AMATERASU
Job No.
01
LATOM
PROJECT
Line Sizing for Single Phase Gas
Prepared by:
Aldi Togu Susanto
REV
DATE
DESCRIPTION
CHK'D APP'D
Date :05/18/2025
Prepared by : ATS
01 Tag : Checked by : Quixn
Client :
Rev no :
Title : "Line Sizing for Single Phase Gas"
Case Study
Perform line sizing based on the given criteria for a gas flow with the
following gas properties :
Operating Temperature, (T)
Operating Pressure, (P)
std. Gas Flow rate, (Qg)
Molecular Weight, (MW)
73.89
2.9
1.2
23.32
o
C
psig
MMSCFD
165.00
17.6
F
psia
Density, (p)
0.9828 kg/m
0.061
Viscosity, (µ)
0.0135 cP
Compressibility Factor, (Z)
0.9976
Cp/Cv, (k)
1.242
Length, (L)
100
ft
*Note: Fluid Properties obtained from Aspen Hysys
lb/ft
3
624.67
R
3
Design Criteria
1. Maximum Velocity
=
60 ft/s
API RP 14E
2. Maximum Mach Number
=
0.5
API STD 521
3. Pressure Drop
= 0.25 1.5 psi/100 ft
GPSA Section 17
*Note: These criteria are based on API Standards and GPSA Technical Data Books.
These criteria can be adapted to other criteria.
Calculation
1. Determine the Pipe Roughness Value
Pipe Material
= Carbon Steel
Pipe Condition
=
New
Pipe Roughness Value
=
0.0018
in
0.0457
2. Take any Nominal Pipe Size (NPS) as trial and error
Nominal Pipe Size
=
4"
Schedule
=
40
Inside Diameter
= 102.26 mm
4.03
mm
in
3. Calculate the Design Volumetric Flow Rate (Q design)
Qdesign
Margin
Then,
Qdesign
Where:
Qdesign
Margin
Qg
= (
=
1 + Margin ) x Qg
10%
=
1.32
MMSCFD
= Design Volumetric Flow Rate (MMSCFD)
= Additional Design Margin
= Gas Flow Rate (MMSCFD)
0.34
ft
Date :05/18/2025
Prepared by : ATS
01 Tag : Checked by : Quixn
Client :
Rev no :
Title : "Line Sizing For Single Phase Gas"
4. Calculate Specific Gravity (SG)
MWgas
=
23.32
MWair
=
28.97
SG
=
=
Where:
SG
MWgas
MWair
MWgas
MWair
0.8050
= Gas Specific Gravity (dimensionless)
= Molecular Weight of the Gas
= Molecular Weight of the Air
5. Calculate the Mass Flow Rate (W)
W
W
Q x 144 x P
R x T x Z
= 3740.595 lb/hr
=
Where:
R
= Universal Gas Constant
T
P
Z
W
=
=
=
=
o
=
=
=
=
o
Temp at Standard Conditions ( R or [60 F + 459,67])
Pressure at Standard Conditions
(
14.7
Psia )
Compressibility Factor (dimensionless)
Mass Flow Rate (lb/hr)
6. Calculate the Sound of Speed (c)
k x T
c
= 223 (
)0,5
MW
= 1286.26 ft/s
Where:
c
k
T
MW
o
1545.348 ft.lbf/(lbmol. R)
Speed of Sound (ft/s)
Cp/Cv (dimensionless)
Operating Temperature (R)
Gas Molecular Weight
Date :05/18/2025
Prepared by : ATS
01 Tag : Checked by : Quixn
Client :
Rev no :
Title : "Line Sizing For Single Phase Gas"
7. Calculate the Fluid Velocity (v)
60 x Z x Qdesign x T
v
=
2
ID x P
Where:
v
Z
Qdesign
T
ID
P
=
173.012 ft/s
=
=
=
=
=
=
Gas Velocity (ft/s)
Compressibility Factor (dimensionless)
Design Volumetric Flow Rate (MMSCFD)
Operating Temperature (R)
Inside Diameter (Inch)
Operating Pressure (psia)
8. Calculate Mach Number (Ma)
v
Ma
=
c
= 0.1345
Where:
Ma
v
c
= Mach Number (dimensionless)
= Gas Velocity (ft/s)
= Speed of Sound (ft/s)
9. Calculate Reynold Number (Re)
Re
=
=
Where:
Re
p
ID
v
µ
p x ID x v
µ
392104.72
= Reynold Number (dimensionless)
3
= Mass Density (lb/ft )
= Pipe Inside Diameter (ft)
= Gas Velocity (ft/s)
= Viscosity (lb/ft.s), or cP divided by 1,488
Date :05/18/2025
Prepared by : ATS
01 Tag : Checked by : Quixn
Client :
Rev no :
Title : "Line Sizing for Single Phase Gas"
10. Calculate Friction Factor (f)
If the flow in the pipe is laminar (Re<2000), then use following equation:
64
f
=
Re
where:
f
Re
= friction factor (dimensionless)
= Reynold Number (dimensionless)
If the flow in the pipe is turbulent (Re>4000), then use following equation:
0.25
f
=
ɛ / ID
5.74
[ log10 (
+
) ]2
0,9
3.7
Re
=
0.01769
where:
f
= friction factor (dimensionless)
Re
= Reynold Number (dimensionless)
ɛ
= Pipe Roughness Value (in)
ID
= Pipe Inside Diameter (in)
11. Calculate the Pressure Drop (ΔP)
ΔP
where:
ΔP
f
W
ID
p
=
x f x W
0.000336
2
5
=
=
(ID) x p
1.28131 psi/100 ft
128.131 psi
=
=
=
=
Pressure Drop (psi/100 ft)
Friction Factor (dimensionless)
Mass Flow Rate (lb/hr)
Pipe Inside Diameter (in)
3
= Mass Density (lb/ft )
Date :05/18/2025
Prepared by : ATS
01 Tag : Checked by : Quixn
Client :
Rev no :
Title : "Line Sizing For Single Phase Gas"
Nominal Pipe Size
Schedule No
Inside Diameter
Fluid Velocity
Mach Number
Pressure Drop
Line Sizing Result
Option 1
[in]
4"
40
[in]
4.03
[ft/s]
173.012
[Ma]
0.1345
[psi/100ft]
1.28131
[psi]
128.131
Option 2
6"
40
6.07
76.207
0.0592
0.16115
16.115
Option 3
8"
40
7.98
44.016
0.0342
0.04099
4.099
CRITERIA
Maximum Velocity
Maximum Mach Number
Maximum Pressure Drop
[ft/s]
[ft/s]
[psi/100 ft]
60
0.5
0.25
CONCLUSION
Velocity Check
Mach Number Check
Pressure Drop Check
Remark
OV!
OK
OPD!
NOT OK
OV!
OK
OK
NOT OK
OK
OK
OK
OK