Towards waste refinery: Co-feeding HDPE pyrolysis waxes with VGO into the catalytic cracking unit

The co-feeding of high-density polyethylene pyrolysis waxes (HDPE waxes) with vacuum gasoil (VGO) on the catalytic cracking has been investigated. Runs have been conducted by feeding a blend of HDPE waxes/VGO (1/4 in mass) to a laboratory-scale reactor that mimics the behavior of the riser reactor of the industrial FCC unit. Tested operating conditions have been the following: 500-560 degrees C; catalyst to oil mass ratio (C/O), 3-7 g(cat) g(feed)(-1); and, contact time, 6 s. The comparison of obtained results, i.e., yield and composition of the fractions, in the cracking of the blend with those obtained in the cracking of the VGO and HDPE waxes separately, has exposed the existence of synergetic mechanisms. This way, the cracking of the blend produces a more olefinic gaseous fraction and a naphtha with higher content of iso-paraffins and olefins and lower of aromatics, together with a comparable yield of coke.