Abubakar Adeni Assg4 Permas02
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Abubakar Adeni
1106068516
Teknik Kimia
9.15 A solution of Acetone and Water containing 50 wt% each is to be continuously
fractionated at standard atmospheric pressure at rate 4000 kg/h. The distillate
product is to contain 95 wt % acetone , the residue 0.5%. The feed will be 30 mol%
vaporized before it enters the tower. A total condenser will be used, and reflux will be
returned at the bubble point.
T X1 Y1 73.26 0.47 0.81
Deg C 72.85 0.48 0.82
100.00 0.00 0.00 72.43 0.49 0.83
99.26 0.01 0.04 72.02 0.50 0.83
98.53 0.02 0.07 71.62 0.51 0.84
97.80 0.03 0.10 71.22 0.52 0.84
97.08 0.04 0.14 70.83 0.53 0.85
96.37 0.05 0.17 70.44 0.54 0.86
95.67 0.06 0.20 70.05 0.55 0.86
94.98 0.07 0.22 69.67 0.56 0.87
94.30 0.08 0.25 69.30 0.57 0.87
93.62 0.09 0.28 68.92 0.58 0.88
92.95 0.10 0.30 68.55 0.59 0.88
92.29 0.11 0.33 68.19 0.60 0.89
91.64 0.12 0.35 67.83 0.61 0.8991.00 0.13 0.37 67.47 0.62 0.90
90.36 0.14 0.40 67.12 0.63 0.90
89.73 0.15 0.42 66.77 0.64 0.90
89.11 0.16 0.44 66.43 0.65 0.91
88.50 0.17 0.46 66.09 0.66 0.91
87.89 0.18 0.48 65.75 0.67 0.92
87.29 0.19 0.49 65.41 0.68 0.92
86.70 0.20 0.51 65.08 0.69 0.92
86.12 0.21 0.53 64.76 0.70 0.93
85.55 0.22 0.55 64.43 0.71 0.93
84.98 0.23 0.56 64.11 0.72 0.93
84.42 0.24 0.58 63.79 0.73 0.94
83.86 0.25 0.59 63.48 0.74 0.94
83.32 0.26 0.60 63.17 0.75 0.94
82.77 0.27 0.62 62.86 0.76 0.95
82.24 0.28 0.63 62.56 0.77 0.95
81.71 0.29 0.64 62.26 0.78 0.95
81.19 0.30 0.66 61.96 0.79 0.95
80.68 0.31 0.67 61.66 0.80 0.96
80.17 0.32 0.68 61.37 0.81 0.96
79.67 0.33 0.69 61.08 0.82 0.96
79.18 0.34 0.70 60.79 0.83 0.97
78.69 0.35 0.71 60.51 0.84 0.97
78.20 0.36 0.72 60.23 0.85 0.97
77.73 0.37 0.73 59.95 0.86 0.9777.26 0.38 0.74 59.67 0.87 0.97
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76.79 0.39 0.75 59.40 0.88 0.98
76.33 0.40 0.76 59.12 0.89 0.98
75.88 0.41 0.77 58.86 0.90 0.98
75.43 0.42 0.78 58.59 0.91 0.98
74.99 0.43 0.78 58.33 0.92 0.99
74.55 0.44 0.79 58.06 0.93 0.99
74.11 0.45 0.80 57.81 0.94 0.9973.69 0.46 0.81 57.55 0.95 0.99
57.29 0.96 0.99
57.04 0.97 0.99
56.79 0.98 1.00
56.54 0.99 1.00
56.30 1.00 1.00
a) Determine the product rates, kg/h.
b) Determine the minimum reflux ratio.
c) Determine the minimum number of theoritical trays, graphically and by means
of eq.(9.85)
d) Determine the number of theoritical trays required at reflux ratio equal to
twice the minimum and the position of feed tray.
e) Estimate the overall tray efficiency of a sieve-tray tower of conventional
design and the number of real trays.
f) Using the distillate temperature as the base temperature, determine the
enthalpy of the feed, the products, and the vapor entering the condenser.
Determine the heat loads of the condenser and reboiler. Latent and spesific
heats are available in The Chemical Engineers Handbook, 5th
ed., pp. 3-116
and 3-129.
Penyelesaian
Diketahui:
F = 4000 kg/h GF = 30%
Acetone : zF = 50 wt% Water : zF = 50 wt%
xD = 95 wt% xD = 5 wt%
xW = 0,5 wt% xW= 99,5 wt%
Mr = 58 gr/mol Mr = 18 gr/mol
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5. Membuat garis operasi enriching (hubungkan titik pertemuan garis operasi feed dan
garis kesetimbangan dengan titik pertemuan garis distilat dan diagonal)
Titik potong antara feedline dengan kurva kesetimbangan dan titik akhir
X2 = 0.157
Y2 = 0.424
X1 = 0.95
Y1 = 0.95
! !!
!!
!!
= ! !!!!
!!
! 0.95
0.424 0.95= ! 0.95
0.157 0.95
! = !.!!"!+ !.!"#6. Menentukan rasio reflux minimum
!!
!!+ 1
= 0.38
0.855
!!+ 1
= 0.38
!!= 1,67
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C. Determine the minimum number of theoritical trays, graphically and by means of
eq.(9.85)
Menentukan jumlah kolom teoritis
!!+ 1 =
log0.855
1 0.855
1 0.0015
0.0015
log5.532
!!+ 1 = 4.83
!!= 3.83 4
y = 1.5362x3 - 3.5798x2 + 3.034x + 0.0264
0.00
0.20
0.40
0.60
0.80
1.00
0.00 0.20 0.40 0.60 0.80 1.00
Y
X
x-y Chart
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Berdasarkan grafik diperoleh minimum tray sebanyak 5 Tray
D. Determine the number of theoritical trays required at reflux ratio equal to twice the
minimum and the position of feed tray.
Reflux ratio minimum = 1.67. Sedangkan apabila reflux rationya menjadi dua kali
reflux ratio minimum, intercept garis operasi enrichingnya menjadi (R= 2 Rm)
! =!
! + 1! + !"
! + 1
! =3,34
3,34+ 1! + 0.855
3,34+ 1
! = 0.769! + 0.196
Untuk mendapatkan Stripping line mencari titik potong antara enriching line dengan
feed line sehingga didapatkan seperti persamaan berikut ini :0.769! + 0.196 = 2.33! + 0.79
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Sehingga didapat :
X : 0.1917 Y :0,3434
Berdasarkan grafik yang didapatkan, jumlah tray yang dibutuhkan pada saat R = 2R
adalah 7 tray dan feed masuk pada tray ke 3.
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8
e) Estimate the overall tray efficiency of a sieve tray tower of conventional design and
the number of real trays.
Dari grafik kita dapat menghitung efisiensi tray dengan terlebih dahulu menghitung
nilai av x L. Nilai yang diketahui adalah :
av =5,532
L = 6,03 x 10-4
sehingga didapat av x L= 3,33 x 10-3. Jika dimasukkan ke grafik maka didapat nilai
Eo (Efisiensi trays ) sebesar 0,51.
Dari nilai efisiensi diatas maka dapa dihitung real trays dengan persamaan berikut ini
!!=
!"#$%&!"!"#$%!"#$%!"#$%!"&!"#$%&!"!"#$!"#$%!"!"#$%&
0.38 =7
!"#$%&!"!"#$!"#$%!"#$%!"&= 18,42 18
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Jadi jumlah trays pada kenyataannya adalah 18
f) Using the distillate temperature as the base temperature, determine the enthalpy of
the feed, the products, and the vapor entering the condenser. Determine the heat loads
of the condenser and reboiler. Latent and spesific heats are available in The
Chemical Engineers Handbook, 5th
ed., pp. 3-116 and 3-129.
Heat loads of the condenser (QC)
QC = D [(R + 1) HG1 R HL0 HD]
Heat loads of the reboiler (QB)
QB = D HD + W HW + QC + QL F HF
Diketahui dari pembahasan sebelumnya:
F = 145,595 kmol/h
D = 40,139 kmol/h
W = 105,455 kmol/h
R = 2 Rm = 3.34
q = 0.7
Basis: 1 jamfeed
Untuk aceton (A)
Untuk temperature 56,3 C, didapatkan:
Enthalpy of vaporization (Hvap) = 29,121 kj/mol
AV = (xFxf) + (yFyf)AV = (0.237 x 29,121 kJ/mol) + (0.763 x 40,706 kJ/mol)
= 37,960 kJ/mol
q = (H Cp dT)/AV
0.7 (J/mol K)= (H x 124.700 J/mol K) / 37,960 x 1000 J/mol
H = 213.087 J/mol