Mechanism For Methane Combustion Research Articles

Development of a Reduced Mechanism for Methane Combustion in OpenFOAM: A Computational Approach for Efficient and Accurate Simulations

The primary aim of this study is to develop a more efficient reaction mechanism for accurately simulating methane combustion, with a specific focus on ignition delay, laminar flame speed, and 2-D simulated flames, while also reducing computational time. Ten reduced reaction mechanisms for methane combustion were evaluated, with only one, "SK30," meeting the required accuracy standards. However, SK30 proved to be computationally intensive when simulating a 2-D premixed flame at a microscale. To address this challenge, a two-step reduction process was implemented. Firstly, an automated algorithm utilized direct relation graphs and sensitivity analysis with ignition delays as a reference to streamline the mechanism while maintaining accuracy. Subsequently, the second step involved identifying key reactions that had a more significant impact on flame speed than ignition delay through sensitivity analysis. Any missing reactions were then added judiciously, prioritizing the retrieval of the missing but important reactions to overall accuracy while minimizing computational cost. This process resulted in a novel mechanism comprising 25 species and 132 reactions for methane-air combustion. The validity of this mechanism was confirmed through comparison with a benchmark model, demonstrating satisfactory agreement in 1-D flame speed and 2-D premixed flame modeling. Most notably, the new mechanism substantially reduced processing time, achieving a 50% speedup compared to SK30.

A simplified mechanism of hydrogen addition to methane combustion for the pollutant emission characteristics of a gas-fired boiler

The reaction mechanism of hydrogen-enriched methane (HEM) combustion is significant in the combustion process. In this study, four widely used reaction mechanisms for methane combustion are simplified to investigate the pollutant emission characteristics of a gas-fired boiler used for HEM combustion. The laminar burn velocity (LBV) and ignition delay time (IDT) of the four detailed and four simplified mechanisms are compared, and the simplified San Diego mechanism is identified as the optimal mechanism using relative error and population standard deviation analysis. The temperatures and key components of the simplified San Diego mechanism are also compared with those of the detailed San Diego mechanism under various XH2. Based on the simplified San Diego mechanism, a chemical reactor network model for gas-fired boilers is further established to investigate the pollutant emissions of HEM combustion, in which the hydrogen doping ratio XH2 ranged from 0 to 80% and the inlet air and fuel temperature Tin ranged from 300 K to 600 K. Results showed that at Tin = 300 K with XH2 ranging from 0 to 80%, the mole fraction of NO increase by 1.94 times because of the increase in peak flame temperature; moreover, the mole fractions of N2O, CO, and CO2 decrease by approximately 25%, 50%, and 52%, respectively. With XH2 ranging from 0 to 40% and Tin ≥ 500 K, the mole fraction of NO decreases because the reduction reaction of NO + H = N + OH is promoted, whereas when XH2 is further increased to 80%, the increased H promotes the increase in NO again. CO emissions decreased as XH2 increased from 0 to 80%, whereas they increased by approximately 1.3 times as Tin increased from 300 K to 600 K because of the CO2 decomposition. N2O emissions decreased by more than 25% as XH2 increased from 0 to 80%. Additionally, CO2 emissions decrease by 52% with an increase in XH2 and by only 5% with an increase in Tin, indicating that XH2 has a larger impact on CO2 emissions. The proposed optimal HEM combustion mechanism is conducive to improving the efficiency of numerical calculations.

Measurement and Kinetics Prediction of Undiluted Methane–Oxygen Laminar Flame Speeds

This study presents new laminar flame speed () data for a wide range of equivalence ratios () at low pressure (0.5 atm) and multiple initial pressures (0.5–3 atm) at an equivalence ratio far from stoichiometry (). All experiments were conducted at room temperature using spherically expanding flames. At 0.5 atm, peaked slightly lean, reaching a maximum of 411 cm/s near . Far from stoichiometry, was approximately 72 and 34 cm/s at and 2.4, respectively. predictions were computed using several commonly cited chemical kinetics mechanisms for methane combustion, with performance approximately the same for all mechanisms. Every mechanism underpredicted at 0.5 atm for , with performance especially poor near stoichiometry ( underprediction near the peak). For , experiments were conducted for pressures from 0.5 to 3.0 atm, showing that varies approximately according to the power law . The mechanisms captured this pressure dependency, with GRI-Mech 3.0 performing especially well. Sensitivity analysis shows that many reaction adjustments are necessary to solve the underprediction near stoichiometry, with potentially a reaction of interest.

Numerical investigation of hydrogen addition effects to a methane-fueled high-pressure combustion chamber

To get a general understanding of hydrogen fuel usage in a real-condition high-pressure industrial gas turbine burner operating at 15 atm pressure, the effects of hydrogen addition to methane fuel are studied numerically. Methane-hydrogen premixed fuel-lean flame is investigated while hydrogen is substituted for methane at a fixed fuel and air mass flow rate at the burner inlet. Steady-state reacting and swirling flow equations (RANS) are solved using the standard k−ε model as the turbulence model. A detailed methane combustion mechanism GRI 2.11 is used to simulate methane-hydrogen combustion with Finite Rate formulation more accurately. Temperature and axial velocity variation and important pollutant species emissions such as CO, CO2, and NOx were investigated at the combustion chamber exit. Flame shape, flow pattern, and flame location variation with hydrogen addition were studied due to hydrogen flashback limits. The hydrogen addition leads to higher temperatures inside the burner and the hot zone inside the combustion chamber extends and moves toward the fuel inlet. Flow structure including recirculation zones change with hydrogen addition. CO emission increases by hydrogen addition to the fuel mixture near the burner exit while CO2 mass fraction is reduced. A significant increase in NO mass fraction with hydrogen addition was observed near the burner exit due to higher temperature.

Numerical analysis of the distribution of combustion products from methane explosions in a full-scale tunnel using all-speed CFD code GASFLOW-MPI

ABSTRACT Methane explosions are among the main hazards in coal mines. Shock waves from methane explosions can cause damage near the explosion site, and combustion products can spread along the tunnel to locations far from the explosion source and endanger the lives and health of personnel. Therefore, the study of the propagation patterns of methane explosion shock waves and the distribution of high-temperature combustion products in tunnels. has significance for emergency decision-making in the event of methane explosions in a mine. This study uses the 3D Computational Fluid Dynamics (CFD) program GASFLOW-MPI, which models the one-step methane combustion mechanism with the addition of a heat transfer model. The methane explosion process is simulated and reproduced at the Lake Lynn Experimental Mine (LLEM) to analyze the process of gas deflagration. The results reveal that the overpressure in the tunnel after the methane explosion oscillates and decays with time. Gaseous products of the explosion “expand and compress” and flow back and forth in accordance with the oscillation of overpressure. The maximum expansion ratio of the CO2 concentration isosurfaces of 0.5% in the heat transfer simulation is 6.21, whereas the volume expansion ratio is 3.78 once the flow field stabilizes. The distribution of combustion products along the alleyway exhibits a Gaussian decay trend. The range of gaseous product distribution and temperature fields in the adiabatic tunnel is significantly higher than that in the heat transfer simulations, thus indicating that heat loss significantly influences the temperature characteristics and distribution pattern of combustion products in the full-scale tunnel.

The high activity of Co-Mn-based solid solution catalysts for lean methane combustion

Developing non-noble metal-based catalysts for methane combustion with high catalytic activity and stability is important in the new context of a changing global energy landscape. In this study, we reported an Co5Mn1-O catalyst achieved 90% conversion of methane to CO2 at 305 °C, which was about 60 ℃ lower than the catalysts reported. The synthetic strategy via lattice distortion that inhibits the deep oxidation of Mn2+ with prepared a highly catalytic reactive Co-Mn-based solid solution material. The results show that introduction of Mn atoms into the Co3O4 spinel structure caused lattice distortion, which modulated the oxygen coordination environment and oxygen vacancies of the catalyst, and the Co5Mn1-O (Optimum) catalyst prepared under optimized conditions obtained excellent methane activation capacity and lattice oxygen mobility. The higher lattice oxygen mobility of the Co5Mn1-O catalyst facilitated the adsorption, activation, and oxidation of methane, especially the rate-determining step of methane oxidation, the conversion of CH4 to CH3-. The conversion rate decreases slightly in the presence of 5 vol% or 10 vol% H2O, but it also still maintained good catalytic activity and stability under high temperatures and long-term reactions. In addition, in situ infrared specra was used to explore the reaction mechanism of methane combustion under real reaction conditions.

Molecular dynamics simulation on CH4 combustion in CO2/O2/N2 atmosphere subjected to electric field

ABSTRACT In this paper, the CH4 combustion characteristics in CO2/O2/N2 atmosphere subjected to electric field were studied by the molecular dynamics simulation method. Conventional and unique pathways were obtained. The evolution law of reactants and main products and the first reaction time of main intermediates under the influence of different electric field intensities were analysed. Results showed that the addition of external electric fields increased conventional responses and species diversity. The generation of new pathways induced the production of new species, and the further reactions of new species produced other new pathways, thus accelerating the generation of new pathways and species in the electric field. It was noteworthy that, the applied external electric field could advance the reaction start time and reinforce the combustion process, but its effect on the reaction rate was highly nonlinear. The CH4 reaction with CO2 was significantly intensified at E ≥ 105 V/m, while suppressed at E = 104 V/m. Furthermore, electric fields could promote the oxidation degree of CH4, especially at E = 106 V/m. The studies provide theoretical guidance for revealing the mechanism of methane combustion under a high concentration CO2 atmosphere and promoting the efficient capture of CO2.

Investigation on the reaction mechanism of methane combustion near flammability limits at elevated pressures and temperaturaes

Combustible gas explosions may occur at elevated pressure and temperature of wellbore conditions. To better understand and protect against wellbore explosion, it is necessary to study the combustion mechanism of methane at elevated pressure and temperature conditions. In this study, combustion mechanisms near the stoichiometric concentration as well as the flammability limit were investigated using a one-dimensional premixed laminar flame speed model based on the GRI 3.0 mechanism. The effects of initial pressure and initial temperature on flame temperature were analyzed. The main free radicals and reactions at different conditions were determined by sensitivity analysis. The reaction rates of the main reactions were comprehensively analyzed with previous experimental results of the flammability limit at different conditions. The mechanism of how initial pressure and initial temperature affects the flammability limit was determined. The results showed that the radical HO2 and its involved reaction HO2+CH3OH + CH3O play a crucial role in the methane combustion process at elevated pressure and temperature conditions. The initial pressure and initial temperature quantitatively affect the flammability limit mainly by affecting the reaction rates of the main reactions.

Mechanism and Kinetics of Methane Combustion. Part II: Potential Energy Surface for Hydrogen-Abstraction Reaction of CH4 + O(3P).

Methane combustion plays an important role in various fields such as combustion chemistry and atmospheric chemistry of the stratosphere. Highly accurate study of its initial reaction remains a key challenge. Here, through extensive studies with a state-of-the-art ab initio and neural network method, we present a potential energy surface of the O(3P) + CH4 → OH + CH3 reaction on the ground state 13A and the first excited state 23A. In this work, the energies of 10 167 points covering all important regions are obtained with state-averaged complete active space self-consistent field calculations and then fitted using the Levenberg-Marquardt algorithm with a root-mean-square error of 0.391 and 0.442 kcal/mol for the 13A and 23A states, respectively. This study explores the characteristics of the radical van der Waals (VdW) complex and reveals a detailed mechanism of the methane combustion initial reaction. Within the scope of this mechanism, this surface gives a fairly accurate description of the regions around the saddle point, conical intersection, and vdW wells in the entrance for efficient computational simulations. As a theoretical study on a prototypical polyatomic reaction, it is hopeful that this work will modify our understanding of the primary process in hydrocarbon combustion.

Adaptability of different mechanisms and kinetic study of methane combustion in steam diluted environments

The chemical kinetics of methane oxidation in a steam-diluted environment are studied in the present study. Various well-validated mechanisms for methane combustion are adopted and compared with experimental data. Ignition delay, laminar flame speed, and emissions for CH4 combustion with steam dilution are discussed. Cumulative relative error parameter was determined for all mechanisms considered in this study to evaluate the prediction level in quantifiable terms. Reaction pathways under no and steam-diluted environments are analyzed, and key elementary reactions and species are identified in these conditions. The analysis gives a relative idea of the applicability of some of the reduced mechanisms for the diluted steam conditions. This study aims to guide future computational fluid dynamics simulations to accurately predict combustion characteristics in these conditions. Computations of laminar flame speed from GRI-3.0, Aramco3.0, Curran, and San Diego mechanisms were the most precise under diluted steam conditions. Similarly, for the calculation of ignition delay of methane under the steam dilution, the Aramco mechanism and the Curran’s mechanism were able to predict the experimentally observed values most closely. Sensitivity study for the OH concentrations shows that the H-abstraction of methane from OH radicals has an opposing trend with dilution for Aramco and GRI-3.0 mechanism. On the other hand, CO and NO emissions were reduced significantly, with the dilution increased from 0 to 20%. The third-body effect of steam is observed to dominate the deviation observed between the detailed and reduced mechanism. For low operating pressure conditions, the GRI-3.0 mechanism gives an excellent prediction, whereas, for applications like gas turbines and furnaces, Aramco-3.0 and Curran mechanisms can be adopted to give good results. The San Diego mechanism can be chosen for low computational facility purposes as it shows very good predictions for ignition delay and laminar flame speed computations.

Effects of water vapor on auto-ignition characteristics and laminar flame speed of methane/air mixture under engine-relevant conditions

In this paper, the effects of water vapor on auto-ignition characteristics and laminar flame speed of the methane/air mixture were numerically simulated by using the Chemkin code under the engine-relevant conditions. Different methane combustion mechanisms were separately simulated under the same boundary conditions and compared to the experimental data obtained from the literature. Then, the detailed methane combustion mechanism was selected to investigate the effects of water vapor on the auto-ignition characteristics of the methane/air mixture and methane/hydrogen/air mixture under the relative high pressure condition. In addition, the effects of water vapor on the laminar flame speed of methane/air and methane/hydrogen/air mixture was also studied. Furthermore, the chemical, thermal and dilution effects of the water vapor on the laminar flame speed of methane/air were quantitatively evaluated. Last, the effects of initial temperature and pressure on the laminar flame speed of methane/air were also analyzed based on the detailed methane combustion mechanism. The results indicated that the ignition delay time of the methane/air was increased with increasing water vapor ratio. In addition, the dilution and thermal effects of the water vapor played the decisive roles in the laminar flame speed of the methane/air mixture compared to its chemical effect. Furthermore, the laminar flame speed and adiabatic combustion temperature of the methane/air were decreased with increasing water vapor ratio. Moreover, the formation and oxidation rates of the H, O and OH radicals during the methane/air combustion were prohibited with adding water vapor.

Methane combustion over palladium catalyst within the confined space of MFI zeolite

Isolated cationic Pd species encapsulated in MFI zeolite, i.e., Pd@MFI, have been successfully prepared via in situ hydrothermal route followed by oxidative treatment. The as-prepared Pd@MFI samples are investigated as promising catalysts in the reaction of methane combustion. Typically, Pd@H-ZSM-5 shows remarkable activity in methane catalytic combustion with a low apparent activation energy value of 70.7 kJ/mol as well as good catalytic stability even in excess water vapor. Detailed characterization results demonstrate the strong interaction between Pd sites and zeolite framework in Pd@ZSM-5 and the efficient stabilization of isolated Pd sites by zeolite thereof. Spectroscopy analyses reveal that the presence of Brønsted acid sites is beneficial to methane adsorption and its subsequent activation on adjacent Pd sites, constructing cooperation between Brønsted acid sites and Pd sites within the confined space of MFI zeolite toward high-efficiency methane catalytic combustion. The reaction mechanism of methane combustion catalyzed by Pd@H-ZSM-5 model catalyst is finally discussed.

Evaluation of Chemical Kinetic Mechanisms for Methane Combustion: A Review from a CFD Perspective

Methane is an important fuel for gas turbine and gas engine combustion, and the most common fuel in fundamental combustion studies. As Computational Fluid Dynamics (CFD) modeling of combustion becomes increasingly important, so do chemical kinetic mechanisms for methane combustion. Kinetic mechanisms of different complexity exist, and the aim of this study is to review commonly used detailed, reduced, and global mechanisms of importance for CFD of methane combustion. In this review, procedures of relevance to model development are outlined. Simulations of zero and one-dimensional configurations have been performed over a wide range of conditions, including addition of H2, CO2 and H2O, and the results are used in a final recommendation about the use of the different mechanisms. The aim of this review is to put focus on the importance of an informed choice of kinetic mechanism to obtain accurate results at a reasonable computational cost. It is shown that for flame simulations, a reduced mechanism with only 42 irreversible reactions gives excellent agreement with experimental data, using only 5% of the computational time as compared to the widely used GRI-Mech 3.0. The reduced mechanisms are highly suitable for flame simulations, while for ignition they tend to react too slow, giving longer than expected ignition delay time. For combustible mixtures with addition of hydrogen, carbon dioxide, or water, the detailed as well as reduced mechanisms generally show as good performance as for the corresponding simulations of pure methane/air mixtures.

Study on effect CO2 diluent on fuel cоmbustion in methane-oxygen combustion chambers

Studying closed gas turbine cycles on supercritical carbon dioxide is currently a promising issue in the development of power energy sector in terms of increasing energy efficiency and minimizing greenhouse gas emissions into the atmosphere. Combustion of methane with oxygen in the combustion chamber occurs not in the nitrogen environment, but in the environment of carbon dioxide, that is the working fluid of the cycle, which is an inhibitor of chemical reactions. A large mass content of such a diluent of the reaction mixture in the volume of the chamber leads to the risks of significant chemical underburning, efficiency decrease of the combustion chamber and the cycle as a whole. The aim of the research is to study the kinetic parameters of the combustion of methane with oxygen in a supercritical CO2 diluent medium to ensure reliable and stable combustion of fuel by assessing the degree of the inhibitory effect of CO2 and determining its permissible amount in the active combustion zone of the combustion chamber. The research method is a numerical simulation of turbulent-kinetic processes of methane combustion in the combustion chamber using the reduced methane combustion mechanism. Ansys Fluent software package has been used. The authers have studied the impact of CO2 diluent on fuel cоmbustion in methane-oxygen combustion chambers. It is found that the combustor flame stabilization takes place if the content of СО2 diluent supplied to the mixture with oxidizer is 0,46–0,5 of mass fraction; additional СО2 diluent forms local low temperature zones which slow down the combustion process. When this happens, adding cooling СО2 into the flame stabilization zone should be eliminated. The study has found that no more than 20 % of the total carbon dioxide content should be supplied to the combustion chamber; to stabilize the flame and reduce its length, it is necessary to install blades to swirl the fuel and oxidizer mixed with CO2 at the inlet of the combustion chamber; CO2 supply for cooling should be carried out not less than 130 mm away from the burner mouth.

Modeling of turbulent flames with the large eddy simulation–probability density function (LES–PDF) approach, stochastic fields, and artificial neural networks

This work proposes a chemical mechanism tabulation method using artificial neural networks (ANNs) for turbulent combustion simulations. The method is employed here in the context of the Large-Eddy Simulation (LES)–Probability Density Function (PDF) approach and the method of stochastic fields for numerical solution, but can also be employed in other methods featuring real-time integration of chemical kinetics. The focus of the paper is on exploring an ANN architecture aiming at improved generalization, which uses a single multilayer perceptron (MLP) for each species over the entire training dataset. This method is shown to outperform previous approaches which take advantage of specialization by clustering the composition space using the Self-Organizing Map (SOM). The ANN training data are generated using the canonical combustion problem of igniting/extinguishing one-dimensional laminar flamelets with a detailed methane combustion mechanism, before being augmented with randomly generated data to produce a hybrid random/flamelet dataset with improved composition space coverage. The ANNs generated in this study are applied to the LES of a turbulent non-premixed CH4/air flame, Sydney flame L. The transported PDF approach is used for reaction source term closure, while numerical solution is obtained using the method of stochastic fields. Very good agreement is observed between direct integration (DI) and the ANNs, meaning that the ANNs can successfully replace the integration of chemical kinetics. The time taken for the reaction source computation is reduced 18-fold, which means that LES–PDF simulations with comprehensive mechanisms can be performed on modest computing resources.

Реализация кинетических механизмов горения метана на примере расширения функциональных возможностей физико-химических библиотек совместно с решателем reactingPimpleCentralFoam

The possibility of using reduced combustion mechanisms for hydrocarbon fuels in solvers developed and used at ISP RAS is investigated. These mechanisms contain smaller number of stages and substances appearing in them, but they allow obtaining results in a good agreement with experimental data in a much shorter calculation time. The comparison is made with the results obtained with using the Moscow Aviation Institute solvers. A modified mechanism of methane combustion is considered. It can be extended to describe the chemical reaction processes in other hydrocarbon-oxygen mixtures. The choice of methane is due to the prospects of this fuel at the present time. As the first test problem, a standard chemFoam is used. This solver was designed to demonstrate the occurrence of chemical reactions in a computational domain consists of one cell only. The ignition delay and the parameter values of the thermodynamic equilibrium state reached are taken as the comparison criteria. The second test problem is the flow modeling in a shock tube after the shock wave has been reflected from the wall. This problem is considered in a three-dimensional domain using the ISP RAS reactingPimpleCentralFoam solver. Results were compared with ones obtained by grid-characteristic and Godunov's methods in one-dimensional nonstationary calculations. The effects of viscosity, thermal conductivity and diffusion are not taken into account. The distributions of the flow parameters behind the reflected shock wave are obtained. Results are analyzed depending on the value of the falling shock wave Mach number. Estimates of the possible application of this reduced mechanism are given.

Reduced Methane Combustion Mechanism and Verification, Validation, and Accreditation (VV&A) in CFD for NO Emission Prediction

In order to obtain a reduced methane combustion mechanism for predicting combustion field and pollutants accurately in CFD simulations with a lower computational cost, a reduced mechanism with 22 species and 65 steps of reactions from GRI-Mech 3.0 was obtained by direct relation graph method and sensitivity analysis. The ideal reactor calculation and VVA the temperature field and species can be predicted accurately in CFD simulations (RANS and LES models), and the NO prediction error of an industrial gas turbine combustor outlet is less than 2×10−6. The proposed mechanism has high engineering values.

Turbulence/flame/wall interactions in non-premixed inclined slot-jet flames impinging at a wall using direct numerical simulation

In the present work, three-dimensional turbulent non-premixed oblique slot-jet flames impinging at a wall were investigated using direct numerical simulation (DNS). Two cases are considered with the Damköhler number (Da) of case A being twice that of case B. A 17 species and 73-step mechanism for methane combustion was employed in the simulations. It was found that flame extinction in case B is more prominent compared to case A. Reignition in the lower branch of combustion for case A occurs when the scalar dissipation rate relaxes, while no reignition occurs in the lower branch for case B due to excessive scalar dissipation rate. A method was proposed to identify the flame quenching edges of turbulent non-premixed flames in wall-bounded flows based on the intersections of mixture fraction and OH mass fraction iso-surfaces. The flame/wall interactions were examined in terms of the quenching distance and the wall heat flux along the quenching edges. There is essentially no flame/wall interaction in case B due to the extinction caused by excessive turbulent mixing. In contrast, significant interactions between flames and the wall are observed in case A. The quenching distance is found to be negatively correlated with wall heat flux as previously reported in turbulent premixed flames. The influence of chemical reactions and wall on flow topologies was identified. The FS/U and FC/U topologies are found near flame edges, and the NNN/U topology appears when reignition occurs. The vortex-dominant topologies, FC/U and FS/S, play an increasingly important role as the jet turbulence develops.

Towards Methane Combustion Mechanism on Metal Oxides Supported Catalysts: Ceria Supported Palladium Catalysts

The application of methane as a fuel in the automotive industry shows an increasing tendency, but its release into the atmosphere is detrimental due to its very high greenhouse effect. For this reason, new solutions for cleaning systems of exhaust gas from methane engines are in demand. This study focuses on thorough characterisation of active centres, structure–activity relationships, and reaction steps on palladium ceria supported catalysts of different loading, using the in situ FTIR method with different surface probe molecules. The results show substantial activity of low loading Pd/CeO2 catalyst, correlated with its high dispersion. Three types of active centres were found on the catalyst surface: acidic and redox on both the ceria and palladium oxide surfaces, and basic ones on the palladium oxide. The reaction on the Pd/CeO2 catalyst was shown to proceed via the formation of monodentates, which were a stable reaction intermediate in the temperature range between 150 and 250 °C. The assignment of the intermediates was supported by the in situ FTIR sorption experiments with CO, CH4 used as probe molecules.

WET BURNING – THE MODERN TREND IN ENVIRONMENTAL BENIGN FUEL COMBUSTION AND IN SOLUTION TO THE PROBLEM OF SUSTAINABLE DEVELOPMENT OF THE POWER GENERATION

The article considers the role and place of water and water vapor in combustion processes with the purpose of reduction the effluents of nitrogen oxides and carbon oxide. We have carried out the complex of theoretical and computational researches on reduction of harmful nitrogen and carbon oxides by gas fuel combustion in dependence on humidity of atmospheric air by two approaches: CFD modeling with attraction of DRM 19 chemical kinetics mechanism of combustion for 19 components along with Bowman’s mechanism used as “postprocessor” to determine the [NO] concentration; different thermodynamic models of predicting the nitrogen oxides NO formation. The numerical simulation of the transport processes for momentum, mass and heat being solved simultaneously in the united equations’ system with the chemical kinetics equations in frame of GRI methane combustion mechanism and NO formation calculated afterwards as “postprocessor” allow calculating the absolute actual [CO] and [NO] concentrations in dependence on combustion operative conditions and on design of furnace facilities. Prediction in frame of thermodynamic equilibrium state for combustion products ensures only evaluation of the relative value of [NO] concentration by wet combustion the gas with humid air regarding that in case of dry air – oxidant. We have developed the methodology and have revealed the results of numerical simulation of impact of the relative humidity of atmospheric air on harmful gases formation. Range of relative air humidity under calculations of atmospheric air under impact on [NO] and [CO] concentrations at the furnace chamber exit makes φ = 0 – 100%. The results of CFD modeling have been verified both by author’s experimental data and due comparing with the trends stated in world literature. We have carried out the complex of the experimental investigations regarding atmospheric air humidification impact on flame structure and environmental characteristics at natural gas combustion with premixed flame formation in open air. The article also proposes the methodology for evaluation of the nitrogen oxides formation in dependence on moisture content of burning mixture. The results of measurements have been used for verification the calculation data. Coincidence of relative change the NO (NOx) yield due humidification the combustion air revealed by means of CFD prediction has confirmed the qualitative and the quantitative correspondence of physical and chemical kinetics mechanisms and the CFD modeling procedures with the processes to be studied. A sharp, more than an order of reduction in NO emissions and simultaneously approximately a two-fold decrease in the CO concentration during combustion of the methane-air mixture under conditions of humidification of the combustion air to a saturation state at a temperature of 325 K.