JP2707000B2 - Method and apparatus for analyzing mixed amount of polyvinyl chloride resin in mixed plastic waste - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for simply analyzing the amount of a polyvinyl chloride resin mixed in plastic waste.

2. Description of the Related Art As is well known, in recent years, four types of thermoplastic plastic production in Japan have been ranked at 23.0% for polyethylene, 17.0% for polyvinyl chloride resin, 14.4% for polypropylene, and 11.5% for polystyrene. These account for about 66.0% of total plastic production.

On the other hand, plastics discarded after use are collected and discharged in large quantities as mixed plastic waste.
The amount of waste is increasing year by year. Currently, plastic waste treatment methods include landfill, reprocessing,
Incineration and thermal decomposition. In this case, it is difficult to secure a place for the landfill and the land becomes unstable because it does not rot. In the case of the second rework, since only a high-quality part of the plastic waste is used, there are disadvantages that the recycling rate and the use of the recycled product are limited and the durability is short.

Compared with these physical treatment methods, the latter two methods are different in that they mean the destruction and disappearance of plastic bodies.However, in the case of incineration, in general, the incinerator is damaged by high combustion heat. In addition, the structure of the incineration grate itself or the melting thereof blocks oxygen, resulting in incomplete combustion, resulting in a large amount of black smoke and thus causing air pollution. Also,
In the case of thermal decomposition, it has applications that can be used as it is by recycling resources such as gasification and oiling. Especially in the case of oiling, thermal decomposition at low temperature is possible, and storage and transportation are easy. It is. However, the oil product resulting from the thermal decomposition of the mixed plastic waste has a problem that it becomes waxy at room temperature and emits an offensive odor, and carbon is generated to hinder the thermal decomposition.

In addition, when vinyl chloride-based resin, which accounts for the second largest production volume, is mixed in the mixed plastic waste, HCl is generated by incineration or thermal decomposition. There are problems such as rapid progress of aging and further difficulty in measures for preventing air pollution, and it is impossible to completely separate even if the vinyl chloride resin is excluded from these treatments.

Therefore, focusing on the currently common method of analyzing HCl,
Solution measurement methods include the ion electrode method, silver nitrate titration method and mercury (II) thiocyanate absorption spectrophotometry.
As a method of measuring HCl, there is a method of knowing an approximate value of the HCl concentration from the length of the colored layer generated by passing a gas through a detection tube.

However, these HCl analysis methods generally use gas in exhaust gas discharged from exhaust stacks due to incineration and chemical reactions.
In addition to analyzing HCl, it is necessary to prepare a solution whose concentration is estimated in advance, to set up a calibration curve, and to ensure the maintenance of the sensor. Careful attention must be paid to the disposal of materials and the safety of the experimenter.

Therefore, in order to measure the HCl concentration in plastic efficiently and relatively accurately, first, a gas product is obtained from a plastic mixed waste containing a polyvinyl chloride resin, and then a gas product is obtained. There is a need for a method for performing stable and accurate measurement without the above-mentioned problems such as measurement preparation and pretreatment.

Accordingly, an object of the present invention is to provide a measuring method and a measuring apparatus capable of knowing the mixing amount of a polyvinyl chloride-based resin by thermally decomposing a mixed plastic waste and measuring the HCl concentration in a generated gas component by a simple method. It is intended to provide. In other words, by knowing the HCl concentration by pyrolyzing mixed plastic waste, effective use of resources such as reprocessing, incineration and gasification by thermal decomposition, and oilification by thermal decomposition under the premise of preventing pollution. It provides a basic guide to the efficient implementation of

Means for Solving the Problems The first method of the present invention is to provide a sample obtained by pulverizing mixed plastic waste at an isothermal temperature of 360 ° C. in an inert gas or vacuum or at an elevated temperature up to 360 ° C. It decomposes into gaseous products and residues by thermal decomposition, and measures the HCl concentration in the gaseous products.

In the second method of the present invention, the above-mentioned pyrolysis residue is deoxygenated, and then pyrolyzed at an isothermal temperature of 550 ° C. or at a temperature rise from 360 ° C. to 550 ° C. to obtain a further gas product, oil The HCl concentration in the residue according to the first method is measured by separating into a product and a residue and measuring the HCl concentration in the gas product.

Furthermore, in order to measure different amounts of polyvinyl chloride (PVC: the same applies hereinafter) in the mixed plastic waste, the pretreatment method was set in the same manner as in the first method.
A method for pyrolysis at isothermal temperature of 0 ° C or at an elevated temperature from normal temperature to 550 ° C to separate gas products, oil products, and residues, and to measure the HCl concentration in the gas products is configured. You.

Further, the above oil product is again isothermally at 550 ° C, or 550 ° C.
Thermal decomposition at an elevated temperature up to ° C. separates into gaseous products, oil products, and residues, and by measuring the HCl concentration of the gaseous products, the amount of HCl dissolved in the oil products can be determined. The concentration can be measured.

The present invention also provides an apparatus for performing the above four methods: a) Isothermal pyrolysis of a sample in a range from room temperature to 550 ° C.
Or a pyrolysis reactor having a reaction chamber for performing constant-velocity, intermittent temperature-rise pyrolysis; and b) a liquid receiving tank for collecting oil products separated and discharged from the reaction chamber of the pyrolysis reactor. C) a gas pack for collecting gas products separated and discharged from the reaction chamber of the pyrolysis reactor; and d) gas sampling means for introducing, collecting and measuring the gas products from the gas pack. E) HCl in the gas by passing through the metered gas product
A column for separating the components; f) a detecting means for measuring the HCl component separated and discharged from the column; and g) an HCl adsorber for adsorbing the HCl after the measurement. This is a device for measuring the amount of polyvinyl chloride resin mixed in the mixed plastic waste.

Function In the four methods of the present invention described in the preceding paragraph, "pyrolysis at isothermal temperature" and "pyrolysis at elevated temperature" refer to "isothermal pyrolysis" and "isothermal pyrolysis" described in the description of the apparatus configuration a).・ Intermittent temperature rise thermal decomposition ”. This is consistent with the fact that "isothermal pyrolysis" and "isothermal / intermittent temperature rising pyrolysis" are specified in claims 1 to 4 relating to the four methods.

Next, "isothermal pyrolysis" means performing a pyrolysis treatment at a fixed pyrolysis temperature for a fixed time. As a typical case, the particle size is about 10 mm or less as described below, preferably 3.0 mm.
In the case of the following pulverized sample, even if a cylindrical reactor containing the same, for example, a cylindrical reactor having an inner diameter of several 10 mm or less suddenly (assuming) reaches its constant temperature, it usually takes about 30 to 60 minutes, It is considered that the physicochemical effect by the temperature sufficiently extends to the center of the sample granules. Therefore, the certain time here also means a time length of that extent, and also coincides with the time of an experimental example described later.

Further, "constant speed / intermittent temperature rising thermal decomposition" means that the process of raising the temperature at a constant speed is carried out intermittently or at least without interruption within a certain period of time. That is,
Also in the latter embodiment, there is a "continuation" in which the temperature rise is continued from the "off" state in which the starting temperature is stopped for a short time, and a "off" state in which the final temperature is stopped in a short time. It can be said to be one mode of intermittent heating, and "constant speed / intermittent heating" represented by a heating operation in that sense
In the preceding paragraph, "360 ° C
Or "Thermal decomposition at a temperature rise from 360 ° C to 550 ° C".

Even in such a constant-speed / intermittent heating pyrolysis, especially in the pulverized sample targeted by the present invention, heat transfer from the surface to the center does not take much time, and thus the heating rate, and therefore, The length of time required to reach the target temperature has little effect on the degree of thermal decomposition, and the degree is substantially determined by the target temperature to be raised.
In order to reach the target temperature, there must be a state where the temperature is maintained for a very short time, and the sample residue is small even for the end of thermal decomposition such as complete sampling of the sample vapor. Both should be maintained at that target temperature for a few minutes. Therefore, the constant speed / intermittent heating operation includes such a final temperature maintaining time. The definition of terms has been completed above, and then the essential operation of the present invention will be described.

In the thermal decomposition of the mixed plastic waste in the above configuration, when the vinyl chloride resin is heated in an inert gas atmosphere, weight loss occurs due to the release of HCl in a relatively low temperature region of about 240 to 360 ° C., and further heating is performed to about 400 It utilizes the well-known phenomenon that the weight loss due to the C—C bond cleavage occurs at 550550 ° C. to generate various lower hydrocarbons and their derivatives.

In addition, HCl separated and discharged from the column in the measurement system
As a means for detecting the components, for example, a thermal conductivity detector is used.

The present invention is applied to mixed plastic waste in municipal garbage and industrial waste, and measures the mixing ratio of polyvinyl chloride resin in a simple processing method, thereby providing appropriate information for the processing measures. To provide.

The plastic waste applied to the present invention may be any mixture as long as it is a mixture, but is preferably a copolymer or the like. The mixed plastic waste is used irrespective of the shape of a sheet, a film, a molded product, or the like as long as it can obtain about 10 g of a material pulverized to a particle size of about 10 mm or less, preferably 3.0 mm or less.

To explain the function of the invention in relation to the treatment countermeasure information, first, about 10 g of mixed plastic waste is pulverized and charged into a reactor to deoxygenate, and then at a constant speed of 360 ° C or lower at a relatively low temperature. According to the operation of intermittent thermal decomposition or isothermal pyrolysis, the polyvinyl chloride resin is thermally decomposed and mainly HCl is released. Other general-purpose plastics such as polyethylene, polypropylene, polystyrene, etc.
There is a difference in thermal characteristics that the material does not decompose or vaporize unless the temperature is 370 ° C. or higher. Even when these different types of plastics are mixed, the thermal characteristics are not combined and the original characteristics are maintained. For this reason, thermal decomposition at 360 ° C. or lower results in only dehydrochlorination of the polyvinyl chloride resin, and a purity of 99.96% or more is obtained, which can be sufficiently utilized.

In addition, the residue in the reactor is further decomposed from 360 ° C to 550 ° C at an isothermal and intermittent heating pyrolysis or at 550 ° C,
Separates into additional gaseous products, oil products, and residues. Measuring the HCl concentration in this additional gaseous product confirms the HCl remaining in the residue, and from the yield and properties of the oil product, helps in quality assessment for reuse as a resource and pollution prevention Knowledge can be obtained.

As described above, the present invention provides a basic method for determining the mixing ratio of a polyvinyl chloride resin by pyrolyzing a mixed plastic waste in two stages and measuring the HCl concentration of the gas product. A series of measuring methods and a measuring device are provided.

EXAMPLES Hereinafter, the device of the present invention and the method of the present invention using the device will be described based on the illustrated embodiment.

In FIG. 1, a thermal decomposition reactor (1) comprises a heating furnace (2), a temperature controller (3), a reaction tube (4) supported in the heating furnace (2) and having an upper portion protruding, A sample supply port (5) connected to the upper part of the tube (4), a thermocouple (7) inserted into the reaction tube (4), a receiving tank (8) juxtaposed with the reaction tube (4), a cock (9), (9 ') and a gas pack (10).

In the thermal decomposition reactor (1), the particle size is preferably set at 3.3 from the sample supply port (5) connected to the upper part of the reaction tube (4).
Approximately 10.0 g of mixed plastic waste sample crushed to 0 mm or less
Is charged and accommodated in the area of the pyrolysis reaction section (4a) at the bottom of the reaction tube (4). The sample in the reaction section (4a) is a temperature controller (3) connected to the electric circuit of the heating furnace (2).
From room temperature to maximum 550 ℃ at constant speed, intermittent heating or maximum 550 ℃
It is heated isothermally at a suitable temperature up to and pyrolyzed. The vapor generated by this treatment is converted into a pyrolysis reaction tube (4).
Through the outlet (6) at the top of the tank to the liquid receiving tank (8). The liquid purified product condensed during this movement is transferred to the receiving tank (8).
The purified gas which is not condensed here is collected in the gas pack (10) through the cock (9). The internal temperature of the reaction tube (4) is measured by a thermocouple (7), and the result is controlled by a temperature controller (3). The gaseous matter collected in the gas pack (10) is supplied to the HCl analyzer (11) by closing the cock (9) on the pack inlet side and opening the cock (9 ') on the outlet side.

The HCl analyzer (11) includes a suction pump (12) connected to an outlet cock (9 ') of the pyrolysis reactor (1),
A gas sampler for measurement (13) with a switching valve, a column (14), a gas inlet (15) for the column (14), and a carrier gas (16) for guiding the carrier gas to the column through the gas inlet (15). It consists of a gas regulator (17), a column thermostat (18), a thermal conductivity detector (19), a recorder (20), and a hydrogen chloride adsorber (21).

In the hydrogen chloride analyzer (11), the flow rate of a carrier gas (16) such as hydrogen gas or helium gas is precisely adjusted by a gas regulator (17). The column (14) is controlled to a constant temperature by a thermostat (18). Here, a sampler (13) is provided by a pump (12).
When the gas product sent to and measured by the gas sampler (13) is injected from the gas inlet (15) by the switching valve of the gas sampler (13), the HCl component separated in the column (14) is converted into a thermal conductivity detector (19). Is detected as a peak corresponding to the amount of HCl on the basis of the carrier gas flow, and is recorded by the recorder (20). The HCl component flowing as a peak or mixed in the carrier gas (16) passes through the thermal conductivity detector (19) and is completely adsorbed in the hydrogen chloride adsorber (21).

Experimental Example Next, a description will be given of an experimental result obtained by using a pyrolysis reaction apparatus (1) for measuring the mixing amount of a vinyl chloride resin in a mixed plastic waste according to the present invention and an HCl analyzer (11). .

Pyrolysis reactor In the pyrolysis reactor (1), the pyrolysis reaction tube (4)
Was made of Pyrex glass, had a structure similar to that shown in the figure, had a height of 150 mm and an inner diameter of 31 mm, and pyrolyzed 10 g of the mixed plastic waste at various thermal decomposition temperatures. To prevent corrosion by HCl, the liquid product receiving tank (8) is also made of Pyrex glass, and its volume is
It was 20 ml. As the gas pack (10) for collecting gaseous matter, a gas pack made of Teflon and having a volume of 5 was used.

Analyzing device The device for analyzing HCl in the collected gas (11) has the same structure as the illustrated embodiment, and the suction pump (12) has a flow rate of 20 ml / m.
In, the gas sampler (13) has a capacity of 0.2 ml to 1.0 ml, and the column (14) has a size of 3 mm ^φ x 5 m, and the filler is silicon G
E SF-96 Greensolve F, these and gas inlet (1
For 5), a Teflon-made one was used to prevent corrosion.
The temperature of the gas inlet (15), thermostat (18), and thermal conductivity detector (19) was maintained at 65 ° C, and hydrogen gas was used as the carrier gas (16) of the HCl analyzer (11). .

Samples used PVC (degree of polymerization 1020, powder) and high-density polyethylene (PE, viscosity average molecular weight 30,000, pellets) were used as samples. In the case of only PVC and the pyrolysis of a mixture of PE and PVC, the sample amount was 10.0 g. The analysis results of the HCl concentration obtained for these samples under various conditions are shown below.

[1] Analysis result of HCl FIG. 2 shows the analysis result of a gas product obtained by thermally decomposing only the sample PVC while increasing the temperature from room temperature to 550 ° C. using the apparatus of the present invention. FIG. 3 shows the analysis results of gas products obtained by thermally decomposing a sample in which several percent of PVC was mixed with PE while increasing the temperature from room temperature to 550 ° C. From the graphs of FIG. 2 and FIG. 3, it can be seen that the analysis value of HCl according to the present invention, particularly the third method, is sharply measured, and the separation from other generated gas components is clear.

[2] Comparison of analyzers Table 1 shows that the analysis of HCl obtained by pyrolyzing only PVC while raising the temperature from room temperature to 550 ° C was performed by the measurement system of the present invention, and through the same process. This figure shows a comparison of analysis results obtained when a thermally decomposed gas is absorbed in water and the water is subjected to an existing silver nitrate titration method.

From Table 1, it was confirmed that the result of the analysis of HCl by the apparatus of the present invention was higher in accuracy than the existing apparatus, and that the analysis time was significantly reduced. Further, when analyzing HCl in a mixed sample, it is clear that a uniform sample can be obtained as a whole because the apparatus of the present invention has a large throughput.

[3] HCl generation rate by thermal decomposition Fig. 4 shows the HCl generation rate in the gas generated by thermally decomposing only PVC at 260 ° C to 570 ° C for 60 minutes at isothermal temperature for about 60 minutes. It shows an analysis result. In this experiment, the time was extended to 60 minutes to confirm the effect of isothermal pyrolysis at different temperatures. Figure 4 shows that HCl from PVC
It is clear that the production rate depends on the pyrolysis temperature,
For example, the HCl generation rate at 350 ° C. of about 0.96 is an indication that the first method (upper limit of 360 ° C.) of the present invention can be used to measure the HCl and determine the PVC resin content sufficiently, or the necessity of a slight correction. In addition, when the thermal decomposition temperature is 500 ℃ or more,
The dehydrochlorination is complete, which means that in the third process of the invention PVC
It was confirmed that the system resin content could be determined almost certainly.

[4] Measurement of HCl melted in oil product A sample obtained by isothermally pyrolyzing a sample obtained by mixing 15 wt% of PVC in dehydrochlorinated PE at 550 ° C and 360 ° C from normal temperature.
Isothermal pyrolysis for 30 minutes in a furnace heated to
The results of measuring the differences in the concentrations of HCl dissolved in the oil products obtained by heating and pyrolyzing to 0 ° C. are as shown in Table 2.

Each oil product in this case is again isothermally pyrolyzed at 550 ° C. to separate further gas products, oil products, and residues,
The gas product was analyzed by a detector tube for HCl (20 to 500 ppm). These treatments, and again the isothermal pyrolysis and analysis, relate to the fourth method of the present invention, which, on the other hand, is a gas which would be obtained only by the treatment of the third method of the present invention. It is also a confirmation of the effectiveness of the measurement of HCl in the product). According to Table 2, 30 at 360 ℃
The oil product obtained by the process of isothermal pyrolysis for 1 minute, followed by pyrolysis at 550 ° C. is
The concentration is low and the oil product is decomposed by pyrolysis again.
HCl proved feasible. In the treatment, the concentration of HCl remaining in the oil product is higher than that of the treatment, but the HC is removed by thermal decomposition again.
l is considered possible.

[5] PVC mixing ratio and HCl generation ratio PVC is mixed with PE in a range of 0.3 wt% to 15.0 wt%, and 360
The mixture was subjected to isothermal pyrolysis at 30 ° C. for 30 minutes, followed by pyrolysis at 550 ° C. This process belongs to a modification of the third method of the present invention. FIG. 5 shows the relationship between the mixing ratio of PE and PVC and the generation ratio of HCl in this case. Fifth
From the figure, it can be seen that even when only 0.3 wt% of PVC is mixed in the mixed plastic, the concentration of HCl generated by thermal decomposition can be accurately analyzed. Furthermore, based on the HCl concentration of 62.5 wt% generated by the thermal decomposition of PVC alone, the HCl concentration ratio generated by the thermal decomposition when the mixing ratio of the mixed plastic was changed was in good agreement. From this result, it was found that by analyzing the generated HCl concentration ratio, the mixing ratio of the PVC-based plastic in the mixed plastic can be estimated.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example in which the amount of polyvinyl chloride resin in a mixed plastic waste is analyzed by the method of the present invention, and FIGS.
And FIG. 4 is a graph showing the results of HCl analysis of a% PVC sample and a sample containing several% PVC in PE. FIG. 4 shows the thermal decomposition temperature of the PVC sample / HCl by the method of the present invention.
FIG. 5 is a graph showing the relationship between the PVC / PE mixing ratio and the HCl generation ratio according to the method of the present invention. (1) Thermal decomposition reaction device (2) Heating furnace (3) Temperature controller (4) Reaction tube (4a) Thermal decomposition reaction section (5) Sample supply port (6) ) Discharge port (7) Thermocouple (8) Liquid receiving tank (9), (9 ') Switching cock (10) Gas pack (11) Hydrogen chloride analyzer (12) ) Suction pump (13) Gas sampler (14) Column (15) Gas inlet (16) Carrier gas (17) Gas regulator (18) Constant temperature bath (19) ) Thermal conductivity detector (20) Recorder (21) Hydrogen chloride adsorber

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Fukuda 17-2-1, Tsukikan-Higashijo, Toyohira-ku, Sapporo-city, Hokkaido Inside the Industrial Technology Research Institute, Hokkaido Industrial Development Laboratory (72) Inventor Hiroyuki Nakaya Shinnoike Nakano, Himeji City, Hyogo Prefecture Town 1-21 (72) Inventor Kenji Kinoshita Judge, 772 Aoji-cho, Kusatsu-shi, Shiga Referee Nobuto Ichikawa Referee Toshio Uchida Referee Tetsuzo Komatsu (56) References JP-A-55-47445 (JP, A) JP-A-54-147891 (JP, A) JP-A-59-112154 (JP, U)

Claims (5)

(57) [Claims] 1. A sample obtained by crushing mixed plastic waste is deoxygenated in an inert gas or in a vacuum,
Isothermal pyrolysis in the range of ~ 360 ° C or from normal temperature to 360 ° C
Isothermal and intermittent heating pyrolysis in the range above to separate into gaseous products and residues, and determine the amount of polyvinyl chloride resin in the sample by measuring the concentration of hydrogen chloride (HCl) in the gaseous products A method for measuring the amount of a polyvinyl chloride resin mixed in a mixed plastic waste. 2. A sample obtained by crushing mixed plastic waste is deoxygenated in an inert gas or in a vacuum,
Isothermal pyrolysis in the range of ~ 360 ° C or from normal temperature to 360 ° C
Isothermal and intermittent temperature rising pyrolysis in the range to separate into gaseous products and residues, deoxygenating the residue in an inert gas or vacuum, or isothermal pyrolysis at 550 ℃, or 360-550
Isothermal and intermittent heating pyrolysis in the range of ℃ to separate into further gas products, oil products and residues, and measure the HCl concentration in the further gas products to measure the mixed plastic waste below 360 ℃ A method for measuring the content of HCl, comprising determining the content of HCl in a residue resulting from the thermal decomposition of water. 3. A sample obtained by grinding the mixed plastic waste is deoxygenated in an inert gas or vacuum,
By isothermal pyrolysis at ℃ or isothermal / intermittent heating pyrolysis in the range of room temperature to 550 ° C to separate gas product, oil product and residue, and by measuring the HCl concentration in the gas product A method for measuring the amount of polyvinyl chloride resin in mixed plastic waste, comprising determining the amount of polyvinyl chloride resin in a sample. 4. A sample obtained by grinding a mixed plastic waste is deoxygenated in an inert gas or vacuum,
Isothermal pyrolysis at ℃ or isothermal / intermittent heating pyrolysis in the range of room temperature to 550 ° C to separate into gas products, oil products and residues, and to remove the oily organisms in an inert gas or vacuum. After oxygenation, it is subjected to isothermal pyrolysis at 550 ° C or isotonic and intermittent heating pyrolysis at a temperature in the range of 360 to 550 ° C to separate into further gas products, oil products and residues, and to produce the above-mentioned further gas. In things
A method for measuring HCl content, comprising determining the content of HCl dissolved in the first pyrolysis oil product by measuring the HCl concentration. 5. A pyrolysis reactor having a reaction chamber for performing isothermal pyrolysis or isothermal / intermittent heating pyrolysis of a sample in a range from room temperature to 550 ° C .; and b) said pyrolysis reactor. A tank for collecting oil products separated and discharged from the reaction chamber of c), and c) a gas pack for collecting gas products separated and discharged from the reaction chamber of the pyrolysis reactor, d) gas sampling means for introducing, collecting and measuring a gas product from the gas pack; e) a column for separating an HCl component in the gas by passing the measured gas product; f) a detecting means for measuring the HCl component separated and discharged from the column; and g) an HCl adsorber for adsorbing the HCl after the measurement. Of vinyl resin mixed amount Constant apparatus.