Polystyrene transformation by thermal and catalytic pyrolysis

L. PIERELLA, M. RENZINI, D.CAYUELA.

Taiwan

Conferencia; Southeast Asia Environmental Forensics Conference; 2005

Abstract Catalytic transformation of waste polymers into hydrocarbons with higher commercial value shows a great interest. Polystyrene (PS) was transformed mainly to liquid hydrocarbons (LHC = >94.96 wt %), by thermal degradation and catalytic cracking over MEL modified zeolites, H-ZSM-11 and Zn-ZSM-11. The conversion levels were nearly complete between 400-500oC. The main LHC products of PS catalytic degradation were benzene and styrene, and in minor proportion indanes and α-methylstyrene, being these compounds very important in the polymers technology and petrochemical field. Styrene was the most important product in the thermal cracking. A single-pass reactor and atmospheric pressure was employed. The crystallinity, the nature of the structure and the stability of the synthesized and modified catalysts after cation incorporation were confirmed by XRD, FTIR and surface area by BET.  The nature of acidic sites was determined by FTIR of pyridine adsorbed. The reactant (atactic PS) was characterized by TG-DSC. Reaction products were analyzed by gas chromatography and mass spectrometry.  By means of the development of a competitive catalytic system, we determine the feasibility of the process of degradation of PS  towards the synthesis of LHC products.