Advancements in Pulsation Control Technology
Eugene L. (Buddy) Broerman, Marybeth Nored & Robert J. McKee, Southwest Research Institute
Pulsations at cylinder valves that are associated with the cylinder nozzle resonance and residual, low frequency pulsations in the piping system beyond the filter bottles are the main pulsation problems that were identified at the start of the GMRC ARCT (Advanced Reciprocating Control Technology) Pulsation Control Research Project. Low or no pressure loss concepts were conceived during the research project that would reduce, and in some cases significantly reduce, the pulsations associated with those two main pulsation issues. Simulations were developed and prototypes were tested in an effort to evaluate and further develop the pulsation control concepts. At GMC2006, current progress was presented regarding the project prototype development. All the prototypes presented showed promising pulsation control characteristics. Some prototypes had characteristics that were more promising than others. The virtual orifice (VO) showed significant reduction of the cylinder nozzle pulsations without the cost of the pressure losses typically associated with an orifice. The tunable side branch absorber (TSBA) nearly eliminated low frequency pulsations over relatively large speed ranges. Advancements of those prototypes, other prototypes, and new concepts for the current year are presented in this paper.
Subjects: Uncategorized
Advances in Fundamental Understanding of the Dynamic Sealing Action in Packing Systems
Dr. Tino Lindner-Silwester, Hoerbiger Innovation & Technology
It is well-known that the achievable lifetime of a dry-running piston rod packing seal is significantly dependent on the temperature level the sealing elements are exposed to during operation. Thus, a deeper understanding of the various thermo-physical processes governing the non-lube operation of a packing is crucial for (a) assessing the major influencing factors that give rise to the current application limits of dry-running packings and (b) developing improved packings capable of coping with demanding applications. The approach discussed is targeted at gaining that fundamental understanding of dry running compressor packing, consisting of the creation of a novel theoretical model that accounts for all the complex mass and energy transport phenomena, the design and creation of a test compressor (“multipurpose test compressor”, MPTC) which can be operated and monitored with advanced sensing instrumentation during operation and fundamental investigations into transfer film phenomena, heat transfer and gas transport may be made. In this paper, the simulation model is presented and its predictions are compared to measurements taken on the test compressor.
Subjects: Uncategorized
The Advantages of Modern Slow Speed Compressors for the Gas Transmission and Gas Storage Market
Martin Hinchliff
The Advantages of Modern Slow Speed Compressors for the Gas Transmission and Gas Storage Market
Subjects: Uncategorized
James McCarthy, Innovative Environmental Solutions
This annual session on air regulatory issues will cover the status, content, and potential impact of new U.S. EPA and State air regulations affecting gas industry facilities.
Subjects: Uncategorized
Analysis of a Variable Geometry Diffuser Turbocharger to Increase Engine Operating Flexibility
Kirby Chapman, Ali Keshavarz & Chris Erickson, Kansas State University NGML
The operating range of a centrifugal compressor is limited by the surge and choke flow conditions that defines its operating range at low and high flow rates respectively. Fitting a conventional full length vaned diffuser creates a throat and the increased blockage reduces the flow range. In addition, incidence effects at low flow rates can have an adverse effect on the surge condition. In general, conventional vaned diffusers lead to an improvement in efficiency and pressure ratio over that possible with a vaneless diffuser; the operating range, however, is reduced. The deficiency in the operating range can be eliminated by the adoption of variable geometry diffusers. In this study, performance of a turbocharger centrifugal compressor for different diffuser vane setting angles was investigated numerically and experimentally, with a focus on experimental results. The numerical simulation results showed that the diffuser vane setting angle influences compressor operating range and its efficiency. Higher pressure ratio and a wider high efficiency island were achieved when the vanes were moved 10° closer to the impeller in comparison to its baseline vane settings. To verify the computational results, a redesign on an existing ET-18 turbocharger was done. The redesign allows the diffuser vanes to rotate in real time while operating the turbocharger throughout its speed range. The test data of the VGT turbocharger show a significant improvement in the operating range at design speed or higher while rotating the vanes closer to the impeller. The draw back is a small loss in pressure and isentropic efficiency. While turning the vanes away from the compressor blade, the pressure ratio increased but the operation range was narrowed. This paper reports the quantified results of the VGT tests, and clearly shows how the turbocharger can be used to expand the engine operating range.
Subjects: Uncategorized
Analysis of High-Speed Engine Valve Vibrations Using Statistical Methods
Fred Oliva & Bob Webber, Dynalco, Division of Crane Corp.
High-speed engines used in natural gas gathering applications have been shown to have a history of power valve failures. This is especially true for exhaust valves, due to the high temperature environment to which the valve is exposed. A methodology for analyzing valve closing events using statistical techniques has the potential for practical and effective prognosis of valve failures. Methodologies for analyzing vibration signatures of a valve closing event are discussed. This includes an ongoing investigation into observed vibration variability and its correlation to failure modes. Statistical techniques are used to analyze long-term vibration patterns. Additional topics covered are valve vibration signatures as a function of engine load and RPM. This paper will present first-order differences between a nominally healthy valve and one that is approaching failure based on statistical analysis. Since this is an ongoing investigation, the conclusions presented are considered preliminary and will lead to additional research.
Subjects: Uncategorized
Markus Dettwyler, Kistler Instrumente AG/Greg Beshouri, Advanced Engine Technologies Corp./ Eric Dufur, ScavangeTech/Simon Johnson, Kistler Instrument Corp.
Traditionally the analysis of the operating condition and balance of a large bore gas engine in the field is performed on the basis of simple statistical analysis of combustion pressure. In other industries additional sensor installations and analysis methodologies are often used to perform the same task. These modern analysis techniques have not regularly been applied to the large bore gaseous fuelled engines typically found in the US Gas Pipeline Industry. This presentation will focus on some of these methods to better understand combustion instability. These include intake and exhaust manifold pressure measurements as well as deeper analysis of the combustion pressure trace. Within PRCI’s ERLE 1c Project, extensive measurement data on combustion pressure as well as on intake and on exhaust pressure has been collected. Kistler provided extended sensor equipment and support to that project. The collected data provides the unique opportunity to investigate pressure signals and to correlate calculated parameters to combustion instabilities on these engine types. A variety of different operating conditions were included reflecting stable and unstable operation. The team then analyzed thousands of cycles in the search of sources and consequences of instability on a cylinder level basis. Some points of detailed focus are: associated sensors and instrumentation; testing program and selected operating conditions; statistics and data analysis methods including basic thermodynamic values; presentation of manifold pressure patterns and combustion parameters associated to instabilities; discussion of results and recommendations. The paper will provide an insight into the combustion processes and associated stability issues in large bore gas engines under real operation and will help to improve operational conditions of these kinds of engines. As a continuation of the presentations given at GMC 2004 to 2006, this paper is focusing on possible evaluations of engine operation stability of gas engines in the field.
Subjects: Uncategorized
Application of On-Line Acceleration & Cylinder Pressure Measurements
John Kitchens & Brian Howard, GE
Portable condition monitoring systems for reciprocating compressors have long provided cylinder pressure and other measurements
on reciprocating compressors. By itself, cylinder pressure enables diagnostic tools such as pressure versus volume (PV) curves that allow the condition of the sealing elements inside the cylinder to be understood. It has also been understood that combining the cylinder pressure, rod load and crosshead acceleration curves allows one to assess the condition of the crosshead pin, piston rod to crosshead connection piston to piston rod and liner. On-line systems with similar measurement capabilities have gained commercial acceptancein recent years. These systems consist of a variety of transducers, electronic protection/data collection hardware and data analysis an trending software. Unlike portable systems, the transducers must be permanently attached to the compressor, the hardware installed at the compressor, often in hazardous areas, and the software integrated into the corporate IT structure. This paper presents a short tutorial on the economic justification, selection, design and installation of on-line condition monitoring systems for reciprocating compressors. A series of short case histories will be included to show the impact of correctly selected and installed condition monitoring systems on reciprocating compressor economics, operation and reliability.
Subjects: Uncategorized
Applying Asset Management Measurement Techniques in a Natural Gas Transmission Compressor Station
Bob Webber, Dynalco, Division of Crane Co.
This is an ongoing project that hopes to provide the gas industry with the methods for making four critical measures to allow Asset Management to be accomplished in a meaningful and measurable way. The four measures are economic impact, life cycle, economic opportunity and risk for each machine in the fleet. Millions of dollars and man-hours have been invested in operating data either crawling in on hand generated logs or streaming in via SCADA. Technology and techniques have existed for years thatwould allow operators to use this mountain of data to get near real-time information. Actual real implementation of such an “integrated system” and the difficulties and results encountered over a two-year period will be discussed here. The operating characteristics of these four units were clearly not understood prior to getting real-time information. Many control system issues were uncovered. This integrated approach employs both existing and newly installed monitoring devices. The real-time calculation of “Profit per Brake Horse Power Hour” and the use of BWR to obtain real time HP/MM are just two of the many techniques used and developed during this period. The implementation of systems that are capable of boiling the mountains of data that is available at modern compressor stations to useable and actionable information is possible today and has implications in the millions of dollars to transmission companies willing to make the leap.
Subjects: Uncategorized
George Mathai, Dominion/Dwayne Hickman, ACI Services, Inc./Ron Miller, Basic Systems, Inc.
Modern PLCs offer the computing power necessary to implement complex control strategies that can incorporate multi-unit supervisory station control as well as individual unit control methodologies based on load and/or flow. When controlling a reciprocating compressor, it is critical that the PLC is able to model unit loads and flows, select stage and optimum load steps, handle curve-crossings, and stay out of operating areas that can lead to serious issues such as rod loads, pin non-reversals, low volumetric efficiencies, high discharge temperatures, and blow through. When properly implemented, these strategies can help maximize the desired performance criteria (flow, fuel, emissions, safety, etc.), while protecting the unit from exceeding its design limits. However, when not implemented properly, a unit under automated control can experience problems that can result in unstable control, and/or a reduction of unit availability. This paper details methodologies for controlling reciprocating compressors using either PD-based approaches or deadband-based approaches. Various issues typically experienced with controlling reciprocating compressors are discussed and possible solutions detailed. Moreover, general control code and flow charts are presented that cover how to effectively control most natural gas services (production, gathering, pipeline, storage, and injection/withdrawal).
Subjects: Uncategorized
Basic Thermodynamics of Reciprocating Compression
Greg Phillippi, Ariel Corporation
This short course is intended to provide the attendee a review of the basic thermodynamic principles of compression utilizing a reciprocating compressor. This will include discussions of the pressure-volume diagram, volumetric efficiency, capacity, and adiabatic valve loss and friction horsepower. In addition, the topics of varying conditions, gas analysis, temperature, pulsation, staging and end deactivation horsepower are reviewed.
Subjects: Uncategorized
Compressor Station Risk Reliability & Failure Mode Analysis
Thomas Moore, Kristopher Kozak & Klaus Brun, Southwest Research Institute
Most accidents and failures in compressor stations are not caused by a single incident of equipment malfunction or operator failure but are generally a result of a chain of events and errors that interact and/or accumulate to lead to a catastrophic failure. These failure events are extremely difficult to predict using the common single-degree-of-freedom analysis as they are caused by multiple factors and events that are systematically related to each other. This paper describes the development of methods and processes, similar to those commonly employed by the nuclear power and aerospace industries, to compute the risk, reliability, and failure modes within petrochemical related systems. The use of this type of analysis by design engineers, station operators, and risk assessment personnel is discussed. Analysis of actual pipeline compressor and pump stations has been performed and the results are presented.
Subjects: Uncategorized
Customer Driven Upgrades to the Engine Peak Meter
Paul M Odneal, Kistler Instrument Corp.
Customer Driven Upgrades to the Engine Peak Meter
Subjects: Uncategorized
Designing & Operating Compressor Stations When Fuel Costs are $5 to $10
William Couch & Mark Noall, El Paso Pipeline Group
Almost all of the older stations and many of the newer ones were designed using machinery and equipment specifications and “rules of thumb” that were developed over many years when station efficiency and fuel consumption took a back seat to reliability and desired equipment longevity. These stations were designed prudently when fuel costs were a dollar and fuel pass through contracts were the norm for most pipelines. However, today with fuel costs fluctuating between $5 and $10, a paradigm shift in station design and plant operation is needed to keep transportation costs competitive. A critical look at some of the old station design “rules of thumb” will be presented using today’s fuel costs to see if they pass the test of time or should be updated or tossed out. Several case studies of plant machinery, equipment and piping will be examined to determine if existing plants should be modernized, replaced or operated in a more efficient manner. This presentation will only touch on a few areas of compressor station design and operation; however, we hope it will become a catalyst for re-evaluating how compressor stations are viewed by the designers and operators in the context of overall pipeline operating costs.
Subjects: Uncategorized
Detection of Excess Emission Conditions for Rich Burn Engines Equipped with NSCR Reduction Systems
Gregg Arney, Southern California Gas Co./Dan McGivney, Eastern Municipal Water District/ Greg Beshouri & Geoff Ashton, Advanced Engine Technologies Corp.
In response to proposed amendments to South Coast Air Quality Management District (SCAQMD) Rule 1110.2 an Industry Stakeholder
Work Group conducted a series of field tests which investigated the ability of modern Air/Fuel Ratio Controllers (AFRC) applied to natural gas, rich burn engines with Non-Selective Catalytic Reduction (NSCR) systems to maintain control of engine emissions within the Best Available Control Technology (BACT) limits and detect out of control operations. Considerable effort was expended to field test various AFRCs on existing natural gas-fired rich-burn engines but none of the AFRC applied during the tests were able to consistently keep engine emissions in compliance, and engine load variations were particularly troublesome for the control systems. In addition, the alarm capabilities of existing AFRCs were not able to effectively detect all emission excursions. The tests found that proper programming of control parameters on each engine-AFRC system to be difficult and time consuming. The project demonstrated that existing AFRC technology diagnostics are not able to detect more complex out-of-compliance failure modes that can occur when the NSCR system drifts slightly outside the narrow window of compliance for SCAQMD limits. On the bright side, the data suggests certain parameters are closely correlated to emissions and these may be tapped for improved control or alarm algorithms. Based on these findings and other activities, it is expected that significant improvements in AFRC technology will develop in the coming years. While disappointing, the data provides hope that AFRC vendors can use such information to improve the performance and diagnostic functions of NSCR control systems.
Subjects: Uncategorized
Development of a Transient Fluid Dynamic Solver for Compression System Pulsation Analysis
Klaus Brun, Edgar B. Bowles & Danny M. Deffenbaugh - Southwest Research Institute
The Southwest Research Institute (SwRI) IPPS code has been successfully used in pulsation analysis for slow-speed compression
system design for the last ten years and more recently in the design of the new high-horsepower, high-speed compressor installations. The IPPS solver utilizes a solution algorithm of the transient acoustic wave equation in the frequency domain, which has been demonstrated to provide highly accurate results for compression system resonance frequencies and good agreement for pulsation amplitudes. However, the mathematical assumptions associated with solving the acoustic wave equations must lead to discrepancies in amplitude predictions as these equations are only a partial physical model of the actual transient fluid dynamics. A full one-dimensional representation of the governing transient fluid dynamic equations (called the Navier-Stokes equations) can provide a more thorough solution for the pulsating flow field and can provide more accurate pulsation amplitude predictions. This is particularly critical in the design of variable high-speed compressor systems, as for these applications complete resonance avoidance is impossible. Thus, SwRI decided to developa new one-dimensional time-domain Navier-Stokes model to improve SwRI’s prediction capabilities for transient compressor station manifold and piping systems. The resulting state-of-the-art piping pulsation analysis tool (called TPS) will lead to better design optimization capabilities for the pipeline industry. This paper describes the TPS solver development and validation testing.
Subjects: Uncategorized
Development of a Turbocharger Booster System
Kirby Chapman, Ali Keshavarz & Kyle Wolfram, Kansas State University NGML
In the natural gas industry a large portion of the engines used to compress the natural gas are lean burn engines. When these lean burn engines operate at low equivalence ratios, oxides of nitrogen (NOx) can be minimized. To operate at low equivalence ratios, these engines need a relatively high mass flow rate of air delivered to the intake manifold. One way to increase the mass flow rate of air to an engine is through the use of a turbocharger. The increased air mass flow rate, with a relatively constant fuel flow rate, reduces in cylinder combustion temperature which, in turn, reduces NOx formation. The downside is that the engine exhaust temperature is also lowered, which decreases the energy available to drive the turbocharger. Similarly, during the hottest days of the summer the density of air decreases which results in a lower air mass flow rate through the compressor and a lower trapped air mass inside the engine cylinder. The lower trapped air mass requires the engine to be de-rated, which reduced the gas throughput. This problem can be partially offset by the installation of a turbocharger booster system to increase the available energy at the turbocharger turbine inlet that then increasesthe power produced by the turbine to drive the compressor, One method to boost the energy available to drive the turbocharger is to increase the temperature of the exhaust before it enters the turbine via a relatively small dry low NOX burner. A turbocharger booster system was designed, prototyped, installed, and tested on the NGML’s turbocharger test and research facility. The test data show that the addition of a turbocharger booster system increased the speed of the turbocharger without increasing the emission levels. The increase in speed translates to an increased pressure ratio and mass flow rate of air. Additionally, the booster system was sustained by a small amount of fuel and air, which was removed from the compressor discharge piping. The cost for the amount of fuel required to fire the burner was small in comparison to the increase in compressor power. Since this compressor power is needed to deliver high air flow rates, the booster system could be used as a necessary component to keep engines compliant with the latest emissions standards. This paper provides test results that show how the system can be used to increase engines operating range and mitigate ambient effects.
Subjects: Uncategorized
Development of an Equation to Predict Flow Through Reciprocating Compressors
Manny Angulo, ACTT div. of CECO
For years, the industry has strived to predict the horsepower consumed by a reciprocating compressor using various equations. These equations have been very accurate for the chosen application. In the meantime, the industry for the most part continues to utilize the theoretical flow equation to predict the flow through the compressors. This paper will begin with the theoretical flow equation and derive a flow equation that can be used with currently collected compressor horsepower data.
Subjects: Uncategorized
Kirby Chapman, Ali Keshavarz & Diana Grauer, Kansas State University NGML
The development of a turbocharged engine system has allowed natural gas transmission companies to increase the air flow to the engine. This increased air flow has been strategically used to decrease pollutant emissions, such as NOX, to meet current emission regulations. In the future, regulations will be tightened, forcing transmission companies to look past turbochargers for compliance. The solution to further decreasing emissions lies not in further retrofit, but focusing on the physics of the current system. The physics of the manifold impedes equal distribution of air from the turbocharger to each cylinder. Imbalance in air flow creates a discontinuity in trapped equivalence ratio from cylinder to cylinder. Trapped equivalence ratio is directly proportional to NOX production and a function of the fuel flow rate, air flow rate, and, in a two-stroke cycle engine, the scavenging efficiency. Only when these three characteristics are balanced cylinder to cylinder will the combustion and the NOX production in each cylinder be equal. The engine NOX production will be disproportionately high if even one cylinder operates less lean relative to the other cylinders. This paper reports on an investigation into the transient, compressible flow physics that impact the trapped equivalence ratio. A comprehensive, variable geometry, multi-cylinder Turbocharger-Reciprocating Engine Computer Simulation (T-RECS) has been developed to illustrate the effect of airflow imbalance on an engine. A new model, the Charge Air Integrated Manifold Engine Numerical Simulation (CAIMENS), is a manifold flow model coupled with the T-RECS engine processor that uses an integrated set of fundamental principles to determine the crank angle-resolved pressure, temperature, burned and unburned mass fractions, and gas exchange rates for the cylinder. CAIMENS has the ability to show the transient impact of one cylinder firing on each successive cylinder. The pulsation model also describes the impact of manifold pressure drop on in-cylinder peak pressure and the pressure wave introduced to the intake manifold by uncovering the intake ports. CAIMENS will provide the information necessary to quantify the impact of airflow imbalance, and allow for the visualization of the engine system before and after airflow correction. The model showed that not only does the manifold pressure drop have a significant impact on the in-cylinder peak pressure, but it also has an impact on the pressure wave introduced to the intake manifold as the ports are opened. Also, each cylinder has a considerable impact on the airflow into each successive cylinder.
Subjects: Uncategorized
Dilution Effects of Gasses on Lubricating Oil in a Recip Compressor
Justin Yance, Ariel Corporation
Under pressure, carbon dioxide and natural gas have been suspected of lowering the viscosity of lubricating oil in a compressor. The data and research to support this theory is for the most part unavailable. There have been some investigations with gas dilution but only at pressures below about 350 psi and most of this research is proprietary to the companies that have conducted it. There is ongoing bearing research dealing with very high pressures on lubricating oil. These pressures are around 250,000 psi. Experiments were conducted from 0 to 3500 psi using industrial rust and oxidation inhibited (R&O) lubricating oil diluted with carbon dioxide gas and hydrocarbon gas. The findings of these experiments attempted to measure viscosity changes of the oil due to increased pressure.
Subjects: Uncategorized
Emission Reduction & Stability Improvement by Predictive Model Based Control of Legacy Gas Engines
Matthias Huschenbett, Hoerbiger/Daniel Alberer, Johannes Kepler University Linz/Greg Beshouri & Mark Richter, Advanced Engine Technologies Corp.
Modern advanced control methods have been identified as one key step to improve emission reduction as well as increased reliability and stability. Current control loops on legacy gas engines are acting mainly in independent cascaded PID loops. As a result, these separate controllers tend to hurt and cause an unstable behavior during transient changes. This can lead to significant emissions excursions requiring large compliance margins when operating at low emissions levels. An alternative approach is to replace the independent loops by a state-based controller which simultaneously sets all the loops. A Model Predictive Control (MPC) for two-stroke gas engines based on automotive engine systems has been developed as part of the ERLE program (Emission Reduction for Legacy Engines) initiated by the Pipeline Research Council International (PRCI). A dynamic gas engine model suitable for prediction of emission and engine behavior serves as the core of this control approach. The paper will describe the development of the process model for a TLA 6 using real time transient measurements and advanced simulation. This was in turn used to develop an explicit predictive control system which was then implemented in a fast prototyping system and tested on the TLA 6. The results of the initial field test together with a benefit assessment will be presented. Finally, the ongoing development of self tuning and adaptive strategies ensuring applicability to various legacy engines will be introduced.
Subjects: Uncategorized
Equivalence Ratio Modeling Techniques for Air Fuel Ratio Control
Dustin Malicke & Hans Mathews, Hoerbiger Engineering Services
This short course presents the equivalence ratio method of modeling for emissions and shows how this model can be used to create
and accurate air fuel ratio control scheme for lean burn pipeline engines. The course begins by teaching the basics of equivalence ratio modeling. It introduces a series of mathematical equations that are used in the non-dimensional equivalence ratio model. The modeling technique can be used to determine engine emissions performance under a wide variety of operating conditions will be covered in detail, so that the attendee will gain a solid understanding of the importance of mass air fuel ratio and its relationship to emissions. The authors will also covers secondary variables like scavenging and ignition timing. The second session of the course will focus on turning the emissions model around so that it can be deployed as an air fuel ratio control scheme. The details of equation development and implementation will be covered, as will the efforts required for commissioning. An example model will be used to show how the results from the equivalence ratio model and compare them to the results from some of the common approaches in the industry. At the conclusion of the short course, the attendee will not only understand the basics of equivalence ratio modeling, but they will also understand how this model can be used to develop a very robust air fuel ratio control scheme for lean burn pipeline engines.
Subjects: Uncategorized
Exhaust Gas Aftertreatment (Catalyst Systems)
Jon K. Tice, Enginuity
This short course will be an interactive tutorial workshop on the theory, design and application of exhaust aftertreatment systems for gas engines and will include coverage of NSCR (Non-Selective Catalytic Reactors) or “Three-Way Catalysts”, Oxidation Catalysts, SCR (Selective Catalytic Reactors) and the Air-Fuel Ratio Controls (AFRC) necessary to make them function. Extensive “real world” experience and treatment of what can go right, what can go wrong, and what to do about it will be presented. Specific examples will be used to illustrate the key points in the application of aftertreatment systems. Finally, there will be an overview discussion of emerging technology which is likely to be applied to gas engine aftertreatment systems
Subjects: Uncategorized
Gas Turbine Performance & Maintenance
Rainer Kurz, Solar Turbines Incorporated/Klaus Brun, Southwest Research Institute
Industrial gas turbines show performance characteristics that distinctly depend on ambient and operating conditions. They are not only influenced by site elevation, ambient temperature and relative humidity but also by the speed of the driven equipment, the fuel, and the load conditions. Proper application of gas turbines requires consideration of these factors. This short course explains these characteristics based on the performance of the engine compressor, the combustor and the turbine section and certain control strategies. It introduces fundamental concepts that help to understand the flow of energy between the components. Additionally, methods are introduced that allow the use of the data for trending and comparison purposes. Lastly, performance based maintenance strategies are discussed.
Subjects: Uncategorized
High Speed Permanent Magnet Motors
DirectDrive Systems
High Speed Permanent Magnet Motors
Subjects: Uncategorized
Hoerbiger Engineering Services 2007 GMC Tech Update
Hoerbiger
Hoerbiger Engineering Services 2007 GMC Tech Update
Subjects: Uncategorized
ACTT
IMPactt Training Update
Subjects: Uncategorized
The Importance of Proper Air Distribution in Two-Stroke Integral Engines
Tom Burgett, El Paso Pipeline Group/Jim McCoy, Hoerbiger Engineering Services Eric Dufur, ScavangeTech
At last year’s GMC, a paper was presented that described the conversion of a series of Cooper GMVA engines to turbocharged GMV engines while up-rating the horsepower of each unit in order to retire several older, inefficient units. This paper outlines the efforts and significant challenges in succesfully commissioning these engines. While commissioning the engines, and during subsequent engine operation , the engines exhibited a tendency to detonate even when operating at the prescribed air manifold pressure. A team of engineers and analysts was assembled to investigate the problem and find solutions. In parallel, physical investigations ensued through disassembly and visual inspection of engine components. The importance of adequate and equal air distribution to each cylinder, particularly in engines that will operate with a lean trapped air-to-fuel ratio to meet certain emissions limits, was one of the results that is described. On-engine investigation uncovered significant air imbalance, resulting in over-sensitive and unstable combustion. An engine flow simulation program was used to model flow in the engine, calculate the in-cylinder pressure and temperature of the unburned gases, and verified what was seen in the field testing and inspection work. Conventional methods of “cleaning the ports” were shown to be inadequate. Other issues, such as load changes on other engines when a different engine is being put online, or taken offline, were also addressed. The result has been the transformation of older engines, efficient in compressing gas, into up-rated, modernized, and now more reliable and fuel efficient engines, while producing lower emissions. This paper describes the process, problems and steps that were taken to identify and correct the problems.
Subjects: Uncategorized
The Influence of Clean Air Compliance on Engine Performance Parameters
Randy Raymer, El Paso Pipeline Group
This paper will cover the influences of changing the air-charge, fuel pressure (in the case of HPFI), and PCCs. It will demonstrate the effects on retarded LOPP & ignition timing, STDEV, PFP, exhaust temperatures, and CR (compression ratio). This paper will show real-time data, explain the calculations and cover what is needed to maintain operational flexibility as well as comply with EPA standards. Many companies have experienced difficulty in engine/compressor operation after these conversions. This paper will explain why and what to do to avoid issues in the future.
Subjects: Uncategorized
Joseph Fernandez, Ariel Corporation/Dwayne Hickman, ACI Services/Kelly Eberle, Beta Machinery
The effects of pressure pulsation attenuation devices on reciprocating compressors can dramatically affect unit performance, especially load, flow, pressure drops and safe operating map. An acoustical (pulsation) study is ordered after the unit has been sized and appropriate unloading hardware selected. Recommendations from the acoustical study typically include pulsation bottle designs, pipe layout designs, orifice plate sizes and locations, and in some cases, changes to unloading sequences. Many acoustical studies are based on detailed analysis of a select set of design operating points reviewed across the compressor’s specified speed range. The reality of compressor operations is that a compressor will operate at many points that are quite different from the selected design points. What really happens at these other operating points? Fortunately, today’s computers can model thousands of compressor operating points, including complete digital pulsation analysis, within hours. Thus, it is now possible to investigate a complete range of expected operating points prior to the unit actually being started. A complete acoustic review can identify areas in the operating map where high pulsations may still exist, to what extent flow and load are affected by the attenuation system, and how the effects of pulsations affect the safety of each load step. When end-users more fully understand how their compressor units will really perform, they are in a better position to optimize unit performance and increase station safety. Furthermore, if significant issues are identified early, then the packager, the pulsation analysis company, and the end-user can review alternative designs (hardware arrangements) or operating schemes.
Subjects: Uncategorized
Introduction to Rotary Screw Compressors
Hasu Gajjar, Hasu Gajjar & Associates, Inc.
Applications for compression of gases using interlocking helical rotors have advanced far beyond the refrigeration industry. Today, rotary screw compressors have a firm niche for natural gas compression. Used principally for high volume-low pressure applications, the rotary screw compressor is ideally suited for fuel gas boosting and wellhead compression, vapor recovery, landfill and digester gas recovery and other uses. Since the dynamics and physics of rotary screw compressors are vastly different from either separable or integral reciprocating compressors, it is important to have an understanding of the operation and efficiency of this type of compression. Important also is the correct matching of the compressor capacity and compressor screw Volume ratio-Vi to meet the specific needs of the pipeline operator with the engine driver to achieve the desired volumetric and adiabatic efficiency for each application with capacity control and Vi.
Subjects: Uncategorized
Norm Shade & Chad Brahler, ACI Services, Inc./Glen Chatfield & John Crandall, Optimum Power Technology
Effective control of the pressure pulsations generated by reciprocating compressors is necessary to prevent damaging shaking forces and stresses in system piping, vessels and mechanical equipment and structures, as well as to prevent detrimental time-variant suction and discharge pressures at the compressor cylinder flanges. Historically, pulsation control has been derived through the use of GMRC analog methodology and in recent years with high-end digital acoustic pulsation analysis programs. These system analyses are used to define the system elements required for control of pulsations upstream and downstream of the compressor cylinders. Pressure pulsations are typically controlled with a carefully designed system of primary and/or secondary volume bottles, often with complex internal choke tubes, baffles, and chambers, as well as various orifice plates installed at specific locations in the system piping. These devices accomplish pulsation control by adding resistance, or damping, to the system, and they virtually always result in some additional system pressure losses upstream and downstream of the compressor cylinders. While these pressure losses reduce the overall system
efficiency the trade-offs are reasonable and tolerable for most compressor applications. However, for common pipeline transmission applications having low pressure ratios (in the range of about 1.1 to 1.6) these system pressure losses can noticeably degrade system operating efficiency. As larger high-speed compressors have been increasingly applied to pipeline transmission applications, these effects have become more detrimental to performance, due to the higher frequency pulsations that must be dampened. In extreme cases in the field, traditional methods of pulsation control have been reported to add as much as 20 percent to the driver horsepower requirements for high-speed, low-ratio compressors. Finite amplitude wave technology has long been successfully applied to two-stroke engines to increase specific output and reduce exhaust emissions. Advanced computational technology exists for modeling and designing effective engine tuning systems for high-performance racing, recreational and industrial engine applications. Initial theoretical studies exploring the adaptation of this technology to higher pressure, mixed-gas composition, closed system compressor applications has shown dramatic potential, including control of pulsations to 1.0 percent peak-to-peak over a reasonable speed range with less than 0.1 percent overall system pressure drop. The results of further theoretical and experimental modeling are presented to evaluate the potential extension of this technology for the efficient control of reciprocating compressor pulsations.
Subjects: Uncategorized
Know What You Are Really Buying
Dwayne A. Hickman
Know What You Are Really Buying
Subjects: Uncategorized
Material Design for Valve Applications
Dr. Bernhard Spiegl, Hoerbiger Innovation & Technology/Thomas Kriechbaum, Hoerbiger Service, Inc./ Dr. Tim Bremner, Hoerbiger America Rings & Packings
Since the introduction of nonmetallic materials to the compressor market decades ago the valve suppliers constantly have tried to
increase the reliability and lifetime of valve sealing elements. Nevertheless, the improvement potential soon gets to the limitations of commercially available materials and production processes installed. All valve materials in use today were developed for general applications like automotive, consumer products and are not designed to match the needed properties in compressor. The load on valve sealing elements is quite unique due to the combination of dynamic impact loads, high temperature and gas exposure and the more or less static load by the differential pressures. The specific overall load combination requires purpose designed material. The basis to generate guidelines for new materials is the fundamental understanding of the loads occurring during operation and the micro mechanics involved during crack initiation and advancement. Different new purpose high performance materials with tailored structure, reinforcement and surface have already proven their outstanding properties in a high number of field test in critical installations all over the world in a three year field test.
Subjects: Uncategorized
Mobil Pegasus 1005 The Next Generation Gas Engine Oil
Mobil Industrial Lubricants
Mobil Pegasus 1005 The Next Generation Gas Engine Oil
Subjects: Uncategorized
One Compressor OEM May Not Have the Optimum Equipment Selection
Hap Schadler, DCP Midstream/Chad Brahler, ACI Services, Inc.
Over the years, the reciprocating compression industry has seen a reduction in the number of Original Equipment Manufacturers (OEM) and a streamline of products available as each OEM continues to design a standard product line. Although the OEM standard product line may provide an equipment solution for many projects, there are times when a solution offered by an OEM will not meet the requirements of the project or provide an optimum solution due to delivery constraints and/or standard product offering limitations. Whatever the reason, it is often desirable to utilize a mixture of OEM equipment offerings to meet the project requirements. One such example was a project recently completed by Duke Energy Field Services (DEFS), ACI Services, Inc., and WPI, Inc. for the DEFS LaGloria Gas Plant located in Falfurias, Texas. This paper reveals the practical details in applying existing Ariel JGC Class cylinders and OEM cylinders on an existing Superior WH compressor frame in a propane refrigeration application. It will provide in detail (1) the design approach required to identify the components required to mount the cylinders on the frame, (2) requirements to refurbish the existing equipment, (3) packaging related issues, and (4) operational and maintenance requirements.
Subjects: Uncategorized
Performance Through Leadership
Zahroof Mohamed
Performance Through Leadership
Subjects: Uncategorized
Chad Fletcher, Enginuity
Knowledge is a unique resource in that through its use more knowledge is generated. This basic truth results in the Knowledge Infrastructure being perhaps the one system within our grasp that will allow us to realize true perpetual motion. This paper will step beyond “Who Moved My Knowledge?” (presented at GMC2006) to explore the tools needed to be successful Knowledge Stewards and reverse the tide of knowledge loss within the industry. Specifically, the paper will define the architecture of the Knowledge Infrastructure that will make the Knowledge Vision a reality and create the Perpetual Motion Machine.
Subjects: Uncategorized
Portable Emission Testing Performance & Operating Procedures
Jim Stobbe, Windrock, Inc.
The objective of this course is to discuss the use of portable emission testing equipment and operating procedures for the performance of emission testing to determine the contents and levels of exhaust emissions and the mechanical condition of turbines and reciprocating engines. The course is designed for engineers and technicians who work with emissions monitoring and optimization. Course Summary:A review of equipment necessary prior to testing; Set-up procedures for portable emission analyzer (calibration helper, leak checks, sampling probe placement); Pre-test and post-test calibration check; Exhaust emissions measurement; Field data collection (fuel flow, RPM, load step); Emissions spreadsheet and reporting; Manual method (calibration gas concentration, pre-check and post-check data, emission test data, validation of span drift and calibration gas ranges).
Subjects: Uncategorized
Randy Anderson, ACTT div. of CECO
This short course will focus on power cylinder performance. The presentation will discuss and tie together various characteristics that affect power cylinder performance including: air fuel ratio, peak firing pressure, mean effective pressure, different rod configurations (master/articulated rod), detonation, misfire, and dead cylinders. The discussion will also present information from pressure-volume and pressure-time analysis correcting statistically for actual misfire and not defaulting to running compression.
Subjects: Uncategorized
PRCI’s Emissions Control for Legacy Engines Roadmap
Ted Bestor, El Paso Pipeline Group/Mike Whelan, PRCI
Compressor station air emissions compliance represents an ongoing and significant long-term financial and operational threat to gas pipelines. The “Emissions Control for Legacy Engines (ERLE)” program presents a realistic technology development roadmap developed by the PRCI Compressor & Pump Station Technical Planning Committee to create a cost-effective NOx control option to meet the very low NOx levels expected to be imposed on legacy reciprocating engines in the next 3 to 7 years. The ERLE program is entering its second year of effort, and initial results from the first year of research, as well as remaining tasks, will be discussed.
Subjects: Uncategorized
Reducing Emissions of a Large Bore Two-Stroke Engine Using a Natural Gas & Hydrogen Mixture
Kirby Chapman, Ali Keshavarz & Vince Van Norden, Kansas State University NGML
Engine researchers continually look for ways to reduce emissions such as NOx, CO, and CO2, in order to meet emissions regulations. NOx formation is primarily a function of temperature, with higher temperatures producing more NOx. Because of this, there is a desire to lower combustion temperatures while maintaining complete combustion. Blending hydrogen into an engine’s fuel can lower combustion temperatures and reduce emissions. This is due to how hydrogen acts as a fuel. It has a wide range of flammability in comparison with all other fuels, which allows for leaner engine operation and lower combustion temperatures. Hydrogen has a very high molecular diffusivity, which creates a more uniform mixture of fuel and air. Hydrogen also has very low ignition energy, which translates into easier combustion. For our research, a large bore, two stroke, single cylinder, natural gas fueled Ajax engine was used. The engine was brought up to the test point on pure natural gas and allowed to stabilize. Then, the blended fuel, a mixture of hydrogen and natural gas at different molar percentages, was introduced into the engine. Five percent hydrogen was tried first, and the percentage was increased by five percent until 30 percent was reached, as reported in many publications. Engine and emissions data were recorded while the engine operated on pure natural gas and each percentage of hydrogen. Physical observations were also noted, such as engine misfires. It was found that the addition of hydrogen did reduce emissions. The engine ran smoother and the speed increased while keeping the torque constant. This shows that the combustion was easier to initiate, as expected. There were no noticeable increase in misfires or engine knock as the hydrogen was added. Overall, it was found that hydrogen addition had a positive effect on the engine, and would be a good method of meeting emissions requirements. This paper reports the results of this study by quantifying emission reduction and engine combustion stability.
Subjects: Uncategorized
Revisiting Torsional Stiffness of Flexible Disc Couplings
Sam Steiner, Ameridrives Couplings
System torsional analysis is performed by packagers and OEMs to ensure the reliable operation of assembled systems such as engine compressor packages. This is especially critical when either the prime mover or the load is reciprocating machines with associated high levels of oscillating torque. Unexpectedly, high shaft stresses are likely to occur if the frequency of the oscillating torque coincides with a torsional critical speed. Failure to rigorously and accurately model this behavior can result in fatigue of torque-transmitting components with disastrous results. Flexible coupling characteristics are among the parameters used in system torsional analysis. Coupling manufacturers routinely supply weight, inertia, center of gravity, and torsional stiffness data for use by the system analyst. During the development of a new disc coupling product line, discrepancies were noted between historically and widely used coupling torsional stiffness data vs. the stiffness measured in laboratory tests. Subsequently, in-depth investigation was undertaken using FEA (Finite Element Analysis) and multiple lab tests on the proposed new coupling line as well as on competitor couplings in an attempt to more accurately model coupling torsional stiffness characteristics. Based on this research, new equations were derived which provide significant improvement in the accuracy of flexible disc coupling torsional stiffness calculations.
Subjects: Uncategorized
Ed Gemdjian, Kongsberg Maritime NJ/Larry Cornelius, Dow Chemical, Texas Operation
This paper presents information and test data, illustrating the importance of temperature as the fastest, most sensitive indicator of bearing condition in general and for the un-instrumented crank/connecting rod and crosshead bearings in particular. Parallels are drawn to the numerous studies recommendations and means of protection of stationary journal (main) bearings, most of all which are highly relevant for the non-stationary crankcase bearings of reciprocating machines, the crank and crosshead bearings. The subject of this paper covers a new technology, radar-wireless temperature sensors, instrumentation recently developed on the principle of a specialized radar excited surface acoustic wave (SAW) transducer, used in electronic highway toll collection systems (car tags), cell phone/appliance electromagnetic noise filters, etc. Therefore, the subject has nothing to do with the term “wireless” as widely used today – this is not telemetry nor wireless data collection/communication as currently known in general. Approved for hazardous areas, it consists of entirely passive components inside and around the machine. A brief introduction to the theory, applications and history of the new technology ispresented. The main section of the paper describes the applied technical solution for real-time temperature monitoring of non-stationary bearings. The principle of the underlying radar/SAW technology is presented followed by installation examples, drawings and photographs of permanent installations (in continuous operation since 2004 in North America, 2001 in Europe). The paper ends with conclusions from all the test data, numerous installations and “Users’ Views” feedback, including a case of prevented crankshaft damage.
Subjects: Uncategorized
Gas Machinery Research Council Siemens
Siemens Pipeline Compressor
Subjects: Uncategorized
Standardizing Compressor Station Automation
Jim Bowman & Mike Walden
Standardizing Compressor Station Automation
Subjects: Uncategorized
David Krenek Product Support Development Manager
Technology Update GMC 2007
Subjects: Uncategorized
Ed Flanagan, Windrock, Inc./James F. McCraw, BP America Inc./Bill Ashton, PCB Piezotronics
The use of pressure sensors on slow speed integral engines to measure internal dynamic combustion pressure is well proven and extensive. Such sensors have been used with portable analyzers in the Gas Industry on slow speed 2-stroke and 4-stroke engines for decades to balance combustion pressures and diagnose mechanical problems. Over the last 5 years, a new generation of piezoelectric pressure sensors has been developed for continuous use in large bore 2-stroke and 4-stroke integral engines. It is estimated that in excess of 2000 of these sensors are currently installed in the Gas Pipeline Industry. These sensors have proven extremely valuable as inputs to high pressure fuel injection systems designed to lower emission levels by allowing balancing of engine peak firing pressures, minimizing cycle-to-cycle deviations, misfires and detonation. Evidence also suggests that operators are realizing reduced costs in fuel and maintenance expenditures.The use of dynamic pressure sensors on high speed 4-stroke engines has been extremely limited. This is due to the lack of a convenient indicator port as is found on most large bore integral engines. Over the years, innovative users have attempted to use various pressure sensors for test purposes. The sensors have been installed in a variety of ways, such as modifying spark plugs with piezoelectric sensors. However, due to limitations in cost, ruggedness and maintenance considerations, the sensors have not been used extensively. The paper will present the results of the first large scale application of dynamic pressure sensor monitoring on high speed 4- stroke engines in the Gas Industry. We have now installed head bolt sensors on two CAT3608 engines with 8 more installations to followat BP’s San Juan Basin Operations. The paper will describe the innovative way the sensors are installed, special mounting considerations and calibration techniques. The monitoring system architecture and networking infrastructure will also be presented along with a discussion of how the combustion data can be used to enhance engine operations in the Gas Industry.
Subjects: Uncategorized
Thermo Chemical Recuperation (TCR) for Fuel Savings & Emissions Reduction at Compressor Engines
John Pratapas & Aleksandr Kozlov, Gas Technology Institute/Thomas Sine, Dresser-Rand
Approximately 60% of the total installed capacity of 12 million horsepower of pipeline compressor station engines used to transport anddistribute natural gas within New York State and the U.S. are reciprocating internal combustion engines. These engines are typically only 30-33% efficient, and natural gas consumers pay the fuel costs with other operating costs. With higher gas prices, there is a growing interest in and incentive to reduce fuel consumption associated with gas compression and transmission. Engine manufacturers and service companies are pursuing retrofit technologies to increase efficiency and reduce fuel consumption by offering improved turbocharging and improved combustion controls. However, 40% of the input fuel energy is lost as rejected heat through the engine exhaust. This paper will present findings from a project to evaluate a potential means of recovering and utilizing this waste heat to increase fuel efficiencies and reduce the fuel requirements on a prominent class of existing engines in New York State. New York State Energy Research and Development Authority (NYSERDA), Dresser-Rand and the Gas Technology Institute (GTI) are providing the funding for this project. The team of Dresser-Rand, GTI and National Fuel Gas recently collaborated on a project to evaluate the technical feasibility of using thermo chemical recuperation to reduce fuel consumption and emissions from pipeline compressor engines in New York State and the rest of the United States. Thermo chemical recuperation is a technology for converting waste heat energy typically rejected with the engine that can be recycled back to the engine to produce power. The reformed fuel resulting from TCR typically has as much as 25-30% hydrogen. Hydrogen enhanced combustion in reciprocating gas engines has been shown to be an effective means for extending the lean limit or increasing the engine tolerance for exhaust gas recirculation (EGR). Both lean combustion and the use of EGR are demonstrated techniques for reducing emissions of NOx from the engine. The paper will include results from modeling analyses of alternative schemes for recovering and utilizing waste heat for endothermic reforming for representative Dresser-Rand KVR engine design and operating conditions. One of the major tasks in the project is to operate the Dresser-Rand test engine with simulated reformed fuel from TCR. This unit is a two-cylinder four-stroke-cycle in-line engine that develops 750 brake horsepower at 350 rpm. It is used for testing and evaluation of engine systems including modifications. The paper will include performance and emissions test results comparing operation of the K4X engine on hydrogen/natural gas fuel blends both with and without pre-combustion chambers.
Subjects: Uncategorized
Torsional & Pulsation Design Audits
Mark A. Corbo & Stanley B. Malanoski, No Bull Engineering
The criticality of most gas processing machinery makes the performance of a rigorous design audit during the design phase almost
mandatory. The cost of such an audit, although not insignificant, is at least an order or magnitude lower than the cost of dealing with most field problems that the audit is designed to prevent. Although the contents of the audit can vary, depending on the machinery and application, two staples of a good design audit are a torsional vibration analysis and an acoustic/pulsation analysis. The aim of this short course is therefore, to educate users about these two highly critical subjects to the point where they understand the benefits accrued by performing these audits and have enough familiarity with them to intelligently review and critique the reports generated during this profess. Although the information presented will be applicable to all types of machinery, the preponderance of reciprocating compressors in the gas processing arena will lead to a sharpter focus on them. As would be expected, the short course is divided into two parts of approximately equal length – the first on torsional vibration and the second on pulsations.
Subjects: Uncategorized
Turbocharger Design & Performance Analysis
Damian Kuiper, Globe Turbocharger Specialties
Many aspects of turbocharger performance can be and are readily identified through performance testing. Although, when performance is less than satisfactory, test cell mapping only identifies secondary or tertiary troubles which demonstrate inconsistencies with expected performance. Such tasks as seeking out and eliminating efficiency losses or increasing operational surge margin are unrealistic expectations when basing your conclusions solely on inlet and discharge operating conditions. Identifying the root cause such as a mismatched impeller/diffuser or a poorly matched rotor/stator requires a complete aerodynamic analysis employed through a systematic investigation. Turbomachinery design and analysis software predicts the interactions of a working fluid with its geometrical surroundings and operational environment. Accurately predicting these interactions highly depends on understanding the energy loss models embedded within the design code. These loss models dictate how severely performance is diminished due to inherent or sometimes improper geometrical and operational constraints. Such energy losses include skin friction, excessive pressure recovery airfoil incidence, flow recirculation, and blade tip leakage to name a few. Working with aerodynamicists, Globe Turbocharger has fully integrated multiple centrifugal compressor and axial turbine performance codes into its design procedure. This procedure outlines a system of embedded relationships between component geometry, efficiency, performance margin, and on-engine operation. Combining detailed aerodynamic analysis with a systematic design methodology provides the turbomachinery designer and turbocharger end user a system wide perspective of how and why the turbocharger will perform under all operating conditions.
Subjects: Uncategorized
Uncertainty Considerations for Reciprocating Compressor Performance Testing
Robert J. McKee, Southwest Research Institute
Performance testing of reciprocating compressors has become important in the past few years as companies find it necessary to verify the efficiency of compressors and to identify the sources of horsepower loss. Different methods for performance testing such as methods based on Pressure-Volume measurements and methods based on suction and discharge enthalpy are being used to evaluate the performance of reciprocating compressors. Some operators favor one method over the other but very little analytic or quantified results have been collected to evaluate the different performance testing methods. An estimate of the uncertainty of a performance test result is one way to quantify the expected accuracy of a test method and to identify how useful a test method may be. When the performance of centrifugal compressors is measured, redundant transducers, a lot of care related to the stability of operations the period of data recording, the sampling of gas streams, and the measurement of atmospheric conditions are used to ensure accurate results are obtained. In addition, complete uncertainty calculations are conducted when a centrifugal compressor performance test is reported. However, when reciprocating compressor tests are conducted a minimum of transducer are used, gas flows and compositions are assumed, and many other details have normally simplified. The uncertainty analysis developed in this paper highlight the need for additional transducers, the careful accounting of gas properties and atmospheric conditions, and control of other operational factors. This paper presents an estimate of the uncertainty of reciprocating compressor performance tests under a number of different conditions by both the Pressure-Volume card method and the suction and discharge pressure and temperature enthalpy rise method. Examples of the uncertainty results will demonstrate the need for redundant measurements, for stable operating conditions, for better averaging techniques, and for accounting for atmospheric conditions and other influential variables. The potential results of the PV Card method compared to the enthalpy rise method by both a simplified and a proper more compete procedure will be compared. This paper should be of value for all who measure or consider measuring the performance of reciprocating compressors.
Subjects: Uncategorized
Lars Kahlman, SKF Industrial Division/Bill Bonis, SKF USA/Rod Mosher & Dean P. McInnes, Syncrude Canada Ltd.
A retrofit with new rolling bearing technology has resulted in a life increase in the excess of eight times for an oil-flooded screw compressor installation working under severe sour gas (40-50%) conditions. This work shows the possibilities to use oil-flooded screw compressors with rolling bearings as a highly reliable solution for demanding process gas applications within refineries, gas plants and gas well gathering. The various steps in the implementation of the new bearing system, practical experiences and the effects from the running of them will be given. In addition, the material design features of the bearings will be explained and the effects towards in the past encountered problems under severe process gas conditions will be discussed.
Subjects: Uncategorized
Variable Speed Planetary Gears for High Power Requirements
Christoph Meyenberg, Voith Turbo Inc.
Electric driven centrifugal compressor units are well established in the US pipeline system. Synchronous electric motor drives and variable speed planetary gears have been in use in the pipeline industry and today pipelines are going to be installed using turbo-compression for the first choice. New planned large scale pipelines reflect the growing demand of natural gas in the American economy in order to use clean fuel. Further new emission regulations make the use of gas turbines less efficient and expensive. High reliability, up-to-date efficiency, practically no emissions and low capital investment recommend electric driven compressor stations. The market of today requires unspared equipment with a power requirement of over 40,000 HP per station. This paper describes the latest developments in this power range, component design and starting and operation characteristics of the variable speed planetary gear. The operating range (torque vs. speed) is shown based on examples and its limits are explained. The extension of the product range towards higher power rating is not the only design aspect. Also, accessibility and maintainability issues have been considered to improve the operators’ satisfaction and reduce costly investments in infrastructure of compressor stations, for instance cranage capacity. Some recent examples of different oil and gas applications in the US are presented.
Subjects: Uncategorized
Waukesha ATGL Engine Controls Upgrade
Enginuity
Waukesha ATGL Engine Controls Upgrade
Subjects: Uncategorized
