Investigation On Hydrodynamics And Resistance Characteristics Of 3D Nets Based On Full Spectrum VOCs Degradation

At present,the problem of volatile organic matter pollution is becoming increasingly serious,which has attracted the attention of all countries.Photocatalytic oxidation technology has become the frontier technology of VOCs treatment at home and abroad because of its great advantages.However,most photocatalytic oxidation technologies today are irradiated by ultraviolet light,which makes the utilization rate of visible light low.Therefore,in this paper,a full spectral VOCs degradation scheme is proposed.The numerical simulation and experimental study on the hydrodynamic behavior and resistance characteristics of 3D nets based on the full spectral VOCs degradation are carried out.At the same time,visible light photocatalyst（Bi₂O₃）was assembled with metal wire,and the intermittent experimental study about the photocatalytic oxidation VOCs degradation is carried out.The numerical simulation of flow field and resistance characteristics in 3D wire net is carried out by FLUENT software.The influence of different airflow parameters and structural parameters on the resistance characteristics is obtained.With the increase of the inlet velocity,the pressure drop of the 3D nets increases gradually and shows the regular change of near quadratic curve.But the pressure drop in general is small.When the gas flow velocity is low,the increase of the diameter of the wire has little effect on the three-dimensional screen pressure drop.Howerver,when the gas flow velocity reaches a certain value,the pressure drop of the three-dimensional screen increases with the increase of the diameter of the wire.This is for this reason that a large number of micro swirl will be produced when the gas flows through the three-dimensional screen,which dissipates the energy and increases the pressure drop.A pressure drop measurement experiment device of 3D nets is established,and experimental study of its resistance characteristics are carried out.The results showed that the error between the measured pressure drop data and the numerical simulation results was within the allowable range of the engineering application,which verified the reliability and accuracy of the numerical simulation method.In addition,the number of layers increases,the pressure drop of the 3D nets increases gradually.When the inlet velocity is 5 m/s,the pressure drop of the multi-layer net is almost the superposition of the single layer net pressure drop.But when the inlet velocity reaches10 m/s,the pressure drop will only increase about 30 Pa.The visible light photocatalyst（Bi₂O₃）is assembled with metal wire by powder sintering method,and benzene and toluene are used as treatment objects to conduct the experimental study on the VOCs degradation by full-spectrum photocatalytic oxidation.The results showed that the degradation rate of benzene and toluene decreased with the increase of initial concentration,and increased with the prolongation of illumination time.Under the same conditions,the degradation rate of toluene is higher than that of benzene.