Dry Low NOx combustion of hydrogen-enriched fuels at high-pressure conditions for gas turbine applications
The capability for gas turbines to operate on hydrogen-based fuels is a key future requirement to fulfil the target of CO2-free power generation. Currently, the maximum volumetric hydrogen fraction, up to which commercially available gas turbines can be operated with, lies between 30% and 50% depending on the specific gas turbine class and type. Ongoing H2020 projects (HYFLEXPOWER[[https://cordis.europa.eu/project/id/884229]], FLEXnCONFU[[https://cordis.europa.eu/project/id/884157]]) are focusing on power-to-gas-to-power technologies and partly also address hydrogen combustion in gas turbines. They are focussing on the whole power-to-gas-to-power system and hence either on small GT sizes (12MW in HYFLEXPOWER) or target to demonstrate small hydrogen fractions (FLEXnCONFU). Consequently, significant technological advancements in the gas turbines’ combustion systems are required to further reduce and ultimately eliminate natural gas from the fuel blend.
The peculiar thermodynamic and combustion properties of hydrogen (e.g. diffusivity, reactivity, flame speed etc.) pose new challenges towards the achievement of a stable combustion process. These challenges are greatly increased for hydrogen combustion at the high-pressure conditions, which are relevant for gas turbine operation.
The scope of this topic is to design and demonstrate in relevant environment a scaled and full-size combustion system, i.e same geometry and fire power as finally installed in the gas turbine. It is expected that experimental investigation will be performed up to full-load condition at least on a single burner of the gas turbine, including the monitoring and control in case of new combustors as well as for retrofits. These combustion systems should be capable of operating at full gas turbine pressure conditions with any concentration of hydrogen admixed with natural gas and focus on volumetric hydrogen contents between 70-100%, i.e. well beyond the capability of state-of-the-art commercial gas turbines.
Activities are expected to start at TRL4 and should foresee the necessary laboratory experiments and numerical modelling leading to the design and validation of a full-size combustion chamber. At the end of the project duration, the proposed and developed solutions should achieve TRL6 and be validated in a relevant environment.
In order to achieve the expected outcomes, the development of the combustion system development should have in mind the following constraints and present solutions to overcome the associated technical hurdles:
- Stable combustion properties of hydrogen-rich flames demonstrated in full-scale combustor hardware at high pressure gas turbine conditions and across the entire GT load. This includes static (no flame flashback) as well as dynamic stability (no thermo-acoustic instabilities)
- Ensure sufficiently high firing temperatures to maintain high cycle efficiency of the respective gas turbine class.
- Ensure ultra-low emissions of air pollutants, in particular those of nitrous oxides (NOx)
- Development of solutions for a combustion system that is capable to overcome previously mentioned technical challenges without the use of diluents (e.g. nitrogen, steam dilution, etc).
Consortia are expected to include turbine manufacturers. It is also encouraged to seek the involvement of plant operators. In addition, proposals should demonstrate that they will have access to the infrastructure that will be necessary to undertake the full-size testing.
As there may be different means to address the aforementioned technical hurdles, the specific research activities should be clearly detailed in the project proposal. Preferably the topic will support complementary approaches for small to medium power industrial gas turbines (above 12 MW electric) and large heavy-duty gas turbines (above 200 MW electric).
Activities are expected to start at TRL 4 and achieve TRL 6 by the end of the project.
The conditions related to this topic are provided in the chapter 2.2.3.2 of the Clean Hydrogen JU 2022 Annual Work Plan and in the General Annexes to the Horizon Europe Work Programme 2021–2022 which apply mutatis mutandis.