Hydrodynamic analogy approache Idea: Development of analogies between real complex fna mics and geometrically simpler flow patterns based on experimental observations Characteristics: Allows an extension of the application of partial • differential equations to morecomplex objects and processes Model parameters are directly • derived from the geometry of internals Results obtained: Pertracton (liquid membrane ex- • traction) Microdistillation • Distillation in structured packed • columns Reactive stripping in packed • columns and monoliths Fluid-dynamics approach Idea: Column sub-division onto segments (stages) and their kinetics-based description Characteristics: Suitable in design and optimisation tasks for many staged • operations, including reactive and hybrid separations Weak point is that accuracy and predicti- • vity strongly depend on the quality of mo- del parameters Results obtained: Distillation and reactive distillation • (Reactive) absorption and desorption • Reactive Stripping • Non-Reactive and reactive • dividing wall columns Different Systems, units, internals • Steady-state and dynamic simulations • Optimisation studies • Fluid-dynamics approach Idea: Process description by partial differential equations of fluid dynamics Characteristics: Provides full information about the process (velocity,temperature • and concentration field) in a purely theoretical way • Difficult to apply for complex multiphase flow patterns • Results obtained: Fim flows (cocurrent and countercurrent, laminar • and turbulent, binary and multicomponent, one-, two- and three-phase, non-reactive) Liquid droplet and layer phenomena • Monoliths • Microseparations • Principle Complementary Modelling of Fluid Separation Processes Outline and Main Results Lehrstuhl für Fluidverfahrenstechnik Universität Paderborn www.uni-paderborn.de/fvt Extension Virtual experiments Idea: Replacement of empirical parameter estimation by model- based simulations for different basic types of column internals Characteristics: Extracts information from the investigation of small • periodic representative elements of real internals (usually via CFD) Provides a link between FDA and RBA/HA • Potentially, a way to virtual prototyping internals, however • still in the early stage Results obtained: Pressure drop in fixed beds • and structured packings Residence time distribution • in catalytic packings Gas-liquid mass transfer coefficients in • catalytic packings Liquid-solid mass transfer • coefficients in fixed catalyst beds Despite that different fluid separations have much in common, a unified approach to their modelling is missing. This is mainly due to the diversity of operating, scale and boundary conditions as well as due to the significant modelling difficulties. A unified modelling approach is particularly difficult to formulate when a direct account of the process rates (transport and reaction kinetics) is essential, which is common in design and optimisation tasks. Therefore, we suggest an alternative way and present a novel modelling methodology which comprises different specific kinetics-based approaches and combine them in a complementary way. Such complementary modelling is a promising means to support the development of sustainable chemical engineering processes. Virtual experiments Fluid dynamics approach Hydrodyna- mic analogies Rate-based approach Idea: Reaction kinetics measurements for CO 2 absorption into aqueous blends of alkanolamines prepared from renewable resources Characteristics: Data are obtained in a stirred cell reactor with a plane, horizontal • gas-liquid interface Easy-to-use experimental device operated batch-wise • The method is based on a simple fall-in-pressure technique, • without measurements of concentrations Results obtained: Absorption of CO2 into aqueous solutions containing N,N- • diethylethanolamine (DEEA), N-ethylethanolamine (EEA) and their blends Reaction acceleration by piperazine (PIP) • Contact: [email protected] +49 (0) 5251 / 60-2408 www.uni-paderborn.de/fvt ethylbenzene / chlorobenzene (EB / CB) A. Shilkin & E. Y. Kenig 2005, Chem Eng J., 110,87-100 A. Shilkin, E. Y. Kenig, Z. Olujic, 2006, AIchE Journal, 52,3055-3066 methanol / acetonitrile / water (MEOH / ACN / WATER) Experimental Setup Absorption rates at 303K P.D. Vaidya & E.Y. Kenig, 2007, Chem. Eng. Sci., 62, 7344-7350 T.Atmakidis & E. Y. Kenig, 2007, Escape17, Bucharest, Romania T.Atmakidis & E. Y. Kenig, 2007, Escape17, Bucharest, Romania C. Grossmann, E. Y. Kenig, 2007, CIT plus, No. 5, 38-41 Y. Egorov, F. Menter, M. Klöker & E.Y. Kenig, 2005, Chem. Eng. Process., 44, 631-644 Fluid dynamics complexity within the process Modelling rigour
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Hydrodynamic analogy approacheIdea: Development of analogies between real complex fna micsandgeometricallysimplerflowpatternsbased on experimental observations
Characteristics: Allows an extension of the application of partial •
differential equations to morecomplex objects and processes
Model parameters are directly •derived from the geometry of internalsResults obtained:
Pertracton (liquid membrane ex-•traction)
Microdistillation•Distillation in structured packed •columnsReactive stripping in packed • columns and monoliths
Fluid-dynamics approachIdea: Column sub-division onto segments (stages) and their kinetics-based descriptionCharacteristics:
Suitable in design and optimisation tasks for many staged •operations, including reactive and hybrid separationsWeak point is that accuracy and predicti-•vity strongly depend on the quality of mo-del parameters
Results obtained:Distillation and reactive distillation•(Reactive) absorption and desorption•Reactive Stripping•Non-Reactive and reactive •dividing wall columnsDifferent Systems, units, internals•Steady-state and dynamic simulations•Optimisation studies•
Fluid-dynamics approachIdea: ProcessdescriptionbypartialdifferentialequationsoffluiddynamicsCharacteristics:
Provides full information about the process (velocity,temperature •andconcentrationfield)inapurelytheoreticalway•Difficulttoapplyforcomplexmultiphaseflowpatterns•
Results obtained:Fimflows(cocurrentandcountercurrent,laminar •and turbulent, binary and multicomponent, one-, two- and three-phase, non-reactive)Liquid droplet and layer phenomena•Monoliths•Microseparations•
Prin
cipl
e
Complementary Modelling of Fluid Separation Processes
Out
line
and
Mai
n R
esul
ts
Lehrstuhl für Fluidverfahrenstechnik Universität Paderborn www.uni-paderborn.de/fvt
Ext
ensi
on
Virtual experimentsIdea: Replacement of empirical
parameter estimation by model- based simulations for different basic
types of column internalsCharacteristics:
Extracts information from the investigation of small • periodic representative elements of real internals (usually
via CFD) Provides a link between FDA and RBA/HA•Potentially, a way to virtual prototyping internals, however •still in the early stage
Results obtained:Pressuredropinfixedbeds •
and structured packingsResidence time distribution •
in catalytic packingsGas-liquidmasstransfercoefficientsin •
catalytic packingsLiquid-solid mass transfer •
coefficientsinfixed catalyst beds
Despitethatdifferentfluidseparationshavemuchincommon,aunifiedapproachtotheirmodellingismissing.Thisismainlyduetothediversityofoperating,scaleandboundaryconditionsaswellasduetothesignificantmodellingdifficulties.Aunifiedmodellingapproachisparticularlydifficulttoformulatewhenadirectaccountof the process rates (transport and reaction kinetics) is essential, which is common in design and optimisation tasks.Therefore,wesuggestanalternativewayandpresentanovelmodellingmethodologywhichcomprisesdifferentspecifickinetics-basedapproachesandcombinetheminacomplementaryway.Suchcomplementarymodellingisapromisingmeanstosupportthedevelopmentofsustainablechemicalengineeringprocesses.
Virtual experiments
Fluid dynamics approach
Hydrodyna-mic analogies
Rate-based approach
Idea: Reaction kinetics measurements for CO2 absorption into aqueous blends of alkanolamines prepared from renewable resourcesCharacteristics:
Data are obtained in a stirred cell reactor with a plane, horizontal • gas-liquid interface Easy-to-use experimental device operated batch-wise• The method is based on a simple fall-in-pressure technique, •
without measurements of concentrationsResults obtained:
Absorption of CO2 into aqueous solutions containing N,N- • diethylethanolamine (DEEA), N-ethylethanolamine (EEA) and their blends
Reaction acceleration by piperazine (PIP)•
Contact:[email protected]+49 (0) 5251 / 60-2408www.uni-paderborn.de/fvt
ethylbenzene / chlorobenzene (EB / CB)
A.Shilkin&E.Y.Kenig2005,ChemEngJ.,110,87-100
A.Shilkin,E.Y.Kenig,Z.Olujic,2006,AIchEJournal,52,3055-3066
methanol / acetonitrile / water (MEOH / ACN / WATER)
Experimental Setup Absorptionratesat303K
P.D.Vaidya&E.Y.Kenig,2007,Chem.Eng.Sci.,62,7344-7350
T.Atmakidis&E.Y.Kenig,2007,Escape17,Bucharest,Romania
T.Atmakidis&E.Y.Kenig,2007,Escape17,Bucharest,Romania
C.Grossmann,E.Y.Kenig,2007,CITplus,No.5,38-41
Y.Egorov,F.Menter,M.Klöker&E.Y.Kenig,2005,Chem.Eng.Process.,44,631-644
Fluid dynamics complexitywithin the process
Mod
ellin
g rig
our
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