Catalytic Aromatization of Rapid Pyrolysis Gas of Low-density Polyethylene Using a Tandem Reactor

Catalytic conversion of LDPE (low-density polyethylene) pyrolysis gas into valuable products was investigated to promote recycling of plastics. LDPE pyrolysis and catalytic conversion using a tandem reactor showed the potential for selective recovery of aromatics. LDPE was rapidly pyrolyzed at high temperatures in the first reactor, yielding uniform product in the pyrolysis. The zeolite catalyst in the second reactor of the LDPE pyrolysis effectively decomposed heavy hydrocarbons and formed aromatics. In particular, Beta-type zeolite and MFItype zeolite showed relatively high aromatics yields, whereas Na-exchanged zeolite did not show decomposition activity. The results indicated the importance of strong Br & oslash;nsted acid sites for aromatics production. Furthermore, LDPE pyrolysis within the system required higher temperatures than the decomposition temperature of LDPE, highlighting the necessity for rapid pyrolysis to achieve effective catalytic conversion into aromatics. The tandem system consistently showed stable aromatics yields across multiple tests.