Operation of Divided Wall (Petlyuk) Column at energy lower than minimum energy

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Operation of Divided Wall (Petlyuk) Column at
energy lower than minimum energy

• Ambari Khanam
  Supervisor Sigurd Skogestad
• Department of Chemical Engineering
• Norwegian University of Science and Technology
  (NTNU)
• November 7, 2012

khanam_at_stud.ntnu.no
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Outline

• Introduction to DWC
• Operation at lower enery

Motivation

• Around more than100 Divided Wall columns already
  in use.
• Growing Economy,personal usage of energy
  increasing day by day,limted energy resources,
  CO2 Reduction compliances.
• Divided wall column can save upto 20-30 of
  energy (for 3 products and even more in other
  cases)
• Also saves Capital Costs

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Schematic diagram of 3-product Petlyuk Column and
Divided Wall Column
Background

• The project work is related to most likely
  situations in Industrial practice.
• - The column is designed for optimal
  operation
• - Optimal Energy/close to Vmin for the given
  product specifications
• - Actual avialable energy lesser (in the
  range of 70-95)
• - Effect on product purities in all three
  streams
• - Minimize the impurities (the objective
  function)

Operation
Assignments
Mode 2 Jmin. impurity
Mode1 JV
Mode 2,With fixed boilup rate V (close to
Vmin) U RL, RV,L,S and V(fixed) U RL,L, S,
RV(fixed,-20) and V(fixed) Fmincon in Matlab
for optimization
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Results and remaining job
Mole fraction of B versus V(Boilup)
Mole fraction of A versus V(Boilup)
Plot the compositions profile keeping one U
varying at a time U RL, RV,L,S and V(fixed), U
RL,L, S, RV(fixed,-20) and V(fixed)
Run the model for DWC in matlab and following
optimal values are obtained (Model prepared by
Dwivedi)
XA and XB for different prices