A Study on Radiation Heat Transfer and Characteristics of Oxygen Enriched Double Inversed Diffusion Flame

Lee, Sung-Ho,Hwang, Sang-Soon The Korean Society of Combustion 2001 한국연소학회지 Vol.6 No.2

An experimental study of oxygen enriched double inversed diffusion flame was conducted to understand the flame characteristics and radiation heat transfer. The infrared radiation meter was used to measure of various combination of fuel, air and pure oxygen. The results show that oxygen enriched double inversed diffusion flame is very effective to increase of thermal radiation and proper addition of pure oxygen in air flow can intensify thermal radiation of flame. And it can be found that oxygen enriched double inversed diffusion flame could give benefits of cost effective and very high energy.

A Study on the Characteristics of Oxygen-Enriched Air Gasification for Fluff SRF in the Downdraft Type Fixed Bed Reactor

( Yeong-su Park ),( Ho-jin Sung ),( Young-sik Yoon ),( Sung-bang Nam ),( Jae-hoi Gu ),( Jang-kun Lee ),( Il-byoung Choi ),( Jong Hyeog Oh ),( Dong-hyun Song ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-

In the gasification process, the composition of the syngas and its heating value are influenced by the gasifying agents. The gasifying agent can be air, oxygen, oxygen enriched air or steam. A preliminary study on oxygen-enriched gasification of fluff solid refuse fuel(SRF) was carried out in a bench-scale downdraft type fixed bed reactor. The purpose of this study is bring into focus the influence of the oxygen concentration in the gasifying agent on the gasification performance such as syngas heating value, carbon conversion and cold gas efficiency by the bench-scale fixed bed reactor.

Hydrogen Production from Methane under an Oxygen-enriched Conditions Using Compression Ignition Engine

Young-Nam Chun,Moon-Jung Youn,Sun-Il Kim 한국공업화학회 2007 Journal of Industrial and Engineering Chemistry Vol.13 No.7

This study on methane reforming suggests a new method using partial oxidation compression ignition reformer where the concept of super-adiabatic combustion is applied. In this research, optimum condition for producing hydrogen from methane, which is the main component of biogas, using a compression ignition reformer, is studied as a basic approach for producing synthetic gas from biogas. For compression ignition reformer using partial oxidation reaction, an unmodified compressed ignition internal combustion engine is used. The experiment is carried out using enriched oxygen by adding oxygen, which is oxidant, to expand the limit of inflammability range so that the engine could be operated even at the fuel -rich. The oxygen/fuel ratio (oxygen enrichment rate), total flow rate and intake preheating temperature were used as experiment variables.When oxygen/fuel ratio (oxygen enrichment rate: 77.2 %) is 1.24, total flow rate is 208.4 L/min and intake preheating temperature is 400 oC, the maximum hydrogen concentration obtained was 29.22, 26.93 and 23.53 % respectively.

EFFECTS OF HYBRID REBURNING/SNCR STRATEGY ON NOX/CO REDUCTION AND THERMAL CHARACTERISTICS IN OXYGEN-ENRICHED LPG FLAME

Lee, Chang Yeop,Baek, Seung Wook Taylor Francis 2007 Combustion science and technology Vol.179 No.8

<P> From the view of the environmental protection against the usage of fossil fuels, a great amount of effort has been exerted to find an effective method that is not only for pollutant reduction, but also for higher thermal efficiency. In order to enhance combustion efficiency, oxygen-enriched combustion is used by increasing the oxygen ratio in the oxidizer. However, since the flame temperature increases, NOx formation in the furnace seriously increases for low oxygen enrichment ratio. In this case reburning is a useful technology for reducing nitric oxide through injection of a secondary hydrocarbon fuel. In this article, an experimental study has been conducted to evaluate the hybrid effects of reburning and selective non-catalytic reaction (SNCR) on NOx/CO formation and also to examine heat transfer characteristics in an oxygen-enriched LPG flame. Experiments were performed in flames stabilized by a co-flow swirl burner, which was mounted at the bottom of the furnace. Tests were conducted using LPG gas as the reburn fuel as well as the main fuel. The effects of reburn fuel fraction and injection location of the reburn fuel as well as SNCR agent were studied. The paper reports data on flue gas emissions, temperature distribution in the furnace and various heat fluxes at the wall for a wide range of experimental conditions. At steady state, the total heat flux from the flame to the wall of the furnace has been measured using a heat flux sensor. Temperature distribution and emission formation in the furnace have also been measured and compared. Overall temperature in the furnace, heat fluxes to the wall and NOx generation were observed to increase with low level oxygen-enriched combustion, but due to its hybrid effects of reburning and SNCR, NOx and CO concentrations in the exhaust have decreased considerably</P>

INVESTIGATION OF RUNNING BEHAVIORS OF AN LPG SI ENGINE WITH OXYGEN-ENRICHED AIR DURING START/WARM-UP AND HOT IDLING

Xiao, G.,Qiao, X.,Li, G.,Huang, Z.,Li, L. The Korean Society of Automotive Engineers 2007 International journal of automotive technology Vol.8 No.4

This paper experimentally investigates the effects of oxygen-enriched air (OEA) on the running behaviors of an LPG SI engine during both start/warm-up (SW) and hot idling (HI) stages. The experiments were performed on an air-cooled, single-cylinder, 4-stroke, LPG SI engine with an electronic fuel injection system and an electrically-heated oxygen sensor. OEA containing 23% and 25% oxygen (by volume) was supplied for the experiments. The throttle position was fixed at that of idle condition. A fueling strategy was used as following: the fuel injection pulse width (FIPW) in the first cycle of injection was set 5.05 ms, and 2.6 ms in the subsequent cycles till the achieving of closed-loop control. In closed-loop mode, the FIPW was adjusted by the ECU in terms of the oxygen sensor feedback. Instantaneous engine speed, cylinder pressure, engine-out time-resolved HC, CO and NOx emissions and excess air coefficient (EAC) were measured and compared to the intake air baseline (ambient air, 21% oxygen). The results show that during SW stage, with the increase in the oxygen concentration in the intake air, the EAC of the mixture is much closer to the stoichiometric one and more oxygen is made available for oxidation, which results in evidently-improved combustion. The ignition in the first firing cycle starts earlier and peak pressure and maximum heat release rate both notably increase. The maximum engine speed is elevated and HC and CO emissions are reduced considerably. The percent reductions in HC emissions are about 48% and 68% in CO emissions about 52% and 78%; with 23% and 25% OEA, respectively, compared to ambient air. During HI stage, with OEA, the fuel amount per cycle increases due to closed-loop control, the engine speed rises, and speed stability is improved. The HC emissions notably decrease: about 60% and 80% with 23% and 25% OEA, respectively, compared to ambient air. The CO emissions remain at the same low level as with ambient air. During both SW and HI stages, intake air oxygen enrichment causes the delay of spark timing and the increased NOx emissions.

메탄-불소계 화합물의 예혼합화염 구조에서 산소 부화의 효과

이기용(Ki Yong Lee) 한국연소학회 2011 KOSCOSYMPOSIUM논문집 Vol.- No.42

Numerical simulations of freely propagating premixed flames burning mixtures of methane as fuel and trifluoromethane as an inhibitor were performed at atmospheric pressure in order to investigate the influence of trifluoromethane on CH₄/O₂/N₂ flames under the condition of the oxygen-enrichment. The calculated flame speeds were compared with those obtained from the experiments for flames at the oxygen-enrichment of 0.21, the results of which were in excellent agreement. Trifluouromethane significantly contributed toward the reduction of flame speed, the magnitude of which was larger by the physical effect than by the chemical effect. More trifluoromethane could be added and consumed on oxygen-enriched CH₄/O₂/N₂ flames. CHF₃ was decomposed primarily via CF₃→CF₂→CF→CF:O→CO and CHF₃+M →CF₂+HF+M had an important role in oxygen-enhanced flames. As an inhibitor was added on oxygen-enriched flames, the position of the maximum concentration of active radicals was shifted to the relatively low temperature range and the net rate of OH became higher than that of H.

저열량 합성가스의 산소부화 연소기술

조한창(Han Chang CHO),홍정구(Jung Goo HONG),조길원(Kil Won CHO),김기홍(Ki Hong KIM) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.38

A study was carried out in a bench-scale test furnace to investigate the flame stabilization and NOx emission in the burner used at hot rolling mill with oxygen-enriched air and combined gases generated in steel works. To do this, a bench scale test furnace is made and the test burners of 1000M㎈/h are designed. From the tests of NOx emission, it is confirmed that low calorific combined gases of 1500㎉/N㎥ can could be used with over 45% oxygen-composed air, but mix gas of 2800㎉/N㎥ must not be over 40% oxygen-composed air. In low calorific combined gases of 1500㎉/N㎥, the control of flame liftoff should be considered for the design of the burner.

산소부화 LPG 화염에서 혼합형 재연소 방법에 의한 NOx 저감 효과

이창엽(Chang Yeop Lee),백승욱(Seung Wook Baek) 한국연소학회 2007 한국연소학회지 Vol.12 No.4

In order to enhance combustion efficiency, oxygen-enriched combustion is used by increasing the oxygen ratio in the oxidizer. However, since the flame temperature increases, NOx formation in the furnace seriously increases for low oxygen enrichment ratio. In this case, reburning is a useful technology for reducing nitric oxide. In this research, experimental studies have been conducted to evaluate the hybrid effects of reburning/selective non-catalytic reaction (SNCR) and reburning/air staging on NOx formation and also to examine heat transfer characteristics in various oxygen-enriched LPG flames. Experiments were performed in flames stabilized by a co-flow swirl burner, which were mounted at the bottom of the furnace. Tests were conducted using LPG gas as main fuel and also as reburn fuel. The paper reported data on flue gas emissions, temperature distribution in furnace and various heat fluxes at the wall for a wide range of experimental conditions. Overall temperature in the furnace, heat fluxes to the wall and NOx generation were observed to increase by low level oxygen-enriched combustion, but due to its hybrid effects of reburning, SNCR and Air staging, NOx concentration in the exhaust have decreased considerably.

대향류 화염에서 CO₂ 재순환 산소부화연소의 NO 배출 특성

박준성(June Sung Park),박정(Jeong Park),조한창(Han Chang Cho) 한국연소학회 2007 한국연소학회지 Vol.12 No.1

Numerical study is conducted to grasp the flame structure and NO emissions for a wide range of oxy-fuel combustion (covering from air blown combustion to pure oxygen combustion) and for various mole fractions of recirculated CO₂ in CH₄-O₂/N₂/CO₂ counterflow diffusion flames. Special concern is given to the difference of the flame structure and NO emissions between air blown combustion and oxy-fuel combustion w/o recirculated CO₂ and is also focused on chemical effects of recirculated CO₂. Air blown combustion and oxy-fuel combustion w/o recirculated CO₂ are shown to be considerably different in the flame structure and NO emissions. Modified fuel oxidation reaction pathways in oxygen-enriched combustion are provided in detail compared to those in air blown combustion w/o recirculated CO₂. The formation and destruction of NO through Fenimore and thermal mechanisms are also compared for air blown combustion and oxyegn-enriched combustion w/o recirculated CO₂, and the role of the recirculated CO₂ and its chemical effects are discussed. Importantly contributing reaction steps to the formation and destruction of NO are also estimated in oxygen-enriched combustion in comparison to air blown combustion ..

메탄-불소계 화합물의 예혼합화염 구조에서 산소 부화의 효과

이기용(Ki Yong Lee) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.8

산소부화 조건의 CH₄/O₂/N₂ 화염에서 트리플루오르메탄의 영향을 조사하기 위해 1기압에서 자유롭게 전파하는 예혼합 화염에 대한 수치해석을 수행하였다. 트리플루오르메탄은 화염속도 감소에 기여하며, 감소의 크기는 화학적 효과보다 물리적 효과에 의해 더 크다. 트리플루오르메탄은 산소부화된 CH₄/O₂/N₂ 화염에서 더 많이 첨가되고 소비될 수 있다. 트리플루오르메탄은 주로 CF₃→CF₂→CF→CF:O→CO을 통해 분해되고, 산소부화 화염에서 CHF₃+M→CF₂+HF+M이 중요한 역할을 한다. 억제제가 산소 부화 화염에 첨가함에 따라 활성기 최대 농도의 위치는 상대적으로 낮은 온도로 이동하고, OH의 순생성률은 H의 순생성률보다 높다. We performed numerical simulations of freely propagating premixed flames at atmospheric pressure to investigate the influence of trifluoromethane on CH₄/O₂/N₂ flames under oxygen enrichment. Trifluoromethane significantly contributed toward a reduction in flame speed, the magnitude of which was larger in terms of the physical effect than the chemical effect. More trifluoromethane could be added and consumed on oxygen-enriched CH4/O2/N2 flames. CHF₃ was decomposed primarily via CF₃→CF₂→CF→CF:O→CO and CHF₃+M→CF₂+HF+M played an important role in oxygen-enhanced flames. When an inhibitor was added to oxygen-enriched flames, the position of the maximum concentration of active radicals was shifted to a relatively low temperature range, and the net rate of OH became higher than that of H.