|Design of a Suspension Burner System for Forestry and Agricultural Residues (NRI)|
A schematic diagram of the fuel/air flow is shown in Figure 2. The furnace is pre-heated by a small wood fire built on the floor of the combustion chamber. Sawdust is blown tangentially into the upper half of the furnace and the fuel/ air mixture follows a cyclonic path, spirals to the base of the furnace chamber, up through a vortex and out via a duct located at the top of the furnace. The fuel rapidly oxidizes and the majority of ash residue is carried out of the furnace by the flow of combusted gases and excess air.
Figure 2 Fuel/air flow through the furnace
The hottest region of the furnace is approximately 1000°C. The flue gases pass through the heat exchanger, raising the cooling air temperature by approximately 60°C. The flue gases exit the heat exchanger at approximately 250°C.