In this study hydrogen production
from the autothermal reforming
(ATR) of glycerol was investigated in a packed bed tubular reactor
using nickel-based catalysts with theoretical composition of 5% Ni/Ce0.5Zr0.33M0.16O2−δ, where M is the promoter element selected from Mg, Ca, Y, La, or
Gd. The structural, textural, and physicochemical characteristics
of the catalysts were investigated using various characterization
techniques. The catalytic activity was evaluated in a temperature
range from 450 to 700 °C; steam-to-glycerol (S/G) ratio of 6,
9, and 12; and oxygen-to-glycerol (O/G) ratio of 0.2, 0.5, and 0.8
at atmospheric pressure. Among all the catalyst formulations prepared
in the current study, 5Ni/CeZrGd exhibited the best catalytic performance
and stability compared to the other promoter elements. For 5Ni/CeZrGd
catalysts, it was found that, until 600 °C, conversion increased
rapidly with the increase in temperature to reach 82 mol % glycerol
conversion and more than 70 mol % H2 selectivity, which
can be optimal operation conditions for industrial applications. Furthermore,
the increase of O/G ratio showed similar trends. Although adding more
S/G in the feed did not show any noticeable increase in glycerol conversion,
it resulted in lower hydrogen concentration in the reformate product
due to the dilution effect of steam.