Selective cracking of light cycle oil to monoaromatics over non-noble bifunctional zeolite-supported Ni and NiW catalysts

Effect of temperature, hydrogen donor, and zeolites on light cycle oil cracking: thermodynamic, experimental, and DFT analyses

“…8(a)). [24][25][26][27][28]37,38 Hence, correlations between crystallite size and zeolite properties (average pore diameter, total acidity, BET surface area, total/micro pore volume) were obtained, revealing that the crystallite size decreased with an increase in these properties, except for ZSM-5 (Fig. S14, ESI †).…”

“…This is due to the formation of stable diaromatics such as naphthalene and its derivatives (Table S2, ESI †), and indicates the need of a catalyst to improve the BTX yield. 27,28 For all feeds, the decrease in BTX yield at higher temperatures is explained by their conversion to lighter fractions such as gaseous products, paraffins, and olens. Overall, the equilibrium BTX yield exhibits the trend: 1MN > 1MN + 9MA > 9MA, which correlates inversely with the proportion of triaromatics (9MA) in the feed.…”

“…† Detailed information about various operational modes and a comprehensive description of the reactor setup are included elsewhere. 27,28 Feed conversion, product selectivity, product yield, and LCO conversion were determined using eqn (S.2), (S.3), (S.4), and (S.5), † respectively, as outlined in Section 1.1 ESI. † Table S1 † provides information on the physicochemical characteristics and composition of the LCO sample and is explained in Section 1.3 ESI.…”

Dominant role of zeolite in coordination between metal and acid sites on an industrial catalyst for tetralin hydrocracking

“…It is widely accepted that the main function of LAS in the hydrocracking of LCO is related to the dehydrogenation of the saturated C-C bond and hydrogen transfer, resulting in the partial hydrogenation and cracking of PAHs. 30 Similarly, in the hydrocracking of tetralin, the carbenium ions formed during the isomerization of tetralin are derived from the dehydrogenation process of tetralin. The hydride species are abstracted by the LAS, followed by fast hydrogen transfer to other feed molecules, which is associated with the direct or indirect generation of methylindane and results in the production of a large amount of naphthalene.…”

“…However, the presence of excess metal sites in hydrocracking catalysts can also promote the dehydrogenation of tetralin and increase the yield of naphthalene. 36 Therefore, the acid sites of NiMo/Al 2 O 3 + USY(50), NiMo/Al 2 O 3 + USY (30), and NiMo/Al 2 O 3 + USY (10) are not enough to consume the hydrogen derived from metal-activated sites when the content of NiMo/Al 2 O 3 exceeds 30% in catalysts, leading to the process of hydrogenation/ dehydrogenation on the metal sites. A conclusion can be drawn that the amount of metal sites in the NiMo/Al 2 O 3 + USY(70) catalyst is just enough to feed all the acid sites with intermediate naphthenic molecules to isomerization and ring opening.…”