1. In which industry are tunnel truck dryers mostly used?
- 1) Chemical industry
- 2) Ceramic industry
- 3) Textile industry
- 4) Pharma industry
Answer: 2)
Explanation: The use in the chemical industry is less common, it is mainly used in the ceramic industry to dry potteries.
2. What is the drying time in the tunnel truck dryer?
- 1) The sum of all time taken by all the trucks
- 2) The sum of all time taken by all tunnels
- 3) The time taken by each truck
- 4) The time taken by each tunnel
Answer: 1)
Explanation: The drying time is the sum of the time taken by all the trucks.
3. What leads to uneven drying in belt or conveyer dryer?
- 1) High moisture retaining solids
- 2) Maldistribution of air
- 3) High speed of belt
- 4) Change in speed of belt
Answer: 2)
Explanation: The maldistribution of air causes uneven drying in belt dryer.
4. For what solids is belt dryer used?
- 1) Dry
- 2) Wet
- 3) Smooth
- 4) Coarse
Answer: 4)
Explanation: Belt dryer is generally suitable for coarse materials. That is materials in form of granules, pellets.
5. Which are the most used dryers in chemical industry?
- 1) Belt dryers
- 2) Rotary dryers
- 3) Truck dryers
- 4) Tunnel dryers
Answer: 2)
Explanation: Rotary dryers are called as workhorse of chemical industry and are most popularly used.
6. Why is a low flow rate of air maintained in a rotary dryer?
- 1) To carry away the evaporated water
- 2) To evaporate the water
- 3) To increase the speed of crystallization
- 4) To carry forward the crystals
Answer: 1)
Explanation: A low flow rate of air or an inert gas is maintained to carry away the evaporated water.
7. What is the heat efficiency of a rotary dryer?
- 1) 20%-80%
- 2) 40%-50%
- 3) 20%-30%
- 4) 10%
Answer: 1)
Explanation: Depending upon the operation temperature the heat efficiency of a rotary dryer is 20-80%.
8. Which dryer is suitable for heat sensitive materials?
- 1) Indirect heat continuous dryer
- 2) Conical vacuum dryer
- 3) Agitated pan dryers
- 4) Jacketed-shelf dryer
Answer: 4)
Explanation: Jacketed-shelf dryer is suitable for heat sensitive and oxidizable materials.
9. Which dryer is used for drying powders and dyes?
- 1) Indirect heat continuous dryer
- 2) Conical vacuum dryer
- 3) Agitated pan dryers
- 4) Jacketed-shelf dryer
Answer: 2)
Explanation: Conical vacuum dryer is used to dry powders and dyes and pigments.
10. How does the heat transfer occurs in the indirect-heat continuous dryers?
- 1) Circulation
- 2) Radiation
- 3) Convection
- 4) Conduction
Answer: 4)
Explanation: In indirect-heat continuous dryers, heat transfer to the wet material occurs by conduction through the wall of the dryer.
