Lahti Energia and Valmet agree on further development of gasification technology
One of the Finnish environmental technology flagship projects gaining international attention is the new gasification based waste-to-energy plant solution, developed by Valmet. The development work started in Tampere in 2002, has proceeded to a commercial solution for Lahti Energia Oy’s Kymijärvi II power plant, via various demonstration stages. Lahti Energia and Valmet will continue to develop the plant together even after the conclusion of the delivery. Lahti Energia’s effective power plant produces electricity and heat from recycled fuel. The electricity production capacity of the plant is 50 MW and heat production capacity 90 MW. It is among the most modern waste-to-energy combined heat and power facilities in Europe. The harmful components contained in waste can be safely removed before the gas is utilized in a conventional power plant process. This economically feasible method is also extremely efficient and cuts down on the use of fossil fuels.
The electricity generated in a traditional mass burn power plant only amounts to approximately 20% to 25% of the energy content of the waste. Thanks to the gasification technology developed by Valmet, it is now possible to achieve efficiency rates exceeding 30% – in other words, the same amount of waste yields around 30% to 50% more electricity. Efficiency in electricity generation is a major advantage and increases the competiveness of Valmet’s gasification technology in the international markets, as in many countries the heat generated in the production process cannot be utilized for district heating.
Encouraging operational experiences
Lahti Energia’s Kymijärvi II demonstration plant has been in operation for slightly over two years. Since it was the first operational power plant of its kind, the design was based on data obtained through pilot plants. By now it has already become clear that most of the design solutions are successful. Lahti Energia and Valmet have agreed on joint further development of the power plant.
All of the performance specifications required of the plant have been met. There are no symptoms of high-temperature corrosion, in other words, the most important design goal has been achieved.
According to Hemmo Takala, Production Manager of Lahti Energia, some surprises have emerged during long-term use: ”Availability of the plant fell behind the desired level during the first year of operations. The plant has been improved during the maintenance shutdowns during this and previous summer. Already during spring this year, the availability was much better and came close to complying with the set targets.”
Lahti Energia’s Kymijärvi II power plant utilizes hot gas filtering technology that is virtually unique on a global level, resulting in many new insights into the technology. Modifications in the technology and changes in operating methods based on these experiences have improved the performance and reliability of the plant.
”We have learned a lot thanks to this plant, particularly regarding long-term operations, which are impossible to test in a small scale. The experiences obtained have clearly helped in further improving Lahti Energia’s plant. This knowledge also helps us in designing future power plants,” says Juhani Isaksson, Head of Valmet’s gasification technology.
Valmet also develops biomass gasification
In addition to the waste gasification process in use at the Kymijärvi II power plant, Valmet also supplies biomass gasification plants. A large biomass gasification system delivered by Valmet to Vaskiluodon Voima’s power plant, in Vaasa, was inaugurated in March 2013. In early 2014, Valmet additionally received the order for a large biomass gasification plant to be built at OKI Pulp and Paper mills’ new pulp mill in Indonesia (Valmet’s stock exchange release February 7, 2014).