Boiler Operator 3rd-test 1-2 Blue Book

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Boilers are redundantly safe due to the safety controls in it and most accidents are due to human error. Just how ready are you to tackle the upcoming exam on boilers? Take up the Boiler Operator 3rd-test from 1-2 of the Blue Book and refresh your memory on what we covered. All the best!

• 1.

____ are necessary for complete combustion.

• A.

Forced Draft, turbulence, and heat

• B.

Fuel oil, air, time, and mixture

• C.

Time, temperature, mixture, and atomization

• D.

Time, temperature, and draft

C. Time, temperature, mixture, and atomization
Explanation
In order for complete combustion to occur, several factors are necessary. Time is needed to allow the fuel and air mixture to fully react and burn. Temperature is required to reach the ignition point and sustain the combustion process. The mixture of fuel and air needs to be in the correct ratio for efficient burning. Atomization is also important as it breaks down the fuel into small droplets, increasing the surface area for better combustion. Therefore, all four factors - time, temperature, mixture, and atomization - are necessary for complete combustion.

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• 2.

If the steam pressure gauge indicates 200 psig, the absolute pressure is ____ psia.

• A.

14.7

• B.

185.3

• C.

214.7

• D.

228.7

C. 214.7
Explanation
The absolute pressure is calculated by adding the atmospheric pressure to the gauge pressure. Since the atmospheric pressure is typically around 14.7 psia, and the gauge pressure is given as 200 psig (which means it is measured relative to atmospheric pressure), the absolute pressure can be found by adding 14.7 psia to 200 psig. This gives a result of 214.7 psia.

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• 3.

A boiler is operating at 400 psi, and the safety valve opens at 410 psi and closes at 398 psi.  The blowdown is ____ psi.

• A.

10

• B.

12

• C.

12.5

• D.

14.7

B. 12
Explanation
The blowdown is the difference between the opening and closing pressure of the safety valve. In this case, the safety valve opens at 410 psi and closes at 398 psi. Therefore, the blowdown is 410 psi - 398 psi = 12 psi.

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• 4.

An oil cooler is commonly used with a(n) ____ when operating in conjunction with a turbo-generator.

• A.

Steam turbine

• B.

Reciprocating steam engine

• C.

Feedwater heater

• D.

Air compressor

A. Steam turbine
Explanation
An oil cooler is commonly used with a steam turbine when operating in conjunction with a turbo-generator because the steam turbine generates a significant amount of heat, which can cause the oil in the system to overheat. The oil cooler helps to regulate the temperature of the oil by dissipating the excess heat, ensuring that the system operates efficiently and preventing damage to the equipment.

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• 5.

A boiler is producing 40,000 lb of steam/hr at a pressure of 100 psi and a steam temperature of 500*F.  The steam produced is ____ steam.

• A.

Supersaturated

• B.

Desuperheated

• C.

Superheated

• D.

Saturated

C. Superheated
Explanation
The given information states that the boiler is producing steam at a pressure of 100 psi and a temperature of 500Â°F. In order for the steam to be superheated, it must be at a temperature higher than its saturation temperature at that pressure. Since the given temperature is higher than the saturation temperature, the steam produced by the boiler is superheated.

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• 6.

The economizer on a boiler is used to ____.

• A.

Heat air for combustion

• B.

Increase steam temperature

• C.

• D.

Keep tubes clean

Explanation
The economizer on a boiler is a heat exchanger that preheats the feedwater before it enters the boiler. It accomplishes this by transferring heat from the flue gases to the incoming feedwater. This process helps to increase the overall efficiency of the boiler system by reducing the amount of fuel required to heat the water to the desired temperature. Therefore, the economizer is used to add heat to the feedwater.

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• 7.

Soot blowers are normally used with ____ boilers.

• A.

Scotch marine

• B.

Cast iron

• C.

Firetube

• D.

Watertube

D. Watertube
Explanation
Soot blowers are normally used with watertube boilers. Watertube boilers have water-filled tubes that are heated externally by hot gases, allowing for a higher heat transfer rate and greater efficiency. However, the combustion process in these boilers can produce soot and other deposits that can accumulate on the tube surfaces and reduce heat transfer efficiency. Soot blowers are used to remove these deposits by directing high-pressure steam or air onto the tube surfaces, ensuring optimal performance and preventing damage to the boiler.

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• 8.

Overheating of tubes on a boiler can be caused by ____.

• A.

Rapid circulation of water

• B.

Scale on tubes

• C.

A high water level

• D.

A low firing rate

B. Scale on tubes
Explanation
Scale on tubes can cause overheating of tubes on a boiler. Scale is a hard deposit that forms on the inner surface of the tubes due to the precipitation of minerals in the water. This scale acts as an insulating layer, reducing the heat transfer efficiency and causing the tubes to overheat. As a result, the temperature of the tubes increases, leading to potential damage and failure of the boiler system. Regular maintenance and descaling of the tubes are necessary to prevent overheating and ensure the efficient operation of the boiler.

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• 9.

Carbon dioxide in a condensate return system causes ____.

• A.

Scale

• B.

Pitting

• C.

Channeling

• D.

Plugging of lines

C. Channeling
Explanation
Carbon dioxide in a condensate return system causes channeling. Channeling refers to the formation of channels or pathways within the system due to the corrosive nature of carbon dioxide. This can lead to uneven distribution of condensate and hinder the proper functioning of the system.

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• 10.

A ____ pump is a positive displacement pump.

• A.

Centrifugal

• B.

Recriprocating

• C.

Jet

• D.

Vacuum

B. Recriprocating
Explanation
A reciprocating pump is a positive displacement pump because it uses a piston or plunger to create a reciprocating motion, which in turn creates a suction and discharge action that moves the fluid through the pump. This type of pump is known for its ability to deliver a consistent flow rate and handle high pressures, making it suitable for applications where precise control and high pressure are required. In contrast, centrifugal, jet, and vacuum pumps are not positive displacement pumps as they rely on different mechanisms to move fluids.

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• 11.

A boiler generating 6,000 lb of steam/hr produces ____ Btu/hr.

• A.

6,000

• B.

60,000

• C.

600,000

• D.

6,000,000

D. 6,000,000
Explanation
A boiler generating 6,000 lb of steam/hr produces 6,000,000 Btu/hr because 1 lb of steam contains approximately 1,000 Btu of energy. Therefore, 6,000 lb of steam would contain 6,000,000 Btu of energy.

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• 12.

A bottom blowdown is performed on a boiler to ____.

• A.

Remove surface scum

• B.

Test for water level

• C.

Test safety valves

• D.

Discharge sludge and sediment

D. Discharge sludge and sediment
Explanation
Bottom blowdown is a process in which water and sediment that have settled at the bottom of the boiler are discharged to remove sludge and sediment. This helps to maintain the efficiency and performance of the boiler by preventing the accumulation of impurities that can hinder heat transfer and lead to corrosion. Removing sludge and sediment also helps to prevent blockages in the boiler's pipes and valves. Therefore, the correct answer is to discharge sludge and sediment.

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• 13.

Water columns are connected to the boiler with a minumum of ____ " pipe.

• A.

3/4

• B.

1

• C.

1 1/4

• D.

1 1/2

B. 1
Explanation
The water columns are connected to the boiler with a minimum of 1" pipe. This indicates that the pipe size should be at least 1 inch in diameter for proper connection between the water columns and the boiler.

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• 14.

The minumum size of a water column blowdown valve is ____ ".

• A.

1/2

• B.

3/4

• C.

1

• D.

1 1/4

B. 3/4
Explanation
The minimum size of a water column blowdown valve is 3/4. This means that the valve should have a diameter of at least 3/4 inch in order to effectively release the water in the water column. A smaller size valve may not be able to handle the flow of water and could result in inadequate blowdown, leading to issues with the water column system.

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• 15.

The maximum size bottom blowdown valves on boilers is ____ ".

• A.

1

• B.

1 1/2

• C.

2

• D.

2 1/2

D. 2 1/2
Explanation
The maximum size bottom blowdown valves on boilers is 2 1/2. This means that the largest size for the bottom blowdown valves on boilers is 2 1/2 inches. This size is determined based on the specific requirements and design of the boiler system, and it is important to ensure that the blowdown valves are properly sized to effectively remove sediment and impurities from the boiler.

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• 16.

A ____ allows condensate to pass through, but stops steam.

• A.

Steam trap

• B.

Siphon

• C.

Check valve

• D.

Bypass

A. Steam trap
Explanation
A steam trap is a device that allows condensate (the liquid form of steam) to pass through, but stops steam from flowing. It is designed to remove condensate from steam systems while preventing the loss of valuable steam. This helps to maintain the efficiency of the system and prevent damage to equipment.

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• 17.

When taking over a shift, the first thing to do is check the ____.

• A.

Water level in each boiler

• B.

Fuel supply

• C.

Flame condition

• D.

Feedwater pumps

A. Water level in each boiler
Explanation
When taking over a shift, checking the water level in each boiler is the first thing to do because it is crucial for the safe and efficient operation of the boiler. If the water level is too low, it can lead to overheating and damage to the boiler. On the other hand, if the water level is too high, it can cause water carryover into the steam system, leading to poor steam quality and potential damage to equipment downstream. Therefore, monitoring the water level ensures that the boiler is operating within safe limits and allows for timely adjustments to maintain optimal water levels.

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• 18.

According to the ASME code, a high-pressure boiler having more than 500 sq ft of heating surface shall have ____.

• A.

One safety valve of the proper size

• B.

One safety valve with a rupture disc

• C.

Two lever type safety valves

• D.

Two or more safety valves

D. Two or more safety valves
Explanation
According to the ASME code, a high-pressure boiler having more than 500 sq ft of heating surface shall have two or more safety valves. This is because having multiple safety valves ensures redundancy and provides a backup in case one valve fails or malfunctions. It helps to maintain the required pressure limits and ensures the safety of the boiler by preventing overpressure situations.

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• 19.

The probable cause of an increase in the temperature of gases of combustion at the boiler outlet is ____.

• A.

The burner is on low fire

• B.

The steam pressure is too low

• C.

Dirty heating surfaces

• D.

High combustion efficiency

C. Dirty heating surfaces
Explanation
Dirty heating surfaces can cause an increase in the temperature of gases of combustion at the boiler outlet. When the heating surfaces are dirty, it hinders the transfer of heat from the combustion gases to the water, resulting in a higher temperature of the gases leaving the boiler. This can lead to reduced boiler efficiency and potential overheating of the equipment. Regular cleaning and maintenance of the heating surfaces are essential to ensure optimal heat transfer and prevent excessive temperatures.

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• 20.

Boilers in battery equipped with ____ must have two main steam stop valves and a free-blowing drain between them.

• A.

Common blowdown lines

• B.

Manhole openings

• C.

Handhole openings

• D.

Continuous blowdown lines

B. Manhole openings
Explanation
Boilers in battery equipped with manhole openings must have two main steam stop valves and a free-blowing drain between them. Manhole openings are used for accessing the interior of the boiler for inspection, cleaning, and maintenance purposes. The two main steam stop valves ensure that the steam flow can be shut off completely when needed. The free-blowing drain between the valves allows for the removal of any condensate or impurities that may accumulate in the system. This setup ensures the safe and efficient operation of the boiler system.

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• 21.

In order to be sure the gauge glass is indicating an accurate water level reading, the stationary engineer should ____.

• A.

Shut the valve to the steam side of the gauge glass

• B.

Shut the valve to the water side of the gauge glass

• C.

Blow down the gauge glass

• D.

Blow down the water column

C. Blow down the gauge glass
Explanation
To ensure that the gauge glass is showing an accurate water level reading, the stationary engineer should blow down the gauge glass. This process involves opening the valve at the bottom of the gauge glass to release any sediment or impurities that may have accumulated, ensuring a clear and accurate view of the water level. Blowing down the gauge glass helps to prevent false readings and ensures the safe and efficient operation of the system.

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• 22.

A continuous blowdown line is located ____.

• A.

At the NOWL

• B.

In the mud drum

• C.

In the flash tank

• D.

In the steam and water drum well below the NOWL

D. In the steam and water drum well below the NOWL
Explanation
The continuous blowdown line is located in the steam and water drum well below the normal operating water level (NOWL). This placement ensures that the blowdown line is able to remove impurities and excess solids from the boiler system effectively. By being positioned below the NOWL, the blowdown line can efficiently drain water and maintain the desired water level in the drum.

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• 23.

A temperature reading of 80*C is equal to ____ *F.

• A.

52

• B.

148

• C.

168

• D.

176

D. 176
Explanation
The correct answer is 176. To convert Celsius to Fahrenheit, you multiply the temperature by 9/5 and add 32. So, to convert 80*C to *F, you would multiply 80 by 9/5 and add 32, which equals 176.

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• 24.

A chimney temperature of 250*F above steam temperature indicates ____.

• A.

Superheated steam

• B.

Poor efficiency

• C.

Saturated steam

• D.

Normal operation

B. Poor efficiency
Explanation
A chimney temperature of 250Â°F above steam temperature indicates poor efficiency because it suggests that a significant amount of heat is being lost through the chimney instead of being utilized to generate steam. This indicates that the system is not operating efficiently and is wasting energy.

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• 25.

A manometer is read in ____.

• A.

Inches of water

• B.

Psig

• C.

Psia

• D.

None of the above

A. Inches of water
Explanation
A manometer is a device used to measure pressure, particularly in fluid systems. It consists of a U-shaped tube filled with a liquid, usually water, and the pressure difference between the two ends of the tube causes the liquid level to change. The measurement is then read in terms of the height of the liquid column, typically in inches of water. Therefore, the correct answer is inches of water.

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• 26.

The boiling point of water will ____ with an increase in pressure.

• A.

Not change

• B.

Be raised

• C.

Be lowered

• D.

Raise until 212 *F

B. Be raised
Explanation
An increase in pressure will cause the boiling point of water to be raised. This is because as pressure increases, the molecules in the water are pushed closer together, making it more difficult for them to escape into the gas phase. Therefore, a higher temperature is required for the water to reach its boiling point and convert into vapor.

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• 27.

If a lather is not obtained when performing a soap hardness test, the water sample is ____.

• A.

Alkaline

• B.

Normal

• C.

Soft

• D.

Hard

D. Hard
Explanation
If a lather is not obtained when performing a soap hardness test, it indicates that the water sample is hard. Hard water contains high levels of minerals such as calcium and magnesium ions, which interfere with the formation of lather when soap is added. This is because these minerals react with the soap to form insoluble compounds, preventing the formation of a lather.

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• 28.

Combustion efficiency can be increased when air is ____.

• A.

Filtered

• B.

Mixed with CO2

• C.

Preheated

• D.

Dried

C. Preheated
Explanation
Preheating the air before combustion increases the temperature of the air entering the combustion chamber. This increase in temperature leads to better fuel vaporization and more complete combustion, resulting in higher combustion efficiency. Preheating also reduces the amount of heat required to raise the air temperature to the combustion level, which can improve overall energy efficiency. Therefore, preheating the air is an effective method to increase combustion efficiency.

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• 29.

____ draft is produced by a fan located between the boiler and the chimney.

• A.

Induced

• B.

Forced

• C.

Forced-induced

• D.

Natural forced

A. Induced
Explanation
An induced draft is produced by a fan located between the boiler and the chimney. This means that the fan creates a negative pressure in the system, causing the combustion gases to be drawn out of the boiler and pushed towards the chimney. This type of draft is commonly used in boilers to improve combustion efficiency and ensure proper ventilation.

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• 30.

The overspeed trip on a steam turbine should be tested ____.

• A.

Before putting the steam turbine on-line

• B.

Daily

• C.

Weekly

• D.

Monthly

A. Before putting the steam turbine on-line
Explanation
The overspeed trip on a steam turbine should be tested before putting the steam turbine online to ensure its proper functioning and safety. This test is crucial as it helps to detect any potential issues or malfunctions in the overspeed trip mechanism before the turbine is operated. By conducting this test before putting the turbine online, any necessary adjustments or repairs can be made to prevent accidents or damage to the turbine. Regular testing of the overspeed trip is essential for maintaining the overall reliability and performance of the steam turbine.

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• 31.

A high CO2 reading in the gases of combustion is a sign of ____.

• A.

Incomplete combustion

• B.

Carryover of oxygen

• C.

Low combustion efficiency

• D.

High combustion efficiency

D. High combustion efficiency
Explanation
A high CO2 reading in the gases of combustion indicates that the combustion process is efficient. This is because when fuel is burned efficiently, it produces more carbon dioxide (CO2) as a byproduct. Incomplete combustion would result in lower levels of CO2, as some of the fuel would not have been fully burned. Carryover of oxygen would also result in lower levels of CO2, as the excess oxygen would not have been utilized in the combustion process. Therefore, a high CO2 reading suggests that the combustion process is functioning effectively and efficiently.

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• 32.

The purpose of chemically treating feedwater is to ____.

• A.

Prevent priming

• B.

Turn scale forming salts to a nonadhering sludge

• C.

Change scale forming salts to an adhering sludge

• D.

Prevent water hammer

B. Turn scale forming salts to a nonadhering sludge
Explanation
Chemically treating feedwater is done to turn scale forming salts into a nonadhering sludge. This process helps to prevent the formation of scale deposits on the surfaces of equipment and pipes, which can lead to reduced heat transfer efficiency and potential equipment damage. By converting the scale forming salts into a nonadhering sludge, they can be easily removed from the system, reducing the risk of scale buildup and improving overall system performance.

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• 33.

Water in a deaerating feedwater heater is prevented from entering the steam line by a(n) ____.

• A.

Check valve

• B.

Stop valve

• C.

Loop seal or internal overflow

• D.

Atmospheric relief

C. Loop seal or internal overflow
Explanation
A loop seal or internal overflow is used to prevent water in a deaerating feedwater heater from entering the steam line. This mechanism ensures that only steam is allowed to pass through, while any water is redirected back into the feedwater heater. This helps maintain the purity of the steam and prevents any potential damage or contamination in the steam line.

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• 34.

A steam turbine operating at 3600 RPM will trip at ____ RPM.

• A.

3650

• B.

3700

• C.

3750

• D.

3960

D. 3960
Explanation
A steam turbine operating at 3600 RPM will trip at 3960 RPM because the trip speed is usually set slightly higher than the operating speed to allow for any sudden increase in load or other unexpected changes. This ensures that the turbine shuts down before it reaches a dangerous speed that could cause damage or failure.

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• 35.

The steam line going to the soot blowers is connected to the main ____.

• A.

• B.

Steam drum

• C.

Auxiliary line

• D.

Pressure reducing station

B. Steam drum
Explanation
The steam line going to the soot blowers is connected to the main steam drum. The steam drum is a vital component in a steam boiler system, serving as a reservoir for steam and water. It helps to separate the steam from water, ensuring dry steam is supplied to different parts of the system. The steam drum is typically connected to various steam lines, including the one going to the soot blowers, which are used to remove accumulated soot and ash from the boiler tubes.

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• 36.

Before using soot blowers on a boiler, ____.

• A.

Drain superheater lines

• B.

Drain soot blower lines

• C.

Secure all burners

• D.

Decrease the draft

B. Drain soot blower lines
Explanation
Before using soot blowers on a boiler, it is necessary to drain the soot blower lines. This is important because the soot blower lines may contain residual water or debris that could potentially cause damage or blockages if not properly drained. By draining the soot blower lines, any potential obstructions or contaminants can be removed, ensuring that the soot blowers function effectively and efficiently.

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• 37.

An accumulation of soot on the fire side of boiler tubes ____.

• A.

Increases boiler efficiency

• B.

Decreases boiler efficiency

• C.

Decreases gas temperature

• D.

Protects tubes from excessive heat

B. Decreases boiler efficiency
Explanation
An accumulation of soot on the fire side of boiler tubes decreases boiler efficiency. Soot acts as an insulator, preventing heat transfer from the combustion gases to the water in the tubes. This reduces the overall efficiency of the boiler as less heat is transferred to the water, resulting in higher fuel consumption to achieve the desired output. Additionally, the accumulation of soot can also lead to increased pressure drop and reduced airflow, further decreasing the efficiency of the boiler.

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• 38.

A globe valve installed in the feedwater line between the feedwater pump and boiler has pressure from the feedwater pump ____ the valve disc.

• A.

Under

• B.

On top of

• C.

Under and on top of

• D.

None of the above

A. Under
Explanation
The correct answer is "under". In a globe valve, the pressure from the feedwater pump is exerted on the underside of the valve disc. This allows the valve to open and allow the flow of feedwater from the pump to the boiler.

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• 39.

The range of a pressure gauge should be twice the safety valve setting, but not less than ____ time(s) the safety valve setting.

• A.

1

• B.

1 1/4

• C.

1 1/2

• D.

1 3/4

C. 1 1/2
Explanation
The range of a pressure gauge should be twice the safety valve setting to ensure accurate measurement. However, it should not be less than 1 1/2 times the safety valve setting. This ensures that the pressure gauge can accurately measure the pressure within the desired range and provide a margin of safety.

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• 40.

Hard scale formed on the inside of tubes is best removed by ____.

• A.

Washing down with water

• B.

Air or water driven turbines

• C.

Wire brushes

• D.

Boiling chemical solution

B. Air or water driven turbines
Explanation
Air or water driven turbines are the best option for removing hard scale formed on the inside of tubes. These turbines generate high-speed water or air flow, which can effectively break down and remove the scale from the tube surfaces. This method is efficient and can be used in various industries, such as power plants, where scale buildup is a common issue. Washing down with water, wire brushes, and boiling chemical solutions may not be as effective in removing hard scale compared to the force generated by air or water driven turbines.

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• 41.

To correct a low water condition, ____.

• A.

Decrease feedwater

• B.

Increase firing rate

• C.

Lower firing rate and increase feedwater

• D.

Secure fires

D. Secure fires
Explanation
To correct a low water condition, securing fires is the appropriate action. This means stopping or shutting off the source of heat or fuel that is causing the firing, which can help prevent further damage or potential hazards. By securing fires, the focus is on stopping the process that is causing the low water condition, allowing for necessary adjustments or repairs to be made.

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• 42.

The superheater drain is used to ____.

• A.

Remove gases from the superheater

• B.

Remove condensate

• C.

Relieve pressure

• D.

Establish steam flow

D. Establish steam flow
Explanation
The superheater drain is used to establish steam flow. This means that it is responsible for ensuring a continuous and uninterrupted flow of steam in the system. By removing any condensate or gases that may be present in the superheater, the drain helps to maintain the proper functioning of the superheater and allows for the efficient transfer of heat to the steam.

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• 43.

A sudden rise in chimney temperature with no increase in load indicates ____.

• A.

The damper is stuck closed

• B.

The boiler needs cleaning

• C.

There is a broken baffle

• D.

There is too much air

C. There is a broken baffle
Explanation
A sudden rise in chimney temperature with no increase in load indicates that there is a broken baffle. The baffle is a component in the boiler that helps direct the flow of combustion gases. When it is broken, it can cause the gases to bypass the heat exchanger and go directly up the chimney, leading to a rise in temperature. This issue should be addressed promptly to ensure the proper functioning and efficiency of the boiler.

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• 44.

The Btu content of natural gas is ____.

• A.

100,000 Btu/therm

• B.

100,000 Btu/cu ft

• C.

152,000 Btu/therm

• D.

152,000 Btu/cu ft

A. 100,000 Btu/therm
Explanation
The correct answer is 100,000 Btu/therm. This is because a therm is a unit of measurement for natural gas and is equivalent to 100,000 British thermal units (Btu). Therefore, the Btu content of natural gas is 100,000 Btu per therm.

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• 45.

The safety valve setting on the steam and water drum is ____ the superheater safety valve.

• A.

Lower than

• B.

Higher than

• C.

The same as

• D.

None of the above

B. Higher than
Explanation
The safety valve setting on the steam and water drum is higher than the superheater safety valve. This means that the pressure at which the safety valve on the steam and water drum will open is set to a higher value compared to the pressure at which the superheater safety valve will open. This is done to ensure that the pressure in the steam and water drum is released first before the pressure in the superheater, thus prioritizing the safety of the drum.

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• 46.

The Btu content of No. 6 fuel oil is approximately ____.

• A.

18,750 Btu/gal

• B.

18,750 Btu/lb

• C.

18,750 Btu/barrel

• D.

150,000 Btu/lb

B. 18,750 Btu/lb
Explanation
The Btu content of No. 6 fuel oil is approximately 18,750 Btu/lb. This means that for every pound of No. 6 fuel oil, there is approximately 18,750 British thermal units of energy. This measurement is commonly used to determine the energy content and efficiency of fuels.

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• 47.

Chemicals can be added to a boiler by a ____ pump.

• A.

Feedwater

• B.

Vacuum

• C.

Proportioning

• D.

Turbine

C. Proportioning
Explanation
Chemicals can be added to a boiler by a proportioning pump. This type of pump is specifically designed to accurately measure and inject chemicals into the feedwater of the boiler. The proportioning pump ensures that the chemicals are added in the correct ratio, maintaining the desired water chemistry and preventing any potential issues such as corrosion or scale buildup.

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• 48.

The feedwater stop valve is found between the ____.

• A.

Boiler and check valve

• B.

Check valve and feedwater pump

• C.

Boiler and feedwater pump

• D.

A. Boiler and check valve
Explanation
The feedwater stop valve is located between the boiler and the check valve. This valve controls the flow of feedwater into the boiler, allowing it to enter only when necessary. The check valve, on the other hand, prevents backflow of steam or water from the boiler into the feedwater system. Placing the feedwater stop valve between these two components ensures that the flow of feedwater is regulated and that there is no risk of contamination or damage to the system.

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• 49.

Sensible heat is ____.

• A.

Heat that can be measured with a thermometer

• B.

970.3 Btu

• C.

Heat that cannot be measured

• D.

Heat that changes a substance's state but not its temperature

A. Heat that can be measured with a thermometer
Explanation
Sensible heat refers to the heat that can be measured using a thermometer. This means that it is the heat that can be detected and quantified using temperature measurements. Sensible heat is associated with changes in temperature, indicating the amount of thermal energy present in a substance. Therefore, the correct answer is "heat that can be measured with a thermometer."

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• 50.

Balanced draft is ____.

• A.

Forced draft

• B.

Induced draft

• C.

Below atmospheric pressure at the flue outlet

• D.

Constant furnace pressure slightly below atmospheric pressure

D. Constant furnace pressure slightly below atmospheric pressure
Explanation
A balanced draft refers to a system where the pressure inside the furnace is maintained at a constant level that is slightly below atmospheric pressure. This ensures that there is a steady flow of air into the furnace, preventing any unwanted backflow or leakage. This constant pressure helps in maintaining efficient combustion and controlling the flow of flue gases.

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• Current Version
• Sep 18, 2023
Quiz Edited by
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• Dec 23, 2009
Quiz Created by
Mikdenluv

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