Depolymerization of fluoropolymers

US8212091B2 · kind B2 · utility

Assignee

• The South African Nuclear Energy Corporation Limited · ZA

Inventors

• Izak Jacobus Van Der Walt · Krugersdorp, ZA
• Alfred Teo Grunenberg · Krugersdorp, ZA
• Johannes Theodorus Nel · Kempton Park, ZA

Key dates

• Filing date: Nov 24, 2006
• Grant date: Jul 3, 2012
• Expiry date: Jan 11, 2029

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02W30/62
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

A process for depolymerizing fluoropolymers includes continuously feeding a solid fluoropolymer, in particulate form, into a horizontal cylindrical first reaction zone. The fluoropolymer particles enter the first reaction zone at one end. Within the first reaction zone, a central axle from which protrudes at least one paddle, continuously rotates. The rotating paddle serves to advance the fluoropolymer particles along the reaction zone while agitating them. As the fluoropolymer particles pass along the reaction zone, they are subjected to an elevated temperature, thereby depolymerizing the fluoropolymer into a fluoro-containing compound-rich gas phase. A residual solids phase is withdrawn at the other end of the first reaction zone, as is the gas phase. Optionally, the gas phase is passed through a second reaction zone which is also at an elevated temperature. The gas phase is quenched, thereby to recover the fluoro-containing compounds as gaseous products.