JPH1067880A - Method and apparatus for collecting foamed gas in thermal insulation - Google Patents

Abstract

(57) Abstract: Provided is an apparatus for degassing and collecting remaining foaming gas such as chlorofluorocarbon by destroying a film that forms bubbles to convert closed cells into open cells. A high-speed rotary crusher applies a dynamic external force such as a shearing force or an impact force to a heat insulating material to break closed cells, thereby separating and collecting resin and gas in the bubbles. The foaming agent can be separated and recovered from a heat insulating material such as hard foamed polyurethane without dispersing fluorocarbons and the like into the atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating unnecessary foam insulation used in refrigerators and the like, and more particularly to a method and an apparatus for recovering chlorofluorocarbon from rigid polyurethane foam using chlorofluorocarbon as a foaming agent. It is.

[0002]

2. Description of the Related Art Insulation materials such as refrigerators are made of CFC11 or CFC11.
Specific Freon such as FC114, or HCFC142
Manufactured from plastics using alternative CFCs as blowing agents. Since these chlorofluorocarbons may destroy the ozone layer, the use of the specified chlorofluorocarbon will be discontinued by the end of 1995, and the consumption of alternative fluorocarbons will be regulated in 1996. However, no consideration has been given to the treatment of the chlorofluorocarbon (hereinafter simply chlorofluorocarbon) in the used heat insulating material.

Conventionally, a used foamed heat insulating material has a particle size of 3 m as disclosed in, for example, JP-A-2-144183.
m or less, and then pressurized and compressed to a pressure of 140 kg / cm ² or more with a cylinder-type volume reducer or the like to reduce the volume and solidify.
Landfilled or incinerated. In this case, no consideration was given to measures such as CFCs remaining in the insulation,
There is a problem that a part of the gas is released into the atmosphere, which may destroy the environment.

As a countermeasure, a method of compressing a coarsely crushed heat insulating material with a press or the like to degas and collect remaining Freon has been attempted.

[0005]

However, as a result of experiments conducted by the present inventors on the above prior art, it was found that degassing was not possible even when a compressive load of about 5 tons was applied to a 50 mm cubic rigid foamed polyurethane insulation. . This is made of foamed polyurethane made of closed cells with a cell diameter of several hundred μm.
It is considered that the film that forms bubbles cannot be destroyed only by compression.

An object of the present invention is to provide a method and an apparatus for efficiently recovering harmful foamed gas in foamed heat insulating material.

[0007]

A feature of the present invention is that a foamed heat insulating material made of hard urethane foam using freon as a foaming agent and used as a heat insulating material for equipment is charged into a crusher, and the shearing force is applied by the crusher. In the method of recovering the foamed gas, wherein the foamed heat insulating material is finely pulverized to separate and collect the CFCs contained in the closed cells in the foamed heat insulating material. The closed cells in the foamed heat insulating material were broken by finely pulverizing to a particle size of ~ 2.0 mm, and the fine bubbles of the foamed heat insulating material and the closed cells of the foamed heat insulating material were destroyed. A method for recovering foamed gas in a heat insulating material by separating and liquefying and recovering CFCs.

[0008]

By applying a dynamic external force such as a shearing force or an impact force to the foamed heat insulating material by a crusher, the closed cells are broken and the resin and the gas in the bubbles are separated. By collecting and separating and liquefying the chlorofluorocarbon generated along with the destruction of the closed cells from the finely pulverized material, harmful fluorocarbon gas in the foamed heat insulating material can be efficiently collected.

[0009]

FIG. 1 shows a basic flow of one embodiment of the present invention. In the figure, reference numeral 1 denotes a foamed heat insulating material to be treated, which is separated and collected into a fine resin 2 and a liquefied foamed gas 3 as described below. Reference numeral 10 denotes a supply section of the heat insulating material 1, 30 denotes a crushing section of the heat insulating material, and 40 denotes a separation section of the crushed resin and the foaming gas. Reference numeral 93 denotes a pipe through which a gas containing the separated foamed gas and entrained air passes, 93A denotes a branch pipe for returning a part of this gas to the supply unit 10, and 93B denotes a branch pipe that guides another part of the gas to the cooling and liquefaction unit 60. It is.

The foamed heat insulating material 1 to be treated is filled in a sealed supply section 10 and sent to a pulverizing section 30 in which closed cells are broken by a dynamic external force such as a shearing force or an impact force. Further, the resin 2 and the gas in the bubbles are separated in the separation unit 40, and the separated gas containing the foamed gas and the entrained air is returned to the supply unit 10 through the pipe 93 and the branch pipe 93A, and the foamed gas concentration in the gas is returned. Enhance. The gas whose foaming gas concentration has been increased in this manner is extracted from the branch pipe 93B, cooled in the cooling liquefaction unit 60 and liquefied to form the foamed gas 3. In this way, the foamed heat insulating material 1 is separated and collected into the fine resin 2 and the liquefied foamed gas 3.

FIG. 2 shows a more detailed configuration of the embodiment of the present invention. The supply hopper 11 of the supply unit 10 is partitioned by the inlet 12 for the object to be processed and the gate valve 13 so as to seal the object to be processed from the outside and guide the object to be supplied to the supply screw 18. The rotor 3 of the high-speed rotary crusher 31 constituting the crushing unit 30 in the vicinity of the outlet of the supply screw 18
2 are installed. A screen 33 is provided below the rotor 32, and a partition cylinder 34 is provided at the lower hopper 3.
5 is provided inside.

The bag filter 41 constituting the separating section 40 has a fan 42 at its upper part, and is connected to the lower hopper 34 by a side pipe 43 and a bottom pipe 44. On the other hand, the upper part of the bag filter 41 is connected to the supply hopper 11 and the compressor 6 via a pipe 93 and branch pipes 93A and 93B.
1 connected. The compressor 61, the first condenser 62, and the second condenser 63 constitute a cooling and liquefaction unit 60, and are connected therebetween by pipes 94 and 95, respectively. The lower part and the lower part are connected to the supply hopper 11 and the condensate collection tank 81 by pipes 96 and 97, respectively. Reference numeral 71 denotes a screw for reducing the volume of the finely ground resin 2. Then, the first condenser 61 and the second condenser 62 are cooled to predetermined temperatures by the refrigerant supply devices 64 and 65, respectively. As the compressor 51, a reciprocating type or a rotary type is used, and a closed type is particularly recommended.

In such an apparatus, the article 1 to be treated, such as a rigid foamed polyurethane insulation, is pre-treated in advance and is about 5 c
It is crushed to the size of m square. Then, the hopper 11 is filled into the supply hopper 11 through the gate valve 13 through the inlet 12, and guided to the high-speed rotary crusher 31 of the crushing unit 30 by the supply screw 18. Here, the workpiece 1 is pulverized by the shearing and impact action by the rotor 32, and the closed cells forming the heat insulating structure are destroyed.

By crushing the object 1 to a particle size of 2 to 3 times or less the diameter d of the closed cells, the closed cells in the heat insulating material are almost destroyed.

That is, as shown in FIG.
0.1 to 1.0 whose outer shell is made of urethane resin 112
It has a number of closed cells 111 having an inner diameter of mm, and a foaming gas such as chlorofluorocarbon is confined in the closed cells. Then, when a shearing force is applied to the heat insulating material, as shown by a dotted line 113 in the figure, a crack is formed or divided, and the Freon in each closed cell 111 is discharged. At this time, the particle size of the crushed pieces is 0.2 to 2.0 mm.

The crusher 31 has a fixed blade 36 having a sawtooth shape and a rotary blade 37 having a plate shape, as shown in FIG. The heat insulating material 1 is pressed (approximately 1 to 2 mm) into the gap between the tip of the rotary blade and the fixed blade, and is cut into the above-mentioned size by a shearing force. If the insulation is hard foam polyurethane,
The magnitude of the shearing force is 1000 / s or more, preferably 50 / s.
00 / s to 50,000 / s. In the example of FIG. 4, the necessary shearing force can be obtained by setting the rotating blade to about 3000 rpm.

The crusher need not be limited to a rotary type. For example, a pair of rotors each having a rotary blade on its outer periphery are arranged in parallel, and an impact force is applied to the heat insulating material between the rotary blades. Any material that can apply a dynamic external force to the heat insulating material, such as an impact crusher, may be used.

Returning to FIG. 2, a screen 33 having a hole of about 3 mm square (or diameter) is provided at the lower part of the crusher 31, and the crusher 31 crushes the heat insulating material to about 2 mm or less. Only the pieces fall, and the larger pieces are again crushed by the shearing force applied by the rotor 32.

The rotary blade 37 of the rotor 32 also has a function of a blower for sending gas and air in the supply hopper 11 and the crusher 31 to the bag filter 41.

If the crusher does not have a sufficient air blowing function such as a screw type, a mixer type or a cutter type, it is preferable to provide an independent blower upstream or downstream of the crusher.

Foaming gas such as chlorofluorocarbon generated by pulverizing the heat insulating material by the pulverizer 31 passes through the pipe 43 together with the entrained air taken in with the heat insulating material, and passes through the bag filter 4.
It is led to 1. The bag filter has a partition 45 made of cloth or ceramics, in which fine powder resin is separated and returned to the lower hopper 35 via a pipe 93, and gas is discharged to the pipe 93 by the fan 42.

At this time, since the foaming gas such as Freon contains air, the concentration of the gas in the gas is low. Then, the gas (F
A part (F3) of 1) returns to the supply hopper 11 through the branch pipe 93A, and the remaining part of the gas (F2) is sent to the compressor 61 through the branch pipe 93B. By providing such a reflux route, the concentration of the foaming gas in the gas can be increased. The gas containing the foaming gas is pressurized by the compressor 61 to 0.2 to 1.1 Pa, and as a result, the temperature becomes 40 to 50 ° C. Next, it is sent to the first condenser 62, cooled to 10 ° C. to 20 ° C. by cooling water or the like, and
Led to.

In the second condenser 63, the gas containing the foaming gas is further cooled to about -30 ° C. by a refrigerant or the like.
The foaming gas is liquefied, settled and separated in the collection tank 81, and collected as the liquefied foaming gas 3. In addition, a part of the non-condensable gas such as air entrained in the foaming gas and not condensed is returned to the supply hopper 11 through the pipe 96, and is again returned to the high-speed rotary pulverizer 31 together with the object. Sent to In this way, the foaming gas is concentrated by the gas generated from the object to be processed which is newly pulverized while circulating in the present apparatus, becomes a high concentration, and is easily condensed and liquefied. That is, it can be liquefied at low pressure and high temperature.

The operating conditions differ depending on the amount of foaming gas and the amount of entrained air, but the concentration of the concentrated foaming gas is 20 to 50 Vo.
0.2% -1.1Pa at 1%, liquefaction temperature 0-50C
It is.

On the other hand, the fine resin 2 crushed by the high-speed rotary crusher 31 is pushed up by the volume reducing screw 71 to separate the foaming gas and take out only the fine resin 2 out of the system.

In the apparatus of the present embodiment, the rigid foamed polyurethane insulation is treated at a processing rate of 20 kg / h, and the pipe 91
Circulating gas flow rate F1 = 30Nm ³ / h, branch pipe 93
The circulating gas flow rate F3 in A is 28.6 Nm ³ / h, the gas flow rate F2 in the branch pipe 93B is 1.4 Nm ³ / h, and the composition of the circulating gas is 40 Vo1% Freon (60 V air).
o1%), about 90% of the CFC in the foamed polyurethane could be liquefied and recovered.

As described above, the CFCs in the foamed polyurethane are degassed from the urethane by destroying the closed cells, and then are collected without being released into the atmosphere by cooling and liquefying the degassed gas. Can be.

According to a more preferred embodiment of the present invention, an intermediate tank 14 is provided between the supply hopper 11 and the inlet 12 as shown in FIG. 63 and the intermediate tank 14 are connected by a pipe 96. In this embodiment, the rotary valves 15 and 16 can be used to separate the supply hopper 11 and the inlet 12 where the foaming gas has a high concentration, thereby preventing the foaming gas from flowing back to the inlet 12 due to backflow. The low-concentration foamed gas from the condenser 63 is supplied to the intermediate tank 1.
By returning to 4, the foaming gas in the supply hopper 11 can be maintained at a high concentration.

According to another recommended embodiment, a pipe 97 is provided above the intermediate tank 14 and connected to the adsorption tower 101 as shown in FIG. In this embodiment, the air flowing along with the object 1 supplied from the rotary valve 15 can be discharged out of the system from the pipe 97 as a vent gas. At this time, the foaming gas accompanying the vent gas is removed by the adsorption tower 101. Can be collected. By such a method, the recovery rate of CFCs in the foamed polyurethane can be further increased.

According to still another embodiment, as shown in FIG. 7, a gas is circulated between a supply screw 18 and a high-speed rotary crusher 31 by connecting a branch pipe 93A and a pipe 96. . In the present embodiment, the supply screw 1
In 8, the air that has flowed in along with the object to be processed is escaped to the rear and separated, so that the amount of the entrained air can be reduced and the gas can be circulated. Further, as the rotary pulverizer 31, a two-shaft meshing type can be used.

According to still another embodiment, as shown in FIG. 8, a flow control valve 98 is provided in a branch pipe 93B, and a fluorocarbon concentration sensor 99 is attached to the branch pipe 93A to control the controller 20.
It is conceivable that the opening degree of the flow control valve 98 is changed according to 0 according to the CFC concentration in the branch pipe 93.

In the embodiment of FIG. 8, as shown in FIG. 9, when the chlorofluorocarbon concentration at the start of operation is low, the flow control valve 98 is throttled to reduce the flow rate F2 and increase the circulating flow rate F3 to increase the chlorofluorocarbon concentration. By controlling the flow rate control valve 98 to open and increase the flow rate F2 when the time has elapsed and the Freon concentration has risen, efficient operation can be performed at a predetermined concentration.

The present invention relates to a case where the gas used for foaming is to be recovered from the viewpoint of environmental destruction, such as chlorofluorocarbon and alternative chlorofluorocarbon, among the heat insulating materials made using a foaming agent. It is effective when used.

Further, as the material of the solid phase portion of the heat insulating material, in addition to the resins described in the embodiments, a material using a polymer material other than ceramic can be applied.

As means for pulverizing the heat insulating material, means other than rotational force such as a combination of low-temperature freezing and impact force may be used.

[0036]

According to the present invention, the foaming gas contained in the heat insulating material such as rigid foamed polyurethane can be separated and recovered without fail.
There is an effect that harmful gases such as chlorofluorocarbons are not released into the atmosphere.

[Brief description of the drawings]

FIG. 1 is a basic flow sheet of one embodiment of the present invention.

FIG. 2 is a diagram showing details of the embodiment of FIG. 1;

FIG. 3 is an enlarged view showing a configuration of a foamed heat insulating material.

FIG. 4 is a cross-sectional view of a main part of a pulverizing unit in FIG. 2;

FIG. 5 is a partial sectional view showing another embodiment of the present invention.

FIG. 6 is a partial sectional view showing still another embodiment of the present invention.

FIG. 7 is a partial sectional view showing still another embodiment of the present invention.

FIG. 8 is a flow sheet showing still another embodiment of the present invention.

9 is an explanatory diagram of a circulation flow rate adjusting method in the embodiment of FIG.

[Explanation of symbols]

11: Supply hopper, 18: Supply screw, 31: High-speed rotary crusher, 41: Bag filter, 62: Compressor,
63: first condenser, 64: second condenser, 71: reduced volume screw, 81: collecting tank for condensed liquid, 93: pipe through which gas containing separated foamed gas and entrained air passes, 93A: one of gas A branch pipe for returning the section to the supply section, a branch pipe for guiding the other part of the gas to the cooling and liquefaction section.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshiyuki Takamura 794 Higashi-Toyoi, Katsumatsu-shi, Yamaguchi Prefecture Inside the Kasado Plant of Hitachi Ltd. Inside the Todo Factory (72) Inventor Nobuo Kimura 502 Kandachi-cho, Tsuchiura City, Ibaraki Prefecture Inside the Machine Research Laboratories, Hitachi, Ltd.

Claims (8)

[Claims] 1. A foamed heat insulating material made of hard urethane foam using freon as a foaming agent and used as a heat insulating material for equipment is charged into a crusher, and a shear force is applied by the crusher to finely disperse the foamed heat insulating material. In a method for recovering a foaming gas for crushing and separating and recovering CFCs contained in closed cells in the foamed heat insulating material, a shear force is applied to the foamed heat insulating material to produce a foamed gas having a thickness of 0.2 to 2.0 m.
The closed cells in the foamed heat insulating material are destroyed by finely pulverizing the foamed heat insulating material, and the finely pulverized material of the foamed heat insulating material is separated from the CFC generated due to the destruction of the closed cells of the foamed heat insulating material. A method for recovering foamed gas in a heat insulating material, which comprises liquefying and recovering. 2. A foamed heat insulating material, which is made of hard urethane foam using freon as a foaming agent and is used as a heat insulating material for equipment, is charged into a crusher, and the crusher applies a shearing force to finely disperse the foamed heat insulating material. A method for recovering a foaming gas, which comprises crushing and separating and recovering CFCs contained in closed cells in the foamed heat insulating material, wherein a shear force is applied to the foamed heat insulating material to three times the diameter of the closed cells in the foamed heat insulating material. The closed cells in the foamed heat insulating material are destroyed by finely pulverizing to the following particle size, and the finely pulverized material of the foamed heat insulating material is separated from CFCs generated due to the breakage of the closed cells of the foamed heat insulating material. A method for recovering foamed gas in a heat insulating material, which comprises liquefying and recovering. 3. A foam insulating material, which is made of hard urethane foam using freon as a foaming agent, and is used as a heat insulating material for equipment, is charged into a crusher, and a shear force is applied by the crusher to finely disperse the foam insulating material. A method for recovering a foaming gas, which comprises crushing and separating and recovering CFCs contained in closed cells in the foamed heat insulating material, wherein a shear force is applied to the foamed heat insulating material to double the diameter of the closed cells in the foamed heat insulating material. The closed cells in the foamed heat insulating material are destroyed by finely pulverizing to the following particle size, and the finely pulverized material of the foamed heat insulating material is separated from CFCs generated due to the breakage of the closed cells of the foamed heat insulating material. A method for recovering foamed gas in a heat insulating material, which comprises liquefying and recovering. 4. A foam insulating material, which is made of hard urethane foam using freon as a foaming agent and is used as a heat insulating material for equipment, is charged into a crusher, and a shear force is applied by the crusher to finely form the foam insulating material. In a method for recovering a foaming gas for crushing and separating and recovering chlorofluorocarbon contained in closed cells in the foamed heat insulating material, the foamed heat insulating material is contained in the foamed heat insulating material charged into the crusher by applying a shearing force to the foamed heat insulating material. 90% or more of the closed cells are destroyed, and the finely pulverized foam insulation and the fluorocarbon generated due to the destruction of the closed cells of the foam insulation are separated and liquefied and collected. A method for recovering foamed gas in a heat insulating material. 5. A foam insulating material made of hard urethane foam using freon as a foaming agent and used as a heat insulating material for equipment is charged into a crusher, and a shear force is applied by the crusher to finely disperse the foam insulating material. In a foaming gas recovery device that pulverizes and separates and collects CFCs contained in closed cells in the foamed heat insulating material, a shear force is applied to the foamed heat insulating material to finely pulverize to a particle size of 0.2 to 2.0 mm. A crusher that breaks closed cells in the foamed heat insulating material, and separates and liquefies the finely pulverized material of the foamed heat insulating material and CFCs generated due to the breakage of the closed cells of the foamed heat insulating material. An apparatus for recovering foamed gas in a heat insulating material, comprising a recovery means for recovering the foamed gas. 6. A foam insulating material made of hard urethane foam using freon as a foaming agent and used as a heat insulating material for equipment is charged into a crusher, and a shear force is applied by the crusher to finely form the foam insulating material. In a foaming gas recovery device for crushing and separating and recovering CFCs contained in closed cells in the foamed heat insulating material, a shear force is applied to the foamed heat insulating material to triple the diameter of the closed cells in the foamed heat insulating material. A crusher for breaking closed cells in the foamed heat insulating material by finely pulverizing the foamed heat insulating material, a finely pulverized product of the foamed heat insulating material, and CFCs generated with the breaking of the closed cells of the foamed heat insulating material And a collecting means for separating and liquefying the gas and recovering the foamed gas. 7. A foam insulating material, which is made of hard urethane foam using freon as a foaming agent and is used as a heat insulating material for equipment, is charged into a crusher, and a shear force is applied by the crusher to finely disperse the foam insulating material. A foaming gas recovery apparatus for crushing and separating and recovering CFCs contained in closed cells in the foamed heat insulating material, wherein a shear force is applied to the foamed heat insulating material to double the diameter of the closed cells in the foamed heat insulating material. A crusher for breaking closed cells in the foamed heat insulating material by finely pulverizing the foamed heat insulating material, a finely pulverized product of the foamed heat insulating material, and CFCs generated with the breaking of the closed cells of the foamed heat insulating material And a collecting means for separating and liquefying the gas and recovering the foamed gas. 8. A foam insulating material made of hard urethane foam using freon as a foaming agent and used as a heat insulating material of equipment is charged into a crusher, and a shear force is applied by the crusher to finely disperse the foam insulating material. In a foaming gas recovery device that pulverizes and separates and recovers CFCs contained in closed cells in the foamed heat insulating material, the foamed heat insulating material is subjected to a shearing force to be included in the foamed heat insulating material charged into the crusher. A crusher that breaks up 90% or more of the closed cells, a finely pulverized product of the foamed heat insulating material, and separates and liquefies and collects CFCs generated by the breakage of the closed cells of the foamed heat insulating material. An apparatus for recovering foamed gas in a heat insulating material, comprising: a recovery unit.