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
A comparison of Operating Deflection Shape and Motion Amplification Video Techniques for Vibration Analysis
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Price, Stephen M.
The Operating Deflection Shape (ODS) technique that was derived from Experimental Modal Analysis has served well to assist users in quantifying vibration amplitudes, determining vibration mode shapes, looseness between components, the most effective location and direction to add stiffness, and identifying cracks in beams and foundations. A new technique involving amplified video has now become accepted that promises to do much the same with considerably less effort. However, each technique has its own range of applicability. Examples from the field using both techniques are provided to help users evaluate the relative strengths and weaknesses of the techniques.
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.
ADAPTATION OF REMOTE AND AUTONOMOUS OPERATION (RAO) FOR ROTATING EQUIPMENT OF PETRONAS FACILITIES
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Sabri, Ir Dr Harris Abd Rahman; A Malek, M Helmi; Khaliq, Usaid
The Oil and Gas industry is increasingly facing with more complex and hazardous operations. This is resultant from integration with a more complex feed and product properties as well as requirement for operation in harsher environment. At the same time, a much stronger Environmental regulation is currently enforced which demands strict adherence and compliance by all Operating Assets/Facilities. At the same time, technology has caught up rapidly in the last few years. More industries have started to embrace automation as a safety and productivity enabler and as a critical factor in running business and operation. The center of attention to this shift is automation of Rotating Equipment covering broad range from Turbomachinery down until a Potable Water Pump. Network communication enhancement via 5G technology has allowed remote operations and control technology able to be safely deployed. The new norm of Remote and Autonomous Operation (RAO) via Artificial Intelligence, Machine Learning, Digitalization effort as well as Digital Twins are also increasingly being adopted to allow for better performance monitoring, remote trouble shooting, predictive and prescriptive ability for Rotating Equipment. As proven in many industries and sector, PETRONAS have also successfully embarked on remote and autonomous operation journey for its Rotating Equipment fleet which will add clear value: it can improve safety, increase production efficiency, and lower maintenance costs. Although, implementing autonomous systems may also expose and presents new challenges such as cyber security and safety risks, the obvious advantage supersedes the risk which needs to be managed accordingly. This paper explains the challenges, the lesson learnt and PETRONAS approach in adapting RAO for Rotating Equipment.
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.
Additive Manufacturing of Cryogenic Pump Impellers
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Bauer, Derrick
Additive manufacturing has been utilized in an increasing number of applications for many different types of services. Cryogenic pump impellers can be manufactured to ASTM F3318 for AlSi10Mg in the HIP + T6 condition through Direct Metal Laser Sintering (DMLS) which achieves mechanical properties which are improved upon standard A356.0-T6 impellers. The tensile strength, yield strength and ductility of the material exceed that of the cast impeller. High cycle fatigue testing as shown that there are no reductions in the fatigue endurance limit, both at room temperature and at cryogenic temperatures. The dimensional tolerances of the as-printed surfaces can be maintained in comparison to cast impellers, and surface finish obtained on the as-printed surfaces can match the surface finish of traditional sand cast impellers. Non-destructive evaluation performed on the impeller through both surface inspection and volumetric inspection can meet or exceed the inspection requirements that are applied to cast impellers. Additive manufacturing of cryogenic pump impellers can be utilized to improve the lead time, making it ideal for service and replacement parts applications.
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.
ADVANCES IN AMMONIA COMBUSTION CHEMISTRY AND NH3 SENSING USING LASER DIAGNOSTICS
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Alturaifi, Sulaiman; Mathieu, Olivier; Petersen, Eric L.
Ammonia (NH3) is a promising alternative carbon-free fuel. For this reason and others, significant research is directed towards studying NH3 especially pertaining to its chemical kinetics. A brief review of the literature on ammonia combustion chemistry is provided in this paper, with emphasis on the studies related to fundamental reaction kinetics at elevated temperatures. Until recently, NH3 was never measured using laser absorption spectroscopy to study its chemical kinetics. This recent NH3 measurement was conducted by the authorsâ€™ group using a newly developed laser absorption diagnostic that probes the v2 fundamental band of NH3 in the mid-infrared near 10.4 Î¼m. The present study utilized this recently developed NH3 diagnostic to highlight its capabilities and potential future use for studying ammonia combustion chemistry and also as an ammonia sensor for practical applications. The laser was operated using two methods: a scanned-wavelength method to measure the absorption spectra of NH3-containing mixtures, and a fixed-wavelength method to measure NH3 time histories behind reflected shock waves. The scanned-wavelength method was used to determine the NH3 mole fraction in multi-component gas mixtures; such a method presents future promise when the accurate determination of NH3 in a sampled gas is needed. The fixed-wavelength method, coupled with a shock tube, was used to follow NH3 time histories during the oxidation of NH3/O2 in Ar; such a method shows promise for studying the chemical kinetics of ammonia.
AN OVERVIEW OF MACHINERY IN ENERGY STORAGE AND HYDROGEN APPLICATIONS
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Allison, Timothy; Smith, Natalie R.; Rimpel, Aaron M.; Brun, Klaus
Decarbonization of electric power infrastructure requires the development of cost-effective, sustainable, and reliable energy storage technologies that are capable of many Megawatts or Gigawatts of output and long storage durations potentially spanning days, weeks, and months. These technologies would absorb power from the grid during periods of excess renewable generation, and release the stored energy to generate power when renewable sources are unavailable. The first part of this tutorial introduces the history of energy storage technologies, general requirements for energy storage applications, and challenges with grid-scale electrochemical batteries that drive the development of machinery-based systems for energy storage. There are many existing or developing machinery-based energy storage systems to fulfill this need. These systems include various pumped hydro technologies, flywheels, compressed air, gravitational, liquid air, thermal energy storage including pumped thermal, and various thermochemical technologies such as hydrogen, ammonia, synthetic natural gas, or sulfur. A comprehensive overview of all of these technologies is provided including basic working principles, role/requirements of turbomachinery, hybridization with existing power generators, current state of development including pilot/demo activities, capabilities relative to other technologies, and research & development needs for system improvements and commercialization. In particular, the authors will discuss hydrogen machinery including an overview of hydrogen impacts on compression and combustion in machinery for pure hydrogen and blended hydrogen applications.
ANNULAR CLEARANCE GAS SEALS: MODELS AND MEASUREMENTS FOR LEAKAGE, FORCE COEFFICIENTS AND THEIR EFFECT ON ROTOR STABILITY
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) San Andres, Luis; Delgado, Adolfo; Yang, Jin
Turbomachinery seals are engineered to maintain efficiency and power delivery by minimizing leakage. Seals also appreciably affect the system rotordynamic behavior due to their relative position within a turbomachine. The tutorial reviews the experimental record on gas seals as published in the 21st century1, and gives insight on the physical models predicting leakage and dynamic force coefficients. Simple leakage and transport equations are the basis for bulk flow models (BFMs), whereas computational fluid dynamics (CFD) software relies on the solution of the Reynolds-Averaged Navier-Stokes equations (RANS) with an appropriate turbulence flow model in a multi-million node mesh count. Leakage data for seals with nominal clearance (Cr) include labyrinth and interlocking labyrinth seals, damper seals such as honeycomb (HS), pocket damper seals (PDS), conventional and hybrid brush seals, and the advanced (clearance control) HALO seal. A flow factor characterizes the seals as a single-knife (restriction) with an effective clearance (Ce). The extensive comparisons of leakage, measured and predicted, show that engineered seals have an effective clearance Ce/Cr = 0.30 - 0.40, and which is not a function of either inlet pressure, exit pressure, rotor speed, or even actual clearance. The finding attests to the well-understood nature of the fluid flow through the seals. Both BFM and CFD models accurately predict seal leakage. Seals produce reaction forces due to shaft lateral displacements, and with stiffness and damping coefficients characterizing a seal dynamic response. A direct stiffness (K) produces a centering action whereas a direct damping (C) dissipates mechanical energy. A cross-coupled stiffness (k) arises due to shaft rotation dragging the gas around the seal circumference. In general, the force coefficients of a gas seal are frequency (ï�·) dependent. A positive k (>0) decreases the seal effective damping Ceff = (C-k/ï�·), hence degrading the stability of the mechanical element. k is proportional to the gas circumferential speed entering the seal; hence, adding either a swirl-brake or shunt-injection with (excess) gas flowing in the direction opposite to shaft rotation helps to diminish k (ïƒ 0 or negative). The tutorial reviews multiple examples of normalized stiffness and damping coefficients for various seal types including uniform clearance seals, LS, and damper seals (HS and PDS). LS with teeth on the rotor surface are notorious for producing large k. Poorly designed LS, installed as either balance piston seals or impeller eye seals, are the cause of many rotordynamic instability fiascos. Damper seals produce direct K and C orders of magnitude larger than those from conventional LS. Damper seals in conjunction with a swirl brake also produce very small k; hence, effectively removing a concern on rotordynamic instability. Past are the days when LS, known bad actors, were the only choice effectively sealing the stages in a turbomachine. Incidentally, damper seals, honeycomb and hole-pattern seals in particular, can produce a large centering stiffness (K>>0 ) that makes a balance piston seal in a back-to-back centrifugal compressor to act as a third bearing, hence rising the first natural frequency of the rotor system. Although both the BFM and CFD models are good to predicting leakage, they fall short to replicate the experimental force coefficients of damper seals. At times, C is accurately predicted while K or k are not, or vice versa. The predictive methods still need improvement, hence the need of constant and continuous experimental verification. Differences between predictions and measured force coefficients are likely due to the lack of fidelity in reproducing complex unsteady (highly turbulent) flows whose dynamic pressure acting on the rotor produces the seal reaction force. Derived from the comprehensive experimental results, the review concludes by advancing rules of thumb to estimate the range of expected direct stiffness (K) and effective damping (Ceff) applicable to damper seals. Unlike experiences in the past century, damper seals offer a remarkable opportunity to control the leakage and tailor the rotordynamic performance and stability of modern rotating machinery.
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.
Application of Polycrystalline Diamond (PCD) Bearing for Reactor Circulation Pump
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Lakshmanan, Praveen; Vengurlekar, Ashutosh
The axial flow loop reactor pump installed in a polymer unit facilitates slurry circulation in the reactor. The pump is installed with triple mechanical seal having API seal flushing plans 32, 53C and 52. The seal cartridge contains a radial bearing for shaft support to ensure stability on the cantilevered pump design. There have been multiple failures in the past with low seal MTBF. The failure analyses conducted indicate similar failure mechanism- seal support bearing failure leading to primary seal leak and subsequent shutdown. The failure mechanism has been attributed to skidding and sliding wear on one of the rows of rollers in the bearing. The skidding/sliding is caused by the insufficient load on one of the rows of rollers caused by axial misalignment between the inner and outer race. This misalignment can happen during transients when thermal growth differences require outer race to slide inside the seal housing fit. The lubrication of the bearing and sliding joint can be further impacted by seal oil contamination stemming from seal face geometric instability allowing reverse flow of process across seal face. This process contamination and viscosity loss can cause rapid deterioration of the bearing due to poor lubrication. To address these vulnerabilities, a Polycrystalline Diamond (PCD) bearing is installed to replace existing spherical roller bearing for the rotor support system inside the mechanical seal cartridge. Also due to PCD bearing design, the bearing is less sensitive to lubrication issue caused by C3 ingress into seal oil. This article presents a summary of investigation around the root cause of multiple seal failures in a specialty pump application and â€˜fit for purposeâ€™ mitigation taken as a result of investigation along with the capabilities of PCD bearing technology to tackle a design with inherent vulnerability.
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.
BEARING LOAD ANALYSIS OF RECIPROCATING PISTON COMPRESSORS
(Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Fritz, Bernard; Baldussu, Alessandro; Brandl, Andreas
Many problems in todayâ€™s industrial environment require smart modeling assumptions in order to make them numerically accessible with an acceptable amount of effort. This case study shows how a field problem (main bearing failures) is turned into a numerical model: we present a bearing force analysis of a 5-throw reciprocating compressor with severe problems on its third main bearing. Inertial and gas-dependent forces are calculated. The crankshaft is modeled as a uniform beam; its load-dependent deformation and the resulting bearing loads are estimated based on Clapeyronâ€™s three-moment equation with the assumption of zero bearing clearances. The resulting calculation time is < 1s for a 360-degree load cycle, allowing detailed studies that yield conclusive results: polar load diagrams clearly confirm that the problematic bearing is exposed to the highest loads in operation. The short calculation time allows for parametric studies investigating the effect of lower reciprocating masses, partial load conditions, counterweights, different crankshaft designs, or combinations of the above.
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.