Hydrocracking of n‐heptane with a NiO‐MoO₃/HYUS zeolite as catalyst. Kinetic study

Abstract

The hydrocracking of n‐heptane has been carried out in a fixed bed reactor at 2.45 MPa pressure and with a H2/n‐heptane molar ratio of 5.0 using a 4 wt% NiO ‐ 8 wt% MO3/HYUS zeolite as a catalyst. The W/F10 ratio was varied between 75.3 and 1624 kg · s/kmol at different reaction temperatures: 573, 588, 603 and 623 K. The kinetics of the reaction has been studied by two different procedures due to the slight deactivation of the catalyst. One of them uses the conversion and yield values extrapolated at time on stream to zero and the other uses a kinetic equation where the deactivation of the catalyst has been included. The experimental data were fit well by a pseudo‐first order kinetic equation and the kinetic constant values obtained by both methods coincide. The apparent activation energy of the reaction has a value of 105.8 + 5.0 kJ/mol.

Hydrocracking of Athabasca Vacuum Residue Using Ni-Mo-Supported Drill Cuttings

“…The addition of a catalyst to HDC can reduce the operational severity while leading to more favorable products [7]. A HDC catalyst must have bi-functionality, consisting of dehydrogenation/ hydrogenation metals, for example, Co-Mo [8] or Ni-Mo [9], as well as a strong acidic support such as silica-alumina [10,11] that can crack the hydrocarbon molecules [12]. Good distribution and abundance of acidic and metallic sites on a HDC catalyst largely dictates its performance, as larger distances between sites impede the step-by-step reactions during HDC [13].…”

Hydrocracking of Athabasca VR Using NiO-WO3 Zeolite-Based Catalysts

“…A typical reaction scheme for HDC can be described as follows: initial dehydrogenation of the molecule on a metallic site, transport of the dehydrogenated molecule to an acidic site, cracking on the acidic site, transport to a metallic site, and finally hydrogenation of the cracked shorter chain molecules . Numerous studies have reported high HDC activity of Ni-W hydrogenation elements on a zeolite support. − There has been a growing interest in fabricating catalyst in the fiber form as opposed to particles, since fibers are less susceptible to agglomeration/aggregation. As such, fibers furnish more accessible active sites compared with particles .…”

“…5 While HDC is a relatively high temperature and pressure process, its operating conditions can be made less severe in the presence of a catalyst. 6 HDC catalyst is a bifunctional catalyst which comprises hydrogenation/dehydrogenation elements such as Ni-W, 7 Ni-Mo, 8 or Co-Mo 9 and an acidic support such as zeolite to crack the feed molecules. 10 The distance between the metallic and acidic sites on a catalyst largely impacts HDC performance, since the HDC reactions proceed in steps from site to site.…”