Academic literature on the topic 'Ammonia fuel blends'
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Journal articles on the topic "Ammonia fuel blends"
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Lanotte, Alfredo, Vincenzo De Bellis, and Enrica Malfi. "Potential of hydrogen addition to natural gas or ammonia as a solution towards low- or zero-carbon fuel for the supply of a small turbocharged SI engine." E3S Web of Conferences 312 (2021): 07022. http://dx.doi.org/10.1051/e3sconf/202131207022.
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Nowadays there is an increasing interest in carbon-free fuels such as ammonia and hydrogen. Those fuels, on one hand, allow to drastically reduce CO2 emissions, helping to comply with the increasingly stringent emission regulations, and, on the other hand, could lead to possible advantages in performances if blended with conventional fuels. In this regard, this work focuses on the 1D numerical study of an internal combustion engine supplied with different fuels: pure gasoline, and blends of methane-hydrogen and ammonia-hydrogen. The analyses are carried out with reference to a downsized turbocharged two-cylinder engine working in an operating point representative of engine operations along WLTC, namely 1800 rpm and 9.4 bar of BMEP. To evaluate the potential of methane-hydrogen and ammonia-hydrogen blends, a parametric study is performed. The varied parameters are air/fuel proportions (from 1 up to 2) and the hydrogen fraction over the total fuel. Hydrogen volume percentages up to 60% are considered both in the case of methane-hydrogen and ammonia-hydrogen blends. Model predictive capabilities are enhanced through a refined treatment of the laminar flame speed and chemistry of the end gas to improve the description of the combustion process and knock phenomenon, respectively. After the model validation under pure gasoline supply, numerical analyses allowed to estimate the benefits and drawbacks of considered alternative fuels in terms of efficiency, carbon monoxide, and pollutant emissions.
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Xiao, Hua, Aiguo Chen, Minghui Zhang, Yanze Guo, and Wenxuan Ying. "Using Ammonia as Future Energy: Modelling of Reaction Mechanism for Ammonia/Hydrogen Blends." Journal of Physics: Conference Series 2361, no. 1 (October 1, 2022): 012012. http://dx.doi.org/10.1088/1742-6596/2361/1/012012.
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To utilize ammonia-based fuels, it is fundamental to understand chemical mechanisms of combustion process, in which reaction characteristics of such a chemical are described in detail. Detailed chemical-kinetics mechanism of ammonia was modelled by an automatic reaction mechanism generation program to investigate characteristics of premixed combustion for ammonia/hydrogen fuel mixture. To develop an accurate model for practical combustion applications, validation of the reaction mechanism was carried out in terms of laminar flame speed under different conditions. Results suggested that the established mechanism model has satisfying performance under different ammonia/hydrogen ratio conditions. Moreover, comparison with other mechanism models demonstrated that the developed model can be used to describe flame propagation of ammonia/hydrogen fuels. Then characteristics of laminar flame speed were predicted under various ammonia concentration and equivalence ratio conditions. Sensitivity analyses showed that ammonia mole fraction has a prominent impact on kinetics of flame speed for ammonia/hydrogen blends. Flame structure analyses showed that hydrogen can enhance ammonia flames with higher light radical concentrations whilst deteriorate NOx emission in exhaust gases.
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Vigueras-Zúñiga, Marco Osvaldo, Maria Elena Tejeda-del-Cueto, Syed Mashruk, Marina Kovaleva, Cesar Leonardo Ordóñez-Romero, and Agustin Valera-Medina. "Methane/Ammonia Radical Formation during High Temperature Reactions in Swirl Burners." Energies 14, no. 20 (October 14, 2021): 6624. http://dx.doi.org/10.3390/en14206624.
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Recent studies have demonstrated that ammonia is an emerging energy vector for the distribution of hydrogen from stranded sources. However, there are still many unknown parameters that need to be understood before ammonia can be a substantial substitute in fuelling current power generation systems. Therefore, current attempts have mainly utilised ammonia as a substitute for natural gas (mainly composed of methane) to mitigate the carbon footprint of the latter. Co-firing of ammonia/methane is likely to occur in the transition of replacing carbonaceous fuels with zero-carbo options. Hence, a better understanding of the combustion performance, flame features, and radical formation of ammonia/methane blends is required to address the challenges that these fuel combinations will bring. This study involves an experimental approach in combination with numerical modelling to elucidate the changes in radical formation across ammonia/methane flames at various concentrations. Radicals such as OH*, CH*, NH*, and NH2* are characterised via chemiluminescence whilst OH, CH, NH, and NH2 are described via RANS κ-ω SST complex chemistry modelling. The results show a clear progression of radicals across flames, with higher ammonia fraction blends showing flames with more retreated shape distribution of CH* and NH* radicals in combination with more spread distribution of OH*. Simultaneously, equivalence ratio is a key parameter in defining the flame features, especially for production of NH2*. Since NH2* distribution is dependent on the equivalence ratio, CFD modelling was conducted at a constant equivalence ratio to enable the comparison between different blends. The results denote the good qualitative resemblance between models and chemiluminescence experiments, whilst it was recognised that for ammonia/methane blends the combined use of OH, CH, and NH2 radicals is essential for defining the heat release rate of these flames.
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Xiao, Hua, Agustin Valera-Medina, and Philip J. Bowen. "Modeling Combustion of Ammonia/Hydrogen Fuel Blends under Gas Turbine Conditions." Energy & Fuels 31, no. 8 (July 26, 2017): 8631–42. http://dx.doi.org/10.1021/acs.energyfuels.7b00709.
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Božo, Milana Guteša, and Agustin Valera-Medina. "Prediction of Novel Humified Gas Turbine Cycle Parameters for Ammonia/Hydrogen Fuels." Energies 13, no. 21 (November 2, 2020): 5749. http://dx.doi.org/10.3390/en13215749.
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Carbon emissions reduction via the increase of sustainable energy sources in need of storage defines chemicals such as ammonia as one of the promising solutions for reliable power decarbonisation. However, the implementation of ammonia for fuelling purposes in gas turbines for industry and energy production is challenging when compared to current gas turbines fuelled with methane. One major concern is the efficiency of such systems, as this has direct implications in the profitability of these power schemes. Previous works performed around parameters prediction of standard gas turbine cycles showed that the implementation of ammonia/hydrogen as a fuel for gas turbines presents very limited overall efficiencies. Therefore, this paper covers a new approach of parameters prediction consisting of series of analytical and numerical studies used to determine emissions and efficiencies of a redesigned Brayton cycle fuelled with humidified ammonia/hydrogen blends. The combustion analysis was done using CHEMKIN-PRO (ANSYS, Canonsburg, PA, USA), and the results were used for determination of the combustion efficiency. Chemical kinetic results denote the production of very low NOx as a consequence of the recombination of species in a post combustion zone, thus delivering atmospheres with 99.2% vol. clean products. Further corrections to the cycle (i.e., compressor and turbine size) followed, indicating that the use of humidified ammonia-hydrogen blends with a total the amount of fuel added of 10.45 MW can produce total plant efficiencies ~34%. Values of the gas turbine cycle inlet parameters were varied and tested in order to determine sensibilities to these modifications, allowing changes of the analysed outlet parameters below 5%. The best results were used as inputs to determine the final efficiency of an improved Brayton cycle fuelled with humidified ammonia/hydrogen, reaching values up to 43.3% efficiency. It was notorious that humidification at the injector was irrelevant due to the high water production (up to 39.9%) at the combustion chamber, whilst further research is recommended to employ the unburned ammonia (0.6% vol. concentration) for the reduction of NOx left in the system (~10 ppm).
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Li, Conghao, Jingfu Wang, Ying Chen, and Xiaolei Zhang. "Numerical study of the Effect of CO2 on the NH3/CH4 Counterflow Diffusion Flame in O2/CO2/N2 Atmosphere." IOP Conference Series: Earth and Environmental Science 898, no. 1 (October 1, 2021): 012006. http://dx.doi.org/10.1088/1755-1315/898/1/012006.
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Abstract Ammonia, as a carbon-neutral fuel, draws people attentions recently. NH3/CH4 blends is considered as a kind of fuel. A numerical simulation of the effects of CO2 dilution on the combustion characteristics and NO emission of NH3/CH4 counterflow diffusion flame was conducted in this study. Diffusion flame structure, the influence of CO2 radiation characteristics on temperature and NO emission characteristics were studies at normal temperature and pressure. The dilution and radiation of CO2 reduce the flame temperature significantly. NO concentration decreased with the CO2 mole fraction increase effectively. The study extends the basic combustion characteristics of NH3 containing fuel.
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Kang, Lianwei, Weiguo Pan, Jiakai Zhang, Wenhuan Wang, and Congwei Tang. "A review on ammonia blends combustion for industrial applications." Fuel 332 (January 2023): 126150. http://dx.doi.org/10.1016/j.fuel.2022.126150.
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Fernández-Tarrazo, E., R. Gómez-Miguel, and M. Sánchez-Sanz. "Minimum ignition energy of hydrogen–ammonia blends in air." Fuel 337 (April 2023): 127128. http://dx.doi.org/10.1016/j.fuel.2022.127128.
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Medhat, Moataz, Adel Khalil, and Mohamed A. Yehia. "A Numerical Study of Decarbonizing Marine Gas Turbine Emissions Through Ammonia/Hydrogen Fuel Blends." Journal of Physics: Conference Series 2304, no. 1 (August 1, 2022): 012008. http://dx.doi.org/10.1088/1742-6596/2304/1/012008.
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Abstract The employment of gas turbine in combination with diesel engines and steam generators is a well-known power generation technique in modern marines and ship propulsion. Previously, it rendered its foundations in marine industry through higher power weight ratios and lower NOx emissions if compared to pure diesel engine driven marines. As climate change concerns are becoming more serious, the decarbonization of marine combustion products is becoming of environmental concern. In the present study a modified design of the burner and combustor was suggested to allow for the longer residence time required for releasing the combustion products from the ‘slow’ burning ammonia molecule. Afterwards, the more formidable challenge of relatively higher NOx emissions was treated through analysis of the effect of altering the equivalence ratio, hydrogen blending, increasing the combustor working pressure and staging the combustion. The latest tactic resulted in lowering values of exit NOx to around 30 ppmv, which is a quite promising result.
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Yapicioglu, Arda, and Ibrahim Dincer. "Experimental investigation and evaluation of using ammonia and gasoline fuel blends for power generators." Applied Thermal Engineering 154 (May 2019): 1–8. http://dx.doi.org/10.1016/j.applthermaleng.2019.02.072.
Full textDissertations / Theses on the topic "Ammonia fuel blends"
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Colson, Sophie. "Fundamental flame characteristics and combustion chemistry for ammonia/methane blended fuels." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI103.
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L’étude de combustibles décarbonés, tel que l’ammoniac, est essentielle dans le contexte du réchauffement climatique. Sa combustion nécessite cependant de relever plusieurs défis, notamment concernant la stabilisation des flammes et la production de NOx. Afin de pallier les problèmes de stabilisation, une solution consiste à utiliser un mélange d’ammoniac avec un autre combustible. Cette thèse a pour objectif l’analyse des caractéristiques fondamentales de la combustion d’un mélange ammoniac-méthane, encore peu étudié. Il s’agira de comprendre les mécanismes cinétiques conduisant à la formation de polluants et ceux contrôlant la stabilisation. Dans ce but, le travail portera d’abord sur la chimie de combustion de ces mélanges, afin de clarifier leurs propriétés, notamment la structure de la flamme et les émissions engendrées. L’étude des mécanismes réactionnels, déjà validés dans un domaine limité de conditions, a montré de réelles disparités lorsque les conditions d’étude étaient élargies. Il est donc essentiel d’évaluer ces mécanismes dans des configurations diversifiées et sur une plus large base de résultats expérimentaux. Quatre mécanismes ont été sélectionnés et évalués dans une configuration à contre-courant, via l’étude du taux d’étirement à l’extinction et l’analyse des profils d’espèces OH et NO. La stabilisation de ces flammes a ensuite été étudiée, en examinant l’influence de l’ajout d’ammoniac sur une flamme de méthane de type jet non-pré-mélangée. L’évolution des limites de suspension, de rattachement et l’étendue de la zone d’hystérésis ont notamment été examinés. La dynamique de (dé)stabilisation de la flamme attachée au brûleur, sa suspension et son rattachement ont été étudiés pour comprendre l’évolution particulière de ces régimes. Les résultats montrent une forte diminution du domaine de stabilisation avec l’ajout d’ammoniac ainsi qu’un comportement singulier de la limite de ré-attachement. Enfin, l’étude de la flamme attachée a souligné l’importance des couplages aérodynamique et chimique dans la dynamique de stabilisation du bout de flammeThe study of low-carbon fuels, such as ammonia, is essential in the context of global warming. However, its combustion is challenging, particularly regarding flame stabilization and NOx emission. One solution to overcome the stabilization issues is to use a mixture of ammonia with another fuel. The aim of this thesis is the analysis of the fundamental combustion characteristics of an ammonia-methane mixture, which remains merely investigated in the literature. The objective is to understand the kinetic mechanisms leading to the formation of pollutants and the mechanisms controlling stabilization. For that purpose, this work will first focus on the combustion chemistry of these mixtures, to clarify their properties, and more specifically the structure of the flame and the emissions generated. The study of the reaction mechanisms, already validated in a limited range of conditions, showed real disparities when the range of experimental conditions is broadened. It is therefore essential to evaluate these mechanisms in diverse configurations and on a broader range of experimental results. Four detailed chemistry mechanisms were selected and evaluated in a counterflow configuration, studying the extinction stretch rate and analyzing OH and NO species profiles. The stabilization of these flames was then studied, by examining the influence of the addition of ammonia to a methane non-premixed jet flame in an air coflow. The evolution of liftoff and re-attachment limits and the hysteresis region were investigated. The dynamics of stabilization of the flame attached to the burner, its liftoff and its re-attachment have been studied to understand the particular evolution of these regimes. The results show a strong decrease in the stabilization domain with the addition of ammonia as well as a singular behavior of the re-attachment limit. Finally, the study of the attached flame highlighted the importance of aerodynamic and chemical couplings in the stabilization dynamics of the flame tip
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Issayev, Gani. "Autoignition and reactivity studies of renewable fuels and their blends with conventional fuels." Diss., 2021. http://hdl.handle.net/10754/667809.
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Population growth and increasing standards of living have resulted in a rapid demand for energy. Our primary energy production is still dominated by fossil fuels. This extensive usage of fossil fuels has led to global warming, environmental pollution, as well as the depletion of hydrocarbon resources. The prevailing difficult situation offers not only a challenge but also an opportunity to search for alternatives to fossil fuels. Hence, there is an urgent need to explore environmentally friendly and cost-effective renewable energy sources. Oxygenates (alcohols, ethers) and ammonia are among the potential renewable alternative fuels of the future.
This thesis investigates the combustion characteristics of promising alternative fuels and their blends using a combination of experimental and modelling methodologies. The studied fuels include ethanol, diethyl ether, dimethyl ether, dimethoxy methane, γ-valerolactone, cyclopentanone, and ammonia. For the results presented in this thesis, the studies may be classified into three main categories:
1. Ignition delay time measurements of ethanol and its blends by using a rapid compression machine and a shock tube. The blends studied include binary mixtures of ethanol/diethyl ether and ternary mixtures of ethanol/diethyl ether/ethyl levulinate. A chemical kinetic model has been constructed and validated over a wide range of experimental conditions. The results showed that a high-reactivity fuel, diethyl ether, may be blended with a low-reactivity fuel, ethanol, in varying concentrations to achieve the desired combustion characteristics. A ternary blend of ethanol/diethyl ether/ethyl levulinate may be formulated from a single production stream, and this blend is shown to behave similarly to a conventional gasoline.
2. Ignition delay time and flame speed measurements of ammonia blended with combustion promoters by utilizing a rapid compression machine and a constant volume spherical reactor. The extremely low reactivity of ammonia makes it unsuitable for direct use in many combustion systems. One of the potential strategies to utilize ammonia is to blend it with a combustion promoter. In this work, dimethyl ether, diethyl ether, and dimethoxy methane are explored as potential promoters of ammonia combustion. Chemical kinetic models were developed and validated in the high temperature regime by using flame speed data and in the low-to-intermediate temperature regime by using ignition delay time data. The results showed that even a small addition (~ 5 – 10%) of combustion promoters can significantly alter ammonia combustion, and diethyl ether was found to have the highest propensity to enhance ammonia ignition and flame propagation. Blends of combustion promoters with ammonia can thus be utilized in modern downsized turbo-charged engines.
3. Octane boosting and emissions minimization effects of next generation oxygenated biofuels. These studies were carried out using a cooperative fuel research engine operating in a homogenous charge compression ignition (HCCI) mode. The oxygenated fuels considered here include γ-valerolactone and cyclopentanone. The results showed that γ-valerolactone and cyclopentanone can be effective additives for octane boosting and emission reduction of conventional fuels.
Overall, the results and outcomes of this thesis will be highly useful in choosing and optimizing alternative fuels for future transportation systems.
Conference papers on the topic "Ammonia fuel blends"
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Haputhanthri, Shehan Omantha, Timothy Taylor Maxwell, John Fleming, and Chad Austin. "Ammonia and Gasoline Fuel Blends for Internal Combustion Engines." In ASME 2014 8th International Conference on Energy Sustainability collocated with the ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/es2014-6538.
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Ammonia, when blended with hydro carbon fuels, can be used as a composite fuel to power existing IC engines. Such blends, similar to ethanol and gasoline fuel blends, can be used to commercialize ammonia as an alternative fuel. Feasibility of developing ammonia gasoline liquid fuel blends and the use of ethanol as an emulsifier to enhance the solubility of ammonia in gasoline were studied using a small thermostated vapor liquid equilibrium (VLE) high pressure cell in this research. A larger VLE cell was used to develop identified fuel blends in sufficient quantities for engine dynamo-meter tests. A engine dynamometer equipped with a 2.4L gasoline engine was used to benchmark performance of ammonia fuel blends against standard fuels. Solubility test results proved that ethanol free gasoline is capable of dissolving 4.5% of ammonia on volume basis (23 g/l on mass basis) at 50 psi [344.7 kPa] pressure and 286.65 K temperature in liquid phase. Solubility levels are increased with the use of ethanol. Gasoline with 30% ethanol can retain 18% of ammonia in the liquid phase by volume basis (105 g/l by mass basis) at the same pressure and temperature. Dynamometer results show the ability of new composite fuel blends to produce the same amount of torque and power in the lower rpm limits. At higher rpm levels ammonia rich fuels result in an increased torque and power. Thus it can be concluded that hydrogen energy can be stored as ammonia-gasoline fuel blends and recovered back successfully without any strenuous modification to the existing infrastructure and end user equipment or behavior.
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Haputhanthri, Shehan Omantha, Timothy Taylor Maxwell, John Fleming, and Chad Austin. "Ammonia Gasoline-Ethanol/Methanol Tertiary Fuel Blends as an Alternate Automotive Fuel." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38026.
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Ammonia and hydrocarbon fuel blends, similar to ethanol and gasoline fuel blends can be used to commercialize ammonia as an alternative fuel. Feasibility of developing ammonia gasoline liquid fuel blends and the use of ethanol and methanol as emulsifiers to enhance the solubility of ammonia in gasoline were studied using thermostated vapor liquid equilibrium (VLE) high pressure cells, in this research. Solubility test results prove that emulsifier free pure gasoline is capable of dissolving 23 g/l of ammonia on mass basis (4.5% of ammonia on volume basis) at 345 kPa pressure and 286.65 K temperature in liquid phase. Solubility level is increased with the use of ethanol and methanol. Gasoline with 10% ethanol can retain 31.7 g/l (5.7% on volume basis) of ammonia in the liquid phase at the same pressure and temperature. Methanol has better emulsifying capabilities. Solubility level of gasoline with 30% methanol is 189.5 g/l (30.0% on volume basis). This paper presents solubility and dynamometer test results of five fuel blends E/M0, E10, M10, M20 and M30. Better performances are observed when the ammonia rich fuels are benchmarked against baseline fuel especially at higher engine speeds.
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Hewlett, S. G., D. G. Pugh, A. Valera-Medina, A. Giles, J. Runyon, B. Goktepe, and P. J. Bowen. "Industrial Wastewater As an Enabler of Green Ammonia to Power via Gas Turbine Technology." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14581.
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Abstract This experimental study follows on from detailed Chemkin-Pro numerical analyses assessing the viability of by-product ammonia (NH3) utilization for power generation in gas turbines (GTs). This study looks specifically at NH3 in the industrial wastewaters of steelworks, resulting from the cleansing of coke oven gas (COG). The by-product NH3 is present in an aqueous blend of 60–70%vol water and is normally destroyed. An experimental campaign was conducted using a premixed swirl burner in a model GT combustor, previously employed in the successful combustion of NH3/hydrogen blends, with favorable NOx and unburned fuel emissions. This study experimentally investigates the combustion performance of combining anhydrous and aqueous by-product NH3 in an approximate 50:50%vol blend, comparing the performance with that of each ammonia source unblended. Green anhydrous NH3, a rapidly growing research topic, is a carbon-free energy vector for renewable hydrogen. Some potential benefits of combining the two sources are suggested. Ammonia combustion presents two major challenges, poor reactivity and a potential for excessive NOx emissions. Prior numerical analyses predicted that 15%vol addition of steelworks COG, at an inlet temperature of 550 K, may provide sufficient support for raising the reactivity of the NH3-based fuels, whilst limiting undesirable emissions. Therefore, addition of 10, 15 and 20%vol COG to each NH3-based fuel was investigated experimentally at 25 kW power with inlet temperatures > 500 K, at atmospheric pressure. As nitric oxide (NO) emissions decrease significantly with increasing fuel-to-air ratio, experiments were conducted at equivalence ratios (Φ) between 1.0 and 1.3, the precise range of Φ for each blend being optimized according to the modeling predictions for emissions. Leading blends, anhydrous NH3 with 15%vol COG and the 50:50%vol blend with 15%vol COG, achieved < 100 ppm and < 200 ppm NO respectively. Modest-sized steel plants produce ∼10 metric tons of by-product NH3/day. Aspen Plus was used to model a Brayton-Rankine cycle with integrated recuperation. Adopting typical losses (48% cycle efficiency) and ∼1.2 MPa combustor inlet pressure, the net electrical power generation of 15%vol COG blended with 10 tonnes/day of aqueous industrial NH3 and 25 tonnes/day of anhydrous NH3 (i.e. achieving a 50:50%vol blend) was ∼4.7 MW, ∼47% more power than for the same amount of anhydrous NH3 with 15%vol COG. This significant increase, indicates how industrial NH3 could enable green NH3 to power.
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Ditaranto, Mario, Inge Saanum, and Jenny Larfeldt. "Experimental Study on Combustion of Methane / Ammonia Blends for Gas Turbine Application." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-83039.
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Abstract Hydrogen from renewables or reformed natural gas with CO2 Capture and Storage (CCS) can be used as fuel to achieve CO2 free power production. Because of the challenges related to transport and storage of H2, NH3 has been proposed as a hydrogen carrier as it can be stored in liquid form at moderate pressures and temperatures. NH3 can be used as a fuel directly, but the low reactivity and flame speed in air makes combustion stability challenging in conventional gas turbine combustors. As no solutions are commercially available today, a transitional approach is to only replace part of the fuel with NH3 to limit the change in the combustion properties, although this only partly decarbonizes the fuel. This study investigates combustion of CH4/NH3 blends with air in a downscaled Dry Low Emission (DLE) burner at pressures up to 6 bar and thermal power up to 100 kW. The effects of equivalence ratio and NH3/CH4 mixture ratio on the emissions of NOx, CO, CH4, HCN, N2O, and NH3 are studied at different pressures and power. Even small amounts of NH3 introduction in the fuel results in unacceptable high NOx emissions in a conventional combustor and the flame stability limits the maximum NH3 content in the fuel. However, by using a two-stage combustion strategy with a rich primary zone, NOx emissions down to ca. 100 ppm could be achieved with a NH3 content up to 100%, provided the thermal intensity of the combustor is severely reduced.
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Ditaranto, Mario, Inge Saanum, and Jenny Larfeldt. "Experimental Study on High Pressure Combustion of Decomposed Ammonia: How Can Ammonia Be Best Used in a Gas Turbine?" In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-60057.
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Abstract Hydrogen, a carbon-free fuel, is a challenging gas to transport and store, but that can be solved by producing ammonia, a worldwide commonly distributed chemical. Ideally, ammonia should be used directly on site as a fuel, but it has many combustion shortcomings, with a very low reactivity and a high propensity to generate NOx. Alternatively, ammonia could be decomposed back to a mixture of hydrogen and nitrogen which has better combustion properties, but at the expense of an endothermal reaction. Between these two options, a trade off could be a partial decomposition where the end use fuel is a mixture of ammonia, hydrogen, and nitrogen. We present an experimental study aiming at finding optimal NH3-H2-N2 fuel blends to be used in gas turbines and provide manufacturers with guidelines for their use in retrofit and new combustion applications. The industrial burner considered in this study is a small-scale Siemens burner used in the SGT-750 gas turbine, tested in the SINTEF high pressure combustion facility. The overall behaviour of the burner in terms of stability and emissions is characterized as a function of fuel mixtures corresponding to partial and full decomposition of ammonia. It is found that when ammonia is present in the fuel, the NOx emissions although high can be limited if the primary flame zone is operated fuel rich. Increasing pressure has shown to have a strong and favourable effect on NOx formation. When ammonia is fully decomposed to 75% H2 and 25% N2, the opposite behaviour is observed. In conclusion, either low rate or full decomposition are found to be the better options.
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Haputhanthri, Shehan O. "Ammonia Gasoline Fuel Blends: Feasibility Study of Commercially Available Emulsifiers and Effects on Stability and Engine Performance." In SAE 2014 International Powertrain, Fuels & Lubricants Meeting. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2014. http://dx.doi.org/10.4271/2014-01-2759.
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Wiseman, Samuel, Andrea Gruber, and James R. Dawson. "Flame Transfer Functions for Turbulent, Premixed, Ammonia-Hydrogen-Nitrogen-Air Flames." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-83298.
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Abstract Ammonia is a promising hydrogen and energy carrier but also a challenging fuel to use in gas turbines, due to its low flame speed, limited flammability range, and the production of NOx from fuel-bound nitrogen. Previous experimental and theoretical work has demonstrated that partially-dissociated ammonia (NH3/H2/N2 mixtures) can match many of the laminar flame properties of methane flames. Among the remaining concerns pertaining to the use of NH3/H2/N2 blends in gas turbines is their thermoacoustic behavior. This paper presents the first measurements of flame transfer functions (FTFs) for turbulent, premixed, NH3/H2/N2-air flames and compares them to CH4-air flames that have a similar unstretched laminar flame speed and adiabatic flame temperature. FTFs for NH3/H2/N2 blends were found to have a lower gain than CH4 FTFs at low frequencies. However, the cut-off frequency was found to be greater, due to a shorter flame length. The results suggest that NH3/H2/N2 blends may excite different thermoacoustic modes in gas turbines. In addition, the dependence of the flame response on forcing amplitude was measured for a forcing frequency of 650 Hz and the linearity of the NH3/H2/N2 flame response up to high forcing amplitudes suggests that particularly high-amplitude limit cycles may occur. For both CH4 flames and NH3/H2/N2 flames the confinement diameter was found to have a strong influence on peak gain values. The effect on the FTF phase was modest, except in the case of extreme confinement, where almost all of the flame is close to the wall, and in the case of a significant change in the flame stabilisation. Chemiluminescence resolved along the longitudinal direction shows a suppression of fluctuations when the flame first interacts with the wall followed by a subsequent recovery, but with a significant phase shift. Nevertheless, simple Strouhal number scalings based on the flame length and reactant bulk velocity at the dump plane result in a reasonable collapse of the FTF cut-off frequency and phase curves.
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Chen, Guanxing, Qizhuang Yu, Claes Brage, Christer Rosén, and Krister Sjöström. "Co-Gasification of Coal/Biomass Blends in a Pressurized Fluidized-Bed Gasifier: The Advantageous Synergies in the Process." In ASME 1999 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/99-gt-191.
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An experimental study on co-gasification of coal and biomass blends in an oxygen-containing atmosphere has been carried out in a pressurized fluidized-bed gasifier. Several different biomass materials including wood and energy crops were used in the study, whereas two coals ranked of bituminite from Poland and UK were used in the investigation. The gasifier used was a Laboratory Development Unit (LDU) with an inner diameter of 144 mm. The operation temperature was 900 °C, and the pressure was 0.4 MPa. The research was part of the European Commission’s APAS and JOULE III clean coal technology programs. The study was focused on possible synergistic effects in the thermochemical treatment of the fuel blends. The char formed was examined. The tar produced in the process was analyzed. The environmentally concerned nitrogen compounds emitted from the process were detected. An unexpected result was that the blends of the fuels and their char formed in situ exhibited higher gasification reaction rate under the studied conditions. The yield of char diminished and consequently the gas production increased. Furthermore, both the formation of tar and nitrogen compounds seemed also affected synergistically in co-gasification process of the fuel blends. The yields of tar and ammonia were lower than expected.
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Stiehl, Bernhard, Marcel Otto, Malcolm Newmyer, Max Fortin, Tommy Genova, Kareem Ahmed, Jayanta Kapat, Stefano Orsino, and Carlo Arguinzoni. "Numerical Study of Three Gaseous Fuels on the Reactor Length and Pollutant Formation Under Lean Gas Turbine Conditions." In ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/gt2022-83343.
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Abstract The present paper numerically studies the impact of three gaseous fuels on the reaction characteristics and pollutant formation in a lean combustion system. The models include an equilibrium calculation with Ansys-Chemkin-Pro, as well as a 3D half-width CFD model using Large Eddy Simulation (LES) and Adaptive Mesh Refinement (AMR) models. The outcomes are targeted to benefit the transition to carbon-free operation of aviation turbines. Three fuels, methane (CH4), hydrogen (H2), and ammonia (NH3) as well as blends thereof were compared at constant equivalence ratios to obtain a firing temperature level of T = 1800°C. The kinetic mechanism in use was suggested and validated by Okafor et al., including 42 species to describe CH4/H2/NH3-air combustion and NOx chemistry. The formation of nitrogen oxide pollutants (NO, NO2 and N2O) were analyzed to determine the sensitivity to the three fuels and their blends. Secondly, a fuel injector scaling study was performed, and a significantly larger jet diameter was selected to compensate for the increased stoichiometric mixture fraction and reduced blend density relative to CH4-fueled architecture. Lastly, the three-dimensional AMR-LES model provided validation of the injector re-sizing, as well as further insight into the expected fuel-air distribution by convective mixing. While the substitution of methane-fueled gas turbines with carbon-free alternatives is generally feasible, blending of H2 and NH3 fuels could be a promising strategy to utilize existing turbine combustors, while retaining reaction timescales close to those of CH4-powered systems.
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Hewlett, S. G., A. Valera-Medina, D. G. Pugh, and P. J. Bowen. "Gas Turbine Co-Firing of Steelworks Ammonia With Coke Oven Gas or Methane: A Fundamental and Cycle Analysis." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-91404.
Full textAbstract:
Abstract Following on from successful experimental trials employing ammonia/hydrogen blends in a model gas turbine combustor, with favorable NOx and unburned fuel emissions, a detailed numerical study has been undertaken to assess the viability of using steelworks by-product ammonia in gas turbines. Every metric ton (tonne) of steel manufactured using a blast furnace results in approximately 1.5 kg of by-product ammonia, usually present in a vapor form, from the cleansing of coke oven gas (COG). This study numerically investigates the potential to utilize this by-product for power generation. Ammonia combustion presents some major challenges, including poor reactivity and a propensity for excessive NOx emissions. Ammonia combustion has been shown to be greatly enhanced through the addition of support fuels, hydrogen and methane (both major components of COG). CHEMKIN-PRO is employed to demonstrate the optimal ratio of ammonia vapor, and alternatively anhydrous ammonia recovered from the vapor, to COG or methane at equivalence ratios between 1.0 and 1.4 under an elevated inlet temperature of 550K. Aspen Plus was used to design a Brayton-Rankine cycle with integrated recuperation, and overall cycle efficiencies were calculated for a range of favorable equivalence ratios, identified from the combustion models. The results have been used to specify a series of emissions experiments in a model gas turbine combustor.