MAN B&W S65ME-C8.2-GI-TII, Руководство по проекту, Страница: 193 / 395

MAN B&W
Page 7 of 9
MAN Diesel
7.07
MAN B&W ME-GI TII engines 198 86 37-7.2
Generating of fuel gas pressure
The pressure can be generated by the FGS in dif-
ferent ways depending on the storage condition of
the gas. Some of the possibilities are:
• high-pressure gas compressor, including coolers,
pulsation dampers, condensate separator etc.
• high-pressure cryogenic pump to deliver high
pressure LNG to an evaporator
• a combination of the above solutions.
Examples of fuel gas supply systems is described
in Section 7.08.
Control of the fuel gas supply system
A description of the ME-GI Engine Control System
(ME-GI-ECS) is provided in Section 16.02.
The fuel gas pressure is to be controlled on the
basis of the gas supply pressure set point, and
the actual fuel gas load specified by the GI-ECS.
The control signal interface is shown in Fig. 16.02.03
‘GI Extension Interface to External Systems’ and
the diagram of the gas valve train is shown in Fig.
7.07.03.
0%
0
50
100
150
200
250
300
350
10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 110% 120%
Engine load (%SMCR)
G
as
s
u
p
p
ly
p
re
ss
u
re
s
et p
o
in
t (
b
ar
)
Gas supply pressure set point range
Fig. 7.07.04: The expected range of the gas pressure requirement for the FGS system
505 92 45-4.6.0a
The gas supply pressure set point is expected to
change from 200 bar to 300 bar dependent on
engine load. The allowable deviation from the gas
supply pressure set point is:
Deviation from set point (dynamic) ±5%
This requirement is to be fulfilled at a gas flow rate
disturbance frequency of 0.1 Hz, and a gas flow
rate variation (kg/s) relative to the gas flow rate at
MCR of ±15%. This requirement has to be fulfilled
also for the lowest calorific values of the gas.
Deviation from set point (static) ±1%
For using BOG from cargo tanks like LNG tankers,
the FGS must be able to read the calorific value of
the supplied gas to the main engine.
FGS pressure requirement guideline
The expected range of the gas pressure require-
ment for the FGS system is shown in Fig. 7.07.04.
The gas supply pressure set point will be within
the dotted area.