scholarly journals Coal/Biomass Fuels and the Gas Turbine: Utilization of Solid Fuels and Their Derivatives

1996 ◽  
Author(s):  
Mario DeCorso ◽  
Richard Newby ◽  
Don Anson ◽  
Richard Wenglarz ◽  
Ian Wright
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Solid Fuels ◽  
Biomass Fuels ◽  
Design And Development ◽  
Refined Oil ◽  
Contaminant Level ◽  
Solid Form

This paper discusses key design and development issues in utilizing coal and other solid fuels in gas turbines. These fuels may be burned in raw form or processed to produce liquids or gases in more or less refined forms. The use of such fuels in gas turbines requires resolution of technology issues which are of little or no consequence for conventional natural gas and refined oil fuels. For coal, these issues are primarily related to the solid form in which coal is naturally found and its high ash and contaminant levels. Biomass presents another set of issues similar to those of coal. Among the key areas discussed are effects of ash and contaminant level on deposition, corrosion, and erosion of turbine hot parts, with particular emphasis on deposition effects.

Predicting Flameholding for Hydrogen and Natural Gas Flames at Gas Turbine Premixer Conditions

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Elliot Sullivan-Lewis ◽  
Vincent McDonell
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Experimental Studies ◽  
Temperature Variations ◽  
Auto Ignition ◽  
Chamber Temperature ◽  
Transient Events ◽  
Significant Effort

Lean-premixed gas turbines are now common devices for low emissions stationary power generation. By creating a homogeneous mixture of fuel and air upstream of the combustion chamber, temperature variations are reduced within the combustor, which reduces emissions of nitrogen oxides. However, by premixing fuel and air, a potentially flammable mixture is established in a part of the engine not designed to contain a flame. If the flame propagates upstream from the combustor (flashback), significant engine damage can result. While significant effort has been put into developing flashback resistant combustors, these combustors are only capable of preventing flashback during steady operation of the engine. Transient events (e.g., auto-ignition within the premixer and pressure spikes during ignition) can trigger flashback that cannot be prevented with even the best combustor design. In these cases, preventing engine damage requires designing premixers that will not allow a flame to be sustained. Experimental studies were conducted to determine under what conditions premixed flames of hydrogen and natural gas can be anchored in a simulated gas turbine premixer. Tests have been conducted at pressures up to 9 atm, temperatures up to 750 K, and freestream velocities between 20 and 100 m/s. Flames were anchored in the wakes of features typical of premixer passageways, including cylinders, steps, and airfoils. The results of this study have been used to develop an engineering tool that predicts under what conditions a flame will anchor, and can be used for development of flame anchoring resistant gas turbine premixers.

scholarly journals Natural Gas

2011 ◽  
Vol 133 (04) ◽  
pp. 52-52
Author(s):  
Rainer Kurz
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Oil And Gas ◽  
Electrical Power ◽  
Offshore Platforms ◽  
Electric Motors ◽  
Turbine Generator ◽  
Associated Gas ◽  
Generator Sets

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.

Optimizing Maintenance for Multi-Unit Industrial Gas Turbine Installations

2010 ◽  
Author(s):  
Markus Bohlin ◽  
Mathias Wa¨rja
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Preventive Maintenance ◽  
Gas Turbines ◽  
Economic Effects ◽  
Negative Effects ◽  
Component Level ◽  
Maintenance Schedule ◽  
Natural Gas Pipelines ◽  
Oil Platforms

High levels of availability and reliability are essential in many industries where production is subject to high costs due to downtime. Examples where gas turbines are used include the mechanical drive in natural gas pipelines and power generation on oil platforms, where it is common to use redundant gas turbines to mitigate the effects of service outage. In this paper, component-level maintenance of parallel multi-unit systems is considered, allowing production at a reduced level when some of the units are not operational. Units are themselves assumed to be composed out of components in a serial configuration; maintenance of one component implies shutdown of the unit. Parallel installations allow maintenance to be performed on one or a few gas turbines without taking down the entire installation. This allows maintenance to be optimized even further than in a serial system. However, the maintenance optimization process is made more complicated, since there now exist both positive and negative grouping effects. The positive grouping effects come from shared setup activities and costs, and the negative effects come from resource limitations, in this case the limited number of gas turbines which can be maintained at the same time. In the approach presented in this paper, each component has its individual preventive maintenance schedule, which is updated at inspections, changes in production and when indicated using remote condition monitoring. A minimal repair model for noncritical routine inspections and service tasks is assumed, which does not affect component state. In addition, previously developed procedures for estimating and measuring residual component lifetime for individual components during operation are used. The procedures are based on a Retirement For Cause (RFC) approach where components are not replaced until a potential failure has been detected. To maximize revenues for an operator, the available information is evaluated using software where scenario analysis and optimization is performed. To show the possible economic effects, gas turbine operation data is used together with maintenance and operator requirements as input for optimization of a production line consisting of a natural-gas compressor station having three SGT-600 gas turbines. Savings can be substantial compared to a traditional preventive maintenance plan.

Correlation of Landfill and Digester Gas Composition With Gas Turbine Pollutant Emissions

2006 ◽  
Author(s):  
V. G. McDonell ◽  
M. W. Effinger ◽  
J. L. Mauzey
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Wastewater Treatment Plants ◽  
Quantitative Relationship ◽  
Pollutant Emissions ◽  
Systematic Effect ◽  
Gas Composition ◽  
Emission Regulations ◽  
Carbon Dioxide Co2

The deployment of small gas turbines at landfills and wastewater treatment plants is attractive due to the availability of waste fuel gases generated at these sites and the need for onsite power and/or heat. The fuel gases produced by these applications typically contain 35 to 75% of the heating value of natural gas and contain methane (CH4) diluted primarily with carbon dioxide (CO2) and sometimes nitrogen (N2). Demonstrations of 30 to 250 kW gas turbines operating on these waste fuels are underway, but little detailed information on the systematic effect of the gas composition on performance is available. Growth in the use of small gas turbines for these applications will likely require that they meet increasingly stringent emission regulations, creating a need to better understand and to further optimize emissions performance for these gases. The current study characterizes a modified commercial natural gas fired 60 kW gas turbine operated on simluated gases of specified composition and establishes a quantitative relationship between fuel composition, engine load, and emissions performance. The results can be used to determine the expected impact of gas composition on emissions performance.

Efficiency Analysis of Gas Turbine Combined-Cycle Fed with Synthetic Natural Gas (SNG) and Mixture of Syngas and SNG

2015 ◽  
Vol 656-657 ◽  
pp. 113-118
Author(s):  
Hsiu Mei Chiu ◽  
Po Chuang Chen ◽  
Yau Pin Chyou ◽  
Ting Wang
Keyword(s):  
Natural Gas ◽  
Simulation Model ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combined Cycle ◽  
System Level ◽  
Minimum Requirement ◽  
Synthetic Natural Gas ◽  
System Level Simulation

The effect of synthetic natural gas (SNG) and mixture of syngas and SNG fed to Natural Gas Combined-Cycle (NGCC) plants is presented in this study via a system-level simulation model. The commercial chemical process simulator, Pro/II®V8.1.1, was used in the study to build the analysis model. The NGCC plant consists of gas turbine (GT), heat recovery steam generator (HRSG) and steam turbine (ST). The study envisages two analyses as the basic and feasibility cases. The former is the benchmark case which is verified by the reference data with the GE 7FB gas turbine. According to vendor’s specification, the typical net plant efficiency of GE 7FB NGCC with two gas turbines to one steam turbine is 57.5% (LHV), and the efficiency is the benchmark in the simulation model built in the study. The latter introduces a feasibility study with actual parameters in Taiwan. The SNG-fed GE 7FB based combined-cycle is evaluated, and the mixture of SNG and syngas is also evaluated to compare the difference of overall performance between the two cases. The maximum ratio of syngas to SNG is 0.14 due to the constraint for keeping the composition of methane at a value of 80 mol%, to meet the minimum requirement of NG in Taiwan. The results show that the efficiency in either case of SNG or mixture of SNG and syngas is slightly lower than the counterpart in the benchmark one. Because the price of natural gas is much higher than that of coal, it results in higher idle capacity of NGCC. The advantage of adopting SNG in Taiwan is that it could increase the capacity factor of combined-cycles in Taiwan. The study shows a possible way to use coal and reduce the CO2emission, since coal provides nearly half of the electricity generation in Taiwan in recent years.

Sequential Combustion in Gas Turbines: The Key Technology for Burning High Hydrogen Contents With Low Emissions

2019 ◽  
Author(s):  
Mirko R. Bothien ◽  
Andrea Ciani ◽  
John P. Wood ◽  
Gerhard Fruechtel
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Tuning Parameter ◽  
High Hydrogen ◽  
Stable Combustion ◽  
Second Stage ◽  
In Series ◽  
Exit Temperature

Abstract Excess energy generation from renewables can be conveniently stored as hydrogen for later use as a gas turbine fuel. Also, the strategy to sequestrate CO2 from natural gas will require gas turbines to run with hydrogen-based fuels. In such scenarios, high temperature low emission combustion of hydrogen is a key requirement for the future gas turbine market. Ansaldo Energia’s gas turbines featuring sequential combustion have an intrinsic advantage when it comes to fuel flexibility and in particular hydrogen-based fuels. The sequential combustion system is composed of two complementary combustion stages in series: one premix stage followed by an auto-ignited second stage overcoming the limits of traditional premix combustion systems through a highly effective extra tuning parameter, i.e. the temperature between the first and the second stage. The standard Constant Pressure Sequential Combustion (CPSC) system as applied in the GT36 engine is tested, at high pressure, demonstrating that a modified operation concept allows stable combustion with no changes in combustor hardware for the whole range of natural gas and hydrogen blends. It is shown that in the range from 0% to 70% (vol.) hydrogen, stable combustion is achieved at full nominal exit temperature, i.e. without any derating and thus clearly outperforming other available conventional premixed combustors. Operation between 70% and 100% is possible as well and only requires a mild reduction of the combustor exit temperature. By proving the transferability of the single-can high pressure results to the engine, this paper demonstrates the practicality of operating the Ansaldo Energia GT36 H-Class gas turbine on fuels containing unprecedented concentrations of hydrogen while maintaining excellent performance and low emissions both in terms of NOx and CO2.

Reactor Network Modeling of Stability and Emissions of Hydrogen and Natural Gas Blends for a Piloted Gas Turbine Combustor

2020 ◽  
Author(s):  
Candy Hernandez ◽  
Vincent McDonell
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Chemical Reactor ◽  
Experimental Results ◽  
Fuel Composition ◽  
Gas Turbine Combustor ◽  
Flammability Limits ◽  
Lean Premixed ◽  
Carbon Molecules

Abstract Lean-premixed (LPM) gas turbines have been developed for stationary power generation in efforts to reduce emissions due to strict air quality standards. Lean-premixed operation is beneficial as it reduces combustor temperatures, thus decreasing NOx formation and unburned hydrocarbons. However, tradeoffs occur between system performance and turbine emissions. Efforts to minimize tradeoffs between stability and emissions include the addition of hydrogen to natural gas, a common fuel used in stationary gas turbines. The addition of hydrogen is promising for both increasing combustor stability and further reducing emissions because of its wide flammability limits allowing for lower temperature operation, and lack of carbon molecules. Other efforts to increase gas turbine stability include the usage of a non-lean pilot flame to assist in stabilizing the main flame. By varying fuel composition for both the main and piloted flows of a gas turbine combustor, the effect of hydrogen addition on performance and emissions can be systematically evaluated. In the present work, computational fluid dynamics (CFD) and chemical reactor networks (CRN) are created to evaluate stability (LBO) and emissions of a gas turbine combustor by utilizing fuel and flow rate conditions from former hydrogen and natural gas experimental results. With CFD and CRN analysis, the optimization of parameters between fuel composition and main/pilot flow splits can provide feedback for minimizing pollutants while increasing stability limits. The results from both the gas turbine model and former experimental results can guide future gas turbine operation and design.

Enhanced Gas Turbine Combustor Performance Using H2-Enriched Natural Gas

1999 ◽  
Author(s):  
Jeffrey N. Phillips ◽  
Richard J. Roby
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Flame Speed ◽  
Gas Turbine Combustor ◽  
Flammability Limits ◽  
Combustion Performance ◽  
Exhaust Heat ◽  
Efficient Combustion

A screening level study has been carried out to examine the potential of using H2-enriched natural gas to improve the combustion performance of gas turbines. H2 has wider flammability limits and a higher flame speed than methane. Many previous studies have shown that when H2 is added to fuel, more efficient combustion and lower emissions will result. However, to date no commercial attempt has been made to improve the combustion performance of a natural gas-fired gas turbine by supplementing the fuel with H2. Four potential options for supplementing natural gas with H2 have been analyzed. Three of these options use the exhaust heat of the gas turbine either directly or indirectly to partially reform methane. The fourth option uses liquid H2 supplied from an industrial gas producer.

DME as a Potential Alternative Fuel for Gas Turbines: A Numerical Approach to Combustion and Oxidation Kinetics

2011 ◽  
Author(s):  
Pierre A. Glaude ◽  
Rene´ Fournet ◽  
Roda Bounaceur ◽  
Michel Molie`re
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Heat Input ◽  
Ignition Delay ◽  
Gas Turbines ◽  
Ignition Temperature ◽  
Alternative Fuels ◽  
Ignition Delay Times ◽  
Auto Ignition ◽  
Delay Times

Many investigations are currently carried out in order to reduce CO2 emissions in power generation. Among alternative fuels to natural gas and gasoil in gas turbine applications, dimethyl ether (DME; formula: CH3-O-CH3) represents a possible candidate in the next years. This chemical compound can be produced from natural gas or coal/biomass gasification. DME is a good substitute for gasoil in diesel engine. Its Lower Heating Value is close to that of ethanol but it offers some advantages compared to alcohols in terms of stability and miscibility with hydrocarbons. While numerous studies have been devoted to the combustion of DME in diesel engines, results are scarce as far as boilers and gas turbines are concerned. Some safety aspects must be addressed before feeding a combustion device with DME because of its low flash point (as low as −83°C), its low auto-ignition temperature and large domain of explosivity in air. As far as emissions are concerned, the existing literature shows that in non premixed flames, DME produces less NOx than ethane taken as parent molecular structure, based on an equivalent heat input to the burner. During a field test performed in a gas turbine, a change-over from methane to DME led to a higher fuel nozzle temperature but to a lower exhaust gas temperature. NOx emissions decreased over the whole range of heat input studied but a dramatic increase of CO emissions was observed. This work aims to study the combustion behavior of DME in gas turbine conditions with the help of a detailed kinetic modeling. Several important combustion parameters, such as the auto-ignition temperature (AIT), ignition delay times, laminar burning velocities of premixed flames, adiabatic flame temperatures, and the formation of pollutants like CO and NOx have been investigated. These data have been compared with those calculated in the case of methane combustion. The model was built starting from a well validated mechanism taken from the literature and already used to predict the behavior of other alternative fuels. In flame conditions, DME forms formaldehyde as the major intermediate, the consumption of which leads in few steps to CO then CO2. The lower amount of CH2 radicals in comparison with methane flames seems to decrease the possibility of prompt-NO formation. This paper covers the low temperature oxidation chemistry of DME which is necessary to properly predict ignition temperatures and auto-ignition delay times that are important parameters for safety.

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