Tutorial Modeling of monolith reactors

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The effectiveness factor Because the washcoat thickness is not explicitly modelled, the washcoat diffusion is incorporated using an effectiveness factor, defined as: η = Average reaction rate in washcoat Rate evaluated at surface conditions The effectiveness factor can be estimated from a submodel that usually involves solving a 1D diffusion-reaction problem. Washcoat geometry effects may be included. Hayes, et al Chemical Engineering Science, 62 2209-2215, 2007. Hayes, et al Chemical Engineering Science, 59 3169-3181, 2004. 50
Models for the converter • In reality the channels in the converter may not all have the same operating conditions. • The substrate constrains the velocity and concentrations to each channel, but heat transfer can occur among the channels. • A model <strong>of</strong> the entire converter may therefore be required. There are two general methods for modelling a converter: – Discrete models – Continuum models 51
Page 1 and 2: Introduction to Monolith Reactor Mo
Page 3 and 4: Why use computer modelling? • Exp
Page 5 and 6: Observations • The problem involv
Page 7 and 8: Model Scales Micro scale: At the at
Page 9 and 10: Mathematical formulation • The fu
Page 11 and 12: Basic models in common use • Sing
Page 13 and 14: The 3D SCM • The real monolith do
Page 15 and 16: The 2D approximate SCM • The 2D m
Page 17 and 18: The 2D SCM • All of the physical/
Page 19 and 20: Modelling the fluid domain Velocity
Page 21 and 22: Modelling the washcoat domain • T
Page 23 and 24: Diffusion in the washcoat • Diffu
Page 25 and 26: Modelling the substrate domain The
Page 27 and 28: Comparing 2D and 3D models • The
Page 29 and 30: Comparing 2D and 3D models • The
Page 31 and 32: Comparing 2D and 3D models Percenta
Page 33 and 34: Review of boundary layer flow Flow
Page 35 and 36: Boundary layers in a tube • At th
Page 37 and 38: Heat and mass transfer • Heat and
Page 39 and 40: 1D SCM mass balances The fluid phas
Page 41 and 42: 1D SCM energy balances The fluid ph
Page 43 and 44: Nusselt and Sherwood numbers • Fo
Page 45 and 46: Nusselt and Sherwood numbers • Ho
Page 47 and 48: Nusselt and Sherwood numbers • Ho
Page 49: Simplified 1D models • Dispersion
Page 53 and 54: Discrete converter models • A pas
Page 55 and 56: Momentum balance equation Velocity
Page 57 and 58: Energy balances The fluid phase ene
Page 59 and 60: Continuum model • In effect, the
Page 61 and 62: Model validation • All models mus
Page 63 and 64: Model validation - Example Heating
Page 65: Advertising supplement R.E. Hayes a

Tutorial Modeling of monolith reactors

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