MAN B&W S65ME-C8.2-GI-TII, Руководство по проекту, Страница: 312 / 395

MAN B&W 16.02
Page 3 of 6
MAN Diesel MAN B&W ME-GI engines 198 89 31-2.1
Gas safety control
The task of the safety system is to monitor:
• manual and external automatic gas shut down
• engine shut down signal from the engine safety
system
• double-pipe ventilation and leakage
• sealing oil pressure
• gas pressure
• combustion pressure within normal values
• gas injection valve and window valve leakage.
If one of the above mentioned failures is detected,
the gas safety control releases the fuel gas shut
down sequence:
The window valve and the main gas valve, safety
will be closed. The ELGI valves will be disabled.
The fuel gas will be blown out by opening the gas
bleed valve, the blow-off valves and purge valves,
and finally the gas pipe system will be purged with
inert gas. See Fig. 7.00.01.
Safety principles of the Gas Dual Fuel Control
System
Gas mode running is not essential for the ma-
noeuvrability of the ship as the engine will contin-
ue to run on fuel oil if an unintended fuel gas stop
occurs. The two fundamental safety principles of
the fuel gas equipment are, in order of priority:
• Safety to personnel must be at least on the
same level as for a conventional diesel engine
• A fault in the dual fuel equipment must cause stop
of gas operation and change over to fuel oil mode
which to some extent complement each other.
The Dual Fuel Control System is designed to ‘fail
to safe condition’. All failures detected during fuel
gas running and failures of the control system it-
self will result in a fuel gas Stop / Shut down and
change over to fuel oil operation.
Subsequently, the control system initiates blow
out and purging of high pressure fuel gas pipes
which releases all gas from the entire gas supply
system of the engine room.
If the failure relates to the purging system, it may
be necessary to carry out purging manually be-
fore an engine repair is carried out.
The Dual Fuel Control system itself is in general
a single system without redundancy or manual
backup control.
Control Unit Hardware
For the GI extension, two different types of hard-
ware are used: the MPC (Multi Purpose Controller)
units and the GCSU (Gas Cylinder Safety Unit),
both developed by MAN Diesel & Turbo.
The MPC units are used for the following units:
GPCU (Gas Plant Control Unit), GACU (Gas Auxil-
iary Control Unit), GPSU (Gas Plant Safety Unit) as
well as the ECU and CCU. A functional description
of the units is given in the following, see also the
diagram Fig. 16.02.01.
Main Operating Panel
The Main Operating Panel (MOP) is common to
both the ME-ECS and the GI extension. From here
all the manual operations can be initiated.
The MOP functions include the facilities to manu-
ally start up or to stop fuel gas operation.
Additionally, for example the change between the
different running modes can be done and the op-
erator has the possibility to manually initiate the
purging of the gas piping with inert gas.