Packaged, Integrally Geared Centrifugal Air Compressors for Petroleum, Chemical, and Gas Industry Services

API STANDARD 672

FIFTH EDITION, AUGUST 2019

Special Notes

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Copyright © 2019 American Petroleum Institute

Foreword

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Shall: As used in a standard, “shall” denotes a minimum requirement in order to conform to the standard.

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Suggested revisions are invited and should be submitted to the Standards Department, API, 200 Massachusetts Avenue, NW, Suite 1100, Washington, DC 20001, standards@api.org.

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1. Scope 1

2. Normative References. 1

3. Terms, Definitions, Acronyms, and Abbreviations 4

   1. Terms and definitions 4

   2. Acronyms and Abbreviations 10

4. General 12

   1. Unit Responsibility 12

   2. Nomenclature 12

5. Requirements 12

   1. Units of measurement 12

   2. Statutory Requirements 12

   3. Document Requirements 13

6. Basic Design 13

   1. General 13

   2. Pressure Casings 18

   3. Casing Connections 18

   4. External Forces and Moments 19

   5. Rotating Elements 20

   6. Seals and Sealing Systems 21

   7. Dynamics 21

   8. Bearings and Bearing Housings 23

   9. Lubrication 24

   10. Materials 25

   11. Nameplates and Rotation Arrows 27

   12. Additional Basic Design Requirements for Special Duty Packages Only 28

7. Accessories 30

   1. Drivers 30

   2. Couplings and Guards 31

   3. Baseplate/Support Structure 33

   4. Controls and Instrumentation 34

   5. Piping 41

   6. Intercoolers and Aftercoolers 42

   7. Inlet Air Filter 43

   8. Discharge Blowoff Silencer 43

   9. Special Tools 43

   10. Additional Accessories Requirements for “Special Duty”Packages Only 44

8. Inspection, Testing, and Preparation for Shipment 45

   1. General 45

   2. Inspection 46

   3. Testing 46

   4. Preparation for Shipment 49

   5. Additional Inspection, Testing, and Preparation for Shipment Requirements for “Special Duty” Packages Only 50

9. Vendor’s Data 51

   1. General 51

Annex A (informative) Typical Datasheets 52

Annex B (informative) Illustrations of Typical Package Mounting Configurations 65

Annex C (normative) Dynamics 68

Annex D (informative) Contract Documents and Engineering Design Data 84

Annex E (informative) Compressor Control—Inlet Throttle Butterfly 96

Annex F (normative) Determination of Residual Imbalance 97

Annex G (normative) Inspector’s Checklist 105

Annex H (informative) Nomenclature for Integrally Geared Centrifugal Air Compressors 108

Annex I (normative) External Forces and Moments 113

Bibliography 114

Figures

A.1 Typical Datasheets for Centrifugal Air Compressors 53

1. Package with Full Drain-rim Base 65

2. Package with Open-channel Structural Base 65

3. Package with Foot Mounted Base. 66

4. Package with Base Integral with Casing 66

5. Package with Split Base (Separate Exchanger Skid) 67

6. Package with Three-point Spherical Bearings Supports 67

1. Undamped Critical Speed Map 69

2. Mode Shapes 71

3. Unbalance Placement and Mode Shapes for Overhung Machines 72

4. Typical Rotor Response Plot 73

5. Plot of Applicable Speed Range of Vibration Limit 74

6. Level 1 Stability Sensitivity Plot 79

7. Stability Experience Plot 79

1. VDDR for Packaged, Integrally Geared Centrifugal Air Compressors 89

2. Description of VDDR 91

E.1 Typical Performance Curve Showing BFV vs IGV Control 96

1. (Blank) Residual Unbalance Work Sheet 99

2. (Blank) Residual Unbalance Polar Plot Work Sheet 100

3. Sample Residual Unbalance Work Sheet for Left Plane 101

4. Sample Residual Unbalance Polar Plot Work Sheet for Left Plane 102

5. Sample Residual Unbalance Work Sheet for Right Plane 103

6. Sample Residual Unbalance Polar Plot Work Sheet for Right Plan 104

G.1 Inspector’s Checklist 105

1. Section of Axially (horizontally) Split Compressor 108

2. Section of Radially Split Compressor 109

3. Nomenclature of Package Components, Part 1 110

4. Nomenclature of Package Components, Part 2 111

5. Nomenclature of Package Components, Part 3 112

Tables

1 Equipment Monitoring 39

1. VDDR for Packaged, Integrally Geared Centrifugal Air Compressors 90

2. VDDR for Packaged, Integrally Geared Centrifugal Air Compressors 92

1. Inspector’s Checklist 106

   
   

   Introduction

   
   

   Users of this standard should be aware that further or differing requirements may be needed for individual applications. This standard is not intended to inhibit a vendor from offering, or the purchaser from accepting, alternative equipment or engineering solutions for the individual application. This may be particularly appropriate where there is innovative or developing technology. Where an alternative is offered, the vendor should identify any variations from this standard and provide details.

   
   

   Annex A contains data sheets which purchasers are encouraged to use. Annex B contains illustrations of typical mounting configurations.

   Annex C specifies requirements for lateral analysis.

   
   

   Annex D contains forms which may be used to indicate vendor drawing and data requirements. Annex E shows the impact for inlet throttle control vs inlet guide vanes.

   Annex F specifies requirements for determining residual unbalance. Annex G contains an inspector’s checklist.

   Annex H contains illustrations of nomenclature for integrally geared centrifugal air compressors. Annex I contains information relative to allowable nozzle loads from purchaser’s piping.

   This standard requires the purchaser to specify certain details and features. A bullet () at the beginning of a paragraph indicates that either a decision by, or further information from, the purchaser is required. Further information should be shown on the data sheets (see example in Annex A) or stated in the quotation request and purchase order.

   
   

   In this standard, U.S. customary units (USC) are included in brackets for information.

   
   

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   Packaged, Integrally Geared Centrifugal Air Compressors for Petroleum, Chemical, and Gas Industry Services

   
   

   1. Scope

      1.1 This standard covers the minimum requirements for constant-speed, packaged, general purpose, integrally- geared centrifugal air compressors, including their accessories for use in the petroleum, chemical, and gas industry services. This standard is not applicable to machines that develop a pressure rise of less than 0.35 bar (5.0 psi) above atmospheric pressure, which are classed as fans or blowers.

      
      

      NOTE Special purpose and process applications, including Process Air Services, are covered by API 617.

      
      

      • 1.2 Equipment covered by this standard is considered non-critical, usually spared and may be either of two classifications, basic or special duty. The purchaser shall specify which of the two classifications applies.

      
      

      Basic packages are vendors’ standard packages of proven design, and include minimal additional requirements.

      
      

      Special duty packages are typically specified for installations that require higher availability, and include additional features and requirements.

      
      

      1.3 Additional or overriding requirements applicable only to packages that have been specified as “Special Duty” are noted at the end of each section (see 6.12, 7.10, 8.5, D.2.5, and D.3.5.5).

      
      

   2. Normative References

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) available at the agreed time, applies. Standards referenced in the documents are undated but refer to the specific editions referenced in this section.

ANSI/API Standard 541, Form-Wound Squirrel Cage Induction Motors—500 Horsepower and Larger

ANSI/API Standard 546, Brushless Synchronous Machines—500 kVA and Larger

API Standard 547, General-purpose Form-wound Squirrel Cage Induction Motors 250 Horsepower and Larger

API Standard 611, General-purpose Steam Turbines for Petroleum, Chemical, and Gas Industry Services

API Standard 614, Lubrication, Shaft-sealing, and Control-oil Systems and Auxiliaries for Petroleum, Chemical and Gas Industry Services

ANSI/API Standard 670, Machinery Protection Systems

AGMA 6011 1, Specification for High Speed Helical Gear Units

AGMA 9000-C90, Flexible Couplings—Potential Unbalance Classification AGMA 9002-B04, Bores and Keyways for Flexible Couplings (Inch Series) ASME B1.1 2, Unified Inch Screw Threads (UN and UNR Thread Form)

1. American Gear Manufacturers Association, 1001 N. Fairfax Street, Suite 500, Alexandria, Virginia, 22314, www.agma.org.

2. ASME International, 2 Park Avenue, New York, New York 10016-5990, www.asme.org.

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