Chapter 10 Flashcards
Encrustation of boiler water mineral deposits on water-side boiler heating surfaces is caused by what undesirable minerals?
1) Sodium Carbonate
2) Magnesium Phosphate
3) Calcium Carbonate
4) Magnesium Carbonate
5) Sodium Phosphate
Choose one right answer.
A) 2, 3, 4
B) 3, 4
C) 4, 5
D) 1, 2
E) 1, 2, 3, 4
B
When mineral scale forms on boiler heating surfaces, voids or pockets are created between the scale and the boiler water-side heating surfaces. Within these pockets pH becomes highly concentrated and can lead to a condition called:
A) Caustic Grooving
B) Caustic Pitting
C) Caustic Gouging
D) Caustic Embrittlement
C
Without proper boiler feed water treatment, one area predominately favorable to water side scaling in steam generators is the:
A) Economizer
B) Mud Drum
C) Steam Generating Tubes
D) Steam Drum
C
Without proper boiler feed water control, mineral hardness deposits can result in the following negative results:
1) Restricts heat transfer
2) Caustic Embrittlement
3) Corrosion
4) Chelation
5) Scale sloughing a plugging
Choose one right answer.
A) 1, 3, 5
B) 1, 2, 4
C) 1, 2
D) 1, 2, 5
E) 2, 3, 4
A
Complete the following Chemical Reaction. 3CaCO3 + 2Na3PO4 → Ca3(PO4)3 + ________
A) 3CaCO3
B) 2Na3PO4
C) 3Na2CO3
D) Ca3(PO4)3
C
Complete the following Chemical Reaction. 3MgCO3 + 2Na3PO4 → ________ + 3Na2CO3
A) 3MgCO3
B) 2Na3PO4
C) Mg3(PO4)2
D) 3Na2CO3
C
Complete the following Chemical Reaction. MgCO3 + ________ → Mg(OH)2 + Na2CO3
A) 2NaOH
B) MgCO3
C) Mg(OH)2
D) Na2CO3
A
The first line of attack in preventing boiler scale accumulation is to remove scale-forming minerals. Which 2 primary chemicals are used to suspend solids and where in the system are they added?
A) Phosphates and Calcium Carbonate and are added into the deaerator
B) Phosphates and Chelates are added into the boiler feed water pump
C) Phosphates and Sodium Hydroxide and are added into the deaerator
D) Phosphate and Magnesium Carbonate and are added into the boiler feed water pump
B
In reference to the disastrous effects of corrosion, there is one desirable corrosive activity which naturally promotes the formation of a protective layer on boiler water side surfaces. This very thin layer is called the:
A) Caustic Embrittlement Layer
B) Amine Filming Layer
C) Polymer layer
D) Magnetite Layer
D
Any success for a boiler feed water phosphate program depends on the ________ level of the boiler water being sufficiently high. Optimum results for precipitate efficiency occur when the pH of raw feed water is between ______ and ______.
A) Acidity, 8.5 – 9.5
B) Sulphite, 11 – 12
C) Alkalinity, 11 – 12
D) Solubility, 8.5 – 9.5
C
Boiler feed water pH should be maintained within the region of:
A) 8.5 to 12.7
B) 9.5 to 11.7
C) 8.0 to 11.5
D) 4.5 to 7.5
A
The following chemical Na3PO4 is used as a boiler water treatment and acts as a:
A) Sludge Conditioner
B) Anti-Corrosion Agent
C) Foaming Agent
D) Precipitating Agent
D
Oxygen (O2) corrosion in boiler water side components can be identified by small:
A) Cracks
B) Grooves
C) Scale
D) Pits
D
Carbon Dioxide (CO2) corrosion in boiler water side components can be identified by small:
A) Grooves
B) Pits
C) Scale
D) Cracks
A
Foaming on the surface of the boiler water can is caused by:
A) Polymers
B) Organics
C) Priming
D) Misting
B
