Impact of co-combustion on emission behaviour and ash quality by co-firing high shares of Biomass and Residues

摘要

Coal is burnt in power plants and industrial installations in large quantities with an increasingtendency due to the increasing world-wide energy consumption despite the necessity to reduce or evenstabilise the overall CO_2 emissions. Therefore, the utilisation of biomass as well as residues in existingcoal fired power stations is an important way to achieve internationally agreed overall targets for thereduction of greenhouse gas emissions.The large majority of biomass co-firing power plants, currently in operation over Europe, areassociated with retrofit applications on existing coal-fired power plants. This fact clearly influencedthe decision towards fuel specification and maximizing biomass co-firing shares. For new buildapplications, the situation is somewhat different and the scope may be significantly more ambitious interms of the range of biomass fuels fired and the maximum co-firing ratio that can be achieved.In the frame of the European project DEBCO the demonstration of different and advanced co-firingapplications is co-funded. To evaluate the impact of co-firing on the boiler performance, the flue gascleaning devices, and the stack emissions a substantial measurement plan was created and will bedescribed to evaluate possible impacts. In addition, the publication will present some first results offull scale measurements in a large scale plant (250MW) co-firing up to 100% wood pellets. Besidesthe monitoring data of the plant, dedicated measurements in the burner and the super heater area, aswell as along the flue gas path, have been performed. In addition, fuel and fly ash samples have beentaken and analysed to evaluate their impact on the combustion and emission behaviour.