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5.16
Gas pressure
The Tab. K shows minimum pressure losses along the gas sup-
ply line depending on the maximum burner output operation.
1 p
kW
(mbar)
930
4.3
1000
5.1
1100
6.2
1200
7.4
1300
8.6
1400
10.0
1500
11.5
1600
13.1
1700
14.7
1860
17.7
Column 1 (Tab. K)
Pressure loss at combustion head.
Gas pressure measured at test point 1)(Fig. 25), with:
–
combustion chamber at 0 mbar
–
combustion head adjusted as indicated in diagram (Fig. 29 at
page 26).
Column 2 (Tab. K)
Pressure loss at gas butterfly valve 2)(Fig. 25) with maximum
opening: 90°.
Column 3 (Tab. K)
Pressure loss of gas train 3)(Fig. 25) with gas G20 includes:
–
adjustment valve VR
–
safety valve VS (both fully open)
–
pressure governor R
–
filter F (see components in Tab. I at page 22)
The values shown in the Tab. K refer to:
natural gas G 20 PCI 10 kWh/Nm
With:
natural gas G 25 PCI 8.6 kWh/Nm
ulated values:
–
column 1: by 1.3;
–
column 2-3: by 1.49
Calculate the approximate maximum output of the burner thus:
–
subtract the combustion chamber pressure from the gas
pressure measured at test point 1)(Fig. 25).
–
Find the nearest pressure value to your result in column 1 of
the Tab. K.
–
Read off the corresponding output on the left.
Example
•
Maximum output operation
•
Natural gas G20 PCI 10 kWh/Nm
•
Gas pressure at test point 1)(Fig. 25)
•
Pressure in combustion chamber
A maximum output of 1600 kW shown in Tab. K corresponds to
13 mbar pressure, column 1, gas G20.
This value serves as a rough guide, the effective delivery must be
measured at the gas meter.
2 p
3970146
(mbar)
3970160
0.9
17.0
1.0
19.5
1.3
22.5
1.6
27.0
1.9
32.0
2.2
35.0
2.6
40.0
2.9
45.0
3.3
52.0
3.8
62.0
3
3
(8.6 Mcal/Nm
)
3
3
(7.4 Mcal/Nm
) multiply tab-
3
=
16 mbar
=
3 mbar
16 - 3
=
13 mbar
Installation
3 p (mbar)
3970181
3970147
3970182
3970161
15.0
6.3
17.0
7.4
20.0
8.5
23.5
10.0
27.5
12.0
29.0
15.0
32.0
16.0
35.0
17.0
38.5
19.0
45.0
23.0
To calculate the required gas pressure at test point 1)(Fig. 25),
set the maximim output required from the burner operation:
–
find the nearest output value in the Tab. K.
–
Read off the pressure at test point 1)(Fig. 25) on the right in
column 1.
–
Add this value to the estimated pressure in the combustion
chamber.
Example
•
Required burner maximum output operation: 1600 kW
•
Natural gas G20 PCI 10 kWh/Nm
•
Gas pressure at burner output of 1600 kW,
column 1
•
Pressure in combustion chamber
pressure required at test point 1)(Fig. 25).
23
GB
3970148
3970149
3970162
3970163
-
-
-
-
4.5
-
5.4
-
6.0
-
7.0
-
8.0
-
9.0
4.5
10.0
4.7
12.0
5.5
3
=
13 mbar
=
3 mbar
13 + 3
=
16 mbar
D3001
Fig. 25
20035573
Tab. K
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