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Process Technology Equipment
Chapter 13 Furnaces
1. What type of furnace is designed to provide even temperature control for
process fluids?
A. Box furnace
B. Vertical furnace
C. Cabin furnace
D. Horizontal furnace
2. What type of furnace draft uses rotary blowers, driven by electric motors or
steam turbines?
A. Assisted draft
B. Induced draft
C. Natural draft
D. Balanced draft
3. What type of furnace draft uses two fans to facilitate airflow?
A. Assisted draft
B. Induced draft
C. Natural draft
D. Balanced draft
Process Technology Equipment
Chapter 13 Furnaces
4. What component of the furnace is located at or near the convection section?
A. Shock bank
B. Refractory lining
C. Purge system
D. Bridgewall
5. What component of a furnace is a bricklike form of insulation used inside
high-temperature furnaces?
A. Bridgewall
B. Purge system
C. Refractory lining
D. Shock bank tubes
Process Technology Equipment
Chapter 13 Furnaces
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6. What component of a furnace protects the convection section from direct
exposure to the radiant heat of the firebox?
A. Bridgewall
B. Purge system
C. Refractory lining
D. Shock bank tubes
7. What is used to purge combustibles from the firebox in natural draft furnaces?
A. Fans
B. Steam
C. Water
D. Coolers
8. What happens if the O2 levels are too low?
A. CO emissions may decrease.
B. CO emissions may increase.
C. NOx emissions may decrease.
D. NOx emissions may increase.
Process Technology Equipment
Chapter 13 Furnaces
9. What gives a visual indication of the airflow needed to maintain the target
pressure in the furnace chamber or duct?
A. Instrument control systems
B. Pressure gauge
C. Interlock control system
D. Draft control system
10. What are safety devices used to protect the furnace from developing
dangerous operating conditions?
A. Instrument control systems
B. Pressure gauges
C. Interlock control systems
D. Draft control systems
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Chapter 13 Furnaces
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11. Which of the following is an example of an item that can trip an interlock and
shut down a furnace?
A. High stack temperature
B. Low levels of O2 in the stack
C. Low levels of NOx in the stack
D. Low levels of CO in the stack
12. What may be the result of poor atomization of liquid fuels?
A. Coking
B. Fouling
C. Overheating
D. Pooling of liquids inside the firebox
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Chapter 13 Furnaces
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13. What collects on upper furnace tubes, causing oxidation failures and critically
attacking refractory insulation?
A. Excess fuel
B. Nitrogen oxide
C. Vanadium ash
D. Carburization
14. Which of the following is an external factor that contributes to furnace
problems?
A. Hot weather
B. Increased steam supply
C. Extremely wet weather
D. Downstream process upsets
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Chapter 13 Furnaces
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15. Which of the following hazards can cause a sudden drop in box pressure?
A. Bypassing safety interlocks
B. Poor control of excess air and poor draft control
C. Failure to follow flame safety procedure
D. Opening furnace inspection ports when the firebox pressure is greater than
atmospheric pressure
16. Which of the following is a proper response when faced with an uncontrolled
fire?
A. Open the damper.
B. Shut off all fuels.
C. Locate a supervisor.
D. Flood the firebox with water.
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Chapter 13 Furnaces
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17. Which of the following is a personal safety precaution you should follow with
regard to furnaces?
A. Stand directly in front of the furnace when opening the inspection door.
B. Limit contact with the control room operator.
C. Always wear long sleeves.
D. Always wear flammable clothing when required.
18. What is caused by incomplete combustion of fuels?
A. Smoke
B. NOx
C. CO
D. SOx
19. Which of the following can be a result of deviating from normal furnace
operation?
A. Loss of production
B. Loss of product quality
C. Fines from emissions outside permitted standards
D. All of the above
Process Technology Equipment
Chapter 13 Furnaces
Page 28
20. Which of the following should be included in a process technician’s
inspection of the furnace?
A. Examine the external metal skin for hot spots.
B. Examine the fuel for uniform color and size.
C. Examine the furnace’s internal components.
D. Examine the viscosity of the fuel source.
21. What furnace components are susceptible to damage from thermal shock?
A. Tubes
B. Safety interlocks
C. Refractory materials
D. Firebox
Answers:
Process Technology Equipment
Chapter 13 Furnaces
Page 29
Clicker Questions
(Note to Instructor: If you have clicker capability in your institution, you may want to
include some of these questions as appropriate. Or perhaps you just want to use them
as a way to check the students’ understanding of the content.)
1. What type of furnace is used in high-temperature processes?
A. Box furnace
B. Vertical furnace
C. Cabin furnace
D. Cylindrical furnace
2. When heavier liquid fuels are used, heat must be applied to reduce _________.
A. density
B. viscosity
C. temperature
D. pressure
Process Technology Equipment
Chapter 13 Furnaces
3. What is the auto-ignition temperature of most fuels used in the process
industries?
A. 200–300 degrees Fahrenheit
B. 50–700 degrees Fahrenheit
C. 800–1300 degrees Fahrenheit
D. 1500–2000 degrees Fahrenheit
4. Which of the following hazards can cause an explosion in the firebox?
A. Bypassing safety interlocks
B. Poor control of excess air and poor draft control
C. Failure to wear proper protective equipment
D. Opening furnace inspection ports when the firebox pressure is greater than
atmospheric pressure
Process Technology Equipment
Chapter 13 Furnaces
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5. What typically forms from the incomplete combustion of a fuel containing
carbon?
A. Smoke
B. NOx
C. CO
D. SOx
Process Technology Equipment
Chapter 13 Furnaces
Page 32
APPENDIX, Chapter 13
Table of Contents
Contents
Page
Checking Your Knowledge Answer
Key
33
Process Technology Equipment
Chapter 13 Furnaces
Checking Your Knowledge Answer Key
1. Define the following terms:
a. Pilot
b. Stack
c. Burner
d. Firebox
e. Induced draft furnace
f. Natural draft furnace
g. Air register
h. Vertical furnace
i. Shock bank
j. Radiant tube
k. Cabin furnace
l. Radiant section
m. Refractory lining
Process Technology Equipment
Chapter 13 Furnaces
2. Furnaces are used to:
a. increase the temperature of a fluid
b. release harmful gases to the environment
c. decrease temperature and pressure
d. decrease the viscosity of a fluid
3. Which of the following is not a common type of furnace?
a. Cabin
b. Spherical
c. Box
d. Vertical
Process Technology Equipment
Chapter 13 Furnaces
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4. Select the components that are found in a furnace. (Select all that apply.)
a. Radiant tubes
b. Bridgewall
c. Fuel valve
d. Tube sheet
5. List three possible consequences on a furnace when there is insufficient air
and the furnace becomes too fuel-rich.
6. (True/False) Industrial furnaces are operated at positive pressure.
7. Periodic cleaning is required on the _______________.
a. stack
b. burner fuel lines
c. bridgewall
Process Technology Equipment
Chapter 13 Furnaces
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d. shock bank
8. Which of the following hazards can cause cooling of the furnace?
a. Poor control of excess air and draft control
b. Bypassing safety interlocks
c. Opening furnace inspection ports when the firebox pressure is greater than the
atmospheric pressure
d. Increasing the air into the furnace
9. (True/False) CO is an asphyxiant that can cause death in high enough
concentrations.
10. Which of the following is NOT a potential problem in furnace operation?
a. Quick start-up
b. Plugging of the process tubes
c. Positive pressure in the firebox
Process Technology Equipment
Chapter 13 Furnaces
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d. Uniform flame height and uniform process flame color
11. Match the furnace adjustment to its reason to achieve maximum efficiency and
lowest emissions.
1. Adjust the fuel to furnace to achieve
the correct
a. firebox pressure
2. Adjust the damper to achieve the
proper
b. O2 stack analyzer reading
3. Adjust the air registers to get the
correct
c. balance with the process flow rates
12. (True/False) A process technician completes the inspection of the furnace’s
internal components.
13. (True/False) When using combination burners, firebox temperature must be
near the operating range before the fuel oil is introduced.
Process Technology Equipment
Chapter 13 Furnaces
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14. What is required for the decoking procedure? (Select all that apply.)
a. Air
b. Water
c. Steam
d. Bleach
