Session: 04-14 Combustor Design II

Paper Number: 152946

Coupling Micro-Mixing Combustion With a Pre-Reactor Operating Under Ultra-Rich Conditions for Low-NOx Combustion of Hydrocarbons 

While hydrogen is sought as the fuel of the future for power generation gas turbines, hydrocarbons such as SAFs are still expected to be prevailing in the aeronautical field. Nonetheless, reduction of pollutant emissions from combustion, especially NOx, is one of the main ongoing challenges. Wide operability range and safe combustion requirements in the aeronautical field limit the use of premix combustion to reduce NOx emissions. Other NOx reduction strategies, like water dilution, are also unsuitable because of the context of an aircraft. Therefore, because of those limitations, there is a need to develop strategies to lower NOx emissions in the aeronautical field.

Micro-mixing combustion is promising because of its non-premix like combustion while having the potential to achieve NOx emissions near premix levels due to the mixing of fuel and air at the smallest scale possible. However, micro-mixing combustion is principally suited for hydrogen and natural gas. Based on our previous work, the heavier the hydrocarbons are, the less performant is micro-mixing combustion because of the increase of the mixing timescale, which leads to higher thermal NOx productions. Consequently, there is a need to achieve faster mixing with heavy hydrocarbons to allow their pairing with micro-mixing combustion.

This paper presents an experimental proof-of-concepts of a combustor architecture composed of a micro-mixing injector coupled with a reactor operating under ultra-rich conditions. Air is introduced in the fuel at a high equivalence ratio, between 15 and 25, and the reaction is activated with the heat of the combustion. The thermally coupled reactor forms lighter species from heavy hydrocarbons through partial oxidation of the fuel balancing the effects of heavier fuels. This concept is more advantageous the heavier the fuel is because of the gap in the density between the fuel and the product of the reactor.

Experimental tests with propane at atmospheric pressure, and at adiabatic flame temperature between ~1500K and ~2000K, were performed to demonstrate the concept. NOx emissions were reduced by a factor up to 3 with this combustion architecture compared to baseline tests, achieving near premix NOx emissions. Increasing the air injected in the reactor decreased further the NOx emissions. Additionally, tuning of the combustion stability was possible by adjusting the reactor parameters.

Presenting Author: Xavier Bellavance Université de Sherbrooke

Presenting Author Biography: Xavier Bellavance is a PhD student in the Createk Design Lab of the University of Sherbrooke, working on micro-mixing combustion. He is also working on the integration of refractory metals in the design of micro-mixing injector in the Shape Memory Alloys and Intelligent Systems Laboratory (LAMSI) of the École de Technologie Supérieure (ÉTS).

Authors:

Xavier Bellavance Université de Sherbrooke
Alexandre Landry-Blais Université de Sherbrooke
Jean-Sébastien Plante Université de Sherbrooke
Mathieu Picard Université de Sherbrooke