Marine Installation Manual
2021-08
4-50
4 Ancillary Systems
4.4 Fuel gas system
X72DF
Advantage of variable
fuel gas supply pressure
WinGD recommends energy-saving variable fuel gas supply pressure to the
iGPR or the GVU inlet. If the fuel gas is supplied by means of a compressor, the
savings can be significant, while for supply by means of an LNG pump, the sav
-
ings are minor. For LNG pump operation, the pressure adaptation has the addi
-
tional advantage of creating less heat input into the LNG tank by reducing the
pump’s mechanical work. Finally, variable fuel gas supply pressure supports
stable engine operation at minimum power. However, constant fuel gas supply
pressure is possible but not recommended because of the reasons mentioned be
-
fore.
Pressure control of the
FGSS with iGPR
The Engine Control System (ECS) determines the set-point of the fuel gas supply
pressure and transmits the controlling signals to the Propulsion Control System
(PCS) and the iGPR. The PCS transmits the set-point to the FGSS (see
for basic information about the control system interfaces).
The data transmitted to the FGSS includes an additional pressure offset to ac
-
commodate for pressure losses and dynamic load changes in the system. The
pressure offset is a project-specific input that is calculated and set in the PCS.
Figure 4
-
29 Fuel gas supply pressure control at the engine inlet (engines with iGPR)
Pressure control of the
FGSS with GVU
The ECS determines the set-point of the fuel gas supply pressure at the GVU inlet
and transmits the controlling signals to the PCS, which then requests pressure in
-
crease or decrease from the GVU. In addition, the PCS transmits the set-point to
the FGSS (see
for basic information about the control system
interfaces).
The data transmitted to the FGSS includes an additional pressure offset to ac
-
commodate for pressure losses and dynamic load changes in the system. The
pressure offset is a project-specific input that is calculated and set in the PCS.
SM-0210
P
set-point
+ P
offset
P
set-point
P
set-point
P
set-point
- Set-point of the fuel gas supply pressure at the engine inlet
P
offset
- Fuel gas supply pressure offset to compensate for:
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Control System
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Engine
Control System
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