Two-stage vacuum hot chemical treating and recovering process and apparatus for halogen-containing waste plastic

A technology for thermochemical treatment and waste plastics, which is applied in the field of two-stage vacuum thermochemical treatment and recovery devices for halogen-containing waste plastics. It can solve the problems of high halogen content, high cost, and inability to regenerate, so as to achieve complete separation of halogens and increase volatility. , the effect of reducing the number

Inactive Publication Date: 2006-08-02
SOUTH CHINA UNIV OF TECH
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AI Technical Summary

Problems solved by technology

If incineration is used to recover energy, the halogens in the flame retardants may form highly toxic carcinogens such as dioxins and furans during combustion. At the same time of pyrolysis, various halogenated organic small molecular compounds are mixed in the pyrolysis oil, which makes the further utilization of pyrolysis oil difficult
From the perspective of the structure of halogenated flame retardants, the chlorine atoms and bromine atoms in the halogenated flame retardant molecules are mainly connected to the aromatic carbon atoms of the flame retardant molecules, and their bond energy is higher than that of carbon in polyvinyl chloride (PVC). - The chlorine bond energy is large, and the carbon-halogen bond breaking temperature is closer to the carbon-carbon bond breaking temperature. Therefore, the halogen-containing pyrolysis products of flame retardants are mainly various organic halogenated substances, unlike PVC, which is dominated by hydrogen halides. These halogenated Substitutes cannot be easily separated from the plastic melt like hydrogen chloride, so the existing PVC two-stage pyrolytic dehydrochlorination process is not suitable for pyrolytic dehalogenation of halogen-containing flame-retardant plastics
[0004] "Journal of Material Cycles and Waste Management" 2003 No. 5, pages 113 to 124, discloses a catalytic pyrolysis process of halog

Method used

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  • Two-stage vacuum hot chemical treating and recovering process and apparatus for halogen-containing waste plastic

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Experimental program
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Effect test

Embodiment 1

[0028] The main plastic components are HIPS, ABS, PP and PS mixed plastic crushed materials for home appliance shells, and it is found that the main flame retardants are decabromodiphenyl ether, octabromodiphenyl ether, tetrabromobisphenol A, etc., containing bromine 10 %about.

[0029] Crushing and melting the above-mentioned halogen-containing waste plastics to obtain a melt;

[0030] The melt is melted and separated in a vacuum melting and separating tank with a temperature of 250°C and a pressure of 10kpa for 1 hour, and the flame retardant gas and other small molecule gases in the halogen-containing waste plastic melt volatilize; the volatilized flame retardant gas and other The small molecule gas is condensed, and the condensate is collected; the non-condensable gas produced is washed with lye, and then sent to the gas treatment system for treatment; the waste plastic melt after the flame retardant is separated is heated in a vacuum at a temperature of 500°C and a pressu...

Embodiment 2

[0033] The main plastic components are HIPS, ABS, PP and PS. The mixed plastics of the home appliance casing are analyzed and found that the main flame retardants are decabromodiphenyl ether, octabromodiphenyl ether, tetrabromobisphenol A, etc., containing about 10% bromine .

[0034] Crushing and melting the above-mentioned halogen-containing waste plastics to obtain a melt;

[0035] The melt is melted and separated in a vacuum melting and separating tank with a temperature of 350°C and filled with nitrogen atmosphere for 3 hours under normal pressure, and the flame retardant gas and other small molecule gases in the halogen-containing waste plastic melt volatilize; The fuel gas and other small molecular gases are condensed, and the condensate is collected; the non-condensable gas produced is washed with lye and sent to the gas treatment system for treatment; Pyrolysis in a vacuum pyrolysis tank of 5Kpa for 60 minutes.

[0036]The yield of flame retardant liquid was 18.9%, ...

Embodiment 3

[0038] The main plastic components are HIPS, ABS, PP and PS mixed plastic crushed materials for home appliance shells, and it is found that the main flame retardants are decabromodiphenyl ether, octabromodiphenyl ether, tetrabromobisphenol A, etc., containing bromine 10 %about.

[0039] Crushing and melting the above-mentioned halogen-containing waste plastics to obtain a melt;

[0040] The melt is melted and separated in a vacuum melting and separating tank with a temperature of 300°C and a pressure of 5kpa for 2 hours, and the flame retardant gas and other small molecule gases in the halogen-containing waste plastic melt volatilize; the volatilized flame retardant gas and other The small molecular gas is condensed, and the condensate is collected; the non-condensable gas produced is washed with lye and sent to the gas treatment system for treatment; the waste plastic melt after the flame retardant is separated is heated in a vacuum at a temperature of 550 ° C and a pressure ...

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Abstract

The present invention discloses two-stage vacuum heat chemical treating and recovering process and apparatus for halogen containing waste plastic. The process includes melting the waste plastic, separating fire retardant, condensing fire retardant gas, treating un-condensed gas, pyrolysis of waste plastic melt, condensing pyrolysis gas, treating pyrolysis residue and other steps. The apparatus for the treatment includes feeding bin, vacuum melting and separating tank with feeding screw, stirrer, vacuum pyrolysis reactor with feeding screw, fire retardant gas condenser, pyrolyzed oil condenser, gas washing tower, un-condensed gas treating system, vacuum pump, halogen containing fire retardant collecting tank, low halogen pyrolyzed oil collecting tank, pyrolysis residue discharging screw, vacuum sealing valve, pyrolysis residue storage and electric heating system.

Description

technical field [0001] The invention relates to a method for recycling halogen-containing waste plastics, in particular to a two-stage vacuum thermochemical treatment recovery method for halogen-containing waste and old thermoplastics containing additive-type halogen-based flame retardants. [0002] The invention also relates to a two-stage vacuum thermochemical treatment and recovery device for halogen-containing waste plastics. Background technique [0003] With the rapid development of the plastics industry and the electrical and electronic industries in the past ten years, the problem of handling a large number of halogen-containing plastics in waste plastics, especially waste electrical and electronic equipment, is very prominent. In electrical and electronic equipment, halogenated flame retardants are added to many plastic parts for safety reasons. If incineration is used to recover energy, the halogens in the flame retardants may form highly toxic carcinogens such as...

Claims

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Application Information

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IPC IPC(8): C08J11/04B09B3/00C10G1/00
CPCY02P20/143Y02W30/62
Inventor 陈烈强彭绍洪蔡明招钟建军
Owner SOUTH CHINA UNIV OF TECH
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