Two-Stage Thermal Gasification of Polyethylene

Abstract

Polyethylene pellets have been gasified by two-stage thermal degradation process. The first stage is the conversion of polyethylene to afford liquid products, and the second stage is the gasification process of the liquid hydrocarbons produced by the first-stage.
The distilled oil yield in the first stage was about 87 w t% at 470°C. The maximum gas yield based on the weight of polyethylene in the second gasification stage was 82 wt% at 800°C. The main components of the product gas were ethylene and methane. The optimum space time at 800°C to obtain the gas lighter than C₄ components was 2.6 s. Under these conditions, the ratio of coking was less than 1 wt%.
The two-stage pyrolyses of polyethylene produce high calorie gas efficiently with low cokin g ratio and some aromatic oils containing benzene, toluene and xylene as main components.