Asia Turbomachinery & Pump Symposia

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2 Case Studies on Unique Machinery Repair Techniques: Brush Plating Repair of Eroded Compressor Diaphragm - Combining 2 Failed Gearboxes into 1 Functional and Reliable Gearbox
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Uptigrove, Stan; Tze-Hur, Chin; Edward, Karl
Case Study 2: When machinery challenges arise in aging equipment within declining oil and gas facilities it requires innovative solutions taking into account life expectancy, production impact and declining production to establish fit for purpose solutions. With good engineering, unique repairs can help limit production impact, extend equipment life and provide a more robust solution for current operating conditions. Two case studies of novel equipment repairs are presented to demonstrate these principles: 1. Brush Plating Repair of Eroded Compressor Diaphragm; and, 2. Combining Two Failed Gearboxes into One Functional and Reliable Gearbox. Focus was on restoring safe and reliable operation
Abrupt Stoppage of Turbine Rotor, Running on Barring after Major Overhauling
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Reddy, Ranga; Reddy, Ravi S.
Case Study 15: This case study is about a typical experience where a steam turbine, which was running at 100 RPM on barring (turning) after overhaul, stopped abruptly and the rotor was found to be seized. The case study is about this incident and the external factors influencing the turbine rotor seizure, from 100 RPM to zero RPM in less than 5 seconds, its root cause and the rectification activities.
Accurate Estimation of Start-Up Pulsating Torque of Direct On Line Synchronous Motors Driving Compressor Trains
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Meucci, Francesco; Spolveri, Niccolo; Donati, David; Del Puglia, Stefano
In a compressor train driven by fixed speed synchronous motor (>17MW) was discovered a potential torsional problem on the input shaft of the hydraulic variable speed gear during the start-up phase when only low speed shaft line is engaged. It was due to high motor excitation torque crossing the 1st torsional critical speed during startup causing a very limited numbers of train startups (1400) versus project requirements (5000). Supported by API 617 (8th edition), the motor excitation air-gap torque during startup has been analyzed considering electrical system characteristics that influence the effective voltage drop at motor terminals. A more realistic analysis of the excitation confirmed the correctness of the shaft line design avoiding any redesign and impacts in the projects execution.
Adapting Compression Equipment to Accommodate Declining Well Pressures and Ensure Overall Efficiency in Mid/Late Field Life
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Gunn, Ben; Kurz, Rainer; Bender, Jonathan; Hayes, Joel; Hai, Yakin R.; Utami, Aning Restu
Case Study 9: Compression systems are designed for the governing process conditions. In the Oil and Gas industry, these conditions are often dynamic and a function of reservoir or field characteristics which have varying head and flow rate requirements throughout the field life. The main application objective when designing a gas turbine driven centrifugal compression solution to suit these applications, is to maximize efficiency while minimizing the requirement for additional package modifications or major capital works in mid to late field life. This presentation shows how these objectives were achieved for a case example in South Sumatra, Indonesia where an onshore gas field, feeds a localized gas plant that requires front end compression.
Advancements in Mechanical Sealing - API 682 Fourth Edition
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Huebner, Michael; Buck, Gordon; Azibert, Henri
API 682 is the leading document for mechanical seals in petrochemical, chemical, and pipeline services worldwide. It has combined the aspects of seal design, testing, standardization, and applications to provide the users and OEMs alike with a common source of information for mechanical seals. As seal technology has advanced, the standard has expanded to incorporate new seal designs, materials, seal selection guidance, and piping plans. The current edition, the Fourth Edition, was published in May of 2014 and is now available for purchase. This tutorial will cover the major changes introduced in the Fourth Edition.
Application and Design of Integrally Geared Compressors
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Wygant, Karl; Bygrave, Jonathan; Bosen, Werner; Pelton, Rob
Tutorial 7: Integrally geared compressors (IGC’s) are common in plant/instrument air service as well as air separation applications, and continue to gain acceptance over a wide range of other applications. An IGC can achieve high efficiencies but is subject to complicated mechanical interactions. As a result of the mechanical complexity: design engineers, application engineers, and even end users of IGCs benefit from a diverse and in-depth knowledge of all of the engineering principles applied to arrive at an efficient machine with robust operating characteristics. This paper emphasizes the practical aspects of sizing and selection criteria for an integrally geared compressor for a range of applications and promotes a thorough understanding of practical limits of this type of compressor. Underlying aerodynamic principles are reinforced and limiting design aspects such as: gear tooth loading, lateral rotordynamics, bearing surface speed and loads, low- and highcycle fatigue of impeller blades are all iterated to find compromises to meet the demands of each application. Understanding the application and applying appropriate design limits is essential to meeting ever more challenging installation requirements.
Application of Dynamic pressure-balanced Seals in a Multi-stage Centrifugal Compressor
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Stiles, David; Justak, John; Kuzdzal, Mark; Miller, Harry; Sandberg, Mark; Rohrs, Charles
Test results for an ASME Power Test Code 10 (PTC) Type 1 test of a 4,500 psia (310 Bara) discharge pressure gas lift centrifugal compressor outfitted with dynamic pressure-balanced seals at the impeller eyes; shaft interstage and division wall locations are presented and compared to the same testing with conventional labyrinth seals. Both aerodynamic performance and rotor dynamic stability, obtained via operational modal analysis (OMA), are presented. A client’s motivation, along with the design and testing of dynamic pressure-balanced (DPB) seals for turbomachinery are also presented in this paper. With the DPB seals installed the test results indicate 2.8 percent lower power was required for the same head level across the entire range of inlet flows and pressure ratios, when compared to the same testing with conventional labyrinth seals. Rotordynamic stability, obtained via operational modal analysis (OMA), showed the dynamic pressure-balanced (DPB) seals exhibited log decs similar to standard labyrinth seals across the entire range of flows and pressure ratios. The foregoing demonstrates both the aerodynamic and mechanical/rotordynamic integrity of the dynamic pressure-balanced seals for oil and gas, turbomachinery applications.
Applying Upstream Pumping Sealing Technology for high corrosive fluid – Improve Reliability & Operating Cost
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Yanhui, XU; FitzGibbon, Gibbon
This is a mechanical seal upgrade case study about applying advanced upstream pumping technology instead ofconventional tandem seal arrangements with external flushing in high corrosive fluid pump seal applications in order to improve equipment reliability and minimize the operating cost
Atypical Results from Improperly Sized & Charged Pulsation Dampeners
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Poerner, Nathan; Broerman, Eugene; Souther, Tappan; Cook, Trenton
At a facility with four quintuplex pumps, pulsation dampeners were being used to control pulsations in the discharge line. However, the initial dampeners were both undersized and undercharged for the application. As a result, in addition to some typically expected results, including high pulsations and frequent failures of the internal bladders, the effective volumes of the dampeners and lengths of piping in the system set up an acoustic natural frequency that caused significant safety concern and limited system operability. This natural frequency was in a range that could be excited by the pumps such that the presence of the dampeners in the system was actually causing even higher pulsation levels. This paper will look at the troubleshooting efforts including field testing and acoustic simulations. Results from the modified system will also be discussed.
Bad Actor Elimination in Pumps
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Bhat, Vasanth; Suthan, Thangavel
Case Study 12
Base Plate Corrosion and Premature Bearing failure in RO Pump
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Subramanian, Moorthy
On 19th Aug 2017, abnormal noise noticed from RO (Reverse osmosis) Membrane Feed pump coupling area. Checked the vibration for pump & motor and found very high vibration at Pump Drive end. The vibration level at Pump DE Vertical recorded as 4.5 mm/sec (Allowable: 3 mm/sec Max.) Pump was stopped to identify the reason for the high vibration and abnormal noise. Checked the alignment and found the vertical offset at motor end coupling is 0.8 mm higher than the pump end. Customer has tried to perform the alignment with their own maintenance team and found there is no shim at motor foot to do the necessary correction. Customer has approached OEM Service team.
Benefits of Installing Restrictive Orifice Plates on the Suction of Reciprocating Pumps: 1D Pulsation and CFD Studies
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Crowther, Paul; Chen, Zixiang; Ijeomah, Cajetan; Grose, Jordan
It is well understood that static pressure at the inlet of reciprocating pumps, quantified typically by Net Positive Suction Head Available (NPSHA), must be sufficient to avoid cavitation in the pump suction manifold and chamber. In an effort to conserve NPSHA, pump designers generally rely on rules of thumb that resist the addition of pressure drop elements such as restrictive orifice plates, choke tubes and line-size reductions to the inlet piping of all pumps, including reciprocating pumps. Another design consideration of reciprocating pumps is the generation of pressure pulsations due to pump piston and valve motion. Uncontrolled pulsations can result in cavitation and vibration-related fatigue failures. In many cases, pressure drop elements are required to control pressure pulsations. Can there be a balance between the pulsation control benefits of pressure drop elements and the need to meet NPSHA? This paper is of interest to designers and engineers working with reciprocating pump installations. It aims at challenging industry resistance to using pressure drop elements in the suction piping of reciprocating pumps by, first, outlining the virtues achieved in terms of pulsation and vibration control, and second, presenting results from numerical simulations (one-dimensional pulsation and detailed CFD modelling). Recent field data from a quintuplex pump installation were used to validate the 1-D pulsation model. The results show that well-designed orifice plates, and other pressure drop elements, are beneficial for reducing pulsations and cavitation risks; and can be used in the suction piping of reciprocating pumps.
Blade Failures on an Axial Compressor by Unexpected Gas Compositions
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Schwarz, Marco
A fifteen stage axial compressor including a bleed extraction was subject to a major overhaul after nearly 20 years of trouble free operation. Shortly after recommissioning and resumption of the production the compressor faced three major failures within two weeks. A root cause failure analysis was conducted and revealed that the process plant start-up procedures caused gas compositions which deviated strongly from the design conditions. The valve designs as well as the available control parameters were not able to protect the compressor from off-design operating conditions. For future compressor failure prevention, the process start-up procedures were adapted and the existing control parameters/logic was upgraded. The new control logic reacts to the transient process behaviours during start-up by continuous harmonization of the safety valves.
Carbon Foot Print Reduction Techniques with Rotating Machinery
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Bhat, Vasanth M.; Aaron, Quek Ser King
Tutorial 8: Global Environment concerns and need for more optimized production costs is driving all industries including Oil & Gas to look at more ways to reduce energy consumption without compromising on plant throughputs. This is specially challenging for older units to carry out modifications on existing assets and justify these with good paybacks for the capital investment needed. The article looks at the possible solutions available in this regard relating to rotating equipment and are illustrated with case studies to back these recommendations in most cases.
Case Study on Remote Diagnostics in Resolving Random Vibration on a Steam Turbine
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Ganesh, R. Sankar; Iqbal, Muhammad Zeeshan
Case Study 7: This case study narrates an incident of random vibration spikes which occurred in year 2014 on one of the steam turbine bearings of a propane refrigeration compressor train. The random vibration spikes caused the turbine high vibration to trip leading to a train shutdown. This case study outlines how the random vibration spikes were successfully diagnosed through remote monitoring center, the root cause for the high vibration trips, and finally how it was mitigated. The case study also discusses lessons learned with respect to the discovery methodology using expert system available at site, and the importance of monitoring key operating parameters.
Case Study on Resolving High Vibration Issue of a Centrifugal Compressor at an Offshore Platform
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Sharma, Amit; Ganesh, Sankar
Gas Injection Compressors are critical for offshore oil production facilities. A compressor downtime lowers oil production. This case study is about a Gas Injection Compression train at an offshore platform in the Middle East. This case study focuses on how the gradual increase in vibrations was successfully diagnosed, pinpointing the root cause for the high vibration, and finally how it was resolved. The Compression train is equipped with an online vibration monitoring and protection system in addition to a condition monitoring software that was used to diagnose the issue.
Catastrophic Failure Diagnosis with Modal Analysis of Generator Endwindings
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) de Guarda Matos, Danilo
This failure lead a root cause analysis and a series of investigations that was taken place in a similar design unit deployed at a different site. This paper will describe the bump test and modal analysis procedures and results that were carried out on the end of all coils of the stator winding in the sister unit of the failed 360MW generator which lead to conclusions that were crucial for the determination it´s failure root cause.
Centrifugal Compressor Surge Control Systems - Fundamentals of a Good Design
(Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Botros, Kamal; Hill, Steven; Grose, Jordan
Lecture 2: Many facilities employ two or more centrifugal compressors, operated in either series or parallel configurations. An accurately designed surge control system that includes multiple compressors with the associated piping systems is a vital element of a facility’s design and ongoing operational integrity. The design must ensure compressors are not subjected to damaging fast dynamic events leading to large capital costs and significant down time for operators. Examples of such fast dynamic events are those following emergency shutdown (ESD) or fast stop of one or all compressor units in a station. Typical studies are not accurate enough to capture the complex interactions leading to catastrophic events, especially for complicated system arrangements. This paper introduces three methods of surge control analysis that can be conducted to assess the effectiveness of any surge control system design to prevent the compressor from surge. The first method utilizes the perturbation theory to relate the compressor deceleration and the resulting drop in its flow and head to determine the elapsed time that the compressor can stay out of surge before the surge control system brings about enough positive flow to prevent the unit from undergoing deep surge. The second method is simpler, and is based on a dimensionless number, called the inertia number, which combines the salient parameters from the dynamic equation between the fluid energy and that of the compressor rotor inertia to determine, as a first cut check, if the surge control system is adequate. The third method, which is always recommended, and is based on solving the full gas dynamic partial differential equations (PDEs) in spatial and temporal domain, which describe the true dynamic characteristics of the flow through the various piping elements, the compressor itself, to provide much more accurate predictions of surge control system behavior during fast transient events. Comparisons are made to field measurements to provide model validations, and an example application (Case Study) of three units operating in parallel. The first two (Units 6 and 7) were existing in a compressor station, while the third (Unit 8) was an add-on. The addition of Unit 8 meant a number of station layout modifications, which included: re-wheeling of Units 6 and 7 (i.e., change the compressor impellers); adding after gas cooling; and relocating the anti-surge valves downstream of the coolers to allow for both hot (fast stop) and cold recycle (anti-surge) capabilities. Due to the addition of equipment and significant reconfiguration of station piping and valves, a dynamic surge analysis on Units 6, 7, and 8 was required to determine whether the existing anti-surge and fast stop valves were adequately sized and whether the anti-surge valves could be relocated downstream of the gas coolers. A new fast stop recycle system was added along with Unit 8, which also needed to be adequately sized. Further complications arose from the fact that Unit 6’s anti-surge valve configuration differs from that of Unit 7 and that Unit 6 has twin recycle valves jointly serving as anti-surge valves with a single fast stop valve while Unit 7 has a single anti-surge valve and a single fast stop valve.
Centrifugal Compressors 101: Part 1
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Kuzdzal, Mark; Koch, Jay
Reciprocating and centrifugal compressor similarities/ differences -How do they work? (Potential Energy, Kinetic Energy, PE, KE, …) -History of compressors – Timeline, major advances – Configurations, straight-through, back-to-back, compound, side streams, double-flow -Markets served -Pressure containment – Case – Nozzles and flang -Selection Process – Aerodynamic Selection – Mechanical Design – Rotordynamic Design Impellers – Design Basics -Stationary Aero Components – Inlet, inlet guide – Diffuser, vaned and vaneless, LSD – Volute and collector – Return bend / Return channel -Compressor Performance – Nomenclature – Impact of Operating Conditions – Internal Leakage – Surge Control -Rotordynamics – Critical speed maps – Synchronous unbalance response – Stability, log decrement – Damper seals – Bearings, seals – TP, Sleeve, magnetic – Squeeze film damper – Steady state and transient torsional -Stress analysis – Impeller dynamics -Acoustics -Seals – Gas seals – Oil film seals – Laby
Centrifugal Compressors: Operation and Maintenance, Advanced Design, Wet and Sour Gas Operation
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Baumann, Urs; Baldassarre, Leonardo; Gupta, Manoj; Hataya, Takeshi; Konomi, Shin; Kumar, Arun
Topics Outline: • Meeting current rotordynamics stability standards • High flow coefficient/mach number impellers • Low flow coefficiens/high pressure impellers; Reynolds correction Complicated high pressure gas properties. E.g., CO2, acid gas, H2S • Testing of the equipment • Modern manufacturing/forming methodologies • Simulation and dynamic process modeling • Handling of Chlorides in sour/acid gas applications, including piping; end-user strategies Hermetically-sealed compression