| Interior space is the main place of the people’s life, indoor air quality plays an important part in human health. Researchs found that volatile organic compounds are the main substances that cause indoor pollution. Benzene is one of the common indoor volatile organics, which has strong toxicity.Therefore, reducing the concentration of the benzene in indoor air has an important meaning.In this paper, chitosan was used as crosslinking agent to the nanocomposite titanium dioxide/carbon nanotubes, which was made by sol-gel methods, to prepare the titanium dioxide/carbon nanotubes/chitosan film. The film, of which composition, structure, morphology and the absorption performance of light was analyzed by fourier infrared spectroscopy(FT-IR), X-ray diffraction(XRD), transmission electron microscopy(TEM) and UV-visible diffuse(UV-vis), was used to remove indoor benzene pollutant. In order to study the performance of the new catalyst, the comparison was carried out with the catalyst titanium dioxide (P25)/chitosan in the same experimental condition.This paper adopted research methods including experiments and CFD modeling to study the kinetic process of photocatalytic degradation for VOC.In this paper, Langmiur balance adsorption model was adopted and L-H dynamics equation was used to describe the degradation of catalytic reaction process. This paper described the experiment process and control steps of flat plate reactor degradation. The data of pollutant concentration values (Cin and Cout), which were obtained from of entrance and exit of the reactor, were fitted to get the reaction rate constant.FLUENT is a frequently-used CFD numerical simulation software, by running discrete calculation of the control equations, it enable people to get the data in the required computational domain such as velocity field, temperature field, concentration field, speed, temperature and density. So the FLUENT software was used in this paper to study the photocatalytic degradation reaction in the photocatalytic reactor. And then the laminar model was chosen to express the moving of the polluents. In order to illustrate the source of the convection-diffusion equation, an user-defined function (UDF) was adopted to programme the reaction process. In order to calculate the light intensity in the reaction face, the LSSE irradiation model was utilized.In this paper, the simulation processes of FLUENT we analyzed in detail. These processes are the meshing of the photocatalytic reactor, the governing equation in the FLUENT and UDF program. GAMBIT software was adopted to get the mesh of photocatalytic reactor. There was a detailed description of the control equations and the programming process of UDF as well as an analysis of the light intensity in the reaction face, which was calculated by the LSSE irradiation model. As a result, the appropriate distance between the illuminant and the reaction face was obtained. Finally, the velocity field and concentration field which were calculated by the FLUENT were derived. Through the analysis of the velocity field and concentration field, it was found that the distribution of the velocity and the concentration calculated from the simulation are almost the same as which from the experiment. Fitted the value from the software simulation, the reaction coefficient was obtained, after comparing it with the value which was obtained from the experiment, it was found that the two values are nearly the same, which also proved it was a right decision to choose FLUENT model. At the same time, because of reaction by UDF program for programming, showed the amount of benzene which was degradated by the reaction surface.So, just change the boundary conditions, this model can be suitable for different pollutants and different reactor, suitable scope has been widespread. |
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