抄録
For reduction of dioxins in MSW (Municipal Solid Waste) incinerators, complete combustion by thorough mixing of combustion gas with oxygen supplied as primary and secondary air is important. So far we have realized a very low dioxins level with our unique mixing concept. However, as it is getting required to reduce dioxins concentration to further lower level, another effort had to be made to give a furnace configuration and air supply enabling better gas mixing.
In evaluating the gas flow in a furnace, CFD (Computer Fluid Dynamics) and/or flow visualization in a miniature are generally used. However, both approaches have such problems that the former could not give a precise turbulent pattern and the latter gives only qualitative solutions. Applying PTV (Particle Tracking Velocimetry) method to flow visualization, we found mean turbulence intensity in the mixing zone useful as a quantitative mixing indicator. By employing the indicator we have determined a furnace configuration including air injection which enables much enhanced gas mixing.
