A spray drier is used to dry skim milk to a final moisture content of 5.00%. The air entering the drier is 1 IOOC, is heated from ambient air at 26.00C and 80.0% RH. The flow rate of hot air entering the dryer is 1000 m3 dry air/min. The skim milk enters the dryer at 45.00C with 55.0% moisture content and the exit temperature is 55.00C. The specific heat of product solids is 2.00 kJ/kg dry solid-OC. The heated air leaves the system at 5.000C above the product temperature. Determine: a. the %RH of air leaving the dryer

A spray drier is used to dry skim milk to a final moisture content of 5.00%. The air entering the drier is 1 IOOC, is heated from ambient air at 26.00C and 80.0% RH. The flow rate of hot air entering the dryer is 1000 m3 dry air/min. The skim milk enters the dryer at 45.00C with 55.0% moisture content and the exit temperature is 55.00C. The specific heat of product solids is 2.00 kJ/kg dry solid-OC. The heated air leaves the system at 5.000C above the product temperature. Determine: a. the %RH of air leaving the dryer

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter50: Commercial, Packaged Rooftop, Variable Refrigerant Flow, And Variable Air Volume Systems

Section: Chapter Questions

Problem 12RQ: Free-cooling can be accomplished if the A. enthalpy of the return air is lower than the enthalpy of...

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A spray drier is used to dry skim milk to a final moisture content of 5.00%. The air entering the drier is 110°C, is heated from ambient air at 26.0°C and 80.0% RH. The flow rate of hot air entering the dryer is 1000 m3 dry air/min. The skim milk enters the dryer at 45.0°C with 55.0% moisture content and the exit temperature is 55.0°C. The specific heat of product solids is 2.00 kJ/kg dry solid-°C. The heated air leaves the system at 5.00°C above the product temperature. Determine: a. the %RH of air leaving the dryer; and b. the production rate of the moist product leaving the dryer. (Note: Obtain necessary properties of air using the psychrometric chart given to you; All moisture content is on wet basis)
A spray drier is used to dry skim milk to a final moisture content of 5.00%. The air entering the drier is 1 IOOC, is heated from ambient air at 26.00C and 80.0% RH. The flow rate of hot air entering the dryer is 1000 m3 dry air/min. The skim milk enters the dryer at 45.00C with 55.0% moisture content and the exit temperature is 55.00C. The specific heat of product solids is 2.00 kJ/kg dry solid-OC. The heated air leaves the system at 5.000C above the product temperature. Determine: a. the production rate of the moist product leaving the dryer. (Note: Obtain necessary properties of air using the psychrometric chart given to you; All moisture content is on wet basis)
A countercurrent tunnel dryer is being used to dry apple slices from an initial moisture content (wet basis) of 65% to 5%. The heated air enters at 95°C with 1% RH and leaves at 52°C. If the product temperature is 20°C throughout the dryer and the specific heat of product solids is 2.2 kJ/(kg °C), determine the quantity of heated air required for drying the product at a rate of 160 kg/h. Determine the relative humidity of outlet air.
6. A countercurrent tunnel dryer is used to dry apple slices from an initial moisture content of 65% to 5% (wet basis). Hot air enters at 95 ° C with 1% RH, and exits at 52.0 ° C. If the product temperature along the dryer is 20 ° C and the solid specific heat of the product is 2.2 kJ / (kg ° C), determine the rate of hot air required to dry the wet product at a rate of 160 kg / hr. Determine the RH of the dryer exhaust air. a. Drying air rate (ma) = kg / hr. b. RH of dryer exhaust air =%
A countercurrent tunnel dryer was used to dry the ape slices from an initial moisture content of 70% to 10% (wet basis). Hot air enters at 95 C with 1% RH, and exits at 60.0 C. If the product temperature at drying length is 20˚C and the specific heat of the product solids is 2.2 kJ / (kg ˚C), determine the rate of hot air required to dry the wet product at a rate of 240 kg / hour. determine the RH of the drying air outlet. a. drying air rate (ma) = kg / hr b. RH of dryer exhaust air = %
Air at dry bulb temperature of 26 Celsius and a RH of 85% is heated to a dry bulb temperature at 100 Celsius . The dryer contains 2300 kg of coconut with an initial moisture content of 67% wet basis. If the average moisture content of the product is 15% wet basis, after drying for 7 hour, with the air flow rate of 1739kg/hr., determine the exit air temperature and relative humidity, and heat requirement in kW. (B). A parallel-flow heat exchanger is used to cool milk (C=3.845 J/Kg. 0C) entering at 110 Celsius. The flow rate of milk is 1.5 kg/s. Cold water (C=4.178 KJ/ kg 0C) enters at 22 Celsius with a flow rate of 3.0 kg/s and exits at 45 0C. The overall heat transfer coefficient is known to be 300 W/m2.0 Calculate (a). The exit temperature of milk(c). Draw the temperature profile of above heat exchanger(b). The heat transfer surface area required
14- In a drying process, the moisture content of 25 kg of food will be reduced from 88% to 8%. The air used for drying enters the dryer at 85 ° C and exits at 70 ° C. 200 kg of saturated steam is used at 120 ° C to heat the air. Food enters the dryer at 30 ° C and exits at 65 ° C. Calculate the drying efficiency for an adiabatic operating dryer as the ambient air temperature is 25 ° C. (specific heat of food = 2.98kj / kg ° C) A.) 30%B.) 25%C.) 17% D.) 12%E.) 33%
The moisture removed from a material is 200 lb/hr and change of humidity ratio of air in the dryer is 105 grains/lbmd.a. Determine the fan capacity in cfm if specific volume of air entering is 38 ft3 /lb.
The small business uses a forced-draught cooling tower for cooling the water of its refrigeration and air conditioning systems. The fan power input is 3 kW. The air enters the cooling tower at 17.5 C and a relative humidity of 50 %. The water from the steam plant enters at 54C and is sprayed into the tower at a rate of 10 kg/s. The water leaving the tower is at a temperature of 25 C. The air leaves the tower at 35C and is saturated. Assume that the whole process occurs at a constant pressure of 85 kPa. Calculate the following: (a) The airflow required in [m3/s]. (b) The make-up water required in [kg/s]
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Pelletized peanut shells have been proposed as a solid fuel for household cookstoves in rural villages in developing countries. The ultimate analysis (wt %, dry) of the peanut shells is given in the image below. Calculate the expected HHV and the LHV if the peanut shells are dry and no binder is added. If the as-received moisture content of the pellets is 10%, and 10% clay (dry basis) is added as a binder, what will be the LHV of the pelletized fuel? If the cookstove efficiency is 18%, what weight of pellets (with binder) is required to heat 2 L of water from 20°C to 100°C?
Using a psychrometric diagram, describe the heating and humidification process from the following data. Initially the air was at a dry bulb temperature (DBT) of 30 ° C and RH60%. The air is heated to DBT 80 ° C. The heated air is then flowed through a humidifier to increase the RH to 25%. For this process, calculate,a. Change in absolute humidity of air from initial to final conditions = (kg water / kg air).b. The change in air enthalpy from initial to final conditions. = (kJ / kg air)