Coke and Chemistry最新文献

Rhododendron ponticum L. is a woody biomass commonly found in the Western Black Sea region of Turkey. This study aims to investigate the feasibility of Rhododendron ponticum L. in the energy field. For this purpose, Rhododendron ponticum L. was carbonized in a semi pilot Jenkner carbonization system at a heating rate of 3°C/min at temperatures of 350 and 550°C for 1 h. Structural characterization of the obtained liquid (biotar) and solid (biochar) products was investigated. The chemical characterization of biotar was carried out with elemental and proximate analyses, FTIR and ¹H NMR spectroscopies. The structural characterization of biochar was also investigated by elemental analysis, proximate analysis, FTIR spectroscopy and SEM images.

The change in composition and characteristics of anthracene oil from coal tar on reacting with hydrogen acceptors (α-methylstyrene and nitrobenzene) at 360°C is studied. Besides the formation of cumene and aniline by the transfer of hydrogen from the anthracene oil, α-methylstyrene and nitrobenzene react with components in the anthracene oil to form products that cannot be determined by chromatography. In addition, polymerization of the components in the anthracene oil is observed. The anthracene oil is analyzed after reaction with α-methylstyrene and nitrobenzene by means of gas–liquid chromatography, elemental analysis, thermogravimetric analysis, gel permeation chromatography, NMR ¹H spectroscopy, IR spectroscopy, and UV fluorescent spectroscopy.

Currently, Raman spectroscopy is the primary method of investigating carbon materials. In the present work, coke samples produced from the same batch but with different final temperatures are studied. On the basis of correlations between the spectral characteristics and the hot properties of the coke, the coking temperature corresponding to the best coke quality is determined. The potential of Raman spectroscopy for express tests of coke is demonstrated.

An additive model is used to calculate the main plastometric index: the plastic layer thickness Y for coal batch with 3–5 components. Calculated and experimental values of Y are compared. In the practical range of batch compositions, the additive approach permits determination of Y at a 95% confidence level. The results are verified for the batch components in the coke plant at Magnitorsk Iron and Steel Works (MMK).

The use of activated charcoal in electrodes for supercapacitors seems very promising. When activated charcoal is treated with aqueous hydrogen peroxide solution, oxygen-bearing functional groups are formed—primarily carbonyl groups. (This process is known as functionalization.) That results in approximately 40% increase in the electrical capacitance. If filler—2 wt % gold nanoparticles—is introduced in the resulting material, its pore structure is not blocked. By this means, the electrical capacitance may be increased by a further ~10%. The electrical capacitance of this nanostructured electrode material proves very stable (~86%) in repeated cycling of the potential (up to 500 cycles).

This paper kinetically studied the metallurgical coke nonisothermal gasification by thermogravimetry. The random pore model (RPM) was made use of to describe gasification kinetic behavior. The RPM parameters were optimized using two methods, viz. the method using genetic algorithm alone and the method combining genetic algorithm and least squares. By comparison with the former method, the latter yielded more accurate parameters. Theoretical curves obtained from the method combining genetic algorithm and least squares matched experimental ones well.

This research explores the geopolymerization mechanism in alkali-activated fly ash under high-pressure conditions to better understand the development of binder gels. Fly ash was activated using either sodium hydroxide alone or a mixture of sodium silicate solution and sodium hydroxide, followed by curing at 120°C under 0.22 MPa pressure for the initial 24 h. The impact of pressure on the formation and transformation of the binder gel was examined using advanced analytical methods, such as synchrotron X-ray diffraction and solid-state Si and Al MAS NMR spectroscopy. The results reveal that the reactivity of raw fly ash and the formation of zeolite phases were notably increased in samples activated with sodium hydroxide alone. In contrast, the effects of elevated pressure were less significant in samples activated with the sodium silicate solution. These findings are crucial for optimizing geopolymer binder design, as the extent of crystallization plays a key role in determining the long-term performance and durability of geopolymer materials.

The freezing of coal in railroad cars hinders coal discharge and interferes with efficient power station operation. In particular, Urtuyskoye coal is characterized by high moisture content and hence is very susceptible to freezing. This problem may be addressed by modernizing the discharge system and preliminary treatment of the rail cars. Various methods of unloading frozen coal are considered, such as heating, mechanical action, and the use of antifreeze. The proposed method includes thawing of the cargo by means of infrared heaters to prevent obstructions in the bunkers of the boiler shop and treatment of the car’s interior surfaces with Niogrin oil-based dust-binding agent. Calculations show that introducing these measures reduce the working moisture content of the coal to 22% and the ash content to 14%, with 30% increase in the calorific value. That lowers the annual fuel consumption by 23%, with considerable economic benefit.

Coal flotation when using copolymers of vinylpyridine and alkyl sulfoxides as modifiers is investigated. When the modifiers are added to coal fines at a rate of 0.5–1.0 g/t, the flotation parameters are improved: more combustible coal mass is extracted with the concentrate; and less of the coal’s organic mass is lost with the flotation waste. The effectiveness of the modifier is determined by the quantity of sulfo groups and vinylpyridine groups in the macromolecule and also by its molecular mass. The flotation is best when using 50B modifier with molecular mass 17 500 and an increased sulfo group content in the macromolecule. The modifier is more effective when it is introduced in the flotation chamber before the collector. The flotation is improved because modifier molecules are adsorbed at the energetically active sections of the coal surface. Specifically, polar groups of the copolymer are attached by hydrogen bonds, with the hydrocarbon groups oriented into the aqueous phase. That ensures increase in hydrophobic properties of the coal before the collector is added. As a result, lower consumption of the collector is possible.