Partial oxidation of ethane to syngas over nickel-based catalysts modified by alkali metal oxide and rare earth metal oxide

The catalytic activity, thermal stability and carbon deposition of various modified NiO/gamma-Al2O3 and unmodified NiO/gamma-Al2O3 catalysts were investigated with a flow reactor, XRD, TG and UVRRS analysis. The activity and selectivity of the NiO/gamma-Al2O3 catalyst showed little difference from those of the modified nickel-based catalysts. However, modification with alkali metal oxide (Li, Na, K) and rare earth metal oxide (La, Ce, Y, Sm) can improve the thermal stability of the NiO/gamma-Al2O3 and enhance its ability to suppress carbon deposition during the partial oxidation of ethane (POE). The carbon deposition contains graphite-like species that were detected by UVRRS. The nickel-based catalysts modified by alkali metal oxide and rare earth metal oxide have excellent catalytic activities (C2H6 conversion of similar to 100%, CO selectivity of similar to 94%, 7x 10(4) l/(kg h), 1123 K), good thermal stability and carbon-deposition resistance.

The formation of Co2C species in activated carbon supported cobalt-based catalysts and its impact on Fischer-Tropsch reaction

The cobalt carbide (Co2C) species was formed in some activated carbon supported cobalt-based (Co/AC) catalysts during the activation of catalysts. It was found that the activity of Fischer-Tropsch reaction over Co-based catalysts decreased due to the formation of cobalt carbide species. Some promoters and pretreatment of activated carbon with steam could restrain the formation of cobalt carbide.

Autothermal reforming of n-octane on Ru-based catalysts

In an attempt to effectively integrate catalytic partial oxidation (CPO) and steam reforming (SR) reactions on the same catalyst, autothermal reforming (ATR) of n-octane was addressed based on thermodynamic analysis and carried out on a non-pyrophoric catalyst 0.3 wt.% Ru/K2O-CeO2/gamma-Al2O3. The ATR of n-octane was more efficient at the molar ratio Of O-2/C 0.35-0.45 and H2O/C 1.6-2.2 (independent parameters), respectively, and reforming temperature of 750-800 degrees C (dependent parameter). Among the sophisticated reaction network, the main reaction thread was deducted as: long-chain hydrocarbon -> CH4, short-chain hydrocarbon -> CO2, CO and H-2 formation by steam reforming, although the parallel CPO, decomposition and reverse water gas shift reaction took place on the same catalyst. Low temperature and high steam partial pressure had more positive effect on CH4 SR to produce CO2 other than CO. This was verified by the tendency of the outlet reformate to the equilibrium at different operation conditions. Furthermore, the loss of active components and the formation of stable but less active components in the catalyst in the harsh ATR atmosphere firstly make the CO inhibition capability suffer, then eventually aggravated the ATR performance, which was verified by the characterizations of X-ray fluorescence, BET specific surface areas and temperature programmed reduction. (c) 2005 Elsevier B.V. All rights reserved.