The UTSR Program conducts research to increase the efficiency and performance of gas turbines while lowering emissions. There is renewed interest in the use of hydrogen, a clean-burning fuel, for turbine-based electricity generation.
Hydrogen production from fossil fuels, coupled with carbon capture, utilization, and storage, can generate low-cost hydrogen with net-negative carbon emissions. Waste plastics could be added to the fuel mix to produce large quantities of hydrogen and to mitigate the impact of plastics in the environment.
This FOA focuses on fundamental and applied research to enable the use of hydrogen as a gas turbine fuel. Selected projects will support university-based R&D to resolve fundamental scientific challenges and applied engineering issues of combustion turbines fueled with pure hydrogen, hydrogen and natural gas mixtures, and other carbon-free hydrogen-containing fuels. The projects will study combustion issues in combined and in simple cycle applications.
The National Energy Technology Laboratory (NETL) will manage the projects. The FOA will seek to fund laboratory/bench-scale R&D in three areas of interest (AOIs):
AOI 1: Hydrogen Combustion Fundamentals for Gas Turbines. Research undertaken in this AOI will study the fundamental combustion phenomena of hydrogen-containing fuels, over a broad range of fuel compositions and combustion conditions.
R&D subjects of interest for AOI 1 include:
Assessment of ignition energy and delay times;
Assessment of autoignition characteristics;
Assessment of laminar and turbulent flame speeds;
Assessment of extinction strain rates;
Collection of chemical reaction kinetic data and development of reaction mechanisms;
Evaluation of pollutant (Oxides of nitrogen (NOx), CO, and particulate matter) formation and formation pathways, including the impact of ammonia and diluents on pollutant formation;
Development of computational fluid dynamic (CFD) models, computational reaction models, and other design tools to support applied hydrogen containing fuel combustion experiments; and Assessment of fuel mixing characteristics.
AOI 2: Hydrogen Combustion Applications for Gas Turbines. The goal of this AOI is to study hydrogen-containing fuel combustion phenomena under various gas turbine conditions. The research could be used to design stable, high-temperature, and low-emission gas turbine combustors for hydrogen-containing fuels.
Under AOI 2, the R&D subject of interest is the assessment and mapping of hydrogen-containing fuel combustion phenomena over a range of relevant gas turbine conditions and physical features, with the goal that the applied understanding would support the design of high temperature and stable hydrogen fueled gas turbine combustion systems with low NOx emissions. Accordingly, applications must consider the following:
Fuels of interest include 100% hydrogen, carbon-free hydrogen-carrying fuels (i.e., ammonia), and mixtures of these fuels with each other and as appropriate with natural gas. Applications should specify these blends to extend and complete, where needed, the known hydrogen-natural gas mixture data set for the relevant gas turbine conditions. Hydrogen and natural gas percent-by-volume mixtures suggested for study should support, but not be limited to, likely gas turbine deployment scenarios with hydrogen fuels.
The hydrogen-containing fuels combustion assessment must consider test conditions and physical features (injectors, injector interactions, burners, swirlers, bluff bodies, vanes, etc.) representative of existing combustor designs, new combustor designs, and retrofit applications. Unique and novel approaches for purpose-built features made possible through advanced manufacturing to realize the goal of AOI 2 are encouraged.
Diluents available for air-breathing, open combustion Brayton cycles in simple and combined-cycle applications should be used in testing, and the impact of diluents should be assessed. Nitrogen may be used as a diluent when assessing ammonia or ammonia-mixtures as a fuel. Nitrogen may be used to assess combustion phenomena; however, nitrogen is not considered to be a diluent that is readily available in most simple and combined-cycle applications for AOI 2.
Several hydrogen-fueled gas turbine flame phenomena of interest include lean blow off, flame extinction limit, flammability limits, combustion instability, flash back, flame holding, flame speed, hot spots, etc.
Assessment of hydrogen fuel air premixing and hydrogen fuel staging particularly for NOx control under relevant conditions and geometries.
Where pertinent, assess conditions relevant to turn-down range, dynamics, and load-following transients.
AOI 3: Hydrogen-Air Rotating Detonation Engines. This AOI aims to replace the existing deflagration combustion process with detonation, utilizing rotating detonation engines (RDEs) to increase the total pressure at the exit of the combustor and boost thermodynamic efficiency.
AOI 3 has two main focus areas related to RDE combustion and ultimate integration with turbomachinery for the purpose of terrestrial-based power generation while operating on a broad range of hydrogen-based fuels to include pure hydrogen and hydrogen / natural gas mixtures in air. Applications under AOI 3 must address both of these focus areas.
The first focus is to address fundamentally, through a combination of experimental and computational studies, the influence of various loss mechanisms (such as secondary combustion through deflagration or non-detonative shock waves) and wave mode / number on the potential work output from an RDE-turbine system. Testing should consider hydrogen (or hydrogen/natural gas mixture)-air-fueled RDE operations over a broad range of mass flow rates, (pre-detonation combustor) pressures and temperatures relevant to F-class and aeroderivative gas turbine engines. Successful projects must also consider optimal wave mode and wave number configurations to maximize the potential to do useful work in an RDE-turbine system.
The second focus will consider the integration of RDE’s/RDC’s with turbomachinery. For near-term land-based power generation applications, pressure gain combustion devices will be required to efficiently integrate with both upstream and downstream turbomachinery. To date, there have been few studies that have considered the impact of integration beyond cycle analysis.
In an effort at the Air Force Research Laboratory that was jointly funded by NETL, a Rotating Detonation Combustor operating on H2-air was coupled to the turbine of a T63 engine. While this study suggested much of the unsteady nature of the flow could be damped, the integration was not optimized for an RDE-turbine system. Further successful demonstration of an RDE-turbine integrated system is necessary to identify potential knowledge gaps. Successful applications will build upon the existing knowledge base in order to demonstrate (experimentally or through a combination of experimental and computational study) the ability to transition the high-speed, unsteady flow from the RDE exit to a downstream turbine.
Under AOI 3, R&D subjects of interest include:
Assessment of the impact of concurrent deflagration in hydrogen-air (or hydrogen blended fuels) RDE’s to produce useful work when integrated into a gas turbine system.
Assessment of wave mode and wave number of hydrogen-air (or hydrogen blended fuels) RDE’s/RDC’s potential to produce useful work when integrated into a gas turbine system.
Development of computational studies in support of integrating RDE’s and gas turbine systems operating on hydrogen containing fuels and air.
Demonstration of coupling of RDE/RDC with flow transition elements (i.e., diffuser) and turbine.
Demonstration of methodology for quantifying the impact of RDE, transition element(s) and turbine on individual component performance and ability to produce useful work in a gas turbine system.
Suggested methodology for scaling lab-scale experimental and computational studies to F-class and aeroderivative class RDE-gas turbine integrated systems.