The Technical Study Of Deep Desulfurization Of Natural Gas By Nano-TiO₂ Photocatalytic

A series of nanometer titanium dioxide (TiO2) and doped TiO2 were prepared by sol - gel method, in which were doped of transition metal (Fe, Ni, Cu, Zn), rare earth (La, Ce, Eu), precious metals (Ag) and non-metallic (N). The TiO2 film on glass was prepared by dip- -coating method and then it was calcined respectively at 400℃, 450℃, 500℃, 550℃, 600℃, in order to carry through photocatalytic removal sulfide experiment. Characterized by TG-DTA, XRD, BET, UV-VIS, doped TiO2 was in comparison with pure TiO2. The results showed that the performance of doped TiO2 had occurred a marked change: phase change temperature increased, La-TiO2 calcined at 600℃had not yet occurred phase change, phase transitional temperature of pure TiO2 was 500 to 600℃); the size of the particle reduced (calcined at 500℃); doped TiO2 had larger BET surface area; the absorption spectra were shifted to visible redshift (exception of Zn).Using hydrogen sulfide for the target compounds, the effect of different ions, illumination time, doping ion concentration, baking temperature on the performance of the TiO2 photocatalytic desulfurization were studied. The results showed that the optimal volume of doped Fe, Ni, Cu, Zn, La, Ce, Ag and N of TiO2 as photocatalysis respectively was 0.7%, 5.0%, 4.0%, 1.0%, 3.0%, 2.0%, 1.0% and 300% (molar ratio to TiO2). The optimum calcination temperatures of doped Zn, La, Ce and N of TiO2 were 500℃, while the optimum calcination temperatures of doped Fe, Ni, Cu, Ag of TiO2 were 550℃. The desulfurization rate using 0.7%Fe-TiO2 removal sulfide from simulation natural gas, which was closed to 97.3%.Desulfurization reaction in the best conditions, the photocatalytic activity of TiO2 and doped TiO2 oxidatively removal sulfide from natural gas were studied. The results showed that the optimum calcination temperature of doped Fe, Ni, Cu, Ag of TiO2 was 550℃, and the desulfurization rate using 0.7%Fe-TiO2 removal sulfide from natural gas was closed to 93.1%. The optimum calcination temperature of doped Zn(acetic acid), Zn(nitric acid), La, Ce, N of TiO2 was 500℃, and the desulfurization rate of 2.0% Ce-TiO2 removal sulfide from natural gas was closed to 90.2%. The optimum calcination temperature of nano-TiO2 and doped TiO2 used in natural gas was consistent with nano-TiO2 and doped TiO2 used in hydrogen sulfide.