hi = 603,093 BtuJam.ft
2
.
o
F
N
Re
=
vi = 0,287 ms
h
io
Koefisien Transfer Panas dalam Jacket
hi
o
= hi x IDOD = 603,093 X 5 5,063
= 595,648 BtuJam.ft
2
.
o
F
pers. 12-30 McCabe Dimana
D = De
K = Konduktivitas termal air pendingin
Volume jaket =
= 9331.015,958 = 0,919 m
3
= 32,443 ft
3
V
total
=
-
32,442 =
Dj = 5,816 ft
. .
2
v D
14 ,
3 1
8 ,
023 ,
w b
pr re
nu
N N
k D
h N
2 j
0,000076xD xsf
2 2
j D
x 4
π j
xZ 2
xDj 4
π
2 s
D 0,000076xO
xsf 2
2 s
OD x
4 π
j xZ
2 s
xOD 4
π
2 j
0,000076xD x0,167
2 2
j D
x 4
π x5
2 xDj
4 π
2 ,063
0,000076x5 x0,167
2 2
5,063 x
4 π
x5 2
x5,063 4
π
D = De =
reaktor reaktor
baru
OD OD
D
2 2
= 5,063
063 ,
5 816
, 5
2 2
= 1,618 ft = 0,493 m = 19,421 in
Npr =
= 0,335
1,69x10 0,736
-4
x
= 3,71x10
-4
14 ,
3 1
8 ,
023 ,
w
Npr Nre
k De
hio
3 1
4 -
8 ,
3,71x10 023
, 0,335
618 ,
1 648
, 595
Nre N
Re
= 63.282.657,567
N
Re
=
vo = 103,955 ft
3
Jam = 0,029 ft
3
s
e. Menghitung Clean Overall Coefficient, Uc
U
C
=
o io
o io
h h
h h
= 648
, 595
093 ,
603 648
, 595
093 ,
603
=
299,6737 Btuhr.ft
2
.
o
F
f. Menghitung Design Overall Coefficient, U
D
k cp
D N
re
Rd = 0,001 hr.ft
2
.
o
Fbtu Tabel 8. Kern, 1965
Ud 1
=
Rd Uc
1
= 001
, 299,6737
1 = 0,004
Ud = 230,576 Btuhr.ft
2
.
o
F
g. Menghitung Tebal dan Lebar Jaket
Lebar jaket = 0,5 Dj
– Dt = 0,5 5,816 ft
– 5,063 ft = 0,377 ft = 0,115 m = 11,478 cm
Material = Carbon Steel SA 283 Grade C Alasan
= Sesuai digunakan untuk tekanan tinggi dan diameter besar. f
= 12.650 psi C
= 0,25 in E
= 0,85 r
j
= 2,908 ft = 34,894in
Tebal jaket tj = = 0,298 in digunakan tebal standar 38 in
Tabel 9.6. Spesifikasi RE
–20
Alat Reaktor
Kode RE-201
Fungsi Tempat mereaksikan Asam Asetat dan
Metanol dengan menggunakan katalis
Asam Sulfat Jenis
Continuous Stirred Tank Reactor CSTR Bahan Konstruksi
SA 167 Grade 11 type 316 Kapasitas
2,864 m
3
Dimesi OD
1,543 m H
total
2,402 m Tebal shell
0,375 in Tebal head
0,28 in Tebal Jacket
0,375 m Jenis Impeller
Six flat blade turbin Jumlah Impeller
1 buah Power
3,15 Hp Overall heat-transfer
230,576 Btujam.ft
2
.
o
F Coefficient
Neutralizer NE-101
Fungsi : Menetralkan H
2
SO
4
dengan NaOH pada campuran hasil keluaran Reaktor sebagai umpan ke Dekanter.
Tipe Alat : Tangki silinder berpengaduk
Bahan Konstruksi : Stainless steel SA-167 Grade 11 tipe 316.
Gambar.C.12.1. Tangki Silinder Berpengaduk
Campuran Hasil Netralisasi
NaOH Cair
a. Persamaan reaksi
Reaksi penetralan asam sulfat dengan natrium hidroksida H
2
SO
4 aq
+ 2 NaOH
aq
Na
2
SO
4 aq
+ 2 H
2
O
l
Asam Sulfat Natrium Hidroksida Natrium Sulfat Air
b. Desain Mekanis
Tabel.C.12.1. Hasil perhitungan densitas campuran bahan.
Komponen F
i
kgjam wi
massa ρ
i
kg m³
w
i
ρ
i
Asam Asetat 241.8388
0.0545 1027.44898
6 5.30923E-05 Propanol
241.8388 0.0545
788.230293 5 6.92052E-05
Propil Asetat 3326.3834
0.7503 866.387675
5 0.000866015 H
2
SO
4
4.3971 0.0010 1814.45281 5.46617E-07
Air 613.7119
0.1384 1013.63813
2 0.000136567 NaOH
Air dari
NaOH 3.5894
0.0008 1913.95612 4.2302E-07
Total 4433,3748
1.0000 0,001126209
Densitas campuran ρ
mix
=
i i
w 1
ρ
mix
= 0,0011
1 ρ
mix
= 887,9344 kgm³ = 55,4301 lbft
3
Menentukan laju alir volumetrik
F
v
=
mix i
F
F
v
= 887,9344
4433,3748 F
v
= 4,99291 m
3
jam Keterangan:
ρ
mix
= densitas campuran kg m³ F
i
= laju alir massa kgjam F
v
= laju alir massa m³ jam
c.
Perancangan Bejana Netralizer
1. Menentukan Volume Cairan
Waktu tinggal : 10 menit Arthur Chan, 2004 =
o cairan
V V
Dimana V
o
= F
v
, maka: V
cairan
= F
v
× V
cairan
= 6,99291 m
3
jam × 0,1667 jam V
cairan
= 0,832151 m
3
= 29,3528 ft
3
Keterangan: = waktu tinggal jam
V
cairan
= volume cairan dalam netralizer m
3
V
o
= F
v
= laju alir massa m
3
jam Maka volume cairan
Over design factor : 20
Peter and Timmerhaus, 4rd ed. pp.37
V
desain
= 1,2 x V
L
= 1,2 x 0,83215 m
3
= 0,99858 m
3
= 35,22333 ft
3
V
netralizer
= V
L
,
shell
+ V
dh,b
+ V
sf,b
V
L
,
shell
= volume cairan dalam shell =
4 H
D
L 2
i
V
dh
= volume dish head dalam satuan ft
3
dan D
i
, diameter shell bagian dalam satuan inchi Eq.5.11 daat dituliskan
= 0,000049D
i 3
B Y, Pers 5:88 V
sf
= volume straight flange =
4 sf
D
2 i
sehingga, V
L
=
4 H
D
L 2
i
+ 0,00004912D
i 3
+
4 sf
D
2 i
sf = 2 in = 0,1667 ft
Diambil H
L
= D
i
Mc Cabe, 1985; Geonkoplis,1994; Walas,1988; Brownell, p43, 1959
30.6934 ft
3
=
4 D
3 i
+ 0,00004912D
i 3
+ 4
1667 ,
2 i
D D
i
= 3,0757 ft = 0,9375 m = 36,9086 in H
L
= 3,0757 ft = 0,9375 m = 36,9086 in
2. Tekanan desain
P
operasi
= 1 atm = 14,6959 psi
P
hid.
=
144 h
g g
.
L c
mix
ρ
mix
= 887,9344 kg m
3
= 55,4301 lbft
3
Keterangan : g = Percepatan gravitasi = 32,174 fts
2
g
c
= Faktor konversi percepatan gravitasi = 32,1740 g
m
.cmg
f
.s
2
P
hid.
= 144
3,0757 x
1 x
55,4301
3
ft
ft lb
= 1,1839 lbin
2
= 1,1839 psi
Tekanan desain 5 -10 diatas tekanan kerja normal Couldson, vol.6, 1983, pp.637
Tekanan desain diambil 10 diatasnya. P
design
= 1,1 P
operating
+ P
hid.
= 1,1 14,6959 psi + 1,1839 psi = 17,46782 psi
3. Ketebalan Dinding Bejana
Ketebalan dinding shell : C
p E
f r
p t
d i
d s
. 6
, .
. Brownell, 1959, pers.13.1:254
dengan : t
s
: ketebalan dinding shell, in p
d
: tekanan desain, psi d
i
: diameter shell bagian dalam , in f
: nilai tegangan material, psi Brownell, 1959, App. D, p 335 digunakan material SA-167 Grade11 Type 316, f = 18.750 psi
pada 104 °F E
: efisiensi sambungan, dengan radiograp spot : 0,80 Jenis sambungan las : single-butt weld dengan backing stripe
Brownell, 1959 .Tabel 13.2 C
: korosi yang diizinkan corrosion allowance = 0,125 in
r
i
= D
i
2 = 36,9086 in 2 = 18,4543 in t
s
= in
psi psi
in psi
125 ,
17,4678 x
6 ,
80 ,
x 18750
4543 ,
18 x
17,4678
= 0,1465 in 0,1875 in
Digunakan tebal dinding standar: t
s
= 316 in = 0,1875 in
Ketebalan torisherical head
C p
2 .
E f
2 W
r p
t
d c
d d
Brownell, 1959 pers.7.77
l c
r r
3 4
1 W
Brownell, 1959 pers.7.76
Keterangan : W
: stress-intensification factor for torispherical dish r
c
: crown radius = dish radius, in r
i
: knuckle radius = inside corner radius, in OD
= ID + 2 t
s
= 36,9086 in + 2 x 0,1875 in = 37,2836 in
Dari tabel 5.7 Brownell dan Young, untuk OD 40 in diperoleh r= 40 in dan r
icr
= 2,5 W
=
5 ,
2 40
3 4
1
= 1,750 t
d
= in
psi psi
x in
psi 125
, 17,4678
x 2
, 80
, x
18750 2
750 ,
1 x
40 x
17,4678
= 0,1658 in digunakan tebal head standar = 316 in = 0,1875 ft
Dari Tabel 5.8 Brownell and Young, 1959 diperoleh sf = 1
2 1
- 2 in. Digunakan straight flange s
f
= 2 in Brownell Young, table 5.8:93
4. Tinggi Bejana
Tinggi shell, Hs = 3,0757 ft Tinggi dish, dihitung dengan dimensi berikut:
OD
ID A
B icr
b = tinngi dish
a t
r
OA
sf
C
Gambar 12.2. Hubungan dimensi untuk flanged and dish heads Brownell and Young, Tab. 5.8:87
` AB
=
icr 2
ID
=
5 ,
2 2
36,9086 in
in
= 15,9543 in BC
= r – i
cr
= 40 in - 2,5 in = 37,5
b =
2 2
AB BC
r
= 40 in
2 2
15,9543 5
, 37
= 6,0631 in tinggi dish ;
H
D
= OA = t
d
+ b + s
f
= 0,1685 in + 6,0631 in + 2 in = 8,2289 in
Tinggi total Netralizer =2xtinggi tutup H
D
+tinggi shell H
s
1,3 0,75
D Z
I I
= 2 x 8,2289 in + 36,9086 in = 53,3680 in
5. Desain Sistem Pengaduk
D
I
B a
f f
l e
B a
f f
l e
Z
I
H
t
I
J
D
t
D
d
W
Gambar 12.3. Basis perancangan tangki berpengaduk
a. Dimensi Pengaduk
Digunakan impeler dengan jenis :Disc six flat -blade open turbin dengan geomerti: Genkoplies, table 3.4-1
Brown, 1950 Brown, 1950
12 J
D
t
Wallas, 1990 8
W D
I
Geankoplis, 1993 3
1 D
D
t I
J 0,15
0,1 C
Geankoplis, 1993
I I
D 0,2
t
Brown, 1950 J
0,5 t
b
Brown, 1950
I
D 2
1 1
Offset
Wallas, 1990
J 6
1 2
Offset
Wallas, 1990 D
d
= 23 D
I
Geankoplis, 1993 Keterangan :
D
I
= Diameter impeller, m D
t
= Diameter tangki, m Z
I
= Tinggi impeller dari dasar tangki, m J
= Lebar baffle, m W
= Lebar impeller, m C
= Clearence atau gap antara baffle dengan dinding, m D
d
= Diameter batang penyangga impeller, m t
I
= Tebal impeller, m t
b
= Tebal baffle, m Offset
1 = Jarak baffle dari dasar tangki, m
Offset 2
= Jarak baffle dari permukaan cairan, m
Jadi, dimensi pengaduk adalah : D
I
= 13 36,9086 in = 12,3029 in = 0,3125 m
Z
I
= 1,3 12,3029 in = 15,9937 in = 0,4062 m
J = 112 36,9086 in
= 3,0757 in = 0,0781 m W
= 18 12,3029 in = 1,5379 in = 0,0391 m
C = 0,15 3,0757 in
= 0,4614 in = 0,0117 m t
I
= 0,2 12,3029 in = 2,4606 in = 0,0625 m
t
b
= 0,5 3,0757 in = 1,5379 in = 0,0391 m
Offset 1= 12 12,3029 in
= 6,1514 in = 0,1562 m Offset
2= 16 3,0757 in = 0,5126 in = 0,0130 m
D
d
= 23 12,3029 in = 8,2019 in = 0,2083 m
