Barbato Maurizio - ICIMSI – DTI, SUPSI Manno (Switzerland)
D. Vella Luigi - Department of Materials Science and Chemical Engineering, Politecnico di Torino (Italy)
Specchia Stefania - Department of Materials Science and Chemical Engineering, Politecnico di Torino (Italy)
Specchia Vito - Department of Materials Science and Chemical Engineering, Politecnico di Torino (Italy) |
A two dimensional axial symmetric model has been developed for simulating an Experimental Short Contact Time (SCT) reactor suitable for Catalytic Partial Oxidation (CPO) of a Methane-Oxygen mixture.
The experimental apparatus to be modeled is a cylindrical steady flow reactor [1] with a series of fixed beds: a mixing zone with small quartz cylinders, a preheating zone with small SiC spheres, a catalytic bed formed by alumina spheres impregnated with Rodhium and finally a cooling region of small quartz cylinders. Oxygen and Methane are flown through the reactor and, after the mixing, the CPO, occurring
thanks to the Rhodium covered spheres, produces H2, CO and other secondary species.
The CFD model, developed with the sw ANSYS-Fluent, uses the porous media approach to simulate the fixed bed regions. The reactive laminar flow model accounts for both, homogeneous and heterogeneous chemical reactions. The homogeneous chemical kinetics mechanism is based on the GRI 3.0 suitable for CH4 oxidation [2] and includes 35 chemical species and 217 reactions. The heterogeneous mechanism for CH4 oxidation on Rhodium is the one of Deutschmann et al. [3]. Transport properties for pure gaseous species are based on the kinetic theory of gases.
The numerical performances of the model have been validated by checking the truncation error effects and by varying the numerical schemes. The sensitivity of results to the thermal properties model used for the porous zones has been tested by comparing constant and temperature dependent thermal properties for Quartz, SiC and Alumina.
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