Process Technology Equipment
Chapter 13 Furnaces
Page 1
CHAPTER 13 Furnaces
Table of Contents
Contents
Page
Chapter Overview
2
Class Preparation Checklist
2
Chapter Objectives
2
Agenda
3
Lesson Plan
4
13.0 Furnaces
13.1 Furnace Types and Applications
6
6
13.2 Furnace Sections and Components
8
13.3 Furnace Operating Principles
13.4 Potential Problems
13.5 Safety and Environmental Hazards
13.6 Process Technician’s Role in Operation and
Maintenance
13.7 Typical Procedures
10
12
15
17
18
Summary and Wrap-Up
18
Suggested Student Activities
19
End of Chapter Review Questions
Clicker Questions
19
29
Appendix
32
Process Technology Equipment
Chapter 13 Furnaces
Page 2
CHAPTER 13 Furnaces
Chapter Overview
In the process industries, heat exchangers transfer (exchange) heat from one
substance to another without the two materials physically contacting each other. Heat
exchangers come in a variety of types, with the most common type being the shell-and-
tube exchanger.
The process technician is responsible for understanding the purpose, components, and
safe operation of heat exchangers. While the heat exchanger is not a complicated piece
of equipment, problems do occur, and the process technician must know how to
address them. Since heat exchangers contain hot liquids and a heating medium, it is
essential that the process technician understand and adhere to all related operating and
safety procedures.
Class Preparation Checklist
1.
Familiarize yourself with the chapter content.
2.
Bring cutaways or other hands-on teaching aids if available.
3.
Copy and distribute any fill-in-the-blank handouts for today’s content.
4.
Safety Minute prepared or assigned
Chapter Objectives
13.1 Identify the purpose, common types, and applications of furnaces (NAPTA
Furnaces).
13.2 Identify the components of furnaces and the purpose of each (NAPTA Furnaces).
13.3 Explain the operating principles of furnaces (NAPTA Furnaces).
13.4 Identify potential problems associated with furnaces (NAPTA Furnaces).
13.5 Describe safety and environmental hazards associated with furnaces (including
stack and emissions controls) (NAPTA Furnaces).
13.7 Identify typical procedures associated with furnaces (NAPTA Furnaces).
Process Technology Equipment
Chapter 13 Furnaces
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Class Agenda
Activity
Minutes
PPTs
1. Welcome to Class
1
1
2. Introduction and Agenda
1
2
3. Safety Minute
2
3
4. Objectives
0.5
4
5. Objectives (cont.)
0.5
5
6. Terms
1.5
6
7. Terms (cont.)
1.5
7
8. Furnaces
0.5
8
9. Furnace Types and Applications
1
9
10. Common Furnace Designs
1
10
11. Furnace Draft Types
3
11
12. Furnace Sections and Components
0.5
12
13. Radiant Section
4
13
14. Convection Section
3
14
15. Furnace Operating Principles
0.5
15
16. Fuel Supply
0.5
16
17. Combustion Air
1
17
18. Flame Temperature
1
18
19. Furnace Pressure Control
1
19
20. Interlock Systems
1
20
21. Potential Problems
2
21
22. Equipment Age and Design
1
22
23. Instrument Problems
0.5
23
24. Fouling
1
24
25. Tube Life and Temperature
1
25
26. External Factors
0.5
26
27. Insufficient Maintenance
2
27
28. Safety and Environmental Hazards
0.5
28
29. Fires, Spills, and Explosions
2
29
30. Hazardous Operating Conditions
2
30
31. Personal Safety with Furnaces
1
31
32. Environmental Impact
3
32
33. Process Technician’s Role in Furnace
Operations and Maintenance
2
33
34. Typical Procedures
0.5
34
35. Furnace Start-up and Shutdown
1
35
36. Summary and Wrap-Up
4
36
Process Technology Equipment
Chapter 13 Furnaces
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Chapter 13 Lesson Plan
Welcome Everyone to Class
Time: 1 minute
Resources: Slide 1
Introduction and Agenda
Time: 1 minute
Resources: Slide 2
Safety Minute
Time: 2 minutes
Resources: Slide 3
(Note to Instructor: Follow this procedure for the Safety Minute.)
• Announce who has responsibility for today’s Safety Minute.
• Have the student present the Safety Minute.
• Announce who is presenting the Safety Minute next class.
Objectives
Time: 0.5 minute
Resources: Slide 4
Process Technology Equipment
Chapter 13 Furnaces
Objectives (cont.)
Time: 0.5 minute
Resources: Slide 5
Terms
Time: 1.5 minutes
Resources: Slide 6
Sample Instructor Script:
Turn to the terms page in today’s chapter in the textbook. I’ll call on some of you to take
turns reading the term and definition aloud and then using that term in a sentence:
Terms (cont.)
Time: 1.5 minutes
Resources: Slide 7
Sample Instructor Script:
More terms related to furnaces include:
Process Technology Equipment
Chapter 13 Furnaces
Process Technology Equipment
Chapter 13 Furnaces
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13.1.1 Common Furnace Designs
Time: 1 minute
Resources: Slide 10
Sample Instructor Script:
13.1.2 Furnace Draft Types
Time: 3 minutes
Resources: Slide 11
Sample Instructor Script:
Like cooling towers, airflow (called draft) inside furnaces can be provided by natural air
currents (natural draft) or mechanical air currents (assisted draft).
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Chapter 13 Furnaces
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Forced draft pushes air into the furnace. A balanced draft has fans that both force and
induce air movement.
Time: 0.5 minute
Resources: Slide 12
13.2.1 Radiant Section
Time: 4 minutes
Resources: Slide 13
Sample Instructor Script:
The radiant section, located at the bottom of the furnace, is closest to the heat source
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Chapter 13 Furnaces
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The heat that is produced by the burners radiates into the main body of the furnace,
called the firebox. Because so much heat is generated in this section, the firebox must
be lined with a special refractory lining to protect the furnace structure.
The tubes located along the walls of the radiant section are called radiant tubes
because they receive radiant heat from the furnace burners. The tubes can be mounted
either vertically or horizontally, and are placed in different locations or arrangements
depending on the type of furnace.
To protect the outside metal walls of the furnace from excessive heat, a refractory
13.2.2 Convection Section
Time: 3 minutes
Resources: Slide 14
Sample Instructor Script:
As the heat moves up through the furnace, it eventually leaves the radiant section and
moves into the convection section located at the top of the furnace firebox and farther
away from the heat source.
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Chapter 13 Furnaces
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If a boiler is a part of the furnace operation, the boiler feedwater is preheated here as
well. It is considered the cooler section of the furnace. Within this section are convection
tubes, and above this section are the stack and damper.
At the top of the furnace is the stack, a cylindrical outlet that removes flue gas from the
furnace. Within the stack is a valve or movable plate called the stack damper. The
damper regulates the flow of air (draft) and flue gases leaving a furnace.
13.3 Furnace Operating Principles
Time: 0.5 minute
Resources: Slide 15
13.3.1 Fuel Supply
Time: 0.5 minute
Resources: Slide 16
Sample Instructor Script:
Temperatures inside the furnace system determine the fuel supply flow. In many
process furnaces, the temperature of the stack gas and the product analysis exiting the
tubes indicate how much fuel is needed.
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Chapter 13 Furnaces
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13.3.2 Combustion Air
Time: 1 minute
Resources: Slide 17
Sample Instructor Script:
13.3.3 Flame Temperature
Time: 1 minute
Resources: Slide 18
13.3.4 Furnace Pressure Control
Time: 1 minute
Resources: Slide 19
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Chapter 13 Furnaces
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13.3.5 Interlock Systems
Time: 1 minute
Resources: Slide 20
Sample Instructor Script:
13.4 Potential Problems
Time: 2 minutes
Resources: Slide 21
Sample Instructor Script:
When operating furnaces, process technicians must be aware of certain situations that
can result in system shutdown or off–specification product. Some of the problems
encountered include:
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Chapter 13 Furnaces
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13.4.1 Equipment Age and Design
Time: 1 minute
Resources: Slide 22
Sample Instructor Script:
13.4.2 Instrument Problems
Time: 0.5 minute
Resources: Slide 23
13.4.3 Fouling
Time: 1 minute
Resources: Slide 24
Sample Instructor Script:
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13.4.4 Tube Life and Temperature
Time: 1 minute
Resources: Slide 25
Sample Instructor Script:
Time: 0.5 minute
Resources: Slide 26
13.4.6 Insufficient Maintenance
Time: 2 minutes
Resources: Slide 27
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13.5 Safety and Environmental Hazards
Time: 0.5 minutes
Resources: Slide 28
13.5.1 Fires, Spills, and Explosions
Time: 2 minutes
Resources: Slide 29
Sample Instructor Script:
Process furnaces usually contain combustible gases and liquids under pressure, so
there is always the potential for uncontrolled fires, spills, or explosions. For example,
tube failures can cause significant and sudden fires.
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Chapter 13 Furnaces
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13.5.2 Hazardous Operating Conditions
Time: 2 minutes
Resources: Slide 30
Sample Instructor Script:
Hazards are present during both normal and abnormal furnace operations. Examples
include the following:
13.5.3 Personal Safety with Furnaces
Time: 1 minute
Resources: Slide 31
Sample Instructor Script:
In addition to wearing standard personal protective equipment, process technicians
should observe the following precautions when performing routine preventive
maintenance on furnace equipment:
Process Technology Equipment
Chapter 13 Furnaces
13.5.4 Environmental Impact
Time: 3 minutes
Resources: Slide 32
Sample Instructor Script:
It is essential for furnaces to operate correctly because excessive smoke, SOx (sulfur
oxide), CO (carbon monoxide), or NOx (nitrogen oxide) emissions from furnace
operations can have a negative impact on the environment and can result in citations or
fines.
In addition to creating a hazard in the firebox, smoke emissions result in violations.
Smoking is caused by incomplete combustion of fuels. Understanding and controlling
burner operations can provide the right balance for complete combustion and control of
smoke emissions.
13.6 Process Technician’s Role in Furnace Operations and Maintenance
Time: 2 minutes
Resources: Slide 33
Sample Instructor Script:
Furnace operations have a direct and immediate impact on the operation of other
Process Technology Equipment
Chapter 13 Furnaces
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Chapter 13 Furnaces
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Sample Instructor Script:
Let’s summarize today’s lesson and consider what we will be doing in the next class.
Suggested Student Activities
(Note to Instructor: Time permitting, do the activities listed below or possibly assign
them as homework. Be sure to remind students what to read for the next class.)
1. Given a diagram or a cutaway of a furnace, identify the various components and
explain the purpose of each.
3. Complete a one-page report on one of the following:
a) Nitrous oxide (NOx)
b) Carbon monoxide (CO)
c) Carbon dioxide (CO2)
4. Use the internet or other research mechanism to identify the type of feedstock that
would be used in each type of furnace listed here:
a) Box type
b) Cylindrical type
c) Cabin type
End of Chapter Review Questions
(Note to Instructor: If you have time, you can use these questions to test your
students’ knowledge of the content presented in this chapter.)