Heat and Mass Transfer Flashcards
Evaporation is also sometimes called as
a. thermal compression
b. liquid compression
c. water distillation
d. vapor compression
c
The concentration of glycerin from a water solution by the application of heat is
a. distillation
b. evaporation
c. crystallization
d. reverse osmosis
b
The total amount of evaporation an evaporator is capable of producing per unit of time.
a. economy
b. capacity
c. steam consumption
d. fouling factors
b
When the pressure of the chamber is decreased, the boiling point of the solution inside the chamber will
a. increase
b. remain the same
c. decrease
d. increase or decrease
c
A heat transfer device that is normally used to liquefy vapors is
a. evaporator
b. condenser
c. reboiler
d. humidifier
b
The temperature driving force in an evaporator is determined as the difference between the condensing steam temperature and
a. condenser temperature
b.boiling point of the solution
c. boiling point of the solvent
steam
d. BPR of the solution
b. Ts - T
In a country where capital is scarce and energy cost is low) which is appropriate to install?
a. multiple effect evaporator
b. single effect evaporator
b
The fresh feed enters at the coldest effect.
a. feed-forward
b. parallel-feed
c. feed-backward
d. none of these
c
In commercial practice, the areas in all effects for a multiple effect evaporator are
a. greater
b. constant
c. lesser
d. both a and b
b.
areas are assumed equal in evaporation calculations
A multiple effect evaporator _______ the steam cost
a. increases
c. decreases
b. keep the same
d. double
c bc vapor from effect 1 is used as steam in effect 2
______ of the vapor is recovered and reuse in the multiple effect
a. heat transfer
b. latent heat
c. specific heat
d. sensible heat
b
It is the deposition and growth on body walls, and specially on heating surfaces, of a material undergoing an irreversible chemical reaction in the evaporator.
a. salting
b. fouling
c. scaling
d. boiling
c
It is the formation of deposits other than salt or scale and maybe due to corrosion.
a. salting
b. fouling
c. scaling
d. boiling
b
The growth on body and heating surface walls of a materal having a solubility that increases in temperature
a. salting
b. fouling
c. scaling
d. boiling
a
