KR101130337B1 - Method of converting pyrolysis wax oil from municipal waste plastic into high-value light hydrocarbon - Google Patents

Abstract

The present invention relates to a method for converting a low-grade wax oil produced by pyrolysis of a mixed-use waste plastic into pyrolysis in the presence of a zeolite-based catalyst to convert it into a high-grade hydrocarbon.
More specifically, the present invention relates to a process for producing a wax oil by pyrolyzing a wax oil obtained by pyrolyzing a mixed waste plastic of a polyolefin-based main component of a mixed waste plastic in a high-temperature rotary kiln reactor with a zeolite- Quot;

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting wax oil produced by pyrolysis of waste plastics into high-

The present invention relates to a method for converting a low-grade wax oil produced by pyrolysis of a mixed-use waste plastic into pyrolysis in the presence of a zeolite-based catalyst to convert it into a high-grade hydrocarbon.

A large amount of disposable items (plastic, poly-steel, vinyl, styrofoam, etc.) are used along with industrial development. More than 90% of these disposable products are made of plastic or synthetic resin containing oil. While these plastic and synthetic resin products provide ease of use, they are a major cause of serious environmental pollution. Currently, efforts are being made to actively improve environmental problems through various measures. However, in particular, plastic is not recycled more than the amount currently produced in the recycling sector, and there are many difficulties in disposal. . The advantages of plastics have been pointed out as disadvantages and various limitations have been reached for incineration of landfill.

In the case of a single-piece plastic, there is no difficulty in recycling, but in the case of mixed plastic, recycling is difficult. In order to recycle the mixed waste plastic as a single material product, many processes are required, and it is necessary to separate the waste materials according to the high added value of the recycled product.

Gasification and oil paintings have recently attracted attention as a way to recycle EPR (Extended Producer Responsibility) end product, which is a mixed waste plastic, in an environmentally friendly and resource-saving way. Conventionally, there is known an emulsifying apparatus for extracting oil components by chemical treatment and pyrolysis of waste synthetic resin. However, since the maintenance cost and the facility cost are high, the waste plastics can not be treated at a time, The extraction efficiency is only 30 to 40%, which is disadvantageous in terms of economical efficiency. Particularly, there has been a problem that when the pyrolysis is carried out at a high temperature in a vacuum atmosphere in order to melt the waste synthetic resin, there is a risk of explosion and a high temperature is required to be periodically cooled.

Thus, a method of producing a solid fuel by mixing a combustible compounding agent with pyrolytic wax obtained by melting waste plastics at low temperature in the presence of a catalyst, followed by molding and drying is known. In addition, an emulsifying apparatus for melting and refining waste synthetic resin through indirect heat and low-temperature pyrolysis has been studied.

Pyrolysis oil produced by pyrolysis of waste plastics in the living system has recently attracted attention as an alternative fuel. Pyrolysis oil produced mainly from waste plastics made mainly of a polyolefin polymer contains wax as well as light oil and heavy oil. Wax oil has low utility value, low mobility under steam, high molecular weight, and wide distribution of carbon number. In particular, direct use of wax oil in combustion reactions as alternative fuels can cause problems with equipment operation, such as clogging pipelines or shortening the life of the equipment. Since the wax oil generated from the pyrolysis reactor is separated from general pyrolysis oil which can be sold to industry or the like, it is necessary to convert the wax oil into a low-boiling high-grade oil.

Therefore, there is a need for high-value-added low-grade pyrolysis oil containing wax or high-boiling point oil, which accounts for a large portion of the pyrolysis oil, and research has been conducted on the conversion to a high value-added substance using a catalytic process.

The present invention relates to a method for converting a low-grade wax oil having 5 to 40 carbon atoms produced by pyrolysis of a mixed-use waste plastics into pyrolysis in the presence of a zeolite-based catalyst to convert it to a higher hydrocarbon.

More specifically, the present invention relates to a process for producing a wax oil by pyrolyzing wax oil obtained by pyrolyzing a mixed waste plastic of film oil which is a polyolefin-based main component in a high-temperature rotary kiln reaction apparatus, in a zeolite- Quot;

Wax oil obtained by pyrolyzing mixed mixed waste plastic discharged in the form of film in a general household as a reaction raw material in a commercial rotary kiln reactor has a wide distribution ranging from 5 to 40 carbon atoms, and some of the light oil is included. However, the heavy oil component And the oil consists mainly of normal paraffins and normal-olefins, in particular more than 70% of normal paraffins.

The raw pyrolysis wax used in the present invention was a high boiling point wax produced by pyrolysis in a commercial scale rotary kiln type pyrolysis process of Dongfeng RPF Co., More specifically, the thermally cracked wax is composed of 70.7% of n-paraffin, 8% of n-olefin and other components. Properties of pyrolyzed wax oil raw materials are shown in the following table. Pyrolytic wax oil exhibits a high hydrogen content (H / C ratio), a higher calorific value as compared to a common oil, and contains about 0.75% nitrogen.

Examples of the zeolite catalyst used in the present invention include a ZSM-5 catalyst (HZSM-5; pure water), a zeolite Y catalyst (HY; pure water or 20% clay) or a mordenite catalyst (HM: 20% clay or alumina) From which catalysts with or without clay or alumina can be used as supports and they exhibit different properties. The composition and BET surface area for each type of zeolitic catalyst are shown in the following table.

The catalysts were used to decompose the pyrolyzed wax at 450 ° C for 1 hour, and the distribution of the obtained products is shown in the following table.

Different zeolitic catalysts exhibit different product distributions, and in particular the ZSM-5 catalyst represents the highest gas fraction of about 50%, whereas the catalyst containing mordenite is the lowest conversion of heavy oil to light oil, with about 10% Gas fraction. This indicates that the zeolite form plays an important role in converting pyrolyzed wax oil to light oil.

The following table shows the distribution of liquid paraffins (normal / iso), olefins (normal / iso), naphthene and aromatic products obtained after decomposition of pyrolysis wax oil with different zeolitic catalysts.

When ZSM-5 catalysts are used, cyclic components are produced, including naphthenic 18% and 77% aromatic products. Of the zeolitic catalysts, the ZSM-5 catalyst exhibits the highest fraction of aromatic products through the cyclization of paraffins and olefins obtained from pyrolysis of heavy oils. The main products naprene and aromatic products have 5 to 12 carbon atoms as a gasoline range component. More specifically, the aromatic products are mainly the C6, C7 and C8 components of benzene, toluene, xylene and ethylbenzene, and the naphthenic products are the C10, C11 and C12 components of the benzene ring structure. This product is due to the morphological selectivity of the ZSM-5 catalyst.

The zeolite Y catalyst not only represents a high fraction of the high octane number of branched chain light oils, but also represents a high fraction of aromatic products in the gasoline range components.

Catalysts containing mordenite exhibited the lowest conversion of pyrolytic wax oils to light oils and exhibited much more paraffinic products in the liquid product, resulting in similar characteristics of pyrolytic wax oils.

In the present invention, the decomposition effect of the catalyst according to the amount of the catalyst in the gas phase catalytic cracking reaction was confirmed using a ZAM-5 catalyst capable of relatively easily producing an aromatic production oil having a narrow carbon number distribution.

FIG. 1 is a view showing a reaction experimental apparatus of the present invention. The line was heated from the syringe pump to the reactor for smooth injection of the high boiling point sample, and the temperature was confirmed by installing a thermal conductivity meter. In addition, the reaction temperature was checked in real time by a thermometer installed inside the reactor, and the product was collected while maintaining the ice temperature outside the collector in order to collect the product from the reactor in a liquid state. In the experimental method, the pretreated catalyst was put into a reactor, and then a wool was put on the reactor so that the sample coming into the reactor could contact the catalyst uniformly. Then, the reactor was connected to the apparatus, and the temperature of the high-temperature electric furnace was stabilized by raising the temperature to the reaction temperature. Then, the syringe was poured into the syringe pump at a feed rate of 0.3 g / min for 60 minutes.

The liquid product obtained after the experiment was qualitatively and quantitatively analyzed by GC and MASS, and then the characteristics of the liquid product were examined through the carbon number distribution and PONA distribution of each liquid product. The GC used for the analysis was Agilent's 6890N model and Mass 5890 model.

The distribution of various products obtained by gas-phase catalytic cracking of the high boiling point wax is shown in Table 5 as a function of the amount of catalyst. As the content of the catalyst increases, the fraction of the liquid product decreases and the fraction of the gaseous product relatively increases due to the decomposition effect of the catalyst. FIG. 2 shows the GC analysis peak and carbon number distribution of the liquid product obtained by the decomposition experiment according to different catalyst contents. When the catalyst content is small, the product of the gasoline range is generated to a large extent, but the decomposition activity is low, so that the components having 20 or more carbon atoms having a high boiling point are also seen. As the catalyst content gradually increases, the high boiling point component decreases, It can be seen that the components are further increased.

This tendency can be found from the distribution of gasoline, kerosene + diesel oil and heavy oil of FIG. As the catalyst content increases, the fraction of gasoline increases, while the fraction of heavy oil, which is larger than kerosene + diesel, decreases. It can be seen that the decomposition of heavy oil by catalytic decomposition further decomposes into gasoline of low molecular weight. However, the major component of the liquid product was found to be within the range of about 10 carbon atoms within the range of gasoline, regardless of the amount of catalyst.

4 shows changes in the distribution of paraffin, olefin, naphthene and aromatics (for example, paraffins, olefins, naphthenes and aromatic products) in the produced oil depending on the content of the catalyst. From this, it can be seen that as the catalyst content increases, the fraction of the naphthene and aromatic product increases, whereas the fraction of the linear naphtha-paraffin product in the saturated hydrocarbon, paraffin, decreases significantly. This shows that the ZSM-5 catalyst improves the production of an aromatic product having a cyclic structure by pore shape selectivity. This can be seen in the carbon number distribution of the paraffins, olefins, naphthenes and aromatic products of FIG. Although most of the products are obtained in the gasoline range, the aromatics, which are one of the benzene rings with 6 to 9 carbon atoms, are predominantly produced. On the other hand, naphthenic products were mainly produced from 11 to 13 carbon atoms, and paraffin components were mainly obtained by catalytic decomposition.

In the present invention, the decomposition effect of the catalyst according to the reaction temperature in the gas phase catalytic cracking reaction was confirmed by using a ZAM-5 catalyst capable of relatively easily producing an aromatic production oil having a narrow carbon number distribution.

The fraction of products obtained by gas phase catalytic cracking at different half-temperatures on the ZSM-5 catalyst is shown in Table 6. < tb > < TABLE > In the case of 3g, the fraction of liquid product decreases and the fraction of gaseous product increases with increasing reaction temperature. This is similar to the case where the catalyst content is 5 g. In the case of 5 g, the decomposition activity of the catalyst is good and the effect of temperature is not remarkable.

On the other hand, the GC peak and the carbon number distribution of the liquid product obtained by the decomposition reaction at each reaction temperature are shown in Fig. The carbon number of the product obtained at 350 ℃, which is low in reaction temperature, is mainly distributed in the range of 4 to 12, but some 20 or more heavy oil components are also produced. This tendency appears at all the reaction temperatures, but as the reaction temperature increases, the heavy oil component gradually disappears and the components of the gasoline range increase, and the decomposition performance is gradually increasing.

This tendency can also be seen from the result of dividing into gasoline, kerosene + case and heavy oil range for the product oil shown in Fig. As the reaction temperature increases, the change of the fraction value of gasoline + kerosene with intermediate carbon number is not great, but the fraction of heavy oil, which is a large molecule, decreases, and the fraction of gasoline with low molecular weight tends to increase remarkably. The PONA distribution, which is the characteristic of the liquid product with increasing reaction temperature, is shown in Fig. As the reaction temperature increases, the fraction of the naphthenic component, which is a cyclic structure, does not change but the fraction of aromatic product, which is the main product, tends to increase. Conversely, n - paraffin in the paraffin product tends to decrease more rapidly than the iso - paraffin as the reaction temperature increases. These results show that the reaction mechanism changes with increasing reaction temperature on ZSM-5 catalyst. The olefin component in the product produced a very small amount at all reaction temperature ranges. These results are shown in FIG. 9, and are shown in the carbon number distributions of paraffins, olefins, naphthenes and aromatic products obtained at the respective reaction temperatures. The aromatic product, which is the main product in the product, has 6 to 9 carbon atoms. Next, many naphthenes have 10 to 13 carbon atoms. Paraffin is a very small number of carbon - It was composed of oil. In this case, the product having a large number of carbon atoms is generated when the reaction temperature is low.

Catalytic cracking of pyrolyzed wax oil using zeolite catalysts, especially ZSM-5 catalyst, has resulted in the production of aromatic products in low boiling point oil and liquid forming oil in the gasoline range, thus achieving a high quality of high boiling point wax oil. It is possible to convert pyrolytic wax oil recycled from waste plastic into high value-added light oil, so that it is possible to obtain an alternative fuel as well as to prevent environmental pollution.

1 is a diagram of a reaction experimental apparatus.
Figure 2 shows the effect of the amount of catalyst on the GC peak and carbon number distribution of the produced oil.
Figure 3 shows the produced oil gasoline, kerosene + diesel and heavy oil range fractions as a function of the amount of catalyst.
Figure 4 shows the resulting paraffin, olefin, naphthene and aromatics distribution as a function of catalyst volume.
Figure 5 shows the effect of the amount of catalyst on the carbon number distribution of paraffin, olefin, naphthene and aromatic components of the produced oil.
Figure 6 shows the effect of reaction temperature on GC peak and carbon number distribution of produced oil.
Figure 7 shows the resulting crude gasoline, kerosene + diesel and heavy oil range fractions as a function of reaction temperature.
Figure 8 shows the resulting paraffin, olefin, naphthene and aromatics distribution as a function of reaction temperature.
Figure 9 shows the effect of reaction temperature on the carbon number distribution of paraffin, olefin, naphthene and aromatic components in the product oil.

Hereinafter, the present invention will be described in detail with reference to the following examples.

Control Example 1

Pyrolysis of pyrolysis wax

Pyrolysis wax as a raw material was injected at an injection rate of 0.3 g / min and reacted at a reaction temperature of 450 캜 for 1 hour to perform pyrolysis. The resulting product oil had a carbon number distribution of 5 to 40 and showed a similar carbon number distribution to that of the raw wax, and the oil had a characteristic of normal-paraffin of 70% or more.

Example 1

Catalytic cracking of pyrolysis wax - Mordenite catalyst

5 g of mordenite catalyst was used in the zeolite catalysts under the same experimental conditions (injection rate 0.3 g / min, reaction temperature 450 ° C., reaction time 1 hour) as in the above control example.

The resulting product oil was a heavy oil having a high fraction of not less than 50% of the components having 21 or more carbon atoms. Further, the product oil obtained from the obtained product was about 60% of normal paraffins, about 10% of n-olefins, About 3% of tungsten and about 9% of aromatics mainly composed of BTX (benzene, toluene, xylene) were contained. This shows that aromatic products and iso-olefins, which are high-value-added products, are produced more than the pyrolysis.

Example 2

Catalytic cracking of pyrolysis wax - Zeolite Y

Zeolite Y was used as a catalyst under the same experimental conditions as above.

The product oil obtained by catalytic cracking by zeolite Y contained about 80% of the product oil in the range of gasoline having up to 10 carbon atoms and the remainder including the product oil having 11 to 20 carbon atoms. More specifically, the properties of the resulting oil obtained are about 12% for normal paraffin, about 6% for normal olefins, about 25-30% for iso-paraffins, about 10% for iso-olefins, about 10% It was found that about 30% of the aromatics mainly composed of BTX were contained. In particular, decomposition by zeolite Y catalyst resulted in about 30% of BTX-based aromatic products, which is higher than with mordenite catalysts. In addition, iso - paraffin, which is a high octane value, showed a high value of about 30%.

Example 3

Catalytic cracking of pyrolytic wax - ZSM-5

ZSM-5 catalyst was used as a catalyst under the same experimental conditions as above.

The product oils obtained by catalytic cracking with ZSM-5 catalysts contained product oils having a product yield of 5 to 10 carbon atoms in the high value-added gasoline range of 85% or more, and the remainder being 11 to 20 carbon atoms. Furthermore, the characteristics of the produced oil are about 20% of naphthene and about 20% of BTX (benzene, toluene, xylene), naphthene and naphthene which are mostly cyclic structure, about 3% of normal paraffin and about 1% Containing more than 75% of aromatic products as the main component. ZSM-5 catalyst among the zeolite catalysts catalyzed the wax obtained by pyrolyzing the mixed waste plastics, and it was found that aromatic production oil was generated most. In particular, most of the BTX product was produced in the aromatic product, totaling 65%, which is about 15% benzene, about 30% toluene, about 20% xylene.

Example  4

Catalytic cracking of pyrolytic wax - ZSM-5

Experiments were carried out using ZSM-5 catalyst, which is a zeolite catalyst as in Example 3, under the same experimental conditions as the experimental conditions except that the reaction temperature was 350 ° C. and the catalyst amount was 3 g. The results obtained show that the aromatics produced in the paraffins, olefins, naphthenes and aromatics were the most abundant in the production of aromatics, while the fractions of aromatics were 53%, lower than the reaction temperature of 450 ℃ and the catalytic amount of 5g. A total of 43% of BTX was obtained with about 6% of benzene, about 20% of toluene, and about 17% of xylene. This shows that the BTX component in the oil is almost 50% even in the gentle experimental conditions, and the reaction temperature is high and the amount of the aromatic BTX in the product oil is increased when the amount of the catalyst is increased as in Example 3. [

ZSM-5 catalyst among the zeolite catalysts catalyzed the wax obtained by pyrolyzing the mixed waste plastics, and aromatic production oil was produced the most.

The following Tables 7, 8 and 9 show the distribution of the products obtained in the gas phase decomposition reaction using the ZSM-5 catalyst according to the catalyst amount and the reaction temperature.

In addition, the zeolite-containing catalyst, in particular ZSM-5 catalyst under the pyrolysis is a reaction temperature of 350 to implant conditions at 450 ℃ LHSV (Liquid Hourly Space Velocity , h -1) of 3 to 10:

(LHSV) = injection rate / amount of catalyst = 0.3 g / min / 2 g-5 g amount of catalyst x 60

1. Syringe pump
2. Heating Line
3. Three-way valve
4. Furnace
5. Reactor
6. Temperature regulator
7. Temperature Indicator
8. Receptor
9. Condenser
10. Shift jack
11. On / off valve
12. N ₂ cylinder

Claims (5)

a) filling a particulate ZSM-5 catalyst or zeolite Y catalyst into a reactor;
b) injecting a low grade wax oil into the reactor filled with the catalyst;
c) pyrolysis in an atmosphere of nitrogen at an LHSV of from 3 to 10 h < ^-1 > at 350 to 450 DEG C,
Wherein the pyrolysis step product is an aromatic product having one benzene ring of (C6-C9) in an amount of 50 to 80% of the total product fraction.
The method according to claim 1,
Wherein the lower wax oil comprises normal paraffin and normal olefin.
The method according to claim 1,
Wherein the ZSM-5 catalyst or the zeolite Y catalyst has a BET surface area of 400 to 800 m 2 / g.
The method according to claim 1,
Wherein the pyrolysis step product comprises an aliphatic product of (C5-C12), (C6-C8) aromatic product and (C9-C12) naphthene product.
The method according to claim 1,
The pyrolysis step product may be selected from the group consisting of benzene, toluene, ethyl-benzene, 1,3-dimethyl-benzene, p-xylene, Methyl-benzene, 1,2,3-trimethyl-benzene, and 2,3-dihydroindene.

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