In case of a vertical tube evaporator, with increase in the liquor level,
the
(A) Capacity of the evaporator is decreased
(B) Capacity of the evaporator is increased
(C) True temperature drop increases
(D) Both (B) and (C)
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 : In case of a vertical tube evaporator, with increase in the liquor level, the __________ is increased. (A) Velocity of circulation (B) Liquor-film co-efficient (C) Both (A) and (B) (D) Neither (A) and (B)
Last Answer : (D) Neither (A) and (B)
Description : In case of vertical tube evaporator, with increase in liquor level, the overall heat transfer co-efficient (A) Increases (B) Decreases (C) Is not affected (D) May increase or decrease; depends on the feed
Last Answer : (B) Decreases
Description : Reason for operating an evaporator in multiple effects is to secure (A) Increased steam economy (B) Decreased steam consumption (C) Both (A) and (B) (D) Increased capacity
Last Answer : (C) Both (A) and (B)
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 : For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in (A) Increased economy (B) Decreased economy (C) Lower capacity (D) No effect on economy
Last Answer : (A) Increased economy
Description : Steam is routed through the tube in case of a __________ evaporator. (A) Basket type (B) Horizontal tube (C) Short tube vertical (D) Long tube vertica
Last Answer : (B) Horizontal tube
Description : Pick out the wrong statement. (A) Bubble size increases with the dynamic viscosity of the liquid in case of nucleate pool boiling (B) Thermal conductivity of a dry material is more than ... in kg/hr in an evaporator (D) Vaporisation of organic substances in evaporator mostly causes foam formation
Last Answer : (B) Thermal conductivity of a dry material is more than that of the damp material
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)
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 : Economy of a multiple effect evaporator is not influenced much by the (A) Boiling point elevations (B) Temperature of the feed (C) Rate of heat transfer (D) Ratio of the weight of the thin liquor to thick liquor
Last Answer : (A) Boiling point elevations
Description : Which of the following is used for the concentration of rubber latex? (A) Agitated film evaporator (B) Long tube vertical evaporator (C) Short tube evaporator (D) Calandria
Last Answer : (A) Agitated film evaporator
Description : Which is the most suitable for the concert-ration of highly concentrated solution? (A) Open pan evaporation (B) Long tube vertical evaporator (C) Agitated film evaporator (D) None of these
Last Answer : (A) Open pan evaporation
Description : Which is the most suitable for the concentration of foamy & frothy liquors? (A) Agitated film evaporator (B) Long tube vertical evaporator (C) Open pan evaporator (D) None of these
Last Answer : (B) Long tube vertical evaporator
Description : A __________ evaporator employs an annular downtake. (A) Basket type (B) Horizontal (C) Long tube vertical (D) None of these
Last Answer : (A) Basket type
Description : Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator? (A) Long vertical evaporator (B) Horizontal tube evaporator (C) Agitated film evaporator (D) Calandria vertical tube evaporator
Last Answer : (C) Agitated film evaporator
Description : Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a ... recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators
Last Answer : (D) Heat sensitive materials should be concentrated in high pressure evaporators
Description : Black liquor generated during paper manufacture is concentrated in a (A) Single effect evaporator (B) Single effect evaporator followed by a crystalliser (C) Multiple effect evaporator (D) Multiple effect evaporators followed by a crystalliser
Last Answer : (C) Multiple effect evaporator
Description : Are there any alternatives to scraping a shell and tube if a capacity increase will make the pressure drop across the exchanger too large?
Last Answer : When an increase in capacity will cause excessive pressure drop, you may not have to junk the heat exchangers. A relatively inexpensive alteration is to reduce the number of tube passes. ... the exchangers in parallel or using lowfins or other special tubing. Source: Gulley Computer Associates
Description : Due to circumferential action of the spiral in a spirally reinforced column (A) Capacity of column is decreased (B) Ductility of column reduces (C) Capacity of column is decreased but ductility of column increases (D) Both the capacity of column and ductility of column increase
Last Answer : Answer: Option D
Description : Intermittent tube cleaning is possible to be done in case of a __________ evaporator. (A) Basket type (B) Horizontal tube (C) Calandria (D) None of these
Description : Steam consumption in kg/hr in case of an evaporator is given by (where, C & E are capacity the economy of the evaporator respectively). (A) C/E (B) E/C (C) CE (D) 1/CE
Last Answer : (A) C/E
Description : The actual temperature drop across the heating surface in an evaporator depends on the (A) Feed (B) Depth of liquid over heating surface (C) Pressure difference between steam chest and vapour space (D) All (A), (B) and (C)
Last Answer : (D) All (A), (B) and (C)
Description : The actual temperature drop across the heating surface of an evaporator depends on the (A) Liquid depth over the heating surface (B) Solution being evaporated (C) Pressure difference between the steam chest and the vapor space above the boiling liquid (D) All (A), (B) and (C)
Description : For absorbers, high pressure drop results in (A) Increased efficiency (B) Decreased efficiency (C) High operating cost (D) Better gas liquid contact
Last Answer : (C) High operating cost
Description : Which of the following statements is true concerning a stepdown transformer in an operating AC power circuit? A. Voltage and current will both be increased. B. Voltage and current will both be decreased C. Voltage decreases as current increases. D. Voltage increases as current decreases.
Last Answer : Answer: C
Description : For the same heat load and mass flow rate in the tube side of a shell and tube heat exchanger, one may use multipass on the tube side, because it (A) Decreases the pressure drop (B) ... the outlet temperature of cooling medium (C) Increases the overall heat transfer coefficient (D) None of these
Last Answer : (C) Increases the overall heat transfer coefficient
Description : In a multiple effect evaporator, the effect of boiling point elevation is to (A) Reduce the capacity (B) Reduce the economy (C) Increase the economy (D) None of these
Last Answer : (A) Reduce the capacity
Description : In case of a multipass shell and tube heat exchanger, the temperature drop in the fluid (A) Is inversely proportional to the resistance across which the drop occurs (B) And the wall are proportional to individual resistances (C) And the wall is not related (D) None of these
Last Answer : (B) And the wall are proportional to individual resistances
Description : Pick out the wrong statement. (A) Economy of a multiple effect evaporator is not influenced by the boiling point elevation (B) Two identical cubes of iron and copper will have the same heat ... in the field of refrigeration (D) Finned tube heat exchangers are suitable for heating air by steam
Last Answer : (B) Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature
Description : During drying of a solid, the critical moisture content increases with (A) Decreased drying rate (B) Increased thickness of the solid (C) Increased drying rate (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator. (A) Increases (B) Decreases (C) Remain constant (D) May increase or decrease, depends on the vacuum
Last Answer : (A) Increases
Description : Pick out the wrong statement. (A) The value of hydrostatic head increases with increase in vacuum in the effect in a multiple effect evaporator system (B) Entering velocity of the liquid in ... a multiple effect evaporation system, the number of effects is limited by the total boiling point rise
Last Answer : (C) Duhring's plot is used for calculating the concentration of solution
Description : The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the (A) Solution has ... B) Evaporators operate under vacuum (C) Evaporators operate at atmospheric pressure (D) None of these
Last Answer : (A) Solution has an elevation of boiling point
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 : Tubes are held between top and bottom tube sheets in Calandria type evaporator by keeping (A) Both the tube sheets fixed (B) Both the tube sheets floating (C) The top tube sheet floating and bottom tube sheet fixed (D) The top tube sheet fixed and the bottom tube-sheet floating
Last Answer : (A) Both the tube sheets fixed
Description : In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate. (A) Increases (B) Decreases (C) Does not affect (D) May increase or decrease, depends on the type of baffle
Description : Which of the following parameters is increased by use of finned tube in a multipass shell and tube heat exchanger? (A) Tube side pressure drop and the heat transfer rate (B) Convective heat transfer co-efficient (C) Effective tube surface area for convective heat transfer (D) All (A) (B) and (C)
Last Answer : (D) All (A) (B) and (C)
Description : Due to Circumferential action of the spiral reinforcement in a column [ A ] Capacity of column is decreased but ductility of column increases [ B ] Both the capacity of column an ductility of column increases [ C ] Capacity of column increases [ D ] Ductility of the column reduces
Last Answer : [ B ] Both the capacity of column an ductility of column increases
Description : A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides (A) Higher economy (B) Lower capacity (C) Both (A) & (B) (D) Lower economy
Last Answer : (A) Higher economy
Description : Most conducting materials such as copper, aluminum, iron, nickel, and tungsten _____________. A. increase in resistance with increased temperature B. increase in resistance with decreased ... C. decrease in resistance with increased temperature D. increase in conductance with increased temperature
Last Answer : Answer: A
Description : Evaporator tubes are generally (A) Horizontal (B) Vertical (C) Inclined (D) Random
Last Answer : (B) Vertical
Description : An increased serum ‘Iron’ and decreased ‘Fe’ binding capacity are found in (A) Fe-deficiency anaemia (B) Sideroblastic anaemia (C) Thalassaemia (D) Anaemia of chromic disorders
Last Answer : Answer : B
Description : An increased serum iron and decreased iron binding capacity is found in (A) Fe deficiency anemia (B) Sideroblastic anemia (C) Folate deficiency anemia (D) Sickle cell anemia
Description : Pick out the wrong statement. (A) The controlling resistance in case of heating of air by condensing steam is in the air film (B) The log mean temperature difference (LMTD) for ... a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature
Last Answer : (C) In case of a 1 - 2 shell and tube heat exchanger, the LMTD correction factor value increases sharply, when a temperature cross occurs
Description : Pick out the wrong statement. (A) Heat transfer by radiation cannot occur across an absolute volume (B) In case of a shell and tube heat exchanger, the pressure drop through the shell is ... The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same
Last Answer : (A) Heat transfer by radiation cannot occur across an absolute volume
Description : The suitable evaporator for concentration of foaming liquids is a __________ evaporator. (A) Long tube (B) Short tube (C) Vacuum (D) Falling film
Last Answer : (A) Long tube
Description : Fruit juice (a heat sensitive material) can be concentrated in a __________ evaporator. (A) Long tube (B) Falling film (C) High pressure (D) None of these
Last Answer : (B) Falling film
Description : Pick out the wrong statement. (A) 'Solvates' are chemical compounds formed by solute with their solvents. When water is the solvent, then it is called a 'hydrate' (B) In heat exchanger ... vertical evaporators, area of central downtake is about 50 to 100% of the total tube cross-sectional area
Last Answer : (C) Heat transfer co-efficient during nucleate boiling is not influenced by the agitation imparted
Description : An increase in the NH3 /CO2 ratio in urea manufacture results in (A) Increased degree of conversion of CO2 to urea (B) Decreased degree of conversion of NH3 to urea (C) Decreased yield of urea (D) Decreased specific volume of molten mass
Last Answer : (A) Increased degree of conversion of CO2 to urea