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

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

by

1 Answer

Answer :

(A) Reduce the capacity


by

Related questions

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 content under the same conditions of temperature (C) Double pipe heat exchangers are mostly used in the field of refrigeration (D) Finned tube heat exchangers are suitable for heating air by steam

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

. 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 all the effects is -less than that in a single effect evaporator system (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect (C) Boiling point elevation in a single effect system is much higher than that in any effect in a multi-effect system (D) Heat transfer co-efficient in a single effect is much lower than that in any effect in a multi-effect system

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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

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 an elevation of boiling point (B) Evaporators operate under vacuum (C) Evaporators operate at atmospheric pressure (D) None of these

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Last Answer : (A) Solution has an elevation of boiling point

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

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Last Answer : (A) Boiling point elevations

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 shell and tube heat exchanger (C) Steam jet ejector is used for vapor compression in a thermal recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators

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Last Answer : (D) Heat sensitive materials should be concentrated in high pressure evaporators

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 the tubes of natural circulation evaporators is in the range of 0.3 to 0.9 metre/second (C) Duhring's plot is used for calculating the concentration of solution (D) In a multiple effect evaporation system, the number of effects is limited by the total boiling point rise

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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

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Last Answer : (A) Higher economy

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

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Last Answer : (C) Higher steam economy

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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

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Last Answer : (C) Both (A) and (B)

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

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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

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Last Answer : (B) 24000

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

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Last Answer : (A) Cost benefit analysis

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

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Last Answer : (A) Cost benefit analysis

Multiple effect evaporators ar used to (A) Increase the steam economy & decrease the capacity (B) Increase the steam economy & the capacity (C) Decrease the steam economy & the capacity (D) Decrease the steam economy & increase the capacity

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Last Answer : (B) Increase the steam economy & the capacity

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

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The number of kg vaporised per kg of steam fed to the evaporator is defined as (A) Capacity (B) Rate of evaporation (C) Economy (D) Rate of vaporisation

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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

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Kg of liquid evaporated per hour in an evaporator is defined as its (A) Capacity (B) Economy (C) Steam load (D) None of these

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Define capacity and economy of evaporator.

Description : Define capacity and economy of evaporator.

Last Answer : The capacity of an evaporator is defined as the number of kilogram of water evaporated per hour. The economy of an evaporator is defined as the number of kilogram of water evaporated per kilogram of steam fed to the evaporator.

Economy of an evaporator is influenced by the (A) Steam pressure (B) Feed temperature (C) Number of effect (D) Both (B) & (C)

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)

What is the steam economy in case of a single effect evaporator system? (A) 1 (B) > 1 (C) < 1 (D) 0.1

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Last Answer : (C) < 1

In a single effect evaporator, the economy is (A) 1 (B) < 1 (C) > 1 (D) None of these

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Last Answer : (B) < 1

Steam economy in case of a triple effect evaporator will be (A) 1(B) < 1 (C) > 1 (D) Between 0 and 1

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It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of vaporisation is 2100 kJ/kg and the specific heat of the solution is 4 kJ/kg.K. The rate at which the heat has to be supplied in (kJ/min) to the evaporator is (A) 3.06 × 10 5 (B) 6.12 × 10 5 (C) 7.24 × 10 5 (D) 9.08 × 10

Description : It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of ... 3.06 10 5 (B) 6.12 10 5 (C) 7.24 10 5 (D) 9.08 10

Last Answer : (A) 3.06 × 10

Tubes of multiple effect evaporator used for concentration of sugar cane juice are made of (A) Nickel (B) Copper (C) Stainless steel (D) Brass

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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

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Last Answer : (B) Mechanical draft cooling tower

. 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

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Last Answer : (B) Feed flows from low pressure to high pressure

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 feeding in multiple effect evaporation (C) Concentrate heat sensitive materials (D) Achieve very high concentration of the final product

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

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

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Last Answer : (B) Backward

Small scale evaporation is done in a (A) Heat exchanger (B) Condenser(C) Multiple effect evaporator(D) Steam jacketed kettle

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

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

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

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

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

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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

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

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

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Last Answer : (A) Increases

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 : 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)

Last Answer : (A) Capacity of the evaporator is decreased

Boiling point elevation of a solution of NaOH (A) Increases rapidly with temperature rise (B) Is almost independent of temperature (C) Is almost independent of pressure (D) Both (B) and (C)

Description : Boiling point elevation of a solution of NaOH (A) Increases rapidly with temperature rise (B) Is almost independent of temperature (C) Is almost independent of pressure (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Boiling point elevation of an ideal solution (A) Increases rapidly with temperature rise (B) Decreases rapidly with temperature rise (C) In independent of pressure (D) Both (B) and (C)

Description : Boiling point elevation of an ideal solution (A) Increases rapidly with temperature rise (B) Decreases rapidly with temperature rise (C) In independent of pressure (D) Both (B) and (C)

Last Answer : (A) Increases rapidly with temperature rise

. Boiling point elevation for a strong and concentrated solution is found by Duhring's rule, which states that at the same pressure, the boiling point of a solution is a linear function of the __________ of pure water. (A) Boiling point (B) Dynamic viscosity (C) Kinematic viscosity (D) Density

Description : . Boiling point elevation for a strong and concentrated solution is found by Duhring's rule, which states that at the same pressure, the boiling point of a solution is a linear function of the __________ of pure water. (A) Boiling point (B) Dynamic viscosity (C) Kinematic viscosity (D) Density

Last Answer : (A) Boiling point

Pick out the wrong statement. (A) Heat transfer from a hot body to cold body by the emission of heat waves is called radiation (B) Filmwise condensation takes place on non-wettable surfaces (C) The boiling point of a solution is affected by liquid head as well as boiling point elevation (D) None of these

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Last Answer : (B) Filmwise condensation takes place on non-wettable surfaces

Explain the type of multiple effect evaporator feed arrangement used for handling viscous liquid.

Description : Explain the type of multiple effect evaporator feed arrangement used for handling viscous liquid.

Last Answer : Backward feed arrangement  If the liquid is very viscous, then we have to adopt backward feed arrangement. In this arrangement, the feed solution and vapour flow is in opposite direction. Fresh feed is ... Not very common as it need pump. At low values of feed temperature higher economy.

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)

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What is the boiling point of water at an elevation of 1.55 and times104 ft?

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Last Answer : The boiling point of water at this altitude is 84,2 oC.

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Description : The use of pressurized radiator cap is to a) Reduce evaporation loss b) Increase engine operating temperature c) Increase boiling point of water d) Reduce heat losses

Last Answer : ans c

Use of multiple notches in a V shaped flat plate will a) Reduce the stress concentration b) Increase the stress concentration c) No effect d) Cannot be determined

Description : Use of multiple notches in a V shaped flat plate will a) Reduce the stress concentration b) Increase the stress concentration c) No effect d) Cannot be determined

Last Answer : a) Reduce the stress concentration

In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to (a) collect liquid refrigerant and prevent it from going to compressor (b) detect liquid in vapour (c) superheat the vapour (d) increase refrigeration effect

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Last Answer : Ans: a

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Description : Multiple effect evaporation accounts for (A) Steam economy (B) Lower operating costs (C) Investment economy (D) None of these

Last Answer : (A) Steam economy

Evaporation by thermo compression results in the (A) Saving of steam (B) Realisation of multiple effect economy in a single effect (C) Both (A) and (B) (D) None of these

Description : Evaporation by thermo compression results in the (A) Saving of steam (B) Realisation of multiple effect economy in a single effect (C) Both (A) and (B) (D) None of these

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