Abstract
Light cycle oil (LCO) is an inexpensive feedstock for the production of high-added-commercial-value-mono-aromatic compounds such as benzene, toluene and xylenes (BTX). To extend the knowledge on the processing of LCO for BTX production, the hydrocracking reaction was studied using a commercial NiMo/Al2O3 catalyst, ZSM-5 zeolite and their mechanical mixtures (20/80, 30/70 and 50/50) for processing tetralin as model feedstock in a bench-scale-trickle-bed reactor at 450–500 °C, 3.9–5.9 MPa, 1.3 1/h and H2/feed volume ratio of 168–267 m3/m3. Accessible, well-dispersed and strong Brönsted acid sites eased the hydrocracking of tetralin to BTX and the metallic hydrogenation functions from nickel–molybdenum catalysts were also required to minimize deactivation. To achieve suitable tetralin conversions (86–95 wt%), high BTX selectivity in the liquid phase (44–70 wt%) and suitable catalytic activities for coke precursor hydrogenation (to reduce deactivation), NiMo/Al2O3//ZSM-5 mixtures (50–80 ZSM-5) were employed, which probed to be effective.
Highlights
C22 C23 C24 i-C14 C14Development involves hydrogenation (HYD) and hydrocracking (HYC) transformations (Fig. 2, with naphthalene as a model molecule) [15]
The increasing development of more environmentally friendly energy sources like those provided by the sun, hydrogen and biofuels has exerted a negative impact on the global demand for oil and natural gas for fuel manufacture,1 3 Vol.:(0123456789) Area, %Applied Petrochemical Research (2019) 9:185–198Tri-methyl-naphthalenes C17 Tetra-methyl-naphthalenesPhenanthrenes i-C162-Methyl-naphthalenes 1-Methyl-naphthaleneDimethyl-naphthalenes 2.5 i-C15 C16 i-C17 i-C18 C18 i-C19
These scientists concluded that a suitable catalyst for a 54.3% BTX yield from tetralin could be synthesized by supporting nickel and molybdenum on a mechanical mixture of Beta and HZSM-5 zeolites with a 90/10 ratio when reacting at 425 °C
Summary
Development involves hydrogenation (HYD) and hydrocracking (HYC) transformations (Fig. 2, with naphthalene as a model molecule) [15]. Shin et al [20] studied the design of a catalyst with the appropriate balance of hydrogenation and acidity characteristics for producing BTX from polycyclic aromatics present in diesel-boiling-range feedstocks like LCO These scientists concluded that a suitable catalyst for a 54.3% BTX yield (theoretical maximum of 67.1%) from tetralin could be synthesized by supporting nickel and molybdenum on a mechanical mixture of Beta and HZSM-5 zeolites with a 90/10 ratio when reacting at 425 °C. The hydrogenation capabilities of a metallic catalyst (NiMo/Al2O3) combined with the acidic function of a zeolitic material (ZSM-5) were used to study the tetralin hydrocracking for BTX production, focusing on the compromise between BTX selectivity and catalyst deactivation. The feed was run continuously for 24 h; gas and liquid reaction products were collected every 8 h and analyzed according to the methods described and the obtained average values were used to estimate the catalytic performance for a given experimental point. The yields of coke precursors (Yc) were calculated considering the weight of polymerized carbon (Wc, Sect. 2.1) and the total feed weight (Wf) after 144 h of TOS to facilitate comparisons: Yc
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