Analysis of Water–Fuel Ratio Variation in a Gas Turbine With a Wet-Compressor System by Change in Fuel Composition

The wet compressor (WC) has become a reliable way to reduce gas emissions and increase gas turbine efficiency. However, fuel source diversification in the short and medium terms presents a challenge for gas turbine operators to know how the WC will respond to changes in fuel composition. For this study, we assessed the operational data of two thermal power generators, with outputs of 610 MW and 300 MW, in Colombia. The purpose was to determine the maximum amount of water that can be added into a gas turbine with a WC system, as well as how the NOx/CO emissions vary due to changes in fuel composition. The combustion properties of different gaseous hydrocarbon mixtures at wet conditions did not vary significantly from each other—except for the laminar burning velocity. It was found that the fuel/air equivalence ratio in the turbine reduced with lower CH4 content in the fuel. Less water can be added to the turbine with leaner combustion; the water/fuel ratio was decreased over the range of 1.4–0.4 for the studied case. The limit is mainly due to a reduction in flame temperature and major risk of lean blowout (LBO) or dynamic instabilities. A hybrid reaction mechanism was created from GRI-MECH 3.0 and NGIII to model hydrocarbons up to C5 with NOx formation. The model was validated with experimental results published previously in literature. Finally, the effect of atmospheric water in the premixed combustion was analyzed and explained.

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Experimental Study on High Pressure Combustion of Decomposed Ammonia: How Can Ammonia Be Best Used in a Gas Turbine?

10.1115/gt2021-60057 ◽

2021 ◽

Author(s):

Mario Ditaranto ◽

Inge Saanum ◽

Jenny Larfeldt

Keyword(s):

Experimental Study ◽

High Pressure ◽

Gas Turbine ◽

Gas Turbines ◽

Favourable Effect ◽

Small Scale ◽

Nox Formation ◽

Fuel Blends ◽

Combustion Properties ◽

Fuel Mixtures

Abstract Hydrogen, a carbon-free fuel, is a challenging gas to transport and store, but that can be solved by producing ammonia, a worldwide commonly distributed chemical. Ideally, ammonia should be used directly on site as a fuel, but it has many combustion shortcomings, with a very low reactivity and a high propensity to generate NOx. Alternatively, ammonia could be decomposed back to a mixture of hydrogen and nitrogen which has better combustion properties, but at the expense of an endothermal reaction. Between these two options, a trade off could be a partial decomposition where the end use fuel is a mixture of ammonia, hydrogen, and nitrogen. We present an experimental study aiming at finding optimal NH3-H2-N2 fuel blends to be used in gas turbines and provide manufacturers with guidelines for their use in retrofit and new combustion applications. The industrial burner considered in this study is a small-scale Siemens burner used in the SGT-750 gas turbine, tested in the SINTEF high pressure combustion facility. The overall behaviour of the burner in terms of stability and emissions is characterized as a function of fuel mixtures corresponding to partial and full decomposition of ammonia. It is found that when ammonia is present in the fuel, the NOx emissions although high can be limited if the primary flame zone is operated fuel rich. Increasing pressure has shown to have a strong and favourable effect on NOx formation. When ammonia is fully decomposed to 75% H2 and 25% N2, the opposite behaviour is observed. In conclusion, either low rate or full decomposition are found to be the better options.

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Experimental Investigation of Fuel Composition Effects on Syngas Combustion

Volume 3: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration ◽

10.1115/gt2015-42401 ◽

2015 ◽

Cited By ~ 2

Author(s):

Thijs Bouten ◽

Martin Beran ◽

Lars-Uno Axelsson

Keyword(s):

Experimental Investigation ◽

Heat Release ◽

Gas Turbine ◽

Alternative Fuels ◽

Oil And Gas ◽

Flame Temperature ◽

Fuel Composition ◽

Lean Blowout ◽

Track Record ◽

Syngas Combustion

The OPRA OP16 gas turbine is an all radial single-shaft gas turbine rated at 1.9 MW with a successful track record from oil and gas applications as well as industrial and commercial CHP applications. To meet the growing demand for alternative fuels, OPRA Turbines has developed a new tubular combustor for the OP16 gas turbine fleet. The combustor has been successfully tested on a wide variety of (ultra-) low-calorific gaseous fuels in an atmospheric combustion test rig. This paper presents an experimental investigation of syngas combustion in the low-calorific fuel combustor. The effect of the variation in fuel composition on the combustion characteristics has been investigated extensively. This includes the effect of variable heating values and variations in the ratio between hydrogen and carbon monoxide and between syngas and hydrocarbons. The effects of these variations on the combustor performance, emissions and lean blowout limits will be discussed and compared to the results obtained from the combustion of propane. Major differences in emissions have been found, mainly influenced by the flame temperature and presence of hydrogen in the fuel. Lean blowout of the combustor is largely determined by the presence of hydrogen, whereas other components are found to have less influence. Theoretical calculation, based on le Chatelier’s rule and a method based on heat release, of the lean blowout limit has been compared to the experiments. It was found that the heat release method predicts the flammability limit more accurately than le Chatelier’s rule. This is caused by the inaccuracy of the latter to handle fuels with a large amount of hydrogen.

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Effects of Diluent Gases on Combustion of Coal Gasification Gas: Comparison Between N2 and CO2 Dilutions

ASME/JSME 2011 8th Thermal Engineering Joint Conference ◽

10.1115/ajtec2011-44290 ◽

2011 ◽

Author(s):

Yukihide Nagano ◽

Kunihoro Kado ◽

Tomohiro Takeo ◽

Yukito Miki ◽

Toshiaki Kitagawa

Keyword(s):

Coal Gasification ◽

Burning Velocity ◽

Flame Temperature ◽

Co2 Concentration ◽

Generation System ◽

High Co2 ◽

Combustion Properties ◽

High Co2 Concentration ◽

Power Generation System ◽

Turbulent Burning Velocity

Combustion properties of coal gasification gas with CO2 dilution were investigated for a newly proposed IGCC power generation system with CO2 capture. In this system, the gasification gas was burned under high CO2 concentration atmosphere. In order to clarify the properties of the flames under such atmosphere, the laminar and turbulent burning velocities were investigated for outwardly propagating stoichiometric H2/O2/CO2 and H2/O2/N2 flames under the two conditions, 1: the same amount of diluent of CO2 or N2, 2: the constant flame temperature irrespective of diluents. Under the condition1 of the same amount of diluents, the unstretched laminar burning velocities, ul of CO2 diluted flames were smaller than those of N2 diluted flames. The ratios of the turbulent burning velocity at the flame radius 30mm, utn(30mm) to ul of the CO2 diluted flames were found to be larger than those of N2 diluted flames. Under the condition2 of the constant flame temperature, it was set to 1300, 1500, 1700, and 2135 degrees Celsius. At the flame temperatures except for 2135 degrees Celsius, ul of CO2 diluted flames were slightly smaller than those of N2 diluted flames. The ratios, utn(30mm) / ul of CO2 diluted flames were larger than those of N2 diluted flames. Increase in the turbulence Karlovitz number and decrease in the Markstein number by the CO2 dilution might cause the increase in utn(30mm) / ul of CO2 diluted flames in both conditions.

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Effects of Flame Temperature and Fuel Composition on Soot Formation in Gas Turbine Combustors

Combustion Science and Technology ◽

10.1080/00102208308923706 ◽

1983 ◽

Vol 35 (1-4) ◽

pp. 117-131 ◽

Cited By ~ 14

Author(s):

David W. Naegeli ◽

Lee G. Dodge ◽

Clifford A. Moses

Keyword(s):

Gas Turbine ◽

Soot Formation ◽

Flame Temperature ◽

Fuel Composition ◽

Gas Turbine Combustors

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Flame Stabilization and Emission Characteristics of a Prototype Gas Turbine Burner at Atmospheric Conditions

Volume 4B: Combustion, Fuels and Emissions ◽

10.1115/gt2016-57336 ◽

2016 ◽

Author(s):

Atanu Kundu ◽

Jens Klingmann ◽

Arman Ahamed Subash ◽

Robert Collin

Keyword(s):

Gas Turbine ◽

Reaction Zone ◽

Vector Fields ◽

Thermal Power ◽

Flame Structure ◽

Flame Temperature ◽

Flame Stabilization ◽

Atmospheric Conditions ◽

Pilot Fuel ◽

Co Emission

In the present work, a downscaled prototype 4th generation Dry Low Emission gas turbine (SGT-750) burner (designed and manufactured by Siemens Industrial Turbomachinery AB, Sweden) was investigated using an atmospheric experimental facility. The primary purpose of the research is to analyze flame stability and emission capability of the burner. OH Planar Laser-Induced Fluorescence (OH-PLIF), and chemiluminescence imaging were performed to characterize the flame structure and location. From the OH-PLIF images, the reaction zone and post flame region could be identified clearly. The chemiluminescence images provide an estimation of the overall heat release from the secondary combustion zone inside the Quarl. Emission was measured using a water-cooled emission probe, placed at the exit of the combustor to sample NOx and CO concentrations. The global equivalence ratio (Φ) was varied from rich to lean limit (flame temperature change from 1950 K to 1570 K) for understanding the stable and instable reaction zones inside the Quarl. Total thermal power was varied from 70 kW to 140 kW by changing global Φ and burner throat velocity (60 to 80 m/s). Near the lean blowout (LBO) event (at global Φ ∼ 0.4), instability of reaction zone is revealed from the flame images. Incorrect modulation of Pilot and RPL fuel splits show instable flame. Flame instability mitigation was possible using higher amount of RPL and Pilot fuel (trade-off with emission performance). The main flame LBO margin was extended by applying higher Pilot fuel and using higher preheat air temperature. Numerical analysis was carried out using Fluent to understand the scalar and vector fields. A basic chemical reactor network model was developed to predict the NOx and CO emission with experimental results. NOx emission prediction showed good agreement with experiment; whereas the model is failed to capture accurate CO emission in the lean operating points.

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Catalytic Combustion Technology Development for Gas Turbine Engine Applications

MRS Proceedings ◽

10.1557/proc-549-93 ◽

1998 ◽

Vol 549 ◽

Cited By ~ 1

Author(s):

Robert N. Carter ◽

Lance L. Smith ◽

Hasan Karim ◽

Marco Castaldi ◽

Shah Etemad ◽

...

Keyword(s):

Gas Turbine ◽

Catalytic Combustion ◽

Materials Science ◽

Technology Development ◽

Flame Temperature ◽

Oxides Of Nitrogen ◽

Nox Formation ◽

Turbine Engine ◽

Lean Premixed ◽

Homogeneous Combustion

AbstractCatalytic combustion is one means of meeting increasingly strict emissions requirements for ground-based gas turbine engines for power generation. In conventional homogeneous combustion, high flame temperatures and incomplete combustion lead to emissions of oxides of nitrogen (NOx) and carbon monoxide (CO), and in lean premixed systems unburned hydrocarbons (UHC). However, catalyst-assisted reaction upstream of a lean premixed homogeneous combustion zone can increase the fuel/air mixture reactivity sufficiently to provide low CO/UHC emissions. Additionally, catalytic combustion extends the lean limit of combustion, thereby minimizing NOx formation by lowering the adiabatic flame temperature. An overview of this technology is presented including discussion of the many materials science and catalyst challenges that catalytic combustion poses ranging from the need for high temperature materials to catalyst performance and endurance. Results of ongoing development efforts at Precision Combustion, Inc. (PCI) are presented including modeling studies and experimental results from both bench-scale and combustor-scale studies.

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Effect of Water Injection into Aero-derivative Gas Turbine Combustors on NOx Reduction

European Journal of Engineering Research and Science ◽

10.24018/ejers.2020.5.11.2180 ◽

2020 ◽

Vol 5 (11) ◽

pp. 1357-1359

Author(s):

Roupa Agbadede ◽

Biweri Kainga

Keyword(s):

Gas Turbine ◽

Gas Turbines ◽

Nox Reduction ◽

Water Injection ◽

Flame Temperature ◽

Combustion Process ◽

Heat Rate ◽

Simulation Software ◽

Oxides Of Nitrogen ◽

Fuel Ratio

Oxides of Nitrogen (NOx) generated from gas turbines causes enormous harm to human health and the environment. As a result, different methods have been employed to reduce NOx produced from gas turbine combustion process. One of such technique is the injection of water or steam into the combustion chamber to reduce the flame temperature. A twin shaft aero-derivative gas turbine was modelled and simulated using GASTURB simulation software. The engine was modelled after the GE LM2500 class of gas turbine engines. Water injection into the gas turbine combustor was simulated by implanting water-to-fuel ratios of 0 to 0.8, in an increasing order of 0.2. The results show that when water-to-fuel ratio was increased, the Nox severity index reduced. While heat rate and fuel flow increased with water-to-fuel ratio (injection flow rate).

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