LOCAL HEAT-TRANSFER, SOLIDS CONCENTRATION AND EROSION AROUND MEMBRANETUBES IN A COLD MODEL CIRCULATING FLUIDIZED-BED

Measurements of local solids concentration, heat transfer and erosion were obtained itt a 152 mm diameter x 9.3 m tall circulating fluidized bed operated at room temperature with 200 mu m. sand: particles at a superficial gas velocity of 7.0 m s(-1) With different Solids circulat ion rates. Local solids concentrations were found to be higher in the fin region than on the crests of membrane tubes. For the small heat tr ansfer Surfaces investigated, this led to higher local heat transfer c oefficients in the fin region,, a trend which is the reverse of that f or long heat transfer surfaces. Erosion rates were-higher on the tube crests than on the fins.