Section 6: Calculation. (20 points) 得分 A moist material is to be dried from water content 30% to 5% (wet basis) in an ad

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Section 6: Calculation. (20 points) 得分 A moist material is to be dried from water content 30% to 5% (wet basis) in an adiabatic dryer (constant enthalpy drying process) under atmospheric pressure. The feed of moist material solid into the dryer is 500 kg/h. After being preheated to 100°C, the fresh air with a dry-bulb temperature of 25°C and a humidity of 0.013 kg water/kg dry air is sent to the dryer, and leaves the dryer at 65°C. (1) What are the bore-dry air (in kg/h) and the volume of fresh air required per unit time (in m³/h)? (2) How much heat is obtained by air when it passes through the preheater (in kJ/h)? (Hint: v= (0.772 +1.244H₂)x 4+273 273 The total enthalpy of wet air is (1.005+1.884Hr+2501H] Taz. H₂ G. To, H₂ Ls, Tn. X 第页共4页