An air-vapor mixture exhibits wet and dry bulb temperatures of 25°C and 30°C. Upon isobaric heating to 45°C, the wet-bulb temperature becomes ______________ °C ?
Show answer Hide answer
Answer: B. > 25
Explanation
Adding thermal energy isobarically to an air-vapor mixture increases its overall system enthalpy. The wet-bulb temperature rises correspondingly as sensible heat is transferred to the fluid. Psychrometric principles dictate that heating unsaturated air increases both dry and wet bulb values. Isobaric heating maintains constant pressure while raising the thermodynamic temperature of the gas. Air-vapor mixtures combine dry air with varying amounts of evaporated water vapor. Wet-bulb temperatures are measured using thermometers wrapped in wetted wicks exposed to air.
Air conditioning systems frequently heat air streams after humidification or cooling stages. Industrial drying technology utilizes heated air to enhance moisture removal rates from solids. Accurate psychrometric calculations ensure efficient thermal management in chemical processing plants. A constant wet-bulb temperature occurs exclusively during adiabatic saturation and humidification processes. Falling wet-bulb temperatures require evaporative cooling rather than external sensible heat addition. Negative temperature values are completely irrelevant to standard ambient air heating systems.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. To attain high distillation tray efficiency, operators must ensure___________________?
Show answer Hide answer
Answer: A. Interfacial surface between liquid and gas phase should be large
Tray efficiency improves when vapor and liquid have extensive contact area for mass transfer. A large interfacial surface area accelerates the rate of component transfer between phases. Maximizing contact area ensures th...
Q2. The specific temperature to which a vapor-gas mixture must be cooled (at constant humidity) to reach saturation is termed the ______________ temperature?
Show answer Hide answer
Answer: D. None of these
The temperature to which a vapor-gas mixture must be cooled at constant humidity to reach saturation is called the dew point temperature.
Q3. A gas-vapor mixture has wet-bulb and dry-bulb temperatures of 25°C and 30°C. If heated to 45°C isobarically, the resulting wet-bulb temperature will be ______________ °C?
Show answer Hide answer
Answer: B. > 25
Isobaric heating of an unsaturated mixture adds sensible heat and raises total system enthalpy. The thermodynamic wet-bulb temperature increases in response to the higher sensible gas temperature. Psychrometric relations...
Q4. Petroleum refinery distillation columns of 10-12 ft diameter typically maintain tray spacing around _____________ inches?
Show answer Hide answer
Answer: B. 30
Standard industrial practice dictates specific tray spacings to prevent liquid entrainment between stages. A tray spacing of thirty inches provides sufficient disengagement height for vapor-liquid disengagement. Design g...
Q5. Operating a fractional distillation column at total reflux minimizes the____________________?
Show answer Hide answer
Answer: B. Number of plates
Total reflux returns all condensed overhead product back into the top of the distillation column. Recycling all distillate maximizes the internal liquid traffic and enriches concentration profiles rapidly. This condition...
Q6. To boost the absorption factor (where G = gas rate, S = solvent rate) in an absorber, one should ____________________?
Show answer Hide answer
Answer: C. Increase ‘S’ and decrease ‘G’
The absorption factor is mathematically defined as the liquid solvent rate divided by gas rate. Increasing the solvent rate S directly increases the numerator of the absorption factor expression. Decreasing the gas rate...