burners 28, 28.

As described above, the furnace is divided into upper and lower parts by the center throttle part 16 as a boundary, and during the entire residence time of 2 to 4 minutes, the collision, vortex flow and mixing of the air flow are repeated, and the orifice effect and expansion due to the throttle are repeated. Due to the effect of the reduced water emulsion combustion, a uniform three-dimensional temperature distribution is formed in the furnace.

Further, depending on the type of PCB of the waste PCB (for example, the calorific value differs greatly depending on the number of chlorines bonded to biphenyl) and the degree of mixing of oils, the burners 24, 2
It can respond freely by changing the operating conditions of 6, 28.

The gas flowing out from the gas outlet 30 is subjected to cooling water quench to avoid re-synthesis of dioxin.
The temperature is rapidly lowered to 0 ° C. or less, and the hydrogen chloride content in the exhaust gas is washed by alkali washing, and then discharged to the atmosphere.

As a safety measure, exhaust gas may be extracted downstream by a blower or an ejector so that the operating pressure of the furnace becomes a negative pressure.

[0096]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A 100 kg / h waste PCB having a PCB concentration of 60% and a mixed oil of 40% will be described below.
The flow balance in the furnace in the embodiment where processing is performed at 0, and others will be described.

The waste PCB to be treated is 60% by weight of PCB, 40% by weight of mixed oil, and has a calorific value of 6000 kcal.
/ Kg, PCB is biphenyl tetrachloride, and the mixed oil is heavy oil equivalent (85% C, 15% H).

In this case, since 40% of the heavy oil has a higher burning speed than the PCB, no new liquid fuel is added and the waste P
15% of reduced water based on the total amount of CB is added for the emulsion.

Whether or not liquid fuel is newly added is checked by checking the outputs of the temperature sensors 38A and 38B, and if this output is too low, control is performed so that liquid fuel is added to the mixing burner 24, 26 or 28.

The reason why the burner arrangement in the furnace is dispersed both in the circumferential direction and in the flow axis direction is that, besides the purpose of making the temperature distribution in the furnace uniform, this type of waste PCB can be freely used. The purpose is also to respond.

The size of the furnace in the example of processing 100 kg / h of waste PCB (mixture of 60% of PCB and 40% of oil) (2.4 t / d in continuous operation) is as shown in Table 1 below.

[0102]

[Table 1]

In the actual construction, the construction is performed so that gas does not stay in the narrowed portion and the end plate.

The input / output flow balance at the time of the high temperature incineration of the waste PCB was as shown in Tables 2 and 3 below.

[0105]

[Table 2]

[0106]

[Table 3]

The pressure reducing device 14 for boiling the fuel under reduced pressure is composed of a pressure reducing plate 68 provided with fine holes 68A. However, the present invention is not limited to this. You may.

For example, a pressure reducing device 86 having another structure as shown in FIG. 6 may be used. The pressure reducing device 86 is configured by dividing the intermediate cylinder portion of FIG. 4 into an intermediate portion 55D and both end portions 55E and 55F that are screwed to both sides thereof. In between, the fuel passage 54
And a pair of swirling flow forming blades 88A and 88B for forming swirling flows in opposite directions to the fuel flowing through the swirling flow.

Each of the swirling flow forming blades 88A and 88B has the structure shown in FIG.
As shown in the figure, 8 at equal angular intervals of 45 ° in the circumferential direction.
Of the fuel passage 5
4, when viewed from the axial direction, the phase in the circumferential direction is shifted by 22.5 °.

[0110]

Since the present invention is constructed as described above, P
Dioxins and coplanar P in combustion exhaust gas
It has an excellent effect that it can be decomposed and burned without CB.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a PCB high-temperature incinerator according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control system in the PCB high-temperature incinerator.

FIG. 3 is an enlarged sectional view including a partial block diagram showing a burner according to an embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view showing the main part.

FIG. 5 is a schematic sectional view showing a reduced water producing apparatus.

FIG. 6 is a sectional view showing a second example of the embodiment of the burner.

FIG. 7 is an enlarged side view showing the essential part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... High temperature incinerator 12 ... Fuel supply device 14 ... Pressure reducing device 16 ... Throttle part 18 ... First combustion chamber 18A ... Primary mixing part 18B ... Primary combustion part 19 ... Upper end plate 20 ... Second combustion chamber 20A ... Secondary Mixing section 20B Secondary combustion section 21 Lower head plate 22 Furnace body 22A Peripheral wall 23 Jacket 24 Main burner 26 First mixing burner 28 Second mixing burner 30 Gas outlet 32 Waste PCB tank 34 Fuel tank 35 ... Line mixer 36 ... Reduced water producing device 38A, 38B ... Temperature sensor 40 ... Control device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F23N 1/00 105 F23N 1/00 105C

Claims (12)

[Claims] A liquid fuel containing polychlorinated biphenyl and a liquid hydrocarbon has an oxidation-reduction potential of -100 to 2,500 m
The reduced water reduced to V is mixed in a volume ratio of 5 to 20%,
A method for burning and decomposing polychlorinated biphenyl, which comprises boiling it under reduced pressure to form an emulsion before burning. 2. The method according to claim 1, wherein reduced water and a liquid hydrocarbon whose oxidation-reduction potential has been reduced to -100 to -2500 mV are mixed with the combustion gas of the liquid fuel, and the mixture is emulsified by boiling under reduced pressure. A method for burning and decomposing polychlorinated biphenyl, which comprises spraying and burning while causing turbulent diffusion mixing with a combustion gas. 3. The method according to claim 1, wherein air is blown into the combustion gas of the liquid fuel to cause turbulent diffusion mixing.
A method for burning and decomposing polychlorinated biphenyl, which comprises burning unburned fluid fuel. 4. The method according to claim 1, wherein the sectional area of the discharge flow of the combustion gas of the liquid fuel is reduced to １ ／ or less.
Next, a combustion decomposition method for polychlorinated biphenyl, characterized in that the cross-sectional area of the discharge stream is increased to expand and discharge the combustion gas. 5. The method according to claim 4, wherein reduced water and a liquid hydrocarbon whose oxidation-reduction potential has been lowered to -100 to -2,500 mV are mixed with the expanded combustion gas, and the mixture is boiled under reduced pressure to form an emulsion, followed by spraying. And burning the mixture while causing turbulent diffusion mixing with the expanded combustion gas. 6. The method for decomposing polychlorinated biphenyl according to claim 5, wherein the combustion gas in which the turbulent diffusion mixing has occurred is kept at 1400 ° C. or more for 1 to 2 minutes. 7. The reduced water according to claim 1, wherein first, second, and third electrodes are arranged in the water, and the redox potential is reduced as the first and second electrodes. Using an electrode made of one of aluminum or magnesium to be applied, applying an alternating current between the first and second electrodes,
A grounded electrode, a DC current is passed from the first and second electrodes to the third electrode via the water, and the water is electrolyzed to form a polychlorinated biphenyl. Combustion decomposition method. 8. The method according to claim 1, wherein the liquid hydrocarbon is one of heavy oil, kerosene, light oil, waste oil, alcohol and dimethyl ether. 9. A liquid fuel containing polychlorinated biphenyl and a liquid hydrocarbon has an oxidation-reduction potential of -100 to 2,500 m
A fuel supply device for supplying a mixed fuel obtained by mixing reduced water reduced to V in a volume ratio of 5 to 20%, a pressure reducing device for boiling the supplied mixed fuel under reduced pressure, and a cylindrical shape having both ends covered. A furnace body divided into a first combustion chamber and a second combustion chamber by a constricted portion provided at an intermediate portion in a longitudinal direction, and an upper end plate at an upper end of the first combustion chamber in the furnace body, A first burner that is supplied from the fuel supply device via a decompression device and forms a flame by burning the mixed fuel that is at least partially vaporized by decompression boiling; and a first burner side of the first combustion chamber. Is mounted obliquely toward the upper end plate on the peripheral wall of the first mixing section composed of substantially half the area of the first mixing section, and is supplied from the fuel supply device through the compressed air flow or the decompression device, and is decompressed and boiled. By While the selectively formable at least one first mixing burner flame by combustion of the mixed fuel partially vaporized even without, the second combustion chamber,
On the peripheral wall of the second mixing section composed of a substantially half area on the throttle section side, attached diagonally toward the throttle section, supplied from the fuel supply device via the pressure reducing device, and at least by boiling under reduced pressure It is composed of at least one second mixing burner that forms a flame due to the combustion of the mixed fuel that has been partially vaporized, and the remaining area of the second mixing section of the second combustion chamber, where combustion gas is retained for a certain time. A high-temperature incinerator for polychlorinated biphenyl, comprising: a secondary combustion section; and a gas outlet provided in a lower end plate at a lower end of the second combustion chamber. 10. The method according to claim 9, wherein the flame from the burner and the flame or air flow from the first mixing burner are mixed from the remaining area of the first mixing section of the first combustion chamber to form a turbulent air. A high-temperature incinerator for polychlorinated biphenyl, wherein a primary combustion section for promoting flow diffusion mixing is formed. 11. The gas passage cross-sectional area of the throttling portion according to claim 9 or 10, wherein the gas passage cross-sectional area of the first and second combustion chambers before and after the throttle section is not more than 1/4. High temperature incinerator for polychlorinated biphenyls. 12. The method according to claim 9, wherein the first, second, and third electrodes are disposed in water, and the first and second electrodes are made of a metal that reduces a redox potential. By applying an alternating current between the first and second electrodes and grounding the third electrode, a direct current is supplied from the first and second electrodes to the third electrode via the water. sink,
A high temperature incinerator for polychlorinated biphenyl, further comprising a reduced water producing device for electrolyzing the water and supplying the electrolyzed water to the fuel supply device.