Chemical Engineering Mcqs

Leidenfrost point is a term concerned with the____________________?

• (A)  Condensation of the saturated vapor on a cold surface
• (B)  Concentration of a corrosive solution by evaporation
• (C)  Heat transfer between two highly viscous liquids
• (D)  Boiling of a liquid on a hot surface

Answer

Submitted By :Ali Uppal

Which of the following is not used as a medium for high temperature heating ?

• (A)  Dowtherm
• (B)  Mercury
• (C)  Liquid metal (e.g. molten sodium)
• (D)  Fused salts (
• (E)  g., an eutectic mixture of 53% KNO3, 40% NaNO2and 7% NaNO3)

Answer

Submitted By :Ali Uppal

The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by ______________ times, when the number of tube passes is increased to 8?

• (A)  20.8
• (B)  40.8
• (C)  40.4
• (D)  20.4

Answer

Submitted By :Ali Uppal

In regenerative air preheater (as practised in heating of coke ovens), the heat is transferred_________________?

• (A)  Through a metallic wall
• (B)  By direct contact of hot flue gas with air
• (C)  By heating an intermediate material (like chequor bricks) and then heating the air from this hot material
• (D)  None of these

Answer

Submitted By :Ali Uppal

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

Answer

Submitted By :Ali Uppal

The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe whose surface temperature remains constant is______________?

• (A)  1.66
• (B)  88.66
• (C)  3.66
• (D)  Dependent on NRe only

Answer

Submitted By :Ali Uppal

Which characteristic of a fluid is not important in deciding its route in a shell and tube heat exchanger ?

• (A)  Corrosiveness
• (B)  Fouling characteristic
• (C)  Viscosity
• (D)  None of these

Answer

Submitted By :Ali Uppal

Crystal size in a continuous crystalliser depends upon the___________________?

• (A)  Rate of heat transfer
• (B)  Degree of turbulence
• (C)  Degree of super-saturation
• (D)  All

Answer

Submitted By :Ali Uppal

Boiling of milk in an open vessel is an example of ______________ boiling?

• (A)  Film
• (B)  Sub-cooled
• (C)  Saturated nucleate
• (D)  None of these

Answer

Submitted By :Ali Uppal

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

Answer

Submitted By :Ali Uppal