Dilution effects of superheated water vapor on turbulent premixed flames at high pressure and high temperature

Kobayashi, Haruo; Yata, Soichiro; Ichikawa, Yasuhisa; Ogami, Yasuhiro

doi:10.1016/j.proci.2008.05.078

Cited by 37 publications

(20 citation statements)

References 12 publications

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“…The insulation of the burner with ceramic fibers reduces heat losses to reach preheating temperatures up to 480K at low mass flow rates. All parts of the burner are sufficiently superheated to avoid the red spots and the red chemiluminescence typical of a non-uniform wet water vapor [7]. Typical pictures of prismatic flames are shown in Fig.…”

Section: Experimental Set-upmentioning

confidence: 99%

“…Bunsen burners have also been used in the past to study H 2 -air-steam burning velocities by Koroll et Mulpuru [6]. Kobayashi et al [7] made use of a larger Bunsen burner to study the turbulent flame speed at wet conditions and high pressures with φ = 0.9. In [29], Seiser et Seshradi evidenced that steam facilitates the extinction of stoichiometric premixed flames using a counterflow burner.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of burning velocities of ultra-wet methane–air–steam mixtures

Albin

Nawroth

Göke

et al. 2013

Fuel Processing Technology

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Global burning velocities of methane-air-steam mixtures are measured on prismatic laminar Bunsen flames and lifted turbulent V-flames for various preheating temperatures, equivalence ratios and steam mixture fractions at atmospheric pressure. Experiments are conducted on a new rectangular slot-burner. Experimental burning velocities are compared to computed flame speeds of one dimensional adiabatic premixed flames using detailed mechanisms (Konnov 0.5 and GRI Mech 3.0). Mean profiles of radicals OH * are also extracted from these flames and compared to simulation results.

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Section: Experimental Set-upmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of burning velocities of ultra-wet methane–air–steam mixtures

Albin

Nawroth

Göke

et al. 2013

Fuel Processing Technology

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“…Park et al [16] found that with the increase of steam addition, CO first increased, and then decreased, after reaching a maximum value. Kobayashi et al [17] found that the steam is effective for reducing CO and they presumed the CO reduction was probably led by the elementary reactions in the water-gas-shift reaction, i.e., CO + H 2 O → CO 2 + H 2 .…”

Section: Introductionmentioning

confidence: 99%

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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“…It affects the reaction kinetics by changing the concen trations of the chain branching species O, OH, and H [6]; this is also involved in the NOx formation. For rel atively low degrees of steam dilution, Kobayashi et al [10] inves tigated the emission formation in a premixed methane-air flame. For a natural gas diffusion flame, Zhao et al [7] found that steam leads to higher emissions through the thermal pathway but is constrained as a whole by significantly lower prompt NOx.…”

Section: Introductionmentioning

confidence: 99%

“…Whereas some authors state that steam injection increases CO emissions [11], others found that CO is not affected by steam [12] or is even slightly reduced [13]. [10], the authors find that CO is reduced stronger with pressure at wet conditions, which they explain by higher OH concentrations due to the high third body collision efficiency of the steam. [10], the authors find that CO is reduced stronger with pressure at wet conditions, which they explain by higher OH concentrations due to the high third body collision efficiency of the steam.…”

Section: Introductionmentioning

confidence: 99%

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

Göke

Schimek

Steffen

et al. 2014

Journal of Engineering for Gas Turbines and Power

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C h ris tia n O liv e r P a s c h e r e it1In flu en ce of Pressure and S team D ilu tio n on NOx and CO Em issions in a P rem ixed N atu ral Gas F lam eIn the current study, the influence o f pressure and steam on the emission formation in a premixed natural gas flame is investigated at pressures between 1.5 bar and 9 bar. A pre mixed, swirl-stabilized combustor is developed that provides a stable flame up to very high steam contents. Combustion tests are conducted at different pressure levels fo r equivalence ratios from lean blowout to near-stoichiometric conditions and steam-to-air mass ratios from 0% to 25%. A reactor network is developed to model the combustion process. The simulation results match the measured NOx and CO concentrations very well fo r all operating conditions. The reactor network is used fo r a detailed investigation o f the influence o f steam and pressure on the NOx formation pathways. In the experi ments, adding 20% steam reduces NOx and CO emissions to below 10 ppm at all tested pressures up to near-stoichiometric conditions. Pressure scaling laws are derived: CO changes with a pressure exponent o f approximately -0.5 that is not noticeably affected by the steam. For the NOx emissions, the exponent increases with equivalence ratio from 0.1 to 0.65 at dry conditions. At a steam-to-air mass ratio o f 20%, the NOx pressure expo nent is reduced to -0.1 to +0.25. The numerical analysis reveals that steam has a strong effect on the combustion chemistry. The reduction in NOx emissions is mainly caused by lower concentrations o f atomic oxygen at steam-diluted conditions, constraining the ther mal pathway. plants [1,2] but with lower installation costs and emission levels [3]. In contrast to the complex combined-cycle plants, ultra wet gas turbines have a substantially smaller footprint. Depending on the cycle configuration, short start-up times and excellent load control capabilities can be achieved. Furthermore, the high steam content allows for low-NOx, near-stoichiometric combustor oper ation and, thus, enables postcombustion CO2 capture at low cost, since the concentration of CO2 reaches the highest possible value for air breathing gas turbines after condensation of the steam. It was recently shown for a lean premixed and for a rich-quenchlean combustor, that steam dilution significantly reduces NOx

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Dilution effects of superheated water vapor on turbulent premixed flames at high pressure and high temperature

Cited by 37 publications

References 12 publications

Experimental investigation of burning velocities of ultra-wet methane–air–steam mixtures

Experimental investigation of burning velocities of ultra-wet methane–air–steam mixtures

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

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

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