KR100705775B1 - Production method of amorphous silica-alumina catalyst from coal fly ash for catalytic pyrolysis of waste plastics - Google Patents

Abstract

The present invention relates to a method for producing an amorphous silica alumina catalyst from coal fly ash, and more particularly, to a method for preparing an amorphous silica alumina catalyst that can be used in waste plastic pyrolysis oilification process using coal fly ash and alkali. On the other hand, the present invention includes a method of obtaining an oil from waste plastic by using the amorphous silica alumina catalyst obtained by the method for preparing an amorphous silica alumina catalyst obtained from coal fly ash in a waste plastic pyrolysis oilification process.

The present invention can be used to prepare a low cost amorphous silica alumina catalyst from coal fly ash and the amorphous silica alumina catalyst prepared by the above method in waste plastic pyrolysis oilification process to obtain light oil level pyrolysis oil from waste plastic.

The present invention can reduce the production cost of the catalyst required for waste plastic pyrolysis process by using an amorphous silica alumina catalyst prepared from coal fly ash as waste as a catalyst used in the oilification process of pyrolysis of waste plastic. In addition, the amorphous silica alumina catalyst prepared according to the present invention can also help to prevent environmental pollution by manufacturing using coal fly ash as waste.

Description

Production method of amorphous silica-alumina catalyst from coal fly ash for catalytic pyrolysis of waste plastics}

1 is a SEM photograph of the amorphous silica alumina prepared in Example.

2 is a graph showing the results of XRD diffraction analysis of the amorphous silica alumina catalyst prepared according to an embodiment of the present invention.

3 is a weight loss measurement result according to the temperature when the polyethylene is thermally decomposed using the amorphous silica alumina catalyst prepared according to the embodiment of the present invention, the temperature when the thermal decomposition of the polyethylene using a commercial catalyst Is a graph showing the result of weight loss measurement according to the weight loss amount according to the temperature when the thermal decomposition of polyethylene in the non-catalyst state without using a catalyst.

Figure 4 is a boiling point distribution of oil obtained by catalytic pyrolysis of polyethylene waste using a catalyst prepared according to an embodiment of the present invention, boiling point distribution of oil obtained by pyrolyzing polyethylene waste in the absence of a catalyst Results and a graph showing the boiling point distribution of the oil obtained by catalytic pyrolysis of polyethylene waste using a commercial catalyst.

The present invention relates to a method for producing an amorphous silica alumina catalyst from coal fly ash, and more particularly, to a method for preparing an amorphous silica alumina catalyst that can be used in waste plastic pyrolysis oilification process using coal fly ash and alkali.

On the other hand, the present invention includes a method of obtaining an oil from waste plastic by using the amorphous silica alumina catalyst obtained by the method for preparing an amorphous silica alumina catalyst obtained from coal fly ash in a waste plastic pyrolysis oilification process.

The recycling method of waste plastics is intact or processed and recycled, a thermal recycling method for recovering energy through incineration or pyrolysis, and a chemical recycling method for decomposing waste plastics into monomers.

When the thermal recycling method is further subdivided among the waste plastic recycling methods, it can be classified into an energy recovery method by incineration, a dry gas gasification method, a method of physically forming and processing a fuel, and a pyrolysis oilification method.

Waste plastic pyrolysis method produces waste oil by cutting carbon bonds of polymers by heating waste plastics above 400 ℃ in the air blocked state, and there is no need to separate waste plastics by type and there is no fear of soil or air pollution. The advantage is that liquid fuel can be recovered.

However, in the case of polyolefin waste plastics such as polyethylene and polypropylene, a large amount of wax components are contained in the pyrolysis-producing oil, which solidifies inside the condenser and causes clogging, making it difficult to operate stably and having low fluidity at room temperature. No problem has been pointed out.

Therefore, in the case of pyrolysis oilification of polyolefin waste plastics, it is necessary to decompose wax powder into light oil, which can be achieved through catalytic cracking with a catalyst. Although cracking catalysts such as synthetic zeolites and silica alumina catalysts have been mainly used as catalysts used for such pyrolysis, it is pointed out that the economical deterioration of the process due to the use of expensive commercial catalysts is a major problem.

Meanwhile, a number of methods for manufacturing low-cost zeolites have recently been developed using coal fly ash, which is a waste, as a raw material for alumina and silica. For example, a method of preparing a zeolite by hydrothermally treating a slurry of a coal fly ash and an aqueous alkali solution (Korean Patent No. 10-0274118), and a method of synthesizing zeolite after washing the coal fly ash with a strong acid (Japanese Patent Laid-Open No. 7-165418) Etc.

However, the above-mentioned conventional method mainly uses A-type zeolite or NaP1 zeolite, which is used as an adsorbent or molecular sieve, and also has a disadvantage that the synthesized coal fly ash-derived zeolite is not suitable for use as a cracking catalyst due to its low purity. It is pointed out.

Amorphous silica alumina catalyst is one of amorphous aluminum silicate, has an acid (acid) generated by the combination of silicon atoms and aluminum atoms has been widely used as a cracking catalyst in the chemical industry.

As a method for synthesizing such an amorphous silica alumina catalyst, a method of chemically adsorbing alumina hydroxide on a silica surface, a method of precipitating an alumina hydrogel on a silica hydrogel, a method of gelling an alkali silicate and an aqueous solution of an aluminum salt, an ester Hydrolysis method, and the third and fourth of them are not suitable for the waste plastic pyrolysis oilification process for treating waste due to the burden on the method or price generally used when preparing a commercial catalyst. .

The present inventors have made diligent research efforts to solve the problems of the prior art, and as a result, a large amount of silica and alumina source are extracted by reacting coal fly ash with alkali at high temperature, and after co-precipitation, the remaining impurities are removed to activate the catalytic activity. It was confirmed that this excellent amorphous silica alumina catalyst could be stably synthesized.

In addition, it was confirmed that the amorphous silica alumina catalyst of the present invention can be used in the catalytic pyrolysis oilification process of waste plastic to effectively produce light oil level oil.

Therefore, the main object of the present invention is to prepare a low-cost amorphous silica alumina catalyst from coal fly ash and to use the amorphous silica alumina catalyst prepared by such a method in the waste plastic pyrolysis oilification process from waste plastic to light oil level pyrolysis oil. It is to provide a way to get.

In particular, by using an amorphous silica alumina catalyst prepared from coal fly ash, which is a waste, as a catalyst used in an oilification process for pyrolyzing waste plastic, it is possible to reduce the production cost of the catalyst required for waste plastic pyrolysis process. In addition, the amorphous silica alumina catalyst prepared according to the present invention can also help to prevent environmental pollution by manufacturing using coal fly ash as waste.

The present invention for achieving the above-mentioned object is to produce an amorphous silica alumina catalyst from a coal fly ash, characterized in that the coal fly ash-alkali reactant to obtain a coal fly ash-alkali reactant by reacting the coal fly ash with an alkali; It shows how to do it.

In preparing the amorphous silica alumina catalyst of the present invention, the main materials may be coal fly ash and alkali.

Alkali is not particularly limited in the above, but the coal fly ash is in the form of a solid, it is preferable to use an alkali in the form of a solid also reacts with coal fly ash.

In the present invention, the coal fly ash-alkali reactant may be obtained by reacting the coal fly ash with an alkali at 500 to 700 ° C. for 0.5 to 2 hours. At this time, 70 to 300 parts by weight of alkali may be reacted with respect to 100 parts by weight of coal fly ash to obtain a coal fly ash-alkali reactant.

When using less than 70 parts by weight of alkali based on 100 parts by weight of coal fly ash in the production of the amorphous silica alumina catalyst of the present invention, there is a problem of insufficient silica and alumina ions required for preparing the amorphous silica alumina catalyst, and alkali is used based on 100 parts by weight of coal fly ash. When used in excess of 300 parts by weight, the characteristics of the amorphous silica alumina catalyst due to the increase in the amount of alkali used are not improved. Therefore, in the preparation of the amorphous silica alumina catalyst of the present invention, alkali is preferably reacted with 70 to 300 parts by weight based on 100 parts by weight of coal fly ash to obtain a coal fly ash-alkali reactant.

Alkali is not particularly limited in the preparation of the amorphous silica alumina catalyst of the present invention. As an example of alkali in the preparation of the amorphous silica alumina catalyst of the present invention, any one or more selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, laundry sodium, calcium hydroxide and barium hydroxide may be used.

In preparing the amorphous silica alumina catalyst of the present invention, a coal fly ash-alkali reactant having silica and alumina ions may be obtained by reacting coal fly ash and alkali at 500 to 700 ° C. for 0.5 to 2 hours.

The coal fly ash-alkali reactant having the silica and alumina ions is dissolved in purified water and then aged to synthesize an amorphous silica alumina catalyst. At this time, the maturation of the coal fly ash-alkali reactant may be performed to synthesize an amorphous silica alumina catalyst from silica and alumina ions. As an example of the aging conditions in the present invention can be carried out for 20 to 30 ℃ for 6 to 36 hours.

Meanwhile, the amorphous silica alumina catalyst prepared above may further be calcined to enhance strength. At this time, the firing conditions are sufficient if the amorphous silica alumina catalyst can improve the strength. As an example of such firing conditions in the present invention, amorphous silica alumina may be calcined at 600 to 700 ° C. for 4 to 8 hours.

According to the present invention, an amorphous silica alumina catalyst is manufactured under various conditions using a coal fly ash and an alkali. In order to obtain an amorphous silica alumina meeting the object of the present invention, the amorphous silica may be prepared under the conditions of the above numerical range from a coal fly ash and an alkali. It is preferable to produce alumina.

On the other hand, the amorphous silica alumina of the present invention prepared by the above-mentioned method has a BET specific surface area of 42-126 m whose specific surface area, pore volume, average pore diameter and physical properties for X-ray diffraction are measured by ASTM regulations. ² / g, pore volume 0.16 to 0.50 cm ³ / g, average pore diameter: 152 ~ 180 Å, X-ray diffraction properties of amorphous properties.

The present invention includes a method of obtaining oil from waste plastic by heating the waste plastic under anoxic conditions in the presence of an amorphous silica alumina catalyst prepared in the above method in obtaining oil from waste plastic.

As an example of oil obtained from the waste plastic of the present invention, oil may be obtained from waste plastic by heating the waste plastic under anoxic conditions in the presence of 5 to 40 parts by weight of the above-mentioned amorphous silica alumina catalyst with respect to 100 parts by weight of waste plastic. .

In the above waste plastics may be used waste plastics including olefin waste plastics. In the present invention, waste plastics may be used as waste plastics including any one or more olefin waste plastics selected from polyethylene and polypropylene as one example of olefin waste plastics.

In the above, the waste plastic can be heated in anoxic conditions. The reason why the waste plastic is heated in anoxic condition is that the combustion reaction occurs rapidly in the oxygen condition so that the waste plastic is converted to carbon dioxide, whereas when heated to the anoxic condition, it is possible to recover expensive materials of fuel oil properties. In this case, as an example of anoxic conditions, waste plastic may be placed in a pyrolysis reactor and an inert gas may be supplied to the pyrolysis reactor for smooth movement of the pyrolysis product and maintenance of anoxic conditions.

In the present invention, as an example of the inert gas, any one gas selected from nitrogen, argon, helium, and neon may be used.

The waste plastic is heated at a temperature of 350 to 450 ° C. under anoxic conditions in the presence of an amorphous silica alumina catalyst prepared according to the present invention to pyrolyze the waste plastic to obtain a light oil pyrolysis oil.

Pyrolysing waste plastics under various conditions to obtain pyrolysis oil from the waste plastics of the present invention. The waste plastics are pyrolyzed by heating to an oxygen-free condition and a temperature in the above-described numerical range in the presence of the above-mentioned amorphous silica alumina catalyst of the present invention. Pyrolysis oil of light oil level can be obtained.

Hereinafter, the content of the present invention will be described in detail through examples. However, these are intended to explain the present invention in more detail, and the scope of the present invention is not limited thereto.

Example 1 Preparation of Amorphous Silica Alumina Catalyst from Coal Fly Ash

A mixture of 100 g of coal fly ash and 120 g of sodium hydroxide produced in a Boryeong thermal power plant was homogeneously mixed and heated to a high temperature in a kiln for 1.5 hours to obtain a coal fly ash-sodium hydroxide fusion.

The coal fly ash-sodium hydroxide fusion was dissolved in distilled water and then aged at room temperature for 8 hours to coprecipitate the catalyst. In order to remove the unreacted sodium hydroxide contained in the mixture, it was washed several times with distilled water and solid-liquid separated by filter paper to separate the impurity solution and the catalyst.

The amorphous silica alumina catalyst of the present invention was obtained by heating at 600 ° C. for 4 hours in order to enhance the mechanical properties of the catalyst and to remove residual impurities.

1 shows an SEM image of the amorphous silica alumina catalyst prepared above.

Chemical compositions of the coal fly ash derived from Boryeong thermal power plant and the amorphous silica alumina catalyst obtained in the above examples are shown in Table 1 below.

Table 1. Chemical Composition of Amorphous Silica Alumina Catalysts Synthesized with Coal Fly Ash

SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ MgO CaO K ₂ O Na ₂ O Etc Ig. Loss Coal fly ash 53.56 27.71 5.53 0.91 4.50 0.94 0.37 0.60 5.88 catalyst 56.1 30.8 6.14 0.58 0.97 0.10 0.17 1.07 4.07

Example 2 Physical Characterization of Amorphous Silica Alumina Catalysts Prepared from Coal Fly Ash

In order to understand the physicochemical properties of the amorphous silica alumina catalyst prepared in Example 1, physical properties such as X-ray diffraction analysis and BET surface area measurement were performed.

As can be seen in FIG. 2, the XRD diffraction analysis of the catalyst prepared in Example 1 shows that the amorphous silica alumina catalyst has a gentle peak and thus has no amorphous properties.

On the other hand, as a result of analyzing the physical properties of the amorphous silica alumina catalyst prepared in Example 1 according to the ASTM-related regulations, the amorphous silica alumina catalyst prepared in Example 1 has a surface area of 126m ² / g, 0.50cm ³ / g It was found to have a pore volume and a pore diameter of 156 mm 3.

Example 3 Analysis of Pyrolysis Activity of Amorphous Silica Alumina Catalyst Prepared from Coal Fly Ash

In order to confirm the pyrolysis activity of the amorphous silica alumina catalyst obtained in Example 1, plastic catalytic pyrolysis was performed using a thermogravimetric analyzer (Rubotherm, Germany).

5 g of low density polyethylene and 0.5 g of the amorphous silica alumina catalyst prepared in Example 1 were charged into a 22.6 ml (ml) platinum container, and nitrogen gas was supplied at a flow rate of 100 ml (ml) per minute to maintain anoxic conditions. Using an electric furnace, the temperature was increased by 5 ° C. per minute to 600 ° C. and weight loss was measured according to the temperature.

For comparison, only 5 g of low-density polyethylene without a catalyst, 0.5 g of Y-type zeolite (HY (5.1), Zelist, USA) widely used as a cracking catalyst, and 5 g of low-density polyethylene were charged under the same conditions. Pyrolysis experiments were conducted.

As shown in FIG. 3, when the amorphous silica alumina catalyst prepared in Example 1 was used, not only pyrolysis was started at a temperature significantly lower than that of the non-catalyst but also a similar pyrolysis initiation temperature was obtained when using a commercial catalyst HY catalyst. It was shown that the excellent activity of the catalyst synthesized by the present invention can be demonstrated.

Example 4 Pyrolysis of Waste Plastic Catalytic Catalyst by Amorphous Silica Alumina Catalyst Prepared from Coal Fly Ash

5 g of the catalyst prepared in Example 1 and 50 g of low density polyethylene waste were charged to a reactor having a capacity of 1 liter (L), and the temperature of the reactor was heated and maintained at 420 ° C. using an electric furnace.

Nitrogen gas was fed into the reactor at 60 milliliters (ml) per minute to ensure smooth transport of the pyrolysis product and maintenance of anoxic conditions.

The non-condensable gas which was not condensed in the pyrolysis product was discharged to the atmosphere, and the condensable gas was condensed with a condenser and collected together with the liquid product.

The boiling point distribution of the liquid product collected by the ASTM D2887 method was measured. For comparison, pyrolysis was carried out under the same conditions for charging 50 g of plastic waste without a catalyst, 5 g of Y-type zeolite (HY (5.1), Zelist, USA) and 50 g of plastic waste.

As can be seen from the result of the non-point distribution graph shown in FIG. 4, the amorphous silica alumina catalyst prepared in Example 1 exhibited superior activity than that of a commercial catalyst without using a catalyst, as well as a non-catalyst. It was possible to recover high levels of light diesel oil at high yield.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the invention described in the claims below. It will be appreciated that it can be changed.

As described and demonstrated in the above examples, according to the present invention, amorphous silica alumina catalysts having excellent catalytic activity can be obtained in large quantities from low cost coal fly ash, and the obtained catalysts can be used to light oil level from plastic waste. Can produce liquid fuels that can be widely used in waste recycling processes.

On the other hand, the amorphous silica alumina catalyst of the present invention can be obtained by using coal fly ash, which is a waste material, and can also help to reduce environmental pollution caused by coal fly ash.

Claims (10)

A method of producing an amorphous silica alumina catalyst from a coal fly ash comprising the step of reacting the coal fly ash with alkali at 0.5 to 2 hours at 500 to 700 ° C. to obtain a coal fly ash-alkali reactant. delete The method according to claim 1, wherein 70 to 300 parts by weight of alkali is reacted with respect to 100 parts by weight of coal fly ash. The method of claim 1, wherein the alkali is any one or more selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, laundry sodium, calcium hydroxide and barium hydroxide. The method of claim 1, wherein the aging of the coal fly ash-alkali reactant is carried out at 20 to 30 ° C for 6 to 36 hours. The method of claim 1, further comprising the step of removing impurities after aging and calcining at 600 to 700 ° C. for 4 to 8 hours. In obtaining oil from waste plastic, 70 to 300 parts by weight of any one or more alkali salts selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, laundry sodium, calcium hydroxide and barium hydroxide are reacted at 500 to 700 ° C. for 0.5 to 2 hours with respect to 100 parts by weight of coal fly ash. A process for obtaining an oil from waste plastic by heating the waste plastic under anoxic conditions in the presence of an amorphous silica alumina catalyst obtained by obtaining an alkali reactant and co-precipitating and aging the reactant. According to claim 7, 70 to 300 parts by weight of any one or more alkalis selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, laundry sodium, calcium hydroxide, barium hydroxide per 100 parts by weight of coal fly ash 0.5 to 2 hours of reaction at 700 ° C. to obtain a coal fly ash-alkali reactant, and the waste plastic is heated under anoxic conditions in the presence of 5 to 40 parts by weight of an amorphous silica alumina catalyst obtained by coprecipitation and aging of the reactant to obtain oil from waste plastic. Way. The method according to claim 7 or 8, wherein the waste plastics comprise olefinic waste plastics. The method of claim 7 or 8, characterized in that the waste plastic is heated in the presence of any inert gas selected from nitrogen, argon, helium and neon as anoxic conditions.

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