JP2003130324A - Method of processing fluorocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make fluorocarbon harmless by using a powder burner as a burner of an industrial waste incinerator and utilizing the waste incinerator using waste plastic which is industrial waste as a part of fuel. SOLUTION: Fluorocarbon is decomposed at a first temperature by dumping the fluorocarbon with the waste to the burner 10 in which a fuel source is waste plastic. Next, the fluorocarbon is passed in a rotary kiln 20 set to a second temperature which is lower than the range of the first temperature. Next, the fluorocarbon is decomposed in a combustion furnace held at a third temperature which is lower than the first temperature. Next, the fluorocarbon is made harmless by cooling quickly. The first temperature is preferably in a range from 1200 deg.C to 1300 deg.C, the second temperature is in a range from 800 deg.C to 900 deg.C and the third temperature is in a range from 820 deg.C to 870 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorocarbon treatment method, and more particularly to a fluorocarbon treatment method using an industrial waste incinerator.

[0002]

2. Description of the Related Art Conventionally, various methods for detoxifying CFC, which is an ozone depleting substance, have been proposed. For example, known are an ultrahigh temperature hydrolysis method using high frequency thermal plasma, a decomposition method using an industrial waste incinerator, and a supercritical decomposition method using wet decomposition at high temperature and high pressure.

Of these, the detoxification treatment of CFCs using a waste incinerator has been drawing attention in recent years. According to this treatment method, fuel, air and freon are introduced into a rotary kiln of an industrial waste incinerator, and freon is decomposed in a flame formed by the fuel and air. This type of processing method is described in, for example, Japanese Patent Application Laid-Open No. 8-224441, Japanese Patent No. 261034, and Japanese Patent No. 3085358.

[0004]

However, in any of the treatment methods disclosed in the above publications, there is no description of the treatment for detoxifying CFCs in a waste incinerator using a powder burner using waste plastic as a fuel source. There is no description suggesting this.

The present invention uses a powder burner as a burner for an industrial waste incinerator and uses a waste incinerator that uses industrial waste plastic as part of its fuel to detoxify CFCs. The purpose is to provide a method.

[0006]

In order to solve the above problems, the present invention provides a burner using waste plastic as a fuel source,
CFCs are injected together with wastes to destroy the CFCs at a first temperature, and then passed through a rotary kiln set to a second temperature lower than the first temperature range, and then the first temperature. A method for treating CFCs, which comprises destructing CFCs in a combustion furnace maintained at a third temperature lower than the above temperature and then rapidly cooling the CFCs to render them harmless.

Preferably, the first temperature is 1200 °
C to 1300 ° C., and the second temperature is 8
It is in the range of 00 ° C to 900 ° C, and the third temperature is in the range of 820 ° C to 870 ° C.

Further, preferably, the exhaust gas obtained after the rapid cooling is washed with an alkaline washing liquid containing Ca (OH) ₂ and NaOH.

Preferably, the cleaning liquid has a pH of about 4.5.

[0010]

FIG. 1 is a block diagram showing an example of the construction of an industrial waste incinerator used in the present invention.

The illustrated industrial waste incinerator has a powder burner 10 and a rotary kiln 2 which function as a primary combustion furnace.
0, secondary combustion furnace (jet furnace) 30, quenching tower 4
0, cleaning tower (scrubber) 50, cooling liquid tank 60, cleaning liquid tank 62, mist cotrel (electrostatic precipitator) 70, waste water treatment tank 80, flue gas desulfurization tower 90, waste oil tank 100, waste solvent tank 10
2, waste acid liquid tank 104, waste alkali tank 106, neutralization tank 11
0 and filter press 120. The present invention detoxifies chlorofluorocarbon using the industrial waste incinerator having such a configuration.

FIG. 6 is a diagram showing a method for treating freon using the industrial waste incinerator shown in FIG. A powder burner 10 using waste plastic (abbreviated as "waste plastic" in the drawings) as a fuel source burns solid industrial waste. Freon is directly supplied to the powder burner 10 together with the waste plastic. When burning waste plastics, CFCs are destroyed. Further, as described later, air is also supplied to the powder burner 10. This air contains water (water vapor) and oxygen.
Water and oxygen are necessary to prevent the generation of toxic gases when the CFCs are destroyed. The temperature (first temperature) of the powder burner 10 is, for example, 1200 ° C to 1300 °.
It is C. This temperature range is extremely higher than about 800 ° C., which is a non-catalytic CFC decomposition temperature. Also,
The residence time in the powder burner 10 is, for example, 1 second. The CFC decomposition rate at the outlet of the powder burner 10 is 70%.
~ 90%.

The structure and operation of the powder burner 10 will be described later in detail.

The rotary kiln 20 burns the waste processed by the powder burner 10 at a predetermined temperature (second temperature) for a predetermined residence time while stirring (step S11 in FIG. 6). The predetermined residence time is, for example, 20 seconds.
Further, the predetermined temperature is within a range of 800 ° C to 900 ° C. Due to the combustion treatment of the waste in the rotary kiln 20, the CFC decomposition reaction proceeds.

By the combustion process in the rotary kiln 20,
Exhaust gas and cinder are discharged. The fuel shell serves as a raw material for cement as shown in FIG. The exhaust gas is supplied to the secondary combustion furnace 30. The CFC decomposition rate at the outlet of the rotary kiln 20 is 90 to 99%.

The secondary combustion furnace 30 heats the exhaust gas at a predetermined temperature (third temperature) for a predetermined residence time to completely burn the waste (step S12). The predetermined temperature is, for example, within a temperature range of 820 ° C to 870 ° C. The predetermined residence time is, for example, 2 seconds. By this process,
It is possible to completely burn combustible substances such as dioxins, unburned carbon, CO, and organic malodorous substances. The CFC decomposition rate at the outlet of the secondary combustion furnace 30 is 100%.

For example, the decomposition reaction formula of Freon-11 (CFC-11) is as follows.

CCl ₃ F + 2H ₂ O → CO ₂ + 3HCl + HF Further, the decomposition reaction formula of Freon-12 (CFC-12) is as follows.

CCl ₂ F ₂ + 2H ₂ O → CO ₂ + 2HCl + 2HF Other Freon CFC113, CFC-114, CFC
-115, HCFC-22, etc. are similarly decomposed.

The above CFC decomposition reaction is caused by the powder burner 10,
It is performed in the rotary kiln 20 and the secondary combustion furnace 30.

The gas discharged from the secondary combustion furnace 30 is 50 ° in the quenching tower 40 using the cooling water from the cooling liquid tank 60.
It is rapidly cooled to a temperature of C to 90 ° C (step S1).
3). In addition, "P" shown in FIG. 1 means a pump. The cooling water circulates through the cooling tower 40 and the cooling liquid tank 60, and is discharged into the wastewater treatment tank 80. By rapidly cooling the exhaust gas, generation and resynthesis of dioxins can be effectively suppressed.

The exhaust gas which has been subjected to the quenching treatment in the quenching tower 40 is washed in the washing tower 50 (neutralization / insolubilization treatment) (step S14). The cleaning liquid is sprayed in the form of fine droplet particles, and the exhaust gas comes into contact with the cleaning liquid to be cleaned. The cleaning liquid circulates in the cleaning tower 50 and the cleaning liquid tank 62, and is discharged to the waste water treatment tank 80. The washed exhaust gas is subjected to dust removal processing by the mist cotrel 70 (step S1
5) It is released from the flue gas desulfurization tower 90 to the atmosphere (“exhaust collision” in step S16).

The cleaning liquid is preferably alkaline water. The pH is preferably around 4.5. Further, it is preferable that calcium oxide Ca (OH) ₂ and sodium hydroxide NaOH are added to the cleaning liquid. Ca (O
H) ₂ reacts with HCl and HF obtained by decomposing Freon to give calcium fluoride CaF and sodium fluoride NaF.
Becomes Further, NaOH reacts with HCl and HF to form sodium chloride NaCl and calcium chloride CaCl. By using NaOH, the occurrence of scale trouble can be effectively prevented.

The cleaning liquid discharged to the waste water treatment tank 80 is taken as a cement raw material through the steps shown in FIG. 6, and the final filtrate is discharged.

FIG. 2 is a view showing the powder burner 10 and its surroundings, and FIG. 4 is a vertical sectional view of the powder burner 10.

The powder burner 10 is a burner which uses coated nugget scraps as auxiliary fuel. A coated nugget is a residue (a coating material) obtained by finely cutting a waste copper wire or an aluminum wire, which is a type of industrial waste that is generated in large quantities at civil engineering and construction sites, and removing metal components, and polypropylene (PP) or polyethylene. (PE), vinyl chloride (PVC), coated fiber (paper), and metal (copper or aluminum). As wastes containing such synthetic resin as a main component, other waste plastics such as polyethylene container (PE), chemical drum (made of PE), automobile bumper (made of PP), and OA equipment plastic (made of ABS) are crushed. There is something I did.

The powder burner 10 has a cylindrical combustion chamber 12 which is vertically erected inside the powder burner 10, and an oil burner 14, coated nugget wastes and the like and a primary air injection port 16 are arranged on the peripheral wall in order from the top. The secondary air injection ports 18 are provided so that the respective injection products are introduced tangentially into the combustion chamber 12. The introduction of CFCs is performed via a roots blower 16a described later. Further, a tertiary air injection port 19 is provided in the combustion chamber 12 so as to be introduced in the axial direction of the blow nozzle 22.

The roots blower 16a is a primary air injection port 1
It connects to the middle of the line connecting to 6. As shown in FIG. 3, Freon is supplied from two Freon gas supply devices. Each system is provided with a flon cylinder 31, a plastic case 32 containing hot water 33, a hose 34 connecting the flon cylinder 31 and the valve 35, and a supply pipe 36 connecting to a line connecting the valve 35 and the roots blower 16a. The plastic case 32 is provided with a ribbon-shaped heater (not shown) that controls the temperature of the hot water 33. The warm water 33 is kept below 40 ° C.
As a result, the fluorocarbon in the fluorocarbon cylinder 31 is evaporated.
The evaporated chlorofluorocarbon gas is supplied into the combustion chamber 12 of the powder burner 10 via the hose 34, the valve 35, the supply pipe 36 and the roots blower 16a.

The chlorofluorocarbon thus supplied is mixed with an amount of water vapor necessary for decomposing (destructing) the chlorofluorocarbon, and the chlorofluorocarbon is destroyed together with the waste at a temperature of 1200 ° C to 1300 ° C.

The oil burner 14 is an oil pump 14a.
Recycled fuel oil and combustion air blower 14
The air sent from b is injected into the combustion chamber 12 to heat the inside of the furnace. The oil burner 14 is used for preheating in the combustion chamber 12, and the internal temperature is 400 to 500 °.
When the temperature reaches C, extinguish the oil burner 14. After that, combustion is continued simply by blowing the coated nugget scraps into the combustion chamber 12. As a result, it is possible to further reduce the running cost of recycled heavy fuel oil.

Coated nugget waste and primary air jet 16
Is introduced into the combustion chamber 12 in a state where the coated nugget scraps used as fuel and the primary air are mixed. The coated nugget scraps and the like are cut into about 1 to 8 mm and stored in the raw material hopper 15a, and the screw conveyor 15b is arranged below the raw material hopper 15a. Then, the disc feeder 1 for gradually sending out the coated nugget scraps and the like sent by the screw conveyor 15b.
5c is provided. The screw conveyor 15b
A buffer may be provided between the disk feeder 15c and the disk feeder 15c so that the feeding amount can be kept constant.

The coated nugget scraps and the like supplied from the disc feeder 15c are roots blower 1 for supplying primary air.
The primary air sent from 6a is jetted into the combustion chamber 12 from the coated nugget dust and the primary air jet port 16. In the present embodiment, the blower for secondary / tertiary air is also branched to the secondary air injection port 18 and the tertiary air injection port 19 by using the roots blower 16a to branch the pipe.
Air is supplied while adjusting the optimum pressure. Of course, a blower can be provided for each of the secondary and tertiary air.

The blowing nozzle 22 is provided so as to connect the bottom portion 12a of the powder burner 10 to the side surface portion of the main body of the rotary kiln 20 on one side thereof. Reference numeral 22a indicates the bottom surface of the combustion chamber 12, and 22b indicates the side surface. The coated nugget scraps and the like burn in the combustion chamber 12, and the generated flame is discharged from the bottom portion 12a of the combustion chamber 12 and introduced into the rotary kiln 20 through the blow nozzle 22.

Generally, the residence time of the coated nugget debris in the combustion chamber 12 changes depending on the velocity of the coated nugget debris and the primary air when they are introduced into the combustion chamber 12. When the velocity of the coated nugget wastes and the primary air is high, the coated nugget wastes and the primary air and CFCs spirally move along the inner peripheral surface of the combustion chamber 12 for a long time, so that the residence time also becomes long. Further, since the coated nugget scraps and the like are in a high temperature state near the outlet of the combustion chamber of the powder burner and are easily burned, secondary air is ejected from the secondary air injection port 18 provided near the middle portion of the combustion chamber 12. Introduce or the combustion chamber 1
It is possible to adjust so as to perform complete combustion by introducing the tertiary air from the tertiary air injection port 19 provided near the bottom of No. 2. Furthermore, the shape of the flame introduced into the main body of the rotary kiln 20 by the injection of the tertiary air can be optimized. In general, the flame introduced into the rotary kiln 20 preferably has a shape that can be applied to a wide range so that the industrial waste supplied to the rotary kiln 20 can be burnt, specifically, in the horizontal direction. It has a long shape.

FIG. 5 is a process chart showing the treatment of the powder burner 10. First, as a preparatory step, the coated nugget scraps and the like cut into about 1 to 8 mm are stored in the raw material hopper 15a, and the disc feeder 1 is driven by the screw conveyor 15b.
5c can be supplied. As described above, the coated nugget and the like are residues (coated nugget scraps) obtained by finely cutting waste copper wire or aluminum wire, which is a type of industrial waste that is generated in large quantities at civil engineering construction sites, etc. And wastes made of synthetic resins such as polyethylene containers, chemical drums (made of PE), automobile bumpers (made of PP), and plastics for OA equipment (made of ABS).

The main component of the coated nugget waste is plastic (waste plastic) made of synthetic resin such as polypropylene or polyethylene. Since polypropylene and polyethylene have specific gravities of 0.9 and 0.94, respectively, the specific gravity is 1. When placed in water, it can be separated from copper wire or aluminum wire by specific gravity separation. When copper nugget scraps of appropriate length are put in a water tank and stirred, PP, PE, etc. are peeled off from the metal components and float on the water surface. Coated fibers (paper) and vinyl chloride are deposited on the bottom of the aquarium together with the metal. At this stage, the vinyl chloride that causes hydrogen chloride is
It can be separated from PE.

Then, together with the combustion air supplied from the combustion air blower 14b, the regenerated heavy oil as fuel is sent from the oil pump 14a to the oil burner 14 provided near the top of the powder burner and burned in the combustion chamber 12. (Step S1). Next, the coated nugget scraps and the like that can be supplied as auxiliary fuel are mixed with the air and freon sent from the roots blower 16a and the coated nugget scraps and the primary air injection port 1
The fuel is injected tangentially into the interior of the combustion chamber 12 from 6 and introduced into the combustion chamber 12, and is burned while swirling inside the combustion chamber 12 (step 2).

Then, a part of the air sent from the roots blower 16a is introduced from the secondary air injection port 18 into the combustion chamber 12 of the powder burner 10 from its tangential direction (step S).
3) Furthermore, a part of the air sent from the roots blower 16a is supplied from the tertiary air injection port 19 to the combustion chamber 1 of the powder burner 10.
2 (step S4). Then, the flame generated in the powder burner 10 is introduced from the bottom side of the combustion chamber 12 into the rotary kiln 20 through the connected blow nozzle 22 and is supplied into the primary combustion chamber 4. The waste is incinerated and the chlorofluorocarbon is destroyed (step S5).

[0039]

[Embodiment] Next, an embodiment of a CFC processing method using the above waste incinerator will be described. The following examples include tests of CFC detoxification treatment and the test results. (1) The incinerator powder burner 10 has a diameter of 600 mm and a length of 1,300.
mm. Rotary kiln is 50,000m long
m, 4,200 mm for large diameter parts and 3, 200 mm for thin parts
It is 600 mm. The secondary combustion furnace 30 has a diameter of 4,500.
mm and the length is 8,550 mm. The in-furnace volume, operating temperature and residence time are shown in Table 1.

[0040]

[Table 1] (2) Freon used R-12 (1) 3 cylinders (37.9 kg) R-12 (2) 1 cylinder (15.6 kg) R-22 2 cylinders (43.0 kg) R-12 (Part 3) Nine cylinders (135.1 kg) (3) The temperature was adjusted to about 20 ° C. with a freon temperature control heater. (4) Freon addition rate The destruction rate of about 30 kg / h was adjusted so that the total 15 flon cylinders described above could be destroyed in 4 hours x 2 days.
The total throughput including waste per day is about 3.7 tons / hour. (5) The operating temperatures (° C) of each part on the first day and the second day are as shown in Tables 2 and 3, respectively. The cooling temperature in the quenching furnace 40 was set in the range of 50 ° C to 90 ° C. Furthermore, the pH of the cleaning liquid of the quenching tower 50 is 4.5, and Ca (O
H) ₂ and alkaline water containing NaOH was used.

[0041]

[Table 2]

[0042]

[Table 3] (6) CFC input amount CFC input is 30 using a flow meter (not shown) as a guide.
The weight of the cylinder was measured before and after the destruction treatment so that the cylinder weight became kg / h. Table 4 shows the average input amount of CFCs.

[0043]

[Table 4] (7) The measurement results on the first day and the second day are shown in Tables 5 and 6.

[0044]

[Table 5]

[Table 6] As shown in Tables 5 and 6, the CFC content during and after the CFC injection was less than 0.1 ppb as before CFC injection, and it can be seen that the CFC treatment method described above can render CFCs harmless. In addition, chlorine compounds, fluorine compounds, and other air pollutants are well below the emission standards of the Air Pollution Control Law, and there is no effect of CFC destruction. In particular, for the fluorine drainage,
It is smaller than the values before and after the introduction of CFCs.

In the above-mentioned embodiment, the operating temperature of the powder burner 10, that is, the combustion temperature of waste and chlorofluorocarbon is 1200 ° C.
However, similar actions and effects can be obtained within the range of 1200 ° C to 1300 ° C. Further, in the above-mentioned embodiment, the operating temperature of the rotary kiln 20, that is, the combustion temperature is 800 ° C, but the same action and effect can be obtained within the range of 800 ° C to 900 ° C. Further, in the above embodiment, the operating temperature of the secondary combustion furnace 30, that is, the combustion temperature is 8
Although it was 50 ° C, the same action and effect can be obtained at a temperature of 820 ° C to 870 ° C.

[0046]

As described above, according to the present invention,
A powder burner can be used as a burner of an industrial waste incinerator, and a waste incinerator that uses industrial waste plastic waste as part of its fuel can be used to detoxify CFCs.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a waste incinerator used in an embodiment of the present invention.

FIG. 2 is a diagram showing a powder burner of the waste incinerator shown in FIG. 1 and its surroundings.

FIG. 3 is a diagram showing a configuration example of a CFC gas supply device.

FIG. 4 is a vertical sectional view of the powder burner shown in FIG.

FIG. 5 is a process chart showing the treatment of the powder burner.

FIG. 6 is a process diagram showing the processing of industrial waste including CFC destruction.

[Explanation of symbols]

10 powder burner 20 rotary kiln 30 Secondary combustion furnace 31 Fron cylinder 32 plastic cases 33 hot water 34 Hose 35 valves 36 Supply piping 40 quenching tower 50 washing tower 60 Coolant tank 62 cleaning liquid tank 70 Mist Cottrell 80 wastewater treatment tank 90 Flue gas desulfurization tower

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C07C 19/10 F23G 5/20 A F23G 5/20 7/12 Z 7/12 F23J 15/00 E F23J 15 / 04 K 15/06 B01D 53/34 134C F term (reference) 3K061 AA07 AA16 AB01 AC01 AC13 BA05 CA02 FA05 FA21 FA28 KA02 KA15 3K070 DA05 DA16 DA37 DA38 3K078 AA05 BA03 BA13 BA26 CA02 CA08 CA12 CA18 4D002 A22 BA05 BA21 A21 A05 BA21 A21 BA05 A21 BA14 CA01 CA13 DA02 DA05 DA12 DA35 DA66 DA70 EA02 FA02 FA04 GA01 GB03 GB09 HA01 HA02 4H006 AA05 AC13 AC26 AD18 BC10 BC16 EA02

Claims (4)

[Claims] 1. A burner using waste plastic as a fuel source is charged with CFCs together with wastes to destroy CFCs at a first temperature, and then set to a second temperature lower than the first temperature range. After passing through the rotary kiln,
A method for treating CFCs, which comprises destructing CFCs in a combustion furnace maintained at a third temperature lower than the first temperature and then rapidly cooling the CFCs to render them harmless. 2. The first temperature is 1200 ° C. to 130 ° C.
Is within the range of 0 ° C, and the second temperature is from 800 ° C to
In the range of 900 ° C, and the third temperature is 820 °
The CFC processing method according to claim 1, wherein the CFC temperature is in the range of C to 870 ° C. 3. The exhaust gas obtained after quenching is changed to Ca (O 2
The method for treating CFCs according to claim 1 or 2, wherein the method is performed by cleaning with an alkaline cleaning solution containing H) ₂ and NaOH. 4. The method for treating CFCs according to claim 3, wherein the cleaning liquid has a pH of about 4.5.