A technique that enables the cost-effective cogeneration of heating energy and bio-oil in the same power plant has been developed by VTT Technical Research Centre of Finland, along with the energy company Fortum, engineering company Metso and forest products producer UPM. VTT’s technique is based on combining pyrolysis and fluidized bed technology.
VTT feels the new technique will contribute to an increase in bio-oil production volumes in the next few decades. VTT received an innovation award for the new technology from the European Association for Research and Technology Organisations EARTO.
“The innovation prize brings up the long-term work that VTT has done in developing renewable energy sources. EARTO wants to reward innovations that have significant societal and economic impact. The prize indicates that we have been successful in this work,” says Anne-Christine Ritschkoff, executive vice-president, strategic research, VTT.
The new technique patented by VTT enables a considerable cut in the production cost of bio-oil.
Fast pyrolysis involves heating biomass such as forest industry waste to a high temperature to form gas. When the gas is cooled, it condenses into liquid known as bio-oil. Combining the pyrolysis process with traditional fluidised bed boilers used in power plants brings a range of efficiency gains, VTT explains. Producing bio-oil with the new technique is cheaper than in a separate pyrolysis process.
Bio-oil plants that are integrated into power plants are extremely energy-efficient, because the energy contained in the by-products of the pyrolysis process can be recovered in fluidized bed boilers. This is a significant improvement, because the by-products can contain as much as 40% of the original biomass’s energy. In turn, lost heat from the power plant can be used in the bio-oil production process.
The technique is due to enter commercial production towards the end of 2013 when the energy company Fortum opens its new integrated bio-oil and heating plant in the city of Joensuu in Finland. The plant is designed to produce 50,000 tonnes of bio-oil per year.
According to VTT, there are currently around 200 power plants in Europe and North America that could be converted to include a bio-oil plant.