Prospects for Obtaining High Quality Fuels from the Hydrocracking of a Hydrotreated Scrap Tires Pyrolysis Oil

Abstract

The hydrocracking of hydrotreated scrap tires pyrolysis oil (HT-STPO) has been studied aiming high-quality refinery blends for alternative automotive fuels. The hydrocracking runs have been carried out with a PtPd/SiO 2 -Al 2 O 3 catalyst in a fixed-bed reactor at 10 440-500 ºC, 65 bar and space time of 0.16 h. The catalyst has been characterized by ICP-AES, N 2 adsorption-desorption isotherms, and tert-butylamine adsorptiondesorption (TPD), while coke has been studied both quantitatively and qualitatively by TG-TPO, FTIR-TPO and Raman spectroscopy. During the first 2 h of reaction and at temperatures above 480 ºC, we have been able to: (1) reach ultra low sulfur levels lower 15 than 15 ppm; (2) remove almost completely of the less interesting fraction -boiling points higher than 250 ºC, named as gasoil fraction-with remaining amounts lower than 1 wt%; (3) with a paraffinic and isoparaffinic content higher that 70 wt%. Catalyst deactivation is due to coke deposition having both aromatic and aliphatic nature, while the aromaticity increases with process temperature. It has been proved that the 20 temperature conditions can be tuned to reach a state in which coke is generated at the same rate that is being hydrocracked.

Characterization and controlled combustion of carbonaceous deactivating species deposited on an activated carbon-based catalyst

“…The evolution of the product yields with time on stream is detailed in a previous work [20]. A similar effect with temperature was reported by Hita et al [35] for the same process using a Pt-Pd/SiO 2 -Al 2 O 3 catalyst in the 440-500°C range. In that case, a decrease of 40 % of the initial activity was observed at 440°C.…”

“…The existence of phosphate groups on the fresh catalyst surface resulting from the chemical activation with H 3 PO 4 is proven by the P:O ratio measured through XPS [36]. This P-containing groups, with acidic character, provide the catalyst with a total acidity comparable to that of a silica-alumina support [35]. Regarding deactivated catalysts, a remarkable drop of surface area (ca.…”

Revealing the pathways of catalyst deactivation by coke during the hydrodeoxygenation of raw bio-oil

“…One of the main drawbacks of this reaction is the catalyst deactivation due to the formation of carbonaceous deposits (coke), which also causes operational difficulties [23][24][25][26][27][28]. This formation of coke is related to the thermal instability and repolymerization of the phenolic components of bio-oil.…”

A Data-Driven Reaction Network for the Fluid Catalytic Cracking of Waste Feeds

“…Lovás et al [20] compared the catalytic cracking in FCC conditions of high-density polyethylene (HDPE) and polypropylene (PP) waxes together with VGO and it was concluded that PP should be used preferentially in order to boost gasoline production. On the other hand, the condensed pyrolysis oil derived from waste (scrap) tires also shows great prospects to become a FCC feed and produce high quality fuels [21][22][23]. Concerning oxygenated bio-derived streams (iii), a great research interest has been directed towards exploring the possibilities of bio-derived feedstock (i.e., bio-oil and vegetable oils) for FCC conversion [24][25][26][27][28][29][30].…”