In comparison to other renewable energy sources, thermal
utilization of biomass or waste is a cheap and technically
feasible option to reduce net CO2 emissions. Co-combustion of biomass or waste with coal in existing large-scale firing
systems offers several advantages compared with systems
exclusively fired with biomass. Use of biomass or waste,
however, may have consequences on combustion behaviour,
emissions, corrosion, and residual matter.
Based on previous experience, the objective of this project is to concentrate the research effort on the problem areas of
slagging, fouling, corrosion, ash utilization and trace
emissions by testing different co-combustion systems and to
investigate technical options to avoid these negative effects. Solution of these problems will promote a widespread use of
existing biomass resources.
Two different concepts will be compared with regard to
fouling, slagging, corrosion, ash utilization and trace
emissions. The first and cheapest possibility is direct co-combustion using coal and biomass as feedstock in a coal-fired boiler. Here the effects of co-combustion of different kinds of biomass on slagging, fouling, and corrosion will be
considered. The effects of co-utilization on the ash
composition have also to be evaluated and compared to a pure coal or biomass combustion system. The combustion concepts
under consideration will be fluidized bed combustion,
pulverized fuel combustion, and the slagging combustor.
A further approach is to pre-treat the biomass to remove the undesired components before combustion. One way could be a
pyrolysis/ gasification process and the use of the produced
gas in a different boiler. The gas can be used as reburn fuel for NOx reduction. A maximum gas yield being advantageous, not only pyrolysis but also gasification has to be considered. If the yield of the remaining char is too high, treatment and
combustion of the ash has to be taken into account.
Expected Achievements and Exploitation
The effects of different kinds of biomass on operation,
emissions and residuals and the economics of the different co-combustion concepts will be shown. This will make it possible to define the most suitable technique. The limits of co-combustion will be identified and measures to prevent
operational problems and to reduce environmental effects will be outlined. The results can then be transferred to industrial application; they will enable designers and operators of
combustion plant to minimize the operational and environmental impact of plant burning blends of coal and biomass. The
resulting information will allow development of new plant
designs that offer better control of boiler operation with an associated improvement in environmental performance.
Funding SchemeCSC - Cost-sharing contracts
20500 Turku / Abo
GL52 4RZ Cheltenham
SW7 2AZ London
SW7 2BX London
04425 Plaussig - Leipzig
611 82 Nyköping
611 82 Nyköping
162 87 Stockholm