Effect of thermal input, excess air coefficient and combustion mode on natural gas MILD combustion in industrial-scale furnace

Fuel ◽  
2021 ◽  
Vol 302 ◽  
pp. 121179
Author(s):  
Mingming Huang ◽  
Ruichuan Li ◽  
Jikang Xu ◽  
Shen Cheng ◽  
Haoxin Deng ◽  
...  
Keyword(s):  
Natural Gas ◽  
Industrial Scale ◽  
Combustion Mode ◽  
Mild Combustion ◽  
Excess Air ◽  
Excess Air Coefficient

scholarly journals Evaluation of reduced chemical kinetic mechanisms used for modeling mild combustion for natural gas

2009 ◽  
Vol 13 (3) ◽  
pp. 131-137 ◽  
Author(s):  
Mohamed Hamdi ◽  
Hmaeid Benticha ◽  
Mohamed Sassi
Keyword(s):  
Natural Gas ◽  
Chemical Kinetic ◽  
Gas Temperature ◽  
Combustion Mode ◽  
Reduced Mechanism ◽  
Mild Combustion ◽  
Reduced Chemistry ◽  
Key Species ◽  
Kinetic Mechanisms ◽  
Step Mechanism

A numerical and parametric study was performed to evaluate the potential of reduced chemistry mechanisms to model natural gas chemistry including NOx chemistry under mild combustion mode. Two reduced mechanisms, 5-step and 9-step, were tested against the GRI-Mech3.0 by comparing key species, such as NOx, CO2 and CO, and gas temperature predictions in idealized reactors codes under mild combustion conditions. It is thus concluded that the 9-step mechanism appears to be a promising reduced mechanism that can be used in multi-dimensional codes for modeling mild combustion of natural gas.

scholarly journals Numerical investigation of lambda-value prechamber ignition in heavy duty natural gas engine

2020 ◽  
Vol 181 (2) ◽  
pp. 31-39
Author(s):  
Ireneusz PIELECHA
Keyword(s):  
Natural Gas ◽  
Stoichiometric Composition ◽  
Combustion Process ◽  
Strong Relationship ◽  
Heavy Duty ◽  
Excess Air ◽  
Excess Air Coefficient ◽  
Lean Mixtures ◽  
A Charge ◽  
The Impact

Turbulent Jet Ignition systems are mainly dedicated to the combustion of lean mixtures of natural gas in heavy duty engines. The use of such a system in combination with lean mixtures leads to an increase in its overall efficiency. The article presents simulation analyzes of the impact of the excess air coefficient occurring in prechamber on the combustion process: combustion indicators and emission indicators. Tests on a single-cylinder engine with a displacement of about 4 dm3 at medium mixture (IMEP = 1.0 MPa) were carried out using the AVL Fire software. It was found that the incineration of global lean mixtures (lambda = 2) is effective when initiating this process (in the prechamber) with a charge of a stoichiometric composition. A strong relationship was found between the thermodynamic indicators in both prechamber and main chamber and the excess air coefficient initiating combustion.

Effect of Chemical Hythane Composition on Pressure in Combustion Chamber of Engine

2019 ◽  
pp. 36-42
Author(s):  
A. P. Shaikin ◽  
I. R. Galiev
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Power Plants ◽  
Engine Speed ◽  
Combustion Engine ◽  
Fuel Mixture ◽  
Maximum Pressure ◽  
Chamber Volume ◽  
Excess Air ◽  
Scientific Papers

The article analyzes the influence of chemical composition of hythane (a mixture of natural gas with hydrogen) on pressure in an engine combustion chamber. A review of the literature has showed the relevance of using hythane in transport energy industry, and also revealed a number of scientific papers devoted to studying the effect of hythane on environmental and traction-dynamic characteristics of the engine. We have studied a single-cylinder spark-ignited internal combustion engine. In the experiments, the varying factors are: engine speed (600 and 900 min-1), excess air ratio and hydrogen concentration in natural gas which are 29, 47 and 58% (volume).The article shows that at idling engine speed maximum pressure in combustion chamber depends on excess air ratio and proportion hydrogen in the air-fuel mixture – the poorer air-fuel mixture and greater addition of hydrogen is, the more intense pressure increases. The positive effect of hydrogen on pressure is explained by the fact that addition of hydrogen contributes to increase in heat of combustion fuel and rate propagation of the flame. As a result, during combustion, more heat is released, and the fuel itself burns in a smaller volume. Thus, the addition of hydrogen can ensure stable combustion of a lean air-fuel mixture without loss of engine power. Moreover, the article shows that, despite the change in engine speed, addition of hydrogen, excess air ratio, type of fuel (natural gas and gasoline), there is a power-law dependence of the maximum pressure in engine cylinder on combustion chamber volume. Processing and analysis of the results of the foreign and domestic researchers have showed that patterns we discovered are applicable to engines of different designs, operating at different speeds and using different hydrocarbon fuels. The results research presented allow us to reduce the time and material costs when creating new power plants using hythane and meeting modern requirements for power, economy and toxicity.

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.

Corrigendum to “Data driven analysis and prediction of MILD combustion mode” [Combust. Flame 223 (2021) 474–485]

2021 ◽  
Vol 227 ◽  
pp. 481-482
Author(s):  
Kherlen Jigjid ◽  
Chitoshi Tamaoki ◽  
Yuki Minamoto ◽  
Ryota Nakazawa ◽  
Nakamasa Inoue ◽  
...  
Keyword(s):  
Data Driven ◽  
Combustion Mode ◽  
Mild Combustion

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Xiaoxiao Meng ◽  
Wei Zhou ◽  
Emad Rokni ◽  
Honghua Zhao ◽  
Rui Sun ◽  
...  
Keyword(s):  
Gas Phase ◽  
Ignition Delay Time ◽  
Fixed Bed ◽  
Combustion Efficiency ◽  
Fixed Bed Reactor ◽  
Corn Straw ◽  
Excess Air ◽  
Burning Rates ◽  
Excess Air Coefficient ◽  
Hazardous Pollutants

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

Numerically Study on Combustion and NOx Emission Characteristics in Tangentially Fired Boiler Co-Firing Semi-Coke

2018 ◽  
Author(s):  
Yongbo Du ◽  
Chang'an Wang ◽  
Pengqian Wang ◽  
Qiang Lv ◽  
Defu Che
Keyword(s):  
Bituminous Coal ◽  
Combustion Efficiency ◽  
Low Rank ◽  
Operation Performance ◽  
Combustion Heat ◽  
Practical Utilization ◽  
Excess Air ◽  
Utility Boilers ◽  
Excess Air Coefficient ◽  
Char Burnout

Semi-coke is a specific solid fuel, which is mainly produced by upgrading low-rank coal. The poor reactivity of semi-coke makes a difficulty to its practical utilization in utility boilers. Previous research was mainly focused on the combustion behavior of semi-coke, while the industrial application has to be understood. In this paper, the effect of co-firing semi-coke and bituminous coal on the operation performance of pulverized boiler was numerically studied. The work was conducted on a 300 MW tangentially fired boiler, and the temperature distribution, the char burnout and NOx production were mainly examined. The results indicate that the incomplete combustion heat loss drops with the increase in semi-coke blending ratio. The NOx concentration increases from 186 mg/Nm3 for only firing the bituminous coal to 200, 214, and 255 mg/Nm3, when the blending ratio was 17%, 33% and 50%, respectively. With enhancing excess air coefficient for the co-firing condition, the combustion efficiency got improved, while NOx production increased very slightly. In general, the boiler is well adapted to co-firing semi-coke, and the semi-coke blending ratio of 1/3 with an excess air coefficient of 1.235 is recommended.

Sign in / Sign up

Export Citation Format

Share Document