Yenny : Pra Rancangan Pabrik Pembuatan Etilen Oksida dengan Katalis Perak, 2007 USU Repository © 2008
Luas permukaan luar a ″ = 0,1963 ft
2
ft Tabel
10, Kern Jumlah tube,
386,8272 ft
ft 0,1963
ft 16
ft 1214,9470
a L
A N
2 2
t
= ×
= ×
=
buah Dari Tabel 9, hal 842, Kern 1965, nilai yang terdekat adalah 394 tube
dengan ID shell 25 in. b. Koreksi U
D
2 2
t
ft 1237,4752
ft ft
0,1963 394
ft 16
a N
L A
= ×
× =
× ×
=
F ft
jam Btu
39,2718 F
120,1902 ft
1237,4752 Btujam
77 5840990,05
t A
Q U
2 2
D
° ⋅
⋅ =
° ×
= ⋅
=
Fluida dingin: air, tube
3 Flow area tube, a
t
′ = 0,334 in
2
Tabel 10, Kern
n 144
t a
t N
t a
× ×
=
Pers. 7.48,
Kern
2
ft 0,1523
6 144
334 ,
394 t
a =
× ×
=
4 Kecepatan massa
t a
W t
G =
Pers. 7.2,
Kern
2
ft jam
m lb
48 1067001,25
0,1523 7
162515,158 t
G ⋅
= =
5 Bilangan Reynold
Pada t
c
= 100,4 °F
μ = 0,75 cP = 1,8143 lb
m
ft
2
⋅jam Gbr. 15,
Kern Dari Tabel 10, Kern 1965, untuk ¾ in OD, 18 BWG, diperoleh
ID = 0,652 in = 0,0543 ft
Yenny : Pra Rancangan Pabrik Pembuatan Etilen Oksida dengan Katalis Perak, 2007 USU Repository © 2008
t G
ID t
Re ×
=
Pers. 7.3,
Kern
1,8143 48
1067001,25 0,0543
t Re
× =
= 31953,3352 6
Taksir j
H
dari Gambar 24, Kern 1965, diperoleh j
H
= 95 7
Pada t
c
= 100,4°F c = 0,99 Btulbm°F
Gbr 3, Kern
k = 0,364 Btujam.ft°F Tabel 5,
Kern
1,7025 364
, 8143
, 1
1
3 1
3 1
= ⎟
⎠ ⎞
⎜ ⎝
⎛ × =
⎟ ⎠
⎞ ⎜
⎝ ⎛ ⋅
k c
μ
8
3 1
⎟ ⎠
⎞ ⎜
⎝ ⎛ ⋅
× ×
= k
c D
k j
h
H t
i
μ φ
Pers. 6.15, Kern
1083,5317 7025
, 1
0,05433 0,364
95 =
× ×
=
t i
h
φ
9
0,75 0,652
1083,5317 OD
ID ×
= ×
=
t i
t io
h h
φ φ
= 941,9502 10
Karena viskositas rendah, maka diambil
φ
t
= 1
t t
io
h
φ φ
× =
io h
h
io
= 941,9502 × 1 = 941,9502
Fluida panas: shell, bahan
3 ′ Flow area shell
T
P 144
B C
s D
s a
× ×
× =
Pers. 7.1,
Kern D
s
= Diameter dalam shell = 25 in B
= Baffle spacing = 15 in
P
T
= Tube pitch = 1 in C
′ = Clearance = P
T
– OD = 1,25 – 1 = 0,25 in
0,6510 1
144 5
1 25
, 25
s a
= ×
× ×
=
ft
2
Yenny : Pra Rancangan Pabrik Pembuatan Etilen Oksida dengan Katalis Perak, 2007 USU Repository © 2008
4 ′ Kecepatan massa
s a
w s
G =
Pers. 7.2,
Kern
2
ft jam
m lb
101647,621 0,6510
66176,8366 s
G ⋅
= =
5 ′ Bilangan Reynold
Pada T
c
= 288,5 °F
μ = 0,022 cP = 0,0532 lb
m
ft
2
⋅jam Gbr.
15, Kern
Dari Gambar 28, Kern 1965, untuk ¾ in dan 1 triangular pitch, diperoleh d
e
= 0,73 in. D
e
= 0,7312 = 0,0608 ft
s G
e D
s Re
× =
Pers. 7.3,
Kern
1 116188,282
0,0532 101647,621
0,0608 s
Re =
× =
6 ′ Taksir j
H
dari Gambar 28, Kern 1965, diperoleh j
H
= 210
7 ′ Pada T
c
= 288,5 °F
c = 0,22 Btulb
m
F Gbr 3,
Kern k = 0,0156 Btujam.ft.
o
F Tabel
5, Kern
0,9088 0156
, 022
, 22
,
3 1
3 1
= ⎟
⎠ ⎞
⎜ ⎝
⎛ ×
= ⎟
⎠ ⎞
⎜ ⎝
⎛ ⋅ k
c μ
8 ′
3 1
⎟ ⎠
⎞ ⎜
⎝ ⎛ ⋅
× ×
= k
c e
D k
j s
o h
H
μ φ
Pers. 6.15, Kern
48,9396 0,9088
0,0608 0,0156
1 2
s o
h =
× ×
=
φ
9 ′ Karena viskositas rendah, maka diambil φ
s
= 1
s s
l o
h o
h
φ
× =
h
o
= 48,9396 × 1 = 48,9396
10 Clean Overall coefficient, U
C
Yenny : Pra Rancangan Pabrik Pembuatan Etilen Oksida dengan Katalis Perak, 2007 USU Repository © 2008
F ft
Btujam 46,5225
48,9396 941,9502
48,9396 941,9502
h h
h h
U
2 o
io o
io C
° ⋅
⋅ =
+ ×
= +
× =
Pers. 6.38, Kern 11
