Effect of Operational Parameters on Combustion and Emissions in an Industrial Gas Turbine Combustor

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Mohsen D. Emami ◽  
Hamidreza Shahbazian ◽  
Bengt Sunden
Keyword(s):  
Gas Turbine ◽  
Mixture Fraction ◽  
Flow Characteristics ◽  
Combustion Efficiency ◽  
Fuel Temperature ◽  
Operational Parameters ◽  
Nox Formation ◽  
First Case ◽  
Thermal Nox ◽  
Industrial Gas Turbine

Enhancing a combustion system requires increased combustion efficiency, fuel savings, and reduction of combustion emissions. In this paper, the combustion of CH4 in the combustor of an industrial gas turbine is studied and NO and CO formation/emission is simulated numerically. The objective of the current work is to investigate the influence of combustive parameters and varying the percentage of distributed air flow rate via burning, recirculation, and dilution zone on the reactive flow characteristics, NOx and CO emissions. The governing equations of mass, momentum, energy, turbulence quantities Renormalized group (RNG) (k–ε), mixture fraction and its variance are solved by the finite volume method. The formation and emission of NOx is numerically simulated in a postprocessing fashion, due to the low concentration of the pollutants as compared to the main combustion species. The present work focuses on different physical mechanisms of NOx formation. The thermal-NOx and prompt-NOx mechanism are considered for modeling the NOx source term in the transport equation. Results show that in a gaseous-fueled combustor, the thermal NOx is the dominant mechanism for NOx formation. Particularly, the simulation provides more insight into the correlation between the maximum combustor temperature, exhaust average temperatures, and the thermal NO concentration. Results indicate that the exhaust temperature and NOx concentration decrease while the excess air factor increases. Moreover, results demonstrate that as the combustion air temperature increases, the combustor temperature increases and the thermal NOx concentration increases dramatically. Furthermore, results demonstrate that the NO concentration at the combustor exit is at maximum value in a swirl angle of 55 deg and a gradual rise in the NOx concentration is detected as the combustion fuel temperature increases. In addition, results demonstrate that the air distribution of the first case at laboratory conditions is optimal where the mass fractions of NO and CO are minimum.

Investigation of Flamelet Generated Manifold Reaction Source Term Closure Models Applied to an Industrial Gas Turbine

2019 ◽  
Author(s):  
George Mallouppas ◽  
Graham Goldin ◽  
Yongzhe Zhang ◽  
Piyush Thakre ◽  
Jim Rogerson
Keyword(s):  
Gas Turbine ◽  
Source Term ◽  
Mixture Fraction ◽  
Turbulent Flame ◽  
Flame Speed ◽  
Turbulent Flame Speed ◽  
Progress Variable ◽  
Flamelet Generated Manifold ◽  
Reactor Types ◽  
Industrial Gas Turbine

Abstract Three Flamelet Generated Manifold reaction source term closure options and two different reactor types are examined with Large Eddy Simulation of an industrial gas turbine combustor operating at 3 bar. This work presents the results for the SGT-100 Dry Low Emission (DLE) gas turbine provided by Siemens Industrial Turbomachinery Ltd. The related experimental study was performed at the German Aerospace Centre, DLR, Stuttgart, Germany. The FGM model approximates the thermo-chemistry in a turbulent flame as that in a simple 0D constant pressure ignition reactors and 1D strained opposed-flow premixed reactors, parametrized by mixture fraction, progress variable, enthalpy and pressure. The first objective of this work is to compare the flame shape and position predicted by these two FGM reactor types. The Kinetic Rate (KR) model, studied in this work, uses the chemical rate from the FGM with assumed shapes, which are a Beta function for mixture fraction and delta functions for reaction progress variable and enthalpy. Another model investigated is the Turbulent Flame-Speed Closure (TFC) model with Zimont turbulent flame speed, which propagates premixed flame fronts at specified turbulent flame speeds. The Thickened Flame Model (TFM), which artificially thickens the flame to sufficiently resolve the internal flame structure on the computational grid, is also explored. Therefore, a second objective of this paper is to compare KR, TFC and TFM with the available experimental data.

One-Dimensional Model to Quantify NOx Reduction in Gas Turbines Using EGR

1998 ◽  
Author(s):  
K. K. Botros ◽  
M. J. de Boer ◽  
G. Kibrya
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Nox Reduction ◽  
Simulation Software ◽  
Specific Work ◽  
Dimensional Model ◽  
Nox Formation ◽  
One Dimensional ◽  
Thermal Nox

A one dimensional model based on fundamental principles of gas turbine thermodynamics and combustion processes was constructed to quantify the principle of exhaust gas recirculation (EGR) for NOx reduction. The model utilizes the commercial process simulation software ASPEN PLUS®. Employing a set of 8 reactions including the Zeldovich mechanism, the model predicted thermal NOx formation as function of amount of recirculation and the degree of recirculate cooling. Results show that addition of sufficient quantities of uncooled recirculate to the inlet air (i.e. EGR>∼4%) could significantly decrease NOx emissions but at a cost of lower thermal efficiency and specific work. Cooling the recirculate also reduced NOx at lower quantities of recirculation. This has also the benefit of decreasing losses in the thermal efficiency and in the specific work output. Comparison of a ‘rubber’ and ‘non-rubber’ gas turbine confirmed that residence time is one important factor in NOx formation.

Structural Design and High-Pressure Test of a Ceramic Combustor for 1500°C Class Industrial Gas Turbine

1997 ◽  
Vol 119 (3) ◽  
pp. 506-511 ◽  
Author(s):  
I. Yuri ◽  
T. Hisamatsu ◽  
K. Watanabe ◽  
Y. Etori
Keyword(s):  
Fracture Toughness ◽  
High Pressure ◽  
Gas Turbine ◽  
Structural Design ◽  
Metal Structure ◽  
Combustion Efficiency ◽  
Test Results ◽  
Industrial Gas Turbine ◽  
Hybrid Ceramic ◽  
Load Conditions

A ceramic combustor for a 1500°C, 20 MW class industrial gas turbine was developed and tested. This combustor has a hybrid ceramic/metal structure. To improve the durability of the combustor, the ceramic parts were made of silicon carbide (SiC), which has excellent oxidation resistance under high-temperature conditions as compared to silicon nitride (Si3N4), although the fracture toughness of SiC is lower than that of Si3N4. Structural improvements to allow the use of materials with low fracture toughness were made to the fastening structure of the ceramic parts. Also, the combustion design of the combustor was improved. Combustor tests using low-Btu gaseous fuel of a composition that simulated coal gas were carried out under high pressure. The test results demonstrated that the structural improvements were effective because the ceramic parts exhibited no damage even in the fuel cutoff tests from rated load conditions. It also indicated that the combustion efficiency was almost 100 percent even under part-load conditions.

scholarly journals Technical Applicability of Low-Swirl Fuel Nozzle for a Liquid-Fueled Industrial Gas Turbine Combustor

2012 ◽  
Author(s):  
Masamichi Koyama ◽  
Shigeru Tachibana
Keyword(s):  
Gas Turbine ◽  
Flow Characteristics ◽  
Axial Direction ◽  
Flame Stabilization ◽  
Axial Position ◽  
Axial Distance ◽  
Gas Turbine Combustor ◽  
Lifted Flame ◽  
Fuel Nozzle ◽  
Industrial Gas Turbine

This paper explores the technical applicability of a low-swirl fuel nozzle designed for use with a liquid-fueled industrial gas turbine combustor. Particle image velocimetry was applied to measure nozzle flow fields with an open methane-air premixed flame configuration. Herein we discuss the effects of the chamfer dimensions of the nozzle tip on flow characteristics. The profiles indicate parallel shifts in axial direction that depend on chamfer dimensions. When velocity is normalized by bulk velocity and plotted against axial distance from the virtual origins, the profiles are consistent. This means that chamfer dimensions primarily affect the axial position of the flame, while keeping other flow characteristics, such as global stretch rate, unchanged. Then, the atmospheric combustion test was conducted with kerosene in a single-can combustor. Lifted flame stabilization was confirmed by observing the flames through a window. Lastly, an engine test was performed to assess the technical applicability of the fuel nozzle under real engine conditions. The engine testbed was a 290 kW simple-cycle liquid-fueled gas turbine engine. The configurations of the fuel nozzle were consistent with the ones used in the PIV and the atmospheric combustion test. Wall temperatures close to the fuel nozzle exit were within the acceptable range, even without the cooling air required with conventional combustors. This is an advantage of the lifted flame stabilization technique. NOx emissions were below maximum levels set under current Japanese regulations (<84 ppm@15% O2). In sum, the proposed fuel nozzle design shows promise for use with liquid-fueled industrial gas turbine engines.

Investigation on Reaction Flow Field of Low Emission TAPS Combustors

2014 ◽  
Vol 694 ◽  
pp. 45-48
Author(s):  
Qun Zhang ◽  
Hua Sheng Xu ◽  
Tao Gui ◽  
Shun Li Sun ◽  
Yue Wu ◽  
...  
Keyword(s):  
Combustion Process ◽  
Combustion Efficiency ◽  
Combustion Model ◽  
Outlet Temperature ◽  
Gas Temperature ◽  
Distribution Factor ◽  
Two Phase ◽  
Nox Formation ◽  
Low Emission ◽  
Thermal Nox

A twin annular premixing swirler (TAPS) combustor model of low emissions was developed in this study. And computational studies on combustion process in the combustor model were carried out. Standard k-ε Turbulence Model, PDF non-premixed combustion model, Zeldovich thermal NOx formation model and DPM two-phase model were employed. The distributions of some key performance parameters such as gas temperature, flow velocity, concentrations of NOx and CO emissions were obtained and analyzed. At the same time, combustion mechanics inside the TAPS combustor model were investigated. The computational results indicated that the TAPS combustor employed in this study does a better job of improving key combustion performances such as combustion efficiency, total pressure recovery and outlet temperature distribution factor, and reducing NOx and CO emissions at the same time.

Experimental Analysis of the Combustion Behavior of a Gas Turbine Burner by Laser Measurement Techniques

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Holger Ax ◽  
Ulrich Stopper ◽  
Wolfgang Meier ◽  
Manfred Aigner ◽  
Felix Güthe
Keyword(s):  
Gas Turbine ◽  
Mixture Fraction ◽  
Measurement Techniques ◽  
Elevated Pressure ◽  
Flame Stabilization ◽  
Single Shot ◽  
Laser Raman ◽  
Planar Laser ◽  
Industrial Gas Turbine ◽  
Gas Turbine Burner

Experimental results from optical and laser spectroscopic measurements on a scaled industrial gas turbine burner at elevated pressure are presented. Planar laser induced fluorescence on the OH radical and OH∗ chemiluminescence imaging were applied to natural gas/air flames for a qualitative analysis of the position and shape of the flame brush, the flame front and the stabilization mechanism. The results exhibit two different ways of flame stabilization, a conical more stable flame and a pulsating opened flame. For quantitative results, one-dimensional laser Raman scattering was applied to these flames and evaluated on an average and single-shot basis in order to simultaneously determine the major species concentrations, the mixture fraction, and the temperature. The mixing of fuel and air, as well as the reaction progress, could thus be spatially and temporally resolved, showing differently strong variations depending on the flame stabilization mode and the location in the flame.

Catalytic Partial Oxidation of Natural Gas in Gas Turbine Applications

2013 ◽  
Author(s):  
Arturo Manrique Carrera ◽  
Jeevan Jayasuriya ◽  
Torsten Fransson
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Partial Oxidation ◽  
The Other ◽  
Test Facility ◽  
Catalytic Partial Oxidation ◽  
Other Hand ◽  
Thermal Nox ◽  
Industrial Gas Turbine ◽  
Operational Range

The demands of emissions, combustion efficiency over a wider operational range, and fuel flexibility for industrial gas turbine applications are expected to increase in the coming years. Currently, it is common the use of a stabilizing piloting diffusion flame during part load operation, this flame is accountable for an important part of the thermal NOx emissions on partial load, and in some cases also at full load operation. On the other hand Catalytic Partial Oxidation (CPO) of natural gas is a technique used in petrochemical industry for the Fischer-Tropsch process and for H2 production, and is based in the production of Syn-Gas rich in H2 and CO. The present work explores the possibility to use the CPO of natural gas in industrial gas turbine applications, it is based in experiments performed between 5 and 13 bar using an arrangement of Rh based catalyst and CH4. The experiments were done at the Catalytic Combustion High Pressure Test Facility, at the Royal Institute of Technology (KTH) in Sweden. The gas produced leaves the CPO reactor between 700 and 850 °C and it is rich in H2 and CO. It was found that the most important parameter after reaching the light off temperature in the CPO reactor is the equivalence ratio Φ, which evidences the kinetically controlled regime in the Rh catalyst that depends on O2 availability. The H2/CO ratio is close to the theoretical value of 2 and the selectivity towards H2 and CO are 90% and 95% respectively while the CH4 conversion reached approximately 55%. Pressure on the other hand had a small negative influence in the tested pressure range and it is more relevant at richer fuel conditions (high equivalence ratios). The CPO process had shown that it is relatively easy to control the operation temperature of the catalyst. This temperature is kept below the maximum allowed by reducing the O2 availability. The high temperature Syn-Gas gas produced through CPO process could be burnt in the downstream of the catalysts steadily at flame temperatures below the thermal-NOx threshold. The CPO reactor could provide the flame stabilization function at a wide range of operational conditions, and replace the diffusion piloting flame. This approach could cope with NOx and CO emissions in a wider operational range and offers the possibility of using different fuels as the reaction controlling factor is O2 availability. Furthermore, an initial design of a possible combustion strategy downstream of the CPO reactor is also presented.

scholarly journals One-Dimensional Predictive Emission Monitoring Model for Gas Turbine Combustors

1997 ◽  
Author(s):  
K. K. Botros ◽  
M. J. de Boer ◽  
G. R. Price ◽  
G. Kibrya
Keyword(s):  
Gas Turbine ◽  
Flow Reactor ◽  
Plug Flow ◽  
Flame Length ◽  
Simulation Software ◽  
Nox Formation ◽  
One Dimensional ◽  
Monitoring Model ◽  
Emission Monitoring ◽  
Thermal Nox

Current predictive emission monitoring (PEM) techniques are briefly reviewed and the concept for a general predictive model was favorably evaluated. Utilizing the commercial process simulation software ASPEN PLUS®, a one dimensional model based on fundamental principles of gas turbine thermodynamics and combustion processes was constructed. Employing a set of 22 reactions including the Zeldovich mechanism, the model predicted for thermal NOx formation. It accounted for combustor geometry, dilution air injection along the combustor annulus, convective heat transfer across the liner, flame length, and full-load inlet flows. The combustor was subdivided into slices, each of which was modeled by a plug flow reactor, giving insight into profiles of NOx formation, species concentration and temperature along the combustor’s length, as well as quantifying the residence time in the combustor. The simulation predicted the levels of NOx for a particular gas turbine combustor and determined the effects of various parameters, such as flame length, hydrocarbon conversion ratio and recycle zones.

scholarly journals An Advanced Development of a Second-Generation Dry, Low-NOx Combustor for 1.5MW Gas Turbine

1996 ◽  
Author(s):  
Shin-ichi Kajita ◽  
Shin-ichi Ohga ◽  
Masahiro Ogata ◽  
Satoru Itaka ◽  
Jun-ichi Kitajima ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Second Generation ◽  
Nox Reduction ◽  
Combustion Efficiency ◽  
Combustion System ◽  
Endurance Test ◽  
Industrial Gas Turbine ◽  
Cooling Air ◽  
Cycle Endurance ◽  
Advanced Development

Advanced development of a second-generation dry, low-NOx combustor for KHI’s 1.5MW industrial gas turbine, M1A-13A, is described. In this advanced development, efforts were made mainly to improve combustion efficiency in addition to NOx reduction experimentally. The combustion liner was extended to increase combustion volume, and supplemental burners were installed downstream of multiple main burners to broaden low-NOx operation range. In consequence of the optimization of the fuel allotment, air/fuel ratio at each burner, cooling air, and so on, the engine showed NOx emissions under 15 ppm (15% O2), and a combustion efficiency more than 99.5% over the range between 75% and 100% load. Finally, by means of a 300-hour operation at full load and a 500-cycle endurance test, the total reliability of this combustion system was ensured.

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