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Maldistribution Effects in an Industrial-Scale Trickle Bed Reactor

Jejurkar, Swarup Y., Khanna, Ashok, Verma, Nishith
Industrial & engineering chemistry process design and development 2020 v.59 no.16 pp. 7405-7415
catalysts, heat, interphase, momentum, porosity, temperature
Phasic maldistribution triggers hot spots within the catalyst bed in a trickle bed reactor. We investigate hot spot formation during hydrodesulphurization of diesel to understand the role of physical obstacles and catalyst fines as possible causes of hot spots. Transport processes at the industrial scale are modeled using a three-phase semi-empirical Eulerian–Eulerian framework incorporating interphase transport and Langmuir–Hinshelwood kinetics. The growth and dissipation of hot spots in radial and axial directions depend on the gradients in the radial direction within the phases. Blockage of the inlet significantly influences thermal conditions within the bed. Maldistribution of the momentum and scalar fields caused by the blockage establishes hot zones downstream of the blocked inlet. They extend radially and axially, with an increase in local temperature by as much as 10°. Distributed porosity develops a highly two-dimensional flow and hot spots relative to other locations in the bed because of differential heating.