An investigation of ammonia primary flame combustor concepts for emissions reduction with OH*, NH2* and NH* chemiluminescence at elevated conditions - data

Data comprises optical an experimental data captured throughout the experimental programme, and accessible in two formats:

Captured emissions data is presented in a spreadsheet. This is comprised of flow data for each experimental condition, with relevant units presented, alongside the data captured from each emissions analyser for that condition. The data have been normalised to equivalent dry 15% O₂ conditions.

Optical data is also presented for each relevant condition. This is given in the form of a numerical array, corresponding to averaged/deconvoluted chemiluminescence pixel intensity, and will need to be viewed using a numerical program e.g. MATLAB. The naming convention is as follows:

Test point_Date_Fuel type_Equivalenace ratio_tempterature point_chemiluminescent species

Further information about each experimental condition can be found in the paper, available 'Green' open access, with the abstract provided below:

With developing interest in NH₃ as a prospective energy carrier, combustor designs and fuelling concepts require optimisation to reduce NO_x emissions. Through the introduction of staged combustor concepts, pathways have previously been identified that limit NO_x production whilst improving combustor efficiency and reducing unburned NH₃. However, the efficacy of secondary air staging is sensitive to the primary flame behaviour, and whilst low NO_x emissions can be achieved at rich conditions, high unburned NH₃ leads to greater global NO_x concentrations from downstream production. Here, time-resolved OH*, NH₂* and NH* chemiluminescence were employed together for the first time for NH₃-air and NH₃H₂-air flames to investigate a primary flame configuration that produced the lowest combined emissions concentration. A generic, fuel-flexible burner was developed to enable partial and full premixing, together with operation of a swirl-stabilised non-premixed flame. Initially, NH₃H₂-air flames were employed in a range of configurations and produced markedly different chemiluminescence and emissions results as functions of global equivalence ratio. The performance of a pure NH₃-air flame was subsequently investigated and compared to the blended fuel results. Optical trends complemented changes in sampled exhaust emissions, enabling analysis of intermediate chemistry. Burner inlet temperature and pressure were then increased proportionally to maintain equivalent bulk nozzle exit velocities. Contrasting trends were identified as functions of fuel composition and equivalence ratio, with a comprehensive database of optical and analytical results generated. Results obtained for NH₃H₂-air suggest the most favourable configuration resulted from a partially premixed flame employing H₂ as a pilot, operating under rich conditions (Φ=1.2). However, at higher temperatures and pressures, the trends observed for non-premixed NH₃-air flames will lead to superior performance, particularly with a small increase in equivalence ratio.

Research results based upon these data are published at https://doi.org/10.1016/j.proci.2020.06.310