This project is a part of the development of a biomass fluidized bed combustor connected to an industrial steam boiler. The objectives of the project are to study the characteristics of fluidization and preliminary design of the fluidized bed combustor firing biomass fuel by using sawdust as the fuel and sand as the bed material (diameter of 0.3-0.6 mm) with 40 cm of bed height in the combustor. The circular cross sectional area of about 0.9 m inside diameter of a cylindrical part is selected and a total height of the combustor of about 3 m (conical part of 18 degree cone angle is 1 m high and 4 cylindrical parts are 0.5 m high in each part). The combustor is made from a steel sheet with 4.5 mm thick. There are 5 main components such as, forced draft fan, screw feeder, bed preheating system with LPG burner, dust separator and the air distributor plate of nozzle stand pipes with a bubble cap type. A plate diameter of the air distributor is 0.25 m. There are 9 nozzles with 5 cm high and 2 mm of hole diameter around the nozzle body. In the experimental tests of pressure drop across the bed in the conical part. The study were taking place by selecting 3 conical parts of 15, 22 and 30 degree cone angles. The results have shown that the conical shaped bed can reduce the pressure drop across the bed in the combustor. However, the greater of the cone angle degree or bed height would be led to the spouted bed effect. Additionally, results of the bed preheating tests in a non-insulated combustor shows a bed temperature up to 350oC by taking about 80 minutes.
By
Jakrawut Phanpradidtha
Dusit Opakorn
Idthi Praguyhongsamanee
