7EA Users Group Annual Conference – 2021
The 7EA Users Group will be held August 23-27, 2021 at the Marriott St. Louis Grand in St. Louis, MO.
We’re as committed to your machine output as you are. MD&A offers gas turbine services ranging from Combustion, Hot Gas Path and Major Inspections, as well as, Compressor & Turbine Rotor Repairs to Plant Performance Testing and Analysis. Whether it’s an inspection or a repair, MD&A will design the solution you need to address your specific fleet issues and keep you running efficiently.
Tour MD&A’s state-of-the-art 250,000 square foot Turbine-Generator Repair Facility!
Monday, August 23, 2021, OR Friday, August 27, 2021 – Tour Schedule:
- 8:00 AM – 8:15 AM: Load buses
- 8:15 AM – 8:35 AM: Buses in transit to MD&A repair facility
- 8:35 AM – 8:45 AM: Arrive, get safety glasses
- 8:45 AM – 11:15 AM: Tours – 6 stops, discussion, Q&A
- 11:15 AM – 11:45 AM: Load buses and return to the hotel
- RSVP required within conference registration, limit 90 each day
- Conference badges required to load bus
- Closed-toe shoes required; Safety glasses provided at the shop
7EA users can attend 7F Monday, August 23, 2021, sessions from 2-6 pm:
2-2:45 pm Rotor Life Assessment
15 min break
3:10pm Design Enhancements: 7FA 1-2 Spacer Cracking Presentation
3:40-4:10 pm 7F Gas Turbine Alignment
15 min break
4:35 pm 7F Enhanced Component Solutions and Repairs
5:15 Gas Turbine Thermodynamic Analysis & Performance Testing
Title: Rotor Life Assessment
Length: 45 mins
Speaker(s): Rich Rucigay and Fred Willett
Rotors in gas turbines produced in the 1990s and early 21st century are approaching the number of starts and hours defined by the OEM as the design service life (aka End-of-Life). However, the defined rotor service life is based on a probabilistic assessment and is conservative for a majority of the gas turbines in the fleet. The recommended service life is based on many factors including duty cycle, ambient environment, maintenance practices, material properties, etc. Furthermore, rotor end-of-life is governed by but a few of the rotor components. The remaining rotor components may have additional maintenance intervals of useful life remaining. A comprehensive rotor inspection and end-of-life assessment can help turbine owners/operators determine what course of action to take to ensure that their rotors continue to operate safely and reliably.
Information needed for a rotor end-of-life assessment can be broken down into two categories: general design information and user-specific information. In the former category are such items as material properties, accurate dimensional characterization, and an understanding of failure modes. The latter category includes operating history, site conditions, location and extent of any defects (as determined by a complete non-destructive inspection), and the expected profile of the future operation. A sound engineering analysis starts with the general information to build an accurate rotor model, then applies the user-specific information to execute the analysis.
MD&A offers gas turbine rotor components that have been engineered for full compatibility with OEM rotors, as well as equivalent performance and durability. MD&A combines our servicing, repair, and parts expertise with Mitsubishi Power®’s experience in rotor inspection and remaining life analysis to provide an OEM-caliber end-of-life assessment program for gas turbine rotors. This presentation shares the details of MD&A’s gas turbine rotor life extension solutions.
Title: Design Enhancements: 7FA 1-2 Spacer Cracking
Length: 30 mins
Speaker(s): Fred Willett
7FA turbine rotors that entered service in the late 1990s and early 21st century are approaching the number of starts and hours defined by the OEM as the design life. Increased cyclic operation and faster starts have combined to accelerate the rotor cyclic life consumption. A new concern among 7FA operators is the durability of the 1-2 spacer.
The potential for spacer cracking is greatest at the underside of the spacer rim. A finite element model and turbine operating data are used to determine the mechanical and thermal loading of the spacer during transient and steady-state operation. Results of the finite element analysis show a likely crack initiation site. Finally, the presentation will describe MD&A’s improved spacer design.
Title: 7F Gas Turbine Alignment
Length: ~30 mins
Speaker(s): Charles Monestere
This presentation reviews component alignment checks required for GE® 7F turbine bearing and casing alignments with common problems identified. Additionally, we will review the impact of casing distortion and bore positions relative to the machine centerline and the impact on Tip Clearances.
Title: 7F Component Life Extension
Length: 30 mins
Speaker(s): José M. Quiñones, P.E
Typical gas turbine components operate to the OEM recommended useful life. In order to determine if the components are candidates for a lifetime extension, we need to understand if the parent material has the properties needed to operate one more service interval. We also need to ensure that the repair that will be implemented can also operate for one more service interval. In the process of learning about the component’s condition we also get to understand their failure modes. Our repair center has repaired over 1,200 F-class sets of components. This presentation will cover the typical limiting factors of 7F gas turbine components and how they can be repaired. We will cover the steps used in implementing a lifetime extension and will show specific case studies.
Title: Gas Turbine Thermodynamic Analysis and Performance Testing
Length: ~30 mins
Speaker(s): Jim Miller
The presentation will discuss the importance of monitoring key parameters when conducting gas turbine performance testing. Gas turbine testing should include cycle isolation and thermal surveys to identify components that are contributing to performance losses. We will discuss some examples of problems identified during gas turbine testing and how they impacted performance.
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