JP2010121091A - Apparatus and method for treating waste plastics - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for treating waste plastics that can largely reduce the amount of chlorine components mixed into a recovered oil although it has a simple construction and to provide a method for treating waste plastics. <P>SOLUTION: The apparatus for treating waste plastics is designed for the pyrolysis of waste plastics as a resource having the possibility of being mixed with vinyl chloride and other chlorine-containing plastics. The apparatus has a pyrolysis unit where the target waste plastics as a resource to be treated are introduced and the introduced waste plastics are pyrolyzed, a treatment unit for dechlorination and a treatment unit for condensing oils where the pyrolysis gas discharged from the pyrolysis unit is treated. The pyrolysis unit is constructed such that the waste plastics as a resource are pyrolyzed at least at a first temperature and a second temperature higher than the first temperature and a guide passage for the pyrolysis gas discharged from the pyrolysis unit is provided with a switching means for guiding the pyrolysis gas such that the pyrolysis gas produced at the first temperature is guided into the treatment unit for dechlorination and the pyrolysis gas produced at the second temperature is guided into the treatment unit for condensing oils. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a waste plastic processing apparatus and a processing method capable of thermally decomposing waste plastic containing polyvinyl chloride and other chlorine-containing plastics such as vinylidene chloride and recovering hydrocarbon oil. In particular, by detecting the concentration of hydrogen chloride and chlorine compounds in the pyrolysis gas generated by thermal decomposition, waste plastic processing equipment that prevents the chlorine compounds from being mixed into the hydrocarbon oil that is the recovered decomposition product, and It relates to the processing method.

  Conventionally, incineration processing, landfill processing, and the like have been performed as disposal methods for waste plastics. However, in the combustion process, there are problems that harmful gas is generated along with combustion and that the life of the incinerator is shortened because of the high calorific value at the time of combustion. In landfill processing, in addition to the problem of environmental pollution, there was a problem of tightness in landfills, especially in urban areas. Furthermore, the necessity of recycling waste plastics is increasing year by year from the viewpoint of effective use of resources.

  In this background, waste plastic recycling technology has been proposed in recent years. In this method, waste plastic is pyrolyzed, and hydrocarbon oil and the like are recovered from the pyrolysis gas generated by this process.

  However, the plastics that are subject to thermal decomposition are limited to polyolefins such as polyethylene and polypropylene, and polystyrene. Thermoplastic resins other than polyolefins, especially hydrogen chloride gas during heating such as polyvinyl chloride, are used. There have been various problems in expanding to plastics that generate toxic gases. Specifically, since the concentration of generated hydrogen chloride increases as the amount of polyvinyl chloride mixed in increases, problems such as corrosion of the metal parts of the processing equipment, and There was a problem that chlorine compounds were mixed.

  In order to enable such thermal decomposition treatment of vinyl chloride resin and the like, conventionally, a method for improving the corrosion resistance of a combustion treatment (incineration) apparatus, and an acid neutralizing agent such as a basic compound are mixed in advance during the thermal decomposition treatment. Method (Patent Document 1: Japanese Patent Application Laid-Open No. 48-23873), a method of removing HCl gas generated by thermal decomposition into a solid chloride by reaction with a desalting agent and removing it from the decomposition gas (Patent Document) 2: JP-A-07-166171), and prior to thermal decomposition, the processed product is subjected to thermal pyrolysis stepwise to recover hydrogen chloride, and then thermal pyrolysis to recover oil and gas not containing chlorine. (Patent Document 3: Japanese Patent Application Laid-Open No. 5-245463) has been proposed.

  Further, in the problem caused by the method described in Patent Document 3, that is, in the thermal decomposition of a mixed plastic containing vinyl chloride resin, chlorine compounds are generated even in a temperature range higher than the temperature range where hydrogen chloride gas is generated. There is a problem that mixing into the inside cannot be completely prevented, and Patent Document 4 (Japanese Patent Laid-Open No. 08-239671) has also been proposed to solve such a problem.

In Patent Document 4, by providing a halogen fixing means between the thermal decomposition means and the catalytic catalyst reaction means, it is possible to prevent a decrease in the activity of the catalyst due to halogen and maintain stable catalyst performance.
Japanese Patent Laid-Open No. 48-23873 Japanese Patent Application Laid-Open No. 07-166171 JP-A-5-245463 Japanese Patent Laid-Open No. 08-239671

  From the viewpoint of recycling waste plastic, it is desirable that the hydrocarbon oil as the decomposition product should be sufficiently usable. For this purpose, the chlorine compound content in the hydrocarbon oil needs to be kept below a certain level. This is because if a large amount of chlorine compound is mixed in the hydrocarbon oil, problems such as corrosion of combustion equipment and generation of harmful gases occur when the hydrocarbon oil is reused as fuel. It is.

  In this regard, in Patent Document 4, a halogen immobilization means is provided between the thermal decomposition means and the catalytic catalyst reaction means in order to more reliably prevent chlorine from being mixed into the recovered oil. However, in such a configuration, there is a problem that the apparatus is large and the processing system becomes complicated, resulting in an increase in facility input cost and running cost.

  Therefore, an object of the present invention is to propose a waste plastic processing apparatus and a processing method capable of greatly suppressing the amount of chlorine compounds mixed in the recovered oil while having a simple configuration.

  Furthermore, even if the configuration is simplified, hydrogen chloride contained in the pyrolysis gas of the waste plastic must be reliably recovered from the viewpoint of environmental protection.

  Accordingly, the second object of the present invention is to propose a waste plastic processing apparatus and a processing method capable of detoxifying and recovering hydrogen chloride and chlorine compounds generated from the pyrolysis gas of waste plastic.

  In order to solve at least one of the above-described problems, the present invention performs thermal decomposition of waste plastic in two stages, incinerates a low-temperature side pyrolysis gas that can be mixed with hydrogen chloride, and then follows a high-temperature side pyrolysis gas. The present invention provides a waste plastic processing apparatus for recovering hydrocarbon oil from sewage.

  That is, in the present invention, in order to solve at least one of the above-mentioned problems, a waste plastic resource to be processed is input, a thermal decomposition unit that thermally decomposes the input waste plastic resource, and is discharged from the thermal decomposition unit. A waste plastic processing device that decomposes waste plastic resources that may contain vinyl chloride and other chlorine-containing plastics. In the guide path of the pyrolysis gas discharged from the pyrolysis section, a hydrogen chloride measuring device that detects the hydrogen chloride concentration in the pyrolysis gas, and a guide direction of the pyrolysis gas discharged from the pyrolysis section Provided is a waste plastic processing apparatus provided with a pyrolysis gas switching means for switching to a dechlorination processing section or an oil condensation processing section.

  In the waste plastic processing apparatus of the present invention, waste plastic resources to be processed at a time are put together in a thermal decomposition section (particularly, a thermal decomposition tank described later), and desalted and hydrocarbon oil recovery is performed on the input waste plastic resources. Since the batch type is used, the pyrolysis gas guide direction can be switched to the dechlorination treatment section or the oil content condensation treatment section according to the measurement result in the hydrogen chloride measuring device, and as a result, recovered. Mixing of chlorine compound components into the hydrocarbon oil can be significantly reduced. Here, the batch type is a term for the continuous type, which is also referred to as a batch processing type or an intermittent type, and refers to a type in which materials are stored to some extent in the thermal decomposition pot constituting the thermal decomposition unit.

  Then, the hydrogen chloride concentration in the pyrolysis gas is detected by a hydrogen chloride measuring device, and on the basis of the detection result, the guide direction of the pyrolysis gas discharged from the thermal decomposition section by the pyrolysis gas switching means is set as the dechlorination section. Since switching is performed between the oil condensing unit and the hydrocarbon component recovered in the oil condensing unit, mixing of chlorine compound components can be significantly reduced.

  The waste plastic resources to be treated by the waste plastic treatment apparatus according to the present invention include a collection of vinyl chloride and other chlorine-containing plastics, a mixture of chlorine-containing plastics, and a mixture of chlorine-containing plastics. Including those that are not.

  In addition, it is desirable to collect the hydrocarbon oil recovered by condensing the pyrolysis gas separately for heavy oil and light oil in the oil condensing unit, but recovering it as an oil component without separating both. Is also possible.

  The thermal decomposition unit is for thermally decomposing the waste plastic resource that has been input, and can be composed of a thermal decomposition kettle having an input port for introducing the waste plastic resource, a burner for heating the thermal decomposition kettle, and the like. . This pyrolysis kettle is provided with a discharge port to a path (pipeline or the like) that guides the pyrolysis gas generated by the thermal decomposition to the dechlorination processing unit or the oil content condensation processing unit.

  In the waste plastic processing apparatus according to the present invention, chlorine or chlorine compound components are removed from the waste plastic resource, and in order to recover high-quality hydrocarbon oil in which the amount of such contamination is minimized, It is desirable to adjust the temperature of the thermal decomposition. That is, hydrogen chloride or chlorine compound components are mixed in pyrolysis gas (hereinafter referred to as “inappropriate gas”) generated by thermal decomposition at about 300 ° C. to less than 350 ° C., and this unsuitable gas is desalted. And measure with a hydrogen chloride measuring device whether hydrogen chloride or a chlorine compound component is not mixed in the pyrolysis gas generated by the thermal decomposition, or the mixed amount is less than a specified value, and the chlorine compound At the stage where the concentration of the resin meets the standard, the temperature of the thermal decomposition of the waste plastic resource in the thermal decomposition section can be raised. That is, by adjusting the temperature of the thermal decomposition in the thermal decomposition section, separating the pyrolysis gas containing hydrogen chloride or chlorine compound component and the pyrolysis gas greatly reducing the mixing amount of hydrogen chloride or chlorine compound component. Can do.

  Therefore, in the present invention, in order to solve at least one of the above-described problems, a waste plastic resource to be processed is input, a thermal decomposition unit that thermally decomposes the input waste plastic resource, and a discharge from the thermal decomposition unit. A waste plastic processing apparatus for pyrolyzing waste plastic resources that may contain vinyl chloride and other chlorine-containing plastics, comprising a dechlorination treatment section and an oil condensation treatment section for treating the pyrolysis gas to be produced, The thermal decomposition unit includes a temperature adjusting means for adjusting a temperature at which the waste plastic resource is thermally decomposed to a first temperature and a second temperature higher than the first temperature, and from the thermal decomposition unit, A hydrogen chloride measuring device that detects the concentration of hydrogen chloride in the pyrolysis gas is provided in the guide path of the pyrolysis gas discharged, and the temperature adjusting means Based on the measurement result of the hydrogen fluoride measuring device, the first temperature and the second temperature are switched, and the pyrolysis gas generated at the first temperature is guided to the dechlorination section in the pyrolysis gas guide path. And the waste plastic processing apparatus provided with the pyrolysis gas switching means which guides the pyrolysis gas generated at the second temperature to the oil condensation processing section is provided.

  In the waste plastic processing apparatus, the thermal decomposition unit is configured to be able to heat at least the first temperature and the second temperature higher than the first temperature. Specifically, for example, the output of a heating means such as a burner can be freely adjusted. It is also conceivable to adjust the heating time. In order to reduce the mixing of chlorine components such as chlorinated compounds into the hydrocarbon oil as much as possible, the first temperature is adjusted to less than about 350 ° C., and the second temperature is about 350 ° C. or higher, preferably about 400 ° C. to 500 ° C. It is desirable to adjust to. The first temperature and the second temperature can be set as the temperature at the discharge port in addition to determining the temperature in the pyrolysis kettle.

  The pyrolysis gas switching means is configured as a switching valve in addition to being configured as a valve installed in at least one of a path from the thermal decomposition section to the dechlorination processing section and a path from the thermal decomposition section to the oil condensation processing section. be able to. Furthermore, temperature detection means for detecting the temperature for controlling the opening and closing of the pyrolysis gas switching means can be provided in the vicinity of the outlet of the pyrolysis gas discharged from the thermal decomposition section.

  The dechlorination unit includes a combustion furnace for burning the pyrolysis gas discharged from the thermal decomposition unit, a cooling device for cooling the exhaust gas discharged from the combustion furnace, and neutralizing the exhaust gas that has passed through the cooling device. And an absorbing device to be configured.

  The combustion furnace burns the pyrolysis gas generated at the first temperature and removes organic components. The cooling device suppresses the generation of dioxins and absorbs hydrogen chloride in the next absorption device. This is an apparatus for cooling the exhaust gas discharged from the combustion furnace in order to perform the above. In the absorption device, hydrogen chloride contained in the exhaust gas is dissolved in water, and is neutralized by bringing it into contact with alkali so that it can be drained. In particular, the absorption device is formed such that water neutralized by adding alkali is circulated and brought into contact with hydrogen chloride, so that the amount of drainage can be greatly reduced. In addition, this waste water can also be used as the cooling water in the said cooling device as needed. Further, in the desalination treatment, the hydrocarbon oil that can be contained in the pyrolysis gas can be removed by burning the pyrolysis gas discharged from the thermal decomposition section in the combustion furnace. By neutralizing the pyrolysis gas after the removal, it is possible to eliminate contamination of water to which alkali used for neutralization is added.

  In addition, the oil condensing processing unit includes a first oil condenser that cools the pyrolysis gas discharged from the heat decomposition unit and recovers heavy oil, and a pyrolysis discharged through the heavy oil recovery device. A second oil condenser that cools the gas and recovers light oil and a flare stack that incinerates the uncondensed gas that has passed through the light oil recovery device, and further heats the light oil recovered by the second oil condenser. It can comprise as a fuel supply line led to a decomposition part. The first oil condenser and the second oil condenser have different cooling temperatures of the pyrolysis gas, and when the first oil condenser collects heavy oil, the first oil condenser The pyrolysis gas generated during the thermal decomposition at about 350 ° C. or higher, preferably about 400 ° C. to 500 ° C. is cooled to about 150 ° C. Thereby, the heavy oil which is liquid at the temperature can be recovered. On the other hand, when the second oil condenser collects light oil, the second oil condenser cools the pyrolysis gas cooled to about 150 ° C. by the first oil condenser to about 40 ° C. or less. . Thereby, the light oil which is liquid at the temperature can be recovered. Of course, when the components other than chlorine are recovered, the first temperature and the second temperature can be appropriately adjusted.

The first and second oil condensers spray a heat exchange tube (tube heat exchanger) in which cooling water circulates inside and a hydrocarbon oil produced by each oil condenser into the pyrolysis gas. It is desirable to comprise as a spraying device (shell type heat exchanger). By using a tube-type heat exchanger and a shell-type heat exchanger, the production efficiency (ie, condensation efficiency) of hydrocarbon oil (heavy oil and light oil) can be greatly improved, and the equipment can be downsized. Can be planned.
The hydrogen chloride measuring device can be provided in a guide path for guiding the pyrolysis gas to a dechlorination processing section for processing the pyrolysis gas, or in a guide path for the pyrolysis gas in the dechlorination processing section. In particular, the detection part of the hydrogen chloride measuring device is a guide path for the pyrolysis gas in the dechlorination section, and is preferably installed in the guide path after the pyrolysis gas is burned, and more preferably It is desirable to install in the guide path after cooling the pyrolysis gas. Since the pyrolysis gas contains not a little hydrocarbon oil component, the hydrocarbon oil component is condensed in the detection part of the hydrogen chloride measuring device, and the detection accuracy of the hydrogen chloride measuring device is reduced. This is to prevent it.

  In the waste plastic processing apparatus of the present invention, it is desirable that the first oil condenser is provided with a temperature control device that keeps the temperature of the oil recovered in the condenser constant. This is for avoiding the mixing of other low-boiling components in the oil that can be recovered by the first oil condenser, and to make the quality constant.

The present invention also provides a waste plastic processing method for solving at least one of the above problems.
That is, a waste plastic processing method for recovering recycled oil from waste plastic resources that may contain vinyl chloride and other chlorine-containing plastics, wherein the waste plastic resources are thermally decomposed at a first temperature, and the first A demineralization treatment step in which pyrolysis gas generated by thermal decomposition at a temperature is incinerated, exhaust gas generated after incineration is cooled, and then neutralizing or adsorbing the hydrogen chloride component contained therein, and thermal decomposition After measuring the concentration of hydrogen chloride or chlorine compound in the pyrolysis gas generated in step 1 and the concentration of hydrogen chloride or chlorine compound in the pyrolysis gas falls below the standard value, The heat component after pyrolysis at a higher second temperature, the pyrolysis gas generated by the thermolysis is cooled in one or more stages to recover the regenerated oil, and the regenerated oil is recovered. Providing waste plastic processing method for incinerating gas.

According to the waste plastic processing apparatus and the processing method of the present invention, the following effects can be obtained.
That is, in order to remove pyrolysis gas that may be mixed with hydrogen chloride, first, pyrolysis is performed at around 300 ° C., and the pyrolysis gas generated at that temperature is removed without sending it to the oil condensation processing section. Desalination treatment is performed by sending it to the chlorination section. Then, the hydrogen chloride or chlorine compound concentration in the pyrolysis gas is monitored with a hydrogen chloride measuring device, and after the hydrogen chloride or chlorine compound concentration falls below the reference value, the pyrolysis gas is used to recover hydrocarbon oil. Supplied to the oil condensing unit. As a result, the pyrolysis gas after the desalting treatment, that is, the pyrolysis gas in which the amount of hydrogen chloride is greatly reduced is sent to the oil condensation treatment section, so that the chlorine compound that can be mixed in the hydrocarbon oil Is very small. Whether the pyrolysis gas is sent to the oil condensation processing section or the dechlorination processing section is monitored by a hydrogen chloride measuring device and also by controlling the temperature in the thermal decomposition section (or pyrolysis gas). Can do. And since the desalting process or the recovery of hydrocarbon oil is only by operating the pyrolysis gas switching means composed of valves, switching valves, etc., the waste plastic processing with a simple structure without complicated equipment The device is realized.

  And since the amount of chlorine compounds mixed in the hydrocarbon oil recovered by this waste plastic processing equipment and processing method is very small, even if hydrocarbon oil as a decomposition product is used as fuel, Corrosion and generation of harmful gases can be suppressed.

  Therefore, according to the present invention, it is possible to realize a waste plastic processing apparatus and a processing method capable of greatly suppressing the mixing of a chlorine compound into recovered oil while having a simple configuration.

  Furthermore, in the waste plastic processing apparatus and the processing method according to the present invention, the pyrolysis gas generated by the low temperature thermolysis to remove chlorine is incinerated in the dechlorination section and neutralized. Hydrogen chloride contained in the plastic pyrolysis gas can be recovered quickly and accurately. Thereby, the waste plastic processing apparatus and the processing method which can detoxify and collect | recover the hydrochloric acid produced | generated from the thermal decomposition gas of waste plastic are implement | achieved.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing the overall configuration of the waste plastic processing apparatus according to the present embodiment, FIG. 2 is a schematic diagram showing the configuration of the first and second oil condensers, and (A) shows the overall configuration. Schematic (B) is a schematic diagram showing a cooling portion.

  The waste plastic treatment apparatus according to this embodiment is roughly composed of two systems, a desalination treatment system and a waste plastic oil production system. The demineralization processing system surrounded by the chain line in FIG. 1 is configured by the dechlorination processing unit in the present invention, and the waste plastic oil generation system surrounded by the one-dot chain line in FIG. 1 is configured by the oil condensation processing unit. Yes. In particular, in this embodiment, a two-batch system comprising two systems (system A and system B) is adopted as the waste plastic oil production system. By adopting such a two-batch method, it is possible to improve the processing efficiency.

  The desalination treatment system (dechlorination treatment section) is referred to as “inappropriate gas” below because it contains pyrolysis gas (hydrogen chloride, chlorine compounds, etc.) discharged from the pyrolysis kettles 10A and 10B as the heat cracking section. ), A cooling tower 60 as a cooling device for cooling the exhaust gas discharged from the combustion furnace 50, and an absorption tower 70 as an absorption device for neutralizing the exhaust gas that has passed through the cooling device. Has been.

  The waste plastic oil production system (oil condensing unit) cools the pyrolysis gas discharged from the pyrolysis kettles 10A and 10B as the thermal decomposition unit and recovers heavy oil as a heavy oil condenser as the first oil condenser. The refined oil condensers 20A and 20B and the pyrolysis gas that has passed through the heavy oil condensers 20A and 20B (including light oil, hereinafter referred to as “light oil gas”) are cooled to recover the light oil. A light oil condenser 30A, 30B as a second oil condenser and a flare stack 40 for incinerating uncondensed gas (hereinafter referred to as “off-gas”) that has passed through the light oil recovery device are provided. One pyrolysis kettle 10A, 10B, heavy oil condensers 20A, 20B, and light oil condensers 30A, 30B are provided for each of the A system and the B system, and a flare stack 40 is provided for each system. One unit is provided to collect and burn off the generated off gas. In addition, the heavy oil recovered by the heavy oil condensers 20A and 20B in each system is recovered by the pipeline and heavy oil transfer pump for collecting the heavy oil in the heavy oil tank 21, and the light oil condensers 30A and 30B in each system. A pipeline for collecting the light oil collected in the light oil tank 90 and a light oil transfer pump are provided.

  Next, the overall flow of the waste plastic processing apparatus according to this embodiment will be described. First, the waste plastic raw material put into each of the pyrolysis kettles 10A and 10B is thermally decomposed at a first temperature of about 300 ° C. (at least less than 350 ° C.). In this embodiment, a burner is used as the heating means. Pyrolysis gas (unsuitable gas) generated by thermal decomposition at about 300 ° C. (at least less than 350 ° C.) is discharged from the respective thermal decomposition tanks 10A and 10B, but the desalting valve 11A provided in the guide path 11B is opened, and the oil valves 12A and 12B are closed to lead to a desalination treatment system (dechlorination treatment section). Inappropriate gas guided to the desalination system (dechlorination unit) is incinerated in the combustion furnace 50 at approximately 800 ° C. or higher. In the combustion furnace 50, secondary air is supplied by a blower in order to achieve combustion of the inappropriate gas.

  The exhaust gas discharged from the combustion furnace 50 is then cooled in the cooling tower 60. This is because hydrogen chloride and chlorine compounds contained in the exhaust gas are treated in the next absorption tower 70, but before that, a high-temperature (about 800 ° C. or higher) exhaust gas is suitable for treatment. This is because it is necessary to cool to below 150 ° C., preferably around 150 ° C. The cooling in the cooling tower 60 can be performed by water spray or the like in which water is sprayed into the exhaust gas guided into the cooling tower 60. The generation of dioxins can be suppressed by incinerating inappropriate gas at 800 ° C. or higher and cooling it to 200 ° C. or lower.

  And about the unsuitable gas burned in the combustion furnace 50, the content of hydrogen chloride or a chlorine compound is monitored in the stage before or after the above-mentioned cooling. In monitoring the content of hydrogen chloride or a chlorine compound, a hydrogen chloride measuring device is used. In this embodiment, a hydrogen chloride measuring device in exhaust gas (a model made by Toa DKK Corporation) is used as the hydrogen chloride measuring device. Name: GNC-224-1 etc.) can be used. In particular, in the present embodiment, the gas before or after the induction fan that guides the exhaust gas cooled by the cooling tower 60 into the absorption tower 70 is used as an unsuitable gas to be detected by the hydrogen chloride measuring device in exhaust gas. .

  The exhaust gas cooled to about 200 ° C. or less in the cooling tower 60 is guided into the absorption tower 70 by an induction fan. Hydrogen chloride or the like in the exhaust gas guided into the absorption tower 70 is absorbed by water sprayed from above (such as water adjusted to be alkaline) while passing through the filler 71. Since the sprayed water moves to the acidic side due to contact with hydrogen chloride or the like, alkali is added thereto. That is, the chlorine component in the exhaust gas is neutralized by contact with water adjusted to be alkaline. At the time of such alkali contact, the exhaust gas is further cooled by sprayed water or the like, and finally cooled to around 60 ° C. In particular, in this embodiment, neutralized water (or water exhibiting alkalinity) is recirculated and used as water for spraying on exhaust gas, thereby greatly reducing the final drainage amount. It is a waste plastic treatment device that does not release industrial wastewater.

  The above is the treatment of pyrolysis gas when the concentration of hydrogen chloride or chlorine compound in the unsuitable gas (pyrolysis gas) measured by the hydrogen chloride measurement device in exhaust gas used as a hydrogen chloride measurement device exceeds a predetermined value That is, desalting. Speaking of the temperature of the pyrolysis portion or pyrolysis gas, it is a treatment of pyrolysis gas generated by pyrolysis near about 300 ° C. (at least less than 350 ° C.), that is, desalting treatment. And the temperature in the pyrolysis kettles 10A, 10B (or the temperature of the pyrolysis gas generated) is less than about 350 ° C., and in the measurement result of the hydrogen chloride measuring device, the pyrolysis gas is not mixed with hydrogen chloride or any If it becomes below the predetermined reference value set in the above, this time, the desalting valves 11A and 11B are closed, the oiling valves 12A and 12B are opened, and the pyrolysis gas is made into a waste plastic oil generation system (oil condensing processing section). Lead to. The pyrolysis kettles 10A and 10B are heated to a second temperature of 350 ° C. or higher, preferably about 400 ° C. to 500 ° C.

  Pyrolysis gas generated by thermal decomposition at about 350 ° C. or higher is first guided to the heavy oil condensers 20A and 20B. In the heavy oil condensers 20A and 20B, the heavy oil component gas in the pyrolysis gas is condensed and recovered by cooling the pyrolysis gas generated by the thermal decomposition at about 350 ° C. or more to about 150 ° C. The This heavy oil component is generated in two systems (system A and system B), and these are sent to the heavy oil tank 21 by a heavy oil feed pump. The heavy oil stored in the heavy oil tank 21 can then be shipped as a product. This is possible because the amount of chlorine components contained in the recovered heavy oil is extremely small.

  The pyrolysis gas (light oil gas) discharged from the heavy oil condensers 20A and 20B is then led to the light oil condensers 30A and 30B. In the light oil condensers 30A and 30B, the light oil gas of about 150 ° C. discharged from the heavy oil condensers 20A and 20B is cooled to about 40 ° C. or less, so that the light oil gas is condensed from the light oil gas. And recovered. This light oil component is also generated in two systems (system A and system B), and these are collected in the light oil tank 90 by the light oil feed pump. The light oil tank 90 is filled with nitrogen gas to prevent accidents. The light oil collected in the light oil tank 90 is used as fuel for the burner that heats the pyrolysis kettles 10A and 10B. In particular, in this light oil, since the mixing amount of chlorine components such as chlorine compounds is extremely small, corrosion of equipment can be suppressed. In this regard, hydrogen chloride and chlorine compounds are mixed in the pyrolysis gas generated by thermal decomposition at less than about 350 ° C., so this is not used as fuel and must be incinerated as described above. Yes.

  Through the above-described treatment, it is possible to remove chlorine from waste plastic resources in which vinyl chloride and other chlorine-containing plastics may be mixed, and to collect hydrocarbon oil in which the amount of chlorine components mixed is extremely small.

  Next, the heavy oil condensers 20A and 20B and the light oil condensers 30A and 30B used in the present embodiment will be described with reference to FIG.

  The oil condenser used in the present embodiment includes a heat exchange tube (tube heat exchanger 1) to which cooling water is supplied, and hydrocarbon oil produced by each oil condenser in pyrolysis gas. And a spraying device (shell type heat exchanger 2) for spraying. By using the tube-type heat exchanger 1 and the shell-type heat exchanger 2, the production efficiency (that is, the condensation efficiency) of hydrocarbon oil (heavy oil and light oil) can be greatly improved, and the size of the apparatus can be reduced. It has become possible to achieve.

  For example, in the heavy oil condensers 20A and 20B, pyrolysis gas of about 400 ° C. is guided, but the heavy oil recovered in the heavy oil condensers 20A and 20B is about 150 ° C. It is. Therefore, the recovered heavy oil or the heavy oil stored at a temperature of about 60 ° C. is guided and sprayed onto the pyrolysis gas (about 400 ° C.). As a result, the pyrolysis gas is significantly cooled. Furthermore, the pyrolysis gas can be efficiently cooled to about 150 ° C. by contacting the inside with a tube heat exchanger in which cooling water circulates. By forming in this way, it is possible to make the equipment itself small.

  In this heavy oil condenser, a temperature control device 3 (that is, a temperature adjusting device) for maintaining the heavy oil at a constant temperature is provided in a region where the condensed heavy oil exists. Is desirable. By providing such a temperature control device 3, the quality of the oil recovered by the heavy oil condenser can be maintained, and mixing of low-boiling components can be avoided. Moreover, the quality of the components in the light oil gas discharged from the first condenser can be kept constant. In the present embodiment, the temperature control device 3 is embodied as a tube heat exchanger in which a heater and cooling water circulate.

  In addition, the waste plastic processing apparatus and processing method concerning this invention are not limited to above-described embodiment, Of course, various changes can be added within the range which does not deviate from the summary of this invention.

1 is a schematic diagram showing an overall configuration of a waste plastic processing apparatus. It is the schematic which shows the structure of a 1st and 2nd oil condenser, (A) is a schematic diagram which shows the whole structure, (B) is a schematic diagram which shows a cooling part.

Explanation of symbols

10 Pyrolysis pot
11 Desalination valve
12 Oil making valve
20 Heavy oil condenser
21 Heavy oil tank
30 Light oil condenser
40 flare stack
50 Combustion furnace
60 Cooling tower
70 Absorption tower
90 Light oil tank

Claims (9)

A heat decomposing unit that heats and decomposes the waste plastic resource to be treated, and a dechlorination unit and an oil condensing unit that process the pyrolysis gas discharged from the heat decomposing unit. A waste plastic processing device that thermally decomposes waste plastic resources that may contain vinyl chloride and other chlorine-containing plastics,
In the guide path of the pyrolysis gas discharged from the pyrolysis section, a hydrogen chloride measuring device that detects the concentration of hydrogen chloride or a chlorine compound in the pyrolysis gas, and the pyrolysis gas discharged from the pyrolysis section A waste plastic processing apparatus, characterized in that a pyrolysis gas switching means for switching a guiding direction to a dechlorination processing unit or an oil condensation processing unit is provided.
A heat decomposing unit that heats and decomposes the waste plastic resource to be treated, and a dechlorination unit and an oil condensing unit that process the pyrolysis gas discharged from the heat decomposing unit. A waste plastic processing device that thermally decomposes waste plastic resources that may contain vinyl chloride and other chlorine-containing plastics,
The thermal decomposition unit includes a temperature adjustment means for adjusting a temperature for thermally decomposing the waste plastic resource to a first temperature and a second temperature higher than the first temperature,
A hydrogen chloride measuring device that detects the concentration of hydrogen chloride or a chlorine compound in the pyrolysis gas is provided in the guide path of the pyrolysis gas discharged from the pyrolysis section,
The temperature adjusting means performs switching between the first temperature and the second temperature based on the measurement result of the hydrogen chloride measuring device,
In the pyrolysis gas guide path, the pyrolysis gas generated at the first temperature is guided to the dechlorination processing section, and the pyrolysis gas generated at the second temperature is guided to the oil condensation processing section. A waste plastic processing apparatus, characterized in that a gas switching means is provided.
The pyrolysis gas switching means is a valve installed in at least one of a path from the thermal decomposition section to the dechlorination section and a path from the thermal decomposition section to the oil condensation processing section,
Furthermore, the temperature detection means which detects the temperature for controlling opening and closing of the said pyrolysis gas switching means is provided in the exhaust-gas vicinity of the pyrolysis gas discharged | emitted from the said thermal decomposition part. Waste plastic processing equipment.
4. The hydrogen chloride measuring device according to claim 1, wherein the hydrogen chloride measuring device is provided in a guide path that guides the pyrolysis gas to a dechlorination processing section that processes the pyrolysis gas, or a guide path of the pyrolysis gas in the dechlorination processing section. The waste plastic processing apparatus according to one item.
The dechlorination processing unit neutralizes the combustion furnace that burns the pyrolysis gas discharged from the thermal decomposition unit, the cooling device that cools the exhaust gas discharged from the combustion furnace, and the exhaust gas that has passed through the cooling device The waste plastic processing apparatus as described in any one of Claims 1-4 comprised including an absorber.
The oil condensing unit is configured to cool the pyrolysis gas discharged from the heat decomposition unit and recover heavy oil, and the pyrolysis gas discharged through the heavy oil recovery device. A second oil condenser that cools and recovers light oil, and a flare stack that incinerates the uncondensed gas that has passed through the light oil recovery device,
Furthermore, the waste plastic processing apparatus as described in any one of Claims 1-5 provided with the fuel supply line which guides the light oil collect | recovered with the 2nd oil condenser to the said thermal decomposition part.
The said 1st and 2nd oil condenser is equipped with the heat exchange tube by which cooling water is supplied inside, and the spray apparatus which sprays the reproduction | regeneration oil produced | generated by each oil condenser in pyrolysis gas. The waste plastic processing apparatus of 6.
The waste plastic processing apparatus according to claim 6 or 7, wherein the first oil condenser includes a temperature control device that keeps the temperature of the oil recovered in the condenser constant.
A waste plastic treatment method for recovering recycled oil from waste plastic resources that may contain vinyl chloride and other chlorine-containing plastics,
Waste plastic resources are pyrolyzed at a first temperature, pyrolysis gas generated by the pyrolysis at the first temperature is incinerated, exhaust gas generated after incineration is cooled, and hydrogen chloride contained therein A desalting treatment step for neutralizing or adsorption treatment,
Measure the concentration of hydrogen chloride or chlorine compound in the pyrolysis gas generated by pyrolysis, and after the concentration of hydrogen chloride or chlorine compound in the pyrolysis gas falls below the standard value, Thermal decomposition at a second temperature higher than the temperature, the pyrolysis gas generated by the thermal decomposition is cooled in one stage or two or more stages to recover the regenerated oil, and the pyrolysis gas after recovering the regenerated oil is incinerated A method for treating waste plastics.

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