Low NOx emission characteristics of refuse-recovered low BTU gases as fuel for high efficiency gas turbines

1989 ◽  
Vol 13 (1) ◽  
pp. 53-61 ◽  
Author(s):  
P. S. Pak ◽  
Y. Suzuki
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.


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


2013 ◽  
Vol 318 ◽  
pp. 371-374
Author(s):  
Chen Fan

There was a conflict between NOx emission and engine power of modified natural gas engine. Influence facters of NOx emission and emission characteristics of existing modified engine were studied. Emission and engine power of natural gas engine modified from gasoline and diesel engine were compared. Then some sugesstion are brought out for designing low NOx emission natural gas engine and promote engine power.


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.


1990 ◽  
Author(s):  
Satoru Goto ◽  
Yasuhiro Itoh ◽  
Yutaka Higuchi ◽  
Tateo Nagai

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.


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.


Author(s):  
Ainan Bao ◽  
Dexin Wang ◽  
William Liss

To achieve ultra low NOx emission as well as high efficiency for industrial burners, premixed or partial premixed combustion technology is becoming more attractive than flue gas recirculation approaches, which tend to cause low combustion stability and low energy use efficiency. A well designed premixed combustion system can achieve lower and more uniform combustion zone temperatures thus resulting in reduced thermal NOx generation. A multi-stage premixed industrial scale gas burner with oil backup capability has been developed by the authors, with the assistance from CFD simulation. By using staged combustion, combustion heat release is better distributed into a larger volume to avoid high peak flame temperature zone to occur. By using a primary stage combustion with a fuel rich flame and a hot high emissive metallic chamber wall, the burner combustion stability is ensured. The CFD tool was used to simulate and optimize the whole burner combustion and heat transfer process, with proper fluid dynamics and reaction models for this full size burner development. With the CFD efforts, the final burner design can achieve a very uniform temperature field, with peak flame temperatures below 1650°C, therefore thermal NOx generation is minimized. The numerical results show that this new gas-fired burner can achieve high efficiency with low NOx emission. Using the CFD simulation tool, the burner global parameters, such as its peak flame temperatures, its exhaust flue gas temperatures, and its NOx concentration distributions, have been studied under different burner operation conditions, e.g., different excess air levels, different burner firing rates, and different mixture inlet temperatures. The CFD simulation tool has been proved a good assistance for the burner design, as well as the burner performance optimization.


2013 ◽  
Vol 388 ◽  
pp. 292-297 ◽  
Author(s):  
Seyed Ehsan Hosseini ◽  
Mazlan A. Wahid ◽  
Saber Salehirad

In recent years global fuel consumption has increased in the world due to modernization and progress in the standard of living. The conspicuous rate of carbon dioxide and nitrogen oxide released to the environment and fuel resources are depleted day by day due to inconsiderate fuel consumption. Requirement for efficient use of any kinds of fuel has become the other concern due to the oil crisis and limitation of fuel resources. In combustion process, the abatement of pollutants often associates with efficiency loss. In the other word, high efficiency and low pollutant which are the main requirements of combustion are not fulfilled by the existing combustion. Today, flameless combustion has received more attention because of its low NOx emission and significant energy saving. Generally, compatibility between high performance and low NOx emission has been observed by preheated air application and changing the combustion characteristics from traditional flame to flameless mode. This paper aims to review the concepts and the applications of flameless combustion and gathers useful information to understand the necessity of transient from traditional flame mode to flameless combustion.


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