1997

Wilen, Carl; Kurkela, Esa

This report reviews the development of the biomass gasification technology in Finland over the last two decades. Information on Finnish biomass resources and use, energy economy and national research policy is provided as background. Global biomass resources and potential energy from biomass markets are also assessed based on available literature, to put the development of the gasification technology into a wider perpective of global biomass utilisation for energy production. The increasing use of biomass and other indigenous forms of energy has been part and parcel of the Finnish energy policy for some twenty years. Biomass and peat account for almost 20% of the production of primary energy in Finland. As the consumption of biofuels is significantly lower than the annual growth or renewal, the use of bioenergy is considered to be an important measure of reducing carbon dioxide emissions. Research and development on thermal gasification of solid fuels was initiated in the late 1970s in Finland. The principal aim was to decrease the dependence of Finnish energy economy on imported oil by increasing the utilisation potential of indigenous fuels. De-velopment in the early 1980s focused on simple atmospheric-pressure fuel gas applications including a gasification heating plant. Eight Bioneer updraft gasifiers (abt 5 MWth) were constructed in 1982 - 1986, and a new Bioneer gasifier was commissioned in eastern Finland in 1996. A Pyroflow circulating fluidised-bed gasifier was also commercialised in the mid-1980s; four gasifiers (15 - 35 MWth) were commissioned. In the late 1980s the interest in integrated gasification combined-cycle (IGCC) power plants, based on pressurised air gasification of biomass and hot gas cleanup, increased in Finland and in many other countries. The utilisation potential for indigenous fuels is mainly in medium-scale combined heat and electricity production (20 - 150 MWe). Foster Wheeler Energia Oy, Carbona Inc. and Imatran Voima Oy are the main gasification tech-nology developers in Finland. In 1993, a biomass IGCC demonstration plant based on Foster Wheeler gasification technology and owned by the Swedish utility company Sydkraft was commissioned in Sweden. The plant is the first combined-cycle plant for generating electricity from fuel gas produced entirely from biomass. Atmospheric-pressure gasification of biomass fuels is a simpler and cheaper technology than pressurised gasification. Co-combustion is a promising new alternative, in which the biomass gasification is integrated to a pulverised coal-fired boiler. The concept will be demonstrated by Foster Wheeler Energia Oy and a municipal power company.