Design and Maintenance Issues of Being Able to Repair Marine Gas Turbines Without Removal From the Ship

Author(s):  
Bruce D. Thompson ◽  
John J. Hartranft ◽  
Dan Groghan

Abstract When the concept of aircraft derivative marine gas turbines were originally proposed, one of the selling points was the engine was going to be easy to remove and replace thereby minimizing the operational impact on the ship. Anticipated Mean Time Between Removal (MTBR) of these engines was expected to be approximately 3000 hours, due mostly to turbine corrosion damage. This drove the design and construction of elaborate removal routes into the engine intakes; the expected time to remove and replace the engine was expected to be less than five days. However, when the first USN gas turbine destroyers started operating, it was discovered that turbine corrosion damage was not the problem that drove engine maintenance. The issues that drove engine maintenance were the accessories, the compressor, combustors and engine vibration. Turbine corrosion was discovered to be a longer term affect. This was primarily due to the turbine blade and vane coatings used and intake air filtration. This paper discusses how engine design, tooling development, maintenance procedure development and engine design improvements all contributed to extending the MTBR of USN propulsion and electrical power generation gas turbines on the DD 963, CG 47, DDG 51 and FFG 7 classes to greater than 20,000 hours. The ability to remove the gas turbine rapidly or in most cases repair the engine in-place has given the USN great maintenance flexibility, been very cost effective and not impacted operational readiness.

Author(s):  
Gunnar Lagerstro¨m ◽  
Max Xie

Rekuperator Svenska AB owned by VOLVO Technology Transfer Corporation and Avesta Polarit, has successfully developed a completely laser welded recuperator for micro-gas turbine applications. Tests have shown that the thermal performance is very competitive. The recuperator was installed in a 100 kW(e) micro-gas turbine power plant for combined electricity and heat generation by a customer. The recuperator is a primary surface counter flow heat exchanger with cross corrugated duct configuration. The primary heat transfer surface plate patterns are stamped and a pair of the plates are laser welded to form an air cell. The air cells are then stacked and laser welded together to form the recuperator core which is tied between two end beams. Manifolds for air inlet and outlet as well as piping system are welded to the core. Through varying the number of air cells the recuperator core can easily be adapted for micro-gas turbine applications with different output rates of electrical power. The key manufacturing technologies are stamping of the air cell plates and laser welding of the air cells. These processes can be fully automated for mass production at low costs.


Author(s):  
Ian Timbrell ◽  
Steve Mason ◽  
Alan Green ◽  
Neil McCallum

Following the design shift in Naval ship architecture from conventional mechanical through hybrid to Integrated Electric Propulsion (IEP), the starting philosophy of prime movers needs to be rationalised so as to interact and augment the propulsion configuration and electrical distribution whilst remaining cost effective. To fulfil this requirement the UK Ministry of Defence contracted Ultra Electronics (PMES) to work in partnership to develop and demonstrate a gas turbine Electric Start and Generation System (ESGS). The undertaken programme is to demonstrate full control over the gas turbine starting system and associated maintenance features together with generating sufficient electrical power that can be used to supply all the gas turbine alternator auxiliaries. This paper will give an overview of such requirements together with the design of the basic system and the challenges to ‘navalise’ such a product and install it on a marine gas turbine. The paper will continue by reviewing data obtained from factory acceptance testing and on-engine testing with the Marine Trent MT-30. It is hoped to further compare and analyse these results with future planned testing scheduled in late 2005. Conclusions will be drawn from the initial results, the design of the proposed ESGS system and comparisons with existing in-service gas turbine start systems.


Author(s):  
Steve Ingistov ◽  
Michael Milos ◽  
Rakesh K. Bhargava

A suitable inlet air filter system is required for a gas turbine, depending on installation site and its environmental conditions, to minimize contaminants entering the compressor section in order to maintain gas turbine performance. This paper describes evolution of inlet air filter systems utilized at the 420 MW Watson Cogeneration Plant consisting of four GE 7EA gas turbines since commissioning of the plant in November 1987. Changes to the inlet air filtration system became necessary due to system limitations, a desire to reduce operational and maintenance costs, and enhance overall plant performance. Based on approximately 2 years of operational data with the latest filtration system combined with other operational experiences of more than 25 years, it is shown that implementation of the high efficiency particulate air filter system provides reduced number of crank washes, gas turbine performance improvement and significant economic benefits compared to the traditional synthetic media type filters. Reasons for improved gas turbine performance and associated economic benefits, observed via actual operational data, with use of the latest filter system are discussed in this paper.


2011 ◽  
Vol 133 (05) ◽  
pp. 30-33 ◽  
Author(s):  
Lee S. Langston

This article explores the increasing use of natural gas in different turbine industries and in turn creating an efficient electrical system. All indications are that the aviation market will be good for gas turbine production as airlines and the military replace old equipment and expanding economies such as China and India increase their air travel. Gas turbines now account for some 22% of the electricity produced in the United States and 46% of the electricity generated in the United Kingdom. In spite of this market share, electrical power gas turbines have kept a much lower profile than competing technologies, such as coal-fired thermal plants and nuclear power. Gas turbines are also the primary device behind the modern combined power plant, about the most fuel-efficient technology we have. Mitsubishi Heavy Industries is developing a new J series gas turbine for the combined cycle power plant market that could achieve thermal efficiencies of 61%. The researchers believe that if wind turbines and gas turbines team up, they can create a cleaner, more efficient electrical power system.


2016 ◽  
Vol 138 (06) ◽  
pp. 38-43
Author(s):  
Lee S. Langston

This article discusses various fields where gas turbines can play a vital role. Building engines for commercial jetliners is the largest market segment for the gas turbine industry; however, it is far from being the only one. One 2015 military gas turbine program of note was the announcement of an U.S. Air Force competition for an innovative design of a small turbine engine, suitable for a medium-size drone aircraft. The electrical power gas turbine market experienced a sharp boom and bust from 2000 to 2002 because of the deregulation of many electric utilities. Since then, however, the electric power gas turbine market has shown a steady increase, right up to present times. Coal-fired plants now supply less than 5 percent of the electrical load, having been largely replaced by new natural gas-fired gas turbine power plants. Working in tandem with renewable energy power facilities, the new fleet of gas turbines is expected to provide reliable, on-demand electrical power at a reasonable cost.


2011 ◽  
Vol 133 (04) ◽  
pp. 52-52
Author(s):  
Rainer Kurz

This article discusses the importance of gas turbines, centrifugal compressors and pumps, and other turbomachines in processes that bring natural gas to the end users. To be useful, the natural gas coming from a large number of small wells has to be gathered. This process requires compression of the gas in several stages, before it is processed in a gas plant, where contaminants and heavier hydrocarbons are stripped from the gas. From the gas plant, the gas is recompressed and fed into a pipeline. In all these compression processes, centrifugal gas compressors driven by industrial gas turbines or electric motors play an important role. Turbomachines are used in a variety of applications for the production of oil and associated gas. For example, gas turbine generator sets often provide electrical power for offshore platforms or remote oil and gas fields. Offshore platforms have a large electrical demand, often requiring multiple large gas turbine generator sets. Similarly, centrifugal gas compressors, driven by gas turbines or by electric motors are the benchmark products to pump gas through pipelines, anywhere in the world.


Author(s):  
Todd Parker

Natural gas transmission systems have many sources of fugitive methane emissions that have been difficult to eliminate. This paper discusses an option for dealing with one such source for operations using turbo-compressor units fitted with dry gas seals. Dry seals rely on a small leakage of process gas to maintain the differential pressure of the process against the atmosphere. The seal leakage ultimately results in waste gas that is emitted to the atmosphere through the primary vent. A simple, cost effective, emission disposal mechanism for this application is to vent the seal gas into the gas turbine’s air intake. Explosion hazards are not created by the resultant ultra-lean fuel/air mixture, and once this mixture reaches the combustion chamber, where sufficient fuel is added to create a flammable mixture, significant oxidation of the seal vent gas is realized. Background of the relevant processes is discussed as well as a review of field test data. Similar applications have been reported [1] for the more generalized purpose of Volatile Organic Compound (VOC) destruction using specialized gas turbine combustor designs. As described herein, existing production gas turbine combustors are quite effective at fugitive methane destruction without specialized combustor designs.


1984 ◽  
Vol 106 (4) ◽  
pp. 935-939
Author(s):  
H. A. Kidd

The continued use of gas turbines in industrial applications and increased customer desires for trend analysis has led gas turbine suppliers to develop sophisticated, reliable, cost-effective vibration monitoring systems. This paper discusses the application of case vibration monitoring systems and the design criteria for each component. Engine installation, transducer mounting brackets, types of transducers, interconnecting cables and connectors, charge amplifiers, and signal conditioning and monitoring are considered. Examples are given of the benefits experienced with the final system in several of Dresser Clark’s engine development programs, by manufacturing and production testing, and by Dresser’s field service staff.


Author(s):  
Ralph E. Harris ◽  
Harold R. Simmons ◽  
Anthony J. Smalley ◽  
Richard M. Baldwin ◽  
George Quentin

This paper illustrates how software and hardware for telecommunications and data acquisition enable cost-effective monitoring of peaking gas turbines using personal computers. It describes the design and evaluation of a system which transmits data from each start-up and shutdown over 1,500 miles to a monitoring computer. It presents system structure, interfaces, data content, and management. The system captures transient sequences of acceleration, synchronization, loading, thermal stabilization, steady operation, shutdown and cooldown; it yields coherent sets of speed, load, temperature, journal eccentricity, vibration amplitude, and phase at intervals appropriately spaced in time and speed. The data may be used to characterize and identify operational problems.


Author(s):  
J. E. Donald Gauthier

This paper describes the results of modelling the performance of several indirectly fired gas turbine (IFGT) power generation system configurations based on four gas turbine class sizes, namely 5 kW, 50 kW, 5 MW and 100 MW. These class sizes were selected to cover a wide range of installations in residential, commercial, industrial and large utility power generation installations. Because the IFGT configurations modelled consist of a gas turbine engine, one or two recuperators and a furnace; for comparison purpose this study also included simulations of simple cycle and recuperated gas turbine engines. Part-load, synchronous-speed simulations were carried out with generic compressor and turbine maps scaled for each engine design point conditions. The turbine inlet temperature (TIT) was varied from the design specification to a practical value for a metallic high-temperature heat exchanger in an IFGT system. As expected, the results showed that the reduced TIT can have dramatic impact on the power output and thermal efficiency when compared to that in conventional gas turbines. However, the simulations also indicated that several configurations can lead to higher performance, even with the reduced TIT. Although the focus of the study is on evaluation of thermodynamic performance, the implications of varying configurations on cost and durability are also discussed.


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