A Comprehensive Approach to Investigating Fluorine-Bearing Gas Mixtures

 An integrated method is proposed for examining the compositions of fluorine-bearing gaseous mixtures, which allows for determining the concentration of HF, F2, N2, O2, CO2, CF4, and C2F6 in these mixtures. The concentration of hydrogen fluoride is determined by its sorption on sodium fluoride followed by the determination of the fluoride ion by the potentiometric method. The lower threshold of determination of hydrogen fluoride is found to be 0.09 vol.%. The concentrations of N2, O2, CO2, CF4, and C2F6 are determined by the gas chromatographic method using a thermal conductivity detector. The proposed gas-chromatography method offers a quantitative measurement of the concentration of N2, O2, CO2, CF4, and C2F6 at the lower limits of detection of 0.008, 0.012, 0.011, 0.009, and 0.019 vol.%, respectively. Based on the developed method, the compositions of a standard fluorine-nitrogen (10 vol.%) and anodic gas samples, synthesized in a laboratory electrolyzer at the National Research Tomsk Polytechnic University and in an industrial electrochemical reactor at JSC Siberian Chemical Plant (Russia), are studied

Ultradispersed Electro-explosive Iron Powders as Catalysts for Synthesis of Liquid Hydrocarbons of CO and H[2]

Catalytic activity of ultradispersed iron powders (UDIP) obtained by electric explosion of the conductor in media of nitrogen, carbon monoxide, and carbon dioxide in synthesis of liquid hydrocarbons by Fischer-Tropsch method was studied. It was shown that iron powder obtained in media of CO[2] has the highest specific surface area. A sample of powder was pelletized at pressure of 21 MPa during 30 seconds with use of 10 mass% polyvinyl alcohol as adhesive for experimentation in catalytic system. Catalyst fraction of 1-2 mm was selected for study. The experiments were carried out under conditions of 1 MPa, 300 mln/min of total reactants consumption, and varied values of temperature and reactants ratio. The maximal conversion level of CO was reached at 290°С and reactants ratio of H[2]:CO=2 in the initial mixture. It was shown that UDIP has high activity at lowered concentration of hydrogen in the initial mixture. The obtained mixture of liquid hydrocarbons is applicable for further refining for upgrading and improving of operating features

Acidic and Catalytic Properties of Mo-Containing Zeolite Catalysts for Non-Oxidative Methane Conversion

The conversion of methane into benzene, toluene and naphthalene at the reaction temperature of 750 В°C and gas hourly space velocity (GHSV) of 500-1500 h-1 over zeolites modified via impregnation with ammonium heptamolybdate and mechanical mixing with Mo oxide and nanopowder is studied under non-oxidative conditions. It has been established that the highest methane conversion per one run and maximal yield of aromatic hydrocarbons are reached for the sample containing 4.0 mass.% the Mo nanopowder. The stability of Mo-containing zeolite catalysts in the process of methane dehydroaromatization at different GHSV has been studied and a characteristic presence of the induction period caused by the formation of active Mo forms both on the external surface and into the zeolite channels has been established. Both the duration of induction period and stable catalyst operation are decreasing with increasing of GHSV. It was demonstrated that acidic properties of a Mo-containing zeolite catalyst depend on the Mo concentration and method of its introduction