Arctic technology: Winterisation of FPSO 38 Cruise ... - Ship & Offshore

SHIPBUILDING & EQUIPMENT | GREEN SHIP TECHNOLOGY
The E-Ship 1 was tailor-made for the transport of wind-turbine components
Photo: Chrisostomos Fountis
two tween decks are vertically adjustable
to ensure maximum fl exibility for the
cargo.
Wheeled cargo can be loaded or unloaded
via a ramp at the ship’s stern. For conventional
cargo, there are two onboard portside
cranes, each with a lifting capacity of
90t. The E-Ship 1 is also capable of carrying
up to 853 TEU and has more than 92
electrical outlets for refrigerated containers.
All of the deck machinery, consisting
of anchor and mooring winches, was
supplied by the company Steen, based in
Elmshorn, Germany, in close consultation
with the shipyard and Enercon.
The moulded depth of the dark-green
hull was affected by inclusion of a special
cassette system meant to ease the loading
and stowing of wind-turbine components.
They are carried largely below
deck, which reduces the risk of damage
during transport.
Hybrid propulsion system
The E-Ship 1 is equipped with seven Mitsubishi/Leroy
Somer diesel gensets of
two different types, generating about
10,000kW. They feed the two Enerconmade
electric engines, each with an output
of 3,500kW, which power the drive shaft
and four-blade controllable-pitch propeller.
In addition, the vessel has two Mitsubishi
S6R-MPTA auxiliary diesel engines for
harbour and emergency operations.
Rotor sail Standard diesel-electric propulsion
is supplemented by four cylindrical
18 Ship & Offshore | 2011 | N o 1
rotors that act as sails, producing thrust
from the wind blowing past them. “Rotor
sails” were invented by the German engineer
Anton Flettner, who put marine rotor
propulsion into practice for the fi rst time
on the freighters Buckau and Barbara in the
1920s.
The rotors on the E-Ship 1 are 27m high
and 4m in diameter. They use the Magnus
effect, described in the mid-19th century
by the German physicist Heinrich G.
Magnus. In this effect, a body spinning in
an air stream creates a pressure differential
on either side of the body, producing
a force.
When wind blows across the rotating cylinders,
they speed up on the side where
rotational and wind direction meet. On
the opposite side, however, airfl ow is
slower. The resulting higher pressure of
air on one side and lower pressure on the
other produces a force perpendicular to
the airfl ow that is used to propel the ship.
Optimal thrust is achieved when wind
strikes the rotors at an angle of 100 to 130
degrees relative to the ship’s course. A tailwind
augments thrust. But to travel best
in a headwind, the ship has to tack like a
conventional sailing vessel.
For greater fl exibility in reducing engine
output when thrust is available from the
fully automatic rotors, designers of the
E-Ship 1 decided on several small gensets
instead of a large engine. The ship’s top
speed under engine propulsion only, or
under rotor propulsion when wind conditions
are ideal, is 18.5 knots.
Waste-heat recovery The Danish company
Aalborg Industries supplied the E-Ship 1
with a Mission WHR-GT forced-circulation
waste-heat recovery boiler whose water
tube has an extended heating surface.
The boiler uses the mixed exhaust-gas heat
from the seven propulsion and onboard
power supply generators to make superheated
steam that runs a turbogenerator
for energy production. Using waste heat
to operate a steam turbine is a further example
of the vessel’s highly sophisticated
technology. The turbine also provides heat
required for the absorption refrigeration
system, which supports the conventional
climate control system.
Extensive control and monitoring units for
the cooling water as well as the exhaust gas
are indispensable for the installation’s safe
and reliable operation.
Main characteristics of Mission WHR-GT
� Number of engines: 5
� Engine load: 85% MCR
� Amount of exhaust: 39 t/h at 520 °C
� Exhaust temperature: 103 °C
� Amount of superheated steam: 4.72 t/h
at 354°C at 15 bar (g)
� Heat extraction for absorption refrigeration
system: 200kW
Electrical engineering/automation
The vessel’s extensive electrical equipment
was supplied by the company Rolf
Janssen, which is based, like Enercon, in
the northern German town of Aurich. It
includes fi ve propulsion power plants with
an output of 1,750 kVA each, two onboard
power plants with an output of 1,300 kVA
as well as a harbour and emergency/harbour
power plant, each with an output of
580 kVA.
Rolf Janssen also supplied the distribution
panels, harbour and emergency switchboard,
consoles and alarm and monitoring
systems.
Advanced automation technology ensures
a trouble-free shift from rotor-sail to conventional
propulsion as well as maximum
navigational availability and reliability
with a small crew. The continuous system,
with built-in redundancies, was supplied
by Nuremberg-based Siemens Industry Automation
and programmed by Enercon.
Transport of wind turbines
E-Ship 1 has been in regular service for
Enercon since August 2010, visiting ports
in Ireland, France, Portugal, Turkey and
Greece to deliver turbines for onshore
wind parks. The voyages have also been
undertaken to test the vessel’s equipment
and seakeeping performance under normal
cargo conditions. Data was gathered
to evaluate the effi ciency of its systems and
components.