$Title    Mixed-integer linear model for synthesis of distillation sequence for 4 components

SETS
K         Potential distillation columns /1*10/

SCALARS
CC        Cost of cooling water ($*J-1*yr-1) /1.3E-6/
CH        Cost of steam ($*J-1*yr-1) /34E-6/
FIN       Inlet flow to the system (kmolh-1) /1000/

PARAMETERS
A(K)      Fixed term of investment cost (k$*yr-1) /1 145,2 52,3 76,4 38,5 66,6 125,7 44,8 58,9 37,10 112/
B(K)      Variable term of investment cost (k$*h*kmol-1*yr-1) /1 0.42,2 0.12,3 0.25,4 0.14,5 0.21,6 0.78,7 0.11,8 0.19,9 0.08,10 0.39/
H(K)      Heat duty coefficients (kJ*h*kmol-1) /1 28E3,2 42E3,3 54E3,4 40E3,5 47E3,6 24E3,7 39E3,8 44E3,9 36E3,10 22E3/

VARIABLE
COST      Total annualized cost (k$*yr-1)

BINARY VARIABLES
Y(K)      Selects distillation column K

POSITIVE VARIABLES
F(K)      Flow going into column K (kmolh-1)
Q(K)      Heat duty of column K (kJ)

EQUATIONS
OBJECT    Objective function
MB1       Equation 1 of mass balance
MB2       Equation 2 of mass balance
MB3       Equation 3 of mass balance
MB4       Equation 4 of mass balance
MB5       Equation 5 of mass balance
MB6       Equation 6 of mass balance
HD(K)     Computes heat duty of column K
NZ(K)     Non-zero flow in column K only if it selected in the solution
;

OBJECT..
MB1..
MB2..
MB3..
MB4..
MB5..
MB6..
HD(K)..
NZ(K)..   


OPTION Solprint=Off;

Model Sequence using /all/;
SOLVE Sequence using MIP minimizing COST;

Display Y.l,F.l,Q.l;