Liquid fuel from waste polyolefins part I: Thermal and pressure degradation of waste polyolefins in tetralin as H-donor model system

Abstract

In the paper, the results of the study on a laboratory process of thermal and pressure destruction of waste polyolefins in the presence of tetralin as a model hydrogen donor are presented. Waste polyolefins were termally cracked in the presence of a catalyst and hydrogen donor (tetralin) in a closed autoclave (volume: 1 dm 3) in the anaerobic atmosphere. The process temperature was maintained 400–500 °C. The pressure at the end of process, depending on the feed composition, was 10–15 MPa. As a result, a desirable liquid fraction was obtained. A product of waste polyolefin decomposition in the presence of tetralin is a complex mixture of hydrocarbons. The analysis of products has shown satisfactory decomposition of polymer chains as well as hydrogenation of unsaturated structures. Low sulphur and chlorine contents in the obtained fractions constitute a highly positive effect, especially in a fuel aspect. A significant disadvantage here is a considerable number of tetralin conversion reactions. The use of this hydrogen donor for technological purposes is not possible as the final fraction must be cleared from disproportionation products or hydrogen donor decomposition products.