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Unformatted text preview: energy balance can be formulated as: [Accumulation of total energy ] = [Input of total energy ]  [Output of total energy ]
time time time [Energy supp lied by steam ] +
time Or = Fc [ d Hc p , B , av (T  T f ) re
dt in
p F , av (T  T f ) , re Bc p , B , av (T  T f )  D p , D , av (T  T f ) + l ] + Q [c re
re Assuming T e f = 0 then,
R [ d Hc p , B , av T dt = Fc p , F , av Tin  Bc p , B , av T  D[ p , D , av T + l ] + Q c Where, l is the mo lar heat of vaporization and T = T . At steadystate, this reduces to,
in
Q = D l
Overall material balance yields, d ( H M ) = M F  M D  M B d t Where, HM is the mass ho ldup of the unit and Mi are the mass flowrates. We can express the mass flowrate as, for example:
M F = MW Fx F + MWC F (1  x F ) = F [MWC + x F ( W  MWC ) M A ]
A Where, MWi is the mo lecular weight of component i This results in the fo llowing material balance (mo lar balance) expressio n:
d ( H [MW + x B ( MW A  MW ) ) C C ]
= F [MW + x F ( MW A  MW ) C C ]
d t [ C  B MW + x B ( MW A  MW ) C ] [ C  D MW + x D ( MW A  MW ) C ]
The component balance for component A yields, d ( Hx B MW ) A = Fx F MW  Bx MW  Dx D MW A B A...
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 Fall '08
 Hjortso,M
 Chromatography, pH

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