Recent Advancements in Biofuels and Bioenergy Utilization by Prakash Kumar Sarangi & Sonil Nanda & Pravakar Mohanty

Author:Prakash Kumar Sarangi & Sonil Nanda & Pravakar Mohanty
Language: eng
Format: epub
ISBN: 9789811313073
Publisher: Springer Singapore

8.3.6.3 Temperature-Programmed Oxidation Measurements

Although the type of deposited carbon (i.e. graphitic and amorphous carbons) on spent catalysts could be determined via Raman analysis, quantifying the amount of carbonaceous species by TPO measurements is essential for the justification of catalytic performance. Figure 8.16 shows the derivative weight profiles of spent promoted and unpromoted catalysts during TPO measurements. For all catalysts, the first oxidation peak, P1 located at low temperature region of 700–750 K, was due to the gasification of more reactive carbon, i.e. amorphous carbon, whilst the high-temperature peak (P2) observed at 750–850 K could belong to the elimination of less reactive graphitic carbon (Bartholomew 2001) in agreement with results from Raman analyses (see Fig. 8.15). Da Silva et al. (2011) also observed the heterogeneity of deposited carbon on spent EDR catalyst. Indeed, the amorphous or filamentous carbons were reportedly formed from the polymerization of intermediate ethylene generated from ethanol dehydration, whilst ethanol and methane decomposition could induce the formation of graphite or crystalline carbon (Zawadzki et al. 2014).

Fig. 8.16Weight percentage and derivative weight profiles of spent (a) 10%Co/Al2O3, (b) 3%Ce-10%Co/Al2O3 and (c) 3%La-10%Co/Al2O3 catalysts after EDR reaction at = = 20 kPa and T = 973 K

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