Polymer waste recycling over fresh, steam deactivated and used FCC catalysts

Abstract

Feedstock recycling of high-density polyethylene (HDPE) over fluid catalytic cracking (FCC) catalysts (6:1 ratio) was carried out using a laboratory fluidised bed reactor operating at 450oC, atmospheric pressure and nitrogen environment. Fresh and steam deactivated commercial FCC catalysts with different levels of rare earth oxide (REO) were compared as well as used FCC catalysts (E-Cats) with different levels of metal poisoning. The initial activity of the catalysts was also estimated by hexane cracking in a fixed bed reactor at 450oC. The results of HDPE degradation, in terms of yield of volatile hydrocarbon product, were: Fresh FCC catalysts > steamed FCC catalysts ≈ used FCC catalysts. Overall, the product yields from HDPE cracking showed that the level of metal contamination (nickel and vanadium) did not affect the product stream generated from polymer cracking. The promising results of this study help to establish a more economic catalytic alternative for polymer waste recycling.