A fluidized bed combustor is 2 m in diameter and is fed with air (MW=29) at 250\\\\deg F, 10 psig,\ at a rate of 2000 SCFM. The coal has a density of 1.6 g/cm3 and a sphericity of 0.85. The flue\ gas from the combustor has an average MW of 35 and leaves the combustor at a rate of 2100\ SCFM at 2500\\\\deg F and 1 atm. What is the size range (in m) of the coal particles that can be\ fluidized in this system? Use the mean values for the velocity and density to be used in the\ Ergun equation.