EXPERIMENTAL-STUDY ON A BENCH-SCALE, BATCH-TYPE FLUIDIZED-BED COMBUSTOR FOR ENERGY-PRODUCTION FROM WASTE-DERIVED FUELS

We report experimental results on a bench-scale, atmospheric fluidized-bed combustor with batch feeding of solid fuels. The combustor has an inside diameter of 10 cm and is 1.5 m high; it is provided with a packed-bed, sandwich-type air distributor. Cooling water is circulated in tubes that are partially immersed in the fluidized bed to control the bed temperature during the combustion experiments. Measurements of the pressure drop and temperature were made at different locations in the combustor. The fuels used were naturally available coal with 3.5% sulfur, petroleum coke, and corncobs. Silica sand was used as the inert-bed material. Test runs lasting 40 hours were carried out to study the hydrodynamics and combustion processes in the fluidized-bed combustor. The cold-flow tests included investigations of the effects of the material and size of the bed particles on the fluidization characteristics. Tests were carried out to study the combustion of coals and corncobs at temperatures as low as 650-degrees-C. Temperature uniformity was verified and the heat-transfer coefficient was estimated between the bed and tubes. Values of 600 W/m2 -K are typical of fluidized-bed combustion and were obtained for average bed temperatures from 400 to 800-degrees-C.