title: Sulfur recirculation for increased electricity production in Waste-to-Energy plants.
abstract: Sulfur recirculation is a new technology for reducing boiler corrosion and dioxin formation. It was demonstrated in full-scale tests at a Waste to Energy plant in Göteborg (Sweden) during nearly two months of operation. Sulfur was recirculated as sulfuric acid from the flue gas cleaning back to the boiler, thus creating a sulfur loop. The new technology was evaluated by extensive measurement campaigns during operation under normal conditions (reference case) and operation with sulfur recirculation. The chlorine content of both fly ash and boiler ash decreased and the sulfur content increased during the sulfur recirculation tests. The deposit growth and the particle concentration decreased with sulfur recirculation and the dioxin concentration (I-TEQ) of the flue gas was reduced by approximately 25%. Sulfuric acid dew point measurements showed that the sulfuric acid dosage did not lead to elevated SO3 concentrations, which may otherwise induce low temperature corrosion. In the sulfur recirculation corrosion probe exposures, the corrosion rate decreased for all tested materials (16Mo3, Sanicro 28 and Inconel 625) and material temperatures (450 °C and 525 °C) compared to the reference exposure. The corrosion rates were reduced by 60-90%. Sulfur recirculation prevented the formation of transition metal chlorides at the metal/oxide interface, formation of chromate and reduced the presence of zinc in the corrosion products. Furthermore, measured corrosion rates at 525 °C with sulfur recirculation in operation were similar or lower compared to those measured at 450 °C material temperature in reference conditions, which corresponds to normal operation at normal steam temperatures. This implies that sulfur recirculation allows for higher steam data and electricity production without increasing corrosion.
authors.affiliation: Götaverken Miljö AB, Box 8876, SE-402 72 Göteborg, Sweden. Electronic address: sven.andersson@gmab.se.
authors.forename: Sven
authors.initials: S
authors.lastname: Andersson
authors.forename: Evalena W
authors.initials: EW
authors.lastname: Blomqvist
authors.forename: Linda
authors.initials: L
authors.lastname: Bäfver
authors.forename: Frida
authors.initials: F
authors.lastname: Jones
authors.forename: Kent
authors.initials: K
authors.lastname: Davidsson
authors.forename: Jan
authors.initials: J
authors.lastname: Froitzheim
authors.forename: Martin
authors.initials: M
authors.lastname: Karlsson
authors.forename: Erik
authors.initials: E
authors.lastname: Larsson
authors.forename: Jesper
authors.initials: J
authors.lastname: Liske
mesh_terms: D060729:Coal Ash / Q000032:analysis; D003343:Corrosion; D004147:Dioxins / Q000032:analysis; D004560:Electricity; D004736:Energy-Generating Resources; D010316:Particle Size; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives / Q000032:analysis; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods; D013455:Sulfur / Q000032:analysis / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry; D013696:Temperature
chemical_list: D060729:Coal Ash; D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; D013464:Sulfuric Acids; D013455:Sulfur; C033158:sulfuric acid
keywords: (Inductively Coupled Plasma-Atomic Emission Spectrometry); (Inductively Coupled Plasma-Optical Emission Spectrometry); A; Alkali=Na and K; Chlorine/sulfur molar ratio; Cl/S; Corrosion; DLPI; Dekati Low-Pressure Impactor; Dioxins; EDX; Energy Dispersive X-rays; I-TEQ; ICP-AES; ICP-OES; International Toxic EQuivalents; PCDD; PCDF; Polychlorinated dibenzo-p-dioxins; Polychlorinated dibenzofurans; SEM; Scanning Electron Microscopy; Sulfur; Superheater; TEF; Toxic Equivalent Factor; Waste incineration; X-Ray Diffraction; XRD