Hydrogen production from methane reforming: Thermodynamic assessment and autothermal reactor design

Abstract In this study, a comparative thermodynamic analysis of methane reforming reactions is conducted using an in-house code. Equilibrium compositions are calculated by two distinct methods: (1) evaluation of equilibrium constants and (2) Lagrange multipliers. Both methods result in systems of non-linear algebraic equations, solved numerically using the Scilab ( www.scilab.org ) function “fsolve”. Effects of temperature, pressure, steam to carbon ratio (S/C) (steam reforming), CH4/CO2 ratio (dry reforming), oxygen to carbon ratio (O/C) (oxidative reforming) and steam to oxygen to carbon ratio (S/O/C) (autothermal reforming) on the reaction products are evaluated. Comparisons between experimental and simulated data, published in the literature, are used to validate the simulated results. We also present and validate a small-scale reactor model for the autothermal reforming of methane (ATR). Using this model, the reactor design is performed and key operational parameters are investigated in order to increase both H2 yield and H2/CO selectivity. The reactor model considers a mass balance equation for each component, and the set of ordinary differential equations is integrated using the Scilab function “ode”. This ATR reactor model is able to describe the influence of temperature on methane conversion profiles, aiming to maximize hydrogen production. The experimental results and the model presented good agreement for methane conversion in all studied temperature range. Through simulated data of methane conversions, hydrogen yields and H2/CO selectivity, it is observed that the best reaction temperature to maximize the yield of hydrogen for the ATR reaction is situated between 723 and 773 K. Inside these bounds, 50% of methane is converted into products. Also, the experimental data indicates that the Ni catalyst activity is not compromised.

[1]  K. Kunimori,et al.  Catalytic performance and characterization of Pt-Ni bimetallic catalysts for oxidative steam reforming of methane , 2008 .

[2]  D. Borio,et al.  Kinetic evaluation of carbon formation in a membrane reactor for methane reforming , 2007 .

[3]  Kenji Maruyama,et al.  Temperature profiles of alumina-supported noble metal catalysts in autothermal reforming of methane , 2004 .

[4]  Paloma Ferreira-Aparicio,et al.  Development of biogas reforming Ni-La-Al catalysts for fuel cells , 2007 .

[5]  H. Arandiyan,et al.  Effects of Lanthanum Substitution by Strontium and Calcium in La-Ni-Al Perovskite Oxides in Dry Reforming of Methane , 2008 .

[6]  Keith D. King,et al.  Reforming of CH4 by partial oxidation: thermodynamic and kinetic analyses , 2001 .

[7]  Ahmed Aboudheir,et al.  Kinetics, experimental and reactor modeling studies of the carbon dioxide reforming of methane (CDRM) over a new Ni /CeO2-ZrO2 catalyst in a packed bed tubular reactor , 2007 .

[8]  J. van der Schaaf,et al.  Modeling and analysis of autothermal reforming of methane to hydrogen in a fixed bed reformer , 2008 .

[9]  L. Mattos,et al.  Partial oxidation of methane on Pt/Ce–ZrO2 catalysts , 2002 .

[10]  S. Kolaczkowski,et al.  Evaluation of thermodynamically favourable operating conditions for production of hydrogen in three different reforming technologies , 2002 .

[11]  S. Assabumrungrat,et al.  Synthesis gas production from dry reforming of methane over CeO2 doped Ni/Al2O3: Influence of the doping ceria on the resistance toward carbon formation , 2005 .

[12]  Nicolas Abatzoglou,et al.  Steam reforming of methane over unsupported nickel catalysts , 2006 .

[13]  Yaquan Wang,et al.  Partial oxidation of methane to syngas catalyzed by a nickel nanowire catalyst , 2009 .

[14]  G. Froment,et al.  Methane steam reforming, methanation and water‐gas shift: I. Intrinsic kinetics , 1989 .

[15]  Jens R. Rostrup-Nielsen,et al.  Syngas in perspective , 2002 .

[16]  Fortunato Migliardini,et al.  Hydrogen production by catalytic partial oxidation of methane and propane on Ni and Pt catalysts , 2007 .

[17]  Pio Forzatti,et al.  Catalytic partial oxidation of methane over a 4% Rh/α-Al2O3 catalyst Part II: Role of CO2 reforming , 2008 .

[18]  José Mansur Assaf,et al.  Autothermal reforming of methane over Ni/γ-Al2O3 catalysts: the enhancement effect of small quantities of noble metals , 2004 .

[19]  Dennis Witmer,et al.  Thermodynamic analysis of hydrogen production by steam reforming , 2003 .

[20]  H. Al-Qahtani.  Effect of ageing on a steam reforming catalyst , 1997 .

[21]  J. C. Schouten,et al.  Design of adiabatic fixed-bed reactors for the partial oxidation of methane to synthesis gas. Application to production of methanol and hydrogen-for-fuel-cells , 2001 .

[22]  Y. Schuurman,et al.  Transient studies of carbon dioxide reforming of methane over Pt/ZrO2 and Pt/Al2O3 , 2006 .

[23]  S. Chan,et al.  Hydrogen production for fuel cells by autothermal reforming of methane over sulfide nickel catalyst on a gamma alumina support , 2006 .

[24]  Y. Duan,et al.  Correlations for second and third virial coefficients of pure fluids , 2004 .

[25]  C. Mondelli,et al.  Supported Rh catalysts for methane partial oxidation prepared by OM-CVD of Rh(acac)(CO)2 , 2008 .

[26]  Shuyan Wang,et al.  Simulation of effect of catalyst particle cluster on dry methane reforming in circulating fluidized beds , 2007 .

[27]  Olaf Deutschmann,et al.  Steam reforming of methane, ethane, propane, butane, and natural gas over a rhodium-based catalyst , 2009 .

[28]  Sven Järås,et al.  Partial oxidation of methane over Pt–Ru bimetallic catalyst for syngas production , 2008 .

[29]  David L. Trimm,et al.  The combustion of methane on platinum—alumina fibre catalysts—I: Kinetics and mechanism , 1980 .

[30]  Ryuji Kikuchi,et al.  Catalytic autothermal reforming of methane and propane over supported metal catalysts , 2003 .