Quantitative imaging of KOH vapor in combustion environments using 266 nm laser-induced photofragmentation fluorescence

In biomass thermal conversion processes, the release of potassium in high temperature environments crucially influences operating efficiency and safety. The dominant species can be hydroxide (KOH) and/or chloride (KCl). We report a species-specified quantitative measurement combustion using laser-induced photofragmentation fluorescence (LIPF). Ultraviolet (UV) light sources with different wavelengths (193, 213 266 nm) were investigated to select proper source ensuring that excited atoms 4 2 P state could only generated from KOH molecules, not another major compound, (KCl), emit at 766/769 nm after photodissociation. After direct comparison, fourth-harmonic Nd:YAG laser was found most source. signal strongly influenced by as molecules thermally populated vibrational levels needed produce photolysis. calibration broadband UV absorption spectroscopy, detection limit LIPF planar imaging system determined about 3 ppm 1750 K under harsh condition, where 80% re-absorbed present background gas. technique applied quantitatively measure concentration hot flue gasses provided carbonate seeded flames varying equivalence ratios, it also used visualize distribution vapor above piece burning wood char.