Omblandning av råmaterial för hållbar energiomvandling i cirkulerande fluidiserade bäddar

Abstract

To streamline the energy conversion of biomass to power, heat and biofuels in order to break the fossil fuels dependency is of great societal interest. In accordance with this, this work aims to contribute with new knowledge concerning mixing of biomass in circulating fluidized beds (CFB). The experimental setup that the work makes use of consists of a fluid-dynamical downscaled CFB cold model in scale 1:13 compared to a commercial 200 MW boiler, a magnetic particle tracking system and a trace particle. The result of this work shows that (i) There exists a flow structure in the model’s chamber that emerges from the inflow of solids; (ii) The fluidization velocity affects the flowstructure’s shape; (iii) There is a stagnant zone in the chamber. During low pressure difference in the chamber the trace particle gets stuck in the stagnant zone and there exists a threshold value in pressure difference for which the tracer particle can leave the zone. These conclusions call for further research about flow structures inside CFBs.