Coke and Chemistry

Published by Springer Verlag
Online ISSN: 1934-8398
Print ISSN: 1068-364X
Publications
Coke battery 10A with rammed batch is under construction at OAO Alchevskkoks. The design documentation developed by Giprokoks includes measures for reducing dust emissions to the atmosphere. Aspiration systems with dry dust trapping are employed in the new components of coke battery 10A and in the existing coke-sorting equipment. Two-stage purification of dusty air in cyclones and bag filters is employed for the coke-sorting equipment. This system considerably reduces coke-dust emissions to the atmosphere.
 
Factors affecting plastometric measurements for coal are considered. The need to revise State Standard GOST 1186-87 is discussed.
 
The distribution and quality of Russian coal and coke resources are compared for periods before (the first nine months of 2008) and during (from the fourth quarter of 2008 to the second quarter of 2009) the economic crisis. Attention then turns to the definition and determination of the technological value of coal. Analysis of coke strength suggests that, in current conditions (with no crisis), the production of high-quality (high-strength) coke is not economically justified
 
The global crisis in iron and steel production is analyzed, along with its influence on coke production. Current quality requirements on blast-furnace coke are reviewed. The prospects for the coke and coking-coal markets beyond the crisis are considered.
 
The basic approaches employed in the construction of coke battery 11A at OAO Magnitogorskii Metallurgicheskii Kombinat are outlined. This battery includes 51.0-m3 furnaces and a dust-free coke-supply system designed by Giprokoks with lateral gas supply; it is heated exclusively by low-calorific mixed gas consisting of blast-furnace gas with added coke-oven gas. The 82 furnaces in the coke battery are divided into two blocks of 41. The gross coke output of the battery (6% moisture content) is 1140000 t/yr.
 
Propylene carbonate is a cyclic alkyl carbonate (1,3-dioxolan-2-one, 4-methyl), soluble in alcohol, ether, acetone, aromatic hydrocarbons, and acetic acid and insoluble in aliphatic hydrocarbons and CS2.
 
Research on extraction and absorption by ethylene carbonate in chemical technology is reviewed.
 
Coke consumption at blast furnaces is steadily rising as hot-metal production expands. Meeting the hot-metal demand simply by improving the quality of the iron ore and coke is no longer possible. The remaining options are to construct new coke batteries, to reconstruct existing batteries, and to improve the operational stability of coke batteries. High construction costs limit the applicability of the first two approaches. Accordingly, a high priority is to improve operational stability by reducing incidents and accidents and thus reducing furnace downtime.
 
An efficient production technology for unroasted briquets from lignite semicoke has been developed; the lignite semicoke is derived from Kansko-Achinsk coal. The briquetting conditions are described. In terms of strength and physicochemical properties, the semicoke briquets are suitable for use as residential heating fuel, as fuel for metallurgical shaft furnaces, and also as the reducing agent in ferroalloy production.
 
The ozonization products of regular and oxidized lignite, semicoke, and humic acids consist of a mixture of aliphatic monocarboxylic and dicarboxylic acids and aromatic polycarboxylic acids of the benzene, naphthalene, and phenanthrene series.
 
Introducing additives in BDUS 70/100 petroleum bitumen results in a high-quality binder for the preparation of floated asphalt with improved performance. Effective additives include amide waxes, natural waxes, high-molecular paraffins obtained from CO-hydrogen mixtures by the Fischer-Tropsch method, and also mixtures of high-molecular paraffins and polyethylene waxes.
 
The technologies adopted in the construction of coke battery 3 at OAO Koks are described.
 
A key problem facing highly developed nations is water management: water purification and the use and reproduction of water sources. An effective means of removing oil and oil-coated suspended particulates from coke-industry wastewater (when simpler methods, such as sedimentation and filtration, are ineffective) is flotation. Wastewater purification by flotation largely depends on the aeration; this may be an separate consideration or the decisive factor in selecting a preliminary-purification method.
 
220 We know that, in wet gas, ammonia may be in an associated state of type N · (NH 3 ) m · (H 2 O) n . Raising the temperature leads to rupture of the hydrogen bonds H 3 N…HOH and H 2 O…HNH 2 , and the ammonia is activated [1‐3]. On cooling this vapor‐gas phase, the hydrogen bonds are restored. In the presence of acidic components that give up a proton considerably more easily than water will, the reaction proceeds primarily with those components of the gas mixture. The ions that form combine with counterions and water molecules in complexes that aggregate together to form new-phase nuclei under the action of the intermolecular forces. With excess interphase surface energy, the nuclei enlarge, and heavy particles with a large specific surface appear. These general concepts are confirmed experimentally in NH 3 ‐H 2 S‐CO 2 ‐H 2 O systems. In a laboratory setup, the vapor‐gas mixtures NH 3 − CO 2 ‐H 2 O‐argon and NH 3 ‐H 2 S‐H 2 O‐argon are cooled. Light scattering by particles of the cooled vapor‐gas mixture is measured on a LMF-69 H4 nephelometer; the gas is filtered through an extractor filled with glass-fiber wadding, and the aerosol is deposited; the gas mixture ahead of and beyond the filter is analyzed on a LKhM-8MD chromatograph; the ionic‐ molecular structure of the aerosol is investigated by IR spectroscopy on a Specord-JR-75 instrument. The dispersion of the aerosol is estimated by deposition on a glass plate coated with a layer of immersional liquid; the particle size is then determined on a microscope.
 
The characteristics of special coke made from Shubarkol coal with different yields of volatiles are presented. By increasing the yield of volatiles in the special coke from the TOO Sary-Arka Spetskoks plant to optimal values (7–8%), the mechanical strength and physicochemical properties may be improved. On the basis of experience at Kemerovo coke plant, the use of a Nippon Steel drum is proposed for determining the cold mechanical strength CBS of the special coke.
 
Presentations at the International Conference on Ferroalloy Production relating to new carbon reducing agents as an alternative to coke are briefly summarized. Such reducing agents include lightweight reducing agents (peat, lignin, wood chips), coal D and the corresponding semicoke, lean coal, oil coke, low-ash coal, and Karelian shungite. The results of their industrial use are described.
 
We know that the flocculants disintegrate readily on storage [1]. Accordingly, we may expect that the aggregates obtained by their use will also disintegrate. Moreover, coal concentrates subjected to selective flocculation before coking also undergo briquetting, pressing, drying, and other processes. In studies, generally, the basic flocculation mechanism and kinetics are considered [2‐6]; no attention is paid to the kinetics of polymer destruction in the crosslinks of the aggregates. However, an understanding of the kinetics of flocculant destruction would offer an important means of managing the storage of aggregates before use in coke production [7‐10]. According to classical kinetic concepts, floccule destruction occurs in two stages [2, 3]: disintegration of the aggregates formed; and stabilization of the suspension. Note that the kinetic process of destruction is not instantaneous; we must expect a latent period in which molecular interactions occur before floccule destruction. In recent years, selective flocculants for the intensification of gravitational and flotational enrichment and for the classification of coal suspensions have been developed. In the present work, destruction will be considered for aggregates formed after selective flocculation of suspensions using BS-ZOF flocculant, which is produced in Russia and used in Ukraine.
 
Laboratory data on the aggregation of small semicoke pieces from Kansko-Achinsk lignite are presented. In the proposed method, Laboratory data on the aggregation of small semicoke pieces from Kansko-Achinsk lignite are presented. In the proposed method, the semicoke is mixed with coking coal at the output from the semicoking reactor and is then pressed and cooled. It is assumed the semicoke is mixed with coking coal at the output from the semicoking reactor and is then pressed and cooled. It is assumed that the same principle may be used to obtain composites from other small-grain materials. that the same principle may be used to obtain composites from other small-grain materials.
 
Coke transportation after wet slaking is accompanied by the release of dust in the production building and in the surrounding atmosphere. Wet methods are traditionally used to purify very humid air. Giprokoks has developed designs for highly efficient dry dust-removal methods in such conditions.
 
An integrated environmental, health, and safety management system (EHS MS) has been developed at OAO Alchevskkoks. This system incorporates two spheres of plant activity: labor safety and environmental protection. The development of EHS documentation was completed in May 2009. The system is being prepared for an audit, to permit international certification.
 
OAO Alchevskkoks, Ukraine’s second largest coke producer, is introducing many new technologies to overcome existing problems.
 
Chromatogram of the polyaromatic hydrocarbons in coal pitch.
System for removing polyaromatic hydrocarbons on carbonization: (1) thermogravitometer furnace; (2) crucible with pitch; (3) gassexhaust pipe; (4) glass trap; (5) vessel with liquid nitrogen.
Total quantity and toxicity of polyaromatic hydrocarbons
Coal pitch contains alkyl-substituted naphthalenes, as well as other aromatic compounds. To elucidate the possible transformations of the alkylation products of naphthalene, these products are treated in the presence of catalysts, and the basic compounds formed are analyzed on the basis of IR, NMR 1H, and chromatographic mass-spectrometric data.
 
The composition and physicochemical properties of Gorlovsk Basin anthracite are studied, with a view to expanding its metallurgical use. In industrial tests, anthracite is employed in smelting hot metal in cupola furnaces, in the production of carbonized products and briquets, in ferroalloy production, in sintering iron ore, and in batch for foundry coke.
 
In plant monitoring of coal quality, attention focuses primarily on the sintering properties, determined plastometrically in accordance with State Standard GOST 1186‐87 (Coal: Method of Determining Plastic Characteristics) [1]. At many Ukrainian coke plants, the plastometric characteristics of coal and coal mixtures have been determined by means of Sapozhnikov‐Bazilevich manual plastometric equipment, produced by the automation shop (now OOO Etalon) at Khar’kov Experimental Coke Plant (KECP), under the technological and methodological supervision of the Coal-Chemistry Institute (CCI). However, with the privatization of KECP, the production of plastometric equipment stopped. Today, the plastometric equipment at most coke plants is practically worn out and requires replacement. In recent years, the AP1-M automated plastometric unit was developed at NVP Zaporizhchormetavtomatika Production Facility; automation eliminates the subjective factor associated with the intervention of the laboratory staff in the experiment [2, 3]. The apparatus complies with current requirements on laboratory test equipment. It has been put into operation in the laboratories of many coke plants—in particular, the Zaporozhye, Krivoi Rog, Avdeevka, Yasinovka, Makeevka, Alchevsk, and Mariupol plants—and also in the coal department at CCI. Accordingly, it is necessary to develop consistent methodological instructions for tests of coal and coal batch and to undertake technological certification of the equipment. The results of these endeavors are summarized in the present work. The investigation consists of several stages. In the first stage, the possibility of using the AP1-M unit to determine the plastometric characteristics of Donetsk Basin sintering coals (grades G, Zh, and K) is evaluated. The consistency and reproducibility of the results obtained on the automatic AP1-M unit and on the manual Sapozhnikov equipment are evaluated. The results are presented in Table 1. Six samples of coal of the given grades are considered. Within each grade, † Deceased. coal of different sintering properties is studied. For each coal, four determinations are undertaken. The consistency and reproducibility of the results are estimated by comparing the shrinkage, the plastic-layer thickness, the temperature corresponding to the maximum plastic layer, and the character of the plastometric curve. Analysis of Table 1 shows that the AP1-M unit ensures satisfactory reproducibility of all the results. The plastic-layer thickness, which is the basic characteristic in the given method, is practically the same in tests on the AP1-M unit and the Sapozhnikov apparatus. The difference is no more than 1 mm, which indicates that the AP1-M unit may be used for the investigation of such coal. In the second stage, the possibility of using the AP1-M unit to determine the plastometric characteristics of poorly sintering Donetsk Basin coal (grades DG and OS) is evaluated. Special operating conditions of the automated plastometer have been developed for such coal. According to the data in Table 2, the AP1-M unit ensures the required consistency and reproducibility of the results.
 
The coke industry is one of the main sources of polycyclic aromatic hydrocarbons in the environment [1]. Benz[ a ]pyrene is the best known polycyclic aromatic hydrocarbon; it is a powerful carcinogen. More than 20% of the global emissions of this hydrocarbon come from coke production [2]. However, benz[ a ]pyrene accounts for no more than 1% of the polycyclic aromatic hydrocarbons produced; many of these are carcinogenic and mutagenic. Within the European Community, 16 compounds belonging to this group have been determined. Coke-industry wastes also contain considerable quantities of polycyclic aromatic hydrocarbons. It is important to study the distribution of such hydrocarbons in coke-industry wastes, with a view to evaluating the possible environmental burden and finding sources of pollution. Such problems arise in siting industrial waste stores [3] and also in creating new processing methods The following basic processing methods are employed for organic coke-industry wastes: use in coking batch, in highway construction for the creation of improved materials, and in the creation of new corrosion-protection media [4, 5]. Coke-industry wastes contain multicomponent mixtures of organic materials. Therefore, their investigation calls for sensitive and selective chromatographic methods of analysis. In the present work, the concentrations of polycyclic aromatic hydrocarbons are measured by highly effective liquid chromatography; light absorption is recorded using a photodiode matrix and fluorescent detection. Varian (USA) chromatographic equipment is employed: a 9012 high-pressure gradient pump with the possibility of creating a three-component eluent; a 9300 autosampler; a Polychrom 9065 detector based on a diode matrix. The mixtures are separated on a Varian (USA) ChromSpher PAH (4.6 × 250 mm) chromatographic column, specially developed for the effective analysis of polycyclic aromatic hydrocarbons. Chromatography is undertaken in gradient mode: acetonitrile‐water (from 70 : 30 to 100 : 0 for 10 min, 100% acetonitrile for 15 min). The solvent consumption is 1 cm 3 /min.
 
The content of polycyclic aromatic compounds—including the strong carcinogens benz[a]pyrene and dibenz[a,h]anthracene—in coke-plant wastewater is investigated. Biochemical purification permits the removal of the following polycyclic aromatic compounds: naphthalene, acenaphthylene, fluorene, acenaphthene, phenanthrene, anthracene, fluoranthene, pyrene, and benz[k]fluoranthene (79.6–99.9% removal); and benz[a]pyrene (65.7% removal). By contrast, biochemical treatment increases the content of the following compounds in the wastewater: benz[b]fluoranthene, benz[g,h,i]perylene, and indeno[1,2,3-cd]pyrene.
 
Empirical and analytical relations are established between the content of mineral inclusions Ml determined by petrographic analysis of the coal according to State Standard GOST 94.14–93 and the ash content A d of dry coal according to State Standard GOST 11022-95. In the empirical approach, statistical methods yield relations between Ml and A d in the form of regression equations for coals of a particular region and a system of beds with a complex set of minerals. In the more general analytical approach, Ml is divided into microcomponents (sulfides, carbonates, clay materials, quartz, etc.). Taking account of the densities of the components and their transformation on combustion, a quantitative relation between Ml and A d may be established for specific coals or their fractions in enrichment.
 
The radioactivity of Kuznetsk Basin coal and ash is considered, in relation to other regions.
 
Means of reducing the atmospheric emissions due to the wet slaking of coke are considered. One option, investigated here, is to remove residual active silt and organic compounds from the biologically purified wastewater sent for slaking, by coagulation and flocculation.
 
An automated power-metering system is developed, including the complete cycle from the collection of binary data by the meters to the presentation of the final production accounts in user-friendly form.
 
The development and introduction of automatic control systems in the basic production shops at OAO Zaporozhkoks is described.
 
Operational experience with the automatic control system for the desulfurization of coke-oven gas at OAO Magnitogorskii Metallurgicheskii Kombinat is considered. This system was designed by Krupp-Koppers. Problems with the control system are analyzed—in particular, problems typical of control systems with feedback and photometric instruments. In practice, perturbation-based automatic control systems are more likely to ensure reliable and stable operation of the desulfurization system, if the operator periodically corrects the parameters in the control algorithm on the basis of independent monitoring of the process.
 
Quantitative relations are found between the structural and chemical characteristics of macerals of the basic coal groups (vitrinite Vt, inertinite I, liptinite L), on the one hand, and their reflection coefficients R r and the corresponding dispersions σ R , on the other. For coal of a particular metamorphic stage, the reflection coefficient declines in the series I > Vt > L, on account of the reduction in aromatic chemical structure and in the degree of condensation of the aromatic blocks. In the metamorphic series, the reflection coefficients of the macerals rise; the values for Vt and L at intermediate stages converge. The dispersion of the reflection coefficients (and hence the reflectograms) is due to the spread in characteristics of the chemical structure of the coal’s organic content, as confirmed by calculations for the vitrinite of D, G, Zh, and K coal.
 
The activities of coal companies in the Russian Donetsk Basin (Rostov oblast) are considered, as well as the basic coal characteristics, the potential value of local reserves, and the prospects for the region in current economic conditions.
 
At OAO Alchevskkoks, two coke batteries (9A and 10A) with preliminary consolidation (ramming) of the batch have been introduced and successfully operated. These are the first such batteries to operate within the Commonwealth of Independent States. Dry slaking is used for the coke from battery 10A. The combination of rammed batch and dry slaking has yet to be adopted anywhere else in the world.
 
The practical literature regarding coal-batch formulation on the basis of rank is analyzed.
 
Heat-treated heavy tar from the high-seed pyrolysis of Kansko-Achinsk and Mongolian (Baganursk and Tugrugnursk) lignite may be used in coking. In that case, up to 7–10% 1OSV and KS coal may also be introduced in the batch. Adding the tar improves the gross coke yield and the physicomechanical properties of the coke.
 
The utilization of heat from coke-battery flue gases and other potential secondary energy resources in drying coal batch prior to coking is considered. The main factors that influence the thermal potential of the flue gases as a drying agent are identified. The reduction in moisture content of the coal batch prior to coking thanks to the coke-battery flue gases is calculated for different battery operating conditions. Technological principles for combining the drying of coal batch with its preparation by selective crushing and pneumomechanical separation are considered.
 
In September 2004, after reconstruction at OAO Nizhnetagil'skii Metallurgicheskii Kombinat (NTMK), blast furnace 6 went into operation for the production of vanadium from hot metal. At the startup of furnace 6, besides optimising its composition; it was decided to restore selective crushing of the coal batch using pneumatic and mechanical separation in the third unit of the coal preparation shop. Additional increase in the mechanical strength of coke by 1.5-2.0% was predicted with a 0.5-1.0% decrease in wear.
 
The basic industrial results obtained with thermal preparation of batch, followed by bed coking in horizontal furnaces, are briefly reviewed. Precarbon technology, which, in various forms, has been successfully used for many years, seems promising for the production of high-quality coke in a period of declining batch quality.
 
Improving blast-furnace production entails stricter requirements on the quality of metallurgical coke, so as to reduce its consumption in hot-metal production [1, 2]. Whereas previously these requirements reduced to improvement in ash and sulfur content, size (granulometric composition), and strength of the coke [3], the recent development of blast-furnace smelting with coal-dust injection [4] imposes requirements also on the reactivity CRI and postreactive strength CSR [5, 6]. The characteristics of the coke with the minimum possible consumption in the blast furnace are as follows: W r = 3‐5%; A d = 8‐9%; = 0.5‐1.0%; V daf = 0.3‐0.5%; 3‐5% of the >80 mm class; 3‐4% of the
 
Papers regarding Russia’s coke furnaces—in particular, their construction and reconstruction and issues of preservation and operational stability—presented at the Seventeenth Annual Seminar of Coke-Industry Specialists are summarized. The seminar was hosted by OOO EvrazKoksSibir’, a subdivision of OAO ZSMK.
 
The ecological and energy problems of coke plants are considered. Within that framework, a promising approach is to create an integrated system that includes the coke battery and a unit for utilizing the heat of its smokestack gases and removing their harmful ingredients.
 
Two types of dust-free coke-discharge modules are generally employed. The modules employed at OAO Zaporozhkoks are described and analyzed. Methods are proposed for determining their operational efficiency and testing their performance in plant conditions. Recommendations are made for improving the operational efficiency of dust-free coke-discharge modules mounted on door-opening machines.
 
Contributions to the Seventeenth Annual Seminar of Coke-Industry Specialists by representatives of companies that maintain Russia’s coke furnaces in operating condition are summarized. Problems in the provision of refractories for the repair and reconstruction of furnace linings are considered, along with new repair methods and the work of research and design organizations on improving coke production.
 
Pressure distribution in heating wall, Pa.  
Temperature distribution in heating wall, K.  
A three-dimensional model of the heating wall in a coke battery is developed by means of the Fluent CFD program. The results of simulation are in satisfactory agreement with experimental data. The mathematical model permits the maintenance of more uniform heating over the height, width, and length of the coke bed by regulating the combustion conditions. The model may also be used in modifying the heating-wall design in the coke furnace, boosting coke strength, reducing energy and fuel consumption, and reducing emissions.
 
Top-cited authors
Denis Miroshnichenko
  • National Technical University "Kharkiv Polytechnic Institute"
N. A. Desna
Dr. HP TIWARI
  • ArcelorMittal Temirtau
Prakhar Mishra
  • ABES Engineering College
Sujit Kumar Haldar