An innovative Concept for the complete and low-NOx Combustion of non-carbon Eco-fuels using a thermo-acoustically-driven, hydrogen-powered Pilot Stage

The problem of climate change, triggered by a high concentration of pollutants in the atmosphere and the scarcity of fossil resources, increases the need of low emission thermal utilisation of novel, non-carbon eco-fuels such as hydrogen, ammonia (both for energy and propulsion) or hydrogen sulphide (sulphuric acid production). While all of these listed eco-fuels have the potential to decarbonise industry and the energy sector, they also pose demanding challenges regarding combustion. To address these challenges the consortium consisting of Combustion Bay One e.U., P&P Industries AG and FH JOANNEUM GmbH is working on the project called BLUETIFUEL, supported by the FFG. The idea of BLUETIFUEL is to combine the advantages of current low-NOx technologies in terms of ultra-lean combustion with a precisely controlled, forced flame turbulence generated by a pulsation apparatus. The aim of the project is to develop a safe and highly digitalised combustion technology for the complete and low-NOx combustion of hydrogen, ammonia and hydrogen sulphide, including a three-staged burner design for application in the megawatt range with multi eco-fuel capacities and a fully automated control loop for the combustion process. In this paper the project BLUETIFUEL is introduced including its vision and strategy. This is followed by a detailed explanation of the principle, new features and improvements of the pulsation apparatus called Siren E, especially designed for the industrial use. Furthermore, a method and its implementation for detecting eigenfrequencies of the flame by using Siren E and an acoustic sensor are presented. Afterwards, a detailed description of initial combustion experiments and their test setup is given. The experiments were performed with hydrogen up to a thermal power of 7.5 kW. First, different methods for the injection of hydrogen were tested in terms of their combustion stability and flashback tendency. Then, their response to thermo-acoustic excitation via loudspeaker and Siren E was investigated, resulting in a prioritised premixing variant. This is followed by the discussion of the early results out of non-reactive and reactive CFD simulation and the experiments with hydrogen, leading to the conclusion of this paper.