ANALYSIS OF GAS-LIQUID-SOLID REACTIONS IN AN ANNULAR PHOTOCHEMICAL REACTOR WITH LIGHT-ABSORPTION

Effective absorption coefficients were evaluated from the observed profile of light intensity in a square column with gas-liquid-solid dispersion containing TiO2 particles (in the range of mean diameter: 16.8 approximately 75.2-mu-m), and those were correlated as a first-order equation of specific surface areas of gas and solid. Quantum efficiencies were obtained from the measured photooxidation rate of NADH (reduced form of nicotinamide-adenine dinucleotide) in a small annular photoreactor and were expressed as a first-order equation of the specific surface area of TiO2. In an annular reactor (outer diameter = 10 cm, inner diameter = 4.6 cm and height = 1 m) with gas-liquid-solid dispersion, photooxidation of NADH was carried out and the observed NADH concentrations with reaction time agreed well with the values calculated from the model of light intensity profile using the effective absorption coefficient.