TY - JOUR
T1 - Insights into the coke deposited on HZSM-5, Hβ and HY zeolites during the cracking of polyethylene
AU - Castaño, Pedro
AU - Elordi, Gorka
AU - Olazar, Martin
AU - Aguayo, Andres T.
AU - Pawelec, Bárbara
AU - Bilbao, Javier
N1 - Generated from Scopus record by KAUST IRTS on 2019-08-08
PY - 2011/4/27
Y1 - 2011/4/27
N2 - The effect of the zeolite structure (HZSM-5, Hβ and HY) on coke deposition during the cracking of high-density polyethylene has been studied by combining the results of multiple spectroscopic and analytical techniques: FTIR, Raman, UV-vis, 13C NMR and coke extraction, followed by GC-MS and 1H NMR analysis. In addition, by combining FTIR and temperature programmed oxidation (TPO) analysis we obtained information on the coke: properties, burn-off, and changes in composition during catalyst regeneration. Samples of the spent catalysts were obtained in a state-of-the-art pilot plant (conical spouted bed reactor) after the continuous treatment of 900g (1gmin-1, 15h) of high-density polyethylene at 500°C, using 30g of catalyst. The results show that as the pore diameter of the zeolite is increased, bimolecular reactions (hydrogen transfer and oligomerizations), condensations and cyclizations are enhanced, yielding more aromatic coke. Furthermore, the pore topology of the HZSM-5 zeolite improves the flow of coke precursors (also favored by the high flow rate of N2) to the outside of the catalyst; viz. HZSM-5 catalyst preserves its activity for longer. © 2011 Elsevier B.V.
AB - The effect of the zeolite structure (HZSM-5, Hβ and HY) on coke deposition during the cracking of high-density polyethylene has been studied by combining the results of multiple spectroscopic and analytical techniques: FTIR, Raman, UV-vis, 13C NMR and coke extraction, followed by GC-MS and 1H NMR analysis. In addition, by combining FTIR and temperature programmed oxidation (TPO) analysis we obtained information on the coke: properties, burn-off, and changes in composition during catalyst regeneration. Samples of the spent catalysts were obtained in a state-of-the-art pilot plant (conical spouted bed reactor) after the continuous treatment of 900g (1gmin-1, 15h) of high-density polyethylene at 500°C, using 30g of catalyst. The results show that as the pore diameter of the zeolite is increased, bimolecular reactions (hydrogen transfer and oligomerizations), condensations and cyclizations are enhanced, yielding more aromatic coke. Furthermore, the pore topology of the HZSM-5 zeolite improves the flow of coke precursors (also favored by the high flow rate of N2) to the outside of the catalyst; viz. HZSM-5 catalyst preserves its activity for longer. © 2011 Elsevier B.V.
UR - https://linkinghub.elsevier.com/retrieve/pii/S0926337311000944
U2 - 10.1016/j.apcatb.2011.02.024
DO - 10.1016/j.apcatb.2011.02.024
M3 - Article
SN - 0926-3373
VL - 104
JO - Applied Catalysis B: Environmental
JF - Applied Catalysis B: Environmental
IS - 1-2
ER -