Catalytic flash pyrolysis of HDPE in a fluidized bed reactor for recovery of fuel-like hydrocarbons

Products obtained in the flash pyrolysis of HDPE in a fluidized bed reactor, in thermal and catalytic conditions (HZSM-5 or RUSY 20% by weight) at four different temperatures (in the range 500-800 degrees C) have been analyzed in this work focusing on the liquid fraction. The results obtained showed significant differences between condensable compounds generated in presence and absence of catalysts. The liquid fraction obtained without catalyst was composed principally by linear paraffins (C-10-C-40) and almost no generation of aromatic compounds was observed. The presence of low amounts of zeolite (HZSM-5 or HUSY) led to a significant reduction of the saturated and unsaturated condensable hydrocarbons, while it favored the formation of aromatics and branched paraffins. Compared with the results reached with HZSM-5 zeolite, HUSY produces higher amount of aromatics and branched alkanes and a narrower distribution. of products, independently of the pyrolysis temperature. The reactor employed in this work was a fluidized bed reactor, very similar to that used in generation of gasoline-range hydrocarbons at large scale, which allows to illustrate a very useful method for the recovery of these hydrocarbons. (c) 2006 Elsevier B.V. All rights reserved.