Ammonia–methane combustion in tangential swirl burners for gas turbine power generation

Abstract

h i g h l i g h t sAmmonia can become a new energy vector for large scale power generation. Ammonia fuelled gas turbines have been barely studied. Scarce literature exist. Current research provides findings that show NH 3 potential as gas turbines fuel. Unfortunately, weak flame stability and high emissions are still restrictive. Stratified injection with low swirl might be the best way to use these blends. a b s t r a c tAmmonia has been proposed as a potential energy storage medium in the transition towards a lowcarbon economy. This paper details experimental results and numerical calculations obtained to progress towards optimisation of fuel injection and fluidic stabilisation in swirl burners with ammonia as the primary fuel. A generic tangential swirl burner has been employed to determine flame stability and emissions produced at different equivalence ratios using ammonia-methane blends. Experiments were performed under atmospheric and medium pressurised conditions using gas analysis and chemiluminescence to quantify emission concentrations and OH production zones respectively. Numerical calculations using GASEQ and CHEMKIN-PRO were performed to complement, compare with and extend experimental findings, hence improving understanding concerning the evolution of species when fuelling on ammonia blends. It is concluded that a fully premixed injection strategy is not appropriate for optimised ammonia combustion and that high flame instabilities can be produced at medium swirl numbers, hence necessitating lower swirl and a different injection strategy for optimised power generation utilising ammonia fuel blends.

Experimental and modeling study on ignition delay of ammonia/methane fuels

“…Ammonia–methane/air mixtures tested in the present experiment are presented in Table 1. The mole ratio of ammonia to methane is 60%/40%, which is a feasible ammonia‐based fuel blend for stable combustion as investigated in the work of Valera‐Medina et al 14 Three equivalence ratios, 0.5, 1, 2, were tested to represent fuel lean, stoichiometric, and fuel‐rich conditions. Pressure conditions around 2 atm and 5 atm were investigated in the experiment.…”

“…Although previous work has made a good progress in the utilization and understanding of ammonia combustion, there are still lots of issues which need to be better settled. For instance, fuel conversion efficiency is not high as found in previous ammonia combustion studies, which can lead to extremely high emissions of unburnt fuel and NOx 14,20 . Thus, special treatments are needed to reduce pollutant emissions.…”

“…In terms of utilizing ammonia in combustion equipment, pertinent studies have tested and applied ammonia in internal combustion engines, 10‐12 gas turbines, 13‐15 etc. Meanwhile, in order to support the application and have better understanding of ammonia combustion, fundamental studies also have been performed using ammonia fuels 16‐19 .…”

“…As methane is a popular clean fuel widely used in engine and power industries, 26,27 some researchers explored to enhance ammonia combustion by using methane. For instance, Valera‐Medina et al 14 investigated ammonia/methane fuel blends combustion in a generic tangential swirl burner experiment for gas turbine use. Stable combustion was achieved in the burner with 60%ammonia–40%methane.…”

Clean, efficient and affordable energy for a sustainable future

“…In paper [52], details experimental results and numerical calculations were reported on the optimization of fuel injection and fluidic stabilisation in swirl burners with ammonia as the primary fuel for gas turbine power generation. The results showed that a fully premixed injection strategy is not appropriate for optimized ammonia combustion and that high flame instabilities can be produced at medium swirl numbers, hence necessitating lower swirl and a different injection strategy for optimized power generation utilising ammonia fuel blends.…”