- Nicholas Worth
- Associate Professor
Carbon-Free Firing of Gas Turbines - SP2
This subproject conducts research and development of gas turbine combustion concepts for hydrogen and ammonia firing, with the aim of achieving a 100% reduction in CO2 emissions from gas turbines. The potential use of these fuels will be investigated through targeted improvements to current combustion technology and the development of new combustion technology.
SP2 aims to advance capabilities for carbon-free firing of gas turbines (GTs) and internal combustion engines (ICEs), to reduce emissions on the Norwegian Continental Shelf. The research methodology in SP2 follows three main tracks:
- In collaboration with Siemens and TU Darmstadt, investigate how to optimize NH3/ H2/N2 blends in order to reduce hydrogen reactivity and provide a potential step-in fuel for natural gas.
- In collaboration with Ansaldo, investigate the GT combustion system handling of hydrogen reactivity preferably without dilution, in order to offer robust aerodynamics that are flashback resistant.
- Investigate the use of ammonia as a hydrogen vector to fuel internal combustion engines (ICEs), by examining injection strategies, ignition, and hydrogen piloting.
MAIN RESULTS IN 2021
- WP1.1 Preliminary quantitative Raman/Rayleigh measurements have been made in NH3 flames at TU Darmstadt, and extinction experiments on a laminar opposed jet burner are ongoing.
- WP1.2 A new PhD candidate joined the project in September 2021 and started planning and design work for the experimental investigation of burner staging strategies in NH3/H2/N2 flames at atmospheric pressure at NTNU.
- WP1.3 An experimental campaign with NH2/H2/N2 fuel blends at pressurised conditions up to 10 bar was conducted. Preliminary results indicate that the favourable pressure scaling effect plateaus beyond 5 bar, but more work is needed to assess the role of the flame structure in this scaling.
- WP2.1 SINTEF and Sandia National Laboratories have conducted the first Direct Numerical Simulations (DNS) of the non- reacting flow fi eld in a simplified Flamesheet-type combustion system geometry.
- WP 3.1 Detailed chemical modelling and simulations are being conducted, which will improve our understanding of ammonia injection and fueling on engine performance, emissions, ignition, and flame structure/ speed. A PhD student is currently conducting a research visit to CERFACS, and preparation for modelling work is underway.
IMPACT AND INNOVATIONS
The research planned in SP2 encompasses technology development and gas turbine combustion chamber optimisation, and ICE novel fueling strategies, and it is therefore particularly well-suited to result in technical innovations.
The novel results in WP1.3 demonstrating the favourable scaling of emissions with pressure indicate the potential feasibility of ammonia blended fuels in practical devices, with the potential for rapid deployment.
- A PhD candidate was hired (NTNU/TU Darmstadt), and an experimental plan was produced for measuring the structure of NH3/H2/N2 flames using Raman/Rayleigh laser diagnostics.
A series of experimental tests have been completed in a scaled SGT750 burner up to 2.5 bar. Key findings included: the stabilisation behaviour of the burner; a favourable emissions performance resulting from different main/pilot splits; and importantly for ammonia blends, a favourable emission trend with pressure was observed.
- Setup and preliminary design and testing work has been completed for the Direct Numerical Simulation (DNS) of the Flamesheet combustor concept, which is a design potentially capable of extreme reactivity of hydrogen blended fuels. Testing confirmed the feasibility of the approach, allowing detailed simulations to be initiated in 2021.
- A series of tests have been completed to prepare for the manufacture of a scaled Flamesheet combustor. These test results will inform the engineering design of the combustor in 2021, allowing this concept to be tested experimentally.
- A PhD student was hired to conduct numerical modelling of ammonia combustion at ICE conditions. Engine mapping based on a stochastic reactor approach is underway, to address the effect of ammonia fuelling on performance and emissions for off shore marine engines applications.
Impact and innovations
The favourable emission trends mentioned above represent a very important result with significant impact for the near-term deployment gas turbines based on ammonia as energy carrier. Inspired by these initial findings, further work is underway to determine if the favourable emission trend continues at even higher (and therefore more engine-relevant) pressures.
Furthermore, the preliminary assessment and application of the DNS methodology to the Flamesheet combustor represents a significant innovation. Such advanced numerical tools, which provide a high formal order of accuracy and fidelity in the representation of the reactive flow, have never been applied before to a geometrically complex configuration such as the Flamesheet combustor concept.
The SP conducts research and develop- ment of gas turbine combustion concepts for hydrogen, and ammonia firing, with the aim of achieving a 100% reduction in CO2 emissions from gas turbines. The potential use of these fuels will be investigated through targeted improvements to current combustion technology and the development of new combustion technology.
The overarching objective of SP2 is to advance the capabilities for carbon-free firing of the gas turbine fleet (existing and future) relevant for deployment on the Norwegian Continental Shelf (NCS). The proposed research approach in SP2 follows two main tracks:
- WP1, NH3/H2/N2 blending: The first track will investigate how to optimize hydrogen blending with opportune carbon-free diluents, such as ammonia/nitrogen, that act to reduce hydrogen reactivity to obtain a step-in fuel for natural gas. This will provide the GT-manufacturer with guidelines for optimal operation and improved design of the combustion system.
- WP2, Flamesheet: The second track will focus on the gas turbine combustion system handling of hydrogen reactivity without dilution, which potentially offers more robust aerodynamics that are flashback resistant.
The main results in 2019 relate to the planning and organization of upcoming experimental and numerical campaigns in the two tracks, in addition to organization activities associated with research collaborations. The following list of deliverables and milestones has been realised:
- A contract has been signed with Robert Barlow, to work collaboratively with TU Darmstadt on fundamental measurements of ammonia/ hydrogen flames structure.
- An experimental plan for SGT750-type burner pressurized combustion testing with ammonia/hydrogen/nitrogen fuel blends has been made.
- An experimental plan for Flamesheet-type burner pressurized combustion testing with undiluted hydrogen has been made.
Impact and innovations
The work in SP2 is not yet at a stage where impact and innovation can be accurately assessed.