A device for reducing the volume of waste plastics by removing chlorine and a method for reducing the volume of waste plastics by removing chlorine

Abstract

This invention provides a waste plastic volume reduction and dechlorination apparatus and method that achieves high production efficiency and reduces equipment and operating costs through appropriate distribution of dechlorination treatment in high-temperature ranges. [Solution] The present invention comprises: a) an optical sorting device for separating waste plastic Po into chlorine-containing waste plastic Pc and non-chlorine waste plastic Pf; b1) a first volume reduction extrusion device for reducing the volume of chlorine-containing waste plastic Pc while heating it to 120-200°C and removing moisture by vaporization; b2) a dechlorination extrusion device for discharging dechlorinated waste plastic Pd from the volume-reduced chlorine-containing waste plastic Pc while separating HCl gas by heating it to 250-400°C; and c) a second volume reduction extrusion device for reducing the volume of non-chlorine waste plastic Pf while heating it to 120-200°C and removing moisture by vaporization.

Claims

1. A waste plastic volume reduction and dechlorination apparatus that reduces the volume of waste plastic Po containing multiple types of materials, including chlorine-based polymers, while dechlorinating it, in order to obtain a waste plastic aggregate that is substantially free of chlorine-based polymers, (a) An optical sorting device that sorts the waste plastic Po supplied in a state crushed to a predetermined size into chlorine-containing waste plastic Pc containing chlorine polymers and non-chlorine waste plastic Pf substantially free of chlorine polymers, based on differences in wavelength absorption depending on the material, (b1) A first volume reduction extruder that reduces the volume of the chlorine-containing waste plastic Pc by raising the resin temperature to 120°C or higher and 200°C or lower, while removing moisture as water vapor, thereby obtaining a volume-reduced product. (b2) A dechlorination extruder that separates chlorine from the volume-reduced chlorine-containing waste plastic Pc as hydrogen chloride gas and exhausts it while raising the resin temperature to 250°C or higher and 400°C or lower, and discharges dechlorinated waste plastic Pd that is substantially free of chlorine-based polymers, (c) A second volume reduction extruder that reduces the volume of the non-chlorine waste plastic Pf by raising the resin temperature to 120°C or higher and 200°C or lower, while removing moisture as water vapor, thereby obtaining a volume-reduced product. A waste plastic volume reduction and dechlorination device.

2. (a1) The waste plastic volume reduction and dechlorination apparatus according to claim 1, further comprising one or more additional optical sorting devices along the conveying direction of the chlorine-containing waste plastic Pc.

3. (a2) The waste plastic volume reduction and dechlorination apparatus according to claim 1, further comprising one or more additional optical sorting devices along the transport direction of the non-chlorinated waste plastic Pf.

4. A method for reducing the volume and dechlorinating waste plastics, comprising dechlorinating waste plastics containing multiple types of materials including chlorine-based polymers, to obtain aggregates of waste plastics that are substantially free of chlorine-based polymers, (a) An optical sorting step in which the waste plastic Po supplied in a state crushed to a predetermined size is sorted by an optical sorting device into chlorine-containing waste plastic Pc containing chlorine polymers and non-chlorine waste plastic Pf substantially free of chlorine polymers, based on the difference in wavelength absorption depending on the material, (b1) A first volume reduction step in which the chlorine-containing waste plastic Pc is heated in a volume reduction extruder to a resin temperature of 120°C or higher and 200°C or lower, and the volume is reduced while removing moisture as water vapor to obtain a volume-reduced product, (b2) A dechlorination process in which, from the volume-reduced chlorine-containing waste plastic Pc, chlorine is separated as hydrogen chloride gas and exhausted using a dechlorination extruder while raising the resin temperature to 250°C or higher and 400°C or lower, and dechlorinated waste plastic Pd which is substantially free of chlorine-based polymers is discharged, (c) A second volume reduction step in which the non-chlorine waste plastic Pf is heated in a volume reduction extruder to a resin temperature of 120°C or higher and 200°C or lower, thereby reducing its volume while removing moisture as water vapor, thereby obtaining a volume-reduced product. A method for reducing the volume of waste plastics and removing chlorine.

5. (a1) The optical sorting process is repeated one or more times along the transport direction of the chlorine-containing waste plastic Pc. The method for reducing the volume of waste plastics and removing chlorine according to claim 4, wherein the sorting accuracy of chlorine-containing waste plastics Pc from waste plastics Po is increased according to the number of repetitions of the optical sorting step.

6. (a2) The optical sorting process is repeated one or more times along the transport direction of the non-chlorine waste plastic Pf. The method for reducing the volume of waste plastics and removing chlorine according to claim 4, wherein the sorting accuracy of the non-chlorine waste plastic Pf from the waste plastic Po is increased according to the number of repetitions of the optical sorting step.

7. A method for reducing the volume of waste plastics by dechlorinating them according to any one of claims 4 to 6, wherein the operating conditions of the optical sorting step and the dechlorination step are adjusted so that the chlorine content of the waste plastics, when the non-chlorinated waste plastic Pf and the dechlorinated waste plastic Pd are combined, is less than 1.0% by mass.

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