200 kg of solids (on dry basis) is subjected to a drying process for a period of 5000 seconds. The drying occurs in the constant rate period with the drying rate as, Nc = 0.5 × 10-3 kg/m2.s. The initial moisture content of the solid is 0.2 kg moisture/kg dry solid. The interfacial area available for drying is 4 m2/1000 kg of dry solid. The moisture content at the end of the drying period is (in kg moisture/kg dry solid)?

Related Mcqs:

1. In a laboratory test run, the rate of drying was found to be 0.5 x 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is______________________?

   A. 2000
   B. 4000
   C. 5000
   D. 6000

2. 1000 kg of wet solids are to be dried from 60% to 20% moisture (by weight). The mass of moisture removed in kg is__________________?

   A. 520
   B. 200
   C. 400
   D. 500

3. A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?

   A. t = 283 s
   B. t = 356 s
   C. t = 400 s
   D. t = 800 s

4. Which of the following is the most controlling factor for the rate of bubble detachment from the hot solid surface ?

   A. Liquid density
   B. Liquid viscosity
   C. Hot surface temperature
   D. Interfacial tension

5. A multiple effect evaporator has a capacity to process 4000 kg of solid caustic soda per day, when it is concentrating from 10% to 25% solids. The water evaporated in kg per day is__________________?

   A. 6000
   B. 24000
   C. 60000
   D. 48000

6. A process stream of dilute aqueous solution flowing at the rate of10 Kg.s-1 is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s-1. A 1 – 1 shell and tube heat exchanger is available. The best arrangement is_______________?

   A. Counter flow with process stream on shell side
   B. Counter flow with process stream on tube side
   C. Parallel flow with process stream on shell side
   D. Parallel flow with process stream on tube side

7. Condensing film co-efficient for steam on horizontal tubes ranges from 5000 to 15000 Kcal/hr.m2.°C. Condensation of vapor is carried out inside the tube in a shell and tube heat exchanger, when the_________________?

   A. Higher condensing film co-efficient is desired
   B. Condensate is corrosive in nature
   C. Lower pressure drop through the exchanger is desired
   D. Temperature of the incoming vapor is very high

8. Prandtl number for most of dry gases is about________________?

   A. 0.001
   B. 0.72
   C. 70
   D. 150

9. A metal wire of 0.01 m dia and thermal conductivity 200 W/m.K is exposed to a fluid stream with a convective heat transfer coefficient of 100 W/m2.K. The Biot number is ______________?

   A. 5.6
   B. 0.025
   C. 3.5
   D. 0.0035

10. Solid angle subtended by the finite surface at the radiating element is_________________?

    A. Called the view factor
    B. Called the angle of vision
    C. Proportional to the square of the distance between surfaces
    D. Expressed in terms of radians