Method and apparatus for pyrolytically decomposing waste plastic
US6172275A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1998 |
| Grant date | Jan 9, 2001 |
| Priority date | — |
| Expiry date | Mar 3, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10G1/10
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
Disclosed is a method and apparatus for pyrolytically decomposing waste plastic which may contain halogen-containing polymer such as PVC. The plastic is heated at 270.degree. to 350.degree. C., whereby a plasticizer contained in the plastic material is decomposed and vaporized, and a chlorine-containing polymer is dechlorinated to produce hydrogen chloride. The vaporized decomposition matter and the hydrogen chloride are removed from the plastic, and the vaporized decomposition matter is separated from the hydrogen chloride. Then isolated plastic is further heated to 450.degree. C. or higher to produce a pyrolysis product. Alternatively, the former heating step is divided into two steps of: heating at a temperature lower than 270.degree. C., whereby a plasticizer is decomposed; and heating to 270.degree. to 350.degree. C., whereby a chlorine-containing polymer contained in the plastic material is dechlorinated. Accordingly, the decomposition matter of plasticizer and hydrogen chloride are separately removed from the plastic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.