Götaverkan Miljö AB, has announced that it has completed the first commercial installation novel "Sulfur Recirculation" technology in one of the two Waste-to Energy lines at Maabjerg Energy Center in Denmark. Sulphur, separated in the wet flue gas treatment, is recirculated to and injected into the boiler where it converts corrosive alkali chlorides to non-corrosive alkali sulphates reducing high temperature corrosion.
Götaverkan Miljö AB, a Swedish flue gas treatment specialist has announced that it has completed the first commercial installation novel “Sulfur Recirculation” technology in one of the two Waste-to Energy (WtE) lines at Maabjerg Energy Center in Denmark.
Sulphur, separated in the wet flue gas treatment, is recirculated to and injected into the boiler, where it converts corrosive alkali chlorides to non-corrosive alkali sulphates. High temperature corrosion is expected to decrease considerably.
The innovative technology is able to reduce high temperature corrosion in superheaters. Alternatively, it can increase electricity generation at waste incineration installations, if superheater steam pressure and temperature are raised.
Measurements are currently being performed by the High Temperature Corrosion Centre at Chalmers University of Technology, Sweden and Babcock & Wilcox Vølund, Denmark as part of a large research project. The project provides a unique opportunity to compare the corrosion rates in two parallel WtE combustion lines with the same fuel but with and without Sulfur Recirculation respectively.
According to a statement, results thus far suggest that the sulphur recirculation technology has completely eliminated the need for costly transport and disposal of residual sulphate water, since the excess sulphur now ends up in the fly ash. A positive side-effect is that the emissions of several components in the flue gas are further reduced.
Unique two stage process
The technology is unique in that no external sulphur is added and thus the amount of residual products does not rise. In the process, sulphur from a wet flue gas cleaning system is returned to the furnace. The recirculated sulphur raises the sulphur dioxide (SO2) concentration in the furnace and reduces the chlorine/sulphur (Cl/S) ratio in deposits and ashes, and the environment becomes less corrosive.
Furthermore, the formation of dioxin is reduced, and the proportion of sulphates in the effluent water discharged from the wet flue gas cleaning is reduced substantially.
The process works in two stages. First SO2 is removed from the flue gases in the wet flue gas cleaning stage. The removed sulphur compounds are then sprayed into the boiler through nozzles with a surrounding carrier gas. In this way the level of sulphur in the water is raised. Thus each sulphur atom passes through the furnace several times and no external sulphur need be added.
The process has been tested at the Renova waste incineration installation in Gothenburg, Sweden. Measurements were taken in collaboration with Chalmers HTC and SP Technical Research Institute of Sweden with support from Waste Refinery and ProEnivro.
