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Sulphur recirculation is an unique technology for decreasing the corrosion rate for super heaters or, if pressure and temperature is raised after super heaters, for increasing the electricity production in waste-to-energy plants.
The innovative sulphur recirculation process, for which Götaverken Miljö has a world-wide exclusive license, was invented by Hans Hunsinger at Karlsruhe Institute of Technology (KIT). It has previously been tested in the KIT 0.5 MW waste incineration pilot plant "TAMARA". The purpose of the patented process is to reduce the corrosion rate of the super heaters in waste-to-energy plants. This is achieved by recirculating sulphur from the wet flue gas cleaning back to the boiler. The recirculated sulpur will increase the gas concentration of SO2 in the boiler and decrease the Cl/S ratio of the deposits and ashes, thus producing a less corrosive environment for the super heaters. Additionally, the dioxin formation decreases.
Götaverken Miljö AB has successfully demonstrated sulphur recirculation during nearly two months of full-scale operation at the Renova municipal waste-to-energy plant in Göteborg, Sweden. Corrosion probe measurements showed that the corrosion rate for super heater material was less than half with sulphur recirculation in operation. The measurements were carried out in co-operation with Chalmers HTC and SP with support from WasteRefinery and ProEnviro.
Other studies have shown a beneficial effect on corrosion by dosing sulphur as an additive to the combustion chamber. This technology is, however, unique in the way that it, contrary to other methods, only uses the existing sulphur in the fuel and does therefore not increase the amount of residues produced.
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