FUEL FLEXIBLE AND LOW-EMISSION BIOMASS COMBUSTION BY COMBINATION OF FUEL ADDITTVATION AND COMBUSTION RELATED PRIMARY MEASURES

The demand for wood fuels for biomass heating and CHP plants is steadily increasing, thus the prices also rise accordingly, which results for more and more plant owners in economic problems. The utilisation of non-wood biomass fuels, e.g. Miscanthus, grass and agriculture residues such as straw, com cobs or sunflower husks would be a possible alternative, but due to ash-related problems (slagging, deposit formation, corrosion and enhanced particulate matter emissions) these fuels cannot be used in conventional biomass heating systems designed for wood fuels so far. Within a nationally funded Austrian research project a new, fuel flexible and low-emission combustion technology in the power range from 300 to 1,000 kWth for ash-rich fuels with low ash melting temperatures (non-wood biomass fuels) has been developed. The application of optimised fuel additivation in combination with combustion related primary measures (appropriate air staging and bed cooling) form the basis to overcome ash- related problems. Test run results show that this technological approach provides significantly enhanced fuel flexibility at reduced emissions, compared to present state-of-the-art systems for small- to medium-scale applications without cost intensive secondary measures. With the technological additional fuel assortments (non-wood biomass fuels) may be utilised in an economically competitive way, which enlarges the available biomass fuel potential and increases the flexibility for the user.