Equipments Design
PO/Styrene Plant
Prof. M. Fahim
Eng. Yousef Ismael
Done By:
Salem Alkanaimsh
Agenda





Reactor Design.
Heat Exchangers Design.
Distillation Columns Design.
Pumps Design.
Compressors Design.
Reactor Design


1.
2.



Chemical reactors are the heart of chemical
processes.
Reactors can be divided into:
Batch reactors.
 kt
C
t

C
e
A
A
o
Continues reactors.
CSTR.
n 1
C A t   C A o 1  n  1kCA o t
PFTR.
Example: Petroleum Refinery.



1
1 n
Reactor Design
Finding The rate equation:
Design Equation
o 
Fo
o
 FAo 
1  x 
 rA  k 
 o 
 rA  kCA  kCA o 1  x 
FAo  FA
V
 rA
Reactor Design
Thickness of Reactor
Diameter and length of reactor
V  0.25D 2 L
L

Assume  4 
D

V  D 3
Area  2r r  L 
D
rj 
2
t
Pr j
SE j  0.6 P
 Cc
Where;
t: thickness of reactor.
P: internal pressure .
ri: radius of the vessel .
Ej: joint efficiency .
S: stress of carbon steal .
Cc: corrosion allowance
Equipment Name
Reactor
Objective
Oxidation Of Ethyl Benzene.
Equipment Number
CRV-100
Designer
Eng. Salem Alkanaimsh
Type
CSTR Reactor
Location
Ethyl benzene oxidation section
Material of Construction
Carbon Steel
Insulation
Foam Glass
Cost
851796
Operating Condition
Operating Temperature (oC)
190
Volume of Reactor (m3)
784.376
Operating Pressure (psia)
50
Catalyst Type
-
Feed Flow Rate (mole/s)
2226
Catalyst Density (Kg/m3)
-
Conversion (%)
1.908
Catalyst Diameter (m)
-
Weight of Catalyst (Kg)
-
Reactor Height (m)
25.195
Number of Beds
-
Reactor Diameter (m)
6.29875
Height of Bed/s (m)
-
Reactor Thickness (m)
0.085
Height of Reactor (m)
25.195
Cost ($)
851796
Heat Exchanger Design


1.
2.
3.

1.
2.
Definition.
Service.
Exchanger.
Condenser.
Heater.
Type.
Shell and tube.
Air cooled HX.
Shell and Tube HX
1.

2.
3.
Tubes.
Pattern of Tubes.
Shell and nozzle.
Baffles.
Shell & Tube Heat Exchanger Design.

Assumptions:
1.
Shell and tube heat exchanger counter flow is used because it is more
efficient than the parallel flow.
The value of the overall heat transfer coefficient was assumed based
on the fluid assigned in both sides.
2.
3.
The outer, the inner diameter , the length of the tube, and the
number of passes were assumed.

For a good design :
1.
The assumed overall heat coefficient has to be equaled to the
calculated overall heat transfer coefficient.,
The pressure drop in the tube side has to be lower than 1 bar.
The pressure drop in the shell side has to be lower than 1 bar.
2.
3.
Shell & Tube Heat Exchanger Design.
Heat Load
Q  M cold c p Tcold  M hotc p Thot
Log mean Temperature
R
Where;
T1 is temperature of inlet hot stream.
(oC)
T2 is the temperature of outlet hot
stream. (oC)
.t1 is the temperature of inlet cold
stream. (oC)
.t2 is the temperature of outlet cold
stream. (oC).
T1  t 2   T2  t1 
 T1  t 2  
ln 
 T  t  

1 
 2
T1  T2  ; S  t 2  t1 
Tlm 
t 2  t1
Tm  Ft Tlm
T1  t1
Shell & Tube Heat Exchanger
Heat Transfer Area
Number of tubes
AreaOfOneT ube  0.25 *  * d o  L
2
Q
A
UTm
Shell and Bundle diameter
1
 N t  n1
Db  d o   ; K1 , n1  f No.Passes 
 K1 
Ds  Db  Re ading Fig .12.10
totalArea
areaOfOneT ube
# tubes
Tubes / Pass 
AssumedPasses
2
cross  Section  area  0.25d i
# tubes 
Area / pass  tubes / Pass cross  sec ton  area 
FlowRate
velocityut  
 Area / Pass * Density
Where ;
Nt is the number of tubes.
K1, n1 are constants.
Db is the bundle diameter (mm)
Ds is the shell diameter. (mm)
Shell & tube heat exchanger Design
Tube Side Heat Transfer Coefficient
cp
ut d i
Re 
; Pr 

k
Nu  jh Re Pr 0.33   
 w 
 kf
hi  Nu
 di
Shell side heat Transfer Coefficient
pt  1.25d o
As 
0.14
L
; jh  f ( )
di



Where
 is the density of fluid (kg/m3).
k is the thermal conductivity (W/m.C).
c p is specific heat (kJ/kg.k).
Re is the Reynolds number.
Pr is the Prandtl number.
Nu is the Nusselt number.
is the convective heat transfer coefficient
(W/m2.C).
 pt  d o Ds lB
pt
us 
FlowRate
As 
de 
1.1 2
2
pt  0.917 d o
do
Re 
cp
u s d e
; Pr 

k



Nu  jh Re Pr 0.33  

 w 
 kf 

hs  Nu
 de 
0.14
; jh  f Re, buffle _ cut 
Where;
.pt is the tube pitch (mm).
.lB is the baffle spacing (mm).
As is the cross flow area (m2)
us is the velocity (m/s).
de is the equivalent diameter for triangular arrangement
(mm).
jh is the heat transfer factor
hs is the convective heat transfer coefficient (W/m2.C).
Shell & Tube Heat Exchanger Design.
Overall Heat Transfer coefficient
d
d o ln  o 
d i   d o  1 
1
1

 
   
U o ho
2k w
 d i  hi 
Tube side pressure Drop
  L     m
 u 2 
  2.5 t 
Pt  N p 8 j f  
  d i   w 
 2 
Shell Side Pressure Drop
 D  L    0.14  u 2 
Ps  8 j f  s     s 
 d e  lB   w   2 
Thickness
D
rj 
2
Pr j
t
 Cc
SE j  0.6 P
Where; D is the shell diameter in m
Rj is internal radius in (in).
P is the operating pressure in psi
S is the working stress (psi).
E is the joint efficiency
Equipment Name
Heater
Objective
Increase Temperature of liquid effluent of CRV-100
Equipment Number
E-102
Designer
Eng. Salem Alkanaimsh
Type
Shell & tube.
Location
Oxidation of EB section
Utility
Low pressure Steam
Material of Construction
Carbon steel
Insulation
Foam Glass
Cost ($)
17000 $
Operating Condition
Shell Side
Inlet temperature (oC)
158.79
Outlet
temperature
(oC)
158.79
Tube Side
Inlet temperature (oC)
80
Outlet
temperature
(oC)
97
Number of Tube Rows
6
Number of
Tubes
347
Tube bundle Diameter (m)
0.03
Shell Diameter
(m)
3
Q total (Btu/hr)
16958400
LMTD (oC)
69.94
U (Btu/hr. oF . ft2)
101.8965
Heat
Exchanger
Area (m2)
114.8
Equipment Name
Heater
Objective
Increase Temperature of liquid effluent of CRV-100
Equipment Number
E-104
Designer
Eng. Salem Alkanaimsh
Type
Shell & tube.
Location
Oxidation of EB section
Utility
Low pressure Steam
Material of Construction
Carbon steel
Insulation
Foam Glass
Cost ($)
85000
Operating Condition
Shell Side
Inlet temperature (oC)
158.79
Outlet
temperature
(oC)
158.79
Tube Side
Inlet temperature (oC)
94.89
Outlet
temperature
(oC)
141
Number of Tube Rows
6
Number of
Tubes
5730
Tube bundle Diameter (m)
0.03
Shell Diameter
(m)
8.3
Q total (Btu/hr)
43334350
LMTD (oC)
36
U (Btu/hr. oF . ft2)
31.1307
Heat Exchanger
Area (m2)
1758
Equipment Name
Heater
Objective
Increase Temperature of EB fed to T-100
Equipment Number
E-105
Designer
Eng. Salem Alkanaimsh
Type
Shell & tube.
Location
Oxidation of EB section
Utility
Low pressure Steam
Material of Construction
Stainless Steel
Insulation
Foam Glass
Cost ($)
8000
Operating Condition
Shell Side
Inlet temperature (oC)
158.79
Outlet
temperat
ure (oC)
158.79
Tube Side
Inlet temperature (oC)
25.128
Outlet
temperat
ure (oC)
40
Number of Tube Rows
4
Number
of Tubes
3149
Tube bundle Diameter (m)
0.07
Shell
Diamete
r (m)
1.45
Q total (Btu/hr)
7984440.5
LMTD
(oC)
126
U (Btu/hr. oF . ft2)
130.581
Heat
Exchang
er Area
(m2)
24.728
Equipment Name
Cooler
Objective
Decrease Temperature of recycle EB
Equipment Number
E-116
Designer
Eng. Salem Alkanimsh
Type
Shell & Tube
Location
EB oxidation
Utility
Cooling water
Material of Construction
Stainless Steel
Insulation
Foam Glass
Cost ($)
15000
Operating Condition
Shell Side
Inlet temperature (oC)
196.4
Outlet
temperat
ure (oC)
186.78
Tube Side
Inlet temperature (oC)
25
Outlet
temperat
ure (oC)
30
Number of Tube Rows
8
Number
of Tubes
3354
Tube bundle Diameter (m)
0.07
Shell
Diamete
r (m)
2.5
Q total (Btu/hr)
5015866.5
LMTD
(oC)
162.44
17.73
Heat
Exchang
er Area
(m2)
90.35
U
(Btu/hr. oF
.
ft2)
Distillation column


1.
A separation unit based on the difference between a liquid
mixture and the vapor formed from it.
It can be subdivided according to:
How complex the unit is:

Simple Distillation.
Flash distillation.
Fractionation.
2.
The internal Design of the column:

Tray Column.
Packing Column.



Distillation Column Design.

Assumptions:

Good Design:
1.
Column Efficiency.
Tray spacing.
Flooding Percentage.
Down Comer Area.
Hole area( 0.1 of Active area).
Weir height ( 40~100)mm.
Hole diameter (10 mm).
Plate Thickness (10~30 mm).
Turn down Percentage (70%)
1.
No weeping.
Down comer back up is less
than half ( plate thickness+
weir height).
No entrainment.
Calculated percentage
flooding equal to the assumed
one.
Residence time exceeds 3 secs.
2.
3.
4.
5.
6.
7.
8.
9.
2.
3.
4.
5.
Distillation Column Design.
Actual Number of trays
AssumeEo 
Re ad N stages/ hysys 
N Re al 
N stages/ hysys  1
Eo
Where; FLV is the vapor-liquid flow
factor.
 is the density in (kg/m3).
 is the surface tension in
(mN/m).
uf is the velocity of vapor in
(m/s).
D is the column diameter (m).
Column Diameter
L
Re ad   ; i  Top, bottom
 V i
 L    v 
FLVi    
 V i   L i
Find K1i ; K1  f Plate  Spacing , FLV 
 
 
Correction  K1i  K1i  i 
 20 
  L  v 

u f MAXi  K1 i 


v

i
u f  Flooding % u f MAXi
0.2
i
Volumetric _ Flow _ Rate i 
Areai 
moleFlow  Mwt 
Volumetric _ Flow _ Rate i
u f Downcomer % 
i
 Area4  

Di  



i
Dc  TakeMAX D
 v i
i
i
Distillation Column Design
Liquid Flow Pattern
VolumerticFlowMAX 
Moleflow Mwt 
liquid
Provisional Plate design
Ac  0.25 Dc 
2
Ad  DownComerArea  Ac DowmComer% 
An  NetArea  Ac  Ad
Aa  ActiveArea  Ac  2 Ad
Ah  holeArea  Aa hole % 
Re ad Fig .11.31 
Ad
l 
 Re ad  w   Find lw 
Ac
 Dc 
Distillation Column Design
Checking Weeping
WeirHeight : hw 


ASSUME   Dh : HoleDiamte r 
 PlateThichness 


LiquidRate MAX  Mwt MoleFlow 
LiquidRate MIN  Turndown% LiquidRate MAX
 LiquidRate MAX 
how MAX  750 

 Llw


 LiquidRate MIN 
howMIN  750 

 L lw


FINDhowMIN  hw 
Fig .11.30  Re ad K 2 
uh 
K 2  0.925.4  Dh 
uvapor 
Down Comer Back up
hap  hw  10
Aap  hap lw 
 L

hdc  166 wd ; Am  MIN Ad ; Aap 
  L  Am 
hb  ht  hdc  hw  howMAX 
Find :
PlateSpacing  hw
2
Residence time
tr 
v
TurnDown % VolumetricFlowVAPOR 
Ah
Ad hbc  L
Lwd
Distillation column design
Estimating the Thickness
Entrainment
uv 
rj 
VolumetricflowRate
An
Flooding % 
t
uv
D
2
Pr j
SE j  0.6 P
 Cc
u fMAX
Find  f F LV Fig .11.29
Cost
H  Tray _ Spacing # trays   2
Vin  D 2 H
Number of holes
AreaOfOneHole  0.25Dh
Ah
# holes 
AreaOfOneHole
2
M in  Vin 
A  D  2 * t 
Vout  A2 H
M out  Vout 
weight  M out  M in
Equipment Name
Distillation Column
Objective
Separates the Final product (PO)
Equipment Number
T-104
Designer
Eng. Salem Alkanimsh
Type
Sieve Tray distillation column
Location
Epoxidation of Propylene section
Material of Construction
Carbon Steel
Insulation
Cost ($)
216,000
Column Flow Rates
Feed (kgmole/hr)
852.6
Recycle
(kgmole/hr)
4372
Distillate (kgmole/hr)
411.1
Bottoms
(kgmole/hr)
441.5
Heavy
Ethyl bezene
Key Components
Light
PO
Dimensions
Diameter (m)
4.37
Height (m)
29
Number of Trays
30
Reflux Ratio
10
Tray Spacing (m)
0.9
Type of tray
Sieve
Number of Holes
91248
Number of
Caps/Holes
Cost
Vessel
180000 $
Trays
36000 $
Condenser Unit
2500 $
Reboiler
10000
Equipment Name
Distillation column
Objective
Separates Styrene from H2O.
Equipment Number
2nd dis.
Designer
Eng. Salem Alkanaimsh
Type
Tray Distillation column
Location
Styrene Production section
Material of Construction
Stainless Steel
Insulation
Foam Glass
Cost ($)
186500
Column Flow Rates
Feed (kgmole/hr)
566.9
Recycle
(kgmole/hr)
399.2
Distillate (kgmole/hr)
11.74
Bottoms
(kgmole/hr)
555.2
Heavy
Styrene
Key Components
Light
Water
Dimensions
Diameter (m)
2.183
Height (m)
12
Number of Trays
11
Reflux Ratio
34
Tray Spacing
0.9
Type of tray
Sieve
Number of Holes
142988
Number of
Caps/Holes
Cost
Vessel
170000 $
Trays
16500 $
Condenser Unit
2300 $
Reboiler
6500 $
Pump Design




Definition.
Suction Calculations.
Discharge Calculations.
NPSH.
Pump Design.
Actual Head of pump
ha 
p2  p1

Water horse Power
Pf 
Efficiency
WHP

BHP
Qha
550
Equipment Name
Objective
Pump
Increase pressure of EB Feed to CRV-100 & T-100
Equipment Number
P-100
Designer
Eng. Salem Alkanaimsh
Type
Centrifugal Pump
Location
EB oxidation section
Material of Construction
Stainless Steel
Insulation
Cost
20000 $
Operating Condition
Inlet Temperature
(oC)
Inlet Pressure (psia)
Efficiency (%)
25
14.7
75
Outlet
Temperature
(oC)
25.09
Outlet Pressure
(psia)
50
Power (Hp)
343
Equipment Name
Objective
Pump
Increase pressure of EB recycled in 1st section
Equipment Number
P-101
Designer
Eng. Salem Alkanaimsh
Type
Centrifugal Pump
Location
EB oxidation section
Material of Construction
Carbon Steel
Insulation
Cost
20,000 $
Operating Condition
Inlet Temperature (oC)
50.11
Outlet Temperature
(oC)
50.15
Inlet Pressure (psia)
1.094
Outlet Pressure (psia)
14.7
Power (Hp)
123
Efficiency (%)
27
Compressor Design


Definition.
Types:
3.
Centrifugal.
Axial.
Reciprocating.

Compression:
1.
Adiabatic.
Isothermal.
Intercooler stage
Pressure Ratio (PR).
1.
2.
2.


Reduce temperature and work
required.
Compressors Design.
Work
p2
p1
T2

T1
k
k 1
k 1


k


k
p
hp  3.03e  5
p1q1  2 
 1
 p1 

k 1


Efficiency =0.8
Isentropic
Compression
Equipment Name
Compressor
Objective
Increase Pressure of air fed to CRV-100
Equipment Number
K-100
Designer
Eng. Salem Alkanimsh
Type
reciprocating Compressor
Location
Oxidation of EB.
Material of Construction
Stainless Steel
Insulation
Cost
100000$
Operating Condition
Inlet Temperature (oC)
Inlet Pressure (psia)
Efficiency (%)
25
14.7
80
Outlet Temperature
(oC)
50
Outlet Pressure
(psia)
188.2
Power (Hp)
3980
Equipment Name
Compressor
Objective
Increase Pressure of outlet of V-104
Equipment Number
K-101
Designer
Eng. Salem Alkanimsh
Type
recirocating Compressor
Location
Oxidation of EB.
Material of Construction
Carbon Steel
Insulation
Cost
202270$
Operating Condition
Inlet Temperature (oC)
Inlet Pressure (psia)
Efficiency (%)
97
1.094
80
Outlet Temperature (oC)
97
Outlet Pressure (psia)
3.094
Power (Hp)
5150