Anthony J. Smalley P. Joe Pantermuehl. Gas Machinery Research Council 3030 LBJ Freeway, Suite 1300 Dallas, Texas 75234

Transcription

1 SYSTEMS MOUNTING GUIDELINES FOR SEPARABLE RECIPROCATING COMPRESSORS IN PIPELINE SERVICE Prepared by Anthony J. Smalley P. Joe Pantermuehl SwRI Project No Prepared for Gas Machinery Research Council 3030 LBJ Freeway, Suite 1300 Dallas, Texas December 2006 S O U T H W E S T R E S E A R C H I N S T I T U T E

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3 SOUTHWEST RESEARCH INSTITUTE 6220 Culebra Road San Antonio, Texas SYSTEMS MOUNTING GUIDELINES FOR SEPARABLE RECIPROCATING COMPRESSORS IN PIPELINE SERVICE Prepared by Anthony J. Smalley P. Joe Pantermuehl SwRI Project No Prepared for Gas Machinery Research Council 3030 LBJ Freeway, Suite 1300 Dallas, Texas December 2006 Approved: Danny M. Deffenbaugh, Director Mechanical and Fluids Engineering S O U T H W E S T R E S E A R C H I N S T I T U T E

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5 EXECUTIVE SUMMARY The objective of this GMRC project is to develop a consensus best-practice guideline for the installation of pipeline reciprocating compression equipment. The intent is to ensure installations that are free from damaging vibrations, operate reliably with acceptable alignment over the long term, and present the owner with affordable life cycle costs. The need for these guidelines was driven by a number of problem installations. The GMRC recognized that it was desirable for all segments of the industry to learn from such problems and so to minimize or avoid them in the future. This document presents a set of guidelines on the mounting of large horsepower, medium to high-speed, separable, reciprocating compressors for pipeline service. The emphasis is on modern separable compressors with low-pressure ratio, powers of 1,500 to 10,000 HP, and speeds of 500 to 1,200 RPM. Mounting includes support of the compressor, the driver, compressor cylinders, filter bottles, vessels, and other appurtenances. In addition, mounting covers the functions provided by the skid or skids, reinforcements, grout and concrete, the mat and foundation, anchor bolts and washers, mounting plates, chocks, piers, clamps, cylinder supports, frames, and other support structures. The guidelines are intended to capture the knowledge base, which has been accumulated across a number of organizations in the process of procuring, engineering, installing, and operating this class of compression over the last decade. The guide acknowledges that, in a competitive environment, without very explicit specifications in critical areas, packagers and other suppliers may make some decisions during the bid process on the basis of initial installed cost rather than integrity and long-life. Therefore, this guideline strives to provide the end-user with a framework and mechanism for requesting the same scope of work from all bidding organizations, which also helps the suppliers provide a competitive price on an equal basis. The document further emphasizes the due diligence needed by all stakeholders to ensure the installation meets expectations. This document is organized to provide the user both background and specific guidelines. The specific guideline is presented in Chapter 4, while the background information addressing why the guidelines are given is presented in the first three chapters. It is recommended that the first time user familiarize himself/herself with the overall subject by reviewing all four chapters. During implementation for a specific project, it is only necessary to refer to Chapter 4. SwRI Project Page ii

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7 TABLE OF CONTENTS Section Page EXECUTIVE SUMMARY... ii LIST OF FIGURES... x LIST OF TABLES...xvi 1. INTRODUCTION AND GENERAL BACKGROUND Introduction Scope of Guidelines Definitions and Terminology Mounting High and Medium Speed Package The Packager Integral Engine Compressor High Speed Driver with Low Speed Separable Compressor Grout Anchor Bolts Canister Bolt Chock Mounting Plate Sole Plate Cylinder Crosshead Crosshead Guide Crosshead Guide Support Wedge Grout Box Pedestal Coupling Alignment Double Spherical Washer Grout Expansion Joint Two-Piece Anchor Bolt Grout Head Box Foot Precision Shims Head End Support Vibracon Historical Perspective Slow Speed Compressors The Current Choice of Medium and High Speed Compressors Performance Implications...8 SwRI Project Page iv

8 TABLE OF CONTENTS (Cont'd) Section Page Growth of the Skid Mounted Packaged Compressor Standards for Packaged Compression Equipment Historical Mounting Practice in the Pipeline Industry Past Compressor Mounting Research Force Management Issues and Characteristics in Slow Speed Integrals Changes in Practice for Mounting Integral Engine/Compressors Attributable to Research and Experience Current Mounting Technology for Slow Speed Integrals Mounting Problems in Separable Compressors The Option to Block Mount Separable Compressors Situation Summary Typical Pipeline Compressor Applications Mainline Storage Mixed Service Lateral Line Compression Characteristics of Different Services Relevant Codes, Standards, Specifications, and Guidelines API 11P Specification for Packaged Reciprocating Compressors for Oil and Gas Production Services [6] API 618 Reciprocating Compressors for Petroleum, Chemical, and Gas Industry Service, 4 th Edition, June 1995 [8] API 686 Recommended Practices for Machinery Installation and Installation Design, 1 st Edition, April 1996 [7] ACI 351.3R-04 Foundations for Dynamic Equipment [9] ASTM A193 Standard Specifications for Alloy Steel and Stainless Steel Bolting Materials for High Temperature Service [10] ASTM A194 Standard Specifications for Carbon and Alloy Steel Nuts for Bolts for High Pressure and High Temperature Service [11] Compressor OEM Specifications to Packagers Driver OEM Guidelines Documents Available from GMRC SPECIFIC BACKGROUND The Compression System Physical Interfaces Forces to Recognize and Manage in Designing the Mounting System Skid Weight Weight of Compressor and Driver Weight of Cylinders and Crosshead Guides Primary Discharge Bottle Weight Primary Suction Bottle Weight...32 SwRI Project Page v

9 TABLE OF CONTENTS (Cont'd) Section Page Vertical Vessel Weight and Inertia Forces Other Horizontal Vessel Weight and Inertia Forces Rotating Unbalanced Forces Reciprocating Unbalanced Forces from Compressor Unbalanced Forces from Driver Compressor Cylinder Gas Forces Cylinder Gas Forces on Crosshead Guide Supports Potential for Imperfect Internal Balancing of Gas Forces Differential Stretch Forces Dynamic Gas Forces in Suction and Discharge Bottles Differential Vertical Forces for Compressor Installation Weight Forces Installation Fit-up Forces Piping Thermal Forces Compressor Frame Thermal Growth Forces Engine Block Thermal Growth Forces Grout to Concrete Thermal Growth Forces Compressor and Driver Anchor Bolt Forces Geometries to be Managed Compressor Frame Geometries Engine Geometries Motor Geometries Experience Base: Successes and Problems with Medium and High-Speed Separable Reciprocating Compressor Systems Survey Results and Tabular Experience Base Case Studies Technical Background and Topics to Support Specific Guidelines Geotechnical Assessment Pulsation: Methods of Analysis and Control Torsional Vibrations: Method of Analysis, Assessment, and Control Piping and Compressor Manifold Vibrations Modeling Methods and Examples Alignment: Discussion of Key Elements for Medium and High-Speed Separable Compressors and Their Drivers Anchor Bolt Tension Management and Monitoring Skid Structural Analysis: Treatment of Excitations Complicating Factors and Incompletely Resolved Issues GENERAL AND ORGANIZATIONAL GUIDELINES Organizations and Their Interfaces Responsibilities SwRI Project Page vi

10 TABLE OF CONTENTS (Cont'd) Section Page End User Responsibility Packager Responsibility for Skid-Mounted Units Compressor OEM Responsibilities Driver OEM Responsibilities Responsibilities for Foundation Design and Installation for Foundation and Skid Responsibilities of Third Party Analysts End User Due Diligence Needed Project Skills SPECIFIC GUIDELINES Bid Specifications Package Configuration Requirements General Requirements Design Analysis Requirements Skid Design Requirements Piping Design Requirements Foundation Design Requirements Installation and Mounting Design Requirements Alignment Requirements Installation Requirements Start-Up and Operation Requirements Choosing Skid or Block Mounting for Medium and High-Speed Separables Some Skid Mount Advantages Some Skid Mount Disadvantages Some Block Mount Advantages Some Block Mount Disadvantages The Current Experience Base for Block Mounting Skid Design Basic Requirements Specific Skid Design Guidelines Foundation Design for a Skid Mounted Compressor Basic Foundation Requirements Specific Guidelines for Skid Mount Foundation Design Foundation Design for a Block-Mounted Compressor and Engine Basic Requirements Specific Guidelines for Block-Mounted Compressor and Engine Piping Design and Design for Pulsation Control Basic Requirements Specific Guidelines Design and Specification of Mounting and Installation SwRI Project Page vii

11 TABLE OF CONTENTS (Cont'd) Section Page Overview and Basic Requirements Skid to Foundation Mounting Compressor Mounting (To Skid or Block) Driver Mounting (To Skid or Block) Crosshead Guide Mounting (To Skid or Block) Cylinder Head End Support Mounting to Foundation (If Required) Discharge Bottle to Foundation Block Mounting Suction Bottle Structural Support Mounting: Use a Grouted, Anchor Bolted Support Vessel Mounting Analytical Studies Overview Pulsation Analysis Torsional Analysis Piping and Compressor Manifold Vibration Study Structural Analysis of Skid and Mounted components Foundation Analysis Piping Stress and Flexibility Analysis Installation Basic requirements General Installation Guidelines Foundation Installation Preparations for Grouting of Skid to the Concrete Grouting Alignment of Equipment Installation of Pulsation Bottles and Piping Ensure Piping and All Bottle Chambers are Thoroughly Clean Before Installation and Operation Start-Up and Commissioning General Prior to Coupled Operation, Perform Uncoupled Runs and Tests of Driver Apply Compressor and Driver Checklists Perform Start-Up with Compressor on an Adequately Sized Bypass Perform Appropriate Hot Alignment Checks on Main Equipment Check and Re-Tighten All Frame Anchor Bolts on Driver and Compressor Once Hot Operating Conditions have Stabilized Continue the Short-Term Check and Retighten Cycle for Anchor Bolts Until Clear Evidence of Day-to-Day Repeatability is Obtained Check and Adjust Crosshead Guide Support Shims Under Hot Conditions SwRI Project Page viii

12 TABLE OF CONTENTS (Cont'd) Section Page Adjust Wedges Under Discharge Bottles with the Operating Temperature Stable Adjust Head End Supports Under Hot Conditions, If the Design Includes Them Adjust Suction Bottle Clamps and Wedges Once Stable Operating Conditions Have Been Reached Rigorously Confirm That All Wedges on Both Sides of the Unit Have Been Properly Adjusted, Including Those Below Floor Level Start-Up Testing General Scope of Start-Up Vibration Testing Perform Start-Up Vibration Tests According to Test Matrix, and Apply Appropriate Vibration and Pulsation Criteria Evaluate Any Non-Compliance Between Test Data and Criteria Decide on Further Documentation and Problem Definition Perform Engine Testing for Heat Rate and Compressor Testing for Efficiency and Capacity, In Addition to Performing and Evaluating Vibration Tests Corrective Action for High Vibration Evaluate Options for Corrective Action Implement Corrective Action Longer Term Operation ACKNOWLEDGEMENTS REFERENCES COMPRESSOR MOUNTING AND FOUNDATION BIBLIOGRAPHY APPENDIX A Experience Base Presented as 13 Tables... A-1 SwRI Project Page ix

13 LIST OF FIGURES Figure Page Figure 2-1 Large Skid for 5,000 HP Motor Driven JGU/Z, with Beams Alone Weighing Over 85,000 lbs and Completed Skid Weighing Over 220,000 lbs After Addition of Concrete...30 Figure 2-2 Crane Lift of Skid with 6-Cylinder Ariel JGD Compressor Already Mounted Figure 2-3 Rugged Support Structure for 4-Chamber (3 + Common Chamber) Suction Filter Bottle on JGU6, Replacing 3-Chamber...33 Figure 2-4 Cat G3616/Ariel JGD6 Installation (5 Units)...34 Figure 2-5 Ariel JGD4 Installation Showing Modifications to Control Observed Vibrations: Cylinder Supports Grouted with Anchor Bolts at Their Base; An Increased Number of More Rugged Clamps; An Increased Number of More Rugged Wedges; Cross-Bracing on Suction Chokes; Added Cross Beams to Skid Structure...34 Figure 2-6 Model of Block and Frame of Separable Slow Speed Compressor Used for Calculating Anchor Bolt Transverse Loads...36 Figure 2-7 Comparison of Maximum Transverse Force as Predicted by Rigid Frame ( RIGID ) Assumption, by Finite Element Analysis ( FLEX ), and by Frame with Zero Bending Stiffness ( SOFT )...37 Figure 2-8 Cross-Bracing Between Suction Bottles...41 Figure 2-9 Schematic of a Cylinder, Showing Also Piston, Piston Rod, Crosshead, Crosshead Bearing, Pin Bearing, Connecting Rod, and Crankshaft Figure 2-10 Illustration of Load Balance at Crosshead Pin from Which Vertical Force on Crosshead Bearing is Determined...42 Figure 2-11 Axial View of Ariel JGC:D Frame...44 Figure 2-12 Axial View of Ariel JGU:Z Frame...45 Figure 2-13 Axial View of Ariel KBB:V Frame...46 Figure 2-14 Cross-Section of Wartsila Engine...47 Figure 2-15 Cat GCM Cross-Section...48 Figure 2-16 Cat G3600 Series Engine Oblique Cutaway...48 Figure 2-17 End Elevation of Cat G Figure 2-18 Pedestal for Skid Mounted Wartsila Engine...50 Figure 2-19 Engine Skid for G Figure 2-20 Concrete Well to Accommodate GCM34 Sump for Concrete Block Mounted Installation of 8180 HP Engine and Ariel JGV6 compressor...51 Figure 2-21 Typical Induction Motor Dimensions 680-Frame (Courtesy Siemens) Figure 2-22 Typical Induction Motor Dimensions 800-Frame (Courtesy Siemens) Figure 2-23 Typical Induction Motor Dimensions 1120 Frame (Courtesy Siemens) Figure 2-24 Overview of Cat G3608 Driven Ariel JGD Figure 2-25 Vertical Vibrations on Cylinders 2 and 4 of the Compressor of Figure SwRI Project Page x

14 LIST OF FIGURES (Cont'd) Figure Page Figure 2-26 Vertical Vibrations on Cylinders 1 and 3 of the Compressor of Figure Figure 2-27 Comparison of 4 th Order Vibrations for Cylinders 1, 2, 3, and 4 with Ineffective Head End Supports at Cylinders 1, 2, and Figure 2-28 ANSYS Model of Ariel JGD4 with Cylinders, Bottles Head End Supports, Viewed with Orientation Similar to Figure Figure 2-29 Mode Shape for 48.7 Hz Cylinder-Bottle Mode without Head End Support Figure 2-30 Mode Shape for 50.1 Hz Cylinder-Bottle Mode without Head End Support Figure 2-31 Mode Shape for 53.1 Hz Cylinder-Bottle Mode without Head End Support Figure 2-32 Mode Shape for 53.7 Hz Cylinder-Bottle Mode without Head End Support Figure 2-33 Figure 2-34 Figure 2-35 Figure 2-36 Figure 2-37 Influence of Crosshead Guide Support Stiffness on Frequency of the Four Predicted Cylinder-Bottle Modes...64 Influence of Discharge Bottle Wedge Support Stiffness on the Frequency of the Four Predicted Cylinder-Bottle Modes...65 Illustration of Bottle Ovalization in Response to Nozzle Vertical Load and Rigid Wedge Under Bottle...65 Influence of Cylinder Head End Support Attachment Stiffness on the Four Predicted Cylinder-Bottle Modes...66 Need for Head End Support Influence on Vertical Cylinder-Bottle Modes and Comparison with 4 th Order Excitation Range...67 Figure 2-38 Comparison of Cylinder Maximum Vibration Component Before and After Modifications, which Include Re-Grout of Head End Supports and Added Anchor Bolts...67 Figure 2-39 Cat G3608 Engine Mount Before Modification to Control Vibrations and Soft Foot Under Vibracons...70 Figure 2-40 Close-up: Cat G3608 With Vibracon Mounts With Steel Plates Between Vibracons and Skid...71 Figure 2-41 Motor-Driven Ariel JGV Figure 2-42 Crosshead Guide Support and Compressor Pedestal for Motor Driven Ariel JGV Figure 2-43 Peak Hold Spectrum Load Step 5 (Asymmetric)...74 Figure 2-44 Peak Hold Spectrum Symmetrical Load Step (Load Step 1) Figure 2-45 Vertical Vibration Profile Motor-Driven Unit 156 Hz Figure 2-46 Model of Cylinder, Frame, Bottles, and I-Beam Support Structure...75 Figure 2-47 Model Without Bottles...76 Figure 2-48 I-Beam Pedestal Structure (Plate Model)...76 Figure 2-49 Detail Showing Compressor to I-Beam Interface...77 Figure 2-50 Case Study 2 Predicted Mode Shape at 98.9 Hz...77 SwRI Project Page xi

15 LIST OF FIGURES (Cont'd) Figure Page Figure 2-51 Figure 2-52 Figure 2-53 Axial Profile of Frame Vibration Amplitudes Under Asymmetric Unbalanced Gas Loading...78 Compressor Base Response (Horizontal, Perpendicular to Cranshaft) as a Function of Frequency...79 Vertical Profile of Vibration Amplitudes (Horizontal, Perpendicular to Crankshaft)...79 Figure 2-54 Compressor Base Response as a Function of Frequency Under Asymmetric Loading; Pedestal Stiffness Increased by 4X; No Sliding at Mount...80 Figure 2-55 Vertical View Profile of Frame Vibration Amplitudes, Corresponding to Peak of Figure Figure 2-56 Minimum Friction Coefficient for Cast-Iron on Various Other Materials, from GMRC Technical Report TR97-3 [2]...81 Figure 2-57 Siemens Motor Driven JGV6 with Replacement 4-Chamber Suction Bottle Installed and Rugged Support Structure for Suction Bottle...82 Figure 2-58 Rugged Support Structure for New 4-Chamber Bottles in More Detail Showing Clamp Holding Bottle Against Wedges and Long U-Bolts Providing Substantial Bolt Stretch Length...82 Figure 2-59 Comparison of Primary and Secondary Discharge Bottle Configuration Against Single 4-Chamber Discharge Bottle...83 Figure 2-60 Original Discharge Bottle on JGU6, With No Clamps Holding Bottle Against Wedges...85 Figure 2-61 Original 3-Chamber Suction Bottle on Ariel JGU6 Driven by Cat G Figure 2-62 Illustrative Prediction of JGU6 Compressor Manifold Vibration Figure 2-63 Discharge Bottle with Added Strap to Control Vibrations; Ariel JGU6 Installation...87 Figure 2-64 JGU6 with Replacement 4-Chamber Suction Bottle...87 Figure 2-65 Original Installation of G3520-JGT Figure 2-66 Views of Modified Installation of G3520-JGT Figure 2-67 Very Stiff Crosshead Guide Support, which is a Single Structure for Two Adjacent Cylinders; Installed to Control Cylinder Vibrations Identified with Less Stiff Individual Cylinder Guide Supports...89 Figure 2-68 Three-Dimensional Schematic of Common Chamber Suction Filter Bottle [14]...92 Figure 2-69 Model of Manifold System, Piping, and Cylinders for 6-Cylinder Single- Stage Compressor, which Uses Shell Elements for 4-Chamber Suction and Discharge Bottles...95 Figure 2-70 Details of Model at Joint Between Nozzle and Suction Bottle Showing Shell Elements Used for Bottle and for Reinforcing Pad Figure 2-71 Predicted Stress Distribution in Bottle Modeled with Beam Elements SwRI Project Page xii

16 LIST OF FIGURES (Cont'd) Figure Page Figure 2-72 Predicted Stress Distribution in Bottle Modeled with Shell Elements Figure 2-73 Figure 2-74 Beam Element Model of Compressor Manifold...97 Shell Element Model of the System Modeled with Beam Elements in Figure Figure 2-75 Velocity Spectrum Predicted with Beam Elements (Model of Figure 2-73) Figure 2-76 Velocity Spectrum Predicted with Shell Elements (Model of Figure 2-74) Figure 2-77 Stress Distribution Predicted with Beam Element Model of Figure Figure 2-78 Stress Distribution Predicted with Shell Element Model of Figure Figure 2-79 Predicted Vibration Velocity for Unbraced Suction Bottles Figure 2-80 Predicted Vibration Velocity for Braced Suction Bottles Figure 2-81 Figure 2-82 Figure 2-83 Cat G3608 Installation; Vibracon Mounts with Jacking Screws for Vertical and Horizontal Motion Simplified Illustration of Forces and Couples Acting on a Compressor Frame Free Body Diagrams for Two Contacting Bodies Illustrating Friction Forces in Reaction to Externally Applied Forces Figure 2-84 Schematic of Canister Bolt (Courtesy Robert L. Rowan) Figure 2-85 Illustration of Anchor Bolt and Compressed Sandwich, Including Grout Layer Figure 4-1 Foot of JGV6 Compressor Driven by Wartsila 18 Cylinder Engine Figure 4-2 Figure 4-3 Figure 4-4 Figure 4-5 Compressor Foot of JGD4 Driven by Cat G3616, Mounted on Chock Set in Grout Box Stiff Crosshead Guide Support Connecting JGV6 (GCM34 Drive) Guide Directly to Block Skid Being Lifted Into Position on Foundation Block Prior to Grouting to Block Stiff Crosshead Guide Structure Covering 2 Cylinders of Ariel JGD4, Driven by Cat G Figure 4-6 Crosshead Guide Support for Wartsila Engine Driven JGV Figure 4-7 Compressor Section of Skid Before Compressor is Mounted Figure 4-8 Close-Up of Jacking Screw for Skid of Figure Figure 4-9 Anchor Bolt for JGV6 Compressor Frame Extending Below Skid Figure 4-10 Box Structure for Achieving Stretch Length for Anchor Bolts Figure 4-11 Bottle Mounted on Skid and Resulting Elevated Compressor Mounting Figure 4-12 Figure 4-13 Foundation Block for Cat G3612 Installation Staggered Concrete Levels as a Means of Controlling Height from Which Discharge Bottle is Supported SwRI Project Page xiii

17 LIST OF FIGURES (Cont'd) Figure Page Figure 4-14 Underside of Skid for Cat G3616/JGD6 Installation, Showing Concrete in Skid Under Compressor, and Jacking Screws for Leveling and Alignment Along the Side Figure 4-15 Crosshead Guide Supports and Anchor Bolts for JGV Figure 4-16 Mounting Foot Mounted on Chock Set in Grout Box, With Shims Between Chock and Foot for Alignment and Leveling Figure 4-17 Cat G3616 Engine Mounting Foot, with Adjustable Vibracon Supports Mounted Directly onto Skid Figure 4-18 Freestanding Stretch Tube on Compressor Pedestal for JGV6 Installation Later Reinforced with Horizontal Plate Mid-Way Down Bay Between Gussets Figure 4-19 Mounting for 4-Chamber Suction Bottle Support Structure Retroactively Installed on JGV Figure 4-20 Mounting of Structural Support for 4-Chamber Bottle Retroactively Designed and Installed for JGU Figure 4-21 Block Mounted JGV6 Installation Figure 4-22 Schematic of Canister Bolt (Courtesy Robert L. Rowan) Figure 4-23 Photograph of Several Canister Bolts (Courtesy Robert L. Rowan) Figure 4-24 Siemens Motor Driven JGV6 with Replacement 4-Chamber Suction Bottle Installed and Rugged Support Structure for Suction Bottle Figure 4-25 Acoustic Filter Options Which Impact Mounting Figure 4-26 Cat G3612 Driven Installation Figure 4-27 JGT4 Installation; Rugged Low Profile On-Skid Mounting of Secondary Bottle Figure 4-28 Cat G3616/JGD6 Installation (5 Units) Figure 4-29 Robust Off-Skid Mounting for Lateral Piping Figure 4-30 Cat G3608 Installation Showing Bracket Added to Control Piping Vibration Figure 4-31 Cat G3608 Installation With Added Clamping on Piping Figure 4-32 Pipe Support Added to Insulated Elbow Figure 4-33 Insulated Flange at Building Wall Installed Before Wall was Installed and Now Very Difficult to Get a Wrench to Because of the Wall Figure 4-34 Skid for Ariel JGT4/Cat G3520 Installation With Grout Showing Anchor Bolt With Supernut and Jacking Screw for Leveling Skid Figure 4-35 Corner of Skid Showing Grouting, Skid Anchor Bolt, and Skid Jacking Screw Figure 4-36 Epoxy Filled Self-Aligning Mount (U.S. Rotech, Inc.) Figure 4-37 Riverhawk Stud Tensioner Graphic (from SwRI Project Page xiv

18 LIST OF FIGURES (Cont'd) Figure Page Figure 4-38 Figure 4-39 Schematic of Alternative Adjustable Mount Patent Pending (Courtesy Robert L. Rowan and Associates) Photograph of Alternative Adjustable Mount Patent Pending (Courtesy Robert L. Rowan and Associates) Figure 4-40 Packager Shop Installation of Cat G Figure 4-41 JGD4 Installation Showing Tuning Mass Added to Head End Support to Change Natural Frequency from Value Leading to Very High Torsional Vibration of Support Figure 4-42 JGD4 Installation Figure 4-43 Close-up: More Rugged Clamp and Wedge on JGD4 Installation Figure 4-44 Cat G3616/JGD6 Installation (5 units) Figure 4-45 JGD3 Installation Driven by Cat G Figure 4-46 Piers Constructed to Support Retrofit Bottles Figure 4-47 Vibration Induced Stresses and Allowable Vibrations For Piping Spans Figure 4-48 Finite Element Model of Concrete Block for Calculating Concrete Stresses Figure 4-49 Field Sandblasting Bottom of Skid [12] Figure 4-50 Expansion Joint Foam in Position [12] Figure 4-51 Movable Head Box [12] Figure 4-52 Head Box on one Side of Skid Being Filled with Grout Figure 4-53 Grout Pulling Tool [12] Figure 4-54 Grout Pulling Tool in Use [12] SwRI Project Page xv

19 LIST OF TABLES Table Page Table 2-1 Table 2-2 Table 2-3 Table 2-4 Typical Compressor Heights From Under-Surface of Feet to Crankshaft Centerline...47 Caterpillar Engine Mode Heights from Low Point and from Under-Surface of Feet to Crankshaft Centerline...51 Representative Motor Dimensions: Heights of Siemens Motors from Under- Surface of Feet to Shaft Centerline...55 Comparison of Predicted Response Frequencies for Manifold and Piping Based on Beam and Shell Models...98 Table 2-5 Anchor Bolt Forces (lbs) for Different Sizes and Stress Levels Table 2-6 Full Load Rolling Torques for Cat G3608 and G Table 2-7 Full Load Rolling Torques for Cat G3606 and G Table 2-8 Cat Large Engine Dynamic Significant Linear and Torsional Excitation Frequencies SwRI Project Page xvi

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21 1. INTRODUCTION AND GENERAL BACKGROUND This document has four main sections: 1 Introduction and General Background 2 Specific Background 3 General and Organizational Guidelines 4 Specific Guidelines This first section introduces the subject, the scope of the guidelines, some relevant definitions and terminology, and the recent evolution in upstream and pipeline compression. A situation summary defines current experience leading to the need for guidelines, followed by a summary of existing codes, standards, specifications, guidelines, and how they should be supplemented when applied to pipeline separable compressors. The second section provides a more specific definition of the factors influencing the procurement, engineering, and installation of medium and high-speed compressors in pipeline service, and the challenges faced by the end user s project engineering team. It includes subsections on the forces to be managed, the driver and compressor geometries to be managed, and experience from the end users and other industry segments with a number of case studies. The second section concludes with technical discussion, which provides background for the specific guidelines in Section 4 of this document. The relevant sub-section (2.6) identifies state-of-theart limitations, pointing to areas where research is needed to comprehensively support the reliable engineering of separable reciprocating compressors in the future. The third section provides qualitative, but significant guidance for planning and organization of a project to install one or more medium or high speed separable reciprocating compressors in pipeline service. It includes a definition of responsibilities, the due diligence required of the end user s project engineer, and needed project skills. The last and longest of these four sections provides specific guidelines on specification, design, design analysis, mounting, installation, start-up, testing, and corrective action. Additional sections include references, a bibliography, and an appendix containing a tabular experience base obtained by industry survey. 1.1 INTRODUCTION This document presents a set of guidelines on the mounting of separable reciprocating compressors, with speeds generally referred to as medium and high speed. The guidelines are intended to capture the knowledge base, which has been accumulated across a number of organizations in the process of installing such compressors between 1997 and The need for these guidelines arises because certain problems arose, often for identifiable reasons, and it is desirable for all segments of the industry involved to minimize or avoid such problems in the future. Such problems have frequently resulted in unanticipated and undesirable extra cost often to a number of the stakeholders. Delays in the added capacity anticipated from new compression has been another common result. The first half of the guidelines document provides background, and the second half presents general and specific guidelines. SwRI Project Page 1

22 The guidelines, appropriately followed, should help project stakeholders install separable compressors that encounter a minimum of problems, that enhance reliable deliverability of the U.S. pipeline system, that represent valuable business assets to pipeline companies, and that the diverse supplier teams can profit from with justifiable pride. In a number of areas, the work of assembling and preparing the guidelines has revealed gaps or limitations in the current state-of-the-art. These areas will need research to advance knowledge and practice to the point where it can comprehensively support effective engineering for mounting and installation of medium and high speed separable compressors in pipeline service. 1.2 SCOPE OF GUIDELINES These guidelines will address the mounting of separable reciprocating compressors for pipeline service. Mounting includes support of the compressor, the driver, compressor cylinders, filter bottles, vessels, and other appurtenances; it covers the functions provided by the skid or skids, reinforcements, grout and concrete, the mat and foundation, anchor bolts and washers, mounting plates, chocks, piers, clamps, cylinder supports, frames, and other support structures. The guidelines will emphasize modern, high-speed separable compressors, with power of approximately 1,500 HP and above, with either fixed or variable speeds in the range from 500 to 1,200 RPM. The guidelines will seek to address decisions, which will influence the short and long term integrity and economics of the installation whose expected life for pipeline service can be expected to exceed at least 20 years. These decisions include both hardware choices and the design analyses, which guide and validate these hardware choices. The guidelines also emphasize less tangible but vital issues communication, due diligence, and the management of interfaces both physical and organizational. As stated, the guidelines will emphasize pipeline service, but should also be relevant to other installations with long life requirements. Those responsible for installations in other services may choose to apply many of the general aspects of the guidelines but should recognize the special considerations of pipeline service implicit in the guidelines (typically single stage, ratio below 1.5, high availability requirements, with need for high thermal efficiency, and long service life). The guidelines will consider alternative mounting types, particularly block mounting and skid mounting. In general, the guidelines do not address slow speed integral compressors, although some of the lessons learned from experience over the lifetime of the large number of slow speed integrals in pipeline service will be adapted to the present guidelines. 1.3 DEFINITIONS AND TERMINOLOGY MOUNTING Mounting is the location, weight support, alignment, mechanical and gas load management, and tie-down of the compressor, its driver, associated systems, and appurtenances. SwRI Project Page 2

23 1.3.2 HIGH AND MEDIUM SPEED For the purposes of these guidelines, high speed is considered to be 900 RPM and above. Medium speed is 500 to 900 RPM. These definitions are somewhat arbitrary and do not greatly influence the mounting guidelines PACKAGE In principle, a package is the compression system everything between the suction flange and the discharge flange, with a driver and support systems; a turnkey system which just has to be set in place, connected to compressor station gas headers, connected to fuel or power lines, started, and operated. In fact, it is this turnkey concept, which needs some qualification and rethinking when applied to large pipeline compressors, as the guidelines will discuss THE PACKAGER The Packager is the single source and point of contact for the procurement, engineering, assembly, transportation, installation, start-up, commissioning, and problem resolution for the compression system. The packager purchases and assembles the compressor, driver, coupling, vessels, coolers, controls, oil system, etc., designs a skid, mounts the components on the skid, delivers the package to the end user, installs it, starts it up, and assures its function as a system for a finite period. When not explicitly specified by the purchaser, the packager normally decides and procures the engineering analyses, which will be employed to support the design. Considering all industry segments they serve, packagers offer sale, lease, or contract operation INTEGRAL ENGINE COMPRESSOR A compressor and engine in the same frame, normally burning the same gas that it compresses, whose single crankshaft transmits power from the power cylinders to the compressor cylinders. Often referred to as slow speed integral engine compressors, their speed is most commonly from 200 to 475 RPM. These guidelines are not directed at such units, but where possible seek to take advantage of the existing knowledge base for integral engine compressors HIGH SPEED DRIVER WITH LOW SPEED SEPARABLE COMPRESSOR This configuration has been proposed on occasion for pipeline service with the potential advantages of combining the high thermal efficiency of a low speed compressor with the low heat rate of a modern high-speed engine. It includes a gearbox to reduce speed from the engine to the compressor. A small number of examples exist in other services. Many of the principles developed in these guidelines would apply to this configuration, but it is not explicitly addressed in these guidelines GROUT A pourable material, which cures and hardens with time, to form a stiff layer, and fills the previously empty space into which it has been poured. The hardened grout forms a structural element of the mounting system for skids, sole plates, chocks, compressors and their drivers. Once the grout is hardened, anchor bolts are tightened at certain locations on mounted equipment or a skid, with the effect of compressing the grout. Grouts in this application are epoxy material formed from long chain polymer compounds, which can be formulated to provide a Young s SwRI Project Page 3

24 modulus of 1.5 million PSI or more. The modulus has a time dependent characteristic sometimes referred to as creep, which can cause slow changes in deflection under load. Grout properties are also temperature dependent, which must be accounted for during start-up and initial operation ANCHOR BOLTS Anchor bolts for compression equipment normally pass upwards through a hole in a plate, flange, or foot, and via a nut and washer, apply a vertical downwards force on the upwards facing surface of a component to be mounted (of which the plate, flange, or foot forms an integral part). Anchor bolts may be embedded in concrete or may be terminated at their lower end by a head, which bears against a surface of the steel structure onto which the component is to be mounted CANISTER BOLT An anchor bolt designed for installation in concrete with a termination disk at its lower end for embedment in the concrete and an encasing sleeve covering the entire length of the bolt, which helps protect the bolt. The bolt can usually be temporarily lowered into the canister flush with or below the concrete surface, if needed, then raised up again to interface with mounted equipment CHOCK A chock is a stiff, flattish element, rectangular in plan view, with typical dimensions of 6 to 12 inches on a side, and 1 to 3 inches of thickness. A chock separates a component to be mounted from the structure to which it is to be mounted. Normally, a single anchor bolt passes through the chock, and the tensioning of the anchor bolt produces a high normal force between the interfaces involved (e.g., the compressor to chock interface, the chock to skid interface, or the chock to concrete interface) MOUNTING PLATE This component is similar to a chock on which the compressor and driver feet are amounted and which, in turn, is solidly supported by the skid. Often, the mounting plate is set in a rectangular box containing grout, and the box is welded to the skid or to a pedestal structure for mounting the engine or compressor SOLE PLATE A sole plate performs some similar functions to a chock or mounting plate but normally has a larger area in plan view. The sole plate is normally grouted in place on top of a concrete block providing multiple points of support for a compressor or driver CYLINDER This is a compressor component, which contains the compressed gas as it changes pressure under the action of the piston and its motion. The cylinder incorporates suction and discharge valves, gas flow passages, and packing. The valves manage the gas flow into and out of the cylinder volumes and trap the gas while it is being compressed under the action of the reciprocating piston. There is most commonly one cylinder per throw, and an equal number of SwRI Project Page 4

25 cylinders on each side of the compressor, although variations on this configuration have been successfully installed CROSSHEAD A sliding component, which moves along a straight line, guided by a slider bearing and acted upon by the connecting rod. The crosshead is the slider of this slider-crank mechanism. The piston rod projects from and is driven by the crosshead; the piston rod imposes reciprocating motion on the piston CROSSHEAD GUIDE A structural element to which the cylinder is attached at its outer end and which at its inner end is connected to the compressor frame. It acts as a spacer between frame and cylinder. It also partially supports the crosshead guide slider bearing, which keeps the crosshead moving in a straight line. Some compressors also have a separate compartment, called a distance piece, between a crosshead guide and a cylinder CROSSHEAD GUIDE SUPPORT The crosshead guide support is a structural element, which provides vertical support, vertical restraint, and axial restraint to a cylinder and crosshead. It typically attaches to a crosshead guide or cylinder near the joint between crosshead guide and cylinder WEDGE This is an incline plane device to hold and restrain a bottle or section of pipe. Used strictly in pairs these present flat surfaces at about 45 degrees to the vertical below and on either side of the bottle. Wedges are adjustable by means of long bolts, which pull the pair of wedges together to tighten them against the bottle. With high or variable discharge temperatures, the vertical growth of discharge nozzles requires care in the use of discharge bottle wedges, but for pipeline applications, this is the preferred configuration for bottle support GROUT BOX A metal box, open from above, normally with rectangular or square cross-section as seen from above, welded to the top of a main skid beam member, with sides several inches high. The box is filled with epoxy grout and a plate (normally milled steel) is set in the grout, with its upper surface horizontal, and typically with about 2 inches of grout under the plate. The box and plate act as a mount for the feet of a compressor and driver, so the plate and box have holes for one or two anchor bolts located to match bolt holes in the feet of the machine to be mounted at that location PEDESTAL A structure, commonly built of I-beams or wide flange beams, to provide a mounting surface at appropriate height for the compressor or its driver on the skid. An important function of the pedestal under the engine is to locate the engine s feet so the sump s lowest point is at the desired position relative to the main skid. The function of a pedestal under the compressor (if a pedestal is used here) is to elevate the compressor shaft centerline to the same level as that of the driver. SwRI Project Page 5

26 COUPLING The device used to connect shafts of driver and compressor. Couplings used for medium and high speed compressors most commonly offer some tolerance to angular and transverse offset between driver and compressor, achieved with a spool piece between angularly flexible joints mounted on each shaft (though low speed separables sometimes use a rigid, flanged, coupling). Compressor OEMs normally recommend a coupling, which is torsionally stiff but allow for a torsionally soft coupling, if shown by torsional analysis to be needed. Couplings of all types are a maintenance item. Examples of various different coupling models are seen in practice ALIGNMENT Alignment normally refers to the process of adjusting the position of driver and compressor on their mounts so the shafts of each are very close to collinear while avoiding undesired axial or thrust forces at normal operating temperatures. Alignment is further used in this document to refer to the leveling and elimination of twist and bending within the frame of both driver and compressor DOUBLE SPHERICAL WASHER A pair of washers mounted adjacent to a nut on an anchor bolt, with a spherical interface between them. This pair of washers provides a flat interface with the nut or bolt cap to avoid point loading. By allowing small relative angular motion between the pair of washers at the spherical interface, any lack of parallelism between the surfaces is accommodated, and pressure can be transferred with acceptable uniformity across these interfaces GROUT EXPANSION JOINT A soft element often of neoprene foam or polystyrene, typically 2 to 3 inches high and 0.5 to 1.5 inches wide, extending most commonly in a direction parallel to the crankshaft of driver or compressor, and across the width of a skid to be grouted in place, located immediately on top of a concrete foundation. The expansion joint acts to break up the layer of grout poured between the concrete and skid mounted on the concrete into rectangular sections. These joints are typically spaced three or four feet apart. Their benefits are to reduce the probability of thermal stress cracking and to break up the grout pour into manageable segments TWO-PIECE ANCHOR BOLT A bolt used in concrete foundations with two segments (pieces). The lower segment is embedded in the concrete and held against upwards pull by a termination device (nut, washer, or disk); the lower segment does not extend above the top of the concrete block section in which it is embedded, but allows for a second, upper, segment to be attached to the lower segment by a threaded sleeve. The upper segment extends above the concrete high enough to mount whatever is to be mounted. It is typical to provide a free work gap area in the concrete around the top of the lower segment so the joint can be made without difficulty GROUT HEAD BOX A box typically constructed of plywood, with rectangular (~9 X36 ) cross-section when viewed from above, with sides of 9 to 12 inches in height, and an opening at the bottom of one SwRI Project Page 6

27 long side, running the length of that side. The head box is set firmly against the side of a skid to be grouted in place, flat on the concrete surface, and filled with grout. The height of the grout in the box sets the head driving the flow across the volume between skid and concrete FOOT This is a localized component integral with or bolted to a compressor or engine frame for use in mounting. The foot presents a flat surface, facing downwards, which mates with a mounting plate facing upwards, with precision thickness shims or sometimes with an adjustable mount between the foot and the mounting plate PRECISION SHIMS Flat metal strips of uniform, and precisely known thicknesses, used to adjust height between a mounting plate and foot. Plastic shims should not be considered for pipeline applications. Specification of stainless steel shims will be subsequently recommended HEAD END SUPPORT This is a structural element, which restrains motion of the cylinder, attached near the outboard end of the cylinder, sometimes called an outboard cylinder vibration suppression device. For integral engine/compressors, a similar device was often referred to as a cold support. However, for high-speed separable compressors, it functions predominantly to control vibration VIBRACON A mount of cylindrical shape, used increasingly to support engine drives from the skid, which provides vertical adjustability and self-alignment and thereby can aid in vertical alignment of mounted equipment. 1.4 HISTORICAL PERSPECTIVE SLOW SPEED COMPRESSORS The natural gas transmission industry has made heavy use of reciprocating compressors at stations along the pipeline system. These compressors move the gas and overcome frictional resistance to flow between stations. When first applied in this industry, the compressors were slow speed first, the 88 to 180 RPM horizontal compressors, and then the 200 to 475 RPM engine-compressor combinations, now termed slow speed integrals (the Cooper Quad is an engine/compressor example at the high end of the 200 to 475 RPM speed range). These slow speed integrals still form the backbone of the pipeline system, and economics will drive most pipeline companies to keep these integrals operating for as long as possible (while responding to regulatory constraints). Over the years, centrifugal compressors have also become a popular choice, and a significant fraction of the system s expansion since 1960 has come through deployment of gas turbine driven centrifugal compressors. However, most operating companies must deal with widely varying conditions and have determined that a mix of reciprocating and centrifugal compressors provide the operating flexibility they need. Thus, they will continue to operate their old, slow speed, integral, engine compressors even with the added constraint of environmental SwRI Project Page 7

28 regulation, and will add (or replace) horsepower with a balanced mix of centrifugal and reciprocating compressors THE CURRENT CHOICE OF MEDIUM AND HIGH SPEED COMPRESSORS While on rare occasions a slow speed unit may be chosen, present trends show clearly that the majority of new or replacement reciprocating compression in pipeline service will be medium and high speed separable compressors, with a mix of gas engine and electric drivers. The sustained emphasis on reciprocating compressors results in part from economics as well as operating considerations a very competitive market exists for high and medium speed separable engine compressor packages; the engines now have very attractive heat rates (5,900 to 6,600 BTU/BHP-Hr); and under specific operating conditions, the positive displacement reciprocating compressor can achieve thermal efficiencies at 90% or more. The shorter stroke of a high-speed compressor reduces the required span of the cylinders and frame in the horizontal direction perpendicular to the crankshaft. This reduces the amount of steel and cast iron needed to achieve the kinematic requirements of reciprocating piston motion, and significantly reduces the cost of a medium or high-speed separable package PERFORMANCE IMPLICATIONS The shorter cylinders of medium and high-speed separables also reduce the natural area available for gas to flow in and out of the cylinder for a given capacity. This reduced flow area increases the flow resistance because the gas flows through the valves and cylinder passages with higher velocity, related pressure drop varies with the square of flow velocity. The result of this higher flow resistance is seen especially in pipeline compressors across which the pressure rise tends to be a fairly small fraction of the line pressure (compression ratios as low as 1.1 are quite common). Effort is expended by compressor manufacturers to maximize the flow area for a given cylinder size for pipeline application, but the physical configuration constrains how far this can go. The attached compressor manifold system, nozzle orifices, and in pipeline applications, filter bottles incur as much as 10% additional pressure drop GROWTH OF THE SKID MOUNTED PACKAGED COMPRESSOR The growth of the market for packaged separables has come from the needs of the gas industry upstream of the regulated pipelines. Compression needs exist at the wellhead, in gathering systems, in gas processing, and in boosting of gas pressure to meet pipeline inlet requirements. The needs to link gas supply sources to pipelines and thereby to gas markets are fast moving and opportunistic. Numerous packager companies formed to meet these upstream needs the packager would provide turnkey compression, take care of the many logistical issues involved in compression, and offer a flexible and competitive range of lease, rental, purchase, or contract operation options. Most compressor and engine manufacturers provide their products only through packagers. In the process, the packagers learned how to engineer, procure, assemble, transport, deliver, and install at site an integrated, operating package for the lowest possible cost a natural and innovative result of competition. The skid mount was a natural choice from the start it can be designed, cut from I-beam, and welded up and partially to completely filled with concrete in the packager s shop. There, it provides a base in a relatively clean environment to assemble and component test the gas scrubbing and gas piping systems, oil system, cooling system, electric SwRI Project Page 8