Question

1. Wet solids pass through a continuous dryer. Hot dry air enters the dryer at a rate of 400 kg/min and mixes with the water that evaporates from the solids. Humid air leaves the dryer at 50°C containing 2.44 wt% water vapor and passes through a condenser in which it is cooled to 10°C. The pressure is constant at 1 atm throughout the system. a. At what rate (kg/min) is water evaporating in the dryer? b. Use the psychrometric chart to estimate the wet-bulb temperature, relative humidity, dew point, and specific enthalpy of the air leaving the dryer Use the psychrometric chart to estimate the absolute humidity and specific enthalpy of the air leaving the condenser Use the results of parts (b) and (c) to calculate the rate of condensation of water (kg/min) and the rate at which heat must be transferred from the condenser (kW) If the dryer operates adiabatically, what can you conclude about the temperature of the entering air? Briefly explain your reasoning. What additional information would you need to calculate this temperature? c. d. e.

Answer 1

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