LEWA Launches New Triplex Drive Unit
More flexibility, less damage to the environment, and improved reaction to price fluctuations: In the future, Qatar’s tanker fleet will rely on dual-fuel engines which either run on heavy oil or liquefied natural gas. To do this, the boil-off gases are reliquefied under high pressure and injected into the ship’s engine.
Since ships are always operating and only brought into dry dock for maintenance once in five years, the high-performance pumps used for this purpose must be extremely robust and temperature-resistant. One of the favorites for the supply of these high-performance pumps is Cryostar SAS, a specialist in cryogenic gases.
As a partner of this French manufacturer, LEWA was entrusted with the development of a new drive unit that meets the strict requirements for this application: With a rod force of 125 kN, the G3M drive unit transforms the rotary movement into an oscillating movement, achieving a maximum power of 160 kW.
Heavy oil is easily obtained, difficult to burn, and can be fed into the engine at low pressure. When the large transport ships of the Q-flex and Q-max LNG fleet were built nine years ago, the decision was therefore made to use slow-running diesel engines, since these are also thermally more efficient than steam turbines and burn less fuel. But it is foreseeable that tankers like those in Qatar will have to convert to other fuels in the future for environmental reasons – at least near the coast. Transport ships with dual-fuel engines like the ones the Emirate wants to use, however, are new territory for everyone involved. Many ship-owners found the technical risk too high, since LNG can be transported safely in the liquid state only at very low temperatures. However, the option of using on-board natural gas as a fuel is also becoming more attractive because engine efficiency is improved in comparison with heavy oil.
Source: LEWA, January 15, 2014