The paper describes a combined approach of bench and pilot scale experiments that is revealing new insights into the complex interactions between chemical reaction and mixing which affect product of incomplete combustion (PIC) emissions and secondary combustion chamber (SCC) performance. The bench scale reactor allows well defined experiments which are relatively easy to control and inexpensive. The pilot scale reactor allows experiments under near-commercial scale SCC conditions. Using its volatile organics sampling train (VOST)-like sampling and gas chromatography (GC) systems, combustion products are analyzed with high sensitivity, but at low costs and short turnaround times.