BLRS 6008 - Electric Boilers (Chp 4)

Question 1

An immersion type of electric boiler:

A) Passes current through the water
B) Generates heat utilizing a bundle of heating elements
C) Uses pressure to directly regulate energy consumption
D) Does everything shown here
E) Depends on water level to regulate steam production

Answer 1

B) Generates heat utilizing a bundle of heating elements

Question 2

In an electrode type of electric boiler:

A) More steam is generated when the generating zone level drops
B) As generating zone water level decreases, current increases
C) Current decreases as pressure drops
D) Current increases as the generating zone level drops
E) Electrical current decreases as pressure goes up

Answer 2

E) Electrical current “decreases” as “pressure goes up”

Question 3

Electrode type boilers:

A) Require complex control systems
B) Self regulate steam pressure
C) Require microprocessor control
D) Require external resistance for control
E) Require electrodes to be totally immersed in water

Answer 3

B) Self regulate steam pressure

An electrode boiler (jet type) is a type of boiler that uses electricity flowing through streams of water to create steam.

Question 4

Water level in the generating zone of an electrode type boiler:

A) Is maintained by means of a feedwater regulator
B) Has no effect on pressure
C) Is constant
D) Is governed by feedwater flow
E) Is governed by load fluctuations

Answer 4

E) Is governed by load fluctuations

Question 5

A “rise of steam pressure” in the generating zone of an electrode boiler leads to:

A) A requirement of more feedwater
B) More steam output
C) A drop in water level in the generating zone
D) A rise in water level
E) More current demand

Answer 5

C) A “drop in water level” in the generating zone

Question 6

Immersion boiler tube bundles:

A) Operate at only one voltage
B) Can be removed from the unit for maintenance purposes
C) Act to conduct current through the water
D) Have very low electrical resistance
E) Cannot be used to regulate steaming capacity

Answer 6

B) Can be removed from the unit for maintenance purposes

Question 7

Electric boilers:

A) Require sootblowers when fuel is coal
B) Require tall stacks for pollution dispersement
C) Have energy conversion efficiencies close to 100%
D) Tend not to be very compact
E) Are not as safe as other boilers

Answer 7

C) Have energy conversion efficiencies close to 100%

Question 8

In an electrode type electric boiler the generating zone:

A) Generates more steam as water level falls
B) Uses more current when water level rises
C) Is less efficient than an immersion type
D) Generates more steam as water level rises
E) Is less efficient when water level rises

Answer 8

D) Generates more steam as “water level rises”

Question 9

Due to the effect of high temperature on the electrodes, Electric boilers are:

A) Operated at pressure up to 2100 psi
B) Operated at lower pressures below 2100 kPa
C) Able to withstand any pressure
D) Required to be used only for large scale industrial processes
E) Limited to 1100 kPa

Answer 9

B) Operated at lower pressures “below 2100 kPa”

Note:Below 2100kPa