A 25 wt% solution of coffee in water at 70oF is spray-dried to a moisture content of 5% (dry basis) with air entering at 450oF and 1 atm with a humidity of 0.01 lb/lb (dry basis) and exiting at 200oF. Assuming the specific heat of coffee=0.3 Btu/lb-oF, calculate: (a) air rate in lb dry air/lb coffee solution; (b) temperature of evaporation; (c) heat-transfer rate in Btu/lb coffee solution

(For numbers Il to 14) A thick-walled tube of stainless steel [k = 19 W/m°C] with 2-cm inner diameter (ID) and 4-cm outer diameter (00) is %3D covered with a 3-cm layer of asbestos insulation [k = 0.2 W/m.°C]. The inside wall temperature of the pipe is maintained at 600 °C and the outside wall temperature is maintained at 100 °C. 11. What is the log mean area per l-m length of the stainless-steel tube? a. 0.090647 m2 b. 0.181294 m? c. 0.205716 m? d. 0.228768 m? 12. What is the log mean area per l-m length of the asbestos insulation? a. 0.090647 m? b. 0.181294 m? c. 0.205716 m? d. 0.228768 m? 13. What is the rate of heat loss per l-m length of the pipe? a. 586.15 W/m b. 600.10 W/m C. 680.30 W/m d. 759.60 W/m 14. What is the temperature at the tube-insulation interface? a. 596.05 °C b. 592.58 °C C. 588.87 °C d. 584.25 °C

A counterflow tunnel dryer was used to dry the 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 temperature of the product throughout the dryer is 20 °C and the specific heat of the solid 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/hour. Determine the RH of the air exiting the dryer. a. Drying air rate (ma) = Answer kg/hour. b. Dryer exhaust air RH = Answer %

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 200 kg / hr. Determine the RH of the dryer exhaust air. a. Drying air rate (ma) = kg / hr. b. RH of dryer exhaust air =%

Pharmaceutical industry requires evaporation of excess water after productionof the active ingredient. For paracetamol tablets formulation, the medication pastehas 42% water content and should lose 80% of water volume upon exposure toambient air with RH= 0.2 blowing stream for half a day. If a heater was used toobtain hot air at 90°C with the same saturation. Do you think the hotter air wouldenhance the drying of the paste? Justify your answer

A flexible artificial lung is used to study the inflation of the lungs. The device is pre-filled with 8g of air.To mimic physiological conditions, enough heat is then added to the device such that it’s temperature increases from 25 degrees Celsius to 37 degrees Celsius. a) What is the total work done by the air during this process? b)Prove that the amount of heat added is equal to the change in enthalpy of the air. c) How much heat was added during the process? d) what is the change in internal energy of the air ?

Seven thousand lb/h of wet, pulverized clay particles with 27% moisture (dry basis) at 15oC and 1 atm enter a flash dryer, where they are dried to a moisture content of 5% (dry basis) with a cocurrent flow of air that enters at 525oC. The dried solids exit at the air wet-bulb temperature of 50oC, while the air exits at 75oC. Assuming the specific heat of clay=0.3 Btu/lb-oF, calculate: (a) flow rate of air in lb/h (dry basis); (b) rate of evaporation of moisture; (c) heattransfer rate in Btu/h.

A filter cake of Calcium Carbonate contained in a tray is to be dried by cross-circulation from the top surface. Each tray is 2.5 cm high with an area of 1.5 m² and is completely filled with 73 kg of wet filter cake having a water content of 30% on dry basis, The heating medium is air at 1 atm and 170°F with a humidity of 0.026 (kg H,O/kg dry air). The average velocity of the air passing across the wet solid is 4 m/sec. Estimate the time in hours to reach the experimentally determined critical moisture content of 10% on the dry basis, if the preheat period is neglected. Assume latent heat of evaporation of water 2500 kJ/kg.

Q3(a) A stream of benzene vapor at 580 °C and 1 atm is cooled and converted to a liquid at 25 °C and latm in a continuous condenser. (i) (ii) Illustrate a completely process path for the above process. Calculate the total enthalpy change for this process.

Use the thermo table then calculate.