KR100868236B1 - Process method for adsorption agent from the pyrolysis residue of waste polystyrene - Google Patents

Abstract

A method of manufacturing adsorber is provided to recycle pyrolysis residue obtained thermally decomposes waste polystyrene as a raw material of the adsorber, to reduce environment contamination problem by waste, to secure steadily the raw material of the adsorber and to save a production cost. A waste polystyrene melt is injected in a pyrolysis reactor and a styrene monomer and a pyrolysis residue are manufactured at 350 ~ 400 °C. The manufactured pyrolysis residue is heated at 900 ~ 1000 °C under an inert atmosphere and separated into a volatile component and a solid carbide. The solid carbide perform an activation reaction at 900 ~ 1000 °C by an oxidative gas.

Description

Process method for adsorption agent from the pyrolysis residue of waste polystyrene}

1 schematically shows a pyrolysis process diagram of waste polystyrene according to the present invention.

BRIEF DESCRIPTION OF THE SIGNS OF FIG. 1

1 injection molding machine 2 reactor 3 heat exchanger

4 oil storage tank 5 distillation apparatus

The present invention is a series of processes in which waste polystyrene is pyrolyzed to prepare styrene monomer and pyrolysis residue, and the pyrolysis residue is heated and separated to recover volatiles and solid carbide, and then the activation reaction between the solid carbide and the oxidizing gas is performed. The present invention relates to a method for producing an adsorbent having a specific surface area, a pore volume, and the like equivalent to that of the related art, and securing a stable raw material, reducing production costs, and being environmentally friendly.

Recently, our country has generated about 300,000 tons of Styrofoam waste, such as agricultural and household products, packaging and building sound insulation. Some of these polystyrene-based plastic wastes are recycled to recycled resins, lightweight concretes, adhesives, etc. by physical treatment, but are finally treated by landfilling or incineration, causing environmental problems. Therefore, the polystyrene-based plastic waste can be recovered and recycled as a raw material such as styrene monomer through a chemical recycling technology through a chemical treatment step, thereby greatly improving economic efficiency and environmental friendliness.

There are various literatures on how to recover the styrene monomer by pyrolyzing the waste polystyrene-based plastic waste (Korean Patent Registration No. 524698, Korean Patent Registration No. 468047 and Korean Patent Registration No. 57207). At this time, a pyrolysis residue is obtained together with the styrene monomer as a target by the pyrolysis process, and various studies on the application thereof are currently insufficient. Therefore, in the present invention, to prepare an adsorbent using a pyrolysis residue.

Accordingly, the present inventors have studied about the utilization of pyrolysis residues generated in a large amount in the pyrolysis process of recovering styrene monomer from polystyrene plastic waste, and the components of the pyrolysis residues are 80% or more of carbon (C), Considering that oxygen and hydrogen are contained, it was intended to prepare a carbon-based soil modifier using the same.

In the preparation of the soil modifier, the pulverized waste polystyrene is melted and subjected to a pyrolysis reaction to prepare a styrene monomer and a pyrolysis residue. The pyrolysis residue is heated in an inert atmosphere, separated and recovered as a volatile component and a solid carbide. It is a series of processes for producing soil modifier by activating reaction of solid carbide with oxidizing gas, and it is possible to maintain physical properties such as specific surface area and pore volume more than the same as before, and it basically reduces environmental pollution problem by using waste. The present invention was completed by knowing that it is possible to secure stable raw materials and reduce production costs of the adsorbent.

Accordingly, an object of the present invention is to provide a method for producing an adsorbent in a stable supply and environmentally friendly manner of raw materials using a pyrolysis residue generated in a large amount of pyrolysis of waste polystyrene.

The present invention is a step of preparing a styrene monomer and pyrolysis residue by injecting the waste polystyrene melt into a pyrolysis reactor, pyrolysis in the range of 350 ~ 400 ℃; The prepared pyrolysis residue is heated in an inert atmosphere in the range of 900 to 1000 ° C. to separate and recover the volatile component and the solid carbide; And a three step of preparing an adsorbent by performing an activation reaction in the range of 900 to 1000 ° C. with the oxidizing gas.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for preparing a soil improving agent using pyrolysis residue obtained by pyrolyzing waste polystyrene. Specifically, by using the pyrolysis residue of waste polystyrene as a raw material of the adsorbent, not only can greatly reduce the environmental pollution burden, but also the raw materials can be stably sourced in Korea, thereby reducing the burden on the environment and procuring domestic raw materials.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

First, the waste polystyrene melt is introduced into a pyrolysis reactor and pyrolyzed in the range of 350 to 400 ° C. to prepare styrene monomer and a pyrolysis residue.

1 is a process diagram schematically showing a pyrolysis process of waste polystyrene according to the present invention. The present invention will be described in more detail with reference to FIG.

The pyrolysis process used in the present invention consists of an injection molding machine (1), a reactor (2), a heat exchanger (3), an oil reservoir (4) and a distillation apparatus (5). Looking at the pyrolysis process to obtain the styrene monomer using the device configured as described above, first, the waste polystyrene in the form of ingot (crushed) in an irregular shape of about 1 cm or less in size to the injection molding machine of 220 ~ 280 ℃ temperature (1 Injecting into the reactor (2) while melting using; Thermally decomposing the charged reactant at a temperature of 350 to 400 ° C .; Collecting the oil obtained by liquefying the decomposed gas through a heat exchanger (3) in an oil storage tank (4); And recovering the styrene monomer from the collected oil in the distillation apparatus (5).

Specifically, the ingot of waste polystyrene, which is a raw material, is first crushed into a irregular shape of 2 cm or less with a crusher, and the metal contained in the raw material using a shredder equipped with a magnet secondly. Remove foreign substances. This is because the presence of metal foreign matters in the raw material causes a problem in transporting by catching the screw of the injection molding machine in the process of transporting the injection molding machine to the reactor with melting.

The injection molding machine serves to transfer waste polystyrene particles having a size of 2 cm or less to the reactor with melting. The injection molding machine maintains a temperature of 220 to 280 ° C., when the temperature is less than 220 ° C. Not only does it cause a problem with smooth transfer without smooth melting, but it may also cause a load on the motor to rotate the screw, and if it exceeds 280 ° C., pyrolysis may occur before entering the reactor.

The pyrolysis reactor is generally used in the art and is not particularly limited, but the present invention is more effective to use a continuous stirring reactor type. This pyrolysis reaction proceeds to the reaction of free radicals by converting waste polystyrene into light hydrocarbons having a low molecular weight and low boiling point. The pyrolysis reaction is performed at a temperature in the range of 350 to 400 ° C., if the temperature is less than 350 ° C., a large amount of unreacted organic matter and a low content of carbon solids are obtained. In this case, the condensation efficiency is lowered, and as a result, the yield of the generated oil is lowered.

Pyrolysis residues generated from the reactor (2) of the waste plastic pyrolysis process as described above contains a large amount of about 75 to 85% by weight of carbon can be expected to produce a high production yield when used as a raw material for the preparation of the adsorbent. In addition, the pyrolysis residue has a softening point of 250 ° C or higher, specifically 250 to 350 ° C, and a toluene insoluble content of 60% by weight or more, specifically 60 to 90% by weight, preferably 70 to 90% by weight. . The insoluble content of the toluene is necessarily required to maintain the insolubilization phenomenon in the carbonization process. The pyrolysis residue as described above exhibits such a range as carbon content, softening point and toluene insoluble content, and thus is easily manufactured with an adsorbent.

The method of preparing the adsorbent using the pyrolysis residue obtained from the waste plastic as described above is as follows.

The prepared pyrolysis residue is heated to 900 ~ 1000 ℃ range in an inert atmosphere, and separated and recovered as volatile components and solid carbide. Specifically, the pyrolysis residue is added to a rotary kiln capable of continuous operation, and then heated to 900 to 1000 ° C. under an inert atmosphere such as nitrogen and argon to discharge volatile components in the residue in gaseous form. Obtained as a carbide in solid form. If the heating temperature is less than 900 ℃ carbonization reaction occurs incompletely, if it exceeds 1000 ℃ it is preferable to maintain the above range because problems such as excessive energy costs and carbonization shorten the life.

Next, the solid carbide is activated with an oxidizing gas in the range of 900 to 1000 ° C. to prepare an adsorbent. Specifically, when the solid carbide is reacted with the oxidizing gas, the active point of the carbide reacts with the oxidizing gas to convert carbon dioxide, carbon monoxide, water, etc., and a so-called activation process is performed in which fine pores are formed therein. As the activation process proceeds, the solid component of the carbide vaporizes, thereby decreasing the solid weight and increasing the pore volume and specific surface area.

The carbonization and activation are specifically carried out using a rotary furnace or a multistage furnace. In addition, the oxidizing gas may be water vapor, carbon dioxide, air and combustion gas, and the like may be light oil, natural gas, electricity or the like.

The activation temperature is carried out in the range of 900 ~ 1000 ℃ bar, if the temperature is less than 900 ℃ activation reaction rate is too slow, productivity is reduced, when the temperature exceeds 1000 ℃ activation reaction rate is too fast to control the physical properties difficult It is good to keep the above range because occurs.

The adsorbents prepared according to the invention have a specific surface area in the range of 250 to 450 m 2 / g and a pore volume in the range of from 0.18 to 0.35 cc / g.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1

Ingot-type waste polystyrene was crushed into an irregular shape having a size of about 1 cm or less, melted in an injection molding machine having a temperature of 250 ° C., and introduced into a reactor having a temperature of 350 ° C., and pyrolyzed at 350 ° C. for oil obtained from a styrene monomer in a distillation apparatus. Was recovered and pyrolysis residue was obtained from the reactor. 300 g of the residue carbide thus prepared was injected into a continuous rotary furnace at a rate of 10 g / min, and was kept at 950 ° C. for 1 hour in a nitrogen atmosphere to obtain 142 g of solid carbide.

The carbide was rotated in a batch rotary furnace at a speed of 10 rpm per minute and activated with carbon dioxide gas at 950 ° C. for 1 hour to obtain 59 g of an adsorbent. The specific surface area of the prepared adsorbent was 415 m 2 / g, and the pore volume was 0.31 cc / g.

Example 2

Styrene monomer was obtained by distilling the oil obtained by crushing ingot-type waste polystyrene into an irregular shape having a size of about 1 cm or less, and thermally decomposing the oil at 370 ° C. while melting it in an injection molding machine having a temperature of 250 ° C. and feeding it into a reactor at a temperature of 370 ° C. Recovered and the residue carbide was obtained from the reactor. 300 g of the residue carbide thus prepared was injected into a continuous rotary furnace at a rate of 10 g / min, and held at 950 ° C. for 1 hour in a nitrogen atmosphere to obtain 211 g of solid carbide.

The carbide was rotated at a rate of 10 rpm per minute in a batch rotary furnace and activated at 950 ° C. for 1 hour with carbon dioxide gas to obtain 91 g of an adsorbent. The specific surface area of the prepared adsorbent was 430 m 2 / g, and the pore volume was 0.33 cc / g.

Example 3

Styrene monomer was obtained by distilling the oil obtained by crushing ingot-type waste polystyrene into an irregular shape having a size of about 1 cm or less and thermally decomposing the oil at 400 ° C. while melting it in an injection molding machine having a temperature of 250 ° C. and feeding it into a reactor having a temperature of 400 ° C. Recovered and the residue carbide was obtained from the reactor. The softening point of the residue carbide thus prepared was 251 ° C., and the toluene insoluble content was 85%. Thus prepared 300 g of the residue was injected into a continuous rotary furnace at a rate of 10 g / min and held at 950 ° C. in a nitrogen atmosphere for 1 hour to obtain 242 g of solid carbide.

The carbide was rotated at a rate of 10 rpm per minute in a batch rotary furnace and activated at 950 ° C. for 1 hour with carbon dioxide gas to obtain 104 g of an adsorbent. The specific surface area of the prepared adsorbent was 440 m 2 / g, and the pore volume was 0.34 cc / g.

Example 4

In the same manner as in Example 3, the prepared 242 g of solid carbide was rotated at a rate of 10 rpm per minute in a batch rotary furnace and activated with carbon dioxide gas at 1,000 ° C. for 1 hour to obtain 84 g of soil modifier. The specific surface area of the prepared adsorbent was 290 m 2 / g, and the pore volume was 0.23 cc / g.

Example 5

In the same manner as in Example 3, 242 g of the solid carbide prepared above was activated at 900 ° C. for 1 hour while rotating at a speed of 10 rpm per minute in a batch rotary furnace to obtain 177 g of a soil improver. The specific surface area of the prepared adsorbent was 250 m 2 / g, and the pore volume was 0.20 cc / g.

The physical properties of the density, specific surface area, and pore volume of the adsorbents prepared in Examples 1 to 5 are summarized in Table 1 below.

division Density (g / cc) Specific surface area (㎡ / g) Pore Volume (cc / g) Example 1 0.43 415 0.31 Example 2 0.40 430 0.33 Example 3 0.41 440 0.34 Example 4 0.31 290 0.23 Example 5 0.45 250 0.20

As described above, the pyrolysis residue obtained by pyrolyzing waste polystyrene as waste according to the present invention is effectively recycled as an adsorbent raw material to reduce the environmental pollution problem caused by waste, and also in terms of economics such as securing a stable adsorbent raw material and reducing production cost. There is an advantage that it is good, the utility is expected.

Claims (5)

Putting the waste polystyrene melt into a pyrolysis reactor and pyrolyzing in the range of 350 to 400 ° C. to prepare a styrene monomer and a pyrolysis residue; The prepared pyrolysis residue is heated in an inert atmosphere in the range of 900 to 1000 ° C. to separate and recover the volatile component and the solid carbide; And Method for producing an adsorbent, characterized in that three steps by performing the activation reaction in the solid carbide with the oxidizing gas in the range 900 ~ 1000 ℃. The method of claim 1, wherein the one-step melting is injection molding in the range of 220 ~ 280 ℃. The method of claim 1, wherein the pyrolysis residue contains 75 to 85% by weight of carbon, has a softening point of 250 to 350 ° C, and a toluene insoluble content in the range of 60 to 90% by weight. The method of claim 1, wherein the activation reaction is carried out for 0.5 to 3 hours. The method of claim 1, wherein the adsorbent has a specific surface area in the range of 250 to 450 m 2 / g and a pore volume in the range of 0.18 to 0.35 cc / g.

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