P
desain
= 1,1 P
operasi
+ P
hidrostatik
= 1,1 14,696 + 4,625 psi = 21,253 psi = 1,446 atm
c. Bahan Konstruksi
Material = Stainless Steel SA 167 Grade 11 type 316 Brownell:342 Alasan = Sesuai digunakan untuk tekanan tinggi dan diameter besar.
f = 18.750 psi
C = 0,25 in
E = 0,85
d. Menghitung Tebal Shell
� =
� −0,6
+ Brownell Young, 1959:45
Keterangan : t
s
= Tebal shell in P = Tekanan operasi psi
f = Allowable stress psi r
i
= Jari-jari shell in E = Efisiensi pengelasan
C = Faktor korosi in t
s
=
25 ,
21,253 0,6
- 0,85
750 .
18 2
114 21,253
= 0,326 in digunakan tebal standar 38 in = 0,375 ft
e. Diameter Luar Shell OD
s
OD
s
= ID + 2. t
s
= 118 in + 2 38 in = 118,75 in
= 9,56 ft = 2,91 m
f. Menentukan tinggi reaktor
Tinggi total reaktor = tinggi shell H
s
+ 2 x tinggi tutup
1. Tinggi Shell H
s
Volume desain reaktor merupakan penjumlahan volume shell, volume head
and bottom torispherical, dan volume straight flange head and bottom
. V
r
= V
shell
+ V
head atas
+ V
head bawah
+ V
straight flange
F.9
169,844 ft
3
=
4 H
D I
π
s 2
+
4 sf
D I
π 2
2
+ 2
0,000076 I
3
D
H
s
= 117,87 in Diambil H
s
= 118 in = 9,5 ft = 2,89 m
2. Tinggi Tutup OA
OA = t
h
+ b + sf Keterangan :
b = Depth of dish inside, in t
h
= tebal torispherical head, in sf = straight flange, in
a. Menghitung tebal head
C P
. 2
, E
. f
. 2
V .
ID .
P t
h
Brownell Young,pers. 7.77,1959
k 2
6 1
V
2
Brownell Young,pers. 7.76,1959 Keterangan :
V = stress-intensification factor k = ,
b a
mayor-to-minor-axis ratio
a =
2 ID
= 2
114 = 57 in
b = 5
, 28
4 114
4
ID
in
k = 2
5 ,
28 57
V = 1
2 2
6 1
2
t =
25 ,
2 ,
253 ,
1 2
85 ,
18.750 2
1 114
253 ,
1 2
= 0,326 in Digunakan tebal plat standar =
3 8
in
OD
ID A
B icr
b
a t
r O
A sf
Gambar C.35. Dimensi torisherical flanged and dish Heads
b. Tinggi Tutup OA
Tinggi head and bottom torrispherical adalah : OA
= t
h
+ b + sf = 0,375 in + 28,5 in + 2 in
= 30,875 in = 2,57 ft = 0,78 m
3. Tinggi Cairan H
L,s
Tinggi cairan di shell H
L,S
= H
L
– OA = 118 in
– 30,875 in = 83,125 in
= 6,93 ft = 2,11 m
4. Menghitung Tinggi Total Reaktor
Tinggi total reaktor = tinggi shell H
s
+
OA atau
tutup tinggi
2
= 9,5 ft + 2 x 2,57 ft = 14,65 ft = 4,46 m
5. Perancangan Sparger
- Menentukan Koefisien Difusifitas D
AL
Proses difusi terjadi di dalam fasa cair. Persamaan yang digunakan adalah :
Coulson Vol 6, 1989; hal 255, Pers 8.22
Keterangan : Φ
: Association parameter = 1 M
: Berat molekul larutan, kg kgmol = 267,9886 T
: Temperatur, K = 453 K μ
: Viskositas larutan, kgm.det = 9,7467 x 10
-5
V
m
: Volume molal zat terlarut, m
3
kmol Berdasarkan Tabel 8.6 Coulson Vol 6, 1989; hal 256
V
m
H
2
= 0,0143 m
3
kmol
Difusifitas HCHO dalam Urea solution : D
AL
= 1,1428 x 10
-7
m
2
det
-
Menentukan Δρ ρ
gas
pada T = 343 K dan P = 1 atm Δρ
= 766,1451-0,3228 kgm
3
= 765,8223 kgm
3
- Menghitung Surface Tension
Pers 8.23, hal 258; Coulson Vol 6, 1989 Keterangan :
σ
L
: Surface tension, dynecm P
ch
: Sudgen’s parachor
ρ
L
: Densitas cairan, kgm
3
ρ
v
: Densitas saturated vapor, kgm
3
0,6 m
0,5 18
AL
V μ
T M
10 .
3 ,
117 D
12 4
v L
ch L
10 M
ρ ρ
P
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