Performance of cracked ammonia combustion in a gas turbine engine - Evaluation through CFD and chemical reactor network modeling
Typ
Examensarbete för masterexamen
Program
Sustainable energy systems (MPSES), MSc
Publicerad
2022
Författare
Lindfors, Johanna
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The issue of global warming and the increasing global energy demand requires introduction
of new, renewable fuels for energy- and electricity production. If generated
from green hydrogen, ammonia could be of particular importance in future sustainable
energy systems as an energy carrier and a carbon free gas turbine fuel. Opposed
to hydrogen, transportation and storage of ammonia is already widely established
and easily facilitated; however, the combustion properties of pure ammonia are not
feasible with a turbulent gas turbine environment due to low reactivity. By partially
cracking ammonia into its elementary components, suitable combustion properties
can be obtained. Ammonia combustion is also prone to substantial levels of NOX
and N2O emissions. However, adoption of rich-lean staging has previously been
shown to mitigate NOX emissions from the combustion process. In this thesis, the
combustion performance of cracked ammonia in the SGT-750 gas turbine combustor,
provided by Siemens Energy AB, is evaluated in terms of emissions and
ame
stability. Numerical CFD and chemical reactor network (CRN) models are used
to investigate the feasibility of di erent fuel compositions, originating from cracked
ammonia, as gas turbine fuels. Equivalence ratios ranging from approximately 0.4 to
1.5 are investigated, in single stage and air-staged combustion. The results revealed
that
ame stability was achievable for ammonia cracking degrees of at least 40%
at lean conditions, and NOX emissions below 100 ppmvd were emitted for rich-lean
staged combustion. Global warming potentials, as CO2-equivalents, far below those
of conventional natural gas combustion were found for several fuel compositions and
equivalence ratios. However, great discrepancies were apparent among the resulting
N2O emissions from the di erent models. Thus, further experimental validation of
the applied computational models and chemical mechanism is required, to establish
the environmental performance of cracked ammonia as a gas turbine fuel.
Beskrivning
Ämne/nyckelord
CFD , CRN , ammonia , hydrogen , gas turbines , combustion , NOx , N2O