Experiences on Co-firing Solid Recovered Fuels in the Coal Power Sector

Solid Recovered Fuels (SRF) are solid fuels prepared from high calorific fractions of non-hazardous waste materials intended to be fired in existing coal power plants and industrial furnaces (CEN/TC 343, Solid Recovered Fuels, 2003). In other frameworks, these types of fuels are referred to as refuse or waste derived fuels. They are composed of variety of materials of which some, although recyclable in theory, may be in forms that made their recycling an unsound option. The use of waste as a source of energy is an integral part of waste management. As such, within the framework of the European Community’s policy-objectives related to renewable energy, an approach to the effective use of wastes as sources of energy is outlined in documents like the European Waste Strategy. Within the scope of the European Demonstration Project, RECOFUEL, SRF co-combustion was demonstrated in two large-scale lignite-fired coal boilers at RWE in Germany. As a consequence of the high biogenic share of the co-combusted material, this approach can be considered beneficial following European Directive 2001/77/EC on electricity from renewable energy sources (directive). During the experimental campaigns, the share of SRF in the overall thermal input was adjusted up to 15%. The measurement campaign included boiler measurements in different locations, fuel and ash sampling and its characterization. The corrosion mechanisms and rates were analysed and monitored by dedicated corrosion probes. The scope of this chapter covers the characterisation of SRF using the pre-nominative technical specifications of CEN and the status of the standardization activities. Additionally this chapter summarizes some of the experiences gained from co-firing of SRF and biomass in large scale demonstration plants. These include handling and pretreatment of the SRF, milling corrosion, emissions behaviour, and the quality of solid residues.