Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach ...for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.
•Ammonia combustion technologies in piston engines and gas turbine are reviewed.•Hydrogen mass fraction ~10% is needed for modest piston engine performances.•Multiple fuel injections optimisation ...enhances piston engine performances.•Partially premixed combustion leads to satisfactorily low nitric oxide emission.•Thorough studies on nitrogen-based emissions are still needed.
The worldwide decarbonisation movement has turned ammonia into one of the attractive alternative fuel for power generation. This paper reviews the progress of ammonia combustion technologies in spark ignition engine, compression ignition engine, and gas turbine. Relevant publications from prominent academic journals were acquired from credible scholarly databases and analysed. Ammonia dissociation and separate hydrogen supply were typically employed to deliver hydrogen to enhance ammonia reaction in the spark ignition engine. To achieve satisfactory engine performances with thermal efficiency of around 30%, a hydrogen mass fraction of roughly 10% is required for the ammonia/hydrogen engine. Engine parameters optimisation may be needed to increase hydrogen mass fraction further. Aqueous ammonia elevates heat release rate of full load compression ignition engine by almost 10%. However, prolonged ignition delay could potentially lead to higher engine noise levels. Multiple fuel injection optimisation is seemingly a more promising solution for improving ammonia compression ignition engine performances. In recent years, partial premixed combustion has gained considerable interest in hydrogen/ammonia gas turbine combustion research. This is mainly due to its ability to operate at equivalence ratio as low as 0.4, and in the slight fuel-rich regime. For operation at equivalence ratio 1.05, the nitric oxide concentration was decreased by a factor of approximately 5.9 when compared with that of stoichiometric condition. In all, ammonia offers a practical opportunity for sustainable power generation via internal combustion engines and gas turbine. Ground-breaking combustion technologies are crucial to boost the adoption of ammonia in these engines.
The major challenge in the current context of the rising world energy demand is to limit the global temperature increase for mitigating climate change. This goal requires a large reduction of COsub.2 ...emissions, mainly produced by power generation and industrial processes using fossil fuels. In this study, a novel methodology for Ksub.2COsub.3-doped Lisub.4SiOsub.4 sorbents production for COsub.2 capture at high temperatures was adopted based on the Design of Experiments (DoE). This innovative approach systematically tested different synthesis (temperature and Ksub.2COsub.3 content) and adsorption conditions (sorption temperature and COsub.2 concentration), allowing for the assessment of individual and interactive effects of process parameters. The Response Surface Methodology (RSM) was employed to obtain non-linear predictive models of COsub.2 uptake and Lisub.4SiOsub.4 conversion. The results of RSM analysis evidenced a maximum adsorption capacity of 196.4 mg/g for a sorbent produced at 600 °C and with 36.9 wt% of Ksub.2COsub.3, tested at 500 °C and 4 vol% of COsub.2. Whereas at 50 vol% of COsub.2, the best uptake of 295.6 mg/g was obtained with a sorbent synthesized at 600 °C, containing less Ksub.2COsub.3 (17.1 wt%) and tested at a higher temperature (662 °C). These findings demonstrate that Ksub.2COsub.3-doped Lisub.4SiOsub.4 sorbents can be tailored to maximize COsub.2 capture under various operating conditions, making them suitable for use in industrial processes.
A comprehensive reference for engineers and researchers, this second edition focuses on gas turbine heat transfer issues and their associated cooling technologies for aircraft and land-based gas ...turbines. It provides information on state-of-the-art cooling technologies such as advanced turbine blade film cooling and internal cooling schemes.
Combustion features of CH4/NH3/H2 ternary blends Mashruk, S.; Vigueras-Zuniga, M.O.; Tejeda-del-Cueto, M.E. ...
International journal of hydrogen energy,
08/2022, Letnik:
47, Številka:
70
Journal Article
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The use of so-called “green” hydrogen for decarbonisation of the energy and propulsion sectors has attracted considerable attention over the last couple of decades. Although advancements are ...achieved, hydrogen still presents some constraints when used directly in power systems such as gas turbines. Therefore, another vector such as ammonia can serve as a chemical to transport and distribute green hydrogen whilst its use in gas turbines can limit combustion reactivity compared to hydrogen for better operability. However, pure ammonia on its own shows slow, complex reaction kinetics which requires its doping by more reactive molecules, thus ensuring greater flame stability. It is expected that in forthcoming years, ammonia will replace natural gas (with ∼90% methane in volume) in power and heat production units, thus making the co-firing of ammonia/methane a clear path towards replacement of CH4 as fossil fuel. Hydrogen can be obtained from the pre-cracking of ammonia, thus denoting a clear path towards decarbonisation by the use of ammonia/hydrogen blends. Therefore, ammonia/methane/hydrogen might be co-fired at some stage in current combustion units, hence requiring a more intrinsic analysis of the stability, emissions and flame features that these ternary blends produce. In return, this will ensure that transition from natural gas to renewable energy generated e-fuels such as so-called “green” hydrogen and ammonia is accomplished with minor detrimentals towards equipment and processes. For this reason, this work presents the analysis of combustion properties of ammonia/methane/hydrogen blends at different concentrations. A generic tangential swirl burner was employed at constant power and various equivalence ratios. Emissions, OH∗/NH∗/NH2∗/CH∗ chemiluminescence, operability maps and spectral signatures were obtained and are discussed. The extinction behaviour has also been investigated for strained laminar premixed flames. Overall, the change from fossils to e-fuels is led by the shift in reactivity of radicals such as OH, CH, CN and NH2, with an increase of emissions under low and high ammonia content. Simultaneously, hydrogen addition improves operability when injected up to 30% (vol), an amount at which the hydrogen starts governing the reactivity of the blends. Extinction strain rates confirm phenomena found in the experiments, with high ammonia blends showing large discrepancies between values at different hydrogen contents. Finally, a 20/55/25% (vol) methane/ammonia/hydrogen blend seems to be the most promising at high equivalence ratios (1.2), with no apparent flashback, low emissions and moderate formation of NH2/OH radicals for good operability.
•Ternary blends of ammonia/methane/hydrogen are poorly understood.•Operability maps improve with the content of methane and hydrogen.•Extinction strain rates suffer considerable relative variation at high ammonia contents.•High ammonia content blends shift from OH/CH/NH formation to NH2 at high equivalence ratios.•There are blends that present low emissions and high operability with low carbon content.
Alternative fuels are still needed to compensate for the energy shortages caused by fossil fuel depletion. The paper aims to brief the types of alternative fuels used for the past 30 years. Moreover, ...it includes the recent types of biofuels (especially biodiesel) and their blends with studies on the performances and the exhaust emissions for different engines. In this study, previous studies were analysed, the challenges faced by the researchers were examined, and incentives for using biodiesel fuel in engines were discussed. The engine performance and emissions when using biodiesels and their blends in different engine models were also surveyed. All biodiesels and their blends have demonstrated the ability to reduce emissions such as carbon oxide (CO), carbon dioxide (CO2), nitrogen oxide (NOx), particulate matter (PM) and hydrocarbon (HC) under various operating conditions, as well as the ability to improve the performance of the gas turbine. It is necessary to understand the combustion properties of fuels for their use in an engine. The contribution of this review is to help the engine manufacturers and researchers develop further research relating to readjusting and optimising the biodiesel engine and its relevant system.
•Less effort has been made on using dual biodiesel to improve engine performance.•Seed oil methyl ester has the highest brake power compared to other biofuels.•Karanja biodiesel has the highest brake thermal efficiency than other biofuels.•The lowest emissions level have achieved by Mahua and Vegetable Oil Ethyl Ester.
Overview of the Possibility of Using Low-Power Gas Turbines Chichirova, Natalia D; Filimonova, Antonina A; Cherkasov, Aleksandr S ...
Journal of Siberian Federal University. Engineering & Technologies,
07/2023, Letnik:
16, Številka:
5
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Аннотация. В данной статье произведен обзор представленных на рынке газовых турбин малой мощности отечественных и зарубежных производителей. Также рассмотрены сферы и опыт их применения в различных ...отраслях, особенности эксплуатации и дальнейшие перспективы внедрения. Проанализированы тенденции развития данной тематики в научных публикациях российских и зарубежных источников. При этом большее внимание уделено именно агрегатам отечественного производства, их особенностям и возможности применения. Выявлены проблемы и противоречия, препятствующие активному развитию газотурбинных технологий малой мощности в Российской Федерации.
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This study focuses on combustion, emission, and performance analysis of JET-A fuel blends with various additives using a micro gas turbine engine. The amount of oxygen in fuel blends ...and atomization are the crucial parameters in the production of a higher combustion rate with less emission. Therefore, various ratios of additives (ethanol and pentanol) are blended with biofuel (rapeseed and canola-sunflower oil) to form the JET-A fuel blends by using Kay’s and Grunberg-Nissan mixing rules. The combustion, performance and emission parameters under different engine loads were examined. Results showed that all the blends logged higher static thrust with an appreciable reduction rate in the consumption of the fuel. Among different fuel blends, R20E (Jet-A 70% fuel, 20% Rapeseed, and 10% ethanol) showed 35% increase in static thrust associated with 41% reduction in thrust specific fuel consumption. Moreover, the blends R20E and CS20E (Jet-A fuel 70%, Canola- Sunflower 20% and 10% ethanol) indicated 24% and 10% increase in thermal efficiency respectively due to the influence of ethanol concentration and higher oxygen content. In addition, these fuel blends generate less emission of environmental unfriendly harmful gases, including NOx, CO, and HC, compared to neat Jet-A fuel. Results revealed that the exergy destruction values are higher for the combustion chamber than the other conventional fuel components.
The microstructural and optical reflectivity response of photonic SiO.sub.2/TiO.sub.2 nanomultilayers have been investigated as a function of temperature and up to the material system's melting ...point. The nanomultilayers exhibit high, broadband reflectivities up to 1350 °C with values that exceed 75% for a 1 mum broad wavelength range (600-1600 nm). The optimized nanometer sized, dielectric multilayers undergo phase transformations from anatase TiO.sub.2 and amorphous SiO.sub.2 to the thermodynamically stable phases, rutile and cristobalite, respectively, that alter their structural morphology from the initial multilayers to that of a scatterer. Nonetheless, they retain their photonic characteristics, when characterized on top of selected substrate foils. The thermal behavior of the nanometer sized multilayers has been investigated by differential thermal analysis (DTA) and compared to that of commercially available, mm-sized, annealed powders. The same melting reactions were observed, but the temperatures were lower for the nm-sized samples. The samples were characterized using X-ray powder diffraction before DTA and after annealing at temperatures of 1350 and 1700 °C. The microstructural evolution and phase compositions were investigated by scanning electron microscopy and energy-dispersive X-ray spectroscopy measurements. The limited mutual solubility of one material to another, in combination with the preservation of their optical reflectivity response even after annealing, makes them an interesting material system for high-temperature, photonic coatings, such as photovoltaics, aerospace re-entry and gas turbines, where ultra-high temperatures and intense thermal radiation are present.
•New combinations of CCHP system with gas engine, diesel engine and gas turbine as prime movers have been presented.•The performance of prime movers have been analyzed separately and simultaneously ...at six different scenarios.•Energy, exergy and economic analyses of the CCHP system have been performed and the best scenario has been selected.•The combination of the gas and diesel engines has been proposed as the best scenario.
In this paper, a combined cooling, heating and power (CCHP) system has been designed under an electric charge supply strategy for a residential complex in Iran.
The aim of this research is energy, exergy and economic analyses of the CCHP system with using different prime mover arrangements and presenting appropriate condition of its operation according to these viewpoints.
For this purpose, three types of gas engine, diesel engine, and gas turbine as prime movers have been presented and analyzed separately and simultaneously at six different scenarios and the appropriate scenario has been proposed for the CCHP system. In addition, the performance of system has been estimated at various part load conditions. The system is modeled and simulated using thermodynamic and economic relationships by using a computer code in the MATLAB software. The results show that the CCHP system under the electricity supply strategy with the simultaneous combination of two prime movers has significant advantages over one of them.
The CCHP efficiency with two prime movers increases up to 10% compared to that of a single prime mover as well as the exergy efficiency. Additionally, scenario 4 by combining the gas engine and diesel engine is selected as the best scenario. It has 87% energy efficiency, 62.8% exergy efficiency, and operating cost reduction of about 80%. Also, the payback period is 6.3 years by taking interest rate into account and 1.36 years regardless of it.
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