scholarly journals Numerical Investigation on the Flow, Combustion and NO Emission Characteristics in a 10 MW Premixed Gas Burner

2015 ◽  
Vol 8 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Weibo Chen ◽  
Guixiong Liu
Keyword(s):  
Fluid Dynamics ◽  
Combustion Temperature ◽  
Flame Structure ◽  
Combustion Efficiency ◽  
Emission Characteristics ◽  
No Emission ◽  
Evaluation Indexes ◽  
Gas Burner ◽  
Burner Design ◽  
Secondary Air

The characteristics of the combustion temperature, flow velocity, CO distribution and NOx emissions of a 10 MW gas burner at different primary to secondary air ratios are numerically studied using computational fluid dynamics software Fluent. The results indicate that the primary to secondary air ratio in gas burner determines the combustion quality through influencing some parameters directly, such as the combustion efficiency, combustion intensity, profile and stability of flame as well as emission of NOx. Then two evaluation indexes of combustion quality are summarized after analyzing the flame structure and characteristics of the flow. The detailed results reported in this paper may provide a useful basis for NOx reduction and premixed gas burner design. Finally some proposals are given to choose the optimal primary to secondary air ratio for a gas burner.

Modeling and Experiment on Combustion Characteristics for Biomass Rotary Burner

2020 ◽  
Vol 04 ◽  
Author(s):  
Guohai Jia ◽  
Lijun Li ◽  
Li Dai ◽  
Zicheng Gao ◽  
Jiping Li
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Combustion Efficiency ◽  
Middle Part ◽  
Combustion Characteristics ◽  
Maximum Temperature ◽  
Excess Air ◽  
Element Simulation ◽  
Excess Air Coefficient ◽  
Secondary Air

Background: A biomass pellet rotary burner was chosen as the research object in order to study the influence of excess air coefficient on the combustion efficiency. The finite element simulation model of biomass rotary burner was established. Methods: The computational fluid dynamics software was applied to simulate the combustion characteristics of biomass rotary burner in steady condition and the effects of excess air ratio on pressure field, velocity field and temperature field was analyzed. Results: The results show that the flow velocity inside the burner gradually increases with the increase of inlet velocity and the maximum combustion temperature is also appeared in the middle part of the combustion chamber. Conclusion: When the excess air coefficient is 1.0 with the secondary air outlet velocity of 4.16 m/s, the maximum temperature of the rotary combustion chamber is 2730K with the secondary air outlet velocity of 6.66 m/s. When the excess air ratio is 1.6, the maximum temperature of the rotary combustion chamber is 2410K. When the air ratio is 2.4, the maximum temperature of the rotary combustion chamber is 2340K with the secondary air outlet velocity of 9.99 m/s. The best excess air coefficient is 1.0. The experimental value of combustion temperature of biomass rotary burner is in good agreement with the simulation results.

scholarly journals Numerical Study of the Structure and NO Emission Characteristics of N2- and CO2-Diluted Tubular Diffusion Flames

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1490
Author(s):  
Harshini Devathi ◽  
Carl A. Hall ◽  
Robert W. Pitz
Keyword(s):  
Diffusion Flames ◽  
Numerical Study ◽  
Reaction Pathway ◽  
Flame Structure ◽  
Reaction Rates ◽  
No Production ◽  
Emission Characteristics ◽  
No Emission ◽  
Nitrogen Radicals ◽  
Lower Temperature

The structure of methane/air tubular diffusion flames with 65 % fuel dilution by either CO2 or N2 is numerically investigated as a function of pressure. As pressure is increased, the reaction zone thickness reduces due to decrease in diffusivities with pressure. The flame with CO2-diluted fuel exhibits much lower nitrogen radicals (N, NH, HCN, NCO) and lower temperature than its N2-diluted counterpart. In addition to flame structure, NO emission characteristics are studied using analysis of reaction rates and quantitative reaction pathway diagrams (QRPDs). Four different routes, namely the thermal route, Fenimore prompt route, N2O route, and NNH route, are examined and it is observed that the Fenimore prompt route is the most dominant for both CO2- and N2-diuted cases at all values of pressure followed by NNH route, thermal route, and N2O route. This is due to low temperatures (below 1900 K) found in these highly diluted, stretched, and curved flames. Further, due to lower availability of N2 and nitrogen bearing radicals for the CO2-diluted cases, the reaction rates are orders of magnitude lower than their N2-diluted counterparts. This results in lower NO production for the CO2-diluted flame cases.

Oxygen Enriched and Oxyfuel Combustion - Promising Trends for Low Carbon Future

2011 ◽  
Vol 145 ◽  
pp. 11-15
Author(s):  
M. Tayyeb Javed ◽  
Bill Nimmo
Keyword(s):  
Flue Gas ◽  
Line Emission ◽  
Combustion Efficiency ◽  
Base Line ◽  
Exhaust Gas ◽  
Low Carbon ◽  
No Emission ◽  
Oxyfuel Combustion ◽  
Test Conditions ◽  
Secondary Air

The escalation of ambient CO2 concentration due excessive use of coal in power generation has put impetus on the development of technologies for utilization of vast and cheap resources available through out the world. Eco-scrub, Oxygen enriched and oxyfuel combustion are among the promising technologies guaranteeing the low carbon future. In our recent investigations, pulverized coal (Russian) was fired in a 20 kW down fired combustion rig under simulated exhaust gas recirculation. The effect of CO2 at burner inlet on the combustion efficiency, flue gas CO2 and NO emission was studied. The test conditions were essentially achieved by replacing the secondary air with a mixture of O2 and CO2 in different proportion. The test conditions do imitate the four key conditions for eco-scrub project. The basic theme under eco-scrub project is to use limited oxygen addition to reduce the volume of flue gas for processing, increase the efficiency of post combustion scrubbing due to higher CO2 levels and reduced the size and cost of post combustion capture. The exhaust gas CO2 was observed to increase linearly with increasing the CO2 at burner inlet. The flue gas concentration for 35% and 45% flue gas recycle was recorded to be 24% and 30% respectively. The NO emission was most of the time under the base line emission of 818 ppm. A maximum of 66% reduction was observed when the burner inlet CO2 was 45% and 21% O2. How ever an increase of 37% was seen when 80% of the secondary air was replaced with a 50%O2-50%CO2 mixture.

Effects of Over Fire Air on the Combustion and NOx Emission Characteristics of a 600 MW Opposed Swirling Fired Boiler

2012 ◽  
Vol 512-515 ◽  
pp. 2135-2142 ◽  
Author(s):  
Yu Peng Wu ◽  
Zhi Yong Wen ◽  
Yue Liang Shen ◽  
Qing Yan Fang ◽  
Cheng Zhang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Empirical Method ◽  
Nox Emission ◽  
Emission Characteristics ◽  
Cfd Model ◽  
Nitrogen Release ◽  
Computational Fluid Dynamics Cfd ◽  
Low Nox Emission

A computational fluid dynamics (CFD) model of a 600 MW opposed swirling coal-fired utility boiler has been established. The chemical percolation devolatilization (CPD) model, instead of an empirical method, has been adapted to predict the nitrogen release during the devolatilization. The current CFD model has been validated by comparing the simulated results with the experimental data obtained from the boiler for case study. The validated CFD model is then applied to study the effects of ratio of over fire air (OFA) on the combustion and nitrogen oxides (NOx) emission characteristics. It is found that, with increasing the ratio of OFA, the carbon content in fly ash increases linearly, and the NOx emission reduces largely. The OFA ratio of 30% is optimal for both high burnout of pulverized coal and low NOx emission. The present study provides helpful information for understanding and optimizing the combustion of the studied boiler

scholarly journals COMBUSTION PERFORMANCE OF SYNGAS FROM BIOMASS WASTE IN GAS BURNER SYSTEM/PRESTASI PEMBAKARAN SYNGAS DARI SISA BIOJISIM DALAM SISTEM PEMBAKAR GAS

2018 ◽  
Vol 80 (5) ◽  
Author(s):  
Mohd Oryza Mohd Mokhtar ◽  
Mohammad Nazri Mohd Ja’afar ◽  
Mustafa Yusoff ◽  
Mazlan Said ◽  
Muhammad Roslan Rahim ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Sulfur Dioxide ◽  
Nitrogen Oxide ◽  
Combustion Temperature ◽  
Fossil Fuel ◽  
Biomass Waste ◽  
Gas Combustion ◽  
Combustion Performance ◽  
Positive Effects ◽  
Gas Burner

Syngas from biomass residues is an alternative fuel to address the ever-increasing fossil fuel supply problem and the issue of releasing toxic gases from the fossil fuel burning process. Syngas is also a renewable fuel and features environmentally friendly fuel. This study was conducted to investigate the performance of the syngas produced from oil palm shells (PKS) using fluidized bed gasifier. In this study, the produced syngas was tested for its combustion performance from the aspect of gas combustion temperature and resulting emission concentrations such as nitrogen oxide (NOx), carbon monoxide (CO) and sulfur dioxide (SO2). The resulting syngas was studied at different ratio of air velocities to fuels. From the test, the ratio of velocity of air to fuel affects the gas combustion temperature and emission emission concentration. By increasing the air velocity to fuel ratio during the gasification process produces more positive effects primarily in improving the temperature of the gas burner combustion and reducing carbon monoxide (CO) emissions. However, the concentration of sulfur dioxide release (SO2) and nitrogen oxide (NOx) increase.

High Fidelity Modeling of the Acceleration of a Turboshaft Engine During a Restart

2018 ◽  
Author(s):  
Antoine Ferrand ◽  
Marc Bellenoue ◽  
Yves Bertin ◽  
Radu Cirligeanu ◽  
Patrick Marconi ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Combustion Efficiency ◽  
High Fidelity ◽  
Gas Generator ◽  
Idle Speed ◽  
Flight Mode ◽  
System States ◽  
Secondary Air ◽  
Turboshaft Engine ◽  
High Level

In order to decrease the fuel consumption, a new flight mode is being considered for twin-engine helicopters, in which one engine is put into sleeping mode (a mode in which the gas generator is kept at a stabilized, sub-idle speed by means of an electric motor, with no combustion), while the remaining engine operates at nominal load. The restart of the engine in sleeping mode is therefore deemed critical for safety reasons. This efficient new flight mode has raised the interest in the modeling of the restart of a turboshaft engine. In this context, the initial conditions of the simulations are better known relative to a ground start, in particular the air flow through the gas generator is constant, the fuel and oil system states are known and temperatures of the casings are equal to ambient. During the restart phase of the engine, the gas generator speed is kept at constant speed until the light-up is detected by a rise in inter-turbine temperature, then the starter torque increases, accelerating the engine towards idle speed. In this paper, the modeling of the acceleration of the gas generator from light-up to idle and above idle speeds is presented. Details on the light-up process are not addressed here. The study is based on the high-fidelity aero-thermodynamic restart model that is currently being developed for a 2000 horse power, free turbine turboshaft. In this case, the term high-fidelity refers not only to the modeling of the flow path components but it also includes all the subsystems, secondary air flows and controls with a high level of detail. The physical phenomena governing the acceleration of the turboshaft engine following a restart — mainly the transient evolution of the combustion efficiency and the power loss by heat soakage — are discussed in this paper and modeling solutions are presented. The results of the simulations are compared to engine test data, highlighting that the studied phenomena have an impact on the acceleration of the turboshaft engine and that the model is able to correctly predict acceleration trends.

scholarly journals Effects of Plateau Environment on Combustion and Emission Characteristics of a Plateau High-Pressure Common-Rail Diesel Engine with Different Blending Ratios of Biodiesel

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 550
Author(s):  
Guohai Jia ◽  
Guoshuai Tian ◽  
Daming Zhang
Keyword(s):  
High Pressure ◽  
Diesel Engine ◽  
Heat Release ◽  
Mass Fraction ◽  
Combustion Temperature ◽  
Common Rail ◽  
Maximum Temperature ◽  
Emission Characteristics ◽  
Mass Fractions ◽  
Maximum Combustion Temperature

Taking a plateau high-pressure common-rail diesel engine as the research model, a model was established and simulated by AVL FIRE according to the structural parameters of a diesel engine. The combustion and emission characteristics of D, B20, and B50 diesel engines were simulated in the plateau atmospheric environment at 0 m, 1000 m, and 2000 m. The calculation results show that as the altitude increased, the peak in-cylinder pressure and the cumulative heat release of diesel decreased with different blending ratios. When the altitude increased by 1000 m, the cumulative heat release was reduced by about 5%. Furthermore, the emission trend of NO, soot, and CO was to first increase and then decrease. As the altitude increased, the mass fraction of NO emission decreased. As the altitude increased, the mass fractions of soot and CO increased. Additionally, when the altitude was 0 m and 1000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B20 were higher and more uniform. When the altitude was 2000 m, the maximum temperature, the mass fraction of OH, and the fuel–air ratio of B50 were higher and more uniform. Lastly, as the altitude increased, the maximum combustion temperature of D and B20 decreased, and combustion became more uneven. As the altitude increased, the maximum combustion temperature of B50 increased, and the combustion became more uniform. As the altitude increased, the fuel–air ratio and the mass fractions of OH and NO decreased. When the altitude increased, the soot concentration increased, and the distribution area was larger.

scholarly journals Analysis Combustion Efficiency in a Fluidized-Bed Combustor With a Modified Perforated Plate for Air Distribution

2021 ◽  
Author(s):  
Erdiwansyah Erdiwansyah ◽  
Mahidin Mahidin ◽  
Husni Husin ◽  
Nasaruddin Nasaruddin ◽  
Muhtadin Muhtadin ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Perforated Plate ◽  
Combustion Efficiency ◽  
Biomass Waste ◽  
Transfer Rates ◽  
Burn Out ◽  
Maximum Combustion Temperature ◽  
Solid Biomass ◽  
Fluidized Bed Combustor

Abstract Combustion efficiency is one of the most important parameters, especially in the FBC combustion chamber. Investigations into the efficiency of combustion in FBC fuels using solid biomass waste fuels in recent years are increasingly in demand by researchers around the world. Specifically, this study aims to calculate the combustion efficiency in the FBC combustion chamber. Combustion efficiency is calculated based on combustion results from modification of hollow plates in the FBC combustion chamber. The modified hollow plate aims to control combustion so that the fuel incorporated can burn out and not saturate. The combustion experiments were tested using palm oil biomass solid waste fuels such as PKS, OPM, and EFB. The results of the measurements showed that the maximum combustion temperature for MCC fuel reached 863oC for M1 and 887oC on M2. The maximum combustion temperature measurements for M1 and M2 from OPM fuel testing reached 898oC and 858oC, respectively, while the maximum combustion temperature for EFB fuel was 667oC andM2 847oC, respectively. The rate of combustion efficiency with the modification of the hole plate in the FBC combustion chamber reached 96.2%. Thermal efficiency in FBC combustion chamber for OPM 72.62%, MCC 70.03%, and EFB 52.43%. The highest heat transfer rates for OPM fuel reached 7792.36 w/m, MCC 7167.38 w/m, and EFB 5127.83 w/m. Thus, modification of the holed plate in the FBC chamber showed better performance of the plate without modification.

scholarly journals Analysis Combustion Efficiency in a Fluidized-Bed Combustor With a Modified Perforated Plate for Air Distribution

2021 ◽  
Author(s):  
Erdiwansyah Erdiwansyah ◽  
Mahidin Mahidin ◽  
Husni Husin ◽  
Nasaruddin Nasaruddin ◽  
Muhtadin Muhtadin ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Combustion Temperature ◽  
Perforated Plate ◽  
Combustion Efficiency ◽  
Biomass Waste ◽  
Transfer Rates ◽  
Burn Out ◽  
Maximum Combustion Temperature ◽  
Solid Biomass ◽  
Fluidized Bed Combustor

Abstract Combustion efficiency is one of the most important parameters, especially in the FBC combustion chamber. Investigations into the efficiency of combustion in FBC fuels using solid biomass waste fuels in recent years are increasingly in demand by researchers around the world. Specifically, this study aims to calculate the combustion efficiency in the FBC combustion chamber. Combustion efficiency is calculated based on combustion results from modification of hollow plates in the FBC combustion chamber. The modified hollow plate aims to control combustion so that the fuel incorporated can burn out and not saturate. The combustion experiments were tested using palm oil biomass solid waste fuels such as PKS, OPM, and EFB. The results of the measurements showed that the maximum combustion temperature for MCC fuel reached 863oC for M1 and 887oC on M2. The maximum combustion temperature measurements for M1 and M2 from OPM fuel testing reached 898oC and 858oC, respectively, while the maximum combustion temperature for EFB fuel was 667oC andM2 847oC, respectively. The rate of combustion efficiency with the modification of the hole plate in the FBC combustion chamber reached 96.2%. Thermal efficiency in FBC combustion chamber for OPM 72.62%, MCC 70.03%, and EFB 52.43%. The highest heat transfer rates for OPM fuel reached 7792.36 w/m, MCC 7167.38 w/m, and EFB 5127.83 w/m. Thus, modification of the holed plate in the FBC chamber showed better performance of the plate without modification.

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