Mass Transfer - Study Mode
[#306] Penetration model (theory) for mass transfer was enunciated by
Correct Answer
(C) Higbie
[#307] For continuous drying of grannular or crystalline material, the dryer used is the __________ dryer.
Correct Answer
(C) Rotary
[#308] Which of the following is the most suitable for extraction in a system having very low density difference?
Correct Answer
(B) Centrifugal extractor
[#309] Which of the following processes is followed by unsaturated air (with dry bulb temperature 12°C and relative humidity 47%) passing through water spray washer (temperature of water being constant at 40°C?
Correct Answer
(C) Both heating and humidification
[#310] An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively.The humidity of air sample expressed as kg of water vapour/kg of dry air is
Correct Answer
(A) 0.048
Explanation
Solution: Given: Dry bulb temperature = 60°C Dew point temperature = 40°C Total pressure = 101.3 kPa Vapour pressure of water at 40°C = 7.30 kPa Vapour pressure of water at 60°C = 19.91 kPa Humidity (H) is calculated using: H = 0.622 × (P v / (P - P v )) Where: P v = partial pressure of water vapour = vapour pressure at dew point = 7.30 kPa P = total pressure = 101.3 kPa Now substituting the values: H = 0.622 × (7.30 / (101.3 - 7.30)) H = 0.622 × (7.30 / 94.0) H ≈ 0.622 × 0.07766 H ≈ 0.0482 kg water/kg dry air Therefore, the correct answer is Option A: 0.048