Properties of Ulug Khem coal. 2. Quality of coke from batch containing Mezhegei coal

On the basis of the laboratory coking of production batches at OAO EVRAZ NTMK, including those containing coal from the Mezhegei deposit, a new coking index is proposed. This index is incorporated in a mathematical model for predicting coke quality (CSR and CRI).     

Properties of Ulug Khem Coal. 1. Types of vitrinite and its associations with microcomponents and minerals

A review of research on Ulug Khem coal between 1951 and 2013 shows that its properties are largely determined by the plant material from which it is formed. This results in different types of vitrinite in Ulug Khem coal, with differences in clinkering properties, vitrinite reflectance, and yield of volatiles. Detailed petrographic analysis of coal from the Ulug bed in the Mezhegei deposit shows numerous associations of collinite with telinite and of telinite with bitumenite and also numerous associations of vitrinite with minerals. Thanks to the different properties of different types of vitrinite in Ulug Khem coal, the different associations of vitrinite with minerals, and the high ash basicity, coke produced from batch containing Ulug Khem coal will be characterized by low CSR and high CRI. That finding will be discussed in part 2.     

Elegest coal in coking batch at OAO EVRAZ ZSMK

The coking of batch with different proportions of Elegest coal from the Ulug-Khemsk Basin is investigated in laboratory and production conditions. The mechanical strength of the coke is improved when such coal is used in the batch. At the same time, CSR falls, while CRI rises.     

Adding coke dust to coal batch

The granulometric composition of coke dust from the dry-slaking machine is determined. The influence of additions of 3−7% coke dust on the quality of industrial coking batch and the coke obtained by box coking is estimated. Adding 1% coke dust to coking batch does not markedly change the coke quality. Industrial equipment for the supply of dry-slaking dust to the batch is described.     

Uniformity of coal batch and coke quality

Improving the mixing of batch components in the charge significantly improves their wear resistance but does not affect the crushability, on account of the different disintegration processes of the coke pieces.     

Group chemical composition of coal batch and reactivity of coke 1. Determining coke reactivity

With a view to finding correlations between coke reactivity and the coal batch employed, methods of determining coke reactivity are considered—in particular, the standard and pulsed methods. The kinetic equation fundamental to all methods of assessing the coke reactivity from the gasification rate constant is presented. The possibility of combining data obtained by different methods of estimating the coke reactivity is established.     

Group chemical composition of coal batch and reactivity of coke. 3. Phase composition of the primary products of coal pyrolysis

The action of the group chemical composition of coal’s organic mass on its phase composition in the plastic state and hence on the coke quality is quantitatively described and experimentally verified.     

Group chemical composition of coal batch and reactivity of coke. Part 2

The dependence of CRI and CSR on the group chemical composition of coal and coal batch is investigated. This dependence is associated with change in the coal properties in the plastic state.     

Influence of the moisture content of coal batch on coke quality

The strength of coke is greatly affected by the elevated and variable moisture content of the coal batch. The moisture content of the batch supplied to coal-preparation shops at coke plants must be no more than 6–7%. Otherwise, the plant must take measures to dry the coal.     

Influence of the coking properties of coal batch on coke properties

At OAO Zapadno-Sibirskii Metallurgicheskii Kombinat (ZSMK), research is undertaken to improve the optimization of coking batch. The basic approach, proposed by specialists from OAO Nizhne-tagil’skii Metallurgicheskii Kombinat, employs the coefficient K _opt, which characterizes the deviation of the batch from its optimal composition. The coking properties of the OAO ZSMK coal batch over the last few years are analyzed. After laboratory and industrial coking of batch with different K _opt, the strength and reactivity of the resulting coke is investigated. Evaluation of coke-grade coal in terms of its rank according to State Standard GOST 25543-88 proves inadequate, since coal of the same rank may differ markedly in coking properties. A method is established for assessing the optimality of the coal batch at OAO ZSMK.     

Quality of coal tar in coke production

The reasons for the differences in coal-tar quality in byproduct-capture shops 1 and 2 at PAOAvdeevskii Koksokhimicheskii Zavod (AKKhZ) are explored. The influence of the below-roof temperature and the factors on which it depends is established.     

Influence of thermally prepared G coal in compacted batch on coke strength

The strength of coke produced from compacted batch containing G coal that has been thermally prepared in an electromagnetic field is considered. Mathematical models are obtained for estimating the coke quality on the basis of composition-property plots.     

Influence of microwave-treated G coal in the batch on the coke quality

The factors that affect the heating of poorly clinkering G coal in microwave treatment are identified. Mathematical models describing their influence on the thermoplastic characteristics of the treated coal and the resulting coke quality are developed. Recommendations are made regarding the composition of batch containing microwave-treated coal.     

Kinetics of coke formation from coal solutions

The reaction kinetics for the formation of mesophase from coal solutions has been studied under conditions similar to those experienced in a delayed coker preheater coil, i.e. at temperatures from 475 to 525 °C approached at high heating rates. The degree of polymerization of the heat-treated materials has been assessed by their solubility in two solvents, cyclohexane and quinoline. An approximation has been made in order to make a kinetic analysis for the formation of insolubles in a non-isothermal system. It has been found that the polymerization of the dissolved coal component, as evidenced by the formation of quinoline insolubles during the heat-treatment of concentrated coal solutions, is essentially a second-order reaction with an apparent activation energy of ≈190 kJ mol^?1. The formation of cyclohexane insolubles from the diluent oil is a slower reaction showing first-order kinetics.     

Influence of the high content of Zh coal in coking batch on the coke quality

Industrial tests show that the enrichment of coal batch containing more than 70% Zh coal must be increased in order to boost coke strength. However, it makes more sense to replace some of the Zh coal in the batch with an optimal quantity of G coal, and to reduce the degree of crushing, so as to ensure coke quality consistent with blast-furnace requirements (minimum strength M ₂₅ = 90%, M ₁₀ = 6%).     

Influence of petroleum coking additive on the quality of coal batch,coke, and tar

Given the shortage of coal with good coking properties, a petroleum coking additive is introduced in coal batch so as to expand the range of plasticity. This additive improves coke quality in every respect, except the total sulfur content. Measures to reduce the additive’s negative impact on the coal pitch are considered.     

Composition, structure, and properties of coal from the 2.2 Ulug bed of the Elegestsk deposit in Ulug-Khemsk coal basin

Coal from the 2.2 Ulug bed of the Elegestsk deposit in Ulug-Khemsk coal basin is investigated in terms of international quality certification. According to State Standard GOST 25543-88, the coal is of rank Zh and technological group 2Zh. The coal’s code according to the international system and State Standard GOST 30313-95 is 08 0 01 8 38 05 04 36. Attention is paid to the composition and structure of the coal, which are associated with elevated clinkering properties at high vitrinite reflectance, as well as maximum yield and fluidity of thermostable liquid products in the coal’s plastic mass. These features indicate that the coal’s organic mass contains considerable quantities of thermally unstable hydroaromatic and aliphatic structures. On account of the low oxygen content in the organic mass of coal from the Ulug bed, with high quantities of carbon and hydrogen, much of the hydrogen formed on thermal destruction reacts with the radicals formed, which prevents their polycondensation, and considerable quantities of relatively low-molecular liquid products of the plastic mass are produced. The mineral component is characterized by low content of silicon and aluminum oxides (51.65%) and relatively high content of iron oxide (15.96%) and calcium oxide (15.07%). Accordingly, the base/acid ratio I _b and basicity index B _b are high: 0.692 and 6.29, respectively. The Donets Basin has no counterparts of this coal. Coal from the 2.2 Ulug bed of the Elegestsk deposit in Ulug-Khemsk coal basin may be regarded as a valuable component of coal batch.     

Ceramic coatings from batch containing nonferrous slags

Translated from Steklo i Keramika, No. 7, pp. 2–4, July, 1990.