Synthesis and characterization of a La-Ni/α-Al_2O_3 catalyst and its use in pyrolysis of glycerol to syngas

摘要

The current paper reports on the kinetics of syngas production from glycerol catalytic pyrolysis over Nil alpha-Al(2)O(3)a catalyst promoted by lanthanum. The 3 wt%La-20 wt%Ni/77 wa%alpha-Al2O3 catalyst was synthesized and its physiochemical properties were characterized. The BET specific surface area was 2.20 m(2).g(-1), which was 0.11 m(2).g(-1) larger than the unpromoted Ni/alpha-Al2O3 catalyst. Significantly, the BET results were supported by the FESEM image which showed that the promoted catalyst has smaller particle size compared to the unpromoted catalyst. The NH3- and CO2-TPD analyses indicates that the catalyst has net acidity with acid:base ratio of 1.12. Catalytic pyrolysis was performed in a 10 mm-ID stainless steel fixed bed reactor with reaction temperatures set at 973, 1023 and 1073 K, employing a weight-hourly-space velocity (WHSV) of 4.5 x 10(4) ml g(-1) h(-1). From reaction studies, the highest glycerol conversion (X-G) value was 36.96% at 1073 K. The resulting syngas has H-2:CO ratios always lower than 2.0. Subsequently, mechanistic studies indicate that the catalytic glycerol pyrolysis occurred on single catalytic site via associative adsorption, with molecular surface reaction as the rate-determining step. (C) 2018 Elsevier Ltd. All rights reserved.