Main content area

Applied kinetics for modeling of reactive hot gas filters

Rhyner, Urs, Edinger, Philip, Schildhauer, Tilman J., Biollaz, Serge M.A.
Applied energy 2014 v.113 pp. 766-780
activation energy, adsorption, benzene, biomass, catalysts, ethane, ethylene, filters, foams, gasification, methane, models, producer gas, steam, sulfur, temperature, toluene
First order kinetics were developed based on experimental results of a noble metal catalyst. Activation energies and pre-exponential factors were determined by parameter estimation for steam reforming of tars, sulfur tars and ethene. The formation of ethane and benzene was assumed to be at constant rate depending on the decomposition of ethene and toluene respectively. Further, for steam reforming of methane and water gas shift reaction, the kinetic parameters of Langmuir–Hinshelwood–Hougen–Watson (LHHW) type rate laws including equilibrium term and adsorption of sulfur could be determined.With the applied kinetics, catalytic tar conversion of producer gas from biomass gasification was simulated. Simulation results at operating temperatures of 850°C showed significantly higher conversions rates for sulfur free tars, ethene and methane than at 600°C or 750°C while the conversion of sulfur tars was less temperature dependent and high at all temperatures.The simulation results were used to evaluate different possibilities regarding the integration of catalytic material into hot gas filter units with vertical and horizontal filter design. The option of catalytic active filter elements, additional catalytic foam type packing at the inside of the filter element and a monolith at the exit of the filter vessel are feasible assuming the same catalyst material as applied in the reforming catalyst used in this study. These three options can be applied independently of the horizontal or vertical filter design. Placing a catalytic monolith or foam structure at the filter candle exit of a horizontal filter design was found to be unrealistic because the monolith or foam structure would be too long to reach sulfur tar concentrations below 1ppmV.