A tunnel drier is used for drying a filtered cake of amino acid crystals for 2 hours using air at 28C. The dimensions of the drying cake are diameter 75 cm and thickness 5 mm. The original crystal solids contained 24% (w/w) of moisture measured on a wet basis. The critical moisture content of the crystals is 15% wet basis and the density of completely dried material is 1380 kg m. The heat transfer coefficient for gas-phase heat transfer to the surface of the crystals is 34 J s m 2C. For the final product, the temperature at the wet crystal surface is 24C and the crystal equilibrium moisture content is 7.5%, dry basis. a) What is the drying rate? b) What is the moisture content of the dried crystals? (Steam table is provided in the Appendix) [8%] [7%] Temperature (0) 0.01 (triple point) 2 4 6 8 10 12 14 16 18 20 22 24 25 26 Pressure (kPa) 0.611 0.705 0.813 0.935 1,072 1.227 1.401 1.597 1.817 2.062 2.34 2.64 2.98 3.17 3.36 Saturated liquid +0.0 8.4 16.8 25.2 33.6 42.0 50.4 58.8 Specific enthalpy (kJ kg-) Evaporation (Ah) 67.1 75.5 83.9 83.9 100.6 104.8 108.9 2501.6 2496.8 2492,1 2487.4 2482,6 2477.9 2473.2 2468.5 2463.8 2459.0 2454.3 2454.3 2444.9 2442.5 2440.2 Saturated vapour 2501.6 2505.2 2508.9 2512.6 2516.2 2519.9 2523.6 2527.2 2530.9 2534.5 2538.2 2538.2 2545.5 2547.3 2549.1