Artykuły w czasopismach: „Hydrogen methane combustion”

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Zhao, Te, Chusheng Chen i Hong Ye. "CFD Simulation of Hydrogen Generation and Methane Combustion Inside a Water Splitting Membrane Reactor". Energies 14, nr 21 (1.11.2021): 7175. http://dx.doi.org/10.3390/en14217175.

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Hydrogen production from water splitting remains difficult due to the low equilibrium constant (e.g., Kp ≈ 2 × 10−8 at 900 °C). The coupling of methane combustion with water splitting in an oxygen transport membrane reactor can shift the water splitting equilibrium toward dissociation by instantaneously removing O2 from the product, enabling the continuous process of water splitting and continuous generation of hydrogen, and the heat required for water splitting can be largely compensated for by methane combustion. In this work, a CFD simulation model for the coupled membrane reactor was developed and validated. The effects of the sweep gas flow rate, methane content and inlet temperature on the reactor performance were investigated. It was found that coupling of methane combustion with water splitting could significantly improve the hydrogen generation capacity of the membrane reactor. Under certain conditions, the average hydrogen yield with methane combustion could increase threefold compared to methods that used no coupling of combustion. The methane conversion decreases while the hydrogen yield increases with the increase in sweep gas flow rate or methane content. Excessive methane is required to ensure the hydrogen yield of the reactor. Increasing the inlet temperature can increase the membrane temperature, methane conversion, oxygen permeation rate and hydrogen yield.

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Рубцов, Н. М., Б. С. Сеплярский, А. П. Калинин i К. Я. Трошин. "К 125-летию со дня рождения лауреата Нобелевской премии академика Николая Николаевича Семенова Цепной механизм воздействия добавок дихлордифторметана на горение водорода и метана в кислороде и воздухе". Журнал технической физики 91, nr 6 (2021): 893. http://dx.doi.org/10.21883/jtf.2021.06.50857.269-20.

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The effect of difluorodichloromethane additives on spark initiated combustion of hydrogen and methane in air and oxygen at atmospheric and reduced pressures was investigated. It has been found that the ignition concentration limit of the premixed hydrogen-air mixture in the presence of difluorodichloromethane at 1 atm exceeds 10%, while it has been shown for the first time that the ignition limit of the premixed methane-air mixture is 1% of difluorodichloromethane, which is thereby the most effective methane combustion inhibitor. This also means that the active combustion centers of hydrogen and methane, which determine the development of combustion, have a different chemical nature. Thus, the reaction including a difluorodichloromethane molecule resulting in the formation of HF (v = 2.3) during methane combustion should include a step involving the active methane combustion intermediate. Using hyperspectrometers of the visible and near-infrared ranges in the products of the oxidation reactions of hydrogen and methane in the presence of difluorodichloromethane, vibrationally excited HF molecules (v = 2.3) were first discovered. For the first time, it was found that HF molecules (v = 3) during methane combustion are formed at the moment when the maximum rate of chemical conversion is achieved, that is, reactions involving inhibitor molecules compete with the process of development of reaction chains. Keywords: chain burning, inhibition, methane, hydrogen, dichlorodifluoromethane, hyperspectrometer, high-speed color filming, radicals, excited particles.

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Taymarov, M. A., V. K. Ilyin, E. G. Chiklyaev i R. G. Sungatullin. "Features of application of the methane-hydrogen fraction as fuel for thermal power plant boiler". Power engineering: research, equipment, technology 21, nr 3 (29.11.2019): 109–16. http://dx.doi.org/10.30724/1998-9903-2019-21-3-109-116.

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The methane-hydrogen fraction is a gaseous hydrocarbon by-product during oil processing for obtaining petroleum products. Until recently, the methane-hydrogen fraction was used as furnace oil in internal technological processes at a refinery. Some of the low-calorie methane-hydrogen fraction was burned in flares. Driven by the prospect of the methane-hydrogen fraction use as a fuel alternative to natural gas for burning in thermal power plants boilers, it became necessary to study the methane-hydrogen fraction combustion processes in large volumes. The conversion of ON-1000/1 and ON-1000/2 furnaces from the combustion of the methane- hydrogen fraction with combustion heat of 25.45 MJ/m3 to the combustion of the composition with combustion heat of 18.8 MJ/m3 leads to a decrease in temperature in the flame core for 100 °C as an average. The intensity of flame radiation on the radiant tubes decreases. Therefore, the operation of furnaces during combustion of methane-hydrogen fraction with a low heat of combustion at the gas oil hydro-treating unit is carried out only with a fresh catalyst, which allows lower flame temperatures in the burner.The experiments to determine the concentration of nitrogen oxides NOx and the burning rate w of the methane-hydrogen fraction in the ON-1000/1 furnace and natural gas in the TGM-84A boiler, depending upon the heat of combustion Qnr were carried out. The obtained results showed that the increase in the hydrogen content Н2 from 10.05 % to 18.36% (by mass) results in an increase in the burning rate w by 45%. The burning rate of natural gas with methane CH4 content of 98.89% in the TGM-84A boiler is 0.84 m/s, i.e. it is 2.5 times lower than the burning rate of the methane- hydrogen fraction with H2 content of 10.05%. The distributions of heat flux from the flame qf over the burner height h in the TGM-84A boiler were obtained in case of natural gas burning and calculation of burning of the methane-hydrogen fraction with a hydrogen content of 10.05% and methane of 28.27%. The comparison of the obtained data shows that burning of methane- hydrogen fraction causes an increase in the incident heat flux qf at the outlet of the burner.

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Shchepakina, Elena Anatolievna, Ivan Alexandrovich Zubrilin, Alexey Yurievich Kuznetsov, Konstantin Dmitrievich Tsapenkov, Dmitry Vladimirovich Antonov, Pavel Alexandrovich Strizhak, Denis Vladimirovich Yakushkin, Alexander Gennadievich Ulitichev, Vladimir Alexandrovich Dolinskiy i Mario Hernandez Morales. "Physical and Chemical Features of Hydrogen Combustion and Their Influence on the Characteristics of Gas Turbine Combustion Chambers". Applied Sciences 13, nr 6 (15.03.2023): 3754. http://dx.doi.org/10.3390/app13063754.

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Hydrogen plays a key role in the transition to a carbon-free economy. Substitution of hydrocarbon fuel with hydrogen in gas turbine engines and power plants is an area of growing interest. This review discusses the combustion features of adding hydrogen as well as its influence on the characteristics of gas turbine combustion chambers as compared with methane. The paper presents the studies into pure hydrogen or methane and methane–hydrogen mixtures with various hydrogen contents. Hydrogen combustion shows a smaller ignition delay time and higher laminar flame speed with a shift in its maximum value to a rich mixture, which has a significant effect on the flashback inside the burner premixer, especially at elevated air temperatures. Another feature is an increased temperature of the flame, which can lead to an increased rate of nitrogen oxide formation. However, wider combustion concentration ranges contribute to the stable combustion of hydrogen at temperatures lower than those of methane. Along with this, it has been shown that even at the same adiabatic temperature, more nitrogen oxides are formed in a hydrogen flame than in a methane flame, which indicates another mechanism for NOx formation in addition to the Zeldovich mechanism. The article also summarizes some of the results of the studies into the effects of hydrogen on thermoacoustic instability, which depends on the inherent nature of pulsations during methane combustion. The presented data will be useful both to engineers who are engaged in solving the problems of designing hydrogen combustion devices and to scientists in this field of study.

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Herkowiak, Marcin, Barbara Łaska-Zieja, Andrzej Myczko i Edyta Wrzesińska-Jędrusiak. "Problems of Hydrogen Doping in the Methane Fermentation Process and of Energetic Use of the Gas Mixture". Applied Sciences 11, nr 14 (9.07.2021): 6374. http://dx.doi.org/10.3390/app11146374.

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This article discusses the technology for doping hydrogen into the fermenter to increase methane production and the amount of energy in the mixture. Hydrogen doping is anticipated to enable more carbon to be applied to produce methane. Hydrogen is proposed to be produced by using excess electricity from, for example, off-peak electricity hours at night. The possibilities of using a mixture of hydrogen and biogas for combustion in boilers and internal combustion engines have been determined. It has been proven that the volumetric addition of hydrogen reduces the heat of combustion of the mixture. Problems arising from hydrogen doping during the methane fermentation process have been identified.

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Zian, Norhaslina Mat, Hasril Hasini i Nur Irmawati Om. "Investigation of Syngas Combustion at Variable Methane Composition in Can Combustor Using CFD". Advanced Materials Research 1016 (sierpień 2014): 592–96. http://dx.doi.org/10.4028/www.scientific.net/amr.1016.592.

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This paper describes the analysis of the fundamental effect of synthetic gas combustion in a can-type combustor using Computational Fluid Dynamic(CFD). Emphasis is given towards the effect of variation of methane to the flame profile, temperature distribution and heat flux in the combustor. In this study, the composition of hydrogen in the syngas was fixed at 30% while methane and carbon monoxide were varied. Results show that the flame temperature and NOxemissions are highly dependent on the composition of methane in the syngas fuel. Nevertheless, the overall NOxemission for all cases is relatively lower than the conventional pure natural gas combustion.

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Wang, Kefu, Feng Li, Tao Zhou i Yiqun Ao. "Numerical Study of Combustion and Emission Characteristics for Hydrogen Mixed Fuel in the Methane-Fueled Gas Turbine Combustor". Aerospace 10, nr 1 (10.01.2023): 72. http://dx.doi.org/10.3390/aerospace10010072.

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The aeroderivative gas turbine is widely used as it demonstrates many advantages. Adding hydrogen to natural gas fuels can improve the performance of combustion. Following this, the effects of hydrogen enrichment on combustion characteristics were analyzed in an aeroderivative gas turbine combustor using CFD simulations. The numerical model was validated with experimental results. The conditions of the constant mass flow rate and the constant energy input were studied. The results indicate that adding hydrogen reduced the fuel residues significantly (fuel mass at the combustion chamber outlet was reduced up to 60.9%). In addition, the discharge of C2H2 and other pollutants was reduced. Increasing the volume fraction of hydrogen in the fuel also reduced CO emissions at the constant energy input while increasing CO emissions at the constant fuel mass flow rate. An excess in the volume fraction of added hydrogen changed the combustion mode in the combustion chamber, resulting in fuel-rich combustion (at constant mass flow rate) and diffusion combustion (at constant input power). Hydrogen addition increased the pattern factor and NOx emissions at the outlet of the combustion chamber.

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Marzouk, Osama A. "Adiabatic Flame Temperatures for Oxy-Methane, Oxy-Hydrogen, Air-Methane, and Air-Hydrogen Stoichiometric Combustion using the NASA CEARUN Tool, GRI-Mech 3.0 Reaction Mechanism, and Cantera Python Package". Engineering, Technology & Applied Science Research 13, nr 4 (9.08.2023): 11437–44. http://dx.doi.org/10.48084/etasr.6132.

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The Adiabatic Flame Temperature (AFT) in combustion represents the maximum attainable temperature at which the chemical energy in the reactant fuel is converted into sensible heat in combustion products without heat loss. AFT depends on the fuel, oxidizer, and chemical composition of the products. Computing AFT requires solving either a nonlinear equation or a larger minimization problem. This study obtained the AFTs for oxy-methane (methane and oxygen), oxy-hydrogen (hydrogen and oxygen), air-methane (methane and air), and air-hydrogen (hydrogen and air) for stoichiometric conditions. The reactant temperature was 298.15 K (25°C), and the pressure was kept constant at 1 atm. Two reaction mechanisms were attempted: a global single-step irreversible reaction for complete combustion and the GRI-Mech 3.0 elementary mechanism (53 species, 325 steps) for chemical equilibrium with its associated thermodynamic data. NASA CEARUN was the main modeling tool used. Two other tools were used for benchmarking: an Excel and a Cantera-Python implementation of GRI-Mech 3.0. The results showed that the AFTs for oxy-methane were 5,166.47 K (complete combustion) and 3,050.12 K (chemical equilibrium), and dropped to 2,326.35 K and 2,224.25 K for air-methane, respectively. The AFTs for oxy-hydrogen were 4,930.56 K (complete combustion) and 3,074.51 K (chemical equilibrium), and dropped to 2,520.33 K and 2,378.62 K for air-hydrogen, respectively. For eight combustion modeling cases, the relative deviation between the AFTs predicted by CEARUN and GRI-Mech 3.0 ranged from 0.064% to 3.503%.

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Azatyan, V. V., I. A. Bolodiyan, S. N. Kopilov, Yu N. Shebeko i V. I. Kalachev. "The Influence of Small Additives of Alcohol Vapors on Combustion of Hydrogen and Methane in Air". Eurasian Chemico-Technological Journal 6, nr 3 (13.07.2017): 171. http://dx.doi.org/10.18321/ectj608.

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The results of investigation of combustion of hydrogen-air and methane-air mixtures in the presence of small additives of ethanol, isopropanol, propenol in horizontal tubes are presented. The additives reduce the upper limits of flame propagation and the rate of flame propagation. The difference of inhibiting efficiencies<br />of these alcohols corresponds to their ability to break the reaction chains of hydrogen and methane combustion processes. In the mixtures, containing less than 15% of hydrogen the suppression of combustion does not occur.

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Ren, Shoujun, William P. Jones i Xiaohan Wang. "Hydrogen-enriched methane combustion in a swirl vortex-tube combustor". Fuel 334 (luty 2023): 126582. http://dx.doi.org/10.1016/j.fuel.2022.126582.

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Griebel, P., E. Boschek i P. Jansohn. "Lean Blowout Limits and NOx Emissions of Turbulent, Lean Premixed, Hydrogen-Enriched Methane/Air Flames at High Pressure". Journal of Engineering for Gas Turbines and Power 129, nr 2 (15.08.2006): 404–10. http://dx.doi.org/10.1115/1.2436568.

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Flame stability is a crucial issue in low NOx combustion systems operating at extremely lean conditions. Hydrogen enrichment seems to be a promising option to extend lean blowout limits (LBO) of natural gas combustion. This experimental study addresses flame stability enhancement and NOx reduction in turbulent, high-pressure, lean premixed methane/air flames in a generic combustor capable of a wide range of operating conditions. Lean blowout limits and NOx emissions are presented for pressures up to 14bar, bulk velocities in the range of 32–80m∕s, two different preheating temperatures (673K, 773K), and a range of fuel mixtures from pure methane to 20% H2∕80%CH4 by volume. The influence of turbulence on LBO limits is also discussed. In addition to the investigation of perfectly premixed H2-enriched flames, LBO and NOx are also discussed for hydrogen piloting. Experiments have revealed that a mixture of 20% hydrogen and 80% methane, by volume, can typically extend the lean blowout limit by ∼10% compared to pure methane. The flame temperature at LBO is ∼60K lower resulting in the reduction of NOx concentration by ≈35%(0.5→0.3ppm∕15%O2).

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Mohanasundaram, Kavin, i Nagarajan Govindan. "Effect of air preheating, exhaust gas recirculation and hydrogen enrichment on biodiesel/methane dual fuel engine". Thermal Science, nr 00 (2020): 146. http://dx.doi.org/10.2298/tsci191024146m.

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An experimental study was carried out to investigate the effect of intake air preheating, exhaust gas recirculation and hydrogen enrichment on performance, combustion and emission characteristics of Methane/waste cooking oil biodiesel fuelled compression ignition engine in dual fuel mode. Methyl ester derived from waste cooking oil was used as a pilot fuel which was directly injected into the combustion chamber at the end of the compression stroke. Methane/hydrogen-enriched methane was injected as the main fuel in the intake port during the suction stroke using a low pressure electronic port fuel injector which is controlled by an electronic control unit. The experiments were conducted at a constant speed and at the maximum load. Experimental results indicated that the increase in energy share of gaseous fuel extends the ignition delay. With air preheating the thermal efficiency increased to 49% and 55% of methane and hydrogen-enriched methane energy share respectively. Carbon monoxide and hydrocarbon emissions were higher in methane combustion with biodiesel when compared to the conventional diesel operation at full load and a reduction in carbon monoxide and hydrocarbon was observed with air preheating. Lower oxides of nitrogen were observed with gaseous fuel combustion and it further reduced with exhaust gas recirculation but oxides of nitrogen increased by preheating the intake air. Improvement in thermal efficiency with a reduction in hydrocarbon and carbon monoxide was observed with hydrogen-enriched methane.

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Karim, G. A., i G. Zhou. "The Uncatalyzed Partial Oxidation of Methane for the Production of Hydrogen With Recirculation". Journal of Energy Resources Technology 115, nr 4 (1.12.1993): 307–13. http://dx.doi.org/10.1115/1.2906437.

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The combustion of rich mixtures of methane representing natural gas in air or oxygenated air involving the uncatalyzed partial oxidation of methane is examined analytically with the view of hydrogen and/or synthesis gas (carbon monoxide and hydrogen) production from natural gas. This is carried out in turn for isothermal, constant pressure and constant volume combustion processes over the feed temperature range of 800–2000K and equivalence ratio of up to 3.5. The role of various operating parameters in establishing the yield of hydrogen is presented and discussed. The effectiveness of the controlled recirculation of combustion gases to the feed for enhancing the reaction and conversion rates of methane into hydrogen is examined. It is shown that there are some conditions that can be employed for such recirculation to yield significant increases in the conversion rate.

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Wang, Y., M. Y. Gu i L. Cao. "Soot formation in methane-ethylene binary fuel combustion with hydrogen addition". Journal of Physics: Conference Series 2208, nr 1 (1.03.2022): 012017. http://dx.doi.org/10.1088/1742-6596/2208/1/012017.

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Abstract A numerical investigation of soot formation was conducted by applying the reactive molecular dynamics, and the chemical effect of H2 addition on the soot formation was explored. It was found that a higher initial methane ratio under the same hydrogen doping ratio could accelerate the rate of methane consumption and hydrogen generation As the proportion of methane in the methane-ethylene binary fuel increased, the chemical effect of H2 on the carbon number of the largest soot particles gradually weakened. Quantitative analysis showed that there was almost no coupling effect of hydrogen addition in the methane-ethylene binary fuel.

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Makaryan, Iren A., Igor V. Sedov, Eugene A. Salgansky, Artem V. Arutyunov i Vladimir S. Arutyunov. "A Comprehensive Review on the Prospects of Using Hydrogen–Methane Blends: Challenges and Opportunities". Energies 15, nr 6 (20.03.2022): 2265. http://dx.doi.org/10.3390/en15062265.

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An analysis of the literature data indicates a wide front of research and development in the field of the use of methane–hydrogen mixtures as a promising environmentally friendly low-carbon fuel. The conclusion of most works shows that the use of methane–hydrogen mixtures in internal combustion engines improves their performance and emission characteristics. The most important aspect is the concentration of hydrogen in the fuel mixture, which affects the combustion process of the fuel and determines the optimal operating conditions of the engine. When using methane–hydrogen mixtures with low hydrogen content, the safety measures and risks are similar to those that exist when working with natural gas. Serious logistical problems are associated with the difficulties of using the existing gas distribution infrastructure for transporting methane–hydrogen mixtures. It is possible that, despite the need for huge investments, it will be necessary to create a new infrastructure for the production, storage and transportation of hydrogen and its mixtures with natural gas. Further research is needed on the compatibility of pipeline materials with hydrogen and methane–hydrogen mixtures, safety conditions for the operation of equipment operating with hydrogen or methane–hydrogen mixtures, as well as the economic and environmental feasibility of using these energy carriers.

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Cimino, S., C. Allouis, G. Mancino i R. Nigro. "Hybrid Catalytic Combustion of Methane/Hydrogen Mixtures". Combustion Science and Technology 186, nr 4-5 (23.04.2014): 552–62. http://dx.doi.org/10.1080/00102202.2014.883250.

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Zhao, Ke, Dawei Cui, Tongmo Xu, Qulan Zhou, Shien Hui i Hongli Hu. "Effects of hydrogen addition on methane combustion". Fuel Processing Technology 89, nr 11 (listopad 2008): 1142–47. http://dx.doi.org/10.1016/j.fuproc.2008.05.005.

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Mundhwa, Mayur, i Christopher P. Thurgood. "Improved performance of a catalytic plate reactor coated with distributed layers of reforming and combustion catalysts for hydrogen production". Reaction Chemistry & Engineering 3, nr 4 (2018): 487–514. http://dx.doi.org/10.1039/c8re00013a.

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Reale, Fabrizio, Raffaela Calabria, Fabio Chiariello, Rocco Pagliara i Patrizio Massoli. "A Micro Gas Turbine Fuelled by Methane-Hydrogen Blends". Applied Mechanics and Materials 232 (listopad 2012): 792–96. http://dx.doi.org/10.4028/www.scientific.net/amm.232.792.

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The combustion efficiency and the gaseous emission of a 100 kWe MGT, designed for working with natural gas but fuelled with blends containing up to 10% of hydrogen is investigated. A critical comparison between experimental data and results of the CFD analysis of the combustor is discussed. The k-epsilon RANS turbulence model and the Finite Rate – Eddy Dissipation combustion model were used in the numerical computations. The chemical kinetic mechanisms embedded were the 2-step Westbrook and Dryer for methane oxidation, 1-step Westbrook and Dryer for hydrogen oxidation and the Zeldovich mechanism for NO formation. The experimental data and numerical computations are in agreement within the experimental accuracy for NO emissions. Regarding CO, there is a significant deviation between experimental and computational data due to the scarce predictive capability of the simple two steps kinetic mechanism was adopted. From a practical point of view, the possibility of using fuels with a similar Wobbe index was confirmed. In particular the addiction of 10 % of hydrogen to pure methane doesn’t affect the behavior of the micro gas turbine either in terms of NO or CO emissions.

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Karim, G. A., i M. G. Kibrya. "Variations of the Lean Blowout Limits of a Homogeneous Methane-Air Stream in the Presence of a Metallic Wire Mesh". Journal of Engineering for Gas Turbines and Power 108, nr 3 (1.07.1986): 446–49. http://dx.doi.org/10.1115/1.3239927.

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The combustion of a homogeneous lean methane-air stream was investigated in a vertical, cylindrical combustor of 150 mm diameter in the presence of a metallic wire mesh. Eight metallic materials were deposited in turn onto a stainless steel wire mesh by electroplating. The potential improvement in the lean blowout limit due to catalytic effects was established separately from those due to the thermal and aerodynamic contributions of the wire mesh and its holder ring. The effectiveness of the various metallic surfaces tested in the lean combustion of methane was in the following descending order: Pt → Cu → Ag → brass → Cr → Cd → Ni → stainless steel. Moreover, it was confirmed that hydrogen was more sensitive to catalytic effects extending to relatively lower temperatures than methane.

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Matyunin, O. O., S. K. Arkhipov, A. A. Shilova, N. L. Bachev i R. V. Bulbovich. "Analysis of the combustion characteristics of hydrogen and hydrocarbon fuels based on the results of numerical simulation". Problems of the Regional Energetics, nr 3(55) (sierpień 2022): 54–67. http://dx.doi.org/10.52254/1857-0070.2022.3-55.05.

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At present, an upward trend in the field of studying the processes of hydrogen combustion in the combustion chambers of the ground-based gas turbine power plants is obvious. The use of pure hydrogen as a fuel gas would solve the problem of environmental decarbonization. One of the emerging problems is to ensure the stable combustion of such fuels in combustion chambers of various applications. The information-analytical review of studies showed that there is a large number of theoretical and experimental results on the diffusion and homogeneous combustion of hydrogen and hydrogen-containing fuels in various burners and combustion chambers, which are not part of the existing gas turbine power plants. The purpose of this work is a comparative analysis of the gas-dynamic and emission characteristics of the combustion of the hydrogen-air and methane-air components based on the results of numerical simulation of a convertible combustion chamber of a 75 kW microgas turbine power plant. This goal is achieved by numerical simulation of the diffusion combustion of hydrogen and methane with air in a convertible combustion chamber. The most significant result of the work is obtaining the isosurface of the flame, which made it possible to obtain the conditions for stable combustion in the form of the Damköhler criterion and the ratio of the midsection velocity to the velocity of turbulent combustion. The significance of the results obtained lies in the further development of the methodology for the conversion of megawatt-class gas turbine plants to hydrogen and hydrogencontaining fuels.

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Zhang, Yan, i Heqing Jiang. "A novel route to improve methane aromatization by using a simple composite catalyst". Chemical Communications 54, nr 73 (2018): 10343–46. http://dx.doi.org/10.1039/c8cc05059g.

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Grab-Rogaliński, Karol. "The influence of hydrogen addition for exhaust gas emission in SI gas engine". AUTOBUSY – Technika, Eksploatacja, Systemy Transportowe 20, nr 1-2 (28.02.2019): 241–45. http://dx.doi.org/10.24136/atest.2019.043.

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One of the major problems in internal combustion engines is emission of pollutants with exhaust gases. Those pollutants are not only harmful for environment but also for humans. To decrease emission of pollutants many mechanical and chemical methods are used in internal combustion engines especially in exhaust system such as TWC, DPF, SCR. Alternative way for decrease in exhaust gas pollutants is use of alternative fuel as a primary energy carrier or as an additional fuel for base hydrocarbon one. In this studies the hydrogen was used as a additional fuel to methane. Both fuels were delivered to intake manifold. The share of the fuel was 100/0 methane/hydrogen and 70/30 methane/hydrogen. The addition of hydrogen to base fuel shown decrease of exhaust pollutants from engine and increase in engine operating parameters.

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Bai, Xiao Lei, Anna Zheng, Na Sun, Hong Guang Zhang i Xue Jiao Han. "Effect of Hydrogen Addition into Methane-Air Mixture on Combustion Pressure". Advanced Materials Research 433-440 (styczeń 2012): 166–71. http://dx.doi.org/10.4028/www.scientific.net/amr.433-440.166.

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To get the effect of hydrogen addition under different initial pressures, different initial temperatures and different initial equivalence ratios on combustion pressure, relevant tests of methane-hydrogen-air mixture have been carried out in constant volume combustion bomb. The results showed that higher initial temperature and lower initial pressure is helpful to get higher flame propagation velocity while other initial conditions keep invariable; as hydrogen blend ratio increases, both maximum combustion pressure and maximum rate of pressure rise increase, with the appearance time obviously earlier and cycle-to-cycle variation obviously lower.

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Karmann, Stephan, Stefan Eicheldinger, Maximilian Prager i Georg Wachtmeister. "Optical and thermodynamic investigations of a methane and hydrogen blend fueled large bore engine". International Journal of Engine Research 23, nr 5 (3.01.2022): 846–64. http://dx.doi.org/10.1177/14680874211066735.

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The following paper presents thermodynamic and optical investigations of the natural flame and OH radical chemiluminescence of a hydrogen enriched methane combustion compared to natural gas combustion. The engine under investigation is a port-fueled unscavenged prechamber 4.8 L single cylinder large bore engine. The blends under consideration are 2%V, 5%V,10%V, and 40%V of hydrogen expected to be blended within existing natural gas grids in a short and mid-term timeline in order to store green energy from solar and wind. These fuel blends could be used for stabilization of the energy supply by reconverting the renewable fuel CH4/H2 in combined heat and power plants. As expected, admixture of hydrogen extends the ignition limits of the fuel mixture toward lean ranges up to an air-fuel equivalence ratio of almost 2. No negative effect on combustion is observed up to an admixture of 40%V hydrogen. At 40%V hydrogen, abnormal combustion like backfire occurs at an air-fuel equivalence ratio of 1.5. The higher mixtures exhibit increased nitrogen oxide emissions due to higher combustion chamber temperatures, while methane slip and CO emissions are reduced due to more complete combustion. The optical investigation of the natural flame and OH radical chemiluminescence are in good agreement with the thermodynamic results verifying the more intense combustion of the fuel blends by means of the chemiluminescence intensity. Further, lube oil combustion and a continuing luminescence after the thermodynamic end of combustion are observed.

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Mihăescu, Lucian, Dorin Stanciu, Gheorghe Lăzăroiu, Ionel Pîșă i Gabriel Negreanu. "Comparative analysis between methane and hydrogen regarding ignition and combustion in diffusive mode". E3S Web of Conferences 327 (2021): 01001. http://dx.doi.org/10.1051/e3sconf/202132701001.

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The hydrogen is expected to become the energy vector of the future. If for environmental protection this concept it is obvious, the data for the design of hydrogen combustion facilities are still insufficient. This paper discusses the fundamental actions related to the design of a hydrogen burner. Numerical modelling researches using the Ansys-Fluent software has shown the link between the flow velocity in combustible gas jets together with the required air and the combustion rates. Combustion models (both analytical and numerical) allowed finding the optimal ratios between the two specified velocities (combustion and flow) compared to those for methane combustion, correlated also with the classical directions and recommendations for the burner design.

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Mrakin, Anton N., Olga V. Afanaseva i Oleg Yu Kuleshov. "CALCULATION OF HEAT TRANSFER INTENSITY OF GAS FUEL COMBUSTION PRODUCTS". Bulletin of the Tomsk Polytechnic University Geo Assets Engineering 334, nr 5 (31.05.2023): 109–15. http://dx.doi.org/10.18799/24131830/2023/5/3987.

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Link for citation: Mrakin A.N., Afanaseva O.V., Kuleshov O.Yu. Calculation of heat transfer intensity of gas fuel combustion products. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 5, рр.109-115. The relevance of the research is determined by the modern trend in the field of thermal power engineering and heat engineering for the transition from traditional gaseous fuel (methane) to the use of hydrogen, methane-hydrogen mixtures, as well as thermochemical conversion gases. Switching to new non-design fuel is justified by considerations of reducing the negative impact on the environment and increasing the thermal efficiency of fuel combustion plants. In this case, the use of fuels with a composition different from the design one will affect the heat transfer processes. The main aim: carrying out a comparative analysis of indicators of the intensity of radiant and convective heat transfer of combustion products of non-design fuels, such as hydrogen, methane-hydrogen mixture and thermochemical conversion gases. As an assumption in the formulation of the problem and objectives of the study, the constancy of the heat release power in the apparatus due to changes in the amount of fuel burned was taken. Objects: heat exchange surface of a fire-tube hot water boiler. Methods: carrying out numerical calculation using traditional approaches to determine the indicators of the intensity of heat transfer in the system «combustion products – metal wall of the pipe of thermal power plants». We also used the relations tested earlier by other authors to calculate the thermophysical parameters of gas mixtures. Results. According to the results of the performed comparative calculations, we can conclude that the transition from the use of conventional fuel (natural gas/methane) to its thermochemical conversion gases under the considered conditions has almost no effect on the integral heat transfer performance. To a greater extent, this transition is caused by changes in the intensity of heat transfer for products of combustion of hydrogen and methane-hydrogen mixture, which will affect the operation of thermal power and heat technological installations. At the same time, it is necessary to conduct additional research on the combustion kinetics of thermochemical methane conversion gases, their thermophysical properties, etc., because the hardware design, type of the catalyst used and operating parameters of the process will affect the composition of obtained synthesis gas.

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Davidy, Alon. "Multiphysics Design of Pet-Coke Burner and Hydrogen Production by Applying Methane Steam Reforming System". Clean Technologies 3, nr 1 (17.03.2021): 260–87. http://dx.doi.org/10.3390/cleantechnol3010015.

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Pet-coke (petroleum coke) is identified as a carbon-rich and black-colored solid. Despite the environmental risks posed by the exploitation of pet-coke, it is mostly applied as a boiling and combusting fuel in power generation, and cement production plants. It is considered as a promising replacement for coal power plants because of its higher heating value, carbon content, and low ash. A computational fluid dynamics (CFD) computational model of methane steam reforming was developed in this research. The hydrogen production system is composed from a pet-coke burner and a catalyst bed reactor. The heat released, produced by the pet-coke combustion, was utilized for convective and radiative heating of the catalyst bed for maintaining the steam reforming reaction of methane into hydrogen and carbon monoxide. This computational algorithm is composed of three steps—simulation of pet-coke combustion by using fire dynamics simulator (FDS) software coupled with thermal structural analysis of the burner lining and a multiphysics computation of the methane steam reforming (MSR) process taking place inside the catalyst bed. The structural analysis of the burner lining was carried out by coupling the solutions of heat conduction equation, Darcy porous media steam flow equation, and structural mechanics equation. In order to validate the gaseous temperature and carbon monoxide mole fraction obtained by FDS calculation, a comparison was carried out with the literature results. The maximal temperature obtained from the combustion simulation was about 1440 °C. The calculated temperature is similar to the temperature reported, which is also close to 1400 °C. The maximal carbon dioxide mole fraction reading was 15.0%. COMSOL multi-physics software solves simultaneously the catalyst media fluid flow, heat, and mass with chemical reaction kinetics transport equations of the methane steam reforming catalyst bed reactor. The methane conversion is about 27%. The steam and the methane decay along the catalyst bed reactor at the same slope. Similar values have been reported in the literature for MSR temperature of 510 °C. The hydrogen mass fraction was increased by 98.4%.

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Vetkin, A. V., A. L. Suris i O. A. Litvinova. "Investigation of combustion characteristics of methane-hydrogen fuels". Thermal Engineering 62, nr 1 (17.12.2014): 64–67. http://dx.doi.org/10.1134/s0040601515010115.

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Lee, Joo H., D. L. Trimm i N. W. Cant. "The catalytic combustion of methane and hydrogen sulphide". Catalysis Today 47, nr 1-4 (styczeń 1999): 353–57. http://dx.doi.org/10.1016/s0920-5861(98)00317-4.

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Deutschmann, O., L. I. Maier, U. Riedel, A. H. Stroemman i R. W. Dibble. "Hydrogen assisted catalytic combustion of methane on platinum". Catalysis Today 59, nr 1-2 (czerwiec 2000): 141–50. http://dx.doi.org/10.1016/s0920-5861(00)00279-0.

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Scarpa, Andrea, Paola Sabrina Barbato, Gianluca Landi, Raffaele Pirone i Gennaro Russo. "Combustion of methane–hydrogen mixtures on catalytic tablets". Chemical Engineering Journal 154, nr 1-3 (listopad 2009): 315–24. http://dx.doi.org/10.1016/j.cej.2009.05.013.

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Ting, David S. K., i Graham T. Reader. "Hydrogen peroxide for improving premixed methane–air combustion". Energy 30, nr 2-4 (luty 2005): 313–22. http://dx.doi.org/10.1016/j.energy.2004.04.039.

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Gurakov, N. I., O. V. Kolomzarov, D. V. Idrisov, A. D. Popov, A. A. Litarova, A. S. Semenikhin, A. A. Kuznetsova i S. S. Matveev. "Stability Limits of the Methane–Hydrogen Mixture Combustion". Bulletin of the Lebedev Physics Institute 50, nr 4 (kwiecień 2023): 150–57. http://dx.doi.org/10.3103/s1068335623040061.

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Li, Risheng, i Hajime Kawanami. "A Recent Review of Primary Hydrogen Carriers, Hydrogen Production Methods, and Applications". Catalysts 13, nr 3 (10.03.2023): 562. http://dx.doi.org/10.3390/catal13030562.

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Hydrogen is a promising energy carrier, especially for transportation, owing to its unique physical and chemical properties. Moreover, the combustion of hydrogen gas generates only pure water; thus, its wide utilization can positively affect human society to achieve global net zero CO2 emissions by 2050. This review summarizes the characteristics of the primary hydrogen carriers, such as water, methane, methanol, ammonia, and formic acid, and their corresponding hydrogen production methods. Additionally, state-of-the-art studies and hydrogen energy applications in recent years are also included in this review. In addition, in the conclusion section, we summarize the advantages and disadvantages of hydrogen carriers and hydrogen production techniques and suggest the challenging tasks for future research.

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Tambovtsev, A. S., V. V. Kozlov, M. V. Litvinenko, Yu A. Litvinenko i A. G. Shmakov. "A study and comparison of the modes of diffusion combustion of hydrogen and methane at their outflow from the annular nozzle together with the flow of supplied air from the coaxially located circular nozzle". Journal of Physics: Conference Series 2119, nr 1 (1.12.2021): 012035. http://dx.doi.org/10.1088/1742-6596/2119/1/012035.

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Abstract The article presents qualitative data on the study of the process of diffusion combustion during the outflow of a gas jet from a nozzle apparatus with a certain arrangement of nozzles. The nozzle apparatus is a round nozzle with a straight channel and a coaxially located annular slot. In the experiments, hydrogen or methane was supplied through an annular slot, and the air was supplied through a central circular micro nozzle. The main features of the diffusion combustion of hydrogen and methane during the outflow from the nozzle apparatus are revealed and a qualitative comparison of the processes is carried out. In both cases, at the initial stage, laminar combustion is observed near the nozzle exit and a breakthrough of the flame front occurs with the release of an incombustible mixture of combustible gas and air. At a high flow rate, the flame separates from the nozzle exit. The fundamental difference is that hydrogen exhibits significantly better combustion stabilization characteristics at the nozzle exit.

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Ambrozik, Andrzej, Tomasz Ambrozik, Dariusz Kurczyński, Piotr Łagowski i Edward Trzensik. "Cylinder Pressure Patterns in the SI Engine Fuelled by Methane and by Methane and Hydrogen Blends". Solid State Phenomena 210 (październik 2013): 40–49. http://dx.doi.org/10.4028/www.scientific.net/ssp.210.40.

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nternal combustion engine has been in existence for a long time, but it is still in the scope of research interests and is contained in the subject matter of numerous development studies and analyses. The paper presents basic goals of research into combustion engines. A short characteristics of piston combustion engine as an object of control and adjustment was provided. It was indicated that measurements of the working medium cylinder pressure patterns could be applied to control the performance of the engine, especially the multi-fuel one. The paper presents the results of measurements of the working medium pressure patterns in the cylinder of 1.6 dm3X16SZR engine of Opel Astra car, which was fuelled by petrol, methane, and also by methane and hydrogen blends. Substantial differences in the cylinder pressure patterns were found for the engine running on alternative fuels and on conventional fuel. An increase in the hydrogen content in the blend resulted in an increase in the maximum pressures in the engine cylinder and improvements of indicated parameters when compared with the parameters determined for the engine fuelled by pure methane.

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Taymarov, M. A., R. V. Akhmetova, Ye G. Chiklyayev, Y. V. Lavirko, E. A. Akhmetov i A. O. Garifullina. "Study of the speed of flame distribution in the combustion of methane-hydrogen fractions". E3S Web of Conferences 124 (2019): 05065. http://dx.doi.org/10.1051/e3sconf/201912405065.

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At present, natural gas of the Urengoyskoye field is burned in boilers of thermal power plants (TPP) to generate electricity. At the same time, refineries and petrochemical plants deepen the processing of fossil liquid hydrocarbons. The final product of processing is not only motor fuels, ethylene glycols, plastics, accompanying inert gases such as argon, but also a large amount of combustible secondary gaseous mixtures of the methane series. These mixtures contain a wide array of combustible components. Among them there is the methane-hydrogen fraction, which is characterized by a fairly high hydrogen content. A distinctive feature of the use of hydrogen as a fuel is the high rate of flame propagation and the relatively low heat of combustion [1, p.6-8]. The methane-hydrogen fraction due to the volatility of the composition and a wide range of changes in the heat of combustion was recently used in refineries for their own needs as an insignificant additive to combusted natural gas in process furnaces [2-5]. If the methane-hydrogen fraction was not utilized as a fuel in these furnaces, it was burned in flares. Due to the increase in oil refining volumes and the increase in the amount of methane-hydrogen fraction produced, it became realistic to use this gaseous fraction as the main fuel for power boilers of thermal power plants located near petrochemical plants. In the near future, it is planned to use the methane-hydrogen fraction as an additive to the natural gas for 20 power steam boilers of the Nizhnekamsk CHP-1 with a total thermal capacity of 6000 MW. The supplier of the methane-hydrogen fraction is the TAIF NK oil refineries. Depending on the technology of oil refining, the hydrogen content in the methane-hydrogen fraction ranges from 10 to 27% (by weight). The concentration limits of hydrogen ignition in a mixture with air have been experimentally studied by many researchers [6–8] mainly during bench testing or inside laboratories. A feature of the oxidation of hydrogen by air oxygen is the fact that there is a difference between the spread of the flame in limited volumes and in large volumes of the furnace space of energy boilers [9]. In small volumes, when the flame front collides with the wall, oxidation reactions are interrupted, and this does not occur in large volumes. Therefore, the study of flame propagation speed and concentration limits of ignition of methanehydrogen fractions mixed with air in relation to the conditions of furnace volumes of power boilers is relevant. In this work using the in-house software [2-5] calculations were made to determine the burning rate for various compositions of mixtures of methane-hydrogen fractions (MHF) with Urengoi natural gas. It was found that the flame propagation rate of the MHF, compared with hydrogen (see Table 2), decreases 1.76 times. For a mixture of the MHF with Urengoi gas with thermal fractions of the MHF of 12% and 25%, the flame propagation rate increases, respectively, 1.4 times and 1.78 times compared with burning pure Urengoi gas.

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Nam, Jaehyun, Younghun Lee i Jai-ick Yoh. "LES Analysis on Combustion Characteristics of a Hydrogen/ Methane Gas Turbine Combustor". Journal of the Korean Society for Aeronautical & Space Sciences 48, nr 8 (31.08.2020): 589–95. http://dx.doi.org/10.5139/jksas.2020.48.8.589.

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Yasiry, Ahmed, Jinhua Wang, Longkai Zhang, Hongchao Dai, Ahmed A. A. Abdulraheem, Haroun A. K. Shahad i Zuohua Huang. "Experimental Study on the Effect of Hydrogen Addition on the Laminar Burning Velocity of Methane/Ammonia–Air Flames". Applied Sciences 13, nr 10 (9.05.2023): 5853. http://dx.doi.org/10.3390/app13105853.

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Variations in methane–ammonia blends with hydrogen enrichment can modify premixed flame behavior and play a crucial role in achieving ultra-low carbon emissions and sustainable energy consumption. Current combustion units may co-fire ammonia/methane/hydrogen, necessitating further investigation into flame characteristics to understand the behavior of multi-component fuels. This research aims to explore the potential of replacing natural gas with ammonia while making only minor adjustments to equipment and processes. The laminar burning velocity (LBV) of binary blends, such as ammonia–methane, ammonia–hydrogen, and hydrogen–methane–air mixtures, was investigated at an equivalence ratio of 0.8–1.2, within a constant volume combustion chamber at a pressure of 0.1 MPa and temperature of 298 K. Additionally, tertiary fuels were examined with varying hydrogen blending ratios ranging from 0% to 40%. The results show that the laminar burning velocity (LBV) increases as the hydrogen fraction increases for all mixtures, while methane increases the LBV during blending with ammonia. Hydrogen-ammonia blends are the most effective mixture for increasing LBV non-linearly. Enhancement parameters demonstrate the effect of ternary fuel, which behaves similarly to equivalent methane in terms of adiabatic flame temperature and LBV achieved at 40% hydrogen. Experimental data for neat and binary mixtures were validated by different kinetics models, which also showed good consistency. The ternary fuel mixtures were also validated with these models. The Li model may qualitatively predict well for ammonia-dominated fuel. The Shrestha model may overestimate results on the rich side due to the incomplete N2Hisub-mechanism, while lean and stoichiometric conditions have better predictions. The Okafor model is always overestimated.

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Szunyog, István, i Anna Bella Galyas. "REDUCTION OF POLLUTANTS IN THE RESIDENTIAL SECTOR BY MIXING HYDROGEN INTO THE NATURAL GAS NETWORK IN HUNGARY". Acta Tecnología 6, nr 4 (31.12.2020): 111–17. http://dx.doi.org/10.22306/atec.v6i4.94.

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According to some forecasts, hydrogen will play a significant role throughout the world by 2030 as an energy source, the biggest benefits of which include not only being able to come from renewable sources, but thus storing the energy produced, which is not currently solved. The combustion of hydrogen does not produce CO2, only negligible amounts of combustion air, unlike methane. This will reduce GHG emissions associated with end-user equipment. In this article, the authors examine the amount of hydrogen that can be fed into the Hungarian natural gas network in accordance with the current gas quality standard, and then carry out a comparative analysis of the methane, the main component that makes up hydrogen and natural gas. The authors will study the exact effect of hydrogen content on natural gas-regulated devices and estimate the theoretical CO2 emissions available in the Hungarian residential sector at different rates of hydrogen.

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Reale, Fabrizio. "Effects of Steam Injection on the Permissible Hydrogen Content and Gaseous Emissions in a Micro Gas Turbine Supplied by a Mixture of CH4 and H2: A CFD Analysis". Energies 15, nr 8 (15.04.2022): 2914. http://dx.doi.org/10.3390/en15082914.

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The use of hydrogen in small scale gas turbines is currently limited by several issues. Blending hydrogen with methane or other gaseous fuels can be considered a low medium-term viable solution, with the goal of reducing greenhouse gas emissions. In fact, only small amounts can be mixed with methane in premixed combustors, due to the risk of flashback. The aim of this article is to investigate the injection of small quantities of steam as a method of increasing the maximum permissible hydrogen content in a mixture with methane. The proposed approach involves introducing the steam directly into the combustion chamber into the main fuel feeding system of a Turbec T100. The study is carried out by means of CFD analysis of the combustion process. A thermodynamic analysis of the energy system is used to determine boundary conditions. The combustion chamber is discretized using a three-dimensional mesh consisting of 4.7 million nodes and the RANS RSM model is used to simulate the effects of turbulence. The results show that the addition of steam may triple the permissible percentage of hydrogen in the mixture for the considered MGT, passing from 10% to over 30% by volume, also leading to a reduction in NOx emissions without a significant variation in CO emissions.

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Malenkov, A. S., D. M. Kharlamova, V. Yu Naumov i T. P. Karev. "Features of methane-hydrogen mixtures combustion in oxy-fuel power cycle combustion chamber". IOP Conference Series: Earth and Environmental Science 1045, nr 1 (1.06.2022): 012143. http://dx.doi.org/10.1088/1755-1315/1045/1/012143.

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Abstract The paper is focused on the study of features of methane-hydrogen mixtures combustion in an oxy-fuel power cycle combustion chamber. The goal of the study is to find optimal combinations of thermodynamic parameters, allowing to bring the fundamental combustion characteristics, such as the normal flame propagation rate, the adiabatic combustion temperature, and the ignition delay time, closer to the parameters that are characteristic of traditional gas turbine plants. The research method includes digital experiments in the Chemkin-Pro software package using detailed kinetic patterns. The key features of the fuel combustion process in oxy-fuel power cycle combustion chambers are changing the diluent medium from atmospheric nitrogen to carbon dioxide, which is the working medium in the cycle, and applying a supercritical pressure (about 300 atm). Both changes negatively affect the combustion process intensity. To achieve the normal flame propagation rate and the maximum adiabatic temperature that are acceptable for the possible flame stabilization in the combustion zone, to exclude uneven heat release and large values of chemical underburning, the amount of CO2 diluent in the combustion zone shall be within the range of 10 to 20 % of the total amount of CO2 supplied to the combustion chamber.

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Ma, P. Y., Zhi Guo Tang, Y. L. Li, C. H. Nie, X. Z. He i Q. Z. Lin. "Conversion of Natural Gas to Hydrogen under Super Adiabatic Rich Combustion". Advanced Materials Research 105-106 (kwiecień 2010): 701–5. http://dx.doi.org/10.4028/www.scientific.net/amr.105-106.701.

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Interest in fuel cells in recent years has promoted the development of hydrogen sources. Methane (the main composition of natural gas) is an optimal fuel for hydrogen production due to its rich resource and its high ratio of hydrogen to carbon. In this work, several hydrogen processes, such as steam reforming of methane, partial oxidation, and auto thermal reforming, were reviewed. Different processes exhibit different importance for hydrogen production due to their diversity on usages. In this paper the special method of natural hydrogen production from natural gas with super adiabatic rich combustion is depicted in details. Some problems of this method were analyzed and discussed. In view of the existing problems, a new method was developed to be used for conversion of natural gas to hydrogen. The method can solve the problems of flame drift, heat preservation, product cooling, and low transform efficiency. Due to its simple and compact structure, it is attractive for distributing hydrogen production system and solving the transportation and storage problems of hydrogen.

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Deng, Bo Yuan, Yanghong Wei, Shao Peng Zhu i Xueke Che. "Effect of dielectric barrier discharge methane reforming products on the combustion performance of rocket engine". Journal of Physics: Conference Series 2551, nr 1 (1.07.2023): 012030. http://dx.doi.org/10.1088/1742-6596/2551/1/012030.

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Abstract Although the low-thrust liquid oxygen/methane rocket engine has broad application prospects, the low flame propagation speed and low combustion rate of methane fuel make the liquid oxygen/methane engine still face key technical challenges. Methane fuel is partially converted into hydrogen and ethane with higher combustion rate before being injected into the combustion chamber, which is positive for the use of dielectric barrier to improve the combustion performance of the engine. Therefore, this paper studies the effect of the main four products of dielectric barrier discharge reforming with methane conversion rate of 10%, on the flow field of the combustion chamber. The results show that the addition of reforming products can effectively improve the combustion efficiency of the engine. H2 in the reforming product can also improve the specific impulse performance of the engine by increasing the total pressure of the engine chamber. C2H4 will not affect the maximum temperature of the engine, However, it can expand the medium-high temperature range of engine temperature to different degrees. The addition of H2 accelerates the oxygen consumption rate, which provides a feasible way to reduce the design size of the engine and improve the combustion efficiency of the low-thrust engine.

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Vu, Tran Manh, Jeong Park, Jeong Soo Kim, Oh Boong Kwon, Jin Han Yun i Sang In Keel. "Experimental Study in H₂/CO/CH₄–Air and H₂/CO/C₃H₈–Air Premixed Flames. Part 2: Cellular Instabilities". Materials Science Forum 673 (styczeń 2011): 71–76. http://dx.doi.org/10.4028/www.scientific.net/msf.673.71.

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Experiments in a constant pressure combustion chamber at room temperature and elevated pressures using schlieren system were conducted to investigate the cellular instabilities in hydrogen/carbon monoxide/methane (or propane)–air premixed flames. In the present study, hydrodynamic and diffusional-thermal instabilities were evaluated to elucidate their effects to flame instabilities. Effective Lewis numbers of premixed flames with methane addition decrease for all of the cases. Meanwhile, the effective Lewis numbers with propane addition increase for lean and stoichiometric conditions, but they increase for rich and stoichiometric cases for hydrogen-enriched flames. With propane addition, the propensity for cells formation is significantly diminished whereas the cellular instabilities for hydrogen enriched flames are promoted. With methane addition, the similar behavior of cellularity is obtained, indicating that methane is not a candidate for suppressing cells formation in hydrogen/carbon monoxide/methane–air premixed flames.

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Marchenko, G. S., i Anatolii Smikhula. "FEATURES OF COMBUSTION OF HYDROGEN AND ITS MIXTURES WITH METHANE (OR NATURAL GAS) IN BOILERS AND FURNACES". International Journal of Energy for a Clean Environment 24, nr 5 (2023): 93–108. http://dx.doi.org/10.1615/interjenercleanenv.v24.i5.60.

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In the work the possibility and principles of partial or complete replacement of natural gas as a fuel with hydrogen and its mixtures with methane (or natural gas) in new and existing boilers and furnaces with a capacity of approximately 0.3-60 MWare determined. The performed calculation showed the possibility of using one diffusion burner on natural gas, hydrogen, or their mixture in any proportion and the thermal power of the burner on methane (or natural gas) and hydrogen or their mixture at the same gas pressure is close. The use of condensing boilers is preferable due to the greater amount of thermal energy (as a percentage of heat output in firebox) that is obtained by condensing water vapor from flue gases when burning hydrogen compared to burning methane (or natural gas) is showed. Some constructions of burners and boilers for burning hydrogen and its mixtures with methane (or natural gas) are proposed. The difference in specific losses during hydrogen transportation by gas pipelines for methane (or natural gas) are determined; when pure hydrogen was supplied into gas pipelines for natural gas, its leakage per unit time (m<sup>3</sup>/s) will be near 2.8 times higher, but the amount of energy lost will be less by approximately 9.2%.

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Li, Zehuan, Yulong Duan, Shilin Lei, Ziyang Wen, Lulu Zheng i Fengying Long. "Flame propagation of premixed gas explosion with different equivalent ratio under corrugated fire-retardant core". Thermal Science, nr 00 (2023): 146. http://dx.doi.org/10.2298/tsci230327146l.

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Based on the self-built experimental setup, the propagation law of explosion flame of hydrogen/methane premixed gas with different hydrogen volume fractions in different equivalent ratios was investigated under the action of a corrugated fire-retardant core. The experimental study shows that the flame isolation and suppression effect of the corrugated fire-retardant core at different equivalence ratios is either promoted or suppressed, the hydrogen/methane premixed gas explosion flame is quenched without hydrogen mixing when ?=0.8and1.0, and also quenched when ?=1.2indifferent hydrogen volume fractions. The corrugated flame-retardant core significantly affected the extinguishing of the explosion flame of the premixed gas when ?=1.2, the flame propagation speed and overpressure showed a similar trend under different volume fractions of hydrogen. When the flame is quenched, the flame is depressed inward to form a reverse spherical cell flame, reverse diffusion combustion phenomen on occurs, and it lasts a long time, eventually, the combustion reaction extinguished. The flame penetrated the corrugated fire-retardant core during the rest of conditions. When ?=1.0, the flame reaction of the hydrogen/methane premixed gas explosion under the action of the corrugated fire-retardant core is the most violent, and its propagation speed and overpressure jump rapidly until it reaches a peak.

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Karmann, Stephan, Stefan Eicheldinger, Maximilian Prager, Malte Jaensch i Georg Wachtmeister. "Optical and Thermodynamic Investigations of a Methane- and Hydrogen-Blend-Fueled Large-Bore Engine Using a Fisheye Optical System". Energies 16, nr 4 (5.02.2023): 1590. http://dx.doi.org/10.3390/en16041590.

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The following paper presents thermodynamic and optical investigations of hydrogen-enriched methane combustion, showing the potential of a hydrogen admixture as a means to decarbonize stationary power generation. The optical investigations are carried out through a fisheye optical system directly mounted into the combustion chamber, replacing one exhaust valve. All of the tests were carried out with constant fuel energy producing 16 bar indicated mean effective pressure. The engine under investigation is a port-fueled 4.8 l single-cylinder large-bore research engine. The test series compared the differences between a conventional spark plug and an unscavenged pre-chamber spark plug as an ignition system. The fuel blends under investigation are 5 and 10%V hydrogen mixed with methane and pure natural gas acting as a reference fuel. The thermodynamic results show a beneficial influence of the hydrogen admixture on both ignition systems and for all variations concerning the lean running limit, combustion stability and indicated efficiency, with the most significant influence being visible for the tests using conventional spark plugs. With the unscavenged pre-chamber spark plug and the combustion of the 10%V hydrogen admixture, an increase in the indicated efficiency of 0.8% compared to NG is achievable. The natural chemiluminescence intensity traces were observed to be predominantly influenced by the air–fuel equivalence ratio. This results in a 20% higher intensity for the unscavenged pre-chamber spark plug for the combustion of 10%V hydrogen compared to the conventional spark plug. This is also visible in the evaluations of the flame color derived from the dewarped combustion image series. The investigation of the torch flames also shows a difference in the air–fuel equivalence ratio but not between the different fuels. The results encourage the development of hydrogen-based fuels and the potential to store surplus sustainable energy in the form of hydrogen in existing gas grids.

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Mardani, Amir, i Hamed Karimi Motaalegh Mahalegi. "Hydrogen enrichment of methane and syngas for MILD combustion". International Journal of Hydrogen Energy 44, nr 18 (kwiecień 2019): 9423–37. http://dx.doi.org/10.1016/j.ijhydene.2019.02.072.

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