KR100381563B1 - Process for preparing catalysts for liquid-phase degradation of waste polymer, and catalytic degradation process using the same - Google Patents

Abstract

In the present invention, 3 to 16 (K ₂ O · Na ₂ O) · 0.25 to 1.0Al ₂ O ₃ · 50 to 100SiO ₂ · 2150 to 3000H without organic template material for use as catalyst in liquid phase catalytic decomposition of waste polymer materials 0.5-4 g per kg of synthetic mother liquor was added to the synthetic mother liquor of ₂ O composition as a core and synthesized at 175-205 ° C. for 1 to 3 days, followed by acid treatment with 0.2-3N aqueous hydrochloric acid solution; Treatment with 0.2-4N aqueous metal hydroxide solution followed by acid treatment; Provided are a method for preparing a hydrogen ion-exchanged MFI zeolite catalyst, and a method for converting waste polymer materials into low molecular hydrocarbons characterized by liquid phase catalytic decomposition.

Description

Method for preparing catalyst for liquid phase decomposition of waste polymer material and method for decomposition using same {PROCESS FOR PREPARING CATALYSTS FOR LIQUID-PHASE DEGRADATION OF WASTE POLYMER, AND CATALYTIC DEGRADATION PROCESS USING THE SAME}

The present invention relates to a method for preparing a catalyst for the liquid phase decomposition of waste polymer materials and to a liquid phase decomposition process using the same. More specifically, the present invention provides a method for preparing a catalyst for decomposing polyolefin-based waste polymer materials and converting them into low-molecular hydrocarbons that can be used as raw materials for liquid fuel or petrochemical industry, and decomposing waste polymer materials into low-molecular hydrocarbons using such catalysts. To provide a way.

As the types of polymer materials are diversified and their applications are widespread, the amount of polymer materials used is rapidly increasing. On the other hand, many polymer materials are discarded because they are cheap and have low durability and short lifespan. In 1998, the production of high molecular materials in our country amounted to 7.5 million tons, and the amount of waste polymers generated was very high, reaching 3 million tons. About 16% of the discarded polymer is used to manufacture recycled containers or pipes through physical recycling, but most of the waste polymer is discarded as it is not properly recycled. The method of incineration to recover heat is also very efficient in terms of energy, but harmful gases such as dioxins are generated during incineration. Landfilling of waste polymers not only causes soil pollution, but it is also difficult to secure adequate landfill due to the aversion atmosphere. As the generation of waste polymer material increases rapidly, there is no proper recycling method or disposal method, which makes disposal of waste polymer material a serious social problem.

Since most high molecular materials are made of carbon and hydrogen, the most practical method is to decompose them into low molecular hydrocarbons and recycle them as raw materials for fuel or petrochemical industry. The pyrolysis process that decomposes a polymer material at high temperature by applying heat is simple and easy to operate, but requires a large amount of energy and has a low carbon quality due to the wide carbon number distribution of the produced liquid fuel. The use of catalysts is advantageous in that the decomposition temperature can be lowered and the carbon number distribution of the product can be controlled, but the profitability is lowered due to the catalyst cost. The gas phase catalytic cracking process that reacts vaporized polymer material with a catalyst through primary pyrolysis can be operated stably, but the profitability is low due to the high energy and catalyst costs. On the other hand, the liquid catalyst decomposition process of decomposing by adding a catalyst to the molten waste polymer material is very preferable because a large amount of liquid product can be obtained at a low temperature. However, the catalyst is rapidly deactivated by carbon deposition by a polymer material, so that the catalyst is used only once. The cost of the catalyst is high. Therefore, in the liquid catalyst decomposition process, the catalyst cost is an important factor that determines the profitability of the decomposition process of waste polymer materials.

The catalyst used in the liquid catalyst decomposition process of the waste polymer material should have high activity so as to decompose the polymer material even at low temperature, and control the decomposition degree so that a lot of liquid product is produced. In particular, economic activity can be secured only when the deterioration of activity due to carbon deposition is slow so that a large amount of waste polymer material can be treated with a small amount of catalyst. If the acid strength is high, the decomposition activity of the polymer is high, but the carbon deposition is severe. Therefore, when the acidity is strong and the pore structure and the acid concentration are appropriate, the formation of high-boiling compounds is suppressed, so that the degradation of activity due to carbon deposition is slow, which is likely to be a catalyst. In addition, it is more effective if the outer surface area is large and the possibility of contact with the polymer material is high. As such, the catalyst that can be used in the liquid catalytic cracking process is complex and not required, and can be used only once, so the catalyst price must be very cheap. Therefore, the catalyst for the liquid phase catalytic cracking process has to be prepared inexpensively while satisfying all of the complex properties, and thus, an appropriate manufacturing method has not been devised.

Many zeolite catalysts have been studied as catalysts for the decomposition of waste polymer materials (1). In the pores of bent zeolite MFI or BEA zeolite, long hydrocarbons are less likely to be produced or diffused. As a result, the formation of long hydrocarbons, which are carbon deposition precursors, is inhibited, resulting in slow catalyst deactivation due to carbon deposition. The smaller the particles, the larger the outer surface area, the shorter the diffusion distance within the particles, and the greater the possibility of contact with the polymer material, resulting in higher decomposition activity. In fact, small particles of MFI and BEA zeolite catalysts rapidly decompose high molecular materials such as polyethylene (PE) wax and high density polyethylene (HDPE). However, even larger zeolites of the same structure have a significantly lower decomposition activity (2). Because of the large size of the molecules, the diffusion of the polymer material in the zeolite pores is slow, so that the decomposition reaction of the polymer material is faster in the outer surface than in the pores. However, since there is no restriction | limiting of a pore structure on an outer surface, the degradation of activity by carbon deposition advances rapidly. In particular, if the concentration of the acidic acid on the outer surface is too high, carbon deposition may be severe and the activity itself may be lost by covering the carbon to the pore inlet. Taken together, these catalysts, which can be used for liquid phase catalytic decomposition, have a small particle and have a large external surface area, which is excellent in activity, but do not have too many strong acid points, and thus, carbon deposition rate is desirable (3).

The present invention is a process for liquid-phase decomposition of waste polymer materials containing low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) such as polyolefin-based waste polymer materials composed of a single component such as PE and PP and waste agricultural vinyl films. It is about the production of catalyst and process configuration. Inexpensive and highly active catalyst production method that can be applied to the process for producing low molecular hydrocarbon mixtures that can be used as liquid fuel from waste polymer materials or aromatic compounds that can be used as raw materials for petrochemical industry The invention relates to a process operating technology. The catalyst that can be used in the liquid catalyst decomposition process must have a wide outer surface and high activity to promote the primary decomposition of the polymer, and therefore the decomposition reaction must proceed even at a low temperature. In addition, the carbon deposition should not be too high or too many active sites. Therefore, in the present invention, a low-cost MFI zeolite is appropriately treated to increase the surface area, and the activity is high, but the carbon deposition is low, thereby rapidly decomposing the waste polymer material into low molecular hydrocarbons, and at the same time, preparing a catalyst having a high yield of liquid product.

In order to inexpensively prepare an MFI zeolite catalyst that can be applied to the liquid catalyst decomposition process of waste polymer materials, in the present invention, MFI zeolite was prepared without using an organic template material. In general, zeolites are synthesized by using inorganic cations or organic cations as template materials because the core formed around the template material or the aggregate of the template material is crystallized. Recently, a synthesis example using a nonionic organic material as a template has been reported, but MFI zeolite is generally synthesized using a material called tetrapropylammonium bromide (TPABr) as an organic template material. The aluminosilicate polymer is arranged around the organic cation to form a zeolite. The MFI zeolite is synthesized when the organic templating agent TPABr and alkali alumino silicate, a mixture of _{10TPABr · 16Na 2 O · Al 2} O 3 · 50SiO 2 · 3 ilgan hydrothermal synthesis mother liquor in 3000H ₂ O composition at 175 ℃. SiO ₂ / Al ₂ O ₃ molar ratio of the synthesized MFI zeolite is determined by the SiO ₂ / Al ₂ O ₃ molar ratio of synthetic mother liquor. However, TPABr is so expensive that it is not possible to inexpensively synthesize MFI zeolites using it.

When the zeolite is synthesized using the organic material as the template material, the pore of the zeolite can be formed by adsorbing the reactant and the product by burning it in the calcination process. In addition, since the acid point becomes the active point of the catalytic decomposition of the waste polymer, sodium ions contained in the zeolite must be ion exchanged with hydrogen ions so that strong acidity is obtained. Typically, ammonium nitrate is first ion-exchanged to introduce ammonium ions, which are then calcined at 550 ° C. to remove ammonia, thereby preparing a hydrogen ion-exchanged zeolite catalyst. However, since the acid zeolite needs to be calcined twice and ion-exchanged with ammonium nitrate in the process of producing the acidic zeolite, the treatment cost is high and the MFI zeolite catalyst cannot be manufactured at low cost.

Even when the MFI zeolite exchanged with hydrogen ions is prepared, if the particles are large, the catalytic activity is low and the activity is low in the liquid phase catalytic decomposition of the waste polymer material. If the particles are large, the outer surface that can participate in the primary decomposition of the polymer material is small, the activity is low, and the carbon deposition on the surface is severe, pore blockage occurs. Since it is not easy to grind the zeolite particles smaller than 1 μm even by mechanical grinding, it is necessary to adjust the synthesis conditions so that very small zeolite particles are produced or to make the outer surface of the synthesized zeolite appropriately.

The present invention provides a technique for preparing a catalyst suitable for application to a liquid catalyst decomposition reaction that converts waste polymer material into a low molecular hydrocarbon mixture.

That is, the MFI zeolite should be prepared at low cost, the exchange operation should be simple with hydrogen ions, and the outer surface area will be very wide, thereby providing a method for producing MFI zeolite that can be used as a catalyst for liquid phase catalytic decomposition. By using the MFI zeolite catalyst prepared according to the present invention, it is possible to decompose waste polymer materials into low-molecular hydrocarbons which can be used as liquid fuels at low temperatures, or by controlling the reaction conditions with secondary reactor catalysts to decompose waste polymer material decomposition products. Raw materials of the petrochemical industry can also be prepared by converting them into aromatic compounds.

1 is a diagram showing an X-ray diffraction pattern of the MFI zeolite synthesized in Example 1. FIG.

2 is a diagram showing a nitrogen adsorption isotherm of the synthesized MFI zeolite.

3 is a view showing an example of a small test apparatus for liquid phase catalytic decomposition of waste polymer materials using MFI zeolite of the present invention.

Figure 4 is a diagram showing the carbon number distribution of the liquid product of the decomposition reaction of the polymer material using the MFI zeolite prepared in Example 2.

Figure 5 is a schematic diagram showing an example of a continuous operation medium reactor of the liquid phase catalytic decomposition of waste polymer material.

6 is a view showing the distribution of the liquid product of the 430 ℃ HDPE decomposition reaction in the MFI catalyst further treated by various methods.

The present invention provides a method for preparing an MFI zeolite catalyst which can be used in the process of converting polyolefin waste polymer materials such as PE, PP, LDPE, and polyvinyl waste polymers such as agricultural vinyl, which is an EVA mixture, into a liquid fuel, which can be used as a liquid fuel. It is composed of a liquid catalyst decomposition process that is added to a molten polymer material at -450 ° C to be directly contacted and decomposed. The content of the present invention will be described by dividing it into a method for producing an MFI zeolite catalyst at low cost and a liquid catalyst decomposition process.

In the present invention, MFI zeolite was synthesized without using an organic template material. Using an organic template material, it is not possible to synthesize MFI zeolite at low cost. MFI zeolite was synthesized under the condition that alkaline cation could act as template material instead of organic template material because it could be secured as a catalyst for decomposition of waste polymer material at low cost. Typical composition of the synthetic mother liquor is _{3K 2 O · Al 2 O 3} · 50SiO 2 · 2150H 2 O. Unlike composition (4) reported in the literature, only KOH was used or mixed instead of NaOH, and the amount of water added was minimized. In the composition range, the molar ratio of SiO ₂ / Al ₂ O ₃ was 50 to 100, the molar ratio of K ₂ O / Al ₂ O ₃ was ₃ to 16, and the molar ratio of H ₂ O / Al ₂ O ₃ was adjusted to 2000 to 2200. When the NaOH was added to synthesize the Na ₂ O / Al ₂ O ₃ molar ratio was adjusted to _{4 ~ 20} range.

The use of an organic template material facilitates the synthesis of MFI zeolites due to the wide range of conditions. However, without the use of organic template materials, the synthesis composition and synthesis temperature conditions are very narrow, so the control of these factors is very important. In the present invention, MFI zeolite having excellent crystallinity could be synthesized without using an organic template material by hydrothermal reaction in the range of 160 to 200 ° C. for 1 to 3 days. However, if the composition is slightly changed, MFI zeolite is not produced or impurities such as quartz are present. Obtained. The synthetic mother liquor was aged or the core of MFI zeolite was added to facilitate the synthesis and reduce the crystallization time. At high temperatures, by reducing the water content of the synthetic mother liquor and feeding and aging the core, it was possible to synthesize high yields of MFI zeolite in a short time without using an organic template material, thereby significantly lowering the cost of producing the catalyst.

When the zeolite is synthesized using the organic template material, the organic template material must be burned and removed at 550 ° C or higher, and then ion exchanged with ammonium nitrate and calcined to exchange cations with hydrogen ions. Catalyst is made. In the present invention, since the MFI zeolite is synthesized without using the organic template material, no plastic operation is required. However, since the synthetic mother liquor contains sodium or potassium cations, an operation of exchanging them with hydrogen ions is necessary. In order to burn and remove the organic template material, it needs to be gradually heated up and processed at a high temperature for a long time. In addition, it is necessary to ion exchange with ammonium nitrate for cation exchange, and it is also expensive to remove ammonia by calcining it again. In order to simplify the operation and reduce the cost, the present invention treated the synthesized MFI zeolite in an aqueous solution of 0.2-3N hydrochloric acid at 40-80 ° C. to exchange sodium ions in the synthesized zeolite with hydrogen ions. Chlorine ions are removed during washing. This saves two firing processes. It is possible to prepare a catalyst that can be used because it removes the water adsorbed in the pores or the adsorbed material in the synthesis or post-treatment at 200 ~ 300 ℃ without firing at a high temperature. Therefore, the ion exchange using ammonium nitrate can be replaced by one hydrochloric acid solution treatment, and two high-temperature firing treatments can be replaced by one low-temperature drying, thereby greatly reducing the cost of producing the catalyst.

Synthesis of zeolites without the use of organic template materials generally results in zeolites with large particles. This is because the absence of organic template material makes it difficult to form the basic structure and the secondary unit structure of the zeolite, so the core concentration is low and grows for a long time until a large crystal is obtained. Although the core is small, the production rate is slow, but there is a lot of reactants around each core to grow into large particles. However, catalysts with high activity in the liquid phase decomposition of waste polymer materials should have large outer surfaces due to their small particles. Therefore, MFI zeolite synthesized without the use of organic template material has large particles and low activity, and thus is not useful for decomposition of waste polymer materials. In the present invention, the MFI zeolite synthesized without using an organic template material was treated with an alkaline solution to partially dissolve the surface to prepare a catalyst having a very large particle size but a large external surface area. To 20 g of MFI zeolite, 100 ml of 0.05-4.0 N sodium hydroxide or potassium hydroxide aqueous solution is added and treated at 60-80 ° C. for 0.5-8 hours to partially dissolve the zeolite surface and greatly increase the external surface area. Alkaline aqueous solution treated MFI zeolite was also very active in the catalytic cracking reaction.

In the liquid phase catalytic decomposition of the waste polymer material, the molten polymer material and the catalytic particles are in direct contact with each other. In particular, if the acid surface or structural defects are excessively strong on the surface of the catalyst, olefins generated during the decomposition of the waste polymer materials are strongly adsorbed and activated, and they polymerize with each other on the surface of the catalyst, so that polymers having a high boiling point are formed. If they are adsorbed on the surface of the catalyst for a long time, they are deposited with carbon through polymerization and dehydrogenation to shield the catalytic active site and lower the activity. In the present invention, in order to minimize carbon deposition, MFI zeolite exchanged with hydrogen ions was heated to reflux at 60 to 80 ° C. with a 2N boric acid aqueous solution. Although boric acid is weak in strength, it can also act as an acid or a base, and can neutralize strong acid sites, structural defects or base points that interact excessively with olefins, thereby greatly reducing the deterioration of activity due to carbon deposition of the catalyst. The boric acid treatment was effective in greatly increasing the decomposition conversion rate of the waste polymer material by reducing the carbon deposition and extending the catalyst life. If necessary, phosphorus was also supported to neutralize strong acid sites. After adding an appropriate amount of aqueous sodium dihydrogen phosphate solution to the dry catalyst, it was calcined to neutralize the acid point to suppress carbon deposition, which is most preferable for increasing the conversion rate of the liquid catalyst decomposition reaction.

(Example)

Hereinafter, an Example is given and this invention is demonstrated further more concretely.

Example 1

The catalyst to be used in the liquid phase catalytic decomposition of the waste polymer material was prepared by hydrothermal synthesis. A synthetic mother liquor was prepared by mixing 2555 g of colloidal silica (30 wt% of SiO ₂ ), 113 g of sodium aluminate, 95 g of potassium hydroxide, and 8000 g of water. While stirring at 350 rpm, 20 g of MFI zeolite was added as a core and stirred at room temperature for 24 hours. The synthetic mother liquor was put in a high pressure reactor and heated to 190 ° C. over 7 hours with stirring at 350 rpm, and hydrothermally synthesized at this temperature for 36 hours. After the reaction, the mixture was cooled, filtered and washed to prepare an MFI zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 50. After drying, the synthesized zeolite was 680 g and the silica standard yield was 85%. The X-ray diffraction peak position or intensity of the synthetic zeolite shown in FIG. 1 is well matched with the X-ray diffraction pattern and the position or intensity of the diffraction peak reported in the literature (5) to show that the MFI zeolite was produced. The average particle size of the synthetic MFI zeolite irradiated with a scanning microscope was about 5 μm.

Example 2

Synthetic mother liquor was prepared by mixing colloidal silica (SiO ₂ content 40 wt%) 1920 g, sodium aluminate 113 g, potassium hydroxide / sodium 95 g, and 9000 g of water. 20 g of MFI zeolite is added as a core and stirred at room temperature for 24 hours. The synthetic mother liquor was placed in a high pressure reactor and heated to 190 ° C. over 10 hours without stirring and hydrothermally synthesized at this temperature for 36 hours. After the reaction was cooled, filtered and washed to prepare an MFI zeolite. The synthesized zeolite had 720 g of silica based yield of 94%. The molar ratio of SiO ₂ / Al ₂ O ₃ was 50, the particle size of the synthetic zeolite irradiated with a scanning microscope was approximately 5 ㎛, it was confirmed that the MFI zeolite from the X-ray diffraction pattern. The results are shown in Table 1.

X-ray diffraction pattern of synthesized zeolite d (Å) 11.4 11.1 9.93 5.98 3.85 3.81 3.74 3.72 3.64 2.97 I / I。 16 42 31 15 100 79 53 60 31 23

Example 3

Example 2 The MFI zeolite was synthesized by the method, and the zeolite was synthesized again using the filtrate obtained by filtering and recovering the zeolite. Put the supernatant collected in the entire synthesis process and stirred for 24 hours the synthetic mother liquor prepared in Example 2. The supernatant is alkaline and contains the core of MFI zeolite, which can be used to recycle the wastewater, and the zeolite can be saved by using the fine zeolite in the filtrate as the core. The synthetic mother liquor was put in a high pressure reactor and heated to 190 ° C. for 10 hours, and hydrothermally synthesized at this temperature for 36 hours. After the reaction was cooled, filtered and washed to prepare an MFI zeolite. The synthesized zeolite was 700 g with a silica reference yield of 91%. The particle size of the synthetic zeolite irradiated with a scanning microscope was approximately 5 to 10 μm, and the MFI zeolite was confirmed from the X-ray diffraction pattern. The results are shown in Table 2.

X-ray diffraction pattern of synthesized zeolite d (Å) 11.19 9.99 6.37 6.00 5.71 4.27 3.85 3.82 3.73 3.65 I / I。 49 45 13 14 12 14 100 78 51 29

Example 4

MFI zeolite was synthesized from a synthetic mother liquor prepared by mixing 1920 g of colloidal silica (40 wt% of SiO ₂ ), 93 g of sodium aluminate, 95 g of potassium hydroxide / sodium, and 9000 g of water. 20 g of MFI zeolite is added as a core and stirred at room temperature for 24 hours. The synthetic mother liquor is placed in a high pressure reactor and heated to 190 ° C. for 10 hours, and hydrothermally synthesized at this temperature for 36 hours. After the reaction was filtered and washed to prepare an MFI zeolite. The synthesized zeolite was 700 g and the silica reference yield was 91%. The particle size of the synthetic zeolite irradiated with a scanning microscope was approximately 1 to 2 μm, and it was confirmed that it was an MFI zeolite from an X-ray diffraction pattern. The results are shown in Table 3.

X-ray diffraction pattern of synthesized zeolite (Example 4) d (Å) 11.8 9.99 6.00 5.69 3.85 3.82 3.75 3.64 3.05 2.98 I / I。 28 33 11 12 100 94 53 22 15 16

Example 5

MFI zeolite was synthesized using aluminum hydroxide instead of sodium aluminate. Colloidal silica (SiO ₂ content 40wt%) 1994 g, aluminum hydroxide 43 g, potassium hydroxide / sodium 264 g, 9000 g of water was mixed to prepare a synthetic mother liquor. 20 g of MFI zeolite was added as a core and stirred at room temperature for 24 hours. The synthetic mother liquor was placed in a high pressure reactor and heated to 190 ° C. for 10 hours, and hydrothermally synthesized at this temperature for 36 hours. After the reaction was filtered and washed to prepare an MFI zeolite. The synthesized zeolite had 550 g of silica based yield of 69%. The particle size of the synthetic zeolite irradiated with a scanning microscope was approximately 0.5 to 1.0 μm, and it was confirmed that it was MFI zeolite from an X-ray diffraction pattern. The results are shown in Table 4.

X-ray diffraction pattern of synthesized zeolite d (Å) 11.0 9.93 4.25 4.07 3.85 3.80 3.73 3.71 3.64 2.96 I / I。 33 22 16 22 100 80 52 59 33 20

The nitrogen adsorption isotherm of the synthesized MFI zeolite is shown in FIG. 2. Nitrogen adsorption isotherms of synthetic zeolites are all perfectly Langmuir type, with uniform micropore development. No mesoporous or macropores were observed. The surface area calculated from the nitrogen adsorption isotherm using the BET equation is 200-350 m ² / g, which is within the range of general zeolite surface area values.

Example 6

Liquid catalyst decomposition process of the waste polymer material was investigated using the apparatus shown in FIG. The reactor capacity was 100 ml and reacted with a polymer and a catalyst. The reactor was heated with a heating mantle and the reactor temperature was controlled with a PID controller. Gas is generated when the reactor temperature reaches around 300 ° C. When the reactor temperature reaches 380 ° C., a liquid product is obtained. The product was collected by liquefying in a condenser maintained at -4 ° C. Nitrogen gas was flowed into the carrier gas to prevent contact with air and the product flow was maintained smoothly.

The high-density polyethylene (HDPE), low-density polyethylene (LDPE) produced by Honam Petrochemical Co., Ltd. in the catalyst which acid-treated the MFI zeolite prepared in Example 2 and exchanged cations with hydrogen ions, and waste vinyl at Damyang Resources Reclamation Corporation After the first treatment, the liquid catalyst decomposition reaction of waste vinyl (DamP) prepared in granular form was investigated. Table 5 summarizes the results of liquid phase catalytic decomposition of these polymer materials.

Results of 380 ° C Liquid Phase Catalytic Degradation of Various Polymers Using the Catalyst Prepared in Example 2 catalyst Reactant HDPE LDPE PP PE wax DamP Conversion rate 99 99 18 100 16 Yield (%) Liquid Product 5841 5742 414 6832 115 Response time (minutes) 60 60 60 60 60

Reactant / catalyst: 10 g / 0.3 g

HDPE, LDPE, and PE waxes were all broken down in 60 minutes and converted to liquid or gaseous products. If the conversion is less than 100%, the gaseous residue is condensed in the catalyst and the reactor during the cooling process after the completion of the reaction. On the other hand, waste agricultural vinyl and PP had lower conversions than 20% and liquid product yields of 1-4% under the same conditions. The acid-treated MFI zeolite catalyst was suitable for the decomposition of HDPE and LDPE, but not for the liquid phase decomposition of waste agricultural vinyl and PP.

The product obtained from HDPE and LDPE was analyzed by gas chromatography, and the composition is shown in FIG. 4 for each carbohydrate. The product distribution was similar regardless of HDPE or LDPE. The gaseous products were hydrocarbons with 2 to 5 carbon atoms, of which C ₄ was the most common. Most liquid products were C ₅ -C ₁₂ hydrocarbons, but there were not many hydrocarbons above C ₁₂ . These may be used as fuels, or may be purified after decoloring and used as naphtha or industrial solvents.

Example 7

The catalyst prepared by the method described in Example 2 was subjected to phosphorus loading, boric acid treatment, and alkali treatment to be applied to the liquid phase decomposition of granular waste agricultural vinyl produced by Damyang Resource Regeneration Corporation, which is less decomposed than HDPE or LDPE. 100 ml of aqueous sodium dihydrogen phosphate solution was added to 10 g of MFI zeolite, dried and calcined at 550 ° C. to carry phosphorus on the zeolite. Boric acid treatment was performed with 2N aqueous boric acid solution. 100 ml of aqueous boric acid solution was added to 10 g of MFI zeolite, heated to reflux for 4 hours, filtered and dried, and then calcined at 550 ° C. to prepare a boric acid treatment catalyst. Alkaline treated MFI zeolites were prepared by treating zeolites with sodium hydroxide or potassium hydroxide aqueous solution. To 20 g of MFI zeolite, 200 ml of 0.5 N sodium hydroxide or potassium hydroxide aqueous solution was added, and the mixture was heated to reflux at 60 ° C. for 5 hours. After washing with deionized water, 0.5N hydrochloric acid aqueous solution was added, and the mixture was heated to reflux at 60 ° C. for 4 hours to exchange sodium ions with hydrogen ions. After filtration and washing with deionized water, it was dried for 5 hours at 200 ℃ was used as a catalyst.

0.3 g of a catalyst was added to 10 g of granular waste vinyl, and the liquid phase decomposition reaction was investigated in the small reactor of FIG. The reaction results are summarized in Table 6. From the reaction results, the decomposition efficiency of waste agricultural vinyl increased by about two times when phosphorus was supported or treated with boric acid in MFI zeolite. In particular, the yield of the liquid product was greatly increased to obtain 10% or more. Alkaline treatment was more effective, resulting in a marked increase in conversion of more than 97% in alkaline zeolite catalysts. The liquid product composition was similar to that of the acid treated catalyst, and the yield was 60%, which is much higher than that of other catalysts. The result of this large increase in catalytic activity is due to the partial dissolution of the surface by alkaline treatment, the outer surface being widened, and the strong acid point partially neutralized, and the carbon deposition is suppressed and the catalyst life is long.

Phosphorus-supported catalysts and boric acid-treated catalysts showed low activity in the liquefaction of waste agricultural vinyl, but high decomposition activity in HDPE and LDPE liquid phase decomposition reactions. Compared to the acid-treated zeolite catalysts, the activity of the catalyst and boric acid treatment catalyst was considerably higher, resulting in an increase in the amount of polymer material that can be treated per catalyst so that it can be used twice. A small amount of acetic acid, which is a decomposition product of ethylene vinyl acetate (EVA), is added to the liquid catalytic decomposition product of waste agricultural vinyl to maintain gloss, to extend the life, and to prevent the formation of water droplets. There is no difficulty in product separation because it is clearly distinguished from hydrocarbons, but the resulting acetic acid is adsorbed on the catalyst surface to promote carbon deposition, which shortens the catalyst life. Alkaline treated zeolite catalysts, however, have a wide outer surface, remove strong acidic points or structural defects that initiate carbon deposition, and thus increase durability to organic acids generated during decomposition, resulting in remarkably improved catalytic activity and lifetime.

Results of 380 ° C Liquid Phase Catalytic Degradation of Granular Waste Agricultural Vinyl on Acid, Boric Acid, Phosphate, and Alkaline MFI Zeolite Catalysts Acid treatment Boric acid treatment Phosphorus Alkaline treatment % Conversion 16 32 35 97 Yield (%) Liquid Product 115 1022 1223 5740 Response time (minutes) 60 60 60 60

Reactant / Catalyst: 10 g / 0.3 g

Example 8

Liquid catalyst decomposition of waste polymer was investigated in a continuous operation medium reactor.

5 shows a schematic diagram of this device. (In FIG. 5, each code | symbol is as follows.

1. Nitrogen cylinder, 2. Needle valve, 3. Flow meter, 4. Reactant injector, 5. Globe valve, 6. Catalyst injector, 7. Magnetic stirrer, 8. Reactor (2.5 L), 9. Shrouded heater, 10. Jacketed heater, 11. thermostat, 12. secondary reactor, 13. primary collector, 14. cooling water, 15. constant temperature circulation tank, 16. condenser, 17. secondary collector, 18. ball type gas storage tank)

Waste polymer material filled in the reactant hopper is melted at 200 ~ 400 ℃ by the internal heater to open the globe valve is put into the reactor at a constant speed. The top is kept solid and the bottom is adjusted to allow the fluid to melt and fluidize. The catalyst is fed to the reactor every 30 minutes via a catalyst inlet. The reactor is heated by a mantle at the bottom, a heater at the middle, a heating band for keeping warm at the top, and a temperature controller is installed for each part to independently control the temperature. Temperature sensor is attached to measure the temperature of five places including reactor and sample inlet at the same time. The waste polymer material supplied to the reactor is decomposed by the catalyst supplied in the reactor which is stirred at 200 to 900 rpm and converted into low molecular hydrocarbons. Inside the reactor, nitrogen gas was flowed at 5 to 60 ml / min to block air, especially oxygen. The produced low molecular hydrocarbons are pushed to the secondary reactor by their own pressure and carrier gas. The primary product is further reacted in contact with the catalyst charged in the secondary reactor to convert it into an aromatic compound or into a hydrocarbon mixture that can be used as a fuel such as diesel, kerosene and the like. The hydrocarbon mixture via the secondary reactor is sent to a two stage condenser. The high boiling point hydrocarbon and the coloring matter are separated in the primary condenser maintained at 100 to 160 ° C., and the liquid product is collected in the secondary condenser maintained at −3 to −8 ° C. The gas is sent to a cooled gas tank via a flow meter, hydrocarbons are condensed and stored, and nitrogen gas is released into the atmosphere.

The MFI zeolite prepared by the method described in Example 2 was subjected to hydrochloric acid treatment, impregnated paper, boric acid treatment, and alkali treatment by the method described in Example 7, and used as a catalyst for a continuous operation medium reactor. Table 7 summarizes the results of the batch reaction of HDPE in order to compare the catalytic function control effect in the medium reactor. 6 g of catalyst was added to 200 g of the reaction, and the reactor external temperature was maintained at 430 ° C. in 22 minutes. The agitator was operated when the internal temperature of the reactor reached 350 ° C. and the polymer material was melted. The liquid product began to condense into the collector, usually after 50 minutes of reaching the reactor internal temperature of 350 ° C., and the decomposition reaction was completed within 120 minutes.

Liquid Phase Catalytic Degradation of HDPE in a Medium Reactor Operated at 430 ° C catalyst Acid treatment Boric acid treatment Phosphorus Alkaline treatment % Conversion 100 100 100 100 yield(%) Liquid Product Primary Collector Second Collector 87482 87280 67480 27173 Gas product 18 20 20 27 Response time (minutes) 100 100 120 85

Reactant / catalyst: 200 g / 6 g.

Acid treatment, boric acid treatment, phosphorus supported, and alkali treated MFI catalysts started decomposition at the temperature of 350 ° C. in the reactor, and most of them were decomposed within 50 minutes. The conversion was the same at 100% for all catalysts. The yield of the liquid product was the best at 80% for the acid treated catalyst and the lowest at 73% for the alkaline treated catalyst. Instead, the time required for the reaction was 85 minutes (35 minutes from 350 ° C.) on the alkaline catalyst, which was the fastest decomposition rate. Alkaline treatment is thought to increase the porosity of the MFI catalyst to increase the diffusion rate of the polymer material, increase the outer surface area and increase the contact opportunities with the polymer material, thereby improving the decomposition activity. However, it is necessary to reduce the amount of catalyst or lower the reaction temperature so that the further decomposition reaction proceeds to increase the number of gaseous products to obtain a lot of liquid products.

The liquid product collected in the secondary collector was analyzed by gas chromatography. The product is a mixture of C ₅ to C ₁₂ hydrocarbons, regardless of catalyst, as shown in FIG. 6, with less than 2% of C ₁₃ or more hydrocarbons. Acid-treated MFI zeolites also have high activity in HDPE decomposition reactions, but are inferred to have a longer catalyst life in terms of higher C ₅ to C ₇ hydrocarbon fractions in boric acid and phosphorus supported catalysts. Although the appropriate catalyst should be selected in connection with the type and state of the reactants, the reaction conditions and the amount of the catalyst, the activity of the boric acid-treated catalyst was as good as the alkaline catalyst in the HDPE decomposition reaction.

Example 9

HDPE, LDPE, PP, DamP (Granular Waste Agricultural Vinyl Manufactured by Damyang Branch, Korea Resources Recycling Corporation), AndP (Korea Resources) Liquid catalysis of granular waste agricultural vinyl produced in Andong branch of regeneration was investigated. The reaction conditions are the same as in Example 8, Table 8 summarizes the results of the liquid phase catalytic decomposition reaction.

Results of 430 ° C Liquid Phase Catalysis of Various Polymers on Alkaline MFI Catalysts Reactant HDPE LDPE PP DamP AndP % Conversion 100 100 100 98 98 yield(%) Liquid Product Primary Collector Second Collector 27173 27375 37578 36366 26668 Gas product 27 25 22 32 30 Reaction end time (minutes) 85 120 90 140 140

Reactant / Catalyst: 200 g / 6 g

HDPE, LDPE, PP and waste agricultural vinyl all decomposed well under these reaction conditions. The yield of the liquid product was slightly lower in DamP and AndP, a vinyl product for waste farming. The waste agricultural vinyl contains EVA, which has a strong interaction with the MFI catalyst during the liquid phase catalytic cracking reaction, and thus stays in the catalyst for a long time.

The degradation rate of DamP and AndP is slower than that of HDPE and LDPE, which takes longer to complete the decomposition. Since acetic acid produced by decomposition of EVA contained in waste agricultural vinyl is adsorbed on the catalyst to promote carbon deposition, thereby degrading catalytic activity, the number of active points decreases and the reaction time is slowed.

Example 10

Decomposition reaction of waste Damping vinyl DamP on alkaline MFI catalysts with excellent polymer decomposition activity was investigated by changing the reaction temperature. In order to clearly compare the catalytic effect, the results of the catalytic reaction and the pyrolysis reaction are summarized in Table 9. If the catalyst is not used, it decomposes about 24% in 210 minutes at 400 ° C. However, the addition of an alkaline MFI catalyst completely decomposes the agricultural vinyl. The yield of the liquid product is also quite high, at 65%. When the reaction temperature is increased to 430 ° C and 475 ° C, the yield of pyrolysis reaction also increases, and the conversion rate reaches 59% at 475 ° C. However, long hydrocarbons are produced and most of the liquid product is collected in the primary collector. In contrast, the use of an alkaline MFI catalyst decomposes all in the range of 380-430 ° C., and the yield of the liquid product is about 65%. When the reaction temperature rises to 475 ° C., the decomposition reaction proceeds more and the liquid product decreases and the gas product yield slightly increases.

Liquid Phase Decomposition of Vinyl DamP for Waste Farming under Alkaline MFI Catalyst Usage and Pyrolysis Conditions Decomposition condition Alkaline MFI pyrolysis Reaction temperature (℃) 400 430 475 400 430 475 % Conversion 98 98 98 24 25 59 yield(%) Liquid Product Primary Collector Second Collector 36265 36366 45458 9817 11819 40949 Gas product 33 32 40 7 6 10 Response time (minutes) 210 140 90 210 140 120

Reactant / catalyst: 200 g / 6 g.

Example 11

The possibility of reusing the catalyst used once in the liquid phase catalytic decomposition of HDPE and DamP using alkaline MFI catalyst was investigated. 200 g of polymer and 6 g of catalyst were added to the method described in Example 8 to completely decompose the polymer, and then 200 g of only the polymer was added without a catalyst to investigate the residual decomposition activity of the used catalyst. It was. The reaction conditions are the same as in Example 8, Table 10 summarizes the reaction results when the primary reaction results and reuse.

Experimental Results of Reuse of Alkaline Treated MFI Catalyst in HDPE and DamP at 430 ℃ Reactant HDPE DamP Frequency of use Primary recycle Primary recycle % Conversion 98 99 98 73 yield(%) Liquid Product Primary Collector Second Collector 17071 27274 36164 392160 Gas product 27 25 34 13 Response time (minutes) 90 100 140 140

Reactant / Catalyst: 200 g / 6 g

In the alkaline MFI catalysts, the decomposition of HDPE was decomposed in both primary and reuse, and the liquid product yields were almost the same at 71% and 74%. On the other hand, in the decomposition of DamP, a waste agricultural vinyl containing EVA, the conversion rate was lowered from 98% to 73% when the catalyst was reused. The liquid product yields were similar, but due to the increased amount of primary collector capture, the catalytic activity was estimated to be significantly reduced. Alkaline-treated MFI catalysts lasted for a long time in the liquid phase catalytic cracking of PE or PP polymers without EVA, but the catalytic activity decreased more rapidly in the liquid phase catalytic cracking of waste vinyl containing EVA.

Example 12

The alkaline MFI catalyst used for the liquid phase decomposition of waste agricultural vinyl DamP and AndP containing EVA described in Example 9 was calcined and regenerated at 550 ° C. for 3 hours. The color of the catalyst used is slightly dark gray or brown, but when calcined, most of the carbon is removed and becomes pale gray. The reproducibility of the calcined catalyst was investigated from the results of liquid phase decomposition of waste agricultural vinyl in a small reactor shown in FIG. 3. Table 11 summarizes the results of the liquid phase catalytic decomposition reaction.

When the alkaline MFI catalyst used for the liquid phase catalytic cracking of waste agricultural vinyl DamP and AndP was calcined in air, the catalytic activity was significantly recovered, allowing further use. All of the HDPE supplied to the secondary were decomposed, irrespective of the type of waste agricultural vinyl, which was the reactant of the first decomposition reaction. However, if the reaction product of the secondary decomposition reaction was waste agricultural vinyl, the conversion was lowered to about 80%, indicating that the degradation activity was slightly decreased. When the first used catalyst is calcined and regenerated in air, the initial activity cannot be recovered 100%, but the residual catalyst activity is so high that a small amount of new catalyst can be replenished to be used for liquid phase catalytic decomposition of waste polymer materials.

Catalytic Decomposition of DamP and AndP at 380 ° C in Alkali MFI Catalyst Reactants of the first decomposition reaction DamP AndP Reactant used for calcined catalyst HDPE DamP HDPE DamP AanP % Conversion 99 87 99 95 79 yield(%) Liquid product 5346 4146 5742 4748 3742 Response time (minutes) 60 60 60 60 60

Reactant / catalyst: 10 g / 0.3 g.

As described above, the present invention treats zeolites appropriately to increase the surface area and thus has high activity but slow carbon deposition to rapidly decompose waste polymer materials into low-molecular hydrocarbons and at the same time provide an MFI catalyst with high yield of liquid product at low cost. . By using this catalyst, polyolefin waste polymers can be efficiently converted to low molecular hydrocarbons at low cost.

(references)

(1) J.-S. Shim, YS You, J.-H. Kim and G. Seo: Studies Surface Science and Catalysis, 82 , 465 (1998).

(2) YS You, J.-H. Kim and G. Seo .: "Liquid-Phase catalytic degradation of polyethylene wax over MFI zeolite with different particle sizes", Polymer Degradation Stability . in press (2000).

(3) YS You, J.-H. Kim and G. Seo .: "Liquid-Phase catalytic degradation of polyethylene wax over silica-modified zeolite catalysts", Polymer Degradation Stability . accepted (2000).

(4) FJ Machado, CM Lopez, Maria A. Centeno and C. Urbina .: " Template-free synthesis and catalytic behavior of aluminum-rich MFI-type zeolites ", Applied Catalysis General A , 181 , 1 (1999).

(5) MMJ Treacy, JB Higgins and RV Ballmoons .: "Collection of simulated XRD powder patterns for zeolites" , Elsevie r, 3rd., P. 522-525 (1996).

Claims (6)

3 to 16 (K ₂ O, Na ₂ O) · 0.25 to 1.0Al ₂ O ₃ · 50 to 100SiO ₂ · 2150 to 3000H ₂ O composition without organic template material for use as catalyst in liquid catalyst decomposition of waste polymer materials 0.5 to 4 g per 1 kg of the synthetic mother liquor was added to the synthetic mother liquor, and synthesized for 1 to 3 days at 175 to 205 ° C, followed by acid treatment with an aqueous solution of 0.2 to 3 N hydrochloric acid to exchange hydrogen ions. Method for producing an MFI zeolite catalyst, characterized in that. The process of claim 1 wherein the synthesis is by addition of phosphate as crystallization promoter instead of MFI zeolite core. The method of claim 1, wherein the MFI zeolite synthesized without the organic template material is further treated with an aqueous 0.2-4N metal hydroxide solution, followed by acid treatment with 0.2-3N hydrochloric acid. The method for preparing an MFI zeolite catalyst according to claim 1, wherein the MFI zeolite prepared without an organic template material is treated with 0.5-4N boric acid again. MFI zeolite catalyst carrying 0.05 to 5 wt% of phosphorus in the acid-treated MFI zeolite according to claim 1 Reactant conveying apparatus for introducing the polyolefin waste polymer material obtained by heating and melting the lower end of the hopper to 200 ~ 350 ℃ into a stirred batch reactor at a constant speed, A reactor in which the outer wall temperature is controlled to within ± 2 ° C by stirring the reactant and the alkaline MFI zeolite at 50 to 500 rpm, A post reactor to increase the yield of the liquid product by filling MFI or BEA zeolite exchanged with gallium ions, and to convert the olefin to an aromatic compound, Liquid product separator, which collects products continuously and grades by installing two-stage separators at different temperatures Liquid catalytic decomposition device of the waste polymer material consisting of.