Vol 50, No 4 (2016)

Shanxi anthracite was subjected to oxygen-oxidation at 250°C in all aqueous solution of potassium hydroxide to produce solid benzene polycarboxylic acid (BPCA), and then the BPCA were selectively decarboxylated in the mixed medium of concentrated H₂SO₄ and KHSO₄ to produce crude pyromellitic acid (PA). Pure PA was obtained by solvent recrystallization method, and the best solvent was 2-pentanone. Pure pyromellitic anhydride (PMDA) was gotton by heating pure pyromellitic acid in vacuum chamber at 260°C for 3 h. The remaining BPCA which through 2-pentanone recrystallization was isomerizated with consistent temperature at 420°C for 2 h. Appropriation pH of BPCA, initial pressure of carbon dioxide and cadmium carbonate catalyst were provided to produce crude terephthalic acid (TPA). Pure TPA was obtained by washing and drying the crude TPA precipitation.

With the use of high-speed (to 6 × 10⁵ frames per second) video recording facilities, the following three physicochemical transformation regimes were recognized on the induction heating of the single particles (4–6 mm in size) of D coal on a steel plate (at a temperature of no higher than 1000 K): thermal decomposition without ignition, smoldering, and ignition. The limiting (minimum) values of heat source temperatures necessary and sufficient for the initiation of combustion of coal particles were established.The effect of particle sizes on the integral characteristics of the test process was found. The particle-size dependence of the time of heating of a natural solid fuel particle to the intense development of an exothermic reaction was obtained. It was found that the characteristic times of the initiation of the ignition and smoldering regimes were no longer than 10 and 20 s, respectively, with variations in coal particle size.

The mechanism of the formation of ash deposits on the internal surfaces of equipment during the thermochemical conversion of wood biomass was investigated. It was shown that the transfer of the mineral matter of fuel wood through a gas phase is the prevailing mechanism. The thermodynamic calculation of the equilibrium concentrations of the main mineral matter components in the gas phase was performed with and without consideration for the organic matter of fuel. The atomic absorption analysis and thermal analysis of the mineral matter of wood was carried out.

A systematic study of the chemical and phase composition and structure of the shells of narrow fractions of nonmagnetic cenospheres separated from a concentrate of fly ash cenospheres from the combustion of pulverized SS (weakly caking coal) coal from the Ekibastuz Basin was carried out. It was found that the separated narrow fractions were characterized by a high Al₂O₃ content of 33–38 wt %. The phase composition included 57–73 wt % vitreous phase, 25–40 wt % mullite, and 1.2–2.5 wt % quartz. An increase in the average diameter, thickness, and porosity of the glass-crystalline shell of globules with the concentration of aluminum was observed. Globules of the following two types were identified in the obtained fractions: spherical globules with an annular structure and foamy globules with a network structure formed from different illite and kaolinite mineral precursors, respectively.

The results of the hydrogenation of anthracene in ethanol in the presence of different catalysts (the nanosized powders of Fe, Cu, and β-FeOOH and Ni and Fe supported on carbon microspheres) are reported. The greatest catalytic effect was observed upon the introduction of 1.5% Fe nanopowder.