Process Technology Equipment Chapter 7 Compressors
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Time: 1 minute
Resources: Slide 40
Sample Instructor Script:
Start–up and shutdown procedures vary considerably, depending on the type of
compressor driver and compressor. While some machines start under no–load or low–
load conditions by opening the recycle valves and establishing minimum flow, others
start with both suction and discharge valves wide open.
The process technician must recognize the importance of understanding and following
specific start–up and shutdown procedures for all equipment.
7.7.2 Lockout/Tagout
Time: 1 minute
Resources: Slide 41
Sample Instructor Script:
Lockout/tagout procedures may differ from facility to facility, but the purpose is the
7.7.3 Emergency Procedures
Time: 1 minute
Resources: Slide 42
Summary and Wrap–Up
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1. Given a cutaway or diagram of a reciprocating compressor, identify the following
components:
2. Using a P&ID provided by your instructor, locate and identify the compressors.
3. Using a P&ID provided by your instructor, locate the compressors. Prepare a
4. In teams, using a P&ID provided by your instructor, design an antisurge device to
improve the existing system shown on the P&ID or draw a diagram of an antisurge
device for a compressor system. Have each team present the design to the class and
explain its benefits.
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.)
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1. Which of the following should be considered when selecting a type of
compressor?
A. Flow rate
B. Suction pressure
C. Type of liquid being compressed
D. All of the above
2. How is discharge pressure expressed?
A. Kilopascals (kPa)
B. Milliliters per second (mps)
C. Cubed per second (m3/s)
D. Cubic feet per minute (cfm)
3. Why are dynamic compressors more commonly used than positive
displacement compressors?
A. They are more efficient.
Process Technology Equipment Chapter 7 Compressors
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B. Less energy is required.
C. They have a smaller capacity.
D. They require no maintenance.
4. What dynamic compressors have a flow of gas that is parallel to the shaft?
A. Axial compressors
B. Rotary compressors
C. Centrifugal compressors
D. Reciprocating compressors
5. What type of compressor would you use if you needed to power aircraft?
A. Axial compressor
Process Technology Equipment Chapter 7 Compressors
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B. Centrifugal compressor
C. Rotary compressor
D. Reciprocating compressor
6. What compressors move gases by turning a set of screws, lobes, or vanes?
A. Axial compressors
B. Rotary compressors
C. Centrifugal compressors
D. Reciprocating compressors
7. What type of compressor would you use in an instrument air system?
A. Axial compressor
B. Centrifugal compressor
C. Rotary compressor
D. Reciprocating compressor
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8. What is the compression ratio of a compressor with a suction pressure of 400
psiA and a discharge pressure of 1600 psiA?
A. 2
B. 3
C. 4
D. 5
9. What happens when the compressor discharge pressure falls below the
pressure in the discharge line?
A. Forward flow stops and gas from the discharge line flows backward.
B. Forward flow increases and overcomes the line pressure.
C. Upstream line pressure drops as well as the process temperature.
D. The compressor will make loud noises.
Answers:
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10. What process data is collected from a compressor?
A. Suction rate
B. Temperature
C. Intercooler pressure
D. All of the above
11. What auxiliary system prevents process gases from leaking to the atmosphere
where the compressor shaft exits the casing?
A. Seal system
B. Separators
C. Lubrication system
D. Coolers
Process Technology Equipment Chapter 7 Compressors
12. What type of seal is a close-fitting bushing in which a liquid is injected in
order to seal the process from the atmosphere?
A. Packing
B. Dry carbon rings
C. Liquid buffered seal
D. Labyrinth seal
13. What type of seal is a low-leakage type of seal that can be arranged with a
buffer gas that separates the process gas from the atmosphere?
A. Packing
B. Dry carbon rings
C. Liquid buffered seal
D. Labyrinth seal
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18. Which of the following is a personal safety hazard associated with
compressors?
A. High pressure
B. High temperatures
C. Slipping due to leaks
D. All of the above
19. Which of the following is an equipment hazard associated with compressors?
A. Inadequate lubrication
B. Cold working conditions
C. Exposure to hazardous materials
D. All of the above
20. Which of the following is an environmental hazard associated with
compressors?
A. Seal leaks
B. Electric shock
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C. Excessive noise levels
D. High-voltage electricity
21. Which of the following is a mechanical problem that process technicians
should check for in rotating equipment?
A. Excess lubrication
B. Seal leakage
C. Low vibration
D. All of the above
22. Which of the following should process technicians look for in the operation
and maintenance of compressors?
A. Oil levels
B. Flow rates
C. Liquid levels
D. All of the above