Allerton Press

The results of studies on the preparation of carbon nanofibers from electrocracking gas (obtained by the decomposition of a diesel fraction (180–350°C) in electric discharges) on an iron oxide catalyst are presented. The effect of synthesis conditions on the yield and characteristics of the resulting nanofibers was demonstrated.

Experiments on the air gasification of coal in a circulating fluidized-bed gas generator with a stagnant layer are described. The results of the experiments are consistent with simulation data. Based on a gas generator model, optimum process parameters—temperatures in gasification and combustion chambers, chemical efficiency, and coal fraction supplied to the gasification chamber—were found.

To comparatively analyze the distribution characteristics of spontaneous combustion hazard zones in upside and downside ventilation airflow adopted mining areas, field measurements of O2 and CO concentrations were determined at the two sides of intake and return airways and the middle of the goaf in 1201 working face of DuanWang Mine; characteristic combustion temperatures and spontaneous ignition kinetic parameters of coal samples were obtained by thermogravimetric analysis; distributions of oxygen and temperature fields under different heat source intensities in upside and downside ventilation airflow adopted working faces were compared by CFD simulation. The results show that the critical positions of the inertisation zone in the goaf corresponding to the intake side, return side and middle of the working face were 200 m, 290 m and 175 m away from the working face, respectively; the moisture evaporating temperature of the coal sample was around 170°C, and the ignition point temperature was about 320°C. When the heat flux was 0 W/m2, the areas of spontaneous combustion hazard zones (oxygen volume fraction >8%) in upside and downside ventilation airflows adopted goafs were almost the same; as the heat source increased, the distribution of spontaneous combustion hazard zones in the goaf was more significantly affected by the hot wind pressure, the hazardous area in upside ventilation goaf was about 3 times of that in downside ventilation when the heat flux reached 20 W/m2. The simulation laws were consistent with the measured results. The comparative analysis concludes that downside ventilation is conducive to preventing and controlling spontaneous combustion of residual coal in this working face.

The properties of cobalt catalysts for the Fischer-Tropsch synthesis used in XTL processes (the conversion of any organic raw materials into liquid hydrocarbons) are considered. It is shown that the catalysts used for the production of synthetic petroleum are characterized by a relatively low activity in polymerization reactions, and they make it possible to obtain hydrocarbon mixtures with the concentration of solid paraffins no higher than 10%. The catalysts used for conducting the synthesis of middle oil distillates are characterized by high polymerizing activity (alpha of 0.9 or higher) and by the high yields of C5+ hydrocarbons.

The technique of Сo-catalyst preparation through the step of shungite modifying of Zazhoginsky deposit (Russia). The morphology surface, elemental composition and structural and functional characteristics of the catalyst were studied. As a result of the Fischer-Tropsch synthesis at atmospheric pressure and a temperature range of 260–380°C in the presence of Co-catalyst the optimum content of cobalt in the catalyst system to produce liquid hydrocarbons was determined.

The process of the thermal decomposition of the samples of mixed industrial and municipal wastewater sludge was investigated using gas chromatography. The composition of pyrolysis products obtained at temperatures of 200, 250, 300, 400, 500, and 600°C was determined. The groups of organic compounds detected in the pyrolysis products were analyzed. The temperatures of the onset of the release of volatile organic components and the highest heat release were determined.

The study of the coals of Long-flame–Gas brands with different methane contents showed that the methane content of coal beds is mainly related to the nanostructure of coal matter, and it does not depend on the porosity of coal. The molecules of methane penetrate directly into the coal structure, and they become absorbed by sorption sites that appear on the dangling bonds of aromatic and conjugated-chain structural fragments of coal.

The possibility of obtaining carbon sorbents from a fine fraction of medium-temperature coke for the removal of phenols from industrial water and wastewater was demonstrated. This excludes the carbonization of coal material as one of the economically costly stages. The resulting samples were tested for the ability to absorb phenol. The phenol content of water after purification with K12 and ShK sorbents decreased from 251.00 to 0.0572 and 0.737 mg/L, respectively.

The effect of the oxidized surface of brown coal on the structural and rheological properties of water-coal slurries was found. The kinetics of structure formation processes in water-coal slurries based on as-received and oxidized brown coal was studied. The effect of lignosulfonate and alkali additives on the samples of brown coal was considered.