Research Of Double-gradient Chloride Dioxide Reactor

The electric heating film of SnO₂: Sb : F was formed by the sol-gel law, and the process conditions of preparing the electric heating film has been optimized: the sol was mixed stannic chloride solution with Sb and F and added the alkali, reaction temperature is 80℃, reaction time is 2 hours, sol pH value is 4.8⁵.0, the method of forming film adopts dip-coating method, drying method adopts step-drying method of 80→50→25℃, sintering temperature is 600℃, sintering time is 2 hours. Surface Resistance, thickness of the electric heat film and generating heat were measured, after dip-coating 18 times, surface resistance of SnO₂: Sb : F is 8 Ω /â–¡ and lower than that of SnO₂: Sb. Experiment shows the contact resistance of the film is close to zero after the film was coated silver electrode through the method of chemical plating. The heating temperature of the film is up to 600℃ and steady in a long-term when the film was putted into circuit.The electric heating film was used for surface's heating medium of reaction tube, the reactor with characteristic of several grades temperature-gradient has been got through adjusting the area of heating medium and change the power of heating and regarded as reactor of chlorine dioxide generator.The reaction liquid in reaction tube formed the reaction condition of double-gradient, which is gradual rise of temperature and gradual fall of concentration. The two phases of gas and liquid coexist in reaction tube. Chlorine dioxide is very steady in the gas even under upper reaction temperature, owing to only the liquid phase was heated, gaseous phase temperature is lower than liquid phase temperature.R5 and Rll techniques were selected for investigate response performance of the reaction tube (NaC103 conversion rate, C1O2 purity and CIO2 output). We investigate influence of liquid velocity of flow, reaction temperature, different consumption of raw materials liquid and reducing agent upon the reaction and optimize the reaction condition.We know from experiment of R5 method, when the concentration of NaC103 was conformed, NaC103 conversion rate is increased with increase of the concentration of HC1, residence time of raw materials liquid in reaction tube and reaction temperature, but which went against advance of CIO2 purity. Comprehensive consideration: raw materials liquid 1 and raw materials Hquid2 were introduced into reaction tube at the same flux, the concentration of NaClC>3 is 3mol/L, the concentration of HC1 is 6^llmol/L, residence time of raw materials liquid in reaction tube is no less than 20 min, the bottom temperature of reaction tube is higher than 80°C, NaClC>3 conversion rate is higher than 90%, the range of C1O2 output is 22.76⁶0.01g/h.We know from experiment of Rll method, when concentration of NaC103 wasconformed The NaC103 conversion rate is also increased with increase of the concentration of HC1, residence time of raw materials liquid in reaction tube and reaction temperature, but which has no influence on CIO2 purity. Comprehensive consideration: raw materials liquid 1 and raw materials Iiquid2 were introduced into reaction tube at the same flux, the concentration of NaC103 is 3mol/L, the concentration of H2SO4 is no less than 8mol/L, the molar ratio of NaClOj and H2O2 is no less than 1 '. 0.6, residence time of raw materials liquid is equal to or less than 20 min, the bottom temperature of reaction tube is up to 80°C, NaC103 conversion rate and C1O2 purity are all close to 100%. The range of C1O2 output is 25.31-60.15g/h.Comparing the best response results of the reaction tube with that of CIO2 generation craft of industry at present, we conclude that the reaction tube has predominance such as The heating rate is quick, The antisepsis ability is strong, The using lifetime is long and so on, furthermore, we has got better response results under lower acidity of response and less consumption of reducing agent inthe condition of reaction tube.