Catalytic degradation of high density polyethylene and polypropylene into liquid fuel in a powder-particle fluidized bed

Abstract

Catalytic degradation of high density polyethylene (HDPE) and polypropylene (PP) were carried out in this work in a powder-particle fluidized bed with inside diameter of 25 mm. Two kinds of catalysts (F9; Silica/Alumina,SA) were used as medium particles fluidized by nitrogen. The yields of liquid fuel, gas product and solid residue were investigated under different operating conditions, including catalyst type, bed temperature, superficial gas velocity. The compositions of liquid and gas products were also determined by gas chromatography. Between two kinds of catalyst, SA can produce higher yield of liquid fuel and more valuable gas product under temperature range from 400 to 550°C. Over 86 wt.% conversion of liquid fuel, containing hydrocarbons from C-5 to C-11, was reached from both HDPE and PP under 500°C with a residue yield level of less than 8 wt.%. Gas product under appropriate operating conditions contains over 59 wt.% ethylene and propylene.