Operator's Guide to Process Compressors

The perfect primer for anyone responsible for operating or maintaining process gas compressors.

Gas compressors tend to be the largest, most costly, and most critical machines employed in chemical and gas transfer processes. Since they tend to have the greatest effect on the reliability of processes they power, compressors typically receive the most scrutiny of all the machinery among the general population of processing equipment. To prevent unwanted compressor failures from occurring, operators must be taught how their equipment should operate and how each installation is different from one another.

The ultimate purpose of this book is to teach those who work in process settings more about gas compressors, so they can start up and operate them correctly and monitor their condition with more confidence. Some may regard compressor technology as too broad and complex a topic for operating personnel to fully understand, but the author has distilled this vast body of knowledge into some key, easy to understand lessons for the reader to study at his or her own pace.

This groundbreaking new work is a must-have for any engineer, operator, or manager working with process compressors.

The main goals of this book are to:

• Explain important theories and concepts about gases and compression processes with a minimum of mathematics

• Identify key compressor components and explain how they affect reliability

• Explain how centrifugal compressors, reciprocating compressors, and screw compressors function.

• Explain key operating factors that affect reliabilityIntroduce the reader to basic troubleshooting methodologies

• Introduce operators to proven field inspection techniques

• Improve the confidence of personnel operating compressors by teaching them the basics of compressor theory

• Improve compressor reliability plantwide by teaching operating and inspection best practices

• Improve communication between operating and supporting plant personnel by providing a common vocabulary of compressor terms

• Help processing plants avoid costly failures by teaching operators how to identify early compressor issues during field inspections

Autorentext

Robert X. Perez is mechanical engineer with more than 40 years of rotating equipment experience in the petrochemical industry. He has worked in petroleum refineries, chemical facilities, and gas processing plants. Currently, he provides engineering consulting services and rotating equipment training. He earned a BSME degree from Texas A&M University at College Station, an MSME degree from the University of Texas at Austin and holds a Texas PE license. Mr. Perez has written numerous machinery reliability articles for magazines and conferences proceedings and has authored 4 books and coauthored 4 books related to machinery reliability. He resides in San Antonio, Texas.

Inhalt
Preface xv

1 Introduction to Gases 1

1.1 Ideal Gases 4

1.2 Properties of Gases 5

1.3 Temperature 5

1.4 Pressure 6

1.5 Gas Laws 7

1.6 Gas Mixtures 10

1.6.1 Dalton's Law of Partial Pressures 10

1.7 Molecular Weight of a Gas Mixture 11

1.8 Gas Density 13

1.9 Density of Mixtures 14

1.10 Heat of Compression 15

2 Commonly Used Compressor Flow Terms 19

2.1 Ideal Gas Law 20

2.1.1 Example of How to Convert from SCFM to ACFM 22

2.2 Visualizing Gas Flow 23

2.3 Compressibility Factor (Z) 25

2.4 Sizing Compressors 27

3 Compression Processes 31

3.1 Adiabatic Compression 33

3.2 Polytropic Compression 37

3.2.1 Polytropic Example #1 40

3.2.2 Polytropic Example 2 40

4 What Role the Compression Ratio Plays in Compressor Design and Selection 43

4.1 Compression Ratio versus Discharge Temperature 44

4.2 Design Temperature Margin 46

4.2.1 Design Trade-Offs 49

5 An Introduction to Compressor Operations 53

5.1 Compression Basics 53

5.2 Defining Gas Flow 55

5.3 Compressor Types 56

5.4 Multistaging 59

5.5 Key Reliability Indicators 60

6 Centrifugal Compressors 63

6.1 Centrifugal Compressor Piping Arrangements 66

6.2 Start-Up Configuration 68

6.3 Centrifugal Compressor Horsepower 68

6.4 Troubleshooting Tips 70

6.5 Centrifugal Compressor Start-Ups 71

6.6 Centrifugal Compressor Checklist 72

7 How Process Changes Affect Centrifugal Compressor Performance 75

7.1 Baseball Pitcher Analogy 75

7.2 How Gas Density Affects Horsepower 78

7.3 Theory versus Practice 80

8 How to Read a Centrifugal Compressor Performance Map 83

8.1 The Anatomy of a Compressor Map 85

8.1.1 Flow Axis (See Figures 8.2 and 8.3) 85

8.1.2 Head or Pressure Ratio Axis (See Figures 8.2 and 8.3) 86

8.1.3 Predicted Surge Line (See Figures 8.2 and 8.3) 86

8.1.4 Predicted Capacity Limit (Figures 8.2 and 8.3) 86

8.1.5 Surge Margin (See Figure 8.2) 87

8.1.6 Speed Lines (See Figures 8.2 and 8.3) 88

8.2 Design Conditions 88

9 Keeping Your Centrifugal Compressor Out of Harm's Way 91

9.1 Compressor Operating Limits 93

9.2 Compressor Flow Limits 93

9.3 Critical Speeds 95

9.4 Horsepower Limits 96

9.5 Temperatures 97

10 Troubleshooting Centrifugal Compressors in Process Services 101

10.1 The Field Troubleshooting ProcessStep by Step 105

10.1.1 Step 1: Define the Problem 105

10.1.2 Step 2: Collect All Pertinent Data 105

10.1.3 Step 3: Analyze the Body of Data as a Whole 106

10.1.4 Step 4: Act and Confirm 106

10.2 The Hourglass Approach to Troubleshooting 108

10.3 Thinking and Acting Globally 109

10.4 Troubleshooting Matrix and Table 110

10.5 Centrifugal Compressor Troubleshooting Example 110

11 Reciprocating Compressors 117

11.1 Reciprocating Compressor Installations 124

11.1.1 How Process Conditions Affect Reciprocating Compressor Performance 126

11.2 Reciprocating Compressor Start-Ups 128

11.3 Reciprocating Compressor Checklist 129

11.4 Criticality 131

12 Troubleshooting Reciprocating Compressors in Process Services 133

12.1 The Field Troubleshooting ProcessStep by Step 137

12.1.1 Step 1: Define the Problem 137

12.1.2 Step 2: Collect All Pertinent Data 137

12.1.3 Step 3: Analyze the Body of Data as a Whole 138

12.1.4 Step 4: Act and Confirm 138

12.1.5 Troubleshooting Matrix and Table 140 12.1.6 Recipr...