Using COMSOL for Chemical Reaction Engineering

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Using COMSOL for Chemical Reaction Engineering

• Your name
• COMSOL

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Overview

• COMSOL in two minutes
• The COMSOL product line
• Modeling in reaction engineering
• Reaction Engineering Lab
• COMSOL Multiphysics
• Example studies
• Heterogeneous catalysis
• Homogeneous catalysis
• Concluding remarks

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The company

• Released COMSOL Multiphysics in 98
• 150 employees
• 15 offices
• Network of distributors
• Growth of 30 last year

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The COMSOL product line
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Reaction Engineering

• Understanding the influence of chemical reactions
  in a process
• and using that knowledge to achieve goals
  in development and design
• Covers a broad range of applications on widely
  different scales

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Modeling in Reaction Engineering

• Modeling is a natural part of developing and
  optimizing chemical processes
• Enters at all levels
• Modeling the chemical reactions
• Calibrating the reaction model with experimental
  data
• Optimizing the chemical process in ideal reactors
• Exploring design in detailed reactor geometries

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Reactor Models

• Space and time-dependent tank reactor

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Reactor Models

• Ideal tank reactors are perfectly mixed

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Reactor Models

• Ideal tank reactors are perfectly mixed

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Reactor Models

• Space and time-dependent flow reactor

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Reactor Models

• Ideal tubular reactors are at steady-state

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Reactor Models

• Ideal tubular reactors are at steady-state

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Ideal or space-dependent models?

• Ideal reactors
• Well established concept
• Often adequate
• Computationally cheap
• Space-dependent reactors
• Detailed reactor information, e.g.
• Temperature distribution
• The effect of recirculation zones
• Detailed mass transport in concentrated mixtures
  etc
• Computationally demanding

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Reaction Engineering Lab

• Screen and evaluate reaction sets
• Calibrate the chemistry with experimental data
• Optimizing the chemical process in ideal reactors
• Transfer the kinetic model and physical
  properties of the reacting mixture from ideal
  reactors to space-dependent systems

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Chemical Reactions

• Screen reaction sets

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Chemical Reactions

• Calibrate the chemical model with experimental
  data

rate constants
k1 4.8 103 s-1 k2 4.9 106 s-1 k3 5.1 106
s-1
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Ideal Reactor Models

• Ideal tank reactors
• Batch reactor
• Semibatch reactor
• CSTR
• Ideal tubular reactors
• Plug-flow reactor

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Ideal Reactor Models

• Perform reactor analysis and design

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Space-dependent Models

• Transfer the kinetic model and physical
  properties of the reacting mixture from ideal
  reactors to space-dependent systems
• Move into detailed reactor analysis and design

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COMSOL Multiphysics

• Set up and solve time and space-dependent models
• Build your model by combining application modes
• Fluid flow
• Mass transport
• Energy transport
• Structural mechanics
• Electromagnetics
• Explore and optimize chemical processes in
  detailed reactor geometries

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Chemical Engineering Module

• Fluid flow application modes
• Laminar flow
• Turbulent flow
• Flow in porous media
• Non-Newtonian flow
• Compressible flow
• Two-phase flow

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Chemical Engineering Module

• Mass transport application modes
• Diffusion
• Convection and Diffusion
• Multi-component transport
• Ionic migration
• Energy transport application modes
• Conduction
• Convection and conduction
• Radiation

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NOx reduction in a catalytic converter

• Selective reduction of NO by NH3
• Honeycomb monolith with V2O5/TiO2 catalyst
• Plug-flow model
• Space-dependent model

Image courtesy of ArvinMeritor
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NOx reduction in a catalytic converter

• Competing reactions
• NO reduction by NH3
• NH3 oxidation
• Eley-Rideal kinetics
• Plug-flow model of a channel

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Reaction Engineering Lab
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Space-dependent model

• A cylindrical monolith channel
• Free flow in the center coupled to porous media
  flow in the catalytic wash-coat
• Reactions occur in the porous wash-coat

catalytic wash-coat
0.36 m
channel inlet
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COMSOL Multiphysics
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Homogeneous catalysis in a bubble column

• Ibuprofen synthesis
• Bubble column reactor with organometallic Pd
  catalyst in the liquid phase
• Ideal batch reactor model
• Space-dependent two-phase model

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Ibuprofen synthesis

• Homogeneous catalysis
• PdCl2(PPh3)
• Carbonylation reaction
• CO gas dissolves in the reacting phase

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Reaction Engineering Lab
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Space-dependent model

• Bubble column
• Two-phase flow
• Gas bubbles drive the flow
• 1 mm bubbles
• Volume fraction of gas 0,005, 0,001, 0,05
• Reactions occur in the liquid phase

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COMSOL Multiphysics
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Liquid flow as function of volume fraction of gas

• Vf 0.005
• Vf 0.001
• Vf 0.05

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Dissolution of CO gas in liquid

• Vf 0.005

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Dissolution of CO gas in liquid

• Vf 0.01

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Dissolution of CO gas in liquid

• Vf 0.05

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Concluding remarks

• Reaction Engineering Lab
• Explore chemical models
• Calibrate with respect to experiments
• Ideal reactor modeling
• COMSOL Multiphysics
• Space and time-dependent reactors
• Flow, mass and energy transport
• Arbitrary physics couplings