Stability of ZSM-11 and BETA zeolites during the catalytic cracking of low density polyethylene

MARÍA S. RENZINI; LAURA C. LERICI; ULISES SEDRÁN; LILIANA B. PIERELLA

JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS

ELSEVIER SCIENCE BV

Año: 2011 vol. 92 p. 450 - 455

0165-2370

The stability of H-ZSM-11 (H-Z) and H-BETA (H-B) zeolites during the catalytic degradation of LDPE has been studied using the same sample of catalyst in once consecutive cycles. The gaseous hydrocarbons, liquid hydrocarbons and waxes generated in each cycle were analyzed as well as the used catalyst obtained. The zeolites were characterized by XRD, FTIR of adsorbed pyridine and N2 adsorption; while the physical mixtures LDPE/zeolites were analized by TG-DTG. The H-Z zeolite exhibited an important stability during the successive cycles of LDPE conversion. On the contrary, the behavior H-B zeolite was completely different. From the sixth cycle the yields of products changed progressively, approaching to that obtained in a thermal process. The yields of accumulate coke increased steadily throughout the cycles up to a maximum value in the eleven cycle of ~ 6  and ~ 15 wt% for H-Z and H-B, respectively. These results were confirmed by TG under air flow.