RU2262520C1 - Method for processing organic polymeric waste - Google Patents

Abstract

FIELD: polymers, chemical technology.

SUBSTANCE: invention relates to a method for processing organic polymeric waste to motor fuel and chemical raw that can be used in organic and petroleum chemical synthesis. Invention describes a method for processing organic polymeric waste involving fluidizing polymers, mixing with catalyst and thermocatalytic destruction of reaction mixture. Fluidizing waste is carried out in alkylbenzene medium at 140-150°C under normal atmosphere pressure followed by stirring with clay modified by acid treatment as a catalyst in the mass ratio waste to catalyst = (1-2):1. Drying is carried out at the room temperature and thermocatalytic destruction is carried out in reactor of flow-type in inert gas flow at temperature 350-400°C under normal atmosphere pressure. Method provides simplifying technology, to reduce energy consumption and to use inexpensive available materials as a catalyst.

EFFECT: improved processing method.

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Description

The invention relates to the chemical processing of polymer waste into motor fuel and chemical raw materials, which can be further used in organic and petrochemical synthesis.

As a result of the constant increase in the volumes of industrial and domestic organic polymer wastes, the problem of their recycling is currently very urgent. The most promising methods are chemical processing in order to obtain high-quality motor fuel and raw materials for organic and petrochemical synthesis.

A known processing method, which includes grinding secondary polyethylene, fractionation in a boiling solvent into soluble sol and insoluble gel fractions with separation and washing of fractionation products and low-temperature pyrolysis in vacuum separately for each fraction (patent RU No. 2106365, C 08 J 11/04 publ. 03/10/98).

The disadvantage of this method is its multi-stage, which complicates the process. The method allows to obtain a limited set of products, mainly heavy hydrocarbon fractions.

There is also known a method of processing polymers to produce heavy hydrocarbon fractions (for example, bitumen), which consists in the thermocatalytic decomposition of polymers in the presence of an acid type catalyst, which can be used as a copper-containing or aluminosilicate mineral (US Patent No. 6043289, C 08 J 11/10, publ. . March 28, 2000). The disadvantage of this method is the lack of light hydrocarbon fractions among the products.

A known method of processing organic industrial and household polymer waste into motor fuel and chemical raw materials, including thermal liquefaction of waste in alkylbenzene at a temperature of 270 - 420 ° C and high pressure up to 6 MPa in the presence of a rare earth metal or intermetallic compounds based on rare earth metals, or in the presence of titanium hydride taken in an amount of 0.5-10% by weight of the reaction mixture (Patent RU No. 2110535, C 08 J 11/04, publ. 10.05.98).

The advantage of this method is the possibility of using the crude benzene distillation product obtained as a result of high-temperature coking of fossil fuels as a solvent. A significant limitation of the method lies in the need to use expensive rare earth metals as a catalyst, as well as increased pressure, which increases the cost of the process.

A known method of processing organic waste into motor and chemical raw materials, in which the waste is heat-liquefied at a temperature above 270 ° C and at an increased pressure of 6.1 MPa by dissolving in alkyl benzene, separating the liquid fraction and its distillation (Patent RU No. 2167168, C 08 J 11/04, publ. 05.20.98).

The advantage of this method is the relatively low solvent consumption due to the return of part of the reaction mixture to the solution as a solvent. The disadvantage of this method is the need to maintain a high pressure exceeding atmospheric 6 times.

The closest in technical essence to the proposed is a method of processing polymer waste, which consists in mixing plastic waste with catalyst particles in an amount of 5-10% of plastic waste, thermo-liquefying the waste mixture with the catalyst by melting and subsequent thermocatalytic destruction in the temperature range 440-470 ° C using as a catalyst systems such as alumina - iron oxide, silicon oxide - iron oxide and zeolites (US Patent No. 4584421, publ. 04/22/1986).

The advantages of this method include a low yield of coke. The disadvantages of the method are the need to carry out the process at a high temperature (above 440 ° C) and the technically difficult stage of thermal fluidization of the polymers, since in the presence of air the target process of thermal fluidization is inevitably accompanied by the oxidation of the polymers to carbon dioxide and water.

The objective of the invention is to expand the arsenal of existing methods of processing polymer waste by creating a method of processing polymer waste using affordable and inexpensive raw materials for the preparation of catalysts, with a simplified technology of thermal fluidization and preventing polymer loss due to oxidative degradation.

The problem is solved by a method consisting in thermal fluidization of polymers and subsequent thermocatalytic destruction, in which, unlike the prototype:

- liquefaction of the polymer is carried out in an environment of alkylbenzene, for example in xylene, in a mass ratio of xylene: polymer (3-5): 1 at a temperature of 140-150 ° C and normal atmospheric pressure,

- the catalyst is introduced by mixing with the liquefied polymer in a mass ratio polymer: catalyst equal to (1-2): 1;

- the crushed clay modified by acid treatment is used as a catalyst;

- the mixture is dried at room temperature;

- subsequent thermocatalytic destruction of the hardened mixture of polymer and catalyst is carried out in a flow-type reactor in an inert gas stream at a temperature of 350-400 ° C and normal atmospheric pressure.

Comparative analysis with known technical solutions shows that the claimed method meets the criterion of "novelty" according to the following criteria.

Thermal liquefaction of the crushed polymer is carried out in a solvent of a number of alkylbenzenes, for example xylene, at a temperature of 140-150 ° C and normal atmospheric pressure, the mixture of polymer and catalyst is dried at room temperature, the catalytic decomposition of the solidified polymer and catalyst mixture is carried out in an argon stream in a flow reactor at temperature 350-400 ° C and normal atmospheric pressure.

The claimed technical solution meets the criterion of "inventive step", as it allows to obtain liquid products of light hydrocarbon fractions, in particular motor fuel with a high octane rating, and products suitable for use in organic and petrochemical synthesis, by using the proposed technical solution, including such features as thermal liquefaction at a temperature of 140-150 ° C and normal atmospheric pressure, drying a mixture of polymer and catalyst at room temperature and thermocatalytic some decomposition of the polymer mixture and the catalyst at atmospheric pressure at a temperature not lower than 350 ° C.

The proposed method does not require the use of high pressure and high temperatures inherent in the known methods, which allows to reduce energy consumption.

An example implementation of the method.

To obtain the reaction mixture, the polymer is pre-crushed and transferred to a soluble state at a temperature of 140-150 ° C, using xylene as a solvent, in a xylene: polymer weight ratio of 3: 1. In the obtained polymer solution, without cooling, the crushed catalyst is placed in the mass ratios polymer: catalyst (1-2): 1. Then the resulting suspension is dried at room temperature, the solidified mixture is loaded into a flow-type reactor. The temperature is raised to 350-400 ° C and the mixture is isothermally maintained at normal atmospheric pressure in an inert gas flow until the end of the selection of products. Destruction products are collected and condensed in a cooled receiver.

The composition of the products was studied by gas-liquid chromatography (GLC). The octane number of the gasoline fraction was evaluated by a research method.

When the destruction of polyethylene by the proposed method can be obtained a mixture of more than 100 different hydrocarbons With ₅ - With ₃₁ . The gasoline fraction accounts for at least 25% of the mass of liquid products.

Example. Waste polyethylene weighing 2 g was dissolved in a mixture of xylene isomers weighing 6 g during boiling. 2 clays pretreated with sulfuric acid were added to the liquefied polymer. The mixture was dried at room temperature. A portion of the mixture of polyethylene and catalyst was placed in a flow reactor. The destruction process was carried out until the end of the separation of products at 400 ° C in an argon flow. At the outlet of the reactor, a receiver equipped with a reflux condenser was installed to collect liquid products.

The octane number of the gasoline fraction (according to the research method) was 79. The group composition of the gasoline fraction is presented in the table.

Table
The group composition of the gasoline fraction (t _boiling <180 ° C) of liquid products of thermocatalytic destruction of polyethylene Group The content of degradation products, wt.% n-alkanes 3.2 iso alkanes 52.9 arenas 15.1 naphthenes 18.6 olefins 10.0

Claims (1)

A method of processing organic polymer waste, including liquefaction of polymers, mixing with a catalyst and thermocatalytic destruction of the reaction mixture, characterized in that the liquefaction of the waste is carried out in an environment of alkylbenzene at 140-150 ° C and normal atmospheric pressure, followed by mixing with a catalyst - modified acid treatment with clay - when the mass ratio of waste and catalyst is 1-2: 1, drying is carried out at room temperature, and thermocatalytic destruction is carried out in a flow type reactor in a stream mercury gas at a temperature of 350-400 ° C and normal atmospheric pressure.