Coke and Chemistry最新文献

A process is developed for the production of highly reactive water–coal fuel by oil granulation, vibrational and cavitational treatment of water–coal suspension, with the addition of a highly reactive component (methanol). The preparation of such water–coal fuel from Kuznetsk Basin coal of different ranks and with different ash content is studied experimentally. The possibility of obtaining a composite fuel using fuel oil and methyl alcohol is investigated. The method is refined and the parameters of deep coal enrichment by means of oil granulation are determined. Coal–oil granulates of ash content ≤5.5% are obtained, and the possibility of preparing highly reactive water–coal fuel on that basis by the proposed technological process is considered. The highly reactive water–coal fuel is prepared by wet crushing of coal in a vibrational mill, with treatment of the suspension obtained in a rotary–pulsational cavitation system. The structural, rheological, and thermophysical properties of the highly reactive water–coal fuel are investigated. The flash point of the fuel when methanol constitutes 51.3% of the liquid phase is 29°C; its freezing point is below –14.5°C.

Coal from the Kansk-Achinsk and South Ural basins and their extracts—humic acids, hymatomelanic acids, and bituminous resins—are studied by technical and elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and ¹³C NMR spectroscopy. The bitumen composition is investigated by chromatography and mass spectrometry. Data are presented for the phytostimulant activity of hymatomelanic acids and their mixtures with the saponifiable component of the extracted bituminous resin with respect to Aphrodite wheat seeds. Such activity is established for the samples, whether used individually or in combination. The phytoactivity index (PI) is found to be in the range 1.09–1.20.

The thermal stability of carbon sorbents modified by ammonium bromide is investigated. The sorbent is produced from D coal by alkaline activation at 800°C with 1 h holding, when the coal/KOH mass ratio is 1.0. This sorbent is microporous, with a high specific surface (1340 m²/g). The sorbent is modified by steeping with ammonium bromide solution of different concentrations (1, 2, and 4%). Such modification changes all the textural characteristics of the sorbent. The specific surface S_BET and total pore volume V_Σ decrease. Thermogravimetric analysis establishes the temperature limits on oxidative pyrolysis of the sorbent samples: the ignition temperature and complete combustion temperature. Taking account of the time parameters, the ignition and combustion indices are calculated. It is found that increase in concentration of the ammonium bromide solution is accompanied by increase in the ignition temperature T_ig of the samples and also the temperature T₁ at which mass loss begins. In addition, the ignition index D and combustion index S increase. The results show that modification of the sorbents with ammonium bromide raises the threshold of oxidative pyrolysis.

The development of coal flotation using a modifier is considered. The modifier considered is a petrochemical product: sodium μ-iso-nonylphenoxyethylene carbonate (Sinterol). Its molecules contain an anionic–cationic structure with the general formula: H₁₉C₉–C₆H₄–O(C₂H₄O)_nCOONa. In studying the influence of the modifier consumption on the effectiveness and selectivity of coal flotation, the collector employed is an oil-refining byproduct: Motoalkilat (MTA). The frothing agent is KOBS, which is the still residue from the production of butyl alcohol. The acetylene reagent DK-80 is also employed as a collector. By using DK-80 reagent and the modifier Sinterol in the flotation of coal with different mineral content, the physicochemical properties of the coal surface may be altered and the flotation process may be improved. This combination reduces the consumption of the main reagents and tends to increase the extraction of combustible mass in the concentrate and to reduce the losses of organic mass with the flotation wastes. In addition, the use of Sinterol diminishes the environmental impact of flotation.

The surface morphology and porous structure of lignite samples are studied. Irregular amorphous particles are found to predominate. According to the results of energy-dispersive X-ray (EDX) analysis, the chemical composition of the samples’ mineral components is practically the same. The lignite samples are characterized by high calcium content. The porous structure of the samples is practically identical. The specific surface is small. The pore space consists of mesopores of mean diameter 18–28 nm.

When interstitial clay, which is the waste from shale combustion, is fired at 250°C, the decomposition of organic matter results in the emission of H₂, CO, SO₃, and CO₂ from the ceramic samples. At 350–550°C, the content of oxidant (oxygen) and neutral gas (nitrogen) is markedly less. At 550–750°C, no sharp decrease in their content is observed. At 750–1000°C, the decrease is slight. At 1000°C, mainly CO is formed. At 1050°C, the fired sample contains practically no organic compounds. More complex compounds (anorthite, diopside) are formed, with increase in the mechanical strength.

In the first article of this series, the influence of the preparation and heat treatment of heavy tar on the yield, softening point, degree of coking, and density of petroleum pitch was considered [1]. In the present article, the influence of the preparation of heavy pyrolysis tar on the group composition of the produced is studied. The influence of the group components on the coking properties and softening point of the pitch is considered. By adjusting the production conditions, the group composition of the pitch may be regulated, and pitch of specified quality may be obtained.

The morphology, structure, and mineral composition of carbonized industrial samples are studied by scanning electron microscopy. According to the results, the carbonized samples include particles of different sizes, which are covered by a layer of organic mass containing oxygen. Disperse amorphous calcium carbonate is also present, as confirmed by the decrease in oxygen content at the surface of the particles after heating the sample to 800°C in an inert atmosphere. The mineral component of the carbonized sample is found to contain the elements Ca and Mg, which are typical of lignite. The microstructure established for the sample is also typical of carbonized lignite.

Humic substances—humic acid, hymatomelanic acid, humus acid, and fulvic acid—have been isolated from lignite mined in the Tisulsky deposit of Kansk-Achinsk Basin. The samples obtained are characterized by means of technical and elemental analysis. The content of functional groups is determined by potentiometric titration. For all the acids, the content of carboxyl and hydroxyl groups in the humic substances may be ranked as follows: Ar–OH > Ar–COOH > Alk–COOH.