5. A fluidized bed dryer is being used to remove water at the end of the manufacturing process of a pharmaceutical drug. The pharmaceutical enters at 25C with a moisture content of 50% on a wet basis (i.e. 50% of the weight of the wet solid is water). Ambient air at 20C and 60% percentage humidity is heated to 97.5 C before being let into the dryer. Estimate the production rate of dried pharmaceutical (defined as pharmaceutical with 5% moisture content on a wet basis) and the percentage humidity of the exiting air for an air feed rate of 700 kg dry air/hr. Assume that the pharmaceutical has a specific heat of 2.5 kJ/(kg dry solid C) and exits the dryer at the air wet bulb temperature. Air exits the dryer 10C warmer than the pharmaceutical. The heat capacity for water in the pharmaceutical is 4.2 kJ/kg, and the enthalpy of water-air mixture is a = h (4.) = (1.005 + 1.88H)(T (C) Tref) + 2501.4 H where H is the humidity and Tref is 0 C. Use the humidity chart 2 in this problem. kg Humidity chart 1 LLLLLLL 180 170 160 Enthalpy 150 140 - 130 120 110 100 909 809orh 65 90 7000h Btus per pound - 21.1.2017.12.2011 14 15 16 17 18 19 20 21 22 23 24 25 Drees Fahrenheit--wet-bulb or dew-point temperatu 66% th Grains water vapor per pound of dry air-absolute humidity 80 60 50%h - 70 40th (% 30% rh - 60 50 2096 h - 50 40 10%rh OE- - 20 10 0 0 35 40 45 50 65 55 09 70 75 80 85 06 95 100 105 105 120 110 Degrees Fahrenheit-dry-bulb temperature 1 grain = 0.000143 lbm = 0.0648 g (7000 grains per lbm) 0.15 adiabatic saturation curve 0.14 Humidity chart 2 0.13 1 percentage humidity - 0.12 A 100% - 0.11 -%064 1 80% L 7035 109,- 50% 40%. 30% - %02 0.10 10% 5% 1 0.09 0.08 0.07 Humidity, H (kg water vapor/kg dry air) 0.06 0.05 0.04 0.03 0.02 0.01 0 10 20 30 40 50 0 130 100 - 110 120 60 70 80 90 Temperature (C)