A Potential Low NOx Emission Combustor for Gas Turbines Using the Concept of Hybrid Combustion

1977 ◽  
Vol 99 (4) ◽  
pp. 631-637 ◽  
Author(s):  
S. E. Mumford ◽  
W. S. Y. Hung ◽  
P. P. Singh

An experimentally verified NOx emission model has been described previously to predict accurately the NOx emission characteristics of conventional gas turbine combustors as well as laboratory scaled premixed combustor. Experimental data and analyses indicated that a hybrid combustor, which utilizes features of both the conventional and the premixed combustors, has the potential to be a viable low NOx emission combustor. Initial calculations indicated low NOx emission levels for the hybrid combustor. This hybrid combustion concept was tested in the laboratory. The measured NOx emissions from this laboratory-scaled hybrid combustor were in excellent agreement with the analytical predictions. The emissions of carbon monoxide and unburned hydrocarbons were also measured. It has been concluded from an analysis of the measured data that a gas turbine combustor, designed with the hybrid combustion concept, has the best potential to be a near-term viable combustor in meeting the EPA proposed gas turbine emission regulations. The experimental effort thus far has focused on the emission characteristics. Other areas of the design, such as the vaporization of liquid fuels, require additional development work prior to the incorporation of this concept into a viable system for an engine application.

Author(s):  
Juergen Meisl ◽  
Gerald Lauer ◽  
Stefan Hoffmann

This contribution describes the systematic refinement of the hybrid burner used in Siemens Vx4.3A gas turbines for lean premix combustion of various liquid fuels such as Distillate fuel No. 2, Naphtha and Condensate. Additionally to the dry premix operation fuel/water emulsions are used in premix mode for a further reduction of NOx emissions or power augmentation. NOx emissions of less than 72 ppm are already achieved with the HR3 hybrid burner in dry premix mode. These can be reduced to values below of 42 ppm NOx in emulsion mode.


1977 ◽  
Vol 99 (4) ◽  
pp. 575-579
Author(s):  
W. S. Y. Hung

An experimentally verified NOx emission model for gas turbines has been reported previously. The model has been modified to determine the NOx emission levels of various fuels as compared to No. 2 distillate oil. The NOx emission levels of various conventional and unconventional gas turbine fuels of interest are predicted. The predicted NOx emission levels for these fuels, including methanol, ethanol, propane, and hydrogen, are in good agreement with available laboratory and field data from stationary, aircraft, and automotive gas turbine combustors. The predicted results should be applicable to other fuel-lean, heterogeneous combustion systems.


Author(s):  
Vera Hoferichter ◽  
Denise Ahrens ◽  
Michael Kolb ◽  
Thomas Sattelmayer

Staged combustion is a promising technology for gas turbines to achieve load flexibility and low NOx emission levels at the same time. Therefore, a large scale atmospheric test rig has been set up at the Institute of Thermodynamics, Technical University of Munich to study NOx emission characteristics of a reacting jet in hot cross flow. The premixed primary combustion stage is operated at ϕ = 0.5 and provides the hot cross flow. In the second stage a premixed jet at ϕ = 0.77 is injected perpendicular to the first stage. In both stages natural gas is used as fuel and air as oxidant. This paper presents a reactor model approach for the computation of the resulting NOx concentrations. The mixing and ignition process along the jet streamline of maximum NOx formation is simulated using a perfectly stirred reactor with Cantera 1.8. The reactor model is validated for the ambient pressure case using experimental data. Afterwards, a high pressure simulation is performed in order to investigate the NOx emission characteristics under gas turbine conditions. The NOx formation is divided into flame NOx and post flame NOx. The reactor model reveals that the formation of post flame NOx in the second combustion stage can be efficiently suppressed due to fast mixing with cross flow material and the corresponding temperature reduction. Compared to single stage combustion with the same power output, no NOx reduction was observed in the experiment. However, the results from the reactor model suggest a NOx reduction potential at gas turbine conditions caused by the increased influence of post flame NOx production at high pressure.


Author(s):  
Chao Zong ◽  
Yaya Lyu ◽  
Desan Guo ◽  
Chengqin Li ◽  
Tong Zhu

Micro gas turbine is one of the ideal prime movers for small-distributed energy systems. It can effectively reduce the emission of greenhouse gases and nitrogen oxides. Moreover, the use of micro gas turbines will contribute to burning fossil fuels in a much cleaner way. The staged combustion technology is the favorite way for low pollution combustion chamber such like. Therefore, the influence of the proportion of pilot fuel in the combustion chamber on pollutant emission deserves further study. The object of this research is the Double annular swirler (Das), which was applied to a 100 kW micro gas turbine combustion chamber. The combustion performance and emission characteristics under different Pilot Fuel Ratios (PFR) were obtained in prototype experimental system. Under the experimental conditions, Computational fluid dynamics (CFD) method was applied to research the reacting flow field and the formation of NOx in the combustion chamber and then analyze the influences of PFRs on combustion process. Experimental results show that the NOx emission of Das decreased at first and then increased with the augment of PFR. When PFR was near to 11%, the per unit NOx emission concentration reached its minimum. The numerical simulation agreed well with the experimental data. Further analysis of the simulation results indicate that there is a strong correlation between Φlocal and NOx concentration. When it is lower than a certain value, the number of nitrogen oxides will be significantly reduced. The value has a lot to do with the inlet air temperature and the pressure of the combustion chamber under the design condition, and it needs to be confirmed by calculating the adiabatic temperature. Simultaneously, we also find that although the percentage of total air flowing into the combustor remains unchanged, the increase of PFR would reduce the airflow ratio in inner swirler. This implies that for some particular combustion chambers, special attention should be paid to the changes in air allocation caused by PFR.


2012 ◽  
Vol 512-515 ◽  
pp. 2135-2142 ◽  
Author(s):  
Yu Peng Wu ◽  
Zhi Yong Wen ◽  
Yue Liang Shen ◽  
Qing Yan Fang ◽  
Cheng Zhang ◽  
...  

A computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established. The chemical percolation devolatilization (CPD) model, instead of an empirical method, has been adapted to predict the nitrogen release during the devolatilization. The current CFD model has been validated by comparing the simulated results with the experimental data obtained from the boiler for case study. The validated CFD model is then applied to study the effects of ratio of over fire air (OFA) on the combustion and nitrogen oxides (NOx) emission characteristics. It is found that, with increasing the ratio of OFA, the carbon content in fly ash increases linearly, and the NOx emission reduces largely. The OFA ratio of 30% is optimal for both high burnout of pulverized coal and low NOx emission. The present study provides helpful information for understanding and optimizing the combustion of the studied boiler


Author(s):  
Toshiaki Sakurazawa ◽  
Takeo Oda ◽  
Satoshi Takami ◽  
Atsushi Okuto ◽  
Yasuhiro Kinoshita

This paper describes the development of the Dry Low Emission (DLE) combustor for L30A gas turbine. Kawasaki Heavy Industries, LTD (KHI) has been producing relatively small-size gas turbines (25kW to 30MW class). L30A gas turbine, which has a rated output of 30MW, achieved the thermal efficiency of more than 40%. Most continuous operation models use DLE combustion systems to reduce the harmful emissions and to meet the emission regulation or self-imposed restrictions. KHI’s DLE combustors consist of three burners, a diffusion pilot burner, a lean premix main burner, and supplemental burners. KHI’s proven DLE technologies are also adapted to the L30A combustor design. The development of L30 combustor is divided in four main steps. In the first step, Computational Fluid Dynamics (CFD) analyses were carried out to optimize the detail configuration of the combustor. In a second step, an experimental evaluation using single-can-combustor was conducted in-house intermediate-pressure test facility to evaluate the performances such as ignition, emissions, liner wall temperature, exhaust temperature distribution, and satisfactory results were obtained. In the third step, actual pressure and temperature rig tests were carried out at the Institute for Power Plant Technology, Steam and Gas Turbines (IKDG) of Aachen University, achieving NOx emission value of less than 15ppm (O2=15%). Finally, the L30A commercial validation engine was tested in an in-house test facility, NOx emission is achieved less than 15ppm (O2=15%) between 50% and 100% load operation point. L30A field validation engine have been operated from September 2012 at a chemical industries in Japan.


Author(s):  
Bernhard Ćosić ◽  
Frank Reiss ◽  
Marc Blümer ◽  
Christian Frekers ◽  
Franklin Genin ◽  
...  

Abstract Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives. In these applications, liquid fuels like 'Diesel Fuel No.2' can be used either as main fuel or as backup fuel if natural gas is not reliably available. The MAN Gas Turbines (MGT) operate with the Advanced Can Combustion (ACC) system, which is capable of ultra-low NOx emissions for gaseous fuels. This system has been further developed to provide dry dual fuel capability. In the present paper, we describe the design and detailed experimental validation process of the liquid fuel injection, and its integration into the gas turbine package. A central lance with an integrated two-stage nozzle is employed as a liquid pilot stage, enabling ignition and start-up of the engine on liquid fuel only. The pilot stage is continuously operated, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles based on fluidic oscillator atomizers, wherein atomization of the liquid fuel is achieved through self-induced oscillations. We present results illustrating the spray, hydrodynamic, and emission performance of the injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification within full engine tests. We show the design of the fuel supply and distribution system. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000.


Fuel ◽  
2019 ◽  
Vol 237 ◽  
pp. 50-59 ◽  
Author(s):  
Shan Li ◽  
Shanshan Zhang ◽  
Hua Zhou ◽  
Zhuyin Ren

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vedant Dwivedi ◽  
Srikanth Hari ◽  
S. M. Kumaran ◽  
B. V. S. S. S. Prasad ◽  
Vasudevan Raghavan

Abstract Experimental and numerical study of flame and emission characteristics in a tubular micro gas turbine combustor is reported. Micro gas turbines are used for distributed power (DP) generation using alternative fuels in rural areas. The combustion and emission characteristics from the combustor have to be studied for proper design using different fuel types. In this study methane, representing fossil natural gas, and biogas, a renewable fuel that is a mixture of methane and carbon-dioxide, are used. Primary air flow (with swirl component) and secondary aeration have been varied. Experiments have been conducted to measure the exit temperatures. Turbulent reactive flow model is used to simulate the methane and biogas flames. Numerical results are validated against the experimental data. Parametric studies to reveal the effects of primary flow, secondary flow and swirl have been conducted and results are systematically presented. An analysis of nitric-oxides emission for different fuels and operating conditions has been presented subsequently.


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