Taking on the turbines5 June 2002
What is claimed to the world's largest gas engine has been launched by Wärtsilä. The 50DF, producing 950 kW per cylinder, is a four-stroke 500 rpm (50Hz)/514 rpm (60Hz) 500 mm bore dual-fuel engine that can be run either on natural gas or light fuel oil (LFO) and, with certain modifications, also on heavy fuel oil (HFO).
It is supplied in configurations from 6L up to 18V, the latter rated 17.1 MW mechanical output, and is designed to give the same output whether it is running on natural gas or on LFO/HFO. Shaft efficiency is 47 per cent on gas. The engine meets the TA-Luft emissions standard for gas operation, with 500 mg/Nm3 NOx and 420 mg/Nm3 CO (at 5 per cent O2).
The new machine is designed to switch over from gas to LFO and vice versa smoothly while it is operating. For gas, ignition is by pilot injection of fuel oil. The dual fuel concept is the same as that used successfully in the 32DF, while the main components of the 50DF have come from the W46GD machine.
One market being targeted by Wartsila is decentralised power plants, where it is believed the 50DF could successfully take on gas turbines, with, for example, three 18V50DF modules employed in a 50 MW plant. Among the advantages claimed are the ability to use a wide range of fuels, the capability of load upgrading cost effectively by adding modules, less sensitivity to reduced load and high ambient temperatures, and the ability to operate with low (less than 4 bar) gas pressure.