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MAN B&W
Low�duty Compressor
The Low�duty Compressor cons<strong>is</strong>ts of a single
stage compressor with a heavy�duty wheel in
forged aluminium alloy with adjustable inlet guide
vanes, mounted to a heavy�duty speed�increasing
gearbox.
Together with the complete lube oil and seal gas
system the compressor <strong>is</strong> installed on a rigid single
skid for shipboard application, with bulkhead
and bulkhead seal mounted to the gearbox.
An intrinsically safe local control panel with gauge
board <strong>is</strong> installed on the skid, and a remote control
cabinet <strong>is</strong> supplied loose for installation in the
safe area.
To cover the wide temperature range of natural
boil�off gas (�140 °C) and forced gas (�40 °C), the
low�duty compressor <strong>is</strong> normally driven by a variable
speed motor.
Forcing Vapor<strong>is</strong>er
The Forcing Vapor<strong>is</strong>er <strong>is</strong> typically installed upstream
of the L/D Compressors with a M<strong>is</strong>t Separator
at the mixing point with the natural boil�off.
To avoid thermal stress, the proven Shell and
U�tube design <strong>is</strong> applied, directly heated by
saturated steam. The equipment cons<strong>is</strong>ts of a
single�pass shell with stationary head, fully welded
to the U�tube bundle, and <strong>is</strong> entirely fabricated
from stainless steel.
For a reliable temperature control, a Spray Pipe
with integrated Spray Nozzle supplements the vapor<strong>is</strong>er
for efficient mixing of bypassed LNG with
the overheated gas.
MAN Diesel
M<strong>is</strong>t Separator
7.09
Page 7 of 7
If forced gas <strong>is</strong> added to the natural boil�off gas
from the tank, two gases with different gas compositions,
and temperatures are mixed. In a large
mixing range, m<strong>is</strong>t <strong>is</strong> created at the mixing point,
from two essentially dry gases.
The vertical separator vessel, with two inlet nozzles
(from the gas header and Forcing Vapor<strong>is</strong>er)
and one outlet nozzle (to the L/D Compressors),
eliminates more than 99.5% of any m<strong>is</strong>t. A drain
connection and a level switch are included.
The M<strong>is</strong>t Separator <strong>is</strong> entirely fabricated from
stainless steel.
Boil�off Heaters
One small Low�duty or Boil�off Heater <strong>is</strong> installed.
To avoid thermal stress, the proven Shell and
U�tube design <strong>is</strong> applied, directly heated by
saturated steam. The equipment cons<strong>is</strong>ts of a
single�pass shell with stationary head, fully welded
to the U�tube bundle, and <strong>is</strong> entirely fabricated
from stainless steel.
Alternative suppliers
A number of companies can supply compressors
that can fulfil the requirement for application in
connection with an ME�GI engine on an LNG carrier.
We have been in contact with a few, viz.:
Buckhardt � Switzerland
Tomasson � Japan (Licensee)
(used in Japan 12K80MC�GI�S)
GE�Flotech � USA – Sweden
(Nuovo Pignone � Italia (used in MBD four�stroke
power station))
Air Liquide � France
MAN B&W ME�GI engines ME�GI engines 198 48 85�8.4