This bubbling fluidized bed boiler with 23 MW is suitable for the fuel heat input of fiber sludge, mixed with up to 50% coarse rejects and up to 15% biosludge. The installation has reduced energy costs and eliminated fossil CO₂ emissions by replacing a traveling grate boiler previously fired with lignite briquettes.
To reduce ash disposal costs, an ash pre-separation system with cyclones resides upstream of the flue gas cleaning to obtain ash with fewer pollutants. An SCR system is installed downstream of the dry sorption system and the bag filter to ensure the lowest NOx emissions. As the dry sorption flue gas cleaning operates at 210-220°C, no flue gas preheating is required upstream of the SCR system. For optimized performance and maximum boiler efficiency, heat recovery is implemented with a feedwater preheater downstream of the SCR.