Influence of Pressure and Steam Dilution on NOx and CO Emissions in a Premixed Natural Gas Flame

It is generally accepted that combustion of hydrogen and natural gas mixtures will become more prevalent in the near future, to allow for a further penetration of renewables in the European power generation system. The current work aims at the demonstration of the advantages of steam dilution, when highly reactive combustible mixtures are used in a swirl-stabilized combustor. To this end, high-pressure experiments have been conducted with a generic swirl-stabilized combustor featuring axial air injection to increase flashback safety. The experiments have been conducted with two fuel mixtures, at various pressure levels up to 9 bar and at four levels of steam dilution up to 25% steam-to-air mass flow ratio. Natural gas has been used as a reference fuel, whereas a mixture of natural gas and hydrogen (10% hydrogen by mass) represented an upper limit of hydrogen concentration in a natural gas network with hydrogen enrichment. The results of the emissions measurements are presented along with a reactor network model. The latter is applied as a means to qualitatively understand the chemical processes responsible for the observed emissions and their trends with increasing pressure and steam injection.

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“…with p 0 being a reference pressure and α, the scaling exponent. This scaling law was shown to be applicable at steam diluted conditions [23].…”

Section: No X Emissionsmentioning

confidence: 86%

Emissions of a Wet Premixed Flame of Natural Gas and a Mixture With Hydrogen at High Pressure

Stathopoulos

Kuhn

Wendler

et al. 2016

Journal of Engineering for Gas Turbines and Power

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“…3, left panel). Given that the main sources of NO x emission, i.e., coal combustion from coal power plants, industrial manufacturing processes, fuel burning from motor vehicles, and natural gas burning (Göke et al, 2014), are relatively the same for all four seasons, the contribution of scattered coal heating or central heating boilers without denitrification devices to the increase of NO − 3 concentrations during winter cannot be ignored. The lower height of the planetary boundary layer during the winter is another reason for the high concentrations during winter.…”

Section: Winter Concentrations and Year-long Aerosol Pollutionmentioning

confidence: 99%

Changes in chemical components of aerosol particles in different haze regions in China from 2006 to 2013 and contribution of meteorological factors

et al. 2015

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Abstract. Since there have been individual reports of persistent haze-fog events in January 2013 in central-eastern China, questions on factors causing the drastic differences in changes in 2013 from changes in adjacent years have been raised. Changes in major chemical components of aerosol particles over the years also remain unclear. The extent of meteorological factors contributing to such changes is yet to be determined. The study intends to present the changes in daily based major water-soluble constituents, carbonaceous species, and mineral aerosol in PM 10 at 13 stations within different haze regions in China from 2006 to 2013, which are associated with specific meteorological conditions that are highly related to aerosol pollution (parameterized as an index called Parameter Linking Aerosol Pollution and Meteorological Elements -PLAM). No obvious changes were found in annual mean concentrations of these various chemical components and PM 10 in 2013, relative to 2012. By contrast, wintertime mass of these components was quite different. In Hua Bei Plain (HBP), sulfate, organic carbon (OC), nitrate, ammonium, element carbon (EC), and mineral dust concentrations in winter were approximately 43, 55, 28, 23, 21, and 130 µg m −3 , respectively; these masses were approximately 2 to 4 times higher than those in background mass, which also exhibited a decline during 2006 to 2010 and then a rise till 2013. The mass of these concentrations and PM 10 , except minerals, respectively, increased by approximately 28 to 117 % and 25 % in January 2013 compared with that in January 2012. Thus, persistent haze-fog events occurred in January 2013, and approximately 60 % of this increase in component concentrations from 2012 to 2013 can be attributed to severe meteorological conditions in the winter of 2013. In the Yangtze River Delta (YRD) area, winter masses of these components, unlike HBP, have not significantly increase since 2010; PLAM were also maintained at a similar level without significant changes. In the Pearl River Delta (PRD) area, the regional background concentrations of the major chemical components were similar to those in the YRD, accounting for approximately 60-80 % of those in HBP. Since 2010, a decline has been found for winter concentrations, which can be partially attributable to persistently improving meteorological conditions and emission cutting with an emphasis on coal combustion in this area.

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“…A CCD camera (D70s, Nikon, Tokyo, Japan) equipped with an AF Nikkor lens (50 mm/F1.8D, Nikon, Tokyo, Japan) and a band-pass CH filter (430/10, LaVision, Göttingen, Germany) was used to record the time-averaged CH chemiluminescence images for CH 4 /air and CH 4 /air/steam flames. All the images were recorded with an exposure time of 0.77 s and a resolution of 3008 × 2000 pixels.…”

Section: Flame Visualization With the Ch Chemiluminescence Imagingmentioning

confidence: 99%

“…Kuhn et al studied the influence of steam addition with different fuels, and they found that, in order to prevent lean blowout event, higher equivalence ratios are required with increasing steam addition [18]. Göke et al [4] studied the steam influence with a premixed natural gas flame at different pressures. Their results indicated that the higher steam to air mass ratio leads to a higher blowout equivalence ratio, and no stable flame was achieved above a maximum steam to air mass ratio.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the steam-diluted combustion can be combined with the CCS (carbon capture and storage) and applied as an environmentally-friendly technology to reduce the greenhouse emissions (mainly CO 2 ). In this combined technology, the gas turbine combustion operates with sufficient steam dilution to extend the operability limits of low NO x to near-stoichiometric operating conditions [3,4], where the CO 2 concentration in the combustion exhaust achieves the theoretical maximum value for the combustion of hydrocarbon fuel in air-breathing gas turbines. After a steam condensation process, the CO 2 purity in the exhaust is sufficiently high, which makes the post-combustion capture of CO 2 into a feasible technology for practical application with an affordable cost.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Steam Addition on Premixed Methane Air Combustion at Atmospheric Pressure

Tong

Thern

et al. 2017

Energies

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Steam-diluted combustion in gas turbine systems is an effective approach to control pollutant emissions and improve the gas turbine efficiency. The primary purpose of the present research is to analyze the influence of steam dilution on the combustion stability, flame structures, and CO emissions of a swirl-stabilized gas turbine model combustor under atmospheric pressure conditions. The premixed methane/air/steam flame was investigated with three preheating temperatures (384 K/434 K/484 K) and the equivalence ratio was varied from stoichiometric conditions to the flammability limits where the flame was physically blown out from the combustor. In order to represent the steam dilution intensity, the steam fraction Ω defined as the steam to air mass flow rate ratio was used in this work. Exhaust gases were sampled with a water-cooled emission probe which was mounted at the combustor exit. A 120 mm length quartz liner was used which enabled the flame visualization and optical measurement. Time-averaged CH chemiluminescence imaging was conducted to characterize the flame location and it was further analyzed with the inverse Abel transform method. Chemical kinetics calculation was conducted to support and analyze the experimental results. It was found that the LBO (lean blowout) limits were increased with steam fraction. CH chemiluminescence imaging showed that with a high steam fraction, the flame length was elongated, but the flame structure was not altered. CO emissions were mapped as a function of the steam fraction, inlet air temperature, and equivalence ratios. Stable combustion with low CO emission can be achieved with an appropriate steam fraction operation range.

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Influence of Pressure and Steam Dilution on NOx and CO Emissions in a Premixed Natural Gas Flame

Cited by 12 publications

References 0 publications

Emissions of a Wet Premixed Flame of Natural Gas and a Mixture With Hydrogen at High Pressure

Emissions of a Wet Premixed Flame of Natural Gas and a Mixture With Hydrogen at High Pressure

Changes in chemical components of aerosol particles in different haze regions in China from 2006 to 2013 and contribution of meteorological factors

Influence of the Steam Addition on Premixed Methane Air Combustion at Atmospheric Pressure

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