| Name: |
14eq1 - Three stage, two component
distillation column |
| Source: |
Cutlip, M. B. and Shacham,
M, Problem Solving in Chemical |
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Engineering with Numerical
Methods (2nd Ed.), Prentice Hall
Inc., |
| Reference/s |
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| Model: |
14 implicit equations, indep.
variables x11, x12, x13, x21, x22, x23, t1, t2, t3, tf, t0, V1,
V2 and V3 |
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Average difficulty level |
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Constraints: All the variables
(except the temperatures: ti ) are nonnegative |
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Discontinuities: Undefined
for some negative temperature (ti) values |
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Initial estimates: 1.(0.5,
0.4, 0.3, 0.3, 0.4, 0.5, 145, 190, 210, 200, 200, 1, 1, 1) ; |
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2. (0.1, 0.1, 0.1,0.1, 0.1,
0.1,100, 100, 100, 100, 100, 5, 5, 5) |
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| Solved by |
Shacham, M., POLYMATH 5.1,
build 19, April 18, 2001 |
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| Model Eqs. |
Three stage, two component
distillation column |POLVER05_1 |
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EXCEL
FILE |
f(x11)=-((V1-L0)*k11+L1)*x11+V2*k12*x12
# |
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TEXT
FILE |
f(x12)=L1*x11-(V2*k12+L2)*x12+V3*k13*x13+z1*F
# |
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POLYMATH
FILE |
f(x13)=L2*x12-(V3*k13+B)*x13
# |
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f(x21)=-((V1-L0)*k21+L1)*x21+V2*k22*x22
# |
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f(x22)=L1*x21-(V2*k22+L2)*x22+V3*k23*x23+z2*F
# |
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f(x23)=L2*x22-(V3*k23+B)*x23
# |
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f(t1) = k11*x11+k21*x21-1
# |
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f(t2) = k12*x12+k22*x22-1
# |
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f(t3) = k13*x13+k23*x23-1
# |
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f(tf) = k1f*z1+k2f*z2-1 # |
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f(t0) = k10*k11*x11+k20*k21*x21-1
# |
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f(V1) = -V1*hv1+V2*hv2-L1*hl1+L0*h0
# |
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f(V2) = -V2*hv2+V3*hv3+hf+L1*hl1-L2*hl2
# |
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f(V3) = -V3*hv3+Q+L2*hl2-L3*hl3
# |
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L0=V1-D # |
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L1=V2-D # |
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L2=V3+F-D # |
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L3=B # |
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hl1 = t1*(29.6+0.04*t1)*x11+t1*(38.5+0.025*t1)*x21
# |
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hv1=(8003+t1*(43.8-0.04*t1))*k11*x11+(12004+t1*(31.7+0.007*t1))*k21*x21
# |
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hl2=t2*(29.6+0.04*t2)*x12+t2*(38.5+0.025*t2)*x22
# |
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hv2=(8003+t2*(43.8-0.04*t2))*k12*x12+(12004+t2*(31.7+0.007*t2))*k22*x22
# |
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hl3=t3*(29.6+0.04*t3)*x13+t3*(38.5+0.025*t3)*x23
# |
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hv3=(8003+t3*(43.8-0.04*t3))*k13*x13+(12004+t3*(31.7+0.007*t3))*k23*x23
# |
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hf = tf*(29.6+0.04*tf)*z1+tf*(38.5+0.025*tf)*z2
# |
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h0 = t0*(29.6+0.04*t0)*k10*k11*x11+t0*(38.5+0.025*t0)*k20*k21*x21
# |
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k11=10^(6.80776-935.77/((t1-32)*5/9+238.789))/P
# |
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k12 = 10^(6.80776-935.77/((t2-32)*5/9+238.789))/P
# |
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k13=10^(6.80776-935.77/((t3-32)*5/9+238.789))/P
# |
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k21 = 10^(6.85296-1064.84/((t1-32)*5/9+232.012))/P
# |
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k22=10^(6.85296-1064.84/((t2-32)*5/9+232.012))/P
# |
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k23=10^(6.85296-1064.84/((t3-32)*5/9+232.012))/P
# |
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k1f = 10^(6.80776-935.77/((tf-32)*5/9+238.789))/P
# |
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k2f = 10^(6.85296-1064.84/((tf-32)*5/9+232.012))/P
# |
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k10 = 10^(6.80776-935.77/((t0-32)*5/9+238.789))/P
# |
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k20 = 10^(6.85296-1064.84/((tf-32)*5/9+232.012))/P
# |
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F=1 # |
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z1 = 0.40 # |
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z2 = 1-z1 # |
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B=0.75 # |
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D=0.25 # |
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P=760*120/14.7 # |
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Q = 10000 # |
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y11 = k11*x11 # |
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y12 = k12*x12 # |
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rec = y11*D/(z1*F) # |
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x11(0)=0.5 |
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x12(0)=0.4 |
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x13(0)=0.3 |
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x21(0)=0.3 |
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x22(0)=0.4 |
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x23(0)=0.5 |
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t1(0)=145 |
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t2(0)=190 |
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t3(0)=210 |
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tf(0)=200 |
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t0(0)=200 |
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V1(0)=1 |
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V2(0)=1 |
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V3(0)=1 |
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| Variable/function values |
Variable |
Value |
f(x) |
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x11 |
0.5 |
0.087 |
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x12 |
0.4 |
0.037 |
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x13 |
0.3 |
-0.051 |
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x21 |
0.3 |
-0.031 |
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x22 |
0.4 |
0.258 |
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x23 |
0.5 |
-0.023 |
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t1 |
145 |
-0.507 |
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t2 |
190 |
-0.220 |
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t3 |
210 |
-0.126 |
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tf |
200 |
-0.002 |
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t0 |
200 |
-0.305 |
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V1 |
1 |
6070.4 |
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V2 |
1 |
3212.9 |
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V3 |
1 |
742.2 |
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D |
0.25 |
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L0 |
0.75 |
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L1 |
0.750 |
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B |
0.75 |
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hl1 |
4398.9 |
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P |
6204.1 |
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hl2 |
6114.2 |
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k21 |
0.2806 |
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hl3 |
6987.8 |
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k22 |
0.5376 |
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z1 |
0.4 |
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k23 |
0.6955 |
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k20 |
0.6128 |
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k11 |
0.817 |
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k12 |
1.411 |
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k13 |
1.753 |
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hv1 |
6927.7 |
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hv2 |
12331.3 |
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hv3 |
14716.8 |
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k1f |
1.5759 |
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k2f |
0.6128 |
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k10 |
1.5759 |
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F |
1 |
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z2 |
0.6 |
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hf |
8228 |
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L3 |
0.75 |
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L2 |
1.75 |
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h0 |
5288.1 |
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Q |
10000 |
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y11 |
0.4083 |
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y12 |
0.5645 |
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rec |
0.2552 |
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| Solution |
Variable |
Value |
f(x) |
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x11 |
0.57902594925514 |
1.11E-16 |
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x12 |
0.39569120229748 |
9.99E-16 |
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x13 |
0.27186578944464 |
-1.11E-15 |
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x21 |
0.42097405074479 |
0 |
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x22 |
0.60430879770252 |
3.33E-16 |
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x23 |
0.72813421055536 |
-2.22E-16 |
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t1 |
186.378525897475 |
6.66E-16 |
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t2 |
200.526868526979 |
0 |
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t3 |
211.486095297259 |
1.110E-15 |
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tf |
200.167501447086 |
0 |
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t0 |
169.064015709595 |
0 |
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V1 |
1.08137588467567 |
-3.64E-12 |
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V2 |
1.06683987591090 |
1.82E-11 |
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V3 |
1.04952829661125 |
-2.18E-11 |
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D |
0.25 |
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L0 |
0.83137588467567 |
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L1 |
0.81683987591090 |
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B |
0.75 |
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hl1 |
7385.230868740510 |
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P |
6204.081632653060 |
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hl2 |
8258.041508211440 |
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k21 |
0.51213933009160 |
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hl3 |
8931.054498916270 |
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k22 |
0.61698043668574 |
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z1 |
0.4 |
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k23 |
0.70841654598484 |
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k20 |
0.61413708445032 |
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k11 |
1.35469339962803 |
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k12 |
1.58495637623241 |
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k13 |
1.78094374630232 |
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hv1 |
15505.2876150983 |
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hv2 |
16469.3793109932 |
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hv3 |
17305.1918210042 |
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k1f |
1.57879437332452 |
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k2f |
0.61413708445032 |
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k10 |
1.10605654005438 |
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F |
1 |
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z2 |
0.6 |
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hf |
8235.9303882639 |
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L3 |
0.75 |
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L2 |
1.79952829661125 |
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h0 |
6290.0604895603 |
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Q |
10000 |
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y11 |
0.78440263166929 |
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y12 |
0.62715329410047 |
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rec |
0.49025164479331 |
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| Additional information |
Some algorithms do not converge
from initial guess 2 |