- (A) Flights (located in the inside shell of rotary dryer) lift the material being dried and shower it down through the current of hot air/gases. It extends from the wall to a distance which is about 8-12% of the inside diameter of shell
- (B) Hold up of a rotary drier is defined as the fraction of the dryer volume occupied by the solid at any instant. The best performance for rotary drier is obtained, when the hold up is in the range of 0.05 to 0.15
- (C) Rotary dryer is suitable for drying sticky material
- (D) Recommended peripheral speed of a rotary drier is in the range of 10 to 30 metres/minute
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- (A) With decrease in feed temperature, the number of plates required for binary distillation decreases for a given ‘L/V’ ratio
- (B) The extraction per unit of total height for a short packed column is more effective than for a tall column, in case of liquid-liquid extraction
- (C) Natural draft cooling towers are made of ferroconcrete and its cross-section is wider at the bottom
- (D) Vander wall adsorption is also called chemisorption
- (A) For identical gas flow rates, less pressure drop occurs through a plate tower than through a packed tower
- (B) Plate column can handle greater liquid loads without flooding than packed column, but the liquid hold up is more in the case of plate column
- (C) For the same duty, plate columns weigh less than packed columns
- (D) All
- (A) Fine solids cannot be leached in a Pachuca tank
- (B) Door classifier can be used for leaching of coarse solids
- (C) Vegetable seeds can be leached in either of Bollman extractor, Rotocel or Kennedy extractor
- (D) Very high temperature is not needed for the leaching of sugar beet
- (A) Bound moisture is removed during constant rate drying period
- (B) Free moisture is removed during falling rate drying period
- (C) The sum of free moisture and equilibrium moisture in a solid is called the critical moisture
- (D) The driving force for mass transfer in a wet solid is its free moisture content
- (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the possibility of tower wall collapse
- (B) Packed towers are preferred over plate towers for handling corrosive and foamy liquids
- (C) Diameter of randomly packed tower is normally more than 1.2 metres
- (D) Due to uneven supply and improper distribution of liquid, problem of channelling, loading & flooding is generally encountered in packed towers
- (A) Different solids have different equilibrium moisture curves
- (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of theoretical plate calculation for distillation column
- (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column
- (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature
- (A) Increases
- (B) Decreases
- (C) Remains unchanged
- (D) Depends on relative volatility
- (A) Separation of uranium oxide from its ore by H2SO4 in a Pachuca tank
- (B) Separation of sugar from sugar beet by hot water
- (C) Dissolution of tannin out of tree barks by water
- (D) Recovery of vegetable oils from seeds
- (A) Increases
- (B) Decreases
- (C) Remains same
- (D) Either
