Pipeline ancillaries Separators and insulation jackets
10
Steam sizing example - kg/h, bar g and m/s The steam sizing example below has been based on imperial O/D tubing delivering 500 kg/h of steam at 6 bar g. 1. Plot point A where the steam pressure and flowrate cross, e.g. 6 bar g @ 500 kg/h: Draw a horizontal line. 2. Select line size . Any separator curve that is bisected by this line at a velocity below 27 m/s will operate at near 100% efficiency. For this example choose a 2" (DN50) separator, point B . 3. Ascertain velocity . Line velocity for any size can be determined by drawing a vertical line upwards from the point of intersection. From point B in this example the line crosses the velocity axis at 15 m/s. Note: a velocity correction factor needs to be applied - Please refer to the correction factor table below. For this example the velocity correction factor is 1.22 for a 2" imperial O/D tube therefore the velocity in this example would be 18.3 m/s. 4. Pressure drop . Where the line extended from point B crosses the line C – C , plot a horizontal line. Now drop a vertical line from point A . The point of intersection, D , is the pressure drop across the separator, i.e. approximately 0.012 bar. 5. Separators should be selected on the basis of the best compromise between line size, velocity and pressure drop for each application. Steam pressure bar g Flow velocity m/s
0
2
4
6
7.6
5
10
15
20
25
30
34
40
2"
B
1½"
A
¾" and 1"
½"
C
D
10.7 58
C
Pressure drop across separator bar (approximate)
Separator size
½"
¾"
1"
1½"
2"
I/D (mm)
15.80
21.00
26.60
40.90
52.50
Schedule 40 pipe
Factor
1.00 9.40 2.83
1.00
1.00
1.00
1.00
Velocity correction factor table
I/D (mm)
15.75
22.10
34.80
47.50
Imperial O/D tubing
Factor
1.45
1.45
1.38
1.22
I/D (mm)
15.00
19.00
25.00
37.00
49.00
Hybrid DIN 11850 pipe
Factor
1.11
1.13
1.13
1.22
1.15
TI-P023-59 CMGT Issue 7
Page 4 of 7
CS10-1 Stainless Steel Clean Steam Separator
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