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Artykuły w czasopismach na temat "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.
Pełny tekst źródłaRozprawy doktorskie na temat "Hydrogen methane combustion"
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Gersen, Sander. "Experimental study of the combustion properties of methane/hydrogen mixtures". [S.l. : Groningen : s.n. ; University Library of Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/30528004X.
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Oztarlik, Gorkem. "Numerical and experimental investigations of combustion instabilities of swirled premixed methane-air flames with hydrogen addition". Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0076.
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Dans ce travail, les flammes stabilisées par tourbillonnement, assistées par hydrogène (enrichissement en hydrogène et pilotage) sont étudiées expérimentalement via l'expérience MIRADAS. Tout d'abord, les caractéristiques de stabilité statique, telles que les longueurs de flamme et les caractéristiques d'attachement de la flamme sont étudiées via des images de chimiluminescence CH * de flamme et les cas avec pilotage à l'hydrogène, pilotage au méthane et enrichissement en hydrogène sont comparés au cas de référence; d'une combustion méthane-air parfaitement prémélangée, pour une large gamme des richesse et des vitesses. On constate que le pilotage de l'hydrogène est la méthode la plus efficace pour fixer les flammes et étendre les plages de fonctionnement stables de la chambre de combustion. Ensuite, les caractéristiques de stabilité dynamique de l'installation sont étudiées expérimentalement via des cartes de stabilité et il est démontré que l'injection d'une très petite partie de la puissance thermique de l'hydrogène se traduit par un système plus stable ; une extension des points de fonctionnement stables dans les cartes de stabilité, ce qui signifie un fonctionnement global plus sûr. L'enrichissement en hydrogène et le pilotage du méthane sont également explorés et il est démontré que ces méthodes ne sont pas efficaces pour changer les cartes de stabilité, les cartes de stabilité ne sont pas effectuées. Par la suite, les réponses des flammes forcées sont étudiées expérimentalement et il est démontré que le pilotage de l'hydrogène et l'enrichissement en hydrogène provoquent une baisse du délai global de la fonction de transfert de flamme. Avec le pilotage de l'hydrogène, il y a une baisse globale du gain de la fonction de transfert de flamme, mais pour les cas enrichis en hydrogène, le gain est augmenté. Pour les cas pilotés au méthane, il y a une réduction globale du gain de la fonction de transfert de flamme, mais le délai n'est pas affectée. Par conséquent, pour explorer pourquoi et comment la fonction globale de transfert de flamme est modifiée avec différentes stratégies d'injection, des images de flamme forcée sont étudiées. Il est démontré que les changements dans la fonction de transfert de flamme sont causés par le comportement de compétition entre les réponses locales de dégagement de chaleur pour les cas pilotés par l'hydrogène. Autrement dit, il y a une différence de phase entre les réponses locales près du tube d'injection et les bords de la flamme, provoquant un effet de baisse, qui à son tour provoque une baisse du gain de la fonction de transfert de flamme. Ensuite, l'effet de différentes stratégies d'injection sur les émissions de polluants est étudié. Il est démontré que l'ajout d'hydrogène, en configuration d'injection pilote ou d'enrichissement d'hydrogène, entraîne une baisse des émissions de\mathrm{CO_2}pour la même puissance thermique. Les stratégies de pilotage provoquent une légère augmentation des émissions de NOx, mais les résultats montrent qu'une optimisation est possible pour obtenir des flammes stables, à faible \mathrm{CO_2} et à faible NOx. Enfin, les calculs LES et leurs comparaisons avec les résultats expérimentaux sont présentés. La capacité des calculs LES à prédire les réponses de la flamme est affichée et il est démontré que les réponses de la flamme proviennent des interactions des tourbillons qui se forment à la suite des pulsations acoustiques et des flammes. Des flammes sont enroulées autour de ces tourbillons, ce qui augmente la surface de la flamme. Plus loin dans le cycle de forçage, les parties enroulées des flammes commencent à toucher les parois de la chambre de combustion et s'éteignent, ce qui entraîne une perte de surface de la flamme. Ces changements dans la surface de la flamme se traduisent par un taux de dégagement de chaleur fluctuant, consistant en la réponse de la flammeIn this work, hydrogen assisted (hydrogen enrichment and piloting) swirl stabilized flames are studied experimentally via MIRADAS experiment. First of all, static stability characteristics, such as flame lengths and flame attachment characteristics are studied via CH* chemiluminescence flame images and cases with hydrogen piloting, methane piloting and hydrogen enrichment are compared to the reference case of perfectly premixed methane-air combustion for a wide range of equivalence ratios and bulk velocities. It is found out that hydrogen piloting is the most efficient method to attach the flames and extend operating ranges of the combustion chamber. Next the dynamic stability characteristics of the setup is studied experimentally via stability maps and it is shown that injection of a very small portion of the thermal power worth of hydrogen results in a more stable system and an extension in the stable operating points in the stability maps, meaning safer overall operation. Hydrogen enrichment and methane piloting are also explored, and it is demonstrated that these methods are not effective in changing stability maps, stability maps are not effected. Subsequently, the forced flame responses are studied experimentally and it is shown that hydrogen piloting and hydrogen enrichment causes a drop in the global time delay of the flame transfer function. With hydrogen piloting, there is a global drop in the flame transfer function gain, however for hydrogen enriched cases, the gain is increased. For methane piloted cases, there is a global reduction in the flame transfer function gain, however the time delay is not affected. Consequently, to explore why and how the global flame transfer function is changed with different injection strategies, forced flame images are studied. It is shown that the changes in flame transfer function is caused by the competition behavior between the local heat release responses for hydrogen piloted cases. Simply put, there is a phase difference between the local responses near the injection tube and the flame edges, causing a "pull-back" effect, which in turn causes a drop in the flame transfer function gain. Next the effect of different injection strategies on the pollutant emissions are investigated. It is demonstrated that adding hydrogen, in pilot injection or hydrogen enrichment configuration, causes a drop in \mathrm{CO_2} emissions for the same thermal power. Piloting strategies cause a slight increase in NOx emissions, however results show that an optimization is possible to obtain flames that are stable, low mathrm{CO_2} and low NOx. Finally, LES calculations and their comparisons with experimental results are presented. The capability of LES calculations in predicting flame responses is demonstrated and it is shown that the flame responses originate from the interactions of the vortices that are formed as a result of acoustic pulsations and the flames. Flames are wrapped around these vortices which increase the flame surface area. Further down the forcing cycle, the rolled up portions of the flames start touching the combustion chamber walls and gets quenched which causes a loss of flame surface area. These changes in flame surface area result in a fluctuating heat release rate, consisting the flame response
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Kojok, Ali Tarraf. "Hot jet ignition delay characterization of methane and hydrogen at elevated temperatures". Thesis, Pro Quest, 2017. https://doi.org/10.7912/C2CH35.
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Indiana University-Purdue University Indianapolis (IUPUI)This study contributes to a better understanding of ignition by hot combustion gases which finds application in internal combustion chambers with pre-chamber ignition as well as in wave rotor engine applications. The experimental apparatus consists of two combustion chambers: a pre chamber that generates the transient hot jet of gas and a main chamber which contains the main fuel air blend under study. Variables considered are three fuel mixtures (Hydrogen, Methane, 50\% Hydrogen-Methane), initial pressure in the pre-chamber ranging from 1 to 2 atm, equivalence ratio of the fuel air mixture in the main combustion chamber ranging from 0.4 to 1.5, and initial temperature of the main combustion chamber mixture ranging from 297 K to 500 K. Experimental data makes use of 4 pressure sensors with a recorded sampling rate up to 300 kHz, as well as high speed Schlieren imaging with a recorded frame rate up to 20,833 frame per seconds. Results shows an overall increase in ignition delay with increasing equivalence ratio. High temperature of the main chamber blend was found not to affect hot jet ignition delay considerably. Physical mixing effects, and density of the main chamber mixture have a greater effect on hot jet ignition delay.
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Ayoub, Mechline. "Etude de l’extension du régime de combustion sans flamme aux mélanges Méthane/Hydrogène et aux environnements à basse température". Thesis, Rouen, INSA, 2013. http://www.theses.fr/2013ISAM0010/document.
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La combustion sans flamme est un régime de combustion massivement dilué associant forte efficacité énergétique et très faibles émissions polluantes dans les fours industriels. La composition du combustible et la température des parois de la chambre de combustion sont deux paramètres très influents de ce régime. Dans de précédents travaux menés au CORIA, l’étude du régime de combustion sans flamme des mélanges méthane-hydrogène à 18% d’excès d’air a mené à des résultats originaux et prometteurs. D’autre part, la haute température des parois s’est avérée un élément primordial pour la stabilisation de la combustion sans flamme. Dans le cadre du projet CANOE en collaboration avec GDF SUEZ et l’ADEME, cette thèse a pour objectif, d’une part de compléter l’étude de l’extension de ce régime à des mélanges méthane-hydrogène pour des conditions opératoires plus proches des conditions classiques de fonctionnement de brûleurs (10% d’excès d’air), et d’autre part, d'étudier les problèmes de stabilité de la combustion sans flamme en environnement à basse température pour envisager son application à des configurations de type chaudière industrielle.Sur le four pilote à hautes températures de parois du CORIA, l’ajout de l’hydrogène dans le combustible a permis de garder le régime de combustion sans flamme pour toutes les proportions méthane - hydrogène avec très peu d’émissions polluantes. Une augmentation de l’excès d’air est toutefois nécessaire pour certaines conditions opératoires. Les expériences réalisées avec abaissement progressif de la température des parois ont permis d’étudier l’influence de celle-ci sur le développement de la combustion sans flamme, et d’atteindre les limites de stabilité de ce régime. Des résultats similaires sont obtenus sur une installation semi-industrielle de GDF SUEZ. L’ajout d’hydrogène rend la combustion sans flamme moins sensible à l’abaissement de la température de parois. Une étude analytique de jets turbulents confinés a été développée pour représenter l'interaction entre les jets de réactifs et leur environnement dans la chambre de combustion permettant d'atteindre le régime de combustion sans flamme par entraînement, dilution et préchauffage. Ce modèle nous a permis d’établir une étude systématique permettant de mettre en valeur l’effet de chaque paramètre sur le développement des jets dans l’enceinte, et ainsi servir de moyen de pré-dimensionnement de brûleur à combustion sans flamme. L'apport de chaleur nécessaire à la stabilisation à basse température a ainsi été estimé. Sur cette base, un brûleur adapté aux configurations à parois froides a été dimensionné et fabriqué. L’applicabilité de la combustion sans flamme avec ce brûleur dans une chambre de combustion à parois froides, spécialement conçue et fabriquée dans cet objectif au cours de cette thèse, a été étudiée. Un régime de combustion diluée à basses températures a pu être stabilisé, mais le fort taux d'imbrûlés produits en sortie reste à réduireMild flameless combustion is a massively diluted combustion regime associating high energy efficiency and very low pollutant emissions from industrial furnaces. The fuel composition and walls temperature are two very influential parameters of this combustion regime. In previous works realized at CORIA, flameless combustion of methane - hydrogen mixtures at 18% of excess air has shown very promising results. In another hand, high walls temperature is an essential element for flameless combustion stabilization. Within the framework of the project CANOE in collaboration with GDF SUEZ and ADEME, the objective of this PhD thesis is to complete the study of flameless combustion for methane-hydrogen mixtures in operating conditions similar to classical operating conditions of burners (10% of excess air), and in another hand, to study the stability limits of this combustion regime in low temperature environment like in industrial boiler.Experiments realized on the CORIA high temperature pilot facility, have proved that hydrogen addition in the fuel keep flameless combustion regime stable for all methane - hydrogen proportions, with very ultra-low pollutant emissions. An increase of excess air is however necessary for some operating conditions.Experiments realized with wall temperature progressive decrease allowed to study the influence of this parameter on flameless combustion, and to reach its stability limits. Similar results are obtained on the semi-industrial facility of GDF SUEZ. With hydrogen addition, flameless combustion is less sensitive to wall temperature decrease. An analytical representation of confined turbulent jets has been then developed to represent interaction between the reactant jets and their environment in the combustion chamber allowing reaching fameless combustion regime by entrainment, dilution and preheating. The effect of each parameter on the development of the jets can be then studied, which can be used as convenient tool of flameless combustion burners design. The heat quantity necessary for the low wall temperature stabilization has been quantified. On this base, a burner adapted to the configurations with cold walls has been designed. The applicability of the flameless combustion with this burner has been studied in a combustion chamber with low wall temperature specially designed for this purpose during this thesis. A mild diluted combustion regime has been achieved, but the high levels of unburnt gases have to be reduced
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Michelon, Nicola. "Modelling and experimental investigation of microkinetic in heterogeneous catalysis: hydrogen combustion and production". Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424703.
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This thesis investigates both hydrogen combustion and production, focusing on fundamentals of Pt-catalysed oxidation and steam methane reforming on nickelbased catalysts.
On the first aspect, we started reporting and investigating discrepancies on the structure and predictions of detail surface kinetic models from Literature, for H2-O2 reaction on Pt. Quantitative comparisons have been carried out through a closed-vessel, well-stirred reactor model with catalytic internal surface. Discrepancies in the predictions of the microkinetic models apparently comes from disagreement in the experimental date they are based on. Differences in experimental set-ups and Pt surface structure prompted us to develop own data, using plane Pt surface in suitable reactors. A novel laboratory reactor to investigate hydrogen oxidation on Pt surfaces has been designed, based on modelling, and built.
Experimental catalytic activity test proved that Pt activity can vary dramatically. Catalyst pretreatments with H2 and O2 revealed the mechanism of competition for surface sites as well as restructuring of the surface. Significantly long transformation was measured, particularly after catalyst O2 pretreatment, that are not included in the elementary chemistry models from Literature. Reaction lightoff at H2 lean compositions have been measured and compared with Literature experimental data, providing explanations for the differences among published data.
Subsequently, transient simulation of hydrogen combustion in platinumcoated channel has been adopted to evaluate the behavior under heterogeneous and hetero-/homogeneous chemistries. Effects of catalyst support material properties, FeCr-alloy and cordierite, have been compared. Implication for the operation of various practical catalytic reactors are finally drawn.
Concerning H2 production, we investigated the catalytic reforming of natural gas, by steam, both theoretically and experimentally. We identified relevant ranges of operative variables to study the catalyst at industrially relevant conditions. We designed by scaling down from industrial plants an original set-up to investigate the reaction kinetics at high-pressure (10 bars). We compared three nickel-based catalysts at low steam-to-carbon conditions, approaching S/C = 1, to collect activity and coking data for validation and development of detailed surface chemistry model.Questa tesi investiga sia la combustion che la produzione di idrogeno, con particolare attenzione verso aspetti fondamentali della ossidazione catalizzata da platino e la reazione di steam reforming del metano su catalizzatori a base di nickel. Per quanto riguarda il primo aspetto, siamo partiti dall’osservare ed approfondire discrepanze sulla struttura e sui risultati di modelli cinetici di reazioni superficiali presenti in Letteratura, per la reazione di H2 e O2 su Pt. I confronti quantitativi sono stati fatti utilizzando un Modello di reattore chiuso ben mescolato con le superfici interne catalitiche. Le differenze nelle perizie dei diversi modelli sembrano discendere da differenze nei dati sperimentali su cui sono stati calibrati. Il fatto che se non state utilizzate diverse configurazioni sperimentali, e probabilmente strutture delle superfici di Pt , ci ha stimolato a intraprendere una campagna sperimentale per ottenere dati propri, utilizzando superfici di platino planari in opportuni reattori. Un nuovo reattore di laboratorio, a flusso stagnante, per indagare reazioni su Pt in forma di dischi e stato progettato sulla base di una` modellazione dettagliata e realizzato in laboratorio. I risultati sperimentali hanno dimostrato che l’attivita del Pt può variare enormemente. Pretrattamenti con H2 o O2 Hanno chiarito il meccanismo della competizione per siti superficiali e la possibilita di ristrutturazione la superficie. Sono state misurate trasformazioni di lunga durata, soprattutto dopo pretrattamenti con O2, che non trova una spiegazione in nessuno dei modelli cineticidettagliati di letteratura. Mediante misure in rampa di temperatura si e studiato` l’innesco di miscele povere di H2 in aria. Il confronto con dati di letteratura suggerisce una plausibile interpretazione della discrepanza dei dati riportati. Successivamente simulazioni transitorie della combustione di idrogeno in canali rivestiti di platino e stato utilizzato per valutare il comportamento della`reazione eterogenea con e senza reazione omogenea. L’effetto delle proprieta`del supporto del catalizzatore sono stati confrontati, considerando leghe Fe-Cre cordierite. Le implicazioni pratiche per l’operativita di questi reattori sono state`delineate. Per quanto riguarda la produzione di idrogeno abbiamo studiato sia dal punto di vista teorico che sperimentale la reazione di reforming di gas naturale mediante7 vapore. Abbiamo identificato intervalli significativi da un punto di vista industriale per le variabili operative, per studiare la cinetica dei catalizzatori. Abbiamo progettato un reattore di laboratorio mediante regole di scala rispetto a un impianto modello industriale di riferimento, con l’obiettivo di studiare la reazione a pressioni elevate (10bars). Abbiamo confrontato tre catalizzatori basati su Nickel con formulazioni diverse, modificando rapporto vapore/carbonio in alimentazione, per avvicinarsi alle condizioni stechiometriche. Si sono raccolti numerosi ,dati sia di attivita cataliticha che di formazione di carbone, utili per uno sviluppo di modelli` cinetici dettagliati della reazione superficiale.
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Luo, Siwei. "Conversion of Carbonaceous Fuel to Electricity, Hydrogen, and Chemicals via Chemical Looping Technology - Reaction Kinetics and Bench-Scale Demonstration". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397573499.
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Burguburu, Joseph. "Etude expérimentale de la stabilité d’une flamme dans une chambre de combustion aéronautique par recirculation de gaz brûlés et par ajout d’hydrogène". Thesis, Rouen, INSA, 2012. http://www.theses.fr/2012ISAM0010/document.
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Les réglementations sur les NOx émis par les avions sont sévères. Les techniques les réduisant ont des inconvénients. Pour les supprimer, deux pistes sont explorées. La première modifie l'architecture des chambres de combustion et les stabilise par une cavité. La seconde dope le kérosène au ralenti.Peu d'information est disponible sur les mécanismes de stabilisation et sur la structure de flamme des Trapped Vortex Combustor. Pour y remédier, un TVC est construit. L'étude de l'écoulement à froid ainsi que l'étude temporellement résolue de la flamme, mettent en avant les éléments stabilisateurs et déstabilisateurs. L'impact de la structure de flamme sur les émissions est évalué.La seconde partie porte sur l'effet de l'ajout d'hydrogène et de gaz de reformeur dans une chambre conventionnelle. Malgré une légère augmentation des émissions de NOx, l'ajout de composés hydrogénés réduit fortement les émissions de CO, augmente la stabilité et réduit la limite d'extinction pauvreEnvironmental standards on aircraff NOx emissions are strict. Technics for reducing them have drawbacks. Two options are explored in this study to supress them. The first one is to fundamentally change the current combustion chamber architecture, to stabilize them by a cavity, the second, to dope fuel at idle.Little information on the mechanisms of stabilization and on the flame structure on Trapped Vortex Combustor is available. To remedy this, a TVC is built. The stabilizing ans destabilizing parameters are pointed out by the cold flow investigation and the temporally resolved study of the combustion. The impact of the flame structure on pollutant emissions is also considered.The second part of this stud, deals with the addition of pure hydrogen an of reformer gas in a conventional combustuion chamber. Despite a slight increase in NOx emissions, the addition of hydrogenated compounds reduces drastically CO emissions, increases the flame stability and reduces the LBO limit
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Gordon, Robert Lindsay. "A numerical and experimental investigation of autoignition". Thesis, The University of Sydney, 2008. http://hdl.handle.net/2123/4944.
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This body of research uses numerical and experimental investigative techniques to further the understanding of autoignition. Hydrogen/nitrogen and methane/air fuel configurations of turbulent lifted flames in a vitiated coflow burner are used as model flames for this investigation. Characterisation was undertaken to understand the impact of controlling parameters and the overall behaviour of the flames, and to provide a body of data for modelling comparisons. Modelling of the flames was conducted using the PDF-RANS technique with detailed chemistry incorporated using In-situ Adaptive Tabulation (ISAT) within the commercial CFD package, FLUENT 6.2. From these investigations, two numerical indicators for autoignition were developed: convection-reaction balance in the species transport budget at the mean flame base; and the build-up of ignition precursors prior to key ignition species. These indicators were tested in well defined autoignition and premixed flame cases, and subsequently used with the calculated turbulent lifted flames to identify if these are stabilised through autoignition. Based on learnings from the modelling, a quantitative, high-resolution simultaneous imaging experiment was designed to investigate the correlations of an ignition precursor (formaldehyde: CH2O) with a key flame radical (OH) and temperature. Rayleigh scattering was used to measure temperature, while Laser Induced Fluorescence (LIF) was used to measure OH and CH2O concentrations. The high resolution in the Rayleigh imaging permitted the extraction of temperature gradient data, and the product of the OH and CH2O images was shown to be a valid and useful proxy for peak heat release rate in autoigniting and transient flames. The experimental data confirmed the presence of formaldehyde as a precursor for autoignition in methane flames and led to the identification of other indicators. Sequenced images of CH2O, OH and temperature show clearly that formaldehyde exists before OH and peaks when autoignition occurs, as confirmed by images of heat release. The CH2O peaks decrease later while those of OH remain almost unchanged in the reaction zone.
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Gordon, Robert Lindsay. "A numerical and experimental investigation of autoignition". University of Sydney, 2008. http://hdl.handle.net/2123/4944.
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Doctor of Philosophy(PhD)This body of research uses numerical and experimental investigative techniques to further the understanding of autoignition. Hydrogen/nitrogen and methane/air fuel configurations of turbulent lifted flames in a vitiated coflow burner are used as model flames for this investigation. Characterisation was undertaken to understand the impact of controlling parameters and the overall behaviour of the flames, and to provide a body of data for modelling comparisons. Modelling of the flames was conducted using the PDF-RANS technique with detailed chemistry incorporated using In-situ Adaptive Tabulation (ISAT) within the commercial CFD package, FLUENT 6.2. From these investigations, two numerical indicators for autoignition were developed: convection-reaction balance in the species transport budget at the mean flame base; and the build-up of ignition precursors prior to key ignition species. These indicators were tested in well defined autoignition and premixed flame cases, and subsequently used with the calculated turbulent lifted flames to identify if these are stabilised through autoignition. Based on learnings from the modelling, a quantitative, high-resolution simultaneous imaging experiment was designed to investigate the correlations of an ignition precursor (formaldehyde: CH2O) with a key flame radical (OH) and temperature. Rayleigh scattering was used to measure temperature, while Laser Induced Fluorescence (LIF) was used to measure OH and CH2O concentrations. The high resolution in the Rayleigh imaging permitted the extraction of temperature gradient data, and the product of the OH and CH2O images was shown to be a valid and useful proxy for peak heat release rate in autoigniting and transient flames. The experimental data confirmed the presence of formaldehyde as a precursor for autoignition in methane flames and led to the identification of other indicators. Sequenced images of CH2O, OH and temperature show clearly that formaldehyde exists before OH and peaks when autoignition occurs, as confirmed by images of heat release. The CH2O peaks decrease later while those of OH remain almost unchanged in the reaction zone.
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Thellmann, Andreas [Verfasser], Christian [Akademischer Betreuer] Mundt i Klaus [Akademischer Betreuer] Hornung. "Impact of Gas Radiation on Viscous Flows, in particular on Wall Heat Loads, in Hydrogen-Oxygen vs. Methane-Oxygen Systems, based on the SSME Main Combustion Chamber / Andreas Thellmann. Betreuer: Christian Mundt. Gutachter: Klaus Hornung. Universität der Bundeswehr München, Fakultät für Luft- und Raumfahrttechnik". Neubiberg : Universitätsbibliothek der Universität der Bundeswehr, 2010. http://d-nb.info/1007710314/34.
Pełny tekst źródłaKsiążki na temat "Hydrogen methane combustion"
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R, Thomas S., i United States. National Aeronautics and Space Administration., red. Numerical study of contaminant effects on combustion of hydrogen, ethane and methane in air. [Washington, DC]: National Aeronautics and Space Administration, 1995.
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R, Thomas S., i United States. National Aeronautics and Space Administration., red. Numerical study of contaminant effects on combusstion if hydrogen,ethaneand methane in air. [Washington, DC]: National Aeronautics and Space Administration, 1995.
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Eichert, Helmut. Zur Dynamik des Verbrennungsablaufs von Wasserstoff-Luft- und Wasserstoff-Methan-Luft-Gemischen. Koln: DLR, 1989.
Znajdź pełny tekst źródłaCzęści książek na temat "Hydrogen methane combustion"
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Rubtsov, Nikolai M. "Influence of Metallic Pt on Hydrogen and Methane Combustion". W Key Factors of Combustion, 207–32. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-45997-4_8.
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Rubtsov, Nickolai M., Kirill Ya Troshin i Michail I. Alymov. "Features of Combustion of Hydrogen–Methane–Air Fuels Over Surfaces of Noble Metals". W Catalytic Ignition of Hydrogen and Hydrogen-Hydrocarbon Blends Over Noble Metals, 153–84. Cham: Springer Nature Switzerland, 2023. http://dx.doi.org/10.1007/978-3-031-28416-8_4.
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Ammendola, P., R. Chirone i G. Ruoppolo. "Zero Emissions Hydrogen Production by Fluidized Bed Catalytic Decomposition of Methane". W Proceedings of the 20th International Conference on Fluidized Bed Combustion, 1035–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-02682-9_161.
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Khanlari, Amin, Ali Salavati-Zadeh, Mobin Mohammadi, Seyyed Bahram Nourani Najafi i Vahid Esfahanian. "Effect of Hydrogen Enrichment on Pollutant and Greenhouse Gases Formation and Exergy Efficiency of Methane MILD Combustion". W Environmentally-Benign Energy Solutions, 403–29. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20637-6_22.
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İlbaş, Mustafa, Zehra Gökalp Öztürk i Serhat Karyeyen. "Three-Dimensional Numerical Modelling of Hydrogen, Methane, Propane and Butane Combustions in a Spherical Model Combustor". W Progress in Exergy, Energy, and the Environment, 991–1000. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-04681-5_94.
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Di Iorio, S., P. Sementa i B. M. Vaglieco. "Optical diagnostics for the analysis of hydrogen–methane blend combustion in internal combustion engines". W Compendium of Hydrogen Energy, 233–61. Elsevier, 2016. http://dx.doi.org/10.1016/b978-1-78242-363-8.00009-8.
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Albayrak, Bilge. "Use of Hydrogen-Methane Blends in Internal Combustion Engines". W Hydrogen Energy - Challenges and Perspectives. InTech, 2012. http://dx.doi.org/10.5772/50597.
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de Klerk, Arno, i Vinay Prasad. "Methane for Transportation Fuel and Chemical Production". W Materials for a Sustainable Future, 327–84. The Royal Society of Chemistry, 2012. http://dx.doi.org/10.1039/bk9781849734073-00327.
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Methane is the main component of natural gas. Natural gas is an important energy carrier for distributed heating and transportation applications and it is the most efficient carbon source for the production of synthesis gas (H2+CO). The value of natural gas lies in its high H:C ratio, low heteroatom content and fluid nature. Sustainability is best served by restricting the use of methane for distributed and mobile energy applications, where the clean-up of combustion gases is impractical or infeasible, and also for the synthesis of hydrogen-rich products. For the production of fuels and chemicals, both direct methods, such as liquefied natural gas, and indirect methods, such as methanol and Fischer–Tropsch synthesis, are considered. Guidelines for sustainability as applied to gas-to-liquids conversion are provided. The processes and the refining requirements to produce on-specification transportation fuels are discussed. The processes for petrochemical and lubricant production from methane are likewise discussed.
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Cassim, Shaakirah, i Shehzaad Kauchali. "Minimising CO2 Emissions from Coal Gasification". W Recent Advances in Gasification Technologies [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.105587.
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Traditional coal-to-liquid processes use gasification with excess steam to obtain hydrogen-rich syngas for downstream manufacturing of methanol or Fischer-Tropsch liquids. Such processes are shown to produce very large amounts of CO2 directly by the Water-Gas-Shift (WGS) reaction or, indirectly, by combustion in raising steam. It is shown how any coal gasifier can operate under auto-thermal conditions with methane as source of hydrogen instead of steam. This co-gasification system produces syngas for a poly-generation facility while minimising the formation of process CO2. It is shown that minimal steam is required for the process and a limit on the maximum amount of H2:CO can be obtained. Co-gasification of coal is shown to have a major advantage in that a separate WGS reactor is not required, less CO2 is formed and methane is reformed non-catalytically within the gasification unit. Furthermore, regions of thermally balanced operations were identified that enabled a targeting approach for the design of co-gasification systems. The method will guide gasification practitioners to incorporate fossil fuels and renewable-H2 into coal-to-liquids processes that require syngas with H2:CO ratio of 2. An important result shows that low-grade coals can be co-gasified with methane to obtain CO2-free syngas ideal for power generation.
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Davidenko, D. M., I. Gökalp, E. Dufour i D. Gaffié. "Numerical simulations of supersonic combustion of methane-hydrogen fuel in an experimental combustion chamber". W Parallel Computational Fluid Dynamics 2003, 529–36. Elsevier, 2004. http://dx.doi.org/10.1016/b978-044451612-1/50068-8.
Pełny tekst źródłaStreszczenia konferencji na temat "Hydrogen methane combustion"
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Ghenai, Chaouki, i Khaled Zbeeb. "Combustion of Hydrogen Enriched Hydrocarbon Fuels in Vortex Trapped Combustor". W ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39641.
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Trapped vortex combustor represents an efficient and compact combustor for flame stability. Combustion stability is achieved through the use of cavities in which recirculation zones of hot products generated by the direct injection of fuel and air are created and acting as a continuous source of ignition for the incoming main fuel-air stream. Computational Fluid Dynamics analysis was performed in this study to test the combustion performance and emissions from the vortex trapped combustor when natural gas fuel (methane) is replaced with renewable and alternative fuels such as hydrogen and synthesis gas. The flame temperature, the flow field, and species concentrations inside the Vortex Trapped Combustor were obtained. The results show that hydrogen enriched hydrocarbon fuels combustion will result in more energy, higher temperature (14% increase when methane is replaced with hydrogen fuels) and NOX emissions, and lower CO2 emissions (50% decrease when methane is replaced with methane/hydrogen mixture with 75% hydrogen fraction). The NOX emission increases when the fraction of hydrogen increases for methane/hydrogen fuel mixture. The results also show that the flame for methane combustion fuel is located in the primary vortex region but it is shifted to the secondary vortex region for hydrogen combustion.
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Alavandi, S. K., i A. K. Agrawal. "Lean Premixed Combustion of Methane and Hydrogen-Enriched Methane Using Porous Inert Media". W ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53231.
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This paper presents an experimental investigation on lean premixed combustion of methane and hydrogen-enriched methane. The combustion was stabilized on the surface of a porous inert media made of silicon-carbide coated carbon core with 4 pores per centimeter. Experiments were conducted using commercial grade methane (99% purity) and a mixture of 70% methane and 30% hydrogen, by volume. Measurements of NOx and CO emissions were taken for a range of airflow rates and adiabatic flame temperatures. The combustor turndown ratio was varied by a factor of 6. Emission characteristics were compared for a given adiabatic flame temperature, representing energy input to the combustor. Results show lower CO emissions and extended lean blow off limit when hydrogen was added to the methane fuel.
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Singh, Kapil, Bala Varatharajan, Ertan Yilmaz, Fei Han i Kwanwoo Kim. "Effect of Hydrogen Combustion on the Combustion Dynamics of a Natural Gas Combustor". W ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-51343.
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In a carbon-constrained world, Integrated Gasification Combined Cycle (IGCC) systems achieve excellent environmental performance and offer a more economical pre-combustion CO2 removal compared to other coal-based systems. The residual gas after carbon removal is comprised primarily of hydrogen and nitrogen mixtures. Achieving stable combustion of hydrogen-rich fuel mixtures while producing ultra-low NOx emissions (much lower than current diffusion combustion technology) is challenging. The goal of this study was to characterize the stability of lean premixed combustion systems operating with hydrogen and establish boundaries for stable operation. Modeling and experimental efforts were directed towards demonstration of the feasibility of such systems while meeting the emissions requirements. The higher flame speed and heat-release rate achievable with hydrogen-containing fuels can change the dynamics and stability characteristics of the combustors compared to natural gas. A combustion rig was modeled using an in-house combustion dynamics analysis code. In the model, flame heat-release fluctuations were captured by considering the effect of upstream fuel-air ratio fluctuations and flow speed fluctuations. CFD simulations were used to obtain combustion parameters. The results showed the effect of using hydrogen instead of methane and the simulations correctly predicted the combustor modes and their instability for hydrogen as well as methane combustion.
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Pappa, Alessio, Laurent Bricteux, Pierre Bénard i Ward De Paepe. "Can Water Dilution Avoid Flashback on a Hydrogen Enriched Micro Gas Turbine Combustion? A Large Eddy Simulations Study". W ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14777.
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Abstract Considering the growing interest in Power-to-Fuel, i.e. production of H2 using electrolysis to store excess renewable electricity, combustion-based technologies still have a role to play in the future of power generation. Especially in a decentralized production with small-scale cogeneration, micro Gas Turbines (mGTs) offer great advantages related to their high adaptability and flexibility, in terms of operation and fuel. Hydrogen (or hydrogen enriched methane) combustion is well-known to lead to flame and combustion instabilities. The high temperatures and reaction rates reached in the combustor can potentially lead to flashback. In the past, combustion air humidification (i.e. water addition) has proven effective to reduce temperatures and reaction rates, leading to significant NOx emission reductions. Therefore, combustion air humidification can open a path to stabilize hydrogen combustion in a classical mGT combustor. However accurate data assessing the impact of humidification on the combustion is still missing for real mGT combustor geometries and operating conditions. In this framework, this paper presents a comparison between pure methane and hydrogen enriched methane/air combustions, with and without combustion air humidification, in a typical mGT combustion chamber (Turbec T100) using Large Eddy Simulations (LES) analysis. In a first step, the necessary minimal water dilution, to reach stable and low emissions combustion with hydrogen, was assessed using a 1D approach. The one-dimensional unstretched laminar flame is computed for both pure methane (reference case) and hydrogen enriched methane/air combustion cases. The results of this comparison show that, for the hydrogen enriched combustion, the same level of flame speed as in the reference case can be reached by adding 10% (in mass fraction) of water. In a second step, the feasibility and flexibility of humidified hydrogen enriched methane/air combustion in an industrial mGT combustor have been demonstrated by performing high fidelity LES on a 3D geometry. Results show that steam dilution helped to lower the reactivity of hydrogen, and thus prevents flashback, enabling the use of hydrogen blends in the mGT at similar CO levels, compared to the reference case. These results will help to design future combustor towards more stability.
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Kim, H. S., V. K. Arghode i A. K. Gupta. "Hydrogen Addition Effects on Swirl Stabilized Methane Flame". W ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-34133.
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Effect of hydrogen addition in methane-air premixed flames has been examined from a swirl stabilized combustor under confined flame conditions. Different swirlers have been examined to investigate the effect of swirl intensity on enriching methane-air flame with hydrogen in a laboratory-scale pre-mixed combustor operated at 5.81 kW. The flame stability was examined at same head load (5.81 kW) for various parameters such as amount of hydrogen addition, combustion air flow rates and swirl strengths. This was done by comparing adiabatic flame temperatures at the lean flame limit. The combustion characteristics of hydrogen enriched methane flames at constant heat load but different swirl strength were examined using particle image velocimetry (PIV), OH chemiluminescence, micro-thermocouples diagnostics to provide information on velocity and temperature field, and combustion generated OH concentration in the flame. Gas analyzer was used to obtain NOx and CO concentration at the exit. The results show that the the lean stability limit is mostly extended by hydrogen addition, but it can reduce in case of higher swirl intensity operating at lower adiabatic flame temperatures. The addition of hydrogen increases the NOx emission; however, this effect can be reduced by increasing either the excess air or swirl intensity. The results of NOx and CO emissions were also compared with a diffusion flame type combustor. The NOx emissions of hydrogen enriched methane premixed flame was found to be lower than the corresponding diffusion flame under the fuel lean condition.
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Shih, Hsin-Yi, i Chi-Rong Liu. "A Computational Study of Hydrogen Substitution Effects on the Combustion Performance for a Micro Gas Turbine". W ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-45275.
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The effects of hydrogen substitution on methane/air combustion in a micro gas turbine were studied in this work. The combustion performance and emission characteristics of a can type combustor were investigated with model simulations using the commercial code STAR-CD, in which the three-dimension compressible k-ε turbulent flow mode and presumed probability density function for chemical reaction between methane/hydrogen/air mixtures were used. With hydrogen being the substituent, not a supplement to methane, the detailed flame structures, distributions of flame temperature and flow velocity, and gas emissions were presented and compared by using a fraction of hydrogen to substitute methane in the combustor. For the scenarios from pure methane to pure hydrogen, results show the flame temperature and exit gas temperature increase when only 10% methane is substituted. But as hydrogen substitution percentage increases, the flame temperature and exit gas temperature decrease because of a power shortage caused by lower mass flow rate and heating value of the resulting blended fuels, although the pattern factor drops drastically compared to that of pure methane. As the fuel inlet velocity decreases from 100 m/s to 20 m/s, the high temperature region shifts to the side of the combustor due to the high diffusivity of hydrogen. Increasing hydrogen substitution percentage at a fixed fuel injection velocity reduces NOx emission due to lower flame temperature, but CO emissions increase continually with increasing hydrogen substitution percentage because oxygen depletion for methane/air combustion. Before hydrogen blended fuels or pure hydrogen are used as an alternative fuel for the micro gas turbine, further experimental testing are needed as the CFD modeling results provide a guidance for the improved designs of the combustor.
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BYKOVSKII, F. A., S. A. ZHDAN i E. F. VEDERNIKOV. "SPECIFIC IMPULSES FOR CONTINUOUS DETONATION OF METHANE/HYDROGEN-AIR MIXTURES". W 8TH INTERNATIONAL SYMPOSIUM ON NONEQUILIBRIUM PROCESSES, PLASMA, COMBUSTION, AND ATMOSPHERIC PHENOMENA. TORUS PRESS, 2020. http://dx.doi.org/10.30826/nepcap2018-2-24.
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Regimes of continuous spin detonation (CSD) with transverse detonation waves (TDWs) are obtained in a flow-type annular cylindrical combustor DK-500 for fuel-air mixtures (FAMs) with two compositions of the binary fuel CH4 + 8H2 and CH4 +4H2. Regimes of continuous multifront detonation (CMD) with colliding TDWs are obtained for the FAM with the CH4 + 2H2 binary fuel. These regimes are characterized by significant irregularity of the TDW structure and by a comparatively low TDW velocity. Specific impulses in continuous detonation are determined and analyzed for different compositions of the methane/hydrogen binary fuel. The maximum measured values of the specific impulse at the combustor exit are approximately 3800 s in CSD of CH4 + 8H2 and CH4 + 4H2, 3200 s in CMD of CH4 + 2H2, and 1600 s in combustion of CH4 + H2.
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Roy, Rishi, i Ashwani K. Gupta. "Characteristics of Swirl-Stabilized Distributed Combustion With Hydrogen-Enriched Methane". W ASME 2022 Power Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/power2022-85402.
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Abstract Distributed combustion was investigated with hydrogen-enriched methane fuel in a swirl-stabilized burner. Distributed reaction zones were established from conventional swirl flames at two heat release intensities of 5.72 and 7.63 MW/m3-atm by diluting the main airstream with carbon dioxide. The appearance of distributed reaction zones with hydrogen addition to methane fuel was investigated here. High-speed chemiluminescence imaging was performed for different cases without any spectral filtering to visualize the shape of reaction zones. A gradual increase of % H2 in the fuel mixture increased the chemiluminescence intensity and reduced the flame standoff distance gradually in both the swirl and distributed combustion cases. The reaction zone at higher thermal intensities was found to be wider than the lower thermal intensity case. Distributed reaction zones possessed lower visible chemiluminescence signatures than that of the conventional swirl flames considered. The increased flame chemiluminescence signatures with hydrogen enrichment were related to higher flame reactivity because of hydrogen addition. This hypothesis was verified by computing the laminar flame speed at various hydrogen-enriched cases at different O2 concentrations. The results revealed that the flame speed gradually decreased when the flame transitioned from swirl combustion to distributed combustion regime. Additionally, higher flame speed was observed at different O2 levels corresponding to higher hydrogen content in the fuel mixture.
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Rosen, Stanford, Mark Pfeil, Yen Yu i William Anderson. "Effects of Hydrogen Addition on Combustion Stability of an Unstable Methane Rocket Combustor". W 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2011. http://dx.doi.org/10.2514/6.2011-328.
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Vijaykant, S., i Ajay Agrawal. "Numerical Investigation of Swirl Stabilized Combustion of Lean Premixed Methane and Hydrogen Enriched Methane". W 43rd AIAA Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2005. http://dx.doi.org/10.2514/6.2005-167.
Pełny tekst źródłaRaporty organizacyjne na temat "Hydrogen methane combustion"
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Lieuwen, Tim, i Jared Kee. PR-592-16208-R01 Effect of Variability in Fuel on Operation and Reliability of Gas Turbine. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), marzec 2017. http://dx.doi.org/10.55274/r0011023.
Pełny tekst źródłaStreszczenie:
Pipeline natural gas, while dominantly composed of methane, also contains various amounts of diluents, hydrogen, and hydrocarbons. The objective of this report is to describe how variations in fuel composition influence gas turbine emissions, operability, and operational range (turndown). A key point of this report is that these fuel composition sensitivities are not described by a single parameter, such as Wobbe index, but by different parameters depending upon the specific issue. For example, the autoignition time is an important parameter influencing autoignition risk, while flame speed has important influences on combustion instability and blowoff risk. This report explains these sensitivities, as well as approaches for identifying and mitigating operational risk. This report has a related webinar.