Different approaches to convert waste polyolefins into automotive fuels via hydrocracking with a NiW/HY catalyst

Hydrocracking Mechanisms of Oxygenated Plastics and Vacuum Gasoil Blends

“…Regardless of the feedstock, we observe a shift towards higher temperatures in the derivative thermogravimetric distributions at 420 °C, showcasing the more aromatic and condensed nature of the coke formed at higher hydroprocessing temperatures [50]. This result is supported by the well-established effect of temperature on the dehydrogenation of coke formation promoters [15]. As cracking reactions are promoted by temperature, the resulting dienes from the cracking of the large hydrocarbons in VGO can be converted into saturated species or oligomers that evolve as coke precursors [51].…”

“…Specifically, when feeding VGO, we detect higher amounts of naphthenes and monoaromatics that result from boosting the hydrocracking of LCO and HCO fractions of the feedstock. The decreased concentration of diaromatics at 420 °C (from 3.5 wt% at 400 °C to 0.1 wt% at this temperature) indicates the displacement of the thermodynamic limitation for aromatic hydrogenation [15]. Conversely, PMMA/VGO and PET/VGO products seem more affected by this limitation, as both mono-and di-aromatic concentrations increases, even if the conversion of both plastics and VGO rises in both cases.…”

“…Hydroprocessing units are recognized as versatile and capable of co-processing wastes of different origins as secondary refinery streams [10,11], biomass-derived liquids [12,13], products of a previous pyrolysis stage [14,15] or even waste in a straight run [16,17] together with conventional refinery streams. Due to the nature of the process, hydroprocessing has the advantage of providing products that do not require subsequent This preprint research paper has not been peer reviewed.…”

A six-lump kinetic model for HDPE/VGO blend hydrocracking

“…The other properties of the VGO are also summarized in Table S1 in the Supplementary Material. A detailed explanation of the methods and procedures followed for characterizing the VGO can be found elsewhere [35]. Shortly, it is a refinery stream with a density of 0.89 g cm − 3 and a boiling point range of 314-519 • C.…”

Thermochemical recycling of end-of-life and virgin HDPE: A pilot-scale study

“…For instance, moderate temperatures during HDPE pyrolysis (less than 500 ºC) lead significantly to high molecular weight hydrocarbon products in the wax range (C 21+ ) [27][28][29]. Further increasing the pyrolysis temperature intensifies the mono-and bi-molecular reactions [27,30,31] and decreases the final product molecular weight [32][33][34]. Bimolecular reactions such as Diels-Alder result in the formation of naphthenes, aromatics, and polyaromatics (coke) [35][36][37].…”