An Experimental Study of Flame Characteristics of Jet Diffusion Flames in Cylindrical Furnaces (3rd Report, Effect of Flow Field on NOx Emission Properties)

Nada, Yuzuru; Parwatha, I Gede; Fukushige, Shingo; Noda, Susumu

doi:10.1299/kikaib.74.707

Cited by 3 publications

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“…Recent attempts using this technique have shown the efficiency of the recirculation of combustion products to reduce NO x emissions. 19,20 With this technique, the burned gases are recirculated inside the combustion chamber and introduced into the flame, which permits a radical reduction of NO x emissions with compact equipment and at low cost. 21 However, NO x emissions from a burner with separated jets and the effects of the size of the recirculation zone of burned gases in such a burner have not yet been studied.…”

Section: Introductionmentioning

confidence: 99%

“…To reduce NO x emissions, various theoretical and technological directions have been explored, such as the effect of the flame temperature, − the influence of the flame strain, − or the flame radiation. − Many studies dealing with NO x emissions have focused on diffusion flames; − this kind of flame can be of great interest in the reduction of NO x emissions if the combustion is coupled with the recirculation of burned gases in the combustion chamber. Recent attempts using this technique have shown the efficiency of the recirculation of combustion products to reduce NO x emissions. , With this technique, the burned gases are recirculated inside the combustion chamber and introduced into the flame, which permits a radical reduction of NO x emissions with compact equipment and at low cost . However, NO x emissions from a burner with separated jets and the effects of the size of the recirculation zone of burned gases in such a burner have not yet been studied.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Burned Gas Recirculation on NO_x Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

2012

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Strict regulations of NO x emission standards have resulted in an optimized performance of combustion chambers. The present paper describes the effects of burned gas recirculation on NO x emissions from hythane−oxygen flames in a separated jet burner. Burners with separated fuel and oxidizer jets permit a high dilution of reactants and a large recirculation zone of burned gases in the combustion chamber, which favors the decrease of nitrogen oxide emissions. In this study, the oxyfuel burner was equipped with two nozzles: the first nozzle supplied a hythane flow (a mixture of natural gas and hydrogen), and the second nozzle supplied pure oxygen. The hydrogen content in the fuel varied from 0 to 20% in volume. The influence of the distance between the nozzles (12−100 mm) and the global equivalence ratio of the mixture was analyzed. Measurements of combustion product concentrations were carried out at the combustion chamber exit using a water-cooled probe and a NO x analyzer. The velocity fields and the size of the recirculation zone were determined by the particle image velocimetry (PIV) technique in the reacting flow. The results showed that an increase in the size of the recirculation zone leads to a decrease in NO x emissions (up to 96%) and that NO x emissions are inversely proportional to the measured surface area of the burned gas recirculation zone. Because of the reaction between recirculated CO 2 and thermal NO and its chemical effects, NO x emissions decrease in lean combustion because of the destruction of NO.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Burned Gas Recirculation on NO_x Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

2012

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NO emission characteristics and aerodynamic structure of a self-recirculation type burner for small boilers

Shinomori¹,

Katou

Shimokuri

et al. 2011

Proceedings of the Combustion Institute

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Effect of the distance between fuel and oxidizer nozzles on NOx emissions from spray combustion furnaces incorporating high-temperature preheated oxidizers

Nada

Shibata

Imaoka

et al. 2015

JTST

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The objective of the present study was to investigate the effect of the distance between fuel and oxidizer nozzles on NOx emissions from a laboratory-scale spray combustion furnace simulating an industrial high-temperature air combustion (HiTAC) furnace. The furnace employed in these trials was fueled with commercially obtainable kerosene in combination with highly preheated oxidizer gases. The oxidizer was pre-diluted by the addition of nitrogen in order to produce dilution levels equivalent to those in industrial HiTAC furnaces. The resulting NOx measurements indicate a trend opposite to that reported by previous studies, such that increasing the distance between the nozzles increases the NOx emissions, and a theory is advanced to explain this unusual observation. In a furnace within which the nozzle distance in the burner is small, the properties of the oxidizer supplied from the nozzle located near the spray nozzle greatly affect NOx emissions. The use of an oxidizer with a much lower preheat temperature and a lower O 2 concentration induces flame lifting further downstream, which significantly reduces NOx emissions through the formation of an invisible flame exhibiting a uniform temperature distribution throughout the furnace. In contrast, in a furnace in which the burner has a large nozzle distance, a highly luminous flame is anchored near the spray nozzle exit due to ignition of fuel vapor by high-temperature burned gases recirculated to the lower section of the furnace. This flame represents a zone with high combustion intensity and generates significant NOx emissions. In such cases, the influence of the oxidizer properties is moderated due to the widely separated nozzle locations.

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An Experimental Study of Flame Characteristics of Jet Diffusion Flames in Cylindrical Furnaces (3rd Report, Effect of Flow Field on NOx Emission Properties)

Cited by 3 publications

References 0 publications

Effects of Burned Gas Recirculation on NO_x Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

Effects of Burned Gas Recirculation on NO_x Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

NO emission characteristics and aerodynamic structure of a self-recirculation type burner for small boilers

Effect of the distance between fuel and oxidizer nozzles on NOx emissions from spray combustion furnaces incorporating high-temperature preheated oxidizers

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An Experimental Study of Flame Characteristics of Jet Diffusion Flames in Cylindrical Furnaces (3rd Report, Effect of Flow Field on NOx Emission Properties)

Cited by 3 publications

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Effects of Burned Gas Recirculation on NOx Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

Effects of Burned Gas Recirculation on NOx Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

NO emission characteristics and aerodynamic structure of a self-recirculation type burner for small boilers

Effect of the distance between fuel and oxidizer nozzles on NOx emissions from spray combustion furnaces incorporating high-temperature preheated oxidizers

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Effects of Burned Gas Recirculation on NO_x Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets

Effects of Burned Gas Recirculation on NO_x Emissions from Natural Gas–Hydrogen–Oxygen Flames in a Burner with Separated Jets