Salt in the Marine Environment and the Creation of a Standard Input for Gas Turbine Air Intake Filtration Systems

2004 ◽  
Author(s):  
Peter T. McGuigan
Keyword(s):  
Boundary Layer ◽  
Pressure Drop ◽  
Gas Turbine ◽  
Marine Environment ◽  
Gas Turbines ◽  
Marine Boundary Layer ◽  
Primary Concern ◽  
Air Filtration ◽  
Filtration System ◽  
Recent Developments

Contaminants are ever-present in the air. Contaminated air entering a Gas Turbine will damage internal components and bring about a reduction in overall efficiency. The amount of contaminant entering a Gas Turbine, therefore, needs to be minimised. This paper describes recent developments in the understanding of one such contaminant, salt. It describes how salt is produced, how it varies climatically and how it varies from location to location and is presented here in the context of the author’s particular field of competence — air filtration system design. Salt ingestion by a Gas Turbine intake can cause corrosion and, given time, can accumulate on the compressor blades and reduce the aerodynamic efficiency. The removal of salt in the air is therefore of primary concern to all those involved in the design and operation of Gas Turbines. Salt removal systems are manufactured in various guises. The concept, however, remains the same — salt capture upstream of the Compressor stage. The drawback to this method of salt removal is that it results in a decrease in air pressure entering the Compressor and will consequently bring about a decrease in the overall system performance. As the requirement to remove more and more salt contaminant increases, the pressure drop across the method of filtration required to achieve this, increases. The responsibility of the Filtration Engineer is therefore to fully understand the requirements of the Gas Turbine, to understand the balance between pressure drop, salt removal and salt size and, consequently, to design an appropriate filtration system — one fit for purpose. Gas Turbines in the marine environment are generally found at heights less than 50m above sea level. It is this environment (the Marine Boundary Layer) which historically has been difficult to fully quantify. Herein lies the problem for those involved — if the environment is not fully understood how can the proper exploitation of the technologies be achieved? Recent developments, however, have led to a better understanding of salt in the Marine Boundary Layer. This paper describes these recent developments.

Evolution of Gas Turbine Intake Air Filtration in a 420 MW Cogeneration Plant

2014 ◽  
Author(s):  
Steve Ingistov ◽  
Michael Milos ◽  
Rakesh K. Bhargava
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Economic Benefits ◽  
Cogeneration Plant ◽  
Air Filtration ◽  
Air Filter ◽  
Filter System ◽  
Turbine Performance ◽  
Filtration System ◽  
Operational Data

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.

2-Stage Air Filtration for Gas Turbine Naval Applications

2019 ◽  
Author(s):  
Gianluca de Arcangelis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Turbine Blades ◽  
Water Repellency ◽  
Air Filtration ◽  
Compressor Blades ◽  
Reduced Pressure ◽  
Filtration System ◽  
Offshore Oil

Abstract Traditional air filtration systems for Gas Turbine Naval applications consist of 3 stages: 1st vane separator + pocket filter + 2nd vane separator. The 2nd vane separator is required to drain out droplets formed by the traditional pocket filter during its coalescing function. Further to technological advancements in the water repellency of filter media, as well as leak-free techniques, it is now possible to implement a pocket filter that avoids leaching water droplets downstream. This enables the elimination of the 3rd stage vane separator in the air filtration system. The result is a suitable 2-stage air filtration system. The elimination of the 3rd stage vane separator provides the obvious following advantages: • Reduced pressure drop • Reduced weight • Reduced foot-print • Reduced cost Latest technological advancements in water repellency and high efficiency melt-blown media also allow the attainment of higher performance such as: • Increased efficiency against water droplet and salt in wet state • Increased efficiency against dry salt and dust This results in higher cleanliness of the Gas Turbines with benefits in terms of compressor fouling, compressor blades corrosion and turbine blades hot erosion. Higher performance also results in simplified maintenance as technicians need only focus on the replacement of the elements as opposed to the cleaning and overhauling of the intake duct. The paper goes through the engineering challenges of evolving from a 3-stage to 2-stage filtration system. The paper provides data from testing at independent laboratories with results that back the claims. Furthermore, reference is made to Offshore Oil & Gas installations and testing that have proven successful with independently measured data.

Strategy for Selecting Optimised Technologies for Gas Turbine Air Inlet Filtration Systems

2011 ◽  
Author(s):  
Stephen D. Hiner
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Quality ◽  
Air Filtration ◽  
Air Inlet ◽  
Filtration System ◽  
The World ◽  
Maintenance Requirements ◽  
Specific Challenge ◽  
Over Time

With continuous advances in gas turbine technology, wider breadth of fuel quality burnt and ever growing expectations of; longer life, higher efficiency and reduced maintenance requirements, the filtration of the air entering the gas turbine (GT) has never been more important to meeting its operational requirements. Gas turbines are used throughout the world in an ever increasing diversity of application and environment. This presents a number of challenges to the air filtration system, that require unique solutions for each subset of environment specific challenge, gas turbine platform technology and fuel quality being burnt. This paper discusses the importance of air filtration to a modern GT and how this has changed over time and it’s shifting operational requirements. It explores the challenges facing the air filtration system presented by the different; environments, GT technologies and fuel quality. The paper details what approaches and filtration technologies are currently used to address these challenges, with strengths and weaknesses explained as appropriate, to finally present a strategy for specifying an optimized filtration system to meet the challenges of the modern GT.

Experimental Evaluation of Compressor Blade Fouling

2016 ◽  
Author(s):  
Rainer Kurz ◽  
Grant Musgrove ◽  
Klaus Brun
Keyword(s):  
Boundary Layer ◽  
Gas Turbines ◽  
Blade Surface ◽  
Air Filtration ◽  
Ambient Conditions ◽  
Compressor Blades ◽  
Performance Deterioration ◽  
Quantitative Results ◽  
The Impact ◽  
Dust Retention

Fouling of compressor blades is an important mechanism leading to performance deterioration in gas turbines over time. Experimental and simulation data are available for the impact of specified amounts of fouling on performance, as well as the amount of foulants entering the engine for defined air filtration systems and ambient conditions. This study provides experimental data on the amount of foulants in the air that actually stick to a blade surface for different conditions of the blade surface. Quantitative results both indicate the amount of dust as well as the distribution of dust on the airfoil, for a dry airfoil, as well as airfoils that were wet from ingested water, as well as different types of oil. The retention patterns are correlated with the boundary layer shear stress. The tests show the higher dust retention from wet surfaces compared to dry surfaces. They also provide information about the behavior of the particles after they impact on the blade surface, showing that for a certain amount of wet film thickness, the shear forces actually wash the dust downstream, and off the airfoil. Further, the effect of particle agglomeration of particles to form larger clusters was observed, which would explain the disproportional impact of very small particles on boundary layer losses.

Combustion Technology for Low-Emissions Gas-Turbines: Some Recent Modeling Results

1996 ◽  
Vol 118 (3) ◽  
pp. 201-208 ◽  
Author(s):  
S. M. Correa ◽  
I. Z. Hu ◽  
A. K. Tolpadi
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Spectroscopic Data ◽  
Physical Models ◽  
Gas Turbine Combustor ◽  
Finite Rate ◽  
Recent Developments ◽  
Combustion Technology ◽  
Computationally Intensive ◽  
Transport Method

Computer modeling of low-emissions gas-turbine combustors requires inclusion of finite-rate chemistry and its intractions with turbulence. The purpose of this review is to outline some recent developments in and applications of the physical models of combusting flows. The models reviewed included the sophisticated and computationally intensive velocity-composition pdf transport method, with applications shown for both a laboratory flame and for a practical gas-turbine combustor, as well as a new and computationally fast PSR-microstructure-based method, with applications shown for both premixed and nonpremixed flames. Calculations are compared with laserbased spectroscopic data where available. The review concentrates on natural-gas-fueled machines, and liquid-fueled machines operating at high power, such that spray vaporization effects can be neglected. Radiation and heat transfer is also outside the scope of this review.

Boundary Layer Flashback Limits of Hydrogen-Methane-Air Flames in a Generic Swirl Burner at Gas Turbine Relevant Conditions

2020 ◽  
Author(s):  
Dominik Ebi ◽  
Peter Jansohn
Keyword(s):  
Boundary Layer ◽  
Gas Turbine ◽  
Wall Temperature ◽  
Gas Turbines ◽  
High Speed ◽  
Cooling System ◽  
Atmospheric Conditions ◽  
Preheat Temperature ◽  
Swirl Burner ◽  
Wide Range

Abstract Operating stationary gas turbines on hydrogen-rich fuels offers a pathway to significantly reduce greenhouse gas emissions in the power generation sector. A key challenge in the design of lean-premixed burners, which are flexible in terms of the amount of hydrogen in the fuel across a wide range and still adhere to the required emissions levels, is to prevent flame flashback. However, systematic investigations on flashback at gas turbine relevant conditions to support combustor development are sparse. The current work addresses the need for an improved understanding with an experimental study on boundary layer flashback in a generic swirl burner up to 7.5 bar and 300° C preheat temperature. Methane-hydrogen-air flames with 50 to 85% hydrogen by volume were investigated. High-speed imaging was applied to reveal the flame propagation pathway during flashback events. Flashback limits are reported in terms of the equivalence ratio for a given pressure, preheat temperature, bulk flow velocity and hydrogen content. The wall temperature of the center body along which the flame propagated during flashback events has been controlled by an oil heating/cooling system. This way, the effect any of the control parameters, e.g. pressure, had on the flashback limit was de-coupled from the otherwise inherently associated change in heat load on the wall and thus change in wall temperature. The results show that the preheat temperature has a weaker effect on the flashback propensity than expected. Increasing the pressure from atmospheric conditions to 2.5 bar strongly increases the flashback risk, but hardly affects the flashback limit beyond 2.5 bar.

Gas Turbine Fouling Offshore: Correction Methodology Compressor Efficiency

2017 ◽  
Author(s):  
Stian Madsen ◽  
Lars E. Bakken
Keyword(s):  
Gas Turbine ◽  
Peak Load ◽  
Operational Experience ◽  
Air Filtration ◽  
Ambient Conditions ◽  
Key Factors ◽  
Turbine Performance ◽  
Main Challenge ◽  
Filtration System ◽  
Compressor Efficiency

Gas turbine performance has been analyzed for a fleet of GE LM2500 engines at two Statoil offshore fields in the North Sea. Both generator drive engines and compressor driver engines have been analyzed, covering both the LM2500 base and plus configurations, as well as the SAC and DLE combustor configurations. Several of the compressor drive engines are running at peak load (T5.4 control), and the production rate is thus limited to the available power from these engines. The majority of the engines discussed run continuously without redundancy, implying that gas turbine uptime is critical for the field’s production and economy. Previous studies and operational experience have emphasized that the two key factors to minimize compressor fouling are the optimum designs of the inlet air filtration system and the water wash system. An optimized inlet air filtration system, in combination with daily online water wash (at high water-to-air ratio), are the key factors to achieve successful operation at longer intervals between offline washes and higher average engine performance. Operational experience has documented that the main gas turbine recoverable deterioration is linked to the compressor section. The main performance parameter when monitoring compressor fouling is the gas turbine compressor efficiency. Previous studies have indicated that inlet depression (air mass flow at compressor inlet) is a better parameter when monitoring compressor fouling, whereas instrumentation for inlet depression is very seldom implemented on offshore gas turbine applications. The main challenge when analyzing compressor efficiency (uncorrected) is the large variation in efficiency during the periods between offline washes, mainly due to operation at various engine loads and ambient conditions. Understanding the gas turbine performance deterioration is of vital importance. Trending of the deviation from the engine baseline facilitates load-independent monitoring of the gas turbine’s condition. Instrument resolution and repeatability are key factors for attaining reliable results in the performance analysis. A correction methodology for compressor efficiency has been developed, which improves the long term trend data for effective diagnostics of compressor degradation. Avenues for further research and development are proposed in order to further increase the understanding of the deterioration mechanisms, as well as gas turbine performance and response.

Boundary Layer Flashback in Premixed Hydrogen–Air Flames With Acoustic Excitation

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Vera Hoferichter ◽  
Thomas Sattelmayer
Keyword(s):  
Boundary Layer ◽  
Flow Velocity ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Excitation Amplitude ◽  
Bulk Flow ◽  
Acoustic Excitation ◽  
Worst Case ◽  
Thermoacoustic Instabilities ◽  
Flame Flashback

Lean premixed combustion is prevailing in gas turbines to minimize nitrogen oxide emissions. However, this technology bears the risk of flame flashback and thermoacoustic instabilities. Thermoacoustic instabilities induce velocity oscillations at the burner exit which, in turn, can trigger flame flashback. This article presents an experimental study at ambient conditions on the effect of longitudinal acoustic excitation on flashback in the boundary layer of a channel burner. The acoustic excitation simulates the effect of thermoacoustic instabilities. Flashback limits are determined for different excitation frequencies characterizing intermediate frequency dynamics in typical gas turbine combustors (100–350 Hz). The excitation amplitude is varied from 0% to 36% of the burner bulk flow velocity. For increasing excitation amplitude, the risk of flame flashback increases. This effect is strongest at low frequencies. For increasing excitation frequency, the influence of the velocity oscillations decreases as the flame has less time to follow the changes in bulk flow velocity. Two different flashback regimes can be distinguished based on excitation amplitude. For low excitation amplitudes, flashback conditions are reached if the minimum flow velocity in the excitation cycle falls below the flashback limit of unexcited unconfined flames. For higher excitation amplitudes, where the flame starts to periodically enter the burner duct, flashback is initiated if the maximum flow velocity in the excitation cycle is lower than the flashback limit of confined flames. Consequently, flashback limits of confined flames should also be considered in the design of gas turbine burners as a worst case scenario.

Experimental Investigations of Pressure Drop in the Combustion Chamber of Gas Turbine

1989 ◽  
Author(s):  
Marek Dzida ◽  
Krzysztof Kosowski
Keyword(s):  
Pressure Drop ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Relative Pressure ◽  
Wide Range ◽  
Few Data

In bibliography we can find many methods of determining pressure drop in the combustion chambers of gas turbines, but there is only very few data of experimental results. This article presents the experimental investigations of pressure drop in the combustion chamber over a wide range of part-load performances (from minimal power up to take-off power). Our research was carried out on an aircraft gas turbine of small output. The experimental results have proved that relative pressure drop changes with respect to fuel flow over the whole range of operating conditions. The results were then compared with theoretical methods.

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

2019 ◽  
Author(s):  
Bruce D. Thompson ◽  
John J. Hartranft ◽  
Dan Groghan
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Electrical Power ◽  
Corrosion Damage ◽  
Cost Effective ◽  
Air Filtration ◽  
Expected Time ◽  
Engine Vibration ◽  
Engine Design ◽  
Engine Maintenance

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.

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