Burner Outlet Research Articles

Experimental investigation of the effect of air/fuel ratio change on JP8 swirl flame characteristics with image processing methods

In this study, the stable combustion ranges and emission values of JP8 fuel, which is used in military aviation, were tested and optimum conditions were determined. The AFR (Air/Fuel Ratio) of the JP8 flame was increased experimentally at constant thermal power in a gas turbine combustion chamber. In the study, AFR were tested as 30/1, 33/1, 36/1, 39/1 and 42/1. A generator with 0.4 swirl number is placed at the burner outlet. Under these conditions, the effect of external acoustic enforcement frequencies on dynamic instabilities at different AFR was investigated. Flame length and thickness data were extracted from the images obtained from the image processing technique. The effect of AFR change on the combustion chamber temperature was examined and pollutant emissions were measured. The results showed that the most stable flame appeared in AFR 33/1 case at 155 and 300 Hz resonance frequencies under acoustic enforcements. Additionally, when the AFR was increased to 42/1, flame instability increased at all frequency values. Moreover, it has been determined that the most optimum mixture in terms of combustion chamber exit temperature and CO emissions is AFR 33/1. There was an increase in NOX emissions by up to 39/1 with the increase in AFR.

Combustion in a chamber furnace with a tangentially swirling vortex

Relevance. The need to analyze the furnace processes in boiler units with vertical vortex when arranging pulverized coal combustion with the enhancement of environmental parameters through the installation of tertiary blast nozzles. Despite the carbon-free policy in modern power engineering coal remains one of the main sources of energy, so the reconstruction of boiler units in order to reduce harmful emissions is very relevant. Aim. To study aerodynamics and combustion processes of pulverized coal fuel in the furnace chamber of a boiler unit with a tangential arrangement of burner devices using a combustion scheme with tertiary air blowing. Methods. The Eulerian–Lagrangian approach was applied to numerical study of flow characteristics, heat transfer and combustion in a furnace with a tangential burner arrangement. Also, k-ε model of gas turbulence, particle-turbulence interaction, diffusion model of particle dispersion, P-1 radiation modeling method and pulverized coal particle combustion model based on global particle kinetics and experimental data were used for numerical calculations. Results. Based on numerical calculations and analysis, the dependences of combustion product concentrations, temperature, hydrodynamics at combustion of Kuznetsky coal grade D in the furnace chamber with tangential arrangement of burners for brown coal, as well as at installation of tertiary blast nozzles have been obtained. Insufficient redistribution of air between burners and tertiary nozzles is revealed, as for maintenance of stable twist of vertical vortex and accordingly presence of high values of velocities at the outlet of burner devices it is not possible to increase the portion of tertiary air without reconstruction of burners. It is also established that the volume of the furnace chamber below the burners is poorly involved in heat exchange.

Numerical and Experimental Study on Preheating Burner Characteristics for Peak Shaving

With the proportion of renewable energy power in the electricity market gradually increasing, coal-fired power is transforming from primary to basic power, with it providing peak and frequency shaving. However, most current methods for peaking below 50% load have been applied industrially, sacrificing the efficiency of the unit. This is not in line with the goals of energy conservation and emission reduction. Therefore, this study proposes a new preheating-based peaking method. This study experimentally and simulatively explores the flow characteristics, pyrolysis gas law, and NOx emission characteristics of a preheating burner at 40–100% load. The results show that the burner has a significant preheating effect, producing high-temperature char and large amounts of pyrolysis gas. As the load decreases, the burner exit temperature increases, whereas the airflow stiffness decreases. There is little variation in the pyrolysis gas concentration between 40% and 100% loads. The NOx concentration at the burner outlet increases and the reduction efficiency decreases with decreasing load. At 40% load, NOx emissions are 91.53 mg/Nm3 and the reduction efficiency reaches 95.9%. Therefore, preheating is an economical, stable, and low-NOx-emission-peaking method. This study provides theoretical guidance for the application of preheating burners for the 40–100% load peaking of coal-fired units.

Study on mixing performance of atmospheric entrained flow gasification burner using fine ash as feedstock

A burner structure suitable for atmospheric entrained-flow gasifiers using fine ash as feedstock was proposed. The study investigates the impact of the burner structure on the mixing characteristics through 0.75:1 (geometry reduction) single-phase airflow experiments. Additionally, numerical simulations were conducted to study of the gasification process of fine ash in a 10,000 Nm3/h atmospheric entrained flow gasifier. The results indicate that a larger residual temperature near the burner outlet was observed when the diameter of the burner's gasification agents channel was 10 mm or 15 mm, approximately 0.7–0.8. Additionally, the mixing degree of the two airflows at the burner outlet was high, and the distance required for complete mixing was short. When the diameter of the gasification agent channel was 15 mm, the mixed syngas flow velocity was appropriate. This resulted in a maximum temperature of 2500 °C, an 80 % carbon conversion rate, and an outlet effective syngas (CO + H2) concentration of 62 %.

Influence of secondary air blade angle and oxygen-rich combustion characteristics of an improved Babcock swirl burner

Innovations in research methods and stable combustion technologies were urgent to enhance flexibility in faulty coal-fired boiler. Focusing boiler start-stop processes was vital for effective peak shaving in power plants. The integration of enriched oxygen stable combustion with swirling techniques showed promise in improving low-load performance. In the cold single–phase experiment, the influence of secondary blade angle on the flow field of an improved Babcock burner was observed. Industrial experiments were conducted on a 700 MW boiler, exclusively implementing the improved burners in the lower layer of the boiler front wall. Stable annular recirculation zones were observed at the burner outlet with blade angles of 30°, 45°, 60°, and 75° for the secondary air. Increasing the blade angle expanded the recirculation zone length and decreased the gas net flow ratio. The angle, between 45° and 60°, facilitated air mixing and protected against outlet slagging and high-temperature corrosion. During cold start–up process of the boiler, supplying 0 kg·s−1 of pure oxygen to a single improved burner increased the flue gas temperature by about 50 °C within 0.4 m of the primary air duct outlet. Increasing the oxygen flow rate to 0.2456 kg·s−1 steadily raised the flue gas temperature at 405 MW. The gas temperature in the burner central region was generally lower than the secondary air zone, resulting in a longer ignition distance for the pulverized coal. Higher oxygen levels intensified the heating rate and reduced the ignition distance in the central region.

Enhanced ammonia combustion by partial pre-cracking strategy in a gas turbine model combustor: Flame macrostructures, lean blowout characteristics and exhaust emissions

Cofiring with hydrogen presents a reasonable approach to achieve enhanced ammonia (NH3) combustion without introducing an extra carbon footprint. A promising strategy for NH3/H2 cofiring in gas turbines involves on-site partial pre-cracking of NH3 and burns of NH3/H2/N2 mixtures, eliminating additional hydrogen transportation and storage. This work investigates the effects of the pre-cracking ratio (γ) on flame macrostructures, lean blowout characteristics and exhaust emissions of the partially pre-cracked NH3 flames in a single-swirl gas turbine model combustor. Flow and flame macrostructures were captured using particle image velocimetry (PIV) and OH planar laser-induced fluorescence (OH-PLIF) measurements. Lean blowout limits (ϕLBO) were assessed under varying γ, and emissions at the burner outlet were measured using a Fourier transform infrared spectroscopic (FTIR) gas analyzer. Results show that as γ increases, the flame exhibits a shortened height, strengthened OH fluorescence, amplified core jet velocities and significantly reduced ϕLBO, indicating an effective enhancement of NH3 combustion by partial pre-cracking strategy. Nevertheless, NO and NO2 emissions exhibit a substantial increase with larger γ. Opposite trends of NO and NH3 emissions versus equivalence ratio (ϕ) suggest a trade-off between NO and NH3 emissions, with relatively low NO/NH3 window appearing under slightly-rich (ϕ = 1.0–1.1) conditions. Low NO emissions are also noted under ultra-lean conditions (ϕ = 0.4–0.5) with the penalty of high NH3 and N2O emissions, making it an unacceptable trade-off. Furthermore, the effect of N2 separation from the partially pre-cracked NH3 mixtures was evaluated at γ = 0.4. The results show deteriorating effects on NOx emissions, resulting in 13 % and 21 % increases in peak NO and NO2 emissions, respectively, which implies more feasibility to burn the partially pre-cracked NH3 in a direct manner rather than N2 separation.

Laser interferometric detection of heat release rate perturbation field of acoustically perturbed laminar premixed flames

Laser interferometry, which was originally used to measure density perturbation, has been previously used to determine the heat release rate perturbation, which is a key factor in the analysis of combustion instability. However, its spatial accuracy is still unsatisfied. In the present work, an improved fringe Fourier analysis method is proposed to process the results obtained from the laser interferometry measurement, aiming to accurately determine the spatial distribution of flame heat release rate perturbation. The measurement of heat release rate perturbation was performed on a acoustic perturbed laminar premixed flame, with the burner outlet diameter of 8 mm. Interference patterns generated by two laser beams with a diameter of 70 mm were recorded at a frame rate of 6000 Hz. A spatial dependent fringe processing method, referred as the improved fringe Fourier analysis, was developed to demodulate the interference phase from the fringe patterns. The proper orthogonal decomposition analysis was performed on these results to analyze the component of interference signals. Validation of the present technique was conducted by comparing the heat release rate perturbation field resulting from the laser interferometric technique to those from the CH* chemiluminescence from the flame. Comparisons were performed both for the global and local values, and the low-frequency natural oscillation effects were analyzed. Finally, a refraction correction method based on background-oriented Schlieren is proposed to compensate the beam deflection caused by flame.

Numerical Simulation Study of Hydrogen Blending Combustion in Swirl Pulverized Coal Burner

Hydrogen blending of pulverized coal in boilers is a promising technology. However, there are few studies on hydrogen blending in coal-fired boilers. In order to reduce CO2 emissions from coal-fired boilers, this study investigates the co-combustion of pulverized coal and hydrogen in a swirl pulverized coal burner by numerical simulation. Itis shown that the burnout rate of fuel is 5.08% higher than that of non-hydrogen blended coal when the percentage of hydrogen blended is 5%. The water vapor generated by hydrogen blending not only leads to the formation of a low-temperature zone near the burner outlet; it also results in a prolonged burnout time of moist pulverized coal and a high-temperature zone near the furnace outlet. The greater the amount of hydrogen for blending, the higher the water produced. When 1–3% hydrogen is blended, the water vapor in the furnace reacts with the carbon to produce a large amount of CO. When the amount of hydrogen added to the furnace is more than 3%, the water content in the furnace rises, resulting in a lower temperature at the burner outlet and a decrease in the amount of CO produced. When 1–3% hydrogen is blended, the CO2 emission rises. The CO2 emission decreased by 1.49% for 5% hydrogen blending compared to non-hydrogen blending and by 3.22% compared to 1% hydrogen blending.

Effect of the Cross-Section of a Porous Burner on the Combustion Stability Limit of Premixed Oxy-Methane Flames.

This study presents the idea of using a porous media burner to improve the oxy-methane combustion reaction rate and broaden the stability limit. Numerical studies on the premixed combustion of CH4/O2/CO2 in a two-layer porous medium burner using a two-dimensional symmetrical volume-average model with the skeleton mechanism based on OpenFOAM. The combustion characteristics of burners with variable cross-sectional (VC) and straight cylindrical (SC) structures were compared, including stable range, temperature field, thermal cycle efficiency, and CO emissions. It is confirmed that the cross-sectional structure is effective for broadening the stable range, and the broadening rate is more than 4 times. As more heat is lost from the outlet due to the increased cross-section, the solid-phase temperature of VC is lower than that of SC. As a result, the flame temperature of VC will be about 200 K lower than that of SC under the condition of insulated walls. It also leads to a reduction of about 2% in thermal cycle efficiency compared with SC. Meanwhile, it is shown that the VC structure slightly increases CO emissions at low thermal power but is smaller than that of SC at high power. When the wall heat loss of the burner is considered, the VC structure is still effective for improving the stable range. In addition, the VC structure slightly affects flame tilt and temperature uniformity at the burner outlet when the thermal power is large. It is confirmed that the VC structure is effective for increasing the power adjustment range and reducing pollutant emissions at high power.

Statistical approach and numerical analysis of turbulent diffusion flame of CH4/H2 mixture

ABSTRACT In the present study, the methane/air turbulent diffusion flame enrichment by hydrogen, has been numerically investigated using a statistical approach. The countercurrent flame has been analyzed in the plane of the mixture fraction using the flame let approach. The chemical kinetics have been represented by the GRI Mech-3.0 mechanism, whereas the simulations have been performed with the PDF approach, and the modified k-ε turbulence model. Furthermore, the effect of the hydrogen addition to CH4/H2 melange with an amount of 0% to 20% was investigated; the flamelet model was first used to create a library of chemical characteristics of the laminar flame structure in the form as a mixture fraction Z-function. Next, we coupled the turbulent field to obtain the turbulent modeled flame structure with the modified k-ε model. The numerical results revealed that using the flamelet model allows an improvement of the mixture quality while adding hydrogen, whereas the maximum consumption zone occurs near the burner outlet, and the combustion temperature increases under the effect of hydrogen doping which reached 1884K, in which the NO mass fraction follows the same temperature evolutions.

N2 and Ar dilution on the premixed biogas jet flame under external acoustic enforcement

In this study, combustion instabilities and flue gas emission changes under different dilutions of N2 (nitrogen) and Ar (argon) of a promising biogas mixture (70% CH4 - 30% CO2) in the fight against greenhouse gas emissions were investigated. In the experiments, additions were made from 0% to 50% at intervals of 10% for both gases. In order to detect the instability of the flame, external acoustic enforcements at different frequencies was applied through the speakers placed in the combustion chamber arms. The dynamic pressure fluctuation values were recorded. The results showed that low dilution ratios were effective in reducing flame instability for both inert gases. However, as the dilution ratio increased, the fuel/air mixture became leaner and blowoff occurred. In the case of comparing two different gases, it has been observed that the effect of argon gas on reducing dynamic pressure fluctuation is higher. Burner outlet temperature and brightness values of the flame decreased in both Ar and N2 dilution. CO and NOx emissions increased with increasing diluent volume for all dilution conditions. When the emissions of the two diluent gases are compared, the CO emission, which was 3134 ppm in the undiluted condition, increased up to 4949 ppm in 50% Ar dilution, while it increased to 4521 ppm in 50% N2 dilution.

Study on CO2* chemiluminescence of CH4/O2 co-flow diffusion flame based on the chemical kinetic mechanism

Chemiluminescence of CO2* is suitable for characterizing flame properties such as flame structure, equivalence ratio and heat release rate. However, experimental studies and numerical simulations of CO2* are not yet complete. In this work, the two-dimensional distributions of CO2* chemiluminescence were obtained by a high-resolution CCD camera. Numerical simulation results of CO2* were performed based on the detailed reaction kinetics mechanism of CO2* and were in good agreement with that of experiments. The differences of CO2* reactions at different axial positions were studied. The main CO2* formation reaction R2(CH + O2 = CO2*+H) at the burner outlet and R1(O + CO + M = CO2*+M) at the core reaction zone were determined. On the fuel side, the R1 reaction rate was mainly affected by temperature. On the oxidizer side, the R1 reaction rate was affected by temperature and reactant mole fraction. The main quenching reaction was R5(CO2*+H2O = CO2 + H2O). The oxygen-fuel equivalence ratio changed the reaction rate of formation and quenching reactions mainly by affecting temperature and reactant mole fraction.

Study on combustion characteristics of fully premixed water-cooled biogas burner

Biogas is a renewable gas produced by the fermentation of biomass and is an environmentally friendly alternative to traditional fossil fuels. To overcome the problems of traditional biogas burner, such as unstable combustion, easy flameout and backfire, and low thermal intensity, a new water-cooled biogas burner based on fully premixed combustion technology was designed and developed. Then, numerical simulations and experimental investigations were conducted to explore the effects of CO2 content, excess air coefficient, heat load, and cooling water temperature on the combustion characteristics of the burner. The results revealed that the designed burner exhibited good adaptability to simulated biogas with methane concentrations ranging from 55 % to 80 %. Increasing CO2 content resulted in decreased combustion temperatures and reduced NOx and CO emissions concentration at the burner outlet. In addition, reducing the excess air coefficient enhanced the combustion heat intensity and reduced combustion heat loss. Nevertheless, excessively low excess air coefficients yielded elevated levels of NOx and CO in the flue gas. The results showed that the designed burner demonstrated stable operation at a minimum heat load of 35 %, exhibited a favorable load regulation ratio, and had low emissions. It is a promising solution for utilizing biogas as a clean and sustainable energy source.

Research and Development of an Industrial Denitration-Used Burner with Multiple Ejectors via Computational Fluid Dynamics Analysis

Nowadays, since the air pollution problem is becoming global and denitrification is efficient to control nitrogen oxides, research and development of burners with low pollutant emissions in industries are urgent and necessary due to the increasingly severe environmental requirements. Based on the advanced CFD (computational fluid dynamics) numerical analysis technique, this work focuses on developing an industrial denitration-used burner, aiming to decrease the emission of nitrogen oxides. A burner with multiple ejectors is proposed, and the gas premixing and combustion process in the burner are systematically studied. Firstly, for the ejector, the well-known orthogonal experiment method is adopted to reveal the premixing performance under different structural parameters. Results show that the angle and number of swirl blades have significant effects on the CO mixing uniformity. The CO mixing uniformity first decreases and then increases with thr rising swirl blade angle, and it enhances with more swirl blades. Through comparison, a preferred ejector is determined with optimal structure parameters including the nozzle diameter of 75 mm, the ejector suction chamber diameter of 290 mm, the blade swirl angle of 45∘, and the swirl blade number 16. And then, the burners installed with the confirmed ejector and two types of flues, i.e., a cylindrical and a rectangular one, are simulated and compared. The effects of ejector arrangements on the temperature distributions at the burner outlet are analyzed qualitatively and quantitatively. It is found that the temperature variances at the outlets of R2 and C1 are the smallest, respectively, 13.12 and 23.69, representing the optimal temperature uniformity under each type. Finally, the burner of the R2 arrangement is verified with a satisfied premixing performance and combustion temperature uniformity, meeting the denitration demands in the industry.

Experimental Investigation of a Self-Sustained Liquid Fuel Burner Using Inert Porous Media

A self-sustained porous burner without a sprayed atomizer was built for diesel oil. It consisted of metal fiber felt as an evaporator upstream and ceramic foam as an emitter downstream. The liquid fuel underwent film boiling in the porous evaporator and was rapidly evaporated by the heat recirculated from the porous emitter to the porous evaporator through intense irradiative heat flux. The effect of the porous structure and its installation location on the performance of the porous burner was investigated. The results indicated that the evaporation and combustion of liquid fuel could be prompted by the radiation of porous media. The position of the flame moved downstream, and the flame temperature decreased when the distance between the metal fiber felt and the ceramic foam was increased. The lowest NOx concentration was obtained when the distance between the foam and the metal fiber felt was 90 mm. When the diameter of the central hole of the ceramic foam was increased, the position of the flame moved towards the burner outlet, and the flame temperature and NOx emission declined. The flame temperature of the divergent configuration as emitter was higher than that of the convergent configuration, and the flame temperature of the C–D configuration was higher than that of the D–C configuration. Different ceramic foam structures had a significant effect on the temperature and emission in the combustion chamber, which showed that the evaporation and radiation performance of inert porous media burners with different structures is quite different.

Influence of Central Air on Flow and Combustion Characteristics and Low-Load Stabilization Performance of a Babcock Burner

On a cold single-phase test stand, the effect of central air on the exit flow field of Babcock, Germany, burner was investigated. Industrial measurements were taken for a 700 MW wall-fired pulverized-coal utility boiler with above burners. Gas temperature, gas composition and concentration in the burner area were measured at 444 MW, 522 MW and 645 MW loads, respectively. Only when the central air mass flow was zero did a center reflux zone exist in the burner outlet area. The steady combustion of faulty coal was aided by early mixing of primary and secondary air, which was made possible by the decreased central air mass flow. At all different loads, the pulverized coal in center region took a long distance to ignite. The temperature in center steadily dropped as central air mass flow decreased, while the temperature in secondary air region gradually rose. Within 1.5 m from the primary air duct outlet, the highest CO concentration was 25 ppm and the highest O2 concentration was close to 21% under all loads. The gas concentration near sidewall was more influenced by load. With all valves opening of burner center air at 30%, the boiler was able to operate safely and stably without oil at a load of 262 MW. The furnace chamber temperature in burner area reached 1056.1 °C.

Hydrogen concentration effects on a swirl-stabilized non-premixed burner using ammonia

In the present paper, it was aimed to consume pure NH3 by using an existing non-premixed burner with H2 blending strategy, and to examine the temperature and NO emission profiles emerged in a model combustor for NH3/H2 and pure NH3 fuel compositions. The Mixture Fraction/PDF combustion model with a reduced reaction mechanism was used for the numerical modelling. During the experimental studies, a stable NH3/air flame was able to achieve by introducing H2 into the burner since NH3/air mixture has a low reactivity and needs a high ignition energy. However, any flashback or lift-off tendency was not observed for NH3/H2/air or NH3/air flames. The numerical and experimental results showed that H2 addition into NH3/air mixture provided higher temperature values both in the flame region and in the entire combustor. As the concentration of H2 in the mixture was raised, the flame approached towards to the burner outlet with increment effect in burning velocity. However, H2 addition into NH3/air mixture led to more NO emissions formation in the combustor. This can be attributed with that H2 addition promoted both thermal and fuel-NO mechanisms because H2 addition induced to increase the decomposition rate of NH3 and flame temperature of NH3/air mixture. This finding was validated with the prediction of the concentrations of O and HNO radicals for all fuel compositions. Consequently, H2 introduction contributed to the flame stability of NH3/air mixture even if more NO formation was observed.

Low-NOx study of a 600 MW tangentially fired boiler based on pulverized coal preheating method

Boiler emissions are the primary sources of atmospheric nitrogen oxide (NOx) emissions. Exceeding the NOx emission limit can shut down the boiler, causing financial losses. Herein, a new preheated combustion method is proposed to prevent coal-fired boilers from exceeding the NOx emission limit at low loads. This is a simulation study of internal combustion burners and a 600 MW tangentially fired boiler using a pulverized coal preheating method that explores syngas production patterns after pulverized coal is preheated, the effects of flow characteristics, and variations in NOx and unburned carbon content under different preheating ratios. Our results indicated that the internal combustion burner had a stable preheating effect. The volume fractions of CH4, CO, and H2 at the burner outlet were 0.95%, 12.7%, and 0.8%, respectively. The fuel nitrogen precipitated during the preheating process was converted into N2. High-temperature char and syngas entered the furnace chamber and were mixed with air to accelerate combustion, which enhanced the jet flow intensity and improved the combustion stability at 50% load. The top burner exhibited a more significant nitrogen reduction than the bottom burner. The NO reduction from retrofitting Layers D and E accounted for 53% after retrofitting all five layers. When the preheating ratio was increased from 0 to 100%, NOx concentration was reduced by 63.6% at 6% O2, while unburned carbon content was reduced by 41%, which improved combustion efficiency. By discussing the advantages of internal combustion burners for retrofitting a 600 MW tangentially fired boiler, this study provides theoretical guidance for the application of preheating methods in peaking conditions.

Experimental Study on Combustion Optimization of Supercritical 600MW Quadrangle Tangential Boiler

Given the problems existing in the operation of supercritical 600MW boiler, such as spiral pipe water cooling wall outlet, superheater and reheater wall surface overtemperature easily, the superheater and reheater cooling water amount are too large under high load, and the low load cooling water amount is too small to meet the need of cold reheater heating, the boiler combustion optimization and adjustment are carried out. Through the boiler pulverized coal fineness, air distribution characteristics, swinging Angle of burner and furnace outlet is optimized, such as oxygen level superheater heating surface overtemperature problems are solved, such as the reheater desuperheating water flow under different load can meet the needs of heat supply, at the same time, it also improves the boiler efficiency, effectively improve the safety and economy of the unit.

Effect of oxygen enrichment of Biogas-Hydrogen mixtures in a premixed combustor on the combustion instability and emissions

The effect of enrichment of a low calorific (50 % CH4-50 % CO2) biogas mixture with hydrogen and oxygen has been investigated on combustion stability and exhaust emissions in a premixed burner. The thermal power was kept constant at 5 kW, the equivalence ratio of 0.8, and a swirl generator (1) was placed at the burner outlet. Initially, hydrogen (H2) was added to the biogas at intervals of 10 % up to 40 % by volume. The addition of hydrogen to the biogas increased the heating value of the mixture and reduced the instabilities. It has been determined that biogas/hydrogen mixtures containing 20 % and 30 % H2 showed the lowest combustion instability and pollutant emissions. It has been observed that with the addition of 30 % hydrogen to the biogas, the CO emission value, which was 5532 ppm, decreased to 130 ppm. Also, 23 % and 25 % O2 enrichment were applied to fuel mixtures. It was observed that combustion instabilities increased with oxygen enrichment in both fuel mixtures and flashbacks occurred under acoustic perturbation. It has been determined that the mixture containing 20 % H2 as the flame, which has the lowest emission and is resistant to acoustic perturbation, is burned at the 23 % O2 ratio by volume.