Pyrolysis technology has been developed in Finland since the 1990s. It involves heating wood to a temperature of 550 - 600 degrees, when it evaporates into gases that condense into pyrolysis oil as they cool. The pyrolysis method used in Fortum’s new plant has been developed by Metso Power, Fortum, UPM and VTT Technical Research Centre of Finland.
Finland’s Ministry of Employment and the Economy has given Fortum an energy support grant of EUR 8.1 million for the construction of the pyrolysis plant. The novelty of the project is that it cost-efficiently integrates the pyrolysis plant with a fluidized bed boiler plant where the non-condensable gases and coke produced during the pyrolysis process can be combusted. This also produces cheap heat for the forest residue dryer.
Pyrolysis oil can be used to replace heavy fuel oil in boilers but requires some modifications in existing district heating plants, which Fortum is carrying out during the construction of the new plant. The switch to pyrolysis oil will enable Fortum to cut its annual carbon dioxide emissions by 59,000 tons and also to reduce sulphur dioxide emissions caused by fuel oil by 320 tons.
Source: Ministry of Employment and the Economy