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Cracking Ammonia: panel wrap-up from the Ammonia Energy Conference

When should we be cracking ammonia? How much should we be cracking? How could better cracking technologies open up new end uses? What are the critical challenges still to be overcome for cracking ammonia? On November 17, 2020, the Ammonia Energy Association (AEA) hosted a panel discussion moderated by Bill David from Science and Technology Facilities Council (STFC), as well as panel members Josh Makepeace from the University of Birmingham, Joe Beach from Starfire Energy, Gennadi Finkelshtain from GenCell Energy, Camel Makhloufi from ENGIE, and Michael Dolan from Fortescue as part of the recent Ammonia Energy Conference. All panelists agreed that cracking technology as it stands has a number of key areas to be optimised, particularly catalyst improvements and energy efficiency. But, successful demonstrations of modular, targeted cracking solutions are accelerating the conversation forward.

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Performance of Ammonia-Natural Gas Co-Fired Gas Turbine for Power Generation

Ammonia is paid special attention as renewable energy carrier [1-3], because it offers advantages in generation, transportation and utilization. Haber-Bosch method is already established as ammonia generation method; large amount of ammonia is already used as fertilizer and chemical raw material. Ammonia can be liquefied at room temperature. Its transport and storage system are already established. Ammonia is cheaper to transport than hydrogen. Ammonia can be used as carbon-free fuel in internal combustion engines as alternative to conventional hydrocarbon fuels. However, it has different combustion characteristics. For example, the nitrogen atom contained in the ammonia molecule, causes high NOx emission…

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Two Stage Ammonia Combustion in a Gas Turbine like Combustor for Simultaneous NO and Unburnt Ammonia Reductions

Ammonia is expected not only as a hydrogen energy carrier but also as a carbon free fuel. Recently, ammonia fueled gas turbine combustor was successfully demonstrated. However, large amount of NOx was produced when ammonia burns because ammonia includes nitrogen atom in the ammonia molecule. In addition, unburnt ammonia concentration in exhaust gas also needs to be reduced. In this study, we proposed a combustion concept in order to reduce NO and unburnt ammonia concentrations in the exhaust gas simultaneously in a gas turbine like model swirl combustor. In this concept, two stage (rich – lean) combustion was employed. Two…

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Development of Low-NOx Combustor of Micro Gas Turbine Firing Ammonia Gas

A massive influx of renewable energy is required in order to mitigate global warming. Although hydrogen is a renewable media, its storage and transportation in large quantity is difficult. Ammonia, however, is a hydrogen energy carrier, and its storage and transportation technology is already established. Although ammonia fuel combustion was studied in the 1960s in the USA, the development of an ammonia fuel gas turbine had been abandoned because combustion efficiency was unacceptably low [1]. Recent demand for hydrogen energy carrier revives the usage of ammonia fuel. The National Institute of Advanced Industrial Science and Technology (AIST) in Japan, in…

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Ammonia-Hydrogen Power for Combustion Engines

Ammonia blends can potentially become a breakthrough chemical for power generation, cooling storage and distribution of energy. Gas turbines and internal combustion engines are potential candidates for the use of the resource in an efficient way that will enable commissioning of combined cycles to power communities around Europe and around the world while serving as sources of heat and chemical storage. Therefore, development of these systems will bring to the market a safer, zero carbon fuel that can be used for multiple purposes, thus decentralizing power generation and increasing sustainability in the communities of the future whilst positioning the developing…

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Development of ammonia / natural gas dual fuel gas turbine combustor

NH3 is a carbon-free fuel, so it has the potential to reduce CO2 emission from the power plant when used as a fuel. However, NH3 has combustion characteristics different from conventional hydrocarbon fuels. The N atom in the ammonia molecule causes high NOx emission through combustion reactions. To develop a gas-turbine combustor, which burns a combination of NH3 and natural gas with controlled emissions, combustion characteristics have been studied experimentally and numerically by using a swirl-burner, which is typically used in gas-turbines. Detailed exhaust gas compositions of the burner have been measured under atmospheric pressure and fuel lean conditions. As…

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Combustion characteristics of ammonia/air flames for a model swirl burner and an actual gas turbine combustor

Ammonia is expected not only as hydrogen energy carrier but also as carbon free fuel. For an industrial use of ammonia combustor, ammonia flame stabilized on a swirl combustor should be clarified. However, in order to realize an ammonia-fueled combustor, there are some issues to be solved, such as a difficulty of flame stabilization and reductions of NOx and ammonia emission. In this study, stabilization and emission characteristics of ammonia / air flames stabilized by a model swirl burner are investigated. The outer and inner diameters of the swirler are 24 mm and 14 mm, respectively, and the swirl number…

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NOx emission analysis and flame stabilization of ammonia-hydrogen-air premixed flames

Based on its well-known merits, ammonia has been gaining special attention as a potential renewable energy carrier which can be replaced in power generation units. One of the major challenges with ammonia as a fuel is NOx emission, which has a complex underlying chemical kinetics. In an earlier chemical kinetics study by the authors, NOx formation sensitivity was thoroughly studied in a wide range of combustion conditions [Nozari & Karabeyoğlu, J.Fuel 2015]. As the next step, premixed ammonia-hydrogen-air flames are studied experimentally in standard temperature and pressure condition. Effects of some major influential parameters on NOx emission levels are investigated:…

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Numerical investigation of combustion characteristics of ammonia-air mixtures under high pressure lean conditions

In this numerical study we investigate the combustion characteristics of ammonia-air mixtures at elevated pressure and lean conditions which are encountered in gas turbine combustors. The Konnov mechanism is implemented to predict the laminar burning velocity, autoignition, species concentrations and the sensitivity analysis of ammonia decomposition and laminar flame speed. A laminar premixed freely propagating flame model is implemented to calculate burning velocity, mole fractions of species, and contribution of reactions in molar conversion of specific species. Also a homogenous reactor model is used to analyze the temporal mole fraction of radicals and ignition delay time. Effects of adding hydrogen…