Dynamic and steady state analysis of low temperature ethane oxidative dehydrogenation over chromia and chromia-vanadia catalysts

Karamullaoglu, Gulsun
Doğu, Timur
Oxidative dehydrogenation of ethane to ethylene was investigated over Chromia and Cr-V mixed oxide catalysts synthesized following a complexation procedure. With an O-2/C2H6 feed ratio of 0.17, Chromia exhibited a total conversion value of about 0.20 at 447 degrees C (at a space time of 0.24 s.g/mL) with an ethylene selectivity of 0.82. Chromia catalyst was more active than Cr-V mixed oxide at temperatures as low as 200 degrees C. Pulse-response experiments carried out with ethane pulses injected into O-2-He indicated the presence of at least two different sites for the formation of CO2 and H2O over Chromia catalyst. In the dynamic experiments carried out with the Cr-V mixed oxide catalyst and by injecting O-2 pulses into a gas stream containing a mixture of C2H6 and He, formation of CO rather than C2H4 was favored. Results of the dynamic runs carried out without gas phase oxygen strengthened the conclusion of lattice oxygen participation in the selective oxidation of ethane reaction through a redox mechanism.


Oxidative dehydrogenation of ethane over a monolith coated by molybdenum-vanadium-niobium mixed-oxide catalyst
Karamullaoglu, G; Doğu, Timur (2003-10-01)
Oxidative dehydrogenation of ethane to ethylene was investigated using Mo0.71V0.21N0.08 mixed-oxide catalyst. in powder form and coated over a monolith. At 570degreesC and with a feed stream containing an O-2/C2H6 mole ratio of one. ethylene selectivity value reaching to 96% was obtained Lit a conversion level of about 5% with the monolith-supported catalyst. DRIFTS studies indicated the presence of adsorbed ethoxide species. The proposed reaction scheme for the production of ethylene includes the eliminati...
Breakthrough analysis of H2S removal on Cu-V-Mo, Cu-V, and Cu-Mo mixed oxides
Yasyerli, S; Dogu, G; Ar, I; Doğu, Timur (2003-05-01)
Kinetic studies carried out for the sorption of H2S in the presence and absence of hydrogen on Cu-V-Mo, Cu-V, and Cu-Mo mixed oxides gave detailed information about the reaction sequences. Formation of SO2 even in the presence of hydrogen at the initial stages of the sorption process showed the partial reduction of the metal oxides prior to the sulfidation step. A sorption experiment carried out with Cu-Mo mixed oxide gave incomplete sulfidation of molybdenum, whereas with Cu-V mixed oxide complete sulfidat...
Ethylene and acetaldehyde production by selective oxidation of ethanol using mesoporous V-MCM-41 catalysts
Gucbilmez, Yesim; Doğu, Timur; Balci, Suna (2006-05-10)
Vanadium-incorporated MCM-41 type catalytic materials, which were synthesized by a direct hydrothermal synthesis procedure, showed very high activity and high selectivity in the production of ethylene from ethanol in an oxidative process. Ethylene selectivity showed a significant increase with an increase in temperature over 300 degrees C, while relatively high acetaldehyde selectivities were observed at lower temperatures. An ethylene yield value of 0.66 obtained at 400 degrees C with an O-2/ethanol feed r...
Dynamic and steady-state analysis of oxidative dehydrogenation of ethane
Karamullaoğlu, Gülsün; Doğu, Timur; Department of Chemical Engineering (2005)
In this research, oxidative dehydrogenation of ethane to ethylene was studied over Cr-O and Cr-V-O mixed oxide catalysts through steady-state and dynamic experiments. The catalysts were prepared by the complexation method. By XRD, presence of Cr2O3 phase in Cr-O; and the small Cr2O3 and V2O4 phases of Cr-V-O were revealed. In H2-TPR, both catalysts showed reduction behaviour. From XPS the likely presence of Cr+6 on fresh Cr-O was found. On Cr-V-O, the possible reduction of V+5 and Cr+6 forms of the fresh sa...
Direct synthesis of Mg-Ni compounds from their oxides
Tan, Serdar; Aydınol, Mehmet Kadri; Öztürk, Tayfur; Karakaya, İshak (2010-08-13)
A study was carried out on the synthesis of Mg-Ni compounds as well as on the extraction of pure Ni and Mg from their oxides using the method of electro-deoxidation. The oxides sintered at 1200 degrees C were in the form of discrete phases NiO and MgO, suitably proportioned to yield Ni, MgNi2, Mg2Ni and Mg. The oxides were electrolyzed at 3.2 V in a eutectic mixture of CaCl2-NaCl solution maintained at a constant temperature (900-600 degrees C), using a graphite anode. The study has shown that NiO rich mixt...
Citation Formats
G. Karamullaoglu and T. Doğu, “Dynamic and steady state analysis of low temperature ethane oxidative dehydrogenation over chromia and chromia-vanadia catalysts,” INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING, pp. 0–0, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/53346.