Investigation of Adjacent Lifted Flames Interaction in an Inline and Inclined Multi-Burner Arrangement

The main objective of this research is to assess an innovative, low nitrogen oxides emission combustor concept, which has the potential to achieve the long term European emissions goals for aircraft engines. Lean lifted spray flames and their very low nitrogen oxides emissions are combined with an inclination of burners in annular combustor leading to a more compact combustor with superior stability range. The presented combustor concept was developed in the frame of the European research project CHAIRLIFT (Compact Helical Arranged combustoRs with lean LIFTed flames). CHAIRLIFT combustor concept is based on “low swirl” lean lifted spray flames, which features a high degree of premixing and consequently significantly reduced nitrogen oxides emissions and flashback risk compared to conventional swirl stabilized flames. In the CHAIRLIFT combustor concept, the lifted flames are combined with Short Helical Combustors arrangement to attain stable combustion by tilting the axis of the flames relative to the axis of the turbine to enhance the interaction of adjacent flames in a circumferential direction. A series of experimental tests were conducted at a multi-burner array test rig consisting of up to five modular burners at different burner inclination angles (0° and 45°), equivalence ratios, and relative air pressure drop at ambient conditions. For all investigated configurations, a remarkable high lean blow out for non-piloted burners (ϕLBO = 0.29–0.37), was measured. The multi-burner configurations were observed having a superior stability range in contrast to the typical decrease in stability from single to high swirl multi-burner. The unwanted flow deflection of highly swirled flames in Short Helical Combustors arrangement, could be avoided with the investigated low swirl lifted flames. Moreover, the flame chemiluminescence (OH*) measurements were used to provide a qualitative characterization of the flame topology. Complementary numerical investigations were carried out using different numbers of burners to evaluate the effect of boundary conditions

Power-to-Gas through High Temperature Electrolysis and Carbon Dioxide Methanation: Reactor Design and Process Modeling

This work deals with the coupling between high temperature steam electrolysis using solid oxide cells (SOEC) and carbon dioxide methanation to produce a synthetic natural gas (SNG) directly injectable in the natural gas distribution grid via a power-to-gas (P2G) pathway. An intrinsic kinetics obtained from the open literature has been used as the basis for a plug flow reactor model applied to a series of cooled multitube fixed bed reactors for methane synthesis. Evaporating water has been considered as coolant, ensuring a high heat transfer coefficient within the shell side of the reactor. A methanation section has been designed and optimized in order to moderate the maximum temperature within the catalytic bed and to minimize the catalyst load. Then, process modeling of a plant coupling high temperature electrolysis and methanation is presented: the main goal of this analysis is the calculation of overall plant efficiency (in terms of electricity-to-SNG chemical energy). Plant size has been set considering a 10 MW_el SOEC-based electrolysis unit; heat produced from the exothermal methanation is entirely used for water evaporation before the steam electrolysis. A heat exchanger network (HEN) has been designed in order to reduce the number of components, resulting in an external heat requirement equal to 185 kW (≈1.9% of the electrolysis power). The SOEC-based power-to-gas system presented a higher heating value based efficiency equal to ≈86% (≈77% if evaluated on lower heating value basis)