Germany – Heat-transfer station construction work – Abwärmenutzung Rauchgas RABA Erfurt-Ost, Los 2 Generalunternehmer für Planung, Herstellung, Lieferung, Errichtung und Inbetriebnahme einer Rauchgaswärme-Nutzungsanlage

SWE UmweltService GmbH (SWE US) is a company of the Stadtwerke Erfurt Group (SWE) and operates the Residual Waste Treatment Plant (RABA) at the Erfurt-Ost site. The RABA was constructed in 2006 and is a combination plant consisting of a Mechanical Treatment Plant (MBA), an Energy Recovery Plant (EnVA) and a Sewage Sludge Drying Plant (KTA). In the RABA, a 3-pass boiler thermally processes waste at a throughput of 9.75 t/h. After exiting the boiler, the RABA's flue gas is directed to the flue gas cleaning system. There, the flue gas is post-treated using Ca(OH)2 and HOK. Fabric filters are used to remove dust from the flue gas. Finally, the cleaned flue gas is directed to the silencer and chimney via an induced-draft fan. At the exit of the induced draft, the flue gas has a temperature of approximately 145 °C. The thermal input is 26 MWth. The generated steam is used to drive an extraction-condensing turbine with an electrical output of 4 MWe and for the drying of sewage sludge. The condensation of the exhaust steam is carried out with an air condenser (Luko). To increase the energy efficiency of the RABA and to reduce CO2 emissions, the RABA is to be extended by a flue gas heat recovery (RGWNutz-Anlage) plant. A flue gas heat exchanger is to be arranged between the induced-draft outlet and the silencer inlet of the existing plant to generate district heating water for the district heating supply of the city of Erfurt. The existing flue gas duct is to be replaced by the flue gas heat exchanger. District heating water pipes with the necessary pipe bridge are to be installed to connect to the existing district heating water network of SWE Energie GmbH (SWE E). The connection to the district heating water network is to be made indirectly with a coupling circuit to ensure independent operation of RABA and district heating water network. The necessary process engineering plants, electrical and control engineering as well as construction services are to be planned, supplied, erected, tested, commissioned and documented by the contractor. The aim is to reduce the flue gas temperature to as low as 80 °C during full-load operation of the RABA and to transfer at least 1.1 MWth to the district heating water network.