Study On The Degradation Characteristic Of Novel Photoreactor And The Distribution Of Light Intensity

A novel labyrinth flow bubble photoreactor (LBPR) was designed. With material balance calculation combining the dynamics equation of photo catalytic reaction, a multi-level serial LBPR reactor mathematic expression was established to describe the relations between the final conversion rate with the number of plates and the heights of liquid exports. The influence of the plates, the heights of liquid exports, liquid rate, liquid volumes, light intensity and catalyst were calculated by the mathematic model. Taking activated carbon of 30-40 meshes as the carrier, TiO₂ photocatalysts were prepared by sol-gel method. The methyl orange wastewater was degraded in a (LBPR) reactor. The number of baffle plate, the height of liquid exports and other structural parameters influenced the degradation performance. In the operating condition of flow rate value was 0.0111m³Â·h^-1, and 4.8g·L^-1 catalysts, when it was degraded about 1.5h, the experiment results showed that the degradation rate can reach to 100% with 12 plates, on 4cm liquid export. The calculations of the model are consistent with the experimental results.The distribution and fluctuation of the light intensity in a liquid-solid and three-phase fluidized bed are influenced by the fluid flow under the illumination of external parallel light. The mathematical models of the light intensity distribution in liquid-solid and three-phase flat fluidized beds are established based on the Lambert-Beer law. The light intensity is attenuated along the lateral distance in the fluidized bed and the influence of the gas holdup, liquid holdup, the specific absorbance of gas and solid on the distribution of light intensity is analyzed. The light intensity signals are measured using a fiber sensor made in our laboratory and the calculation of the model is consistent with experimental results. The analysis about the fluctuating signals shows that the PSD (power spectral density) is attenuated regularly from the low frequency to the high frequency in the liquid-solid fluidized bed, the PSD undulates because of the bubbles in the three phase fluidized bed and the peaks occur at 5-12 Hz, which is coincident with the frequency of bubbles. The model can be easily extended to other light sources and other types of fluidized bed photoreactor.The mathematical models of the light intensity distribution in three-phase annular fluidized bed were established by treating light as photons fluid and combining with the Lambert-Beer laws. The influence of the absorption of the solid catalyst, the methyl orange, the mass of catalyst and the reaction time on the distribution of the light intensity were analyzed. With material balance calculation combining the dynamics equation of photo catalytic reaction, a reactor mathematic expression was established to describe the relations between the final conversion rate and the reactor time. The influence of the liquid rate and the mass of catalyst were analyzed. TiO₂ powder was fixed on activated carbon by the sol-gel method, forming fixed TiO₂ catalyst. The methyl orange wastewater was degraded in annular fluidized reactor. The distribution of the light intensity was measured using fiber sensor made in our lab to prove the math model. The result showed the light intensity was attenuated in the lateral distance. The light intensity became higher as the reactor time increased, lower as the mass of the catalyst increased. The analysis about the fluctuating signals shows that the PSD undulates because of the bubbles in the three phase fluidized bed. The degradation characteristics were studied in different operating conditions; the results showed that the optimum flow rate value was 15L·min^-1 of the gas rate and 290mL·min^-1 of the liquid rate, respectively. The removal rate of methyl orange could almost reach 100%. The calculations of the model were consistent with the experimental results.