Trap
pressure
bar g
Boiler house
Heat recovery systems
Sizing a Flash Vessel on up to Three Trap Pressures
Flash pressure bar g
0
0.5
1
1.5
2
2.5
3
4
5
6
7
8
9
10
% flash
40
29.9
28.1
26.8
39
29.6
27.8
26.4
38
29.3
27.5
26.1
37
29.0
27.2
25.8
36
28.7
26.8
25.4
35
28.3
26.5
25.1
34
27.9
26.1
24.7
33
27.6
25.8
24.4
32
27.2
25.4
24.0
31
26.9
25.0
23.6
30
26.5
24.7
23.2
29
26.1
24.3
22.9
28
25.7
23.9
22.4
27
25.3
23.5
22.0
26
24.9
23.1
21.6
25
24.5
22.6
21.2
24
24.1
22.2
20.7
23
23.6
21.7
20.3
22
23.2
21.3
19.8
21
22.7
20.8
19.3
20
22.2
20.3
18.8
19
21.7
19.8
18.3
18
21.2
19.3
17.8
17
20.6
18.7
17.2
16
20.1
18.2
16.7
15
19.5
17.6
16.1
25.6
24.6
25.3
24.3
25.0
23.9
24.6
23.6
24.3
23.3
23.9
22.9
23.5
22.5
23.2
22.2
22.8
21.8
22.4
21.4
22.0
21.0
21.7
20.6
21.3
20.2
20.8
19.8
20.4
19.4
20.0
18.9
19.5
18.5
19.1
18.0
18.6
17.6
18.1
17.1
17.6
16.6
17.1
16.0
16.6
15.5
16.0
14.9
15.4
14.3
14.8
13.7
14.2
13.1
13.5
12.4
12.8
11.7
12.0
10.9
11.3
10.1
10.4
9.3
9.5
8.4
8.5
7.4
7.4
6.3
6.2
5.0
4.8
3.6
3.2
2.0
1.2
-
-
-
0.714 0.603
% Flash
%
%
%
23.7
23.4
23.1
22.7
22.4
22.0
21.6
21.3
20.9
20.5
20.1
19.7
19.3
18.9
18.5
18.0
17.6
17.1
16.6
16.1
15.6
15.1
14.5
14.0
13.4
12.8
12.1
11.4
10.7
10.0
9.2
8.3
7.4
6.4
5.2
4.0
2.6
0.9
-
-
0.522
X
X
X
22.9
21.5
22.6
21.2
22.3
20.9
21.9
20.5
21.6
20.2
21.2
19.8
20.8
19.4
20.5
19.0
20.1
18.7
19.7
18.3
19.3
17.9
18.9
17.5
18.5
17.0
18.1
16.6
17.6
16.2
17.2
15.7
16.7
15.3
16.3
14.8
15.8
14.3
15.3
13.8
14.8
13.3
14.2
12.7
13.7
12.2
13.1
11.6
12.5
11.0
11.9
10.4
11.2
9.7
10.6
9.0
9.8
8.3
9.1
7.5
8.3
6.7
7.4
5.8
6.5
4.9
5.4
3.8
4.3
2.7
3.1
1.4
1.7
-
-
-
-
-
-
-
0.461 0.374
Condensate load
kg/h
kg/h
kg/h
Velocity factor
20.3
19.2
18.2
20.0
18.9
17.9
19.6
18.5
17.5
19.3
18.2
17.2
18.9
17.8
16.8
18.5
17.4
16.4
18.2
17.0
16.0
17.8
16.7
15.7
17.4
16.3
15.3
17.0
15.9
14.9
16.6
15.5
14.4
16.2
15.1
14.0
15.8
14.6
13.6
15.3
14.2
13.2
14.9
13.8
12.7
14.4
13.3
12.2
14.0
12.8
11.8
13.5
12.3
11.3
13.0
11.8
10.8
12.5
11.3
10.3
12.0
10.8
9.7
11.4
10.2
9.2
10.8
9.7
8.6
10.3
9.1
8.0
9.7
8.5
7.4
9.0
7.8
6.7
8.4
7.1
6.0
7.6
6.4
5.3
6.9
5.7
4.6
6.1
4.9
3.8
5.3
4.1
2.9
4.4
3.2
2.0
3.5
2.2
1.1
2.4
1.2
-
1.3
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.315 0.272 0.240
Mass flash
=
kg/h
=
kg/h
=
kg/h
* Velocity
17.3
17.0
16.6
16.2
15.9
15.5
15.1
14.7
14.3
13.9
13.5
13.1
12.6
12.2
11.7
11.3
10.8
10.3
9.8
9.3
8.7
8.2
7.6
7.0
6.4
5.7
5.0
4.3
3.5
2.7
1.9
1.0
-
-
-
-
-
-
-
-
0.215
16.5
15.6
16.1
15.3
15.7
14.9
15.4
14.6
15.0
14.2
14.6
13.8
14.2
13.4
13.8
13.0
13.4
12.6
13.0
12.2
12.6
11.8
12.2
11.3
11.7
10.9
11.3
10.5
10.8
10.0
10.4
9.5
9.9
9.0
9.4
8.5
8.9
8.0
8.4
7.5
7.8
6.9
7.2
6.4
6.7
5.8
6.1
5.2
5.4
4.5
4.8
3.9
4.1
3.2
3.3
2.4
2.6
1.7
1.8
0.9
0.9
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.194 0.177
Total flash steam
kg/h
Choose on < 3 m/s
FV6
FV8
FV12
FV15
FV18
2.8.16
14
13
12
11
10
9
8
7
6
5
4
3
2
1
LPFactor =
Trap pressure
bar g
bar g
bar g
Total
flash steam
18.9
16.9
15.4
18.2
16.3
14.8
17.5
15.6
14.1
16.8
14.8
13.3
16.1
14.1
12.5
15.2
13.2
11.7
14.4
12.3
10.8
13.4
11.4
9.8
12.3
10.3
8.7
11.2
9.1
7.5
9.8
7.7
6.1
8.3
6.2
4.5
6.3
4.2
2.6
3.8
1.7
-
kg/h
X
m
3
/h
÷
1.673
1.149 0.881
Flash pressure
bar g
bar g
bar g
=
LP factor
Total volume
67
138
243
=
385
560
m/s
m/s
m/s
m/s
m/s
* Note: Size on a take-off velocity of 3 m / s or less.
AI-P404-12 AB Issue 3
Sizing A Flash Vessel On Up To Three Trap Pressures
