As energy appetites around the world continue to grow, hydrocarbon fuels will continue contributing to the energy portfolio for the foreseeable future. At the same time, concerns about climate change have increasingly motivated development of energy sources that contribute less to atmospheric carbon levels. Use of supercritical carbon dioxide (sCO2) in modern power cycles has grown in recent years, since the carbon dioxide-rich fluid allows for improved thermodynamic efficiency, more compact facilities, and impressive reductions in cost compared to supercritical steam cycles. As a result, sCO2 power cycles have seen increased evaluation for deployment in a variety of applications, including the complex process of combustion.
A full combustion reaction can easily consist of hundreds of species with thousands of reactions, causing a complete combustion mechanism to be too complex for high fidelity simulations. Even the simplest combustion reactions include a large number of short, transitional steps that produce intermediate species. Once an intermediate species has been produced, it can interact with its environment and any present impurities to produce soot and other undesired substances, affecting the entire power cycle. Combustion simulations are thus used to predict not only energy release, but the effects of pollutants.
Since full mechanisms cannot feasibly be integrated into a full-resolution, time-intensive computational fluid dynamics (CFD) simulation, development of a fast-running approach that includes more effects of flow mixing and turbulence will add substantial value to the sCO2 combustion kinetics community. The goal of this effort is to develop accurate, experimentally validated, reduced chemical mechanisms for oxy combustion in supercritical carbon dioxide-rich environments. During the design, evaluation, and deployment of sCO2 cycles, modeling and simulation activities are carried out alongside experimental studies to support safe, economically optimized design and operation. The chemical kinetics models developed through this effort will not only provide insight into combustor-specific design areas but will inform the overall design of components for sCO2 cycles for which stream purity is important.
