For which one of the following situations would Kendall’s tau be appropriate? a) The Mohs scale rates the hardness of minerals. If one mineral can scratch another, it is judged….
calculate the time in the dryer in the constant-rate zone and the falling-rate zone.
Drying in a Continuous Tunnel Dryer. A rate of feed of 700 lbm dry solid/h containing a free moisture content of X1 = 0.4133 lb H2O/lb dry solid is to be dried to X2 = 0.0374 lb H2O/lb dry solid in a continuous-counterflow tunnel dryer. A flow of 13 280 lbm dry air/h enters at 203°F with an H2 = 0.0562 lb H2O/lb dry air. The stock enters at the wet bulb temperature of 119°F and remains essentially constant in temperature in the dryer. The saturation humidity at 119°F from the humidity chart is HW = 0.0786 lb H2O/lb dry air. The surface area available for drying is (A/LS) = 0.30 ft2 /lbm dry solid.
A small-batch experiment was performed using approximately the same constant-drying conditions, air velocity, and temperature of the solid as in the continuous dryer. The equilibrium critical moisture content was found to be XC = 0.0959 lb H2O/lb dry solid, and the experimental value of kyMB was found as 30.15 lbmair/h · ft2. In the falling-rate period, the drying rate was directly proportional to X.
For the continuous dryer, calculate the time in the dryer in the constant-rate zone and the falling-rate zone.