Dry reforming of methane

Dry reforming of methane is gaining great interest owing to the fact that this process efficiently converts two greenhouse gases (CH4 and CO2) into synthesis gas (CO -I- H2), which can be further processed into liquid fuels and chemicals by Fischer-Tropsch and similar processes. 

The use of oxide-type perovskites as dry reforming catalysts will be dealt with extensively in Volume II of this book. In this chapter, we report one example of such catalyst in order to highlight the potentiahty of the nanocasting preparation method as a way to control bulk and smface properties of perovskite-derived catalysts. 

Ni-based catalysts have shown a great potential to replace noble metal catalysts in this reaction [73]. However, Ni-based catalysts also catalyze the 

Initial monitoring of the catalytic activity was performed using as-synthesized perovskites without any reduction step. In the case of conventional LaNiOs, very low values of conversions were observed for both CH4 and CO2 until 800 °C. For nanocast LaNiOs, comparatively higher conversions (approximately 40%) were 

LaNi03 (LN-CR)(GHSV = 2.1 xlO h ) (a). Variation of experimental product ratios under the same conditions is given in part (b) [27]. 

Levenspiel O. Chemical reaction engineering. 3rd ed. New York John Wiley Sons 1998. 

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The dry-reforming of methane is a technology that may pressurize the gas-to-liquid (GTL) approach by converting methane and C02 into liquid fuels at the liquefied natural gas (LNG) extraction well. 

Onstot, W.J., Minet, R.G. and Tsotsis, T.T. (2001) Design aspects of membrane reactors for dry reforming of methane for the production of hydrogen. Industrial e[ Engineering Chemistry Research, 40, 242-251. 

The so-called dry reforming of methane occurs at 600-800°C according to the reaction... 

Abashar, M. (2004). Coupling of steam and dry reforming of methane in catalytic fluidized bed membrane reactors, hit. ]. Hydrogen Energy 29, 799-808. 

Brungs, A.J., York, A.P.E., Claridge, J.B., Marquez-Alvarez, C., and Green, M.L.H. Dry reforming of methane to synthesis gas over supported molybdenum carbide catalysts. Catalysis Letters, 2000, 70 (3), 117. 

Laosiripojana, N. and Assabumrungrat, S. Catalytic dry reforming of methane over high surface area ceria. Applied Catalysis. B, Environmental, 2005, 60 (1-2), 107. 

Figure 4. Catalytic activity and stability for steam and dry reforming of methane.

Table 2 shows the initial results for the catalytic dry reforming of methane using bulk carbides of niobium, tantalum, molybdenum and tungsten, prepared by CH4 TPR. The conversions and yields obtained over P-M02C and a-WC are very similar to those predicted by thermodynamic considerations, and thus these materials are efficient catalysts for methane dry reforming. At atmospheric pressure, deactivation was observed over both catalysts after about 8 hours on stream. Examination of the post-catalytic samples by powder XRD (Figure 2) revealed that as the reaction proceeded the active P-M02C was oxidised and converted to... 

Results for the dry reforming of methane over group V and VI transition metal carbides. (GHSV = 2.87 X 10 h , CH4yCp2 = 1)... 

Dry Reforming of Methane Using Ternary Metal Carbides as Catalysts... 

As one possible method of processing large amounts of CO2, the dry reforming of methane process has been proposed (CO2 + CH4 —> 2CO + 2H2). Many investigations are continuously appearing in the literature for this... 

Tsyganok. A.I., Tsunoda, T., Hamakawa. S., Suzuki, K., Takchira, K. and Hayakawa, T. (2003). Dry reforming of methane over catalysts derived from niekel-containing Mg-AI layered double hydroxides. J. G/to/., 213, 191-203. 

S. Haag, M. Burgard and B. Ernst, Beneficial effects of the Use of a Nickel Membrane Reactor for the Dry Reforming of Methane Comparison with Thermodynamic Predictions, J. Calal.,252, 190-204 (2007). 

The experiments were performed in the Tapered Element Oscillating Microbalance (TEOM) reactor (7,8), in which carbon formation and deactivation could be measured simultaneously by coupling with on-line GC analysis. The dry reforming of methane was studied on an industrial Ni (11 wt%)/(Ca0)a-Al203 catalyst at temperatures of 500 °C and 650 °C, total pressures of 0.1 MPa and 0.5 MPa and a CO2/CH4 ratio of 1. The BET surface area of the catalyst was 5.5 m /g, and the Ni surface area 0.33 m /g. The detailed experimental procedures were similar to that reported previously (7). 

A direct comparison of the dry reforming of methane and LPG is apparently not available in the open literature. Such a comparison would be worthwhile, as would be greater emphasis on the LPG reaction rather than the methane reaction. 

Partial oxidation of methane is another way to produce water gas (Equation 1.3). This process is mainly used when we need lesser H2/CO ratio and if there are difficulties in external heat supply, internal heat generation is needed as in the case of fuel processors for fuel cell applications. Partial oxidation of methane produces H2/CO in a ratio of 2. If we need H2/CO in a ratio of 1, dry reforming of methane can be done (Equation 1.4). 

Bosko ML, Munera JF, Lombardo EA, Comaglia LM. Dry reforming of methane in membrane reactors using Pd and Pd-Ag composite membranes on a NaA zeolite modified porous stainless steel support. 7 Afemhr Sc/ 2010 364(1-2) 17-26. 

Corthals S, Van Nederkassel J, Geboers J, De Winne H, Van Noyen J, Moens B, Sels B, Jacobs P (2008) Influence of composition of MgAl204 supported NiCe02Zr02 catalysts on coke formation and catalyst stability for dry reforming of methane. Catal Today 138 (l-2) 28-32... 

Cobalt-based catalysts also attracted researehers attention as an aetive metal for dry reforming of methane. Cobalt-supported catalysts (Co/Zr02) modified with different metal additives were recently studied by Ozkara-Aydinoglu et The addition of manganese to Co/Zr02 improved the metal dispersion properties on the surface and had a stabilising effect on the catal3dic activity (80% of its activity was maintained after 6 h. Table 11.2, entry 9) with the suppression of coke formation nevertheless, this effect was not so pronounced as with other promoters. 

L. Paturzo, F. Gallucci, A. Basile, G. Vitulli and P. Pertid, An Ru-based catalytic membrane reactor for dry reforming of methane-its catalytic performance compared with tubular packed bed reactors, Catal. Today, 2003, 82, 57-65. 

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