HYdrogen combustion: Pressure effects On combustion and THErmoacousticS

Project Information

HYPOTHESis

Grant agreement ID: 101019937

DOI

10.3030/101019937

EC signature date 29 June 2021

Start date 1 January 2022

End date 30 June 2027

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 3 096 625,00

EU contribution

€ 3 096 625,00

Coordinated by

TECHNISCHE UNIVERSITAT BERLIN
Germany

Periodic Reporting for period 2 - HYPOTHESis (HYdrogen combustion: Pressure effects On combustion and THErmoacousticS)

Reporting period: 2023-07-01 to 2024-12-31

Summary of the context and overall objectives of the project

HYPOTHESis addresses the urgent need to transition to carbon-free energy sources, focusing on hydrogen as a promising fuel-alternative for gas turbines. Hydrogen is a promising alternative to natural gas because it produces only water when burned, making it a crucial part of future energy systems aimed at reducing carbon emissions. Hydrogen can be produced in a green way from water (via electrolysis) by using renewable energy, and then burned in gas turbines to generate electricity in periods of high-demand. However, its combustion presents significant challenges due to hydrogen's unique thermodynamic properties. These challenges include the high reactivity of hydrogen, which leads to difficulties in safely controlling combustion, the risk of flashback, and the increased production of harmful nitrogen oxides (NOx).

This project is crucial for society as it advances the scientific understanding and technological development of cleaner and more efficient combustion processes, particularly for hydrogen, a promising carbon-free alternative to fossil fuels. By improving the stability and control of hydrogen flames in industrial burners, the project contributes to reducing greenhouse gas emissions by eliminating carbon dioxide emissions, and supports the transition to a more sustainable energy system, addressing both environmental and energy security challenges.

The project's main objectives are to overcome these challenges by developing new technology and scientific knowledge that will enable the safe and efficient use of hydrogen in gas turbines. This includes designing innovative burners that can handle 100% hydrogen with minimal emissions, understanding the behavior of hydrogen flames under high pressure, and creating advanced control methods to prevent combustion instabilities. Ultimately, the project aims to make hydrogen a viable and safe option for clean energy generation, contributing significantly to the global effort to reduce carbon emissions and combat climate change.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The project began by developing two new types of burners, designed specifically to handle the unique challenges of burning hydrogen. The first is a jet burner that stabilizes the hydrogen flame using a high-speed jet of fuel. This design helps to prevent a problem called "flashback," where the flame can move backward into the burner, which is a risk with hydrogen due to its high flame speed. The second burner is a swirl burner that uses a special technique called fluidic actuation to control the swirl of the air and fuel mixture, making it adaptable for both hydrogen and natural gas flames.

During the experiments, the jet burner successfully stabilized flames using different mixtures of natural gas and hydrogen, and even pure hydrogen. The emissions of nitrogen oxides (NOx), which can contribute to air pollution, were kept low across all fuel types, showing the burner’s potential for clean combustion. The team also measured how the flames respond to changes in airflow and fuel concentration (equivalence ratio), which is important for ensuring stable operation and comply with legislation on emissions in real-world conditions. One of the project's innovative approaches was to overcome challenges in measuring the behavior of hydrogen flames. Traditional methods faced difficulties because of hydrogen's different properties compared to natural gas. The team developed new methods to accurately assess how the flame behaves and responds to different conditions. This included adjusting the experimental setup to better mimic the conditions found in actual gas turbines, ensuring that the results are relevant for real-world applications. Additionally, the project focused on preparing for more advanced testing in the future. They successfully built and tested prototypes of the swirl burner and created a high-tech facility at TU Berlin to conduct tests under medium pressure, which more closely resembles the conditions inside a gas turbine.

The HYPOTHESis project has not only produced valuable scientific results but also gained significant recognition in the academic and engineering communities. The team has published several papers and presented their findings at international conferences, contributing to the global effort to develop clean hydrogen technologies. The project's success has also attracted further research funding, and the team is now involved in additional projects aimed at advancing hydrogen as a sustainable energy source.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The HYPOTHESis project aims at pushing the boundaries of what is possible in the field of hydrogen combustion, moving beyond existing technologies and developing new ideas. One of the key challenges with hydrogen is its high flame speed, which can cause dangerous conditions like flashback, where the flame travels back into the burner. To overcome this, the HYPOTHESis team proposed the use of a jet burner, specifically designed to stabilize hydrogen flames using a high-speed jet. This is a significant improvement over conventional swirl designs, which struggle to handle hydrogen safely and effectively. The dynamic response of flames stabilized by high-speed jets is not common in the literature, and it has been characterized within HYPOTHESis. In this respect, the project has also made progress in improving how we measure and understand hydrogen flames. Traditional methods often fall short because hydrogen behaves so differently from natural gas. The team developed new techniques to more accurately assess how hydrogen flames respond to different conditions. In addition, the team created a new type of swirl burner that uses a technique called fluidic actuation. This allows the burner to adjust the swirling motion of the air and fuel mixture without any moving parts. This innovation is particularly important because it enables the burner to adapt to different fuels, including hydrogen, natural gas, and blends of the two. This flexibility is a major step forward, as it supports the transition to hydrogen while still being compatible with existing natural gas infrastructure.

Looking ahead, the HYPOTHESis project is expected to deliver even more groundbreaking results. The novel fluidic swirl burner, now in its final stages of development, and will undergo rigorous testing under conditions that closely mimic those inside a real gas turbine. These tests will help refine the burner’s design and confirm its effectiveness and safety for widespread use. The team will also continue to explore new ways to measure and optimize hydrogen combustion. For example, we are investigating specific light emissions from hydrogen flames that could be used to monitor and control the combustion process in real-time, and we are employing machine learning methods to reduced the number of experiments we need to construct a sufficiently accurate model. These could lead to more efficient and stable operation of hydrogen-burning turbines, making them more viable for large-scale energy production.

Flames stabilized by a high-speed jet burner. The flame shape/size changes significantly with H2%.

Medium Pressure combustion chamber at the Chair of Fluid Dynamics of Prof. C. O. Paschereit.

LDA measurements (left) and final design (right) of the novel fluidic swirl burner of HYPOTHESis.