JPH10151321A - Method for thermally decomposing cfc or the like and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely decomposed a CFC or the like even in the case of keeping a high temp. only for a short time by using a compression section of a displacement type compressor as a decomposition section, feeding the CFC or the like and an auxiliary material in the decomposition section and adiabatically compressing the CFC or the like to increase the temp. once to the decomposition temp. to cause the exothermic reaction of the CFC by the adiabatic compression. SOLUTION: In the operation of a decomposing device 10, an air stop valve 32a is opened at first, warming-up and oiling are started by driving a driving means 17 and after that, the air stop valve 32a is closed, the recovered CFC and the auxiliary material are fed to the compression section 12 with a CFC stop valve 18a and an auxiliary material stop valve 19b opened. And the CFC and the auxiliary material are mixed with each other in the ascending process of a piston 11b and simultaneously the temp. is increased by the adiabatic compression. As a result, the decomposition reaction of the CFC and the synthetic reaction with the auxiliary material are performed. When the piston 11b shifts to the descending process, the gas in the compression section 12 is adiabatically expanded to decrease the temp. to the normal temp. and discharged to an exhaust passage 13. The decomposition gas in the waste gas is neutralized the contact with a neutralizing material at the time of passing through a neutralizing case 13a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for thermally decomposing harmful substances containing chlorides (hereinafter referred to simply as chlorofluorocarbon) such as chlorofluorocarbon refrigerant, halon fire extinguishing material, or iperito gas which is a kind of chemical weapon. It is about.

[0002]

2. Description of the Related Art Freon and the like directly and indirectly harm the human body, so that Freon recovered after use (hereinafter referred to as "recovered Freon") must be decomposed prior to disposal. However, since fluorocarbons and the like are chemically stable and difficult to decompose, a thermal decomposition method of decomposing by heating to a high temperature has been proposed. In the thermal decomposition method, chlorofluorocarbon or the like is heated to 800 ° C. or higher to decompose it, and a part of the gas (hereinafter referred to as a “decomposed gas”) reacts with an auxiliary material to prevent reversible reaction. Specifically, there are the incinerator method using a waste incinerator and the submerged combustion method using a gas burner.At the experimental stage, the kiln method in which a kiln for sintering cement is diverted, and high heat and high temperatures such as plasma and explosives are used. Methods such as decomposition by energy have been tried.

[0003]

However, the conventional apparatus has a large external shape, is poor in portability, and is expensive and poor in practical use. The causes of the increase in the size of the device are as follows. Fuel for raising the temperature of CFCs to the decomposition temperature was required, and a large amount of combustion gas was generated, and the decomposition chamber, cooling chamber, or ducts became large. 2. It took a long time for heat exchange for flon and the like to obtain heat from the combustion gas and cause a decomposition reaction. As a result, the following problems have occurred. 1. The preparation time and cooling period from the start of the operation of the apparatus to the start of the decomposition operation or from the stop of the decomposition operation to the stop of the apparatus required a long time, and the operation time efficiency was low. 2. Decomposition gas containing hydrogen chloride as a main component was diluted in a large amount of combustion gas and was difficult to recover. 3. Since it takes a long time for the decomposition gas and the combustion gas to cool, the amount of dioxin generated in the process has increased.

[0004]

Means for Solving the Problems The above-mentioned problem is solved as a method. The compression chamber of a positive displacement compressor is used as a decomposition chamber, and chlorofluorocarbon and other auxiliary materials are fed into the decomposition chamber, and the fluorocarbon and other materials are adiabatically compressed inside the decomposition chamber to raise the temperature to the decomposition temperature once. 2. The decomposition chamber is constituted at least in two stages before and after a first decomposition chamber and a second decomposition chamber connected in series, and CFCs and the like heated to the decomposition temperature in the first decomposition chamber are decomposed again in the second decomposition chamber. Raise temperature to temperature. 3. The working volume of the former decomposition chamber is set to be larger than the working volume of the latter decomposition chamber. 4. The first-stage decomposition chamber is composed of a plurality, and at least the number of the first-stage decomposition chambers is set to be larger than the number of the second-stage decomposition chambers. It is characterized by the following. The combustion chamber of the internal combustion engine arranged in the front stage and the decomposition chamber constituted by the compression chamber of the positive displacement compressor arranged in the rear stage are connected in series, and Freon etc. are fed into the intake passage of the internal combustion engine together with fuel. Adiabatic compression of decomposed gas such as chlorofluorocarbon discharged together with exhaust gas from the exhaust passage of the internal combustion engine to the decomposition temperature of chlorofluorocarbon and the like again in the decomposition chamber. 2. A cylinder block having a plurality of compression chambers each having a piston and a cylinder is provided, a part of which is a combustion chamber of an internal combustion engine, and the remaining compression chambers are decomposition chambers such as Freon. The problem is solved by such means.

[0005]

[Action]

Action of claim 1: Fluorocarbons and the like are fed into a decomposition chamber composed of a compression chamber, and are adiabatically compressed to a high temperature exceeding 800 ° C. in the compression process, thermally decomposed, react with auxiliary materials, and react with hydrogen chloride and fluoride. Changes to decomposition gas such as hydrogen. In the expansion process, the gas is adiabatically expanded, rapidly cooled to a temperature lower than room temperature, and discharged to the outside. Since the decomposition is performed by its own heat generation such as chlorofluorocarbon in the compression process, the decomposition reaction is performed in a short time without requiring heat transfer time as in the case of being heated by another medium such as combustion gas, and the auxiliary material is used. Is completed, and a decomposed gas that does not react reversibly is obtained. The use of water as an auxiliary material is effective only for the reaction under high pressure as in the present invention. When LPG such as propane or butane is used as an auxiliary material, if the temperature in the compression chamber exceeds 1400 ° C., it is thermally decomposed and partly becomes methane, and methane itself acts as an auxiliary material. Operation of claim 2... Each time the chlorofluorocarbon and the like pass through the compression chambers (decomposition chambers) provided in multiple stages, the temperature rises to the decomposition temperature or higher and the reaction time is accumulated. Actions of the third and fourth aspects: Freon and the like are discharged after being heated by the compression chamber provided in the preceding stage. Since a further increased amount of gas is fed into the subsequent compression chamber, the adiabatic compression in the latter compression chamber raises the temperature of Freon and the like to higher heat. Action of claim 5: CFCs are heated to a higher temperature by the combustion gas in the combustion chamber of the internal combustion engine and decomposed in a short time to become a decomposition gas. In addition, since the former positive displacement compressor is an internal combustion engine, the latter positive displacement compressor can be driven by its shaft output. Operation of claim 6: The combustion chamber that generates power and the compression chamber that exclusively consumes power are integrated, and the portability of the pyrolysis apparatus is increased.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a first embodiment showing a pyrolysis apparatus 10 such as a chlorofluorocarbon. The decomposition device 10 has a positive displacement compressor 11 as a main part. The positive displacement compressor 11 is classified as a flow type compressor (not shown), and is characterized by having a compression chamber 12. In this embodiment, the positive displacement compressor 11 is a reciprocating type having a cylinder block 11a and a piston 11b. More specifically, the main body of a commercially available 1300 cc four-stroke diesel engine for passenger cars is used as it is, and three compressors are used. The chambers 12 are arranged side by side. Note that it is not essential that the base be a diesel engine, and that the compression ratio is somewhat low. The part to be diverted is the cylinder block 11a including the cylinder head of the engine, and the intake pipe and the exhaust pipe are excluded. And
After diversion, the intake passage 3 unique to pyrolysis equipment such as chlorofluorocarbon
2, an exhaust passage 13 or a connection pipe 14 is added.
Reference numeral 15 denotes a drive shaft for driving the piston 11b, and the crankshaft of the base engine is used as it is.

A pulley is provided at the end of the drive shaft 15,
The drive shaft 15 is driven by an electric motor via a toothed transmission belt 16,
1000 driven by driving means 17 such as an internal combustion engine.
Rotate at rpm. The driving means 17 is 3.3K in this figure.
w AC motor. The intake passage 32 is formed of a tournament-type branch pipe, and the open end thereof is communicated with the atmosphere and closed by an air opening / closing valve 32a composed of a normally-closed butterfly valve. A cylinder 1 containing a used collected Freon via an evaporator (not shown) is provided at the junction of the branch pipe.
The recovery flon passage 18a communicating with the auxiliary material passage 8 is connected to an auxiliary material passage 19a communicating with a container 19 for a decomposition aid such as LPG or water. Reference numerals 18b and 19b denote a CFC open / close valve and an auxiliary material open / close valve provided in the recovery Freon passage 18a and the auxiliary material passage 19a, respectively. The auxiliary material is used to prevent thermally decomposed chlorofluorocarbons from being recombined during the cooling process. Generally, methane or other methane-based hydrocarbons or water is used. The function of the auxiliary hydrocarbons and water is understood from the following chemical formula. CF ₂ Cl ₂ + CH ₄ + 2O ₂ → 2HCl + 2HF +
2CO ₂ CF ₂ Cl ₂ + 2H ₂ O → 2HCl + 2HF +
CO ₂ As is clear from the above equation, but to act as an auxiliary material is methane (CH _4), butane, methane decomposes by heat at the time of decomposing the methane series hydrocarbons chlorofluorocarbon such as propane When adding as an auxiliary material, it is not necessary to limit to methane, and commercially available propane or butane is sufficient. The exhaust passage 13 is formed of a tournament-type collecting pipe, and a neutralizing case 13a is interposed in the collecting section, and the rear end is opened to the atmosphere. Apparatus (not shown) is added. The neutralizing case 13a is connected to the neutralizing material container 13c through the hollow material passage 13b, and a neutralizing material such as caustic soda or slaked lime is injected. 13d is a neutralizing material on-off valve.

Next, the operation of the first embodiment will be described. First, the air opening / closing valve 32a is opened to start the electric motor serving as the driving means 17 with a light load, thereby performing warm-up and refueling. When the warm-up operation for several minutes is completed, the air on-off valve 32a is closed and the Freon on-off valve 18b and the auxiliary material on-off valve 19b are opened, and the collected Freon and auxiliary material are sent to the three compression chambers 12 arranged side by side. Is done. In the upward stroke of the piston 11b, the chlorofluorocarbon and the like fed into the compression chamber 12 cause a violent turbulent flow to be homogeneously mixed with the auxiliary material, and are simultaneously adiabatically compressed to a compression ratio of about 18 to 20 and instantaneously up to a high temperature exceeding 800 ° C. Raise the temperature. Since this temperature rise is simultaneously generated in the compression chamber 12 except for a portion that is very close to the wall surface of the piston or the cylinder hole and easily radiates heat, the decomposition reaction of the recovered CFC and the synthesis reaction by the auxiliary material are instantaneously performed and completed. When the piston 11b starts to move downward, the gas in the compression chamber 12 adiabatically expands, rapidly drops to near normal temperature, and is discharged into the exhaust passage 13. When the decomposition gas in the exhaust gas passes through the inside of the neutralization case 13a,
A is neutralized by contact with slaked lime or a neutralizing material such as a 15% aqueous solution of caustic soda, and is removed by a known filter (not shown). Thus, the sent Freon is kept at a temperature of 800 ° C. or more for at least 0.025 seconds, during which the decomposition reaction of the collected Freon is completed.

FIG. 2 shows a second embodiment of the thermal decomposition apparatus 10. Here, the main body of the positive displacement compressor 11 uses the same cylinder block 11a as in the previous example, but the configuration of the piping is changed, and two of the three compression chambers 12 are connected in parallel to form a front stage F, and the remaining stages remain. It is knitted in a two-stage configuration in which one is a rear stage R. In the same manner as described above, a cylinder 18 and the like accommodating the collected Freon are connected to the gathering portion of the intake passages 12 of the two positive displacement compressors 11 forming the front stage F. Further, the exhaust gas of the former stage F is collected and connected to the remaining one intake passage 12b forming the latter stage R via the connection pipe 14, so that the latter stage R
The exhaust passage 21 connected to the neutralizing case 1
3a. According to this embodiment, as in the first embodiment, in the pyrolysis apparatus 10, chlorofluorocarbon and the like are fed into the compression chamber 12 in the former stage F, and the chlorofluorocarbon and the like generate heat by themselves in the compression stroke to thermally decompose and connect. It is discharged into the pipe 14. In the discharge pipe 14, the decomposition gases discharged from the two compression chambers 12, 12 are collected and pressurized to form one compression chamber 1 forming the subsequent stage R.
It is led to 2. The fed gas is again adiabatically compressed and becomes high heat, and the reaction time is accumulated. Therefore, if undecomposed components are present, the decomposition proceeds further. Incidentally, the means for pressurizing the gas to be sent to the subsequent stage R can set the compression ratio of each compression chamber 12 low. And it can also be changed by making the volume of the compression chamber 12 of the front stage F larger than that of the rear stage R.

FIGS. 3 and 4 show a third embodiment of the thermal decomposition apparatus 10. FIG. The third embodiment is an example in which the former stage F and the latter stage R are formed separately. Here, the positive displacement compressor 11 is
The rear stage R has a stroke capacity of 2000cc each of four cylinders and is constituted by an engine driven by gasoline or LPG. As shown in FIG. 6, the front stage F and the rear stage R are driven synchronously with a phase difference of about 270 ° via a toothed transmission belt 13. In FIG. 6, the positions of the piston 11b in the combustion chamber 12a and the compression chamber 12 are shown above and below the table. An existing fuel system 2 such as a carburetor and a fuel injection device attached to the engine
3 is provided, and a passage 24 for the collected Freon and auxiliary material is provided. Reference numeral 22a denotes an existing throttle valve for adjusting the engine output. The four exhaust passages e connected to the four compression chambers 12 in the front stage F are connected to the intake passage i in the rear stage R by four connection pipes 14, 14. Note that portions denoted by the same reference numerals as those in the first and second embodiments have the same functions, and will be replaced by the above description.

When the engine forming the front stage F is started, about 10
Operated at 00 rpm. In the compressor of the front stage F in which Freon and the like are fed, in the latter stage of the compression stroke and the combustion stroke, 0.03 to 0.03
The inside of the compression chamber 12 (combustion chamber 12a) is maintained at a high temperature of 800 ° C. or more for a relatively long time of 0.04 seconds. When the engine is ignited by a spark plug (not shown) and enters an expansion stroke, combustion gas and decomposition gas mix at the end thereof and are discharged from the exhaust passage e, and they are in a suction stroke through the connection pipe 14. It is guided to the compression chamber 12 of the latter compressor R. The opening and closing timings of the intake valve IN and the exhaust valve EX of a commercially available engine are set for the purpose of generating a high output, and the exhaust valve EX opens relatively quickly. It is preferable to experimentally correct the opening / closing timing of the valve EX. The combustion gas and the decomposed gas sent to the latter compressor R are adiabatically compressed in the compression stroke, and the temperature rises again to a high temperature exceeding 800 ° C.

FIG. 5 shows a fourth embodiment of the thermal decomposition apparatus 10. The fourth embodiment is an example in which two cylinders of a three-cylinder engine are used as a front-stage F combustion chamber 12a and the remaining one cylinder is used as a rear-stage R adiabatic compression type compression chamber 12. The intake passage 22 connected to the front stage F is the third intake passage shown in FIG.
The point that the exhaust path of the former stage F is connected to the latter stage R by the connecting pipe 14 and the configuration of the exhaust passage 13 that is connected to the latter stage R are substantially the same as those of the second embodiment shown in FIG. Their explanation is as described above. Therefore, the process of disassembling CFCs and the like is substantially the same as that of FIG. 3, but is compact in that it can be assembled into one engine without using a plurality of cylinder blocks 11a as shown in FIG. It can be manufactured at low cost because it uses the engine as a piston crank mechanism, which is expensive and can be used at high cost.

[0013]

According to the first aspect, chlorofluorocarbon and the like fed into the thermal decomposition apparatus 10 are adiabatically compressed in the compression chamber 12 and generate heat themselves to be decomposed. Therefore, 1. CFCs and the like generate heat by adiabatic compression, so that heat exchange time is not required as in the case of receiving heat from combustion gas, and reliable decomposition can be obtained even when the temperature is kept high for a short time. 2. Since the decomposition reaction is completed in a short time, a large amount of fuel is not required as a heat source, which is economical. 3. Due to the small amount of gas emitted, a. The equipment is small, easy to manufacture and excellent in portability. b. Since the gas amount is small, it is easy to remove hydrochloric acid and hydrofluoric acid from the decomposition gas. 4. Since the disassembly operation of the chlorofluorocarbon and the like is started almost simultaneously with the operation of the positive displacement compressor, the preparation period at the start and end times of the disassembly operation is short, and the operation time efficiency is excellent. 5. Since the cracked gas is rapidly cooled by the adiabatic expansion in the expansion process, the hydrochloric acid in the cracked gas does not generate harmful substances in the cooling process. According to the second, third, and fourth aspects, CFCs and the like are decomposed into two stages by the front stage F and the rear stage R, so that the decomposition time is accumulated and becomes long. Therefore, 1. By diverting an existing engine, a pyrolysis apparatus having a large amount of decomposition capacity can be formed in a small size. 2. Further, since the capacity of the compression chamber of the former stage F is larger than that of the latter stage R, the gas is pre-pressurized and sent to the compression chamber of the latter stage R, and the time for maintaining the reaction temperature can be prolonged. According to claim 5, 1. By using an internal combustion engine for the device, a biston crank mechanism having a complicated structure can be obtained at low cost. 2. The decomposition gas discharged from the front stage F is diluted with the combustion gas to increase the amount thereof, and the gas sent to the compression chamber of the rear stage R is pre-pressed, so that higher decomposition efficiency can be obtained. 3. Since the output of the engine forming the front stage F can drive the compression chamber (compressor) of the rear stage R and does not require external power such as an electric motor, the structure is reduced in size and the portability is increased. 4. When the exhaust gas temperature in the first stage is high, the exhaust gas temperature can be lowered by mechanical loss in the second stage R. According to the sixth aspect, since a part of the cylinders of the multi-cylinder engine is used for power and the remaining part is used as a disassembly chamber, a pyrolysis apparatus can be obtained without specially manufacturing a complicated piston crank mechanism. And so on.

[Brief description of the drawings]

FIG. 1 is a plan view of a first embodiment showing a system of a thermal decomposition apparatus.

FIG. 2 is a plan view corresponding to FIG. 1 showing a second embodiment of the thermal decomposition apparatus.

FIG. 3 is a plan view corresponding to FIG. 1 showing a third embodiment of the thermal decomposition apparatus.

FIG. 4 is a plan view corresponding to FIG. 1 showing a fourth embodiment of the thermal decomposition apparatus.

FIG. 5 is a side view thereof.

FIG. 6 is an operation timing chart showing operation timing.

[Explanation of symbols]

10 ··· pyrolysis device 11 ··· positive displacement compressor 11a ··· cylinder block 11b ··· piston 12 ··· compression chamber 12a ··· combustion chamber 13 ··· exhaust passage 13a ··· · Neutralizing case 13b · · · Hollow material passage 13c · · · Neutralizing material container 13d · · · Neutralizing material on / off valve 14 ··· Connection pipe 15 ··· Drive shaft 16 ··· Transmission belt 17 .... Drive means (electric motors, internal combustion engines) 18
· · · Cylinder 18a · · · collection Freon passage 18b · · · Freon on-off valve 19 · · · container for auxiliary decomposition material 19a · · · auxiliary material passage 19b · · · auxiliary material on-off valve 22, 32 · · · intake passage 22a: throttle valve for output adjustment 23: fuel system 24: passage for recovered Freon and auxiliary materials 32a:
・ Air opening / closing valve F ・ ・ ・ ・ ・ ・ Front stage (Positive displacement compressor) R ・ ・ ・ ・ Rear stage (Positive displacement compressor) e ・ ・ ・ Exhaust path i ・ ・ ・ Intake path

Claims (6)

[Claims] A compression chamber of a positive displacement compressor is used as a decomposition chamber, and chlorofluorocarbon and other auxiliary materials are fed into the decomposition chamber, and the fluorocarbon and the like are adiabatically compressed inside the decomposition chamber to temporarily raise the temperature to the decomposition temperature. A method for thermally decomposing CFCs or the like. 2. The decomposition chamber according to claim 2, wherein the decomposition chamber is formed at least in two stages before and after a first decomposition chamber and a second decomposition chamber connected in series, and the temperature is raised to the decomposition temperature in the first decomposition chamber. A method for thermally decomposing chlorofluorocarbons and the like, wherein chlorofluorocarbons and the like are heated again to a decomposition temperature in a decomposition chamber in a subsequent stage. 3. A method for thermally decomposing fluorocarbon or the like according to claim 2, wherein the operating volume of the former decomposition chamber is set larger than the operating volume of the latter decomposition chamber. 4. A method for pyrolyzing CFCs or the like according to claim 2, wherein the former decomposition chamber is constituted by a plurality of decomposition chambers, and at least the number of the former decomposition chambers is set to be larger than the number of the latter decomposition chambers. 5. A combustion chamber of an internal combustion engine disposed at a front stage and a decomposition chamber constituted by a compression chamber of a positive displacement compressor disposed at a rear stage are connected in series, and Freon and the like are taken in together with fuel as intake air of the internal combustion engine. A pyrolysis device such as chlorofluorocarbon which is introduced into the passage and adiabatically compresses decomposition gas such as chlorofluorocarbon discharged together with the exhaust gas from the exhaust passage of the internal combustion engine to the decomposition temperature of fluorocarbon again in the decomposition chamber. 6. A CFC having a cylinder block in which a plurality of compression chambers each having a piston and a cylinder are formed, a part of which is a combustion chamber of an internal combustion engine, and the remaining compression chamber is a decomposition chamber such as CFC. Such as pyrolysis equipment.