Dr. Michael J. Drosjack (Drosjack Consulting, LLC, The Woodlands, TX); James M. Sorokes and Harry F. Miller (Dresser-Rand, Olean, NY) Description:
| The machinery utilized in the oil and gas industry (Upstream, Midstream, and Downstream) is undergoing very significant changes. In past years, the use of new designs or prototype machinery was strongly discouraged. Changes were modest and taken slowly. However, rapidly escalating changes in operating environments and requirements are requiring users and manufacturers to pursue “step outs” or, as defined in this paper, Serial #1 machinery. These authors detail some of the design challenges being encountered by users and manufacturers. A number of specific design challenges that have been encountered in the centrifugal compressor arena are described. Considerable engineering and design details for these specific challenges are discussed. The goal of this discussion is to provide the readers with some level of understanding of both the challenges they are facing and the manner in which they may address them while managing the risk inherent in these designs. |
Tutorial T6: Simplified Modal Analysis for the Plant Machinery Engineer
| Wednesday, September 26, 2012 |
10:30 AM |
Level Three, Room 360A |
Instructors:
| José A. Vázquez (BRG Machinery Consulting, LLC, Wilmington, DE), C. Hunter Cloud (BRG Machinery Consulting, LLC, Charlottesville, VA), and Robert J. Eizember (DuPont Company, Wilmington, DE) |
Description:
| Experimental modal analysis and operating deflection shapes (ODS) are powerful tools in vibration analysis and machinery troubleshooting. However, the machinery plant engineer often doesn’t believe such techniques are available given a lack of advanced measurement equipment. This tutorial presents best practices with simplified experimental modal analysis and ODS techniques that can be used by a plant machinery engineer with the limited vibration analysis equipment usually available at a plant site. Minimum requirements and analyzer settings are discussed for a variety of commonly available measurement equipment. For different machinery problems, common measurement pitfalls and limitations are reviewed and, where appropriate, alternative methods are presented. During the presentation, demonstrations of modal testing measurements will be conducted using a portable generic data acquisition system. |
Tutorial T7: Gas Turbine Performance and Maintenance
Presented Twice
| Tuesday, September 25, 2012 |
2:00 PM |
Level Three, Room 360A |
| Wednesday, September 26, 2012 |
10:30 AM |
Level Three, Room 362A |
Instructors:
| Rainer Kurz (Solar Turbines Incorporated, San Diego, CA); Cyrus Meher-Homji (Bechtel Corporation, Houston, TX); Klaus Brun and Jeff Moore (Southwest Research Institute, San Antonio, TX) |
Description:
| This tutorial will focus on the performance and maintenance aspects that are critical to obtain reliable and efficient operation of gas turbines. Topics covered will be key performance characteristics of gas turbines and factors that impact performance degradation including inlet air systems, air filtration, and fuel quality. The focus is on practical information that will help operators understand the importance of these factors in day-to-day operation. Topics covered include the basics of gas turbine performance, compressor fouling, washing, fuel treatment, combustion, and condition monitoring. |
Tutorial T8: Babbitt Bearing Health Assessment
| Wednesday, September 26, 2012 |
10:30 AM |
Level Three, Room 360C |
Instructors:
| John K. Whalen (John Crane Bearings, Houston, TX), Thomas D. Hess, Jr. and John F. Craighton (DuPont Engineering, Wilmington, DE), Jim Allen (Nova Chemicals Corporation, Joffre, AB) |
Description:
| Within most plants there is often a desire to extend the time between outages. Several factors determine this but one to consider is the bearings’ ability to run for the extended time. This tutorial will address common bearing failure mechanisms, tools available to diagnose these problems, and ways to use that information to make decisions on continued operation. Evaluation consists of analysis of condition monitoring information coupled with rotor dynamic analysis and computerized bearing modeling. A case study will be presented that details the evaluation of a distressed bearing. Analysis allowed the user to determine they could slightly reduce running speed (to limit vibration to a certain level) and continue to run to the scheduled outage date. There will then be a discussion on bearing robustness and ways to design bearings for long life. A case study will be presented where an ethylene plant desired to extend the time between outages but the existing bearings prohibited that. The determination was made that upgrading the bearings to a more robust design would allow the extended time between outages. |
Tutorial T9: VSDS Motor Inverter Design Concept for Compressor Trains Avoiding Interharmonics in Operating Speed Range
| Wednesday, September 26, 2012 |
2:00 PM |
Level Three, Room 360A |
Instructors:
| Volker Hütten and Tim Krause (Siemens Energy Sector, Duisburg, Germany), Christian Beer (Siemens Energy Sector, Erlangen, Germany), Sven Demmig (Siemens Industry Sector, Nuremberg, Germany) |
Description:
| The mechanical integrity of torque transmitting elements of a VSDS driven train is strongly dependent on the in-depth understanding of the torsional oscillation excitation caused by the interharmonics generated in inverters. To ensure a reliable operation an elegant and pragmatic strategy to avoid interharmonic excitations within the operating speed range has been developed. |
Tutorial T10: Torsional Natural Frequencies: Measurement versus Prediction
| Tuesday, September 25, 2012 |
2:00 PM |
Level Three, Room 360C |
Instructors:
| Qingyu Wang and Brian C. Pettinato (Elliott Group, Jeannette, PA); Troy D. Feese (Engineering Dynamics Inc., San Antonio, TX) |
Description:
| Torsional system design is commonly based on the API Standards, which require the torsional natural frequencies (TNFs) to have at least 10% separation margin (SM) from any excitation frequency or justification by stress analysis. The validity of the predicted TNF and any stress analysis is dependent on the accuracy of the model. This paper provides an uncertainty study of more than ten (10) torsional systems. Major sources of uncertainty in torsional modeling are identified. The effect of variation in mass-elastic data is examined, and a comparison between measured and predicted TNFs for numerous cases is presented. Results indicate that prediction error can exceed the 5% mark discussed in previous literature. |
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