Lc. Castaneda-lopez et al., Comparison of the performance of upflow and downflow small-reactors in hydrodesulfurization reactions, ENERG FUEL, 15(5), 2001, pp. 1139-1144
An experimental study for comparing the behavior of a small-reactor in the
hydrodesulfurization of straight-run gas oil with two modes of operation, u
pflow and downflow, is presented. The reactor has 525 min length and 14.3 m
in internal diameter. Experiments were conducted at commercial HDS operatin
g conditions (5.3 MPa total pressure, 356.2 mL/mL hydrogen-to-oil ratio, re
action temperature of 613-653 K, and LHSV of 1.0-2.5 h(-1)). All tests were
carried out over a commercial NiMo/gamma -Al2O3 catalyst. The effect of di
fferent catalyst-to-diluent ratios on the sulfur removal was also studied.
The results of SRGO hydrodesulfurization showed that upflow with a 50/50 vo
l % catalyst-to-diluent ratio is the best system to avoid external gradient
s and other effects such as poor wetting of catalyst, axial dispersion, wal
l effects, and flow maldistribution. Apparent activation energies were dete
rmined for upflow and downflow modes of operation with and without diluent.