Tower diameter may be decreased by
(A) Using higher reflux ratio
(B) Use of increased tray spacing
(C) Increasing the liquid flow rate
(D) Increasing the vapour flow rate
Description : When a multistage tray tower uses a minimum reflux ratio, it implies (A) Infinite trays and maximum reboiler heat load (B) Infinite trays and minimum reboiler heat load (C) Minimum trays and minimum reboiler heat load (D) Minimum trays and maximum reboiler heat load
Last Answer : (A) Infinite trays and maximum reboiler heat load
Description : The feed to fractionating column is changed from saturated vapour to saturated liquid. If the separation and reflux ratio remains unchanged, the number of ideal stages will (A) Increase (B) Decrease (C) Remain same (D) Depend on saturated boiling point; may increase or decrease
Last Answer : (A) Increase
Description : In case of binary distillation, increasing the reflux ratio above optimum does not result in the increase of (A) Area between operating line and 45° diagonal x-y diagram (B) Condenser and reboiler surfaces (C) Tower cross-section (D) None of these
Last Answer : (A) Area between operating line and 45° diagonal x-y diagram
Description : As the reflux ratio in a distillation column is increased from the minimum, the (A) Slope of the operating line in stripping section decreases (B) Number of plates decreases very slowly first ... decreases and then increases (D) Liquid flow increases while the vapor flow decreases for a system
Last Answer : (C) Total cost first decreases and then increases
Description : For a distillation column operating at minimum reflux, the (A) Concentration of liquid and vapour leaving a plate will be same (B) Reflux ratio will be maximum (C) Number of plates required will be maximum
Last Answer : (C) Number of plates required will be maximum
Description : In order to achieve economy, the spacing of stirrups at mid span section---------- compared to that of support section [ A ] May be decreased [ B ] May be increased [ C ] Must be kept equal [ D ] None of the above.
Last Answer : [ B ] May be increased
Description : An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are ... (D) More number of trays are required and the residue composition is more dilute in methano
Last Answer : (A) Less number of trays are required
Description : Tray spacing in a distillation column of dia 10-12 ft. used in petroleum refinery may be around __________ inches. (A) 5 (B) 30 (C) 60 (D) 100
Last Answer : (B) 30
Description : Out of the following gas-liquid contacting devices, for a given set of operating conditions, gas pressure drop is the least in __________ tower. (A) Wetted wall (B) Bubble cap (C) Perforated tray (D) Packed
Last Answer : (A) Wetted wall
Description : Which of the following gas-liquid contacting devices incurs the least pressure drop for a particular duty? (A) Grid tray tower (B) Perforated tray tower (C) Wetted wall tower (D) Bubble cap tower
Last Answer : (D) Bubble cap tower
Description : Back-trapping in a distillation column (A) Increases tray efficiency (B) Decreases tray efficiency (C) Reduces pressure drop (D) Is desirable, as it provides improved vapour-liquid contact
Last Answer : (B) Decreases tray efficiency
Description : An example of unsteady non uniform flow is the flow of liquid under pressure through a (A) Tapering pipe at constant flow rate (B) Tapering pipe at either decreasing or increasing flow rate (C) Long pipeline of constant diameter (D) None of these
Last Answer : (B) Tapering pipe at either decreasing or increasing flow rate
Description : Pick out the wrong statement. (A) When the concentration difference for the mass transfer becomes zero at the bottom of the gas absorption tower, then the upper end of the operating line touches the ... fixed gas flow rate, the slope of the operating line decreases, in case of gas absorption process
Last Answer : (C) The operating line lies above the equilibrium curve in case of a gas desorber
Description : Pick out the wrong statement about cavitation. (A) Sudden reduction of pressure in a fluid flow system caused by flow separation, vortex formation or abrupt closing of valve leads to cavitation ... (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades
Last Answer : (D) Large scale cavitation cannot damage pipeline, restrict fluid flow and damage steam turbine blades
Description : Spacing of stirrups in a rectangular beam, is (A) Kept constant throughout the length (B) Decreased towards the centre of the beam (C) Increased at the ends (D) Increased at the centre of the beam
Last Answer : Answer: Option D
Description : The centre to centre spacing of vertical stirrups, in a rectangular beam, is (a) Increased towards the centre of the span of the beam (b) Decreased towards the centre of the span of the beam. (c) Increased at the ends. (d) None of these
Last Answer : (a) Increased towards the centre of the span of the beam
Description : While increasing the forward speed of the combine harvester speed of reel should be a) Increased in same ratio b) Decreased in same ratio c) No changes d) Doubled Ans. a
Last Answer : ans a
Description : Pick out the wrong statement. (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 ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature
Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column
Description : Pick out the correct statement. (A) The slope of the stripping line is always less than unity (B) For a given separation in a binary distillation column, with increase in reflux ratio ( ... (D) Kremser-Brown-Souder's equation is used to calculate the efficiency of a plate tower
Last Answer : C) In Ponchon-Savarit method of no. of theoretical plate determination, the stripping and rectifying operating lines are vertical at total reflux
Description : Can the efficiency of a plate in the distillation tower be greater than 100%? (A) Yes (B) Normally not; but is possible if infinite number of plates are put (C) Never (D) Yes; if the reflux ratio is maximum
Last Answer : (C) Never
Description : Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in (A) Increased COP (B) Same COP (C) Decreased COP (D) Increased or decreased COP; depending upon the type of refrigerant
Last Answer : (A) Increased COP
Description : Cavitation will begin when (A) The pressure at any location reaches an absolute pressure equal to the saturated vapour pressure of the liquid (B) Pressure becomes more than critical pressure (C) Flow is increased (D) Pressure is increased
Last Answer : Answer: Option A
Description : For the same system, if the same liquid used in an absorber is decreased, the tower height will (A) Increase (B) Decrease (C) Remain unaffected (D) Decrease or increase; depends on the type of liquid
Description : With increase in temperature, the leaching rate increases because of the (A) Increased diffusivity (B) Decreased viscosity of liquid (C) Both (A) and (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) and (B)
Description : With increase in temperature, the leaching rate increases due to (A) Decreased liquid viscosity (B) Increased diffusivity (C) Both (A) and (B) (D) Neither (A) nor (B)
Description : The sensitivity of a bubble tube can be increased by (A) Increasing the diameter of the tube (B) Decreasing the length of bubble (C) Increasing the viscosity of liquid (D) Decreasing the radius of curvature of tube
Last Answer : (A) Increasing the diameter of the tube
Description : The cooling effect in a cooling tower cannot be increased by (A) Increasing the air velocity over the wet surfaces (B) Reducing the humidity of entering air (C) Lowering the barometric pressure (D) None of these
Last Answer : (D) None of these
Description : The relative saturation of a partially saturated mixture of vapour and gas can be increased by __________ of the mixture. (A) Reducing the total pressure (B) Increasing the total pressure (C) Reducing the temperature (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : At the same gas flow rate, the pressure drop in a packed tower being irrigated with liquid __________ that in dry packed tower. (A) Is greater than (B) Is lower than (C) Is same as (D) Cannot be predicted as data are insufficient
Last Answer : (A) Is greater than
Description : Pick out the correct statement about the condensation. (A) Filmwise condensation gives a lower heat transfer rate than the dropwise condensation (B) Suitable coating or vapour additive is used to promote film ... place on it (D) Reynolds number of condensing liquid is based on its mass flow rate
Last Answer : (B) Suitable coating or vapour additive is used to promote film wise condensation
Description : Hydrogenation of oil is carried out in a/an __________ in Vanaspati manufacturing plant. (A) Agitated vessel (B) Sieve tray column (C) Bubble cap column (D) Packed tower
Last Answer : (A) Agitated vessel
Description : Second order consecutive irreversible reaction as shown in the bellow figure, were carried out in a constant volume isothermal batch reactor with different initial feed compositions. Reactor temperature was same in all the cases. In experiments ... constants (k1 /k2 )? (A) 1/4 (B) 1/2 (C) 2 (D) 4
Last Answer : (A) 1/4
Description : According to principle of diminishing marginal rate of substitution a. One commodity must be decreased while other is increased b. Commodity which is increased has higher marginal significance c. Commodity which is decreased ... .Both a and b are correct C.Both a and c are correct D.All are correct
Last Answer : C.Both a and c are correct
Description : Increasing the liquor level in the evaporator results in the (A) Decreased capacity (B) Increase in liquor film co-efficient (C) Decreased effect of hydrostatic head (D) Increased true temperature drop
Last Answer : (A) Decreased capacity
Description : Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater ... (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (C) Both (A) & (B)
Description : In a distillation operation, what is the effect of the temperature of the reflux stream (given below) on the condenser and reboiler loads? Reflux conditions: (i) Reflux stream is completely liquid ... D) Both condenser and reboiler loads are higher in case (ii) as compared to case (i)
Last Answer : (D) Both condenser and reboiler loads are higher in case (ii) as compared to case (i)
Description : As the reflux ratio decreases, the (A) Separation becomes more efficient (B) Number of plates increases (C) Column diameter increases (D) None of these
Last Answer : (B) Number of plates increases
Description : Which of the following medications used for the treatment of obesity prevents the absorption of triglycerides? a) Orlistat (Xenical) Orlistat (Xenical) prevents the absorption of triglycerides. Side effects of ... (Prozac) has not been approved by the FDA for use in the treatment of obesity.
Last Answer : a) Orlistat (Xenical) Orlistat (Xenical) prevents the absorption of triglycerides. Side effects of Xenical may include increased bowel movements, gas with oily discharge, decreased food absorption, decreased bile flow, and decreased absorption of some vitamins.
Description : Reynolds number of a fluid flowing in a circular pipe is 10,000. What will be the Reynolds number when the fluid velocity is decreased by 30% & the pipe diameter is increased by 30%? (A) 9,100 (B) 13,000 (C) 7,000 (D) 2,550
Last Answer : (A) 9,100
Description : The primary mechanism by which antidiuretic hormone reduces urine volume is: A. Decrease in glomerular filtration rate B. Decreased renal blood flow C. Decreased water permeability of descending limb of loop of Henle D. Increased water permeability of collecting duct cells
Last Answer : D. Increased water permeability of collecting duct cells
Description : For a fixed number of ideal stages in a distillation column, as the reflux ratio is increased, the difference in composition between the top and bottom product streams (A) Increases (B) Decreases (C) Remain unaffected (D) Passes through a maximum
Last Answer : (A) Increases
Description : As the reflux ratio, in a continuous counter-current extraction is increased, the number of stages (A) Increase (B) Decrease (C) Remain unchanged
Last Answer : (B) Decrease
Description : Pick out the wrong statement. (A) Packed towers are preferred for vacuum operation, because the pressure drop through the packing is less and they (packings) also lessen the ... of liquid, problem of channelling, loading & flooding is generally encountered in packed towers
Last Answer : (C) Diameter of randomly packed tower is normally more than 1.2 metres
Description : If the path of liquid across the plate is very long as in case of large diameter tower, Murphree efficiency can be __________ percent (A) 100 (B) > 100 (C) < 100 (D) None of these
Last Answer : (B) > 100
Description : In which system is Cooling of hot water is done on tray as step by? a) Mechanical draught cooling system b) Hyperbolic cooling tower c) Atmospheric cooling tower d) Wet cooling tower
Last Answer : Atmospheric cooling tower
Description : In which system is Cooling of hot water is done on tray as step by? a. Mechanical draught cooling system b. Hyperbolic cooling tower c. Atmospheric cooling tower d. Wet cooling tower
Description : . In which system is Cooling of hot water is done on tray as step by? a) Mechanical draught cooling system b) Hyperbolic cooling tower c) Atmospheric cooling tower d) Wet cooling tower
Description : The shock absorbing capacity of a bolt can be increased by (A) Increasing shank diameter (B) Making shank diameter equal to core diameter of threads (C) Using castle nut in place of ordinary hexagonal nut (D) Using a washer
Last Answer : (B) Making shank diameter equal to core diameter of threads
Description : Flat footed camels can walk easily in sandy deserts because - (1) pressure on the sand is decreased by increasing the area of the surface in contact (2) pressure on the sand is increased by ... in contact (4) pressure on the sand is increased by decreasing the area of the surface in contact
Last Answer : (1) pressure on the sand is decreased by increasing the area of the surface in contact Explanation: Camels have broad, flat, leathery pads with two toes on each foot. When the camel places its foot on ... the animal on loose sand in much the same way that a snowshoe helps a person walk on snow.
Description : Which of the following best explains why the melting points of saturated fats increase with increasing molecular weight? (a) decreased hydrogen bonding (b) increased hydrogen bonding (c) decreased intermolecular van der Waal’s interactions (d) increased intermolecular van der Waal’s interactions
Last Answer : increased intermolecular van der Waal’s interactions