or the same heat transfer area and the terminal conditions, the ratio
of the capacities of a single effect evaporator to a triple effect evaporator is
(A) 3
(B) 0.33
(C) 1
(D) 1.33
Description : A multiple effect evaporator as compared to a single effect evaporator of the same capacity has (A) Lower heat transfer area (B) Lower steam economy (C) Higher steam economy (D) Higher solute concentration in the product
Last Answer : (C) Higher steam economy
Description : . A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of ... in a single effect is much lower than that in any effect in a multi-effect system
Last Answer : (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect
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 : Two footings, one circular and the other square, are founded on the surface of a purely cohesionless soil. The diameter of the circular footing is the same as that of the side of the square footing. The ratio between their ultimate bearing capacities will be : (a) 1.0 (b) 1.3 (c) 1.33 (d) 0.75
Last Answer : (d) 0.75
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 : Steam economy in case of a triple effect evaporator will be (A) 1 (B) < 1 (C) > 1 (D) Between 0 and 1
Last Answer : (C) > 1
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 : Optimum number of effects in a multiple effect evaporator is decided by the (A) Cost benefit analysis (B) Floor area availability (C) Terminal parameters (D) Evaporation capacity required
Last Answer : (A) Cost benefit analysis
Description : A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer coefficient for air will vary in the ratio of (A) 2 (B) 2 0.8 (C) 2 0.2 (D) 2 0.5
Last Answer : (B) 2 0.8
Description : Economy of a multiple effect evaporator depends upon the (A) Heat balance consideration (B) Rate of heat transfer (C) Both (A) and (B) (D) Neither (A) nor (B
Last Answer : (A) Heat balance consideration
Description : LMTD for evaporators & condensers for a given terminal parameters & set of conditions for counter-flow is equal to that for parallel flow. In such heat exchangers, with one of the fluids condensing or evaporating, the surface ... Parallel (B) Mixed (C) Counter flow (D) Same in either 'a', b' or 'c'
Last Answer : (D) Same in either 'a', b' or 'c'
Description : The refrigeration effect in a dry evaporator compared to flooded evaporator in a similar plant is (a) same (b) more (c) less (d) more or less depending on ambient conditions
Last Answer : Ans: c
Description : Evaporation of 1kg of water from a solution in a single effect evaporator requires about __________ kg of steam. (A) 0.4 - 0.6 (B) 1-1.3 (C) 1.8-2 (D) 2 - 2.4
Last Answer : (B) 1-1.3
Description : What is the steam economy in case of a single effect evaporator system? (A) 1 (B) > 1 (C) < 1 (D) 0.1
Last Answer : (C) < 1
Description : In a forward feed multiple effect evaporator unit (A) Viscosity of liquid is highest in first effect (B) Transfer from effect to effect is done by pumps (C) No pump is required to withdraw the product from the last effect (D) None of these
Last Answer : (D) None of these
Description : Steam side heat transfer co-efficient in an evaporator is in the range of __________ kcal/hr.m2°C. (A) 10-50 (B) 100-500 (C) 1000-1500 (D) 5000-15000
Last Answer : (D) 5000-15000
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 : In case of evaporators, liquid entrainment results primarily due to (A) High vacuum in the evaporator (B) High evaporation rate (C) Foaming of the solution (D) High heat transfer rate
Last Answer : (C) Foaming of the solution
Description : Adiabatic bulk modulus is equal to: A. Υ × P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure B. Pressure C. The ratio of the specific heat capacities of the gas D. Υ ⁄ P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure
Last Answer : Υ × P; where Υ: the ratio of the specific heat capacities of the gas, P: pressur
Description : Isothermal bulk modulus is equal to A. Υ × P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure B. Pressure C. The ratio of the specific heat capacities of the gas D. Υ ⁄ P; where Υ: the ratio of the specific heat capacities of the gas, P: pressure
Last Answer : Pressure
Description : The reaction A → B is conducted in an adiabatic plug flow reactor (PFR). Pure A at a concentration of 2 kmol/m3 is fed to the reactor at the rate of 0.01 m3 /s and at a temperature of 500 K. If the exit ... /kmole. K (may be assumed to be independent of temperature)) (A) 400 (B) 500 (C) 600 (D) 1000
Last Answer : (C) 600
Description : In a single effect evaporator, the economy is (A) 1 (B) < 1 (C) > 1 (D) None of these
Last Answer : (B) < 1
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 : Vacuum is generally maintained in the vapour space of an evaporator mainly to (A) Get economical temperature difference by using moderate pressure steam (B) Facilitate forward ... (C) Concentrate heat sensitive materials (D) Achieve very high concentration of the final product
Last Answer : (A) Get economical temperature difference by using moderate pressure steam
Description : Small scale evaporation is done in a (A) Heat exchanger (B) Condenser (C) Multiple effect evaporator (D) Steam jacketed kettle
Last Answer : (D) Steam jacketed kettle
Description : Choose the wrong statement (a) Temperature of medium being cooled must be below that of the evaporator (b) Refrigerant leaves the condenser as liquid (c) All solar thermally operated absorption systems are capable only of intermittent operation (d) frost on evaporator reduces heat transfer
Last Answer : Ans: a
Description : Formation of frost on evaporator in refrigerator (a) results in loss of heat due to poor heat transfer (b) increases heat transfer rate (c) decreases compressor power. (d) can be avoided by proper design
Description : . If all the conditions and dimensions are same, then the ratio of velocity through the tubes of a double pass heat exchanger to that through the single pass heat exchanger is (A) 1 (B) 2 (C) 1/2 (D) 4
Last Answer : (B) 2
Description : If the molar heat capacities (Cp or Cv) of the reactants and products of a chemical reaction are identical, then, with the increase in temperature, the heat of reaction will (A) Increase (B) Decrease (C) Remain unaltered (D) Increase or decrease; depends on the particular reaction
Last Answer : (C) Remain unaltered
Description : With increase in temperature, the atomic heat capacities of all solid elements (A) Increases (B) Decreases (C) Remains unchanged (D) Decreases linearly
Last Answer : (A) Increases
Description : The heat capacities for the ideal gas state depend upon the (A) Pressure (B) Temperature (C) Both (A) & (B) (D) Neither (A) nor (B)
Last Answer : (B) Temperature
Description : Parallel straight line pattern of temperature distribution for both hot and cold fluids is observed in case of heat exchanger of the type (A) Parallel flow with equal heat capacities (B) Counter ... (C) Counter flow with unequal heat capacities (D) Parallel flow with unequal heat capacities
Last Answer : (B) Counter flow with equal heat capacities
Description : In a forward feed multiple effect evaporator, the pressure is (A) Highest in last effect (B) Lowest in last effect (C) Same in all effects (D) Dependent on the number of effects
Last Answer : (B) Lowest in last effect
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 : You wish to purchase a dental X ray machine and have the choice between 60kVp and 70kVp machines. With single change from 60kVp to 70kVp what would the approximate affects on exposure time?CHECK A. No effect B. Half the time C. Double D. Quarter E. Triple the time
Last Answer : B. Half the time
Description : A,b and C can do a piece of work in 3,4 and 6 days respectively. The ratio of their work capacities is …………..
Last Answer : A,b and C can do a piece of work in 3,4 and 6 days respectively. The ratio of their work capacities is …………..
Description : Two transformers of identical voltages but different capacities are operated in parallel, for satisfactory load sharing: a) Impedances should be equal b) Per unit impedance must be equal c) per unit impedance and X/R ratio must be equal d) Impedance and X/R ratio must be equal
Last Answer : Ans: C
Description : A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter 'd'. For a fixed mass flow rate, the tube side heat transfer coefficient for turbulent flow conditions is proportional to (A) d 0.8 (B) d -0.2 (C) d -1 (D) d -1.8
Last Answer : (B) d -0.2
Description : For the same terminal conditions and valve size, the pressure drop in a fully opened globe valve as compared to that in a gate valve is (A) More (B) Less (C) Equal (D) Either (A) or (B); depends on the viscosity of the fluid
Last Answer : (A) More
Description : For the same terminal conditions and fitting size, the least friction lossis incurred in a/an (A) T-joint (B) Union (C) 45° elbow (D) 90°bend
Last Answer : (B) Union
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
Description : For turbulent mass transfer in pipes, the Sherwood number depends on the Reynolds number as (A) Re 0.33 (B) Re 0.53 (C) Re 0.83 (D) Re
Last Answer : (C) Re 0.83
Description : Tubes of multiple effect evaporator used for concentration of sugar cane juice are made of (A) Nickel (B) Copper (C) Stainless steel (D) Brass
Last Answer : (B) Copper
Description : Which of the following employs an accessory known as 'drift eliminator'? (A) Multiple effect evaporator (B) Mechanical draft cooling tower (C) Rotary dryer (D) Rotating disc contacto
Last Answer : (B) Mechanical draft cooling tower
Description : . In a backward feed multiple effect evaporator (A) Feed is introduced in the first effect (B) Feed flows from low pressure to high pressure (C) No pumps are required between successive effects (D) None of these
Last Answer : (B) Feed flows from low pressure to high pressure
Description : Economy of an evaporator is influenced by the (A) Steam pressure (B) Feed temperature (C) Number of effect (D) Both (B) & (C)
Last Answer : (D) Both (B) & (C)
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 : For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is (A) Forward (B) Backward (C) Parallel (D) None of these
Last Answer : (B) Backward
Description : 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
Last Answer : (B) 24000