Effects of Different Structures of Porous Solids on Diffusion of Gases in the Transition Region

Modelling the Hydrothermal Ageing of a Fe‐Zeolite Catalyst for Automotive NH3‐SCR Applications

“…In more detail, the 1D + 1D model is characterized as follows: i) a 1D approach describes reaction, heat and mass transfer phenomena along the monolithic channels, based on the assumption of identical conditions within each channel of the catalyst and negligible axial dispersions and pressure drops; ii) the additional 1D submodel describes reaction and diffusion within the porous structure of the catalytic washcoat on the channel walls. The model accounts for both internal and external mass transfer limitations: external mass transfer resistances are evaluated by a well-established correlation for gas-solid mass transfer coefficients in honeycomb monoliths [17], while the evaluation of intra-phase diffusional limitations requires the estimation of effective diffusivities of the gaseous reactant in the porous catalyst according to a modified Wakao-Smith correlation [18].…”

Laboratory characterization of the structural properties controlling dynamical gas transport in Mars-analog soils

“…denotes access to a variety of assayed mixtures of helium and argon used in the calibration of the thermal conductivity detector. Geankoplis, 1968;Satterfield and Cadle, 1968). Fig.…”

Modelling Inhibition Effects of Short-Chain Hydrocarbons on a Small-Pore Cu-Zeolite NH3-SCR Catalyst

“…Enthalpy balances for the gas and for the solid phase are included to account also for thermal effects. In addition, external (gas-solid) mass transfer coefficients are estimated according to wellestablished correlations for laminar flow in square monolith channels, while intra-phase diffusional limitations are accounted for by solving equations for diffusion-reaction of the gaseous species in the porous catalytic washcoat, using species effective diffusivities [9,10].…”