Finnish engine manufacturer Wärtsilä has unveiled its latest product offering for the power generation industry – the 50DF engine. The new unit has dual fuel capability and will be aimed mainly at decentralized cogeneration applications.


The new 50DF dual-fuel engine will have advantages over gas turbines in decentralized cogeneration applications
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Wärtsilä unveiled the 50DF at its manufacturing plant in Trieste, Italy, where the new engine has been undergoing endurance testing on a test bed facility. The company has already sold its first 50DF unit to Gaz de France.

The 50DF is based on Wärtsilä’s existing 46 engine. It is available in 6-, 8- and 9-cylinder in-line configurations, and also in 12-, 16- and 18-cylinder Vee configurations. Cylinder output is 950 kW and the engine speed is 500 or 514 r/min.

The new engine can run on natural gas or diesel fuel and can switch between the two fuels either automatically (i.e. during alarm situations) or by manual operation. The engine can reach 100 per cent load on either fuel. When in gas mode, the engine can transfer to diesel operation at any load, while in diesel mode, it can transfer to gas operation at loads of up to 80 per cent.

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Wärtsilä has designed the engine mainly for decentralized power production applications where high efficiencies can be achieved through the recovery of waste heat. And with an output of up to 17 MWe, the 50DF will compete directly with gas turbines in distributed generation applications.

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Gas engines have dominated the lower ranges of distributed generation (1-7.5 MW), while gas turbines have dominated the higher ranges (7.5-30 MW). Wärtsilä believes that the 50DF will change this due to the advantages that gas engines have over gas turbines:

  • Lead times of 8-12 months
  • Low gas pressure demand
  • Easy and fast to start and stop
  • Maintenance possible by plant staff
  • HFO as back up fuel and fuel flexibility
  • Small footprint.

Wärtsilä new 50DF engine range has an output of 5.7 MW-17.1 MW
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Wärtsilä has been testing an 18-cylinder version of the 50DF in Trieste, running it on natural gas fuel with light fuel oil as a pilot fuel. Component inspections after 450 hours of operation found no wear or problem with the pistons, big end bearing, injection nozzle, gas admission valve and other parts.