| Abstract |
The application of Dry Sorbent Injection (DSI) desulfurization with sodium bicarbonate was investigated to reduce SO2 emission from power sector. The sorbent was injected directly into the combustion chamber of the 29 MWth grate boiler, into a non-standard area of high temperature (approximately 700 degrees C), while generally the DSI method is carried out in the flue gas duct with a temperature below 250 degrees C. Unique nozzle design for injecting powdery sorbents was implemented and two stoichiometric ratios were tested: NSR = 1.1 and NSR = 3.0. The reduction of SO2 from a base level of 1580 mg SO2/Nm3 to 301 mg SO2/Nm3 at 6% O2 was achieved, resulting in a process efficiency of 81%. The chemical properties of fly ash were determined in terms of its safe storage and potential use according to the principles of the circular economy. Ash formed during the desulfurization process shows a different chemical composition than the reference sample. A significant increase in the concentrations of the following components and parameters was indicated: S, Na, Zn, Cu, As, Mo, Pb, loss of ignition (LOI) and total organic carbon (TOC). The change in chemical composition led to an increase of total dissolved matter (TDS) in water leachate as well as sulphates, chlorides, fluorides, As, PB, Cu and Zn concentrations. |
