5.12.4 Gas Pressure - Riello RS 810/E FGR Installation, Use And Maintenance Instructions

5.12.4 Gas pressure

Tab. L indicates the minimum pressure drops along the gas sup-
ply line, depending on the maximum burner output.
The values shown in Tab. L refer to:
– Natural gas G 20 NCV 9.45 kWh/Sm
Column 1
Pressure drop on combustion head.
Gas pressure measured at the test point P1) (Fig. 23), with:
• Combustion chamber at 0 mbar;
• Burner working at maximum output;
• Combustion head adjusted as in page 21.
Column 2
Pressure loss at gas butterfly valve 10)(Fig. 21) with maximum
opening: 90°.
Calculate the approximate maximum output of the burner in this
way:
– subtract the combustion chamber pressure from the gas
pressure measured at test point P1) (Fig. 23).
– Find, in the table Tab. L related to the burner concerned, the
pressure value closest to the result of the subtraction.
– read the corresponding output on the left.
Example for RS 810/E FGR with G20 natural gas:
Maximum output operation
Gas pressure at test point P1)(Fig. 23)
Pressure in combustion chamber
A pressure of 41.7 mbar, column 1, corresponds in the table Tab.
L to an output of 5250 kW.
This value serves as a rough guide; the effective output must be
measured at the gas meter.
To calculate the required gas pressure at test point P1) (Fig. 23),
set the MAX output required from the burner operation:
– find the nearest output value in the table Tab. L for the burner
in question.
– read, on the right (column 1), the pressure at the test point
P1)(Fig. 23).
– Add this value to the estimated pressure in the combustion
chamber.
Example for RS 810/E FGR with G20 natural gas:
Required burner maximum output operation: 5250 kW
Gas pressure at an output of 5250 kW
Pressure in combustion chamber
Pressure required at test point P1)(Fig. 23).
The heat output and gas pressure data in the
head refer to operation with gas butterfly valve
fully open (90°).
WARNING
20163821
Installation
3 3
(8.2 Mcal/Sm )
= 43.7 mbar
= 2 mbar
43.7 - 2 = 41.7 mbar
= 41.7 mbar
= 2 mbar
41.7 + 2 = 43.7 mbar
26
kW
3500
3850
4200
4550
4900
5250
5600
6050
6300
6650
7990
0% Flue gas recirculation
GB
1 p (mbar) 1 p (mbar)
G 20 G 20
18.4 0.4
22.4 0.5
26.7 0.7
31.3 0.8
36.3 0.9
41.7 1.1
47.5 1.2
55.5 1.4
60.1 1.9
67.2 2.1
74.2 2.2
Tab. L