DISTILLATION CALCULATIONS

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DISTILLATION CALCULATIONS OVER THE NET K.
Jakobsson1, K.I. Keskinen1,2, J. Aittamaa1 1
Helsinki University of Technology, Finland,
Address Kemistintie 1 M, POB 6100, FI-02015
HUT, Finland. Email Kaj.Jakobsson_at_hut.fi, fax
358-9-451 2694 2Neste Jacobs Oy, POB 310,
FI-06101 Porvoo, Finland
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Contents

• Motivation
• Flowbat program
• Distillation modules
• Real stage models (plates and packings)
• Efficiencies
• Flow on large plates
• Non-ideal reboilers
• Web
• Conclusions

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Motivation

• Free the user from
• a particular computer or time
• Centralise the support and maintenance work for
  the developer

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Flowbat

• Steady state
• Unit modular
• Flowsheeting program

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Includes

• Library of unit models
• Thermodynamics
• Physical properties
• Databank
• Optimisation

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Web-Flowbat

• Database restricted to 1000 components
• Calculation time restricted

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Separation Units

• Rigorous distillation
• Rigorous reactive distillation
• Interconnected External Reactor and Reactive
  Distillation
• Column, stripper or absorber
• Rate based distillation
• Liquid-Liquid separator, decanter
• Multicomponent gas phase membrane separator

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Two Models for Real Plates
Efficiency based
Rate-based
Equilibrium
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Efficiency
Multicomponent Murphree efficienies
Point efficiency
(Krishna et al., 1977)
Small plates
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Matrix of Overall NTUs
Two film theory relates overall NTUs to vapor
and liquid phase NTUs
(Taylor and Krishna,1993), Aittamaa (1981)
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Large Plates
Rate-based model Cell Model
Efficiency based model
Mixed pool model
Higler, A., Krishna, R., Taylor, R., (1999)
Pyhälahti Jakobsson (2004) Kenig et al. (2004)
Ilme (1997)
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Packed Columns
Efficiency based model
Rate-based model
Used as such
Calculation of a comparable efficiency to
Murphree vapor phase efficiency
Kinnunen (1999) Keskinen et al. (2002)
Krishnamurthy and Taylor 1985-86
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Non-ideal reboilers in Flowbat
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Support page
www.hut.fi/Units/ChemEng/WebFlowbat
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Input

• Based on text files
• DISTI
• UNNAME 'ROSSIN PURKKI', IPR2
• FEEDS 'F1', 'F2'
• FPLATE 36, 21
• PRODUC 'BOT', 'DIS'
• PPLATE 1, 42
• PPHASE 'LIQUID', 'LIQUID'
• PLATES 42
• PRATE 34.4, 10
• PRES 420.1, UNHEAT1, RD3.0, TMIN 300,
  TMAX 390
• KEYH1, KEYL2
• INMAX5, OUTMAX25
• END

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www.flowbat.hut.fi
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www.flowbat.hut.fi
Fill input file name
Fill email address
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WWW.flowbat.hut.fi
Send file
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Successful run
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Results by email
No big delays in getting the results
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Result files

• Output -file
• Detailed information of the simulation
• Excel-file
• Main results and profiles in Excel form

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Used at HUT

• Distillation and Reactor design courses
• Basic courses
• Supporting tool for research

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Conclusions

• We have implemented successfully Web-Flowbat
• We are willing to give the Chem. Eng. community
  the opportunity to use the software
• Start here
• www.hut.fi/Units/ChemEng/WebFlowbat
• www.flowbat.hut.fi
• www.hut.fi/Units/ChemEng/research/Publications