The influence of initial raw materials derived from petroleum and coal (pitch and coke) in the anodic mass on the benzo[a]pyrene emission during carbonization is investigated. Experiments show that the rate and completeness of benzo[a]pyrene emission are affected not only by the temperature and heating rate of the anode masses but also by the characteristics of the pitch binder and coke filler.

Industrial samples of coal tar pitch are investigated by means of Raman spectroscopy. On the basis of the analysis, relationships are established for the physicochemical properties of various pitch samples. Increase in the softening temperature is associated with the growth of graphite-like crystallites on account of increase in the proportion of edge defects. An inverse correlation is found between the tangent of the inclination of the pitch’s basic spectral line and its composition (in terms of pitch grades).

The use of poorly caking SS coal as a reducing agent in electrofurnace production of ferrosilicon is considered. The characteristics of coke nits, SS coal, and wood chips are compared. SS coal offers some advantages over coke as a reducing agent: lower ash content (Ad = 4.6, as against 11.2%); lower sulfur content (Sd = 0.26, as against 0.43%); very high electrical resistivity (ρ > 3.3 × 106, as against 3.7 Ω cm); and elevated reactivity with CO2 at 1000°C (\({{K}_{{{\text{C}}{{{\text{O}}}_{2}}}}}\) = 1.92, as against 0.49 cm3/g s). The ash from SS coal has a low content of the oxides Al2O3, TiO2,and P2O5, which are harmful for ferrosilicon: the total (per 100 kg of carbon) is 2.2 times less than for coke. The gas obtained by pyrolysis of SS coal (at 900°C) has a high content of reducing components: CO + H2 = 210.8 m3/t, as against 11.2 m3/t for coke. At 1500°C, the content of CO + H2 in the gas is 80.8%. In heating SS coal to the temperature at the top of the electrofurnace (700–1000°C), its physicochemical properties change. However, it retains its advantages over coke: the carbon content Cfix increases to 91–92%; the carbon in the organic mass Cdaf is 96–98%; the porosity is 38–49%; and the structural strength is 80%. Industrial experiments (for 96–229 days) on the use of SS coal in a mixture with coke and wood chips shows that this is an effective reducing agent in the production of FS75 ferrosilicon. It ensures stable furnace operation, with 1.9–3.2% increase in productivity and 2.8–5.2% decrease in power consumption. In terms of carbon content, 43–47% of the coke may be replaced by SS coal.

By scanning electron microscopy, X-ray phase analysis, and X-ray structural analysis, the morphology and structure of the mesophase is studied in the series: coal tar → coal tar pitch → α fraction → coke residue obtained on heating the [alpha] fraction at 1200°C. The X-ray structural parameters are determined: the longitudinal and transverse dimensions of the stacks of polyarene layers (La and Lc); the distance between layers (d002); and the number of layers in each stack (N). In carbonization, the two-dimensional carbon mesophase structures are converted to three-dimensional stacks. The mesophase consists of a turbostratic carbon structure and graphite-like phases. The transverse dimension of the stack formed on structuring is Lc = 1–2 nm; its longitudinal dimension is La = 2–6 nm. The mean distance between the layers in the samples is d002 = 0.346–0.355 nm. The pitch has an isotropic structure since the mesophase consists of spheroids.

Existing methods of determining the specific surface of special coke (rexil) produced by thermal oxidative coking of long-flame Shubarkol coal are reviewed. The specific surface of the specific surface is determined by those methods. The relation between the heating rate of the initial coal and the specific surface of the special coke is established experimentally. On that basis, a method of determining the specific surface of fine-pore special coke obtained by fast thermal oxidative coking is selected.

The reactivity CRI and mechanical strength CSR of coke are investigated as a function of the parameters of the oriented molecular domains within the coke (height Lc and width La of the packet of carbon layers). Industrial coke samples from MMK are investigated: they are tested to determine the reactivity CRI and mechanical strength CSR of the coke after reaction (State Standard GOST R 54250). A linear relation between M10 and M25 is confirmed in describing the results of Micum drum tests in an alternative parallel–serial configuration. Close correlations are found between the domain height Lc before gasification and CRI and between Lc after gasification and CSR. No such relations could be established for La. It is found that, after gasification, the content of oxides such as Fe2O3, CaO, MgO, K2O, MnO, SrO, and SO3 in the ash decreases. This probably indicates gasification over the whole of the coke piece and the entrainment of loose oxides by the carbon dioxide and carbon monoxide. Analysis of coke residues after drum tests indicates that coke pieces of different size exhibit different failure dynamics: the best CSR values are obtained for large coal pieces. Ideas are formulated regarding the influence of oriented molecular domains on the strength and reactivity of coke.

The recycling of solid industrial waste—coal sludge and petroleum coke breeze—is considered. The advantages and disadvantages of the main processing methods are evaluated. The most promising technique is shaping with binder. The strength of composites consisting of coal dust and coke breeze is investigated. Heavy tar and petroleum pitch are used as sintering additives in the composites. The sintering properties (according to the Roga method) are investigated as a function of the content of tar or petroleum pitch in the mixture (over the range from 1 : 0 to 0 : 1). The results show that the composites’ strength and resistance to abrasion are improved, up to some limit. In the presence of 20 wt % heavy tar, the Roga index RI = 62; for composites containing 30 wt % pitch with coke breeze or with coal dust. When the tar content is 10–35 wt % or the petroleum pitch content is 5–55 wt %, the Roga index meets the technical requirements (RI > 50).

The design of the mechanism for opening and closing the chute doors of a rail car in a coke-quenching system is discussed. Modernization of the hydraulic system ensures uniform discharge of the quenched coke on the coke ramp and increases the working life of the main pump. Assessment of the performance of such hydraulic systems and pumping equipment is considered. New hydraulic drive systems for the pumping equipment are proposed, as well as individual mechanisms of the device.

AbstractIn order to investigate the carbon solution loss reaction in CDQ, this paper used thermo-gravimetric device to simulate the environment of a dry quenching furnace to investigate the effect of CO2, H2O (g) and CO2 + H2O (g) gas mixtures at low concentrations (<20%) on carbon solution loss of coke. The results showed that the reactivity of H2O (g) with coke was higher than that of CO2 at the same concentration, and that the reactivity of coke in the mixed atmosphere is lower than the sum of the independent reactivity of coke with CO2 and H2O (g) but higher than the reactivity of the corresponding single gas. The activation energy of the coke gasification reaction with H2O(g) was lower through calculating the kinetic parameters using the Coats-Redfern method, and the coke strength after reaction of nonisothermal (CSRnon) was lower than with CO2. The content of isotropic structure of coke decreased significantly after reaction with the increase of reaction CO2 and H2O (g) concentration, while the content of anisotropic structure increased. The surface of the coke was relatively smooth after reaction with CO2 by SEM, while that had increased in roughness and pore size after reaction with H2O (g), and it was severely eroded like a honeycomb after reaction with CO2 + H2O (g), which indicated that the coke pores were opened and expanded action under the erosion of CO2 + H2O (g), resulting in the thinning and even breaking of the pore walls and the formation of gas reaction channels.

AbstractCoke structure can be divided into cracks, pores and coke matrix. In this work, a coke cross section model was established. Moreover, a rectangle and two ellipses with different sizes were also constructed to represent cracks and pores, respectively. The effects of mechanical force and thermal stress on cracks and pores were studied. The results showed that the coke matrix adjacent to the pores was relatively stable in comparison to the coke matrix adjacent to the crack. In addition, the continuous production and extension of cracks would result in the occurrence of a coke “perforation” phenomenon, causing the coke structure to be damaged and coke size and strength to be reduced due to mechanical force. Compared with the strong effects of mechanical force on coke, thermal stress will not cause the fracture phenomenon, but only change the shape. Moreover, it was also found that mechanical force destroys coke rapidly and greatly comparing thermal stress. This work revealed the evolution of coke under mechanical force and thermal stress and provides theoretical support for coal-blending coking.

An acoustic method is proposed to intensify heat and mass transfer and decrease dust extraction in a rotating single-flow drum for drying D coal. An acoustic field is formed in the working space by means of two Hartmann whistles at the end surfaces of the discharge chamber, Experimental data regarding the change in the material and thermal balance indicates that the use of acoustic energy in a drying drum increases its productivity in terms of dry coal (by 4.76%) and also decreases the exhaust gases (by 8.98%) and the dust emissions (by 5.75%), while increasing the moisture removal from the coal (by 12.5%). With increased consumption of the fuel’s heat by 14.4%, the loss of heat with the exhaust gases is decreased by 12.61% and the loss with the dust by 9.41%. The total heat losses to the environment are decreased by 6.25%. With decrease in productivity of the drying drum in terms of wet coal by a factor of 1.75–1.98 and the use of acoustic energy, the yield of dry coal is increased by 12.06%, the proportion of fuel oil by 108% and the dust yield by 71.89%, with decrease in the participation of volatiles in heat treatment by 86.11% and decrease in the participation of recirculated material by 17.48%. The quantity of gas extracted is decreased by 35.5%, and moisture removal is decreased by 11.14%. The thermal efficiency of the system is hardly changed (by 0.987%). The use of acoustic energy is an inexpensive and efficient means of improving the thermal operation of drying drums.

Reactions in heterogeneous mixtures between components in flotation are analyzed. Two models are employed: one describes reactions at the surface of the coal’s organic mass (the on-water model); the other describes reactions in the water itself (the in-water model). The influence of the water’s network of hydrogen bonds is studied. Since that network is interrupted at the water’s surface, chemical reactions occur by different mechanisms at the surface than within the volume of the water. Hydrogen bonds are formed in two parallel processes: uniform processes (in-water processes) for hydrocarbon radicals of the reagent molecules and superfine coal particles; and heterogeneous reactions (on-water processes) for large coal particles. Quantum chemical calculations indicate how different hydrogen bonds are formed by on-water models, when the surface of the coal’s organic mass makes a pronounced contribution to the energy of the hydrogen bonds, ensuring flotation. The combination of the energy of the hydrogen bonds and the binding energy of the chemisorptional collection reagents considerably intensifies flotation.

Aspects of the separate sorting of large and small coke are considered on the basis of laboratory and industrial experiments. Changes in size, mechanical strength, and physicochemical properties of the coke are noted with variation in the sorting conditions, the coke preparation, and the equipment employed. New grades of coke are tested in the production of iron and ferroalloys.

A method is proposed for producing coke from distilled coal tar fractions. The influence of heat treatment of the tar fractions on the coke yield is investigated. The physicochemical characteristics of the coke produced from the tar fraction boiling above 280°C are investigated.

The rank structure of the available coking coal from distributed and unallocated underground sources shows that it remains unbalanced: the coke group (K, KO, and OS) and the lean additive (KS) are underrepresented. Only a third of the proven reserves of coking coal permit the production of optimal coking batch. Analysis of the rank structure of the coking coal produced for domestic use shows that the extraction of the coking base (K and KO) is greater than is necessary for the production of optimal batch, leading to premature exhaustion of these reserves.

By chromatography and mass spectroscopy and also by IR spectroscopy, the chemical composition of industrial heavy fuel-oil fractions from the semicoking of kukersite shale in a Kiviter gas generator and in a Petroter system based on hot ash is investigated. The content of different chemical groups in the samples is compared. The content of hydrocarbons is higher by a factor of about 1.5 in the fuel oil from the Kiviter system than in that from the Peteroter-1 system, while the content of oxygen compounds is lower by a factor of 1.12. The content of nitrogen compounds is approximately the same, while the content of sulfur compounds is higher for the Petroter-1 system. The heavy fuel-oil fractions are used in commercial furnace oils with up to 0.8% sulfur content: VKG C, VKG-D, VKGD-1, and VKGD-2. The resulting fuel oils are compatible with marine fuels.

Most processes in coal extraction (hydraulic fracturing, plugging of cracks, irrigation of the exposed mass with deactivating liquid) and initial processing (enrichment) depend on the wetting properties of the coal’s external surface. Atmospheric oxidation changes the composition of the surface functional groups that determine the hydrating properties of coal. In the present work, the influence of initial oxidation of the coal on the composition of the functional oxygen and hydrocarbon groups is assessed. The wettability of the surface is characterized not only by determining the limiting wetting angle but by liquid filtration through coal powder. The differences in the wetting of the surface by water and the filtration properties on oxidation of the coal surface are established. It is found that, as oxidation proceeds, the hydration of the surface and its filtration properties increase.

The sources of the major pollutants in quarry wastewater are investigated for Kuznetsk Basin coal mines. Various methods of removing those pollutants are analyzed, identifying their advantages and disadvantages. A search of foreign patents permits recommendations regarding promising decontamination methods.

The utilization of waste heat in the coke oven riser is an important means of energy reuse in the coking industry, it has a good development prospect in the field of waste heat recovery in China. The uniformity of flow distribution in water distribution system for waste heat utilization system (WHU) with the jacketed coke oven riser (JR) is an important factor affecting the normal and steady operation of WHU with JR. Too much water flow in the JR will lead to excessive heat transfer, tar condensation, black smoke phenomenon, and pollution of the environment. Too little water flow in the JR will cause serious damage to the JR and even threaten the safe operation of the coke oven. Therefore, the uneven water flow in the water distribution for the WHU with JR seriously restricts the development of this technology. So in this work, a 3D CFD model was established to study how to improve the flow distribution uniformity of water distribution for the WHU with JR. The key factors such as inlet velocity and pressure, the diameter of the main inlet pipe, outlet pipe and branch pipes, the number of JRs in a subgroup and different inlet and outlet methods were studied. The results showed that the larger the inlet velocity, the larger the diameter of the main inlet and outlet pipe, the smaller the diameter of the branch pipe, and the more number of the JRs in a subgroup, the better the uniformity of flow distribution. The value of the inlet pressure had no obvious effect on it. Among different inlet and outlet methods, Mid2-type is the most uniform method in flow distribution. The research results can provide theoretical guidance for future engineering practice and promote the development of WHU technology with JR.

Coking coal amounts to about half of Russia’s coal reserves. An algorithm is proposed for calculating the methane release from coal. It is suitable for all grades of coking coal in underground mining. Estimates of the stress in the rock and the steps in roof collapse permit determination of the arching of the roof rock and the unloading zone of the coking coal bed at the face. The methane distribution is determined in terms of the states in which it exists at the face, including the formation of free methane.