Deutschmann, O.

Herrera Delgado, K.

Maier, L.

English

KITopen

KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz AssociationModeling oxidation and reforming of hydrogen, carbon monoxide, and methane over nickel catalystsKarla Herrera Delgado1, Lubow Maier2, Olaf Deutschmann1, 31 Institute of Chemical Technology and Polymer Chemistry2 Institute for Nuclear and Energy Technologies3 Institute for Catalysis Research and Technology IntroductionSimulation ResultsReferences:[1] V. F. Fischer, H.Tropsch, Brennstoff-Chemie, 3, 39 (1928)[2] S.Wang, G. Q. M. Lu, Appl.Catal. B: Environ, 16, 269 (1998)[3] O. Deutschmann, S. Tischer, et al, DETCHEMTM Software package, 2.3 ed., Karlsruhe (2010)Contact: K. Herrera Delgado, O. Deutschmann, Institute for Chemical Technology and Polymer Chemistry, Engesserstraße 20, 76131 Karlsruhe, Germany. karla.herrera@kit.edu,  deutschmann@kit.edu Presented at 45. Jahrestreffen Deutscher Katalytiker, Weimar/Germany, März  14.-16., 2012Figure 6. CH4 conversion in Dry Reforming of CH4/CO2 in a fixed-bed reactor over NiO/ɣ-Al2O3 [7]Figure 5.CH4 conversion in Steam reforming in a   (packed-bed) [6][4] L. Maier, B. Schädel, K. Herrera Delgado, S. Tischer, O. Deutschmann, Top Catal,54, 845 (2011)[5]C. Weeler, A.Jhalani, J. Catalysis, 223, 191 (2004)[6] J.-H. Ryu, K.Y. Lee, J. Power Sources 171, 499 (2007) ww.detchem.com[7] X. Chen, K. Honda, Z. Zhang, Appl. Catal. A: General, 288, 86 (2005)http://www.detchem.com http://www.itcp.kit.edu/deutschmannDuring the last years, there has been an increased interest in catalytic reforming of light hydrocarbons such as steam reforming (SR) and dry reforming (DR). The increasing concern of global warming and oil depletion offers the opportunity to convert greenhouse gases into synthesis gas (H2/CO), which is used in the manufacturing of valuable basic chemicals and synthetic fuels, as first shown by Fischer and Tropsch [1]. Industrial practice relies on Ni catalysts due to fast turnover rates, good availability and low costs, although it is more sensitive to carbon formation than noble metals [2]. The objective of this work is the development of a surface reaction mechanism applicable for catalytic conversion of hydrogen, carbon monoxide, and light hydrocarbons under oxidative, reforming, and pyrolysis conditions at a wide range of temperature, pressure, and residence timeModeling ApproachSurface science(TPD, XPS, AES, BET, IR ) Theory(DFT, MC, Collision)Lab experiments(conversion, selectivity, coverage)Reactor  Models(including models for gas phase kinetics and heat & mass transportSensitivity analysisEvaluation of crucial parametersInitial MechanismComparison of measured experiments and SimulationReliable mechanismMechanistic Model(mean field approximation)The  molecules are randomly distributed on the catalytic surfaceSurface is viewed as being uniform ΓcΘ iiiσ=Surface coverageΓstΘ iii σ&=∂∂Surface reaction rate∏∑+=sjkskNNjjKkiki cksg 'fνν&iieffii cMRTssπ2=&Adsorption rateRate expression∏=⎥⎦⎤⎢⎣⎡⎥⎦⎤⎢⎣⎡−=s1expexpNiiiµiaβkf RTΘεΘRTETAk kkikkkNumerical Simulation - DETCHEM SoftwarePACKEDBED1D Bed ReactorDETCHEM- LibraryReaction MechanismsThermodynamic and Transport DataMol DataSpeciesSENSITIVITY ANALYSIS MONOLITHTransient temperature profileof the solid structureBATCH + CSTRBatch and stirred tank CHANNEL or PLUG 1D or 2D-flow field simulations for a representative number of channels using a boundary layer or plug flow equations [3]Figure 2.H2 oxidation in a stagnation flow reactor over nickel cat. Inlet mol fractions: xH2= 4.78%, xO2= 2.89% in Ar, total flow = 15 L/min, Tinlet= 350°C, p= 0.5barFigure 3.CO oxidation in a packed-bed over nickel cat. Inlet composition of CO/O2= 1: 2 in Ar, total flow = 2 SL/min, Tinlet= 100°C, p= 1barFigure 4. CO conversion in Water-gas-shift reaction on Ni supported on alumina foam monolith [5]Figure 7. CO2 conversion in Dry Reforming of CH4/CO2 in a fixed-bed reactor over NiO/ɣ-Al2O3 [7]Figure 1.Sensitivity coefficients for CH4 mole fraction as function of temperature for CH4 steam reforming, S/C = 1.9 (75% Ar) [4]

Modeling oxidation and reforming of hydrogen, carbon monoxide, and methane over nickel catalysts

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Modeling oxidation and reforming of hydrogen, carbon monoxide, and methane over nickel catalysts

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