Dynamic capacity of desiccants based on modified alumina at elevated pressures

Alumina desiccants obtained by extrusion molding of plastic pastes based on pseudoboehmite or bayerite-containing hydroxides including those modified by sodium and potassium ions were studied. The hydroxides were synthesized by hydration of the product of centrifugal thermal activation of gibbsite under mild conditions. The physicochemical and structural-mechanical properties of the desiccants (fresh and after nine adsorption–regeneration cycles) were studied. The dynamic capacity was determined at a pressure of 3MPa under conditions designed to model the industrial conditions. The sample obtained from bayeritecontaining hydroxide had a higher dynamic capacity than the sample obtained from pseudoboehmite-containing hydroxide at close texture and strength characteristics of adsorbents. Modification of the samples obtained from pseudoboehmite-containing hydroxide with potassium and sodium ions leads to decreased granule stability and increased volume, average pore size, and dynamic capacity. The potassium-modified sample of the desiccant had dynamic capacity as high as that of the sample obtained from bayerite-containing hydroxide at low load. After the cyclic tests, the phase composition, alkaline impurity contents, specific surface area, and crushing strength of the samples did not change within the error of determination. It was found that the prepared desiccants were highly stable in many adsorption–desorption cycles and the minimum dew point of –80°C could be reached during the drying.     

Motion of Trains of Vortex Rings

A numerical experiment on investigation of the dynamics of the interaction of three coaxial vortex rings formed from thermics is performed. As a mathematical model of the phenomenon, the system of Navier–Stokes equations for a compressible heatconducting gas in a cylindrical coordinate system is chosen. The calculations are performed using a finitedifference method based on an explicit threestep scheme of splitting by physical processes. The influence of the position of the thermics on the common axis of symmetry on the character of their motion and interaction is investigated.     

Catalytic synthesis of a stabilizer for industrial oils

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 7, pp. 10–11, July, 1990.     

Mechanisms of micro-macro energy exchange and dynamic strength of solids

Two kinds of steel—30CrNi4Mo armor steel and austenitic 04Cr20Ni6Mn11Mo2NVNb (nitrogen) steel—have been taken for comparative experimental studying a shock-wave behavior under uniaxial strain conditions. For the first kind of steel, transferring energy from load to deformed body is found to be realized through intermediate structural scale (mesoscale), whereas for the second kind—directly, i.e. with-out intermediate scale level.     

Analyzing Biomass Conversion into Liquid Hydrocarbons

Variants of the Fischer–Tropsch producer-gas conversion into liquid hydrocarbons are analyzed under the assumption that thermodynamic equilibrium is attained in the reactions occurring in the biomass gasification. When the raw material is wood waste, the optimum variant of the process involves partial biomass oxidation by atmospheric oxygen with tail-gas recycling after the separation of liquid hydrocarbons. Before mixing with fresh producer gas, the hydrocarbons contained in the tail gas are reformed on a nickel catalyst.