Process Technology Equipment Chapter 7 Compressors
Page 1
CHAPTER 7 Compressors
Table of Contents
Contents
Page
Chapter Overview
2
Class Preparation Checklist
2
Chapter Objectives
2
Agenda
4
Lesson Plan
6
7.0 Selection of Compressors
7.1 Types of Compressors
7
8
7.2 Centrifugal Compressor Performance Curve
13
7.3 Associated Utilities and Auxiliary Equipment
7.4 Potential Problems
7.5 Safety and Environmental Hazards
7.6 Process Technician’s Role in Operations and
Maintenance
7.7 Typical Procedures
13
16
19
20
20
Summary and Wrap-Up
21
Suggested Student Activities
22
End of Chapter Review Questions
22
Clicker Questions
Appendix
34
37
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CHAPTER 7 Compressors
Chapter Overview
Compressors are an important part of the process industries. Compressors are devices
that transport gases and vapors from one place to another and increase their pressure
for use in applications that require higher pressures. For example, they can be used to
compress gases such as carbon dioxide, nitrogen, and light hydrocarbons, or they can
provide the compressed air required to operate instruments or equipment.
The difference between the operation of compressors and the operation of pumps has
to do with the physical properties of gases and liquids. While they operate similarly,
compressors are not designed to move liquids, and pumps are not designed to move
gases.
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
5.
Review the PowerPoint slides associated with this chapter (if used) and
make sure that your computer is correctly set up to navigate the slide deck
smoothly.
6.
Request the appropriate A/V equipment (if needed) and make sure that
your computer is correctly synched with the projector to avoid any delays in
the classroom.
Chapter Objectives
7.1 Describe the purpose of compressors, their common types, and operating principles
of each (NAPTA Compressors).
7.2 Explain the purpose of a compressor performance curve and demonstrate its use
(NAPTA Compressors).
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7.3 Identify compressor components and auxiliaries and explain the purpose of each
(NAPTA Compressors).
7.4 Identify potential problems associated with compressors (NAPTA Compressors).
7.5 Describe safety and environmental concerns associated with compressors (NAPTA
Compressors).
7.6 Describe the process technician’s role in compressor operation and maintenance
(NAPTA Compressors).
7.7 Identify typical procedures associated with compressors (NAPTA Compressors).
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Class Agenda
Activity
Minutes
PPTs
Handouts
(title, if
any)
1. Welcome to Class
1
2. Introduction and Agenda
2
3. Safety Minute
3
4. Objectives
4
5. Objectives (cont.)
5
6. Terms
6
7. Selection of Compressors
7
8. Types of Compressors
8
9. Dynamic Compressors
9
10. Centrifugal Compressors
10
11. Axial Compressors
11
12. Compression Ratio
12
13. Positive Displacement Compressor
13
14. Reciprocating Compressor
14
15. Rotary Compressors
15
16. Rotary Compressors (cont.)
16
17. Single-Stage Versus Multistage Compressors
17
18. Centrifugal Compressor Performance Curve
18
19. Associated Utilities and Auxiliary Equipment
19
20. Lubrication Systems
20
21. Seal Systems
21
22. Antisurge Devices
22
23. Coolers
23
24. Separators
24
25. Potential Problems
25
26. Overpressurization
26
27. Overheating
27
28. Surging
28
29. Seal Oil Problems
29
30. Leaks
30
31. Lubrication Fluid Contamination
31
32. Vibration
32
33. Interlock Systems
33
34. Loss of Capacity
34
35. Motor Overload
35
36. High/Low Flow
36
37. Safety and Environmental Hazards
37
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38. Process Technician’s Role in Operations and
Maintenance
38
39. Typical Procedures
39
40. Start-Up and Shutdown
40
41. Lockout/Tagout
41
42. Emergency Procedures
42
43. Summary and Wrap-Up
43
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Chapter 7 Lesson Plan
Welcome Everyone to Class
Time: 1 minute
Resources: Slide 1
Introduction and Agenda
Time: 1.5 minutes
Resources: Slide 2
Sample Instructor Script:
Compressors are an important part of the process industries. Compressors are devices
that transport gases and vapors from one place to another and increase their pressure
for use in applications that require higher pressures.
Student Safety Minute
Time: 2 minutes
Resources: Slide 3
(Note to Instructor: Follow this procedure for the Safety Minute.)
Objectives
Time: 0.5 minute
Resources: Slide 4
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Sample Instructor Script:
Additionally, process technicians should demonstrate an ability to identify potential
compressor problems.
Objectives (cont.)
Time: 0.5 minute
Resources: Slide 5
Terms
Time: 3 minutes
Resources: Slide 6
7.0 Selection of Compressors
Time: 0.5 minute
Resources: Slide 7
7.1 Types of Compressors
Time: 1 minute
Resources: Slide 8
Sample Instructor Script:
7.1.1 Dynamic Compressors
Time: 0.5 minute
Resources: Slide 9
7.1.2 Centrifugal Compressors
Time: 2 minutes
Resources: Slide 10
Sample Instructor Script:
One type of dynamic compressor is the centrifugal compressor. In this type of
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Centrifugal compressors are used throughout industry because they have few moving
parts, are very energy efficient, and provide higher flow rates than similarly sized
reciprocating compressors.
Centrifugal compressors are also popular for the following reasons:
7.1.3 Axial Compressors
Time: 2 minutes
Resources: Slide 11
Each pair of rotors and stators is referred to as a stage. Most axial compressors have a
number of such stages placed in a row along a common power shaft in the center. Each
stage is smaller than the last because the volume of gas is reduced by the compression
of the preceding stage.
This is the reason axial compressors generally have a conical shape, widest at the inlet
and narrowest at the outlet. This compressor type typically has between nine and fifteen
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stages. The main components of an axial compressor include the housing (casing), inlet
and outlet, rotor and stator blades, shaft, and inlet guide vanes.
7.1.4 Compression Ratio
Time: 1 minute
Resources: Slide 12
Sample Instructor Script:
7.1.5 Positive Displacement Compressors
Time: 1 minute
Resources: Slide 13
7.1.6 Reciprocating Compressors
Time: 2 minutes
Resources: Slide 14
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Sample Instructor Script:
The term reciprocating refers to the back–and–forth movement of a compression device
industrial applications. Common applications for the reciprocating compressor include
instrument air systems and compression of flammable gases.
In a piston–type reciprocating compressor, a piston receives force from a power
medium (for example, a drive shaft) and then transfers that power to the gas being
compressed. The gas is trapped between the piston and the cylinder head and then
compressed. The cylinder is the chamber in which a piston compresses gas and from
which gas is expelled.
7.1.7 Rotary Compressors
Time: 1.5 minutes
Resources: Slide 15
Sample Instructor Script:
Rotary compressors move gases by turning a set of screws, lobes, or vanes. As these
screws, lobes, or vanes rotate, gas is drawn into the spaces between these components
and moves through the compressor until being forced out of the compressor through the
discharge.
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from a constant suction pressure, they maintain a more constant discharge pressure
than piston compressors do.
In a rotary screw compressor, two helical (spiral) rotors (sometimes called screws)
mesh together as they turn and move a gas or vapor from the suction to the discharge
end. While the two rotors do not contact each other, the space between them is very
7.1.8 Rotary Compressors (cont.)
Time: 1 minute
Resources: Slide 16
Sample Instructor Script:
7.1.9 Single–Stage versus Multistage Compressors
Time: 1 minute
Resources: Slide 17
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7.3.1 Lubrication Systems
Time: 0.5 minute
Resources: Slide 20
Sample Instructor Script:
7.3.2 Seal Systems
Time: 2 minutes
Resources: Slide 21
Sample Instructor Script:
7.3.3 Antisurge Devices
Time: 1 minute
Process Technology Equipment Chapter 7 Compressors
Resources: Slide 22
7.3.4 Coolers
Time: 0.5 minute
Resources: Slide 23
7.3.5 Separators
Time: 1 minute
Resources: Slide 24
Sample Instructor Script:
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7.4 Potential Problems
Time: 1 minute
Resources: Slide 25
7.4.1 Overpressurization
Time: 1 minute
Resources: Slide 26
7.4.2 Overheating
Time: 1 minute
Resources: Slide 27
7.4.3 Surging
Time: 1 minute
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Resources: Slide 28
7.4.4 Seal Oil Problems
Time: 1 minute
7.4.5 Leaks
Time: 1 minute
Resources: Slide 30
7.4.6 Lubrication Fluid Contamination
Time: 1 minute
Resources: Slide 31
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7.4.7 Vibration
Time: 1 minute
Resources: Slide 32
7.4.8 Interlock Systems
Time: 1 minute
Resources: Slide 33
Sample Instructor Script:
7.4.9 Loss of Capacity
Time: 1 minute
Resources: Slide 34
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7.4.10 Motor Overload
Time: 1 minute
Resources: Slide 35
7.4.11 High/Low Flow
Time: 1 minute
Resources: Slide 36
Sample Instructor Script:
Lubricant flow that is too high or too low may indicate imminent bearing or seal failure.
Because of this, lubricant flow monitoring systems are designed to activate an alarm
should flow that is too high or too low be detected.
Excessive gas flow through the compressor may result from a compressor operating at
excessive RPM, which could result in compressor damage.
Additionally, a gas flow that is too low through the compressor may indicate suction–side
restrictions or the onset of compressor surge conditions.
7.5 Safety and Environmental Hazards
Page 20
Time: 0.5 minute
Resources: Slide 37
Sample Instructor Script:
Hazards associated with normal and abnormal compressor operations can affect
personal safety, equipment, and the environment. Personal safety hazards include:
• Excessive noise levels
• Slipping/tripping due to leaks
• Chemical exposures
• Skin burns
7.6 Process Technician’s Role in Operations and Maintenance
Time: 1 minute
Resources: Slide 38
Sample Instructor Script:
7.7 Typical Procedures
Time: 0.5 minute
Resources: Slide 39
7.7.1 Start–up and Shutdown