Unit6 Water Treatment Flashcards
Carbon dioxide may cause corrosion in condensate return lines. This corrosive carbon dioxide may originate:
Select one:
a. by absorption in the deaerator
b. as sodium sulfite in the boiler water
c. by decomposition of bicarbonates in the boiler water
d. In condensate neutralizing amines
c. by decomposition of bicarbonates in the boiler water
When only one specific type of metal is subject to corrosive attack, the corrosion process is called:
Select one:
a. anodic corrosion
b. cathodic corrosion
c. selective leaching
d. galvanic corrosion
c. selective leaching
The main scale forming substance in cooling water towers is: Select one: a. Magnesium carbonate b. Sodium sulfite c. Calcium bicarbonate d. Sodium phosphate
c. Calcium bicarbonate
Sludge is usually removed from a boiler by:
Select one:
a. Filtering the water before it leaves the boiler
b. Vacuuming it from the bottom
c. Blowing off through the bottom blowoff connection
d. Blowing down through the continuous blowdown
c. Blowing off through the bottom blowoff connection
Sodium sulfite:
Select one:
a. Prevents the corrosion caused by oxygen in boiler water
b. Precipitates calcium and magnesium compounds
c. Prevents scale adhering to the tubes
d. Controls foaming
a. Prevents the corrosion caused by oxygen in boiler water
Direct measurement of condensate amine can be done using:
Select one:
a. a commercially available iron analysis kit.
b. methyl purple and sulfuric acid
c. a chromatograph or a fluorometer
d. a coupon rack
c. a chromatograph or a fluorometer
To minimize galvanic corrosion
Select one:
a. If dissimilar metals are used, they must be directly connected to each other.
b. The electrochemical potential difference between any two connected materials must be greater than 0.15 V.
c. Use only noble metals.
d. A sacrificial anode may be installed to protect the cathodic materials.
d. A sacrificial anode may be installed to protect the cathodic materials.
When testing boiler water, a conductivity meter is used to measure:
Select one:
a. Total alkalinity
b. Hardness in parts per million or grains per gallon
c. Total suspended matter
d. Total dissolved solids
d. Total dissolved solids
The wood used in cooling towers contains natural compounds called __________, that resist decay.
Select one:
a. extractives
b. celluloses
c. lignins
d. biocides
a. extractives
Water filters must be cleaned: Select one: a. If the water becomes hard b. When the dissolved solids are high c. By backwashing the filter media d. By chemically cleaning the filter media
c. By backwashing the filter media
What checks should be done yearly on heating or cooling systems that contain glycol?
Select one:
a. check for increasing pH and dissolved carbon dioxide
b. check for viscosity and pour point
c. check toxicity and specific heat
d. check for freeze point and inhibitor strength
d. check for freeze point and inhibitor strength
In condenser cooling water systems, sacrificial anodes work by
Select one:
a. neutralizing acidic compounds.
b. plating other metal parts with non-corrosive metal ions.
c. interfering with the formation of corrosion products in a corrosion cell reaction.
d. corroding preferentially over components made of other metals.
d. corroding preferentially over components made of other metals.
What is the purpose of corrosion coupons?
Select one:
a. They are used to prevent galvanic corrosion
b. They attract corrosion products and keep them from depositing in the condensate system.
c. They detect the presence of corrosive non-condensable gases.
d. They are used to determine corrosion rates
d. They are used to determine corrosion rates
A conductivity meter is used to measure the: Select one: a. Alkalinity b. Electrolyte c. Hardness d. Total Dissolved Solids
d. Total Dissolved Solids
If heating or cooling system water may come into contact with food products, ___________ is used to keep the water from freezing.
Select one:
a. octyl alcohol
b. ethylene glycol
c. propylene glycol
d. methanol
c. propylene glycol
If flow is too high, the resin in a sodium zeolite softener may be discharged to sewer during the \_\_\_\_\_\_\_\_\_ stage. Select one: a. Service b. Slow rinse c. Fast rinse d. Backwash
d. Backwash
Boiler water that is too alkaline will likely:
Select one:
a. Produce scale inside the boiler
b. Have a low pH
c. Cause foaming in the boiler
d. Cause grooving on a boiler’s waterside surfaces
c. Cause foaming in the boiler
Where does the carbonic acid found in condensate come from?
Select one:
a. From inorganic compounds that enter through leaking heat exchangers.
b. From under-feeding oxygen scavengers to the boiler drum.
c. From the oxidation of carbon steel condensate piping.
d. From the decomposition of dissolved carbonates and bicarbonates in the boiler water.
d. From the decomposition of dissolved carbonates and bicarbonates in the boiler water.
Grooving and general thinning of the condensate return system is a result of:
Select one:
a. oxygen corrosion
b. scale build-up
c. carbonic acid corrosion
d. high alkalinity
c. carbonic acid corrosion
How does one type of amine protect a condensate system?
Select one:
a. By forming a protective film coating on scale forming solids
b. By neutralizing carbonic acid
c. By scavenging oxygen from the condensate
d. By neutralizing hydroxide alkalinity
b. By neutralizing carbonic acid
Phenolphthalein:
Select one:
a. Turns pink in the presence of hydroxide and carbonate alkalinity
b. Is fed to cast iron boilers
c. Prevents caustic embrittlement
d. Indicates the presence of dissolved oxygen
a. Turns pink in the presence of hydroxide and carbonate alkalinity
Total alkalinity is measured:
Select one:
a. Using methyl purple indicator and sulfuric acid
b. Using potassium iodide-iodate and EDTA
c. To control the concentration of oxygen scavenger
d. Using phenolphthalein and sulfuric acid
d. Using phenolphthalein and sulfuric acid
In cooling towers, sacrificial anodes work by
Select one:
a. plating the metal parts with non-corrosive metal ions.
b. corroding, instead of the metal cooling tower parts
c. neutralizing acidic compounds.
d. interfering with the formation of corrosive reaction products.
b. corroding, instead of the metal cooling tower parts
The principal cause of steel corrosion in cooling towers is: Select one: a. Dissolved carbon dioxide b. High pH c. Dissolved oxygen d. Low pH
c. Dissolved oxygen
A water sample taken from the service outlet of an ion-exchange softener shows 20 ppm hardness. The operator should:
Select one:
a. Regenerate the softener.
b. Backwash the softener.
c. Add salt to the brine tank.
d. Rinse the softener.
a. Regenerate the softener.
) The dissolved solids in raw water: Select one: a. Cause pitting of boiler surfaces b. Cause grooving of piping surfaces c. Are organic matter d. Are usually removed by ion exchange
d. Are usually removed by ion exchange
Total boiler water alkalinity is a measurement of dissolved:
Select one:
a. Carbonates, sulfates, and bicarbonates
b. Bicarbonates and chelants
c. Hydroxides, bicarbonates, and carbon dioxide
d. Hydroxides, carbonates, and bicarbonates
d. Hydroxides, carbonates, and bicarbonates
Scaling is not as severe in cooling towers when compared to boilers because:
Select one:
a. Cooling towers evaporate less water
b. There are not as many dissolved solids in cooling tower water
c. Water temperatures are not as high in cooling towers as they are in boilers
d. Cooling tower water is constantly being aerated
c. Water temperatures are not as high in cooling towers as they are in boilers
Dissolved gases, such as oxygen and carbon dioxide, can be removed by a process known as: Select one: a. Deaeration b. Sedimentation c. Scrubbing d. Clarification
a. Deaeration
During the “Rinse” stage when regenerating a sodium zeolite softener, the solution going to the sewer contains: Select one: a. Calcium sulphate b. Sulphates and bicarbonates c. Calcium and magnesium ions d. Sodium bicarbonates and sulphates
c. Calcium and magnesium ions
By definition, alum, when added to water to form floc in a clarifying system, is known as a: Select one: a. Curdler b. Congealant c. Coagulant d. Flocculant
d. Flocculant
Heat exchanger coils that use ethylene glycol:
Select one:
a. Do not require air vents.
b. Are not recommended for use in heating and air conditioning systems in the food industry.
c. Use direct fired boilers as their heat source.
d. Give reasonable heat transfer efficiency at low glycol velocity.
b. Are not recommended for use in heating and air conditioning systems in the food industry.
The P-alkalinity is 220 ppm. The M-alkalinity is 240 ppm. What is the OH- alkalinity?
Select one:
a. 200 ppm
b. 80 ppm
c. 0 ppm
d. 40 ppm
a. 200 ppm
To prevent scale formation, \_\_\_\_\_\_\_\_ is added to the boiler water. Select one: a. Zeolite b. Sodium chloride c. Amine d. Phosphate
d. Phosphate
Which of these processes removes suspended matter from plugged filter beds? Select one: a. Regeneration b. Flushing c. Rinsing d. Backwashing
d. Backwashing
A treatment method that is often used in conjunction with settling tanks is: Select one: a. Zeolite softening b. De-mineralizing c. Lime soda softening d. Filtration
d. Filtration
Bicarbonates can be removed from boiler feedwater by:
Select one:
a. Filter tanks
b. A strainer in the feedwater line
c. Heating the water to just below its boiling point
d. Blowing off the boiler
c. Heating the water to just below its boiling point
In a galvanic corrosion cell, the metal that corrodes is the
Select one:
a. anode
b. cathode
c. metal with the more positive electrochemical potential
d. noble metal
a. anode
Caustic embrittlement of boiler metal is promoted by: Select one: a. Concentrations of sodium hydroxide b. Concentration of sodium chloride c. Overheating of boiler parts d. Concentration of sodium sulfite
a. Concentrations of sodium hydroxide
Lime-soda softeners:
Select one:
a. Remove all dissolved solids from the water
b. Remove all dissolved solids and gases from the water
c. Remove lime from groundwater
d. Remove the scale forming dissolved solids
d. Remove the scale forming dissolved solids
In a steam plant, condensate treatment is necessary
Select one:
a. to provide clean, potable drinking water.
b. to aerate the condensate before it enters the deaerator.
c. because condensate can contain impurities harmful to boilers and condensate return systems.
d. to provide ultra-pure boiler feedwater.
c. because condensate can contain impurities harmful to boilers and condensate return systems.
Chemicals are fed to a watertube boiler:
Select one:
a. With a small centrifugal pump
b. Into the top drum only
c. With a small positive displacement pump
d. With a hand pump
c. With a small positive displacement pump
An acceptable pH value for boiler water is: Select one: a. 7.00 b. 6.95 c. 8.35 d. 10.50
d. 10.50
Dezincification is a form of
Select one:
a. selective leaching
b. dielectric corrosion
c. under-deposit corrosion
d. stress corrosion cracking
a. selective leaching
Poorly functioning deaerators:
Select one:
a. increase the likelihood of grooving and pitting corrosion in condensate systems
b. permit scale forming compounds to enter the condensate system
c. may overheat the feedwater
d. should be compensated for by increasing the amine feed
a. increase the likelihood of grooving and pitting corrosion in condensate systems
The "total" or "methyl" alkalinity test indicates the alkalinity that is due to: Select one: a. Dissolved carbon dioxide b. Sodium Bicarbonate ions c. Hydroxide alkalinity d. All forms of alkalinity
d. All forms of alkalinity
What is the consequence if condensate contains hardness?
Select one:
a. Corrosion by-products.
b. Pitting and grooving.
c. Reduced condensate line corrosion.
d. Boiler waterside scale deposition.
d. Boiler waterside scale deposition.
Coagulants, when added to water: Select one: a. Soften the water b. Will help remove fine particles c. Remove the dissolved solids d. Cause fine particles to float to the surface
c. Remove the dissolved solids
Sodium phosphates:
Select one:
a. Produce a light, protective scale on the boiler heat transfer surfaces
b. Prevent scale formation
c. Absorb dissolved oxygen and prevent CO3 pitting
d. Prevent the formation of sludge
b. Prevent scale formation
In feedwater, which of the following is an example of suspended matter? Select one: a. Sodium b. Sand c. Salt d. Calcium
b. Sand
Oxygen in condensate can cause:
Select one:
a. highly acidic water
b. scale deposition
c. low alkalinity
d. pitting corrosion
d. pitting corrosion
External deaeration:
Select one:
a. Removes dissolved gases from the water
b. Relies entirely on the addition of chemicals
c. Removes all dissolved gases and solids from the water
d. Only removes oxygen from the water
a. Removes dissolved gases from the water
Ethylene glycol:
Select one:
a. Has a lower heat transfer efficiency in comparison to propylene glycol
b. Creates less friction losses in heating coils and piping, in comparison to hot water
c. Requires a smaller pump and less horsepower, in comparison to hot water
d. Has a lower heat transfer efficiency, in comparison to hot water
d. Has a lower heat transfer efficiency, in comparison to hot water
Which of the following is a common test conducted on condensate?
Select one:
a. dissolved carbon dioxide
b. pH
c. dissolved oxygen
d. sulfite residual
b. pH
Filters are used: Select one: a. For external water treatment b. To remove dissolved solids c. To remove calcium bicarbonates d. For internal treatment
a. For external water treatment
Phenolphthalein is Select one: a. an indicator b. a reagent c. a buffer d. a neutralizing agent
a. an indicator
The component used to to prevent wasting steam through a deaerator vent is a: Select one: a. Cyclone separator b. Chevron drier c. Scrubber d. Vent condenser
d. Vent condenser
In cooling towers, structural wood is chemically attacked by a process called
Select one:
a. delignification
b. biological attack
c. cellulose deterioration
d. extractive leaching
a. delignification
Sodium zeolite softeners:
Select one:
a. Remove all dissolved solids and suspended matter from the water
b. Remove calcium and magnesium ions from the water
c. Are regenerated with an acid solution
d. Remove all dissolved solids from the water
b. Remove calcium and magnesium ions from the water
Sludge conditioning in a boiler:
Select one:
a. Is controlled by the continuous blowdown
b. Prevents pollution from the blowdown water
c. Prevents precipitates from adhering to boiler surfaces
d. Is done to mix the sludge with the boiler water
c. Prevents precipitates from adhering to boiler surfaces
the chemical to control boilers pH
Sodium Hydroxide (NAOH)- caustic soda
To prevent scale deposition in cooling towers
Select one:
a. Keep the cycles of concentration above 10.
b. Reduce the rate of tower blowdown.
c. Keep scale-forming salts in solution, using crystal modification chemicals.
d. Keep the pH of the water high.
c. Keep scale-forming salts in solution, using crystal modification chemicals.
Which of the following is a common test conducted on condensate?
Select one:
a. dissolved carbon dioxide
b. pH
c. dissolved oxygen
d. sulfite residual
b. pH
A boiler has an M-alkalinity that is greater than the prescribed control range. What is the appropriate operator response?
Select one:
a. Reduce the frequency of bottom blowoff.
b. Lower the boiler water level.
c. Increase the rate of sodium hydroxide feed.
d. Increase the rate of continuous blowdown.
d. Increase the rate of continuous blowdown.
In cooling towers, heavy metals, oxidizing chemicals, and non-oxidizing chemicals are used to:
Select one:
a. Inhibit corrosion
b. Inhibit biological fouling
c. Eliminate wood deterioration
d. Reduce scaling
b. Inhibit biological fouling
Condensate return line corrosion can be controlled by:
Select one:
a. Feeding sodium bicarbonate to the boiler
b. Adding sodium sulfite
c. Feeding amines
d. Adding polymers
c. Feeding amines
If heating or cooling system water may come into contact with food products, ___________ is used to keep the water from freezing.
Select one:
a. ethylene glycol
b. propylene glycol
c. methanol
d. octyl alcohol
b. propylene glycol
The chemical used to regenerate the cation exchanger of a demineralizer is: Select one: a. Hydrochloric acid b. Caustic soda c. Sodium hydroxide d. Sulfuric acid
d. Sulfuric acid - H2SO4
The normal loss of zeolite in a sodium zeolite softener is about \_\_\_\_\_\_\_ per year. Select one: a. 5% b. 3% c. 15% d. 10%
b. 3%
The dissolved solids in raw water: Select one: a. Cause pitting of boiler surfaces b. Cause grooving of piping surfaces c. Are organic matter d. Are usually removed by ion exchange
d. Are usually removed by ion exchange
Boiler water is treated in order to:
Select one:
a. prevent the water from becoming too alkaline
b. reduce the environmental impact of the blowoff effluent
c. remove suspended matter
d. prevent scale deposition and waterside corrosion
d. prevent scale deposition and waterside corrosion
Two common chemicals used for deaeration are sodium sulfite and: Select one: a. sodium hydroxide b. sodium sulfate c. hydrazine d. sodium phosphate
c. hydrazine
The chemical used to regenerate the anion exchanger of a demineralizer is: Select one: a. Caustic soda b. Sulfuric acid c. Sodium chloride d. Hydrochloric acid
a. Caustic soda - NaOH
Sodium hydroxide
Chemicals used for condensate system treatment include ________ and _______ amines.
Select one:
a. neutralizing and filming
b. aromatic and alkyl
c. acidifying and alkalizing
d. softening and neutralizing
a. neutralizing and filming
Chillers must have _____________ to protect the evaporator coil from freezing damage.
Select one:
a. anti-freeze
b. frost plugs
c. freeze stats
d. heaters
c. freeze stats
What checks should be done yearly on heating or cooling systems that contain glycol?
Select one:
a. check toxicity and specific heat
b. check for freeze point and inhibitor strength
c. check for viscosity and pour point
d. check for increasing pH and dissolved carbon dioxide
b. check for freeze point and inhibitor strength
Temporary hardness in feedwater is caused by: Select one: a. Sodium nitrate b. Magnesium bicarbonate c. Calcium carbonate d. Magnesium sulphate
b. Magnesium bicarbonate
If boiler feedwater is neutral, its pH is: Select one: a. 0 b. 5 c. 7 d. 9
c. 7
Where does the carbonic acid found in condensate come from?
Select one:
a. From under-feeding oxygen scavengers to the boiler drum.
b. From the decomposition of dissolved carbonates and bicarbonates in the boiler water.
c. From the oxidation of carbon steel condensate piping.
d. From inorganic compounds that enter through leaking heat exchangers.
b. From the decomposition of dissolved carbonates and bicarbonates in the boiler water.
In a zeolite water softener, the scale-forming salts are:
Select one:
a. Completely removed
b. Changed into non-scale forming sodium salts
c. Filtered out
d. Absorbed by the zeolite
b. Changed into non-scale forming sodium salts
In a galvanic corrosion cell, the metal that corrodes is the
Select one:
a. metal with the more positive electrochemical potential
b. noble metal
c. cathode
d. anode
d. anode
The biological growth in cooling tower water that causes death is
Select one:
a. Legionella Bacteria
b. Pontiac Fever
c. Philadelphia Flu
d. Acute Lung Biofilm
a. Legionella Bacteria
Biological fouling in recirculating cooling water towers is caused by algae, \_\_\_\_\_ and bacteria growth. Select one: a. Flora b. Micro-organisms c. Fauna d. Fungi
d. Fungi
Which of the following is an example of a dissolved solid? Select one: a. Magnesium sulphate b. Oxygen c. Sand d. Carbon dioxide
a. Magnesium sulphate
Organic growth, also called \_\_\_\_\_\_\_\_ can reduce the flow rates in cooling tower tubes and channels. Select one: a. Algae b. Slime c. Fungi d. Avian waste
b. Slime
When a boiler “primes”, it means that:
Select one:
a. The water has not been chemically treated
b. The boiler is being over fired
c. Water is being carried over with the steam
d. The steam vent is open, to allow it to fill
c. Water is being carried over with the steam
Which of the following is NOT a cause of, or a factor in, closed loop system corrosion?
Select one:
a. caustic gouging
b. dissolved oxygen
c. low pH
d. galvanic action
a. caustic gouging
Dezincification is a form of
Select one:
a. selective leaching
b. under-deposit corrosion
c. stress corrosion cracking
d. dielectric corrosion
a. selective leaching
