ANALYSIS OF THE PRODUCTS OBTAINED IN THERMAL AND CATALYTIC DECOMPOSITION OF PLASTIC WASTES

摘要

The objective of this work is the study of pyrolysis as a feedstock recycling process for valorising plastic mixture streams which nowadays have not an industrial recycling alternative. A representative sample of these real streams has been pyrolysed under nitrogen in a 3,5 dm3 reactor at 500 °C for 30 minutes both thermally and with two catalysts, a commercial zeolite HZSM-5 and Red Mud, in order to analyse the influence of catalysts in the products obtained. The liquids obtained in pyrolysis are a complex mixture of organic compounds containing valuable chemicals such as styrene, ethyl-benzene, toluene, etc. Pyrolysis gases are mainly composed of hydrocarbons together with some CO and CO2 and have very high gross calorific values (GCV). Almost no solids are obtained in the pyrolysis of the plastic mixture studied in this work. The presence of catalysts plays a significant role in both pyrolysis yields and products quality. HZSM-5 promotes gas production, produces more aromatic and of lower molecular weight liquids and more H2 in the gases. Red Mud has similar effects but less pronounced than the commercial zeolite.