Quantitative real-time in situ measurement of gaseous K, KOH and KCl in a 140 kW entrained-flow biomass gasifier

Photofragmentation tunable diode laser absorption spectroscopy (PF-TDLAS) was used to simultaneously measure the concentrations of gas phase atomic potassium (K), hydroxide (KOH) and chloride (KCl) in reactor core a 140 kWth atmospheric entrained-flow gasifier (EFG). In two gasification experiments at air-to-fuel equivalence ratio 0.5, EFG first run on forest residues (FR) then an 80/20 mixture FR wheat straw (FR/WS). Combustion 1.3 investigated for comparison. A high K(g) absorbance observed gasification, requiring photofragmentation signals from KOH(g) KCl(g) be recorded fixed detuning 7.3 cm−1 center profile. combustion, fragments recombined instantly after UV pulse within around 10 µs, whereas fragment concentration increased further 30 µs pulse, before slowly decaying up hundreds µs. According 0D reaction kinetics simulations, this could explained by difference recombination kinetics, which is dominated oxygen reactions combustion hydrogen gasification. The K species were stable average, but periodic short-term variations due fuel feeding observed, as well gradual increase over day approached global equilibrium. comparison average towards end each experiment showed higher total FR/WS, with KCl(g), lower KOH(g), compared fuel. measured values reasonable agreement predictions thermodynamic equilibrium calculations.