Influence of Variations in the Natural Gas Properties on the Combustion Process in Terms of Emissions and Pulsations for a Heavy-Duty Gas Turbine

2003 ◽  
Author(s):  
Lars O. Nord ◽  
Helmer G. Andersen
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Mechanical Damage ◽  
Combustion Noise ◽  
Combustion Instabilities ◽  
Ambient Conditions ◽  
Process Data ◽  
Gas Properties

The natural gas supply can vary significantly on a day-to-day or even hour-to-hour basis for a power plant equipped with gas turbines. The influence of such variations could potentially have an adverse effect on the combustion process in terms of emissions and acoustic pulsations, even if the fuel properties are within the original equipment manufacturer (OEM) guidelines. Since the operation of a gas turbine typically requires steady emissions within the air permit as well as low pulsations to limit mechanical damage on the unit, fuel variations could significantly affect how the unit can be operated. To investigate this matter, data from an ALSTOM GT11N1 gas turbine was collected and studied during a 6-month period. The data acquired included on-line gas chromatograph readings, frequency-analyzed combustion instabilities, various process data, as well as ambient conditions. The collected data shows the magnitude of the changes in the emissions and combustion noise with changes in the fuel. The conclusion is that normal day-to-day variations in the natural gas properties do not have a significant effect on the emissions and combustion instabilities; however, larger sudden changes, as exemplified in the paper, could lead to considerable changes in the combustion behavior of the unit.

A Study of Parameters Affecting the Combustion Stability and Emissions Behavior of Alstom Heavy-Duty Gas Turbines

2004 ◽  
Author(s):  
Lars O. Nord ◽  
Helmer G. Andersen
Keyword(s):  
Gas Turbines ◽  
Combustion Instability ◽  
Nox Reduction ◽  
Fuel Properties ◽  
Combustion Noise ◽  
Combustion Stability ◽  
Combustion Instabilities ◽  
Heavy Duty ◽  
Ambient Conditions ◽  
Process Data

A number of factors can influence the combustion instability region and emission behavior of a heavy-duty gas turbine. Changes in the composition of the natural gas supplied have an impact that was studied in a prior investigation, which focused on parameters such as fuel temperature and composition. To further investigate the fuel sensitivity additional plants were included in this study. In addition to the fuel properties the distribution of the fuel inside the combustor was examined. To expand the fuel properties study, additional parameters were examined. Ambient conditions were paid special interest, specifically ambient temperature and humidity. Included in this study was also the effect on combustion of changes in compressor discharge pressure. With the growing interest in inlet chilling a pulsation/emission study was included to specifically look for NOx and combustion instability effects due to inlet chilling. Also, influences from special occurrences such as on-line compressor washing were examined. The turbines in this study utilize a silo-type combustor with either the DLN [Dry Low NOx] EV [EnVironmental] burners or with single diffusion burners using water or steam as NOx reduction medium. The rated power output of the gas turbines was in the range of 50–120 MW. The data acquired included frequency-analyzed combustion instabilities, various process data, as well as ambient conditions and fuel composition. The collected data shows the magnitude of the changes in the emissions and combustion noise with changes in the parameters studied. The conclusion is that some key parameters are very important for both the pulsations and the emissions, whereas others can be neglected. Some parameters affect the combustion instabilities only, without noticeable effect on emissions, and vice versa.

Effect of Hydrogen Content on the Gas Turbine Combustion Performance of Synthetic Natural Gas

2013 ◽  
Author(s):  
Min Chul Lee ◽  
Seik Park ◽  
Uisik Kim ◽  
Sungchul Kim ◽  
Jisu Yoon ◽  
...  
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Gas Turbine ◽  
Hydrogen Content ◽  
Gas Turbines ◽  
Combustion Instabilities ◽  
Synthetic Natural Gas ◽  
Natural Gases ◽  
Combustion Performance ◽  
Gas Turbine Combustion

This paper investigates the effect of hydrogen content on the gas turbine combustion performance of synthetic natural gases to determine whether they are adaptable to industrial gas turbines. Synthetic natural gases which are composed of methane, propane and varying amounts of hydrogen (0%, 1%, 3% and 5%), are tested in ambient pressure and high temperature conditions at the combustion test facility of a 60kWth industrial gas turbine. Combustion instabilities, flame structures, temperatures at nozzle, dump plane and turbine inlet, and emissions of NOx and CO are investigated for the power outputs from 35 to 60kWth. With increasing hydrogen content, combustion instabilities are slightly alleviated and the frequency of pressure fluctuation and heat release oscillation is increased. NOx and CO emissions are almost similar in trends and amounts for all tested fuels, and the undesirable phenomena from addition of hydrogen such as flashback, auto-ignition and overheating of fuel nozzle were not observed. Synthetic natural gas with less than 1% hydrogen showed no difference in gas turbine combustion characteristics, while synthetic natural gases containing hydrogen of over 3% showed a slight difference in combustion instability such as amplitude and frequency of pressure fluctuations and heat release oscillations. From these results, we conclude that the synthetic natural gas containing less than 1% hydrogen is adaptable without retrofitting any part of the combustor, and Korea coal-SNG Quality Standard Bureau is planning to establish the SNG quality standards, guaranteeing hydrogen content of up to 1%.

Combustion of Natural Gas, Hydrogen and Bio-Fuels at Ultra-Wet Conditions

2011 ◽  
Author(s):  
Sebastian Go¨ke ◽  
Steffen Terhaar ◽  
Sebastian Schimek ◽  
Katharina Go¨ckeler ◽  
Christian O. Paschereit
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Pure Hydrogen ◽  
Nox Emissions ◽  
Steam Content ◽  
Wide Range ◽  
Air Mixing ◽  
Flame Flashback

Humidified Gas Turbines promise a significant increase in efficiency compared to the dry gas turbine cycle. In single cycle applications, efficiencies up to 60% seem possible with humidified turbines. Additionally, the steam effectively inhibits the formation of NOx emissions and also allows for operating the gas turbine on hydrogen-rich fuels. The current study is conducted within the European Advanced Grant Research Project GREENEST. The premixed combustion at ultra wet conditions is investigated for natural gas, hydrogen, and mixtures of both fuels, covering lower heating values between 27 MJ/kg and 120 MJ/kg. In addition to the experiments, the combustion process is also examined numerically. The flow field and the fuel-air mixing of the burner were investigated in a water tunnel using Particle Image Velocimetry and Laser Induced Fluorescence. Gas-fired tests were conducted at atmospheric pressure, inlet temperatures between 200°C and 370°C, and degrees of humidity from 0% to 50%. Steam efficiently inhibits the formation of NOx emissions. For all tested fuels, both NOx and CO emissions of below 10 ppm were measured up to near-stoichiometric gas composition at wet conditions. Operation on pure hydrogen is possible up to very high degrees of humidity, but even a relatively low steam content prevents flame flashback. Increasing hydrogen content leads to a more compact flame, which is anchored closer to the burner outlet, while increasing steam content moves the flame downstream and increases the flame volume. In addition to the experiments, the combustion process was modeled using a reactor network. The predicted NOx and CO emission levels agree well with the experimental results over a wide range of temperatures, steam content, and fuel composition.

The Employment of Hydrogenerated Fuels From Natural Gas Reforming: Gas Turbine and Combustion Analysis

2004 ◽  
Vol 126 (3) ◽  
pp. 489-497 ◽  
Author(s):  
Fabio Bozza ◽  
Maria Cristina Cameretti ◽  
Raffaele Tuccillo
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Plant Performance ◽  
Nitric Oxides ◽  
Performance And Emission ◽  
Natural Gas Reforming

An integrated method for power plant analysis, including rotating component matching and CFD simulation of the combustion process, is applied to the study of gas turbines supplied with hydrogenated fuels originating from the natural gas reforming. The method proposed by the authors allows estimation of the power plant performance and emission in the gas turbine operating range. A comparison is then carried out between the plant behavior with conventional fuelling and with decarbonised fuel supply. Attention is also paid to the study of the combustion regimes with either natural gas or fuels with increasing hydrogen contents, in order to achieve a realistic insight of both the temperature distributions and the growth of nitric oxides throughout the combustion chamber.

The Employment of Hydrogenated Fuels From Natural Gas Reforming: Gas Turbine and Combustion Analysis

2002 ◽  
Author(s):  
Fabio Bozza ◽  
Maria Cristina Cameretti ◽  
Raffaele Tuccillo
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cfd Simulation ◽  
Combustion Process ◽  
Plant Performance ◽  
Nitric Oxides ◽  
Performance And Emission ◽  
Natural Gas Reforming

An integrated method for power plant analysis, including rotating component matching and CFD simulation of the combustion process, is applied to the study of gas turbines supplied with hydrogenated fuels originating from the natural gas reforming. The method proposed by the authors allows estimation of the power plant performance and emission in the gas turbine operating range. A comparison is then carried out between the plant behaviour with conventional fuelling and with decarbonised fuel supply. Attention is also paid to the study of the combustion regimes with either natural gas or fuels with increasing hydrogen contents, in order to achieve a realistic insight of both the temperature distributions and the growth of nitric oxides throughout the combustion chamber.

First Assessment of Biogas Co-Firing on the GE MS9001FA Gas Turbine Using CFD

2003 ◽  
Author(s):  
J. A. Lycklama a` Nijeholt ◽  
E. M. J. Komen ◽  
A. J. L. Verhage ◽  
M. C. van Beek
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Geometrical Model ◽  
Electricity Production ◽  
Power Station ◽  
Complete Combustion ◽  
Air Mixing ◽  
The Impact

Replacement of fossil fuel by biomass-derived fuel is currently under study in the Netherlands within the context of CO2 -neutral electricity production. In view of this, co-firing biogas in the natural-gas fired Eems gas turbine power plant is being considered. This would entail extension of the power station with a biomass gasification plant for the production of biogas. The main unit of the Electrabel Eemshaven Power Station consists of five GE MS9001FA-gas turbines. A target is to replace up to 13% of natural gas consumption by biogas. The objective of the current project was to determine the impact of co-firing on the flame behavior. Therefore various options for biogas co-firing using combinations of pilot and premix burners have been studied. Computational Fluid Dynamics (CFD) simulations of the combustion process using a geometrical model of the complete combustion chamber have been performed. The flow conditions at the premix burner outlets were determined with a separate, detailed CFD model of the burner, simulating the fuel-air mixing with the required high accuracy. Advanced combustion modeling with help of the detailed GRI 3.0-reaction mechanism was used, as well as simpler models for fast chemical kinetics. A method was devised for calibrating the applied combustion models. Various firing strategies involving the premix and pilot burners were analyzed. Safe ranges for biogas co-firing have been determined in this first feasibility study.

scholarly journals Comprehensive Thermodynamic Analysis of the Humphrey Cycle for Gas Turbines with Pressure Gain Combustion

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3521 ◽  
Author(s):  
Panagiotis Stathopoulos
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Process ◽  
Ideal Gas ◽  
Point Of View ◽  
Pressure Gain Combustion ◽  
Combustion Technology ◽  
Secondary Air ◽  
And Performance ◽  
The Impact

Conventional gas turbines are approaching their efficiency limits and performance gains are becoming increasingly difficult to achieve. Pressure Gain Combustion (PGC) has emerged as a very promising technology in this respect, due to the higher thermal efficiency of the respective ideal gas turbine thermodynamic cycles. Up to date, only very simplified models of open cycle gas turbines with pressure gain combustion have been considered. However, the integration of a fundamentally different combustion technology will be inherently connected with additional losses. Entropy generation in the combustion process, combustor inlet pressure loss (a central issue for pressure gain combustors), and the impact of PGC on the secondary air system (especially blade cooling) are all very important parameters that have been neglected. The current work uses the Humphrey cycle in an attempt to address all these issues in order to provide gas turbine component designers with benchmark efficiency values for individual components of gas turbines with PGC. The analysis concludes with some recommendations for the best strategy to integrate turbine expanders with PGC combustors. This is done from a purely thermodynamic point of view, again with the goal to deliver design benchmark values for a more realistic interpretation of the cycle.

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.

Prediction of Pressure Rise in a Gas Turbine Exhaust Duct Under Flameout Scenarios While Operating On Hydrogen and Natural Gas Blends

2021 ◽  
Author(s):  
Orlando Ugarte ◽  
Suresh Menon ◽  
Wayne Rattigan ◽  
Paul Winstanley ◽  
Priyank Saxena ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Combustion Model ◽  
Computational Domain ◽  
Cfd Model ◽  
Exhaust Duct ◽  
Gas Turbine Exhaust ◽  
Turbine Exhaust

Abstract In recent years, there is a growing interest in blending hydrogen with natural gas fuels to produce low carbon electricity. It is important to evaluate the safety of gas turbine packages under these conditions, such as late-light off and flameout scenarios. However, the assessment of the safety risks by performing experiments in full-scale exhaust ducts is a very expensive and, potentially, risky endeavor. Computational simulations using a high fidelity CFD model provide a cost-effective way of assessing the safety risk. In this study, a computational model is implemented to perform three dimensional, compressible and unsteady simulations of reacting flows in a gas turbine exhaust duct. Computational results were validated against data obtained at the simulated conditions in a representative geometry. Due to the enormous size of the geometry, special attention was given to the discretization of the computational domain and the combustion model. Results show that CFD model predicts main features of the pressure rise driven by the combustion process. The peak pressures obtained computationally and experimentally differed in 20%. This difference increased up to 45% by reducing the preheated inflow conditions. The effects of rig geometry and flow conditions on the accuracy of the CFD model are discussed.

scholarly journals Application of a three-step approach for prediction of combustion instabilities in industrial gas turbine burners

2017 ◽  
Vol 1 ◽  
pp. JCW78T
Author(s):  
Dmytro Iurashev ◽  
Giovanni Campa ◽  
Vyacheslav V. Anisimov ◽  
Ezio Cosatto ◽  
Luca Rofi ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Time Lag ◽  
High Amplitude ◽  
Combustion Regime ◽  
Industrial Test ◽  
Distributed Model ◽  
Combustion Instabilities ◽  
Acoustic Oscillations ◽  
Analytical Time

Abstract Recently, because of environmental regulations, gas turbine manufacturers are restricted to produce machines that work in the lean combustion regime. Gas turbines operating in this regime are prone to combustion-driven acoustic oscillations referred as combustion instabilities. These oscillations could have such high amplitude that they can damage gas turbine hardware. In this study, the three-step approach for combustion instabilities prediction is applied to an industrial test rig. As the first step, the flame transfer function (FTF) of the burner is obtained performing unsteady computational fluid dynamics (CFD) simulations. As the second step, the obtained FTF is approximated with an analytical time-lag-distributed model. The third step is the time-domain simulations using a network model. The obtained results are compared against the experimental data. The obtained results show a good agreement with the experimental ones and the developed approach is able to predict thermoacoustic instabilities in gas turbines combustion chambers.

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