Man B&W S50ME-B9.3-TII, Project Manual

Page: 159 / 337

MAN B&W 7.01
Page 3 of 3
MAN Diesel
MAN B&W S50MEC, G50ME-B, S50ME-B, S46ME-B,
S40ME-B, G40ME-B, S35ME-B, S30ME-B
198 76 610.4
Engine
Flow rate,
litres/cyl. h.
HFO 12 cSt
S50ME-C, G/S50ME-B 0.25
S46/40/35/30ME-B 0.25
G40ME-B 0.25
Table 7.01.02: Approximate flow in HCU leakage drain.
Drain of clean fuel oil from HCU, pumps, pipes
The HCU Fuel Oil Pressure Booster has a leakage
drain of clean fuel oil from the umbrella sealing
through ‘AF’ to the fuel oil drain tank.
The flow rate in litres is approximately as listed in
Table 7.01.02.
This drained clean oil will, of course, influence the
measured SFOC, but the oil is not wasted, and the
quantity is well within the measuring accuracy of
the flowmeters normally used.
The main purpose of the drain ‘AF’ is to collect
pure fuel oil from the fuel pumps as well as the
unintentional leakage from the high pressure
pipes. From the drain tank, the drained fuel oil is
led to a storage tank or to the settling tank.
The ‘AF’ drain is provided with a box for giving
alarm in case of leakage in a high pressure pipe.
The size of the sludge tank is determined on the
basis of the draining intervals, the classification
society rules, and on whether it may be vented
directly to the engine room.
Drain ‘AF’ is shown in Fig. 7.03.01.
Drain of contaminated fuel etc.
Leakage oil, in shape of fuel and lubricating oil
contaminated with water, dirt etc. and collected
by the HCU Base Plate top plate, is drained off
through the bedplate drains ‘AE’.
Drain ‘AE’ is shown in Fig. 8.07.02.
Heating of fuel drain pipes
Owing to the relatively high viscosity of the heavy
fuel oil, it is recommended that the drain pipes
and the fuel oil drain tank are heated to min. 50 °C,
but max. 100 °C.
The drain pipes between engine and tanks can
be heated by the jacket water, as shown in Fig.
7.01.01 ‘Fuel oil system’ as flange ‘BD’.
Fuel oil flow velocity and viscosity
For external pipe connections, we prescribe the
following maximum flow velocities:
Marine diesel oil .......................................... 1.0 m/s
Heavy fuel oil ............................................... 0.6 m/s
The fuel viscosity is influenced by factors such as
emulsification of water into the fuel for reducing
the NO
x
emission. This is further described in Sec-
tion 7.06.
An emulsification arrangement for the main engine
is described in our publication:
Exhaust Gas Emission Control Today and
Tomorrow
Further information about fuel oil specifications is
available in our publication:
Guidelines for Fuels and Lubes Purchasing
The publications are available at www.marine.
man.eu
→
’Two-Stroke’
→
’Technical Papers’.