Autothermal Partial Oxidation of Glycerol to Syngas over Pt-, LaMnO₃-, and Pt/LaMnO₃-Coated Monoliths

Abstract

Glycerol and glycerol/water solution were converted to syngas over Pt-, LaMnO 3 -, and Pt/LaMnO 3 -coated monoliths under autothermal partial oxidation. XRD and SEM were used to characterize the phase compositions and surface morphologies of freshly prepared and postreaction catalysts. A continuous fixed-bed design, without an upstream vaporizer or external heat supply, was operated at millisecond contact times. Among the catalysts used in this study, Pt was the least reactive, and its activity was found to be reduced by sintering. Pt also tended to produce nonequilibrium products such as ethylene and acetaldehyde in fuel-rich environments. In contrast, LaMnO 3 was found to favor glycerol combustion, producing fewer minor products and generating sufficient heat to sustain autothermal operations in fuel-and steam-rich regimes. Pt supported on LaMnO 3 showed a synergistic effect of Pt sintering suppression and a broad H 2 /CO distribution in the resulting syngas. This effect can be correlated to the interaction between Pt and LaMnO 3 .

Structured nanocomposite catalysts of biofuels transformation into syngas and hydrogen: Design and performance

“…At 800 C decreasing the oxygen content in the feed to 10% increases exit H 2 content by~3% and decreases CO 2 content by~5%, while CO concentration remains constant. Syngas selectivity (SH 2~6 0% and SCO~60%) is close to that obtained at millisecond contact times for cordieritesupported LaMnO 3 and LaNiO 3 [8,28], while in steam reforming of glycerol SCO 2 is higher than SCO [27].…”

“…Concentrations of such byproducts as CH 4 and C 2 H 4 are reasonably low, though apparently liquid phase by-products (acetone, acetaldehyde, acrolein, methanol, ethanol, hydroxyacetone, acetic acid, propionic acid, propylene glycol, ethylene glycol, acrolein etc.) [8,27,28] are formed in this reaction in the low-temperature range.…”

“…Though perovskite-coated cordierite monoliths were reported to operate in the autothermal mode at somewhat shorter (18e80 ms) contact times than the package of microchannel plates (200e300 ms), however, glycerol conversion on honeycomb catalysts was not complete varying in the range of 40e95% as dependent upon the feed composition and timeon-stream [8,28]. Hence, further optimisation of microchannel configuration as well as C/O and S/C ratio will certainly allow to provide complete conversion of glycerol along with a high syngas yield at shorter contact times than in present experiments.…”

Review of catalytic syngas production through steam or dry reforming and partial oxidation of studied liquid compounds

“…The higher interaction between the deposited Pt metal and the perovskite support almost completely inhibited sintering phenomena without altering the catalyst's POX activity. SEM pictures showed that Pt grain size distribution was not changed over 28‐h TOS, as shown in Figure . The data were not similar for Ni and Pd.…”

“…The main drawback of Rh/CeO 2 ‐based catalyst was the sintering phenomena observed over TOS. Liu and Lin observed that this drawback can be remedied with LaMnO 3 perovskite as a Pt‐based POX catalyst. The higher interaction between the deposited Pt metal and the perovskite support almost completely inhibited sintering phenomena without altering the catalyst's POX activity.…”