Quality Of Metallurgical Coke Research Articles

Study on the Influence of Industrial Coke Oven Size on the Quality of Metallurgical Coke

The large-scale coke oven is a developing trend in coking technology, and the influence of the industrial coke oven size on the quality of metallurgical coke needs to be revealed. Under the same raw coals and blending ratios, metallurgical cokes were obtained from top-loading coke ovens with carbonization chamber heights of 6 and 7 m, respectively. The macroscopic quality and microstructure of the refined metallurgical cokes were comprehensively tested. The results showed that the conventional cold and thermal strength indexes of Coke-7m were better than those of Coke-6m. The comprehensive thermal strength at multiple temperatures further showed that the thermal strength advantage of Coke-7m was mainly manifested at low temperatures (1050 and 1100 °C) or a high temperature (1300 °C), where the solution-loss reaction mode of coke tended to be the “uniform reaction model” or “unreacted core model”. At medium temperatures, the solution-loss reaction mode tended to be the “gradient reaction model”, which had a greater destructive effect on the thermal strength of coke. At this time, the thermal strengths of the two cokes were close. Microstructure characterization revealed that industrial coke oven size mainly affected the carbon structure of coke but had little effect on pore structure. The advantage of Coke-7m regarding carbon structure is an important reason for its superior macroscopic quality compared to Coke-6m.

INVESTIGATING RELATIONSHIPS BETWEEN INTRINSIC PROPERTIES, PREPARATION PARAMETERS OF COAL AND COKE QUALITY: A SYSTEMATIC LITERATURE REVIEW

The purpose of this study is to review some of the key research concepts related to metallurgical coke. As the research landscape for coke metallurgy is evolving, researchers are increasingly interested in the effects of the intrinsic properties of coal, coal preparation parameters, and the technological conditions of coke production on the quality of metallurgical coke. As part of this review, a specific protocol, content analysis and thematic coding of cases of the “Preferred Reporting Items for Systematic Review and Meta-Analyses” method were used to investigate the simultaneous effect of these two parameters on the quality of coke in selected journal articles. A review of 118 articles was conducted, including their abstract, introduction, methodology, and results. According to the results of this study, coal blends and coal particle sizes have a direct effect on the three sections of coke mechanical properties, coke texture, and coke reactive properties. Reviewing various articles has shown that the presence of fatty coals in smaller size distribution, combined with largersized weak coals, leads to the formation of a stronger structure in the produced coke. However, this does not guarantee an improvement in the coke reactivity parameters. On the other hand, increasing the blending ratio of coking coals in the final mixture for producing normal-sized coke (dimensions smaller than 3 millimetres) improves the coke reactivity parameters. Studies investigating coke structure have demonstrated that a cohesive mosaic structure in high-quality cokes results from well-distributed maceral blends of coking coals with optimal size distribution among other coals.

Quality of Metallurgical Coke Produced with Additives Derived by Thermal Dissolution of Coal

Quality of Metallurgical Coke Produced with Additives Derived by Thermal Dissolution of Coal

Production and characterization of metallurgical coke from duduguru coal

This work illustrates the production and characterization of metallurgical coke from Duduguru coal, Obi local Government Area of Nasarawa State, Nigeria. The analytical assessment of properties such as proximate analysis, elemental composition, and calorific value are very important to know the coking qualities of the coal. The proximate analysis showed that the moisture content, ash content, volatile matter, fixed carbon and calorific values of the coal are; 1.86%, 18.82%, 43.74%, 53.58% and 5405.15 Cal/g respectively. Based on the result of the proximate analysis, the coal is of good metallurgical coke quality from an industrial prospective and heat generation is to be considered. Elemental analysis shows that due to the low heavy metals, low sulfur content and ash content of the coal, utilization of the coal within a safe environment is feasible with just a little environment impact and make it suitable for blending with strong coking or caking properties. Â

Influence of the Heating Rate on the Quality of Metallurgical Coke.

Four bituminous coals of different origins and ranks and one industrial coal blend were carbonized at a semi-pilot scale at various temperatures to study the effect of heat treatment (i.e., different heating rates) on the structural evolution and hence the subsequent reactivity of the resulting cokes and their mechanical strength. The development of the coke microstructural order under different thermal treatments during carbonization was assessed by means of Raman spectroscopy. The results indicated an improvement in the structural order with increased operating temperatures and hence increased heating rates and a decrease in the active sites. The quality of the cokes was determined by means of the Japanese Industrial Standard (JIS) and the Nippon Steel Corporation (NSC) tests. In addition, the apparent reaction rate of cokes was measured using a fixed bed reactor. The increase in the heating rate during carbonization led to cokes with a lower mechanical strength and apparent reaction rate. Good correlation was found between the apparent reactivity of cokes and the coke strength after reaction.

Quality evaluation of metallurgical coke produced with sawdust and different mixtures of coal

Abstract The present research is dedicated to analyzing the addition of sawdust biomass, which is a carbonaceous raw material that may be used in coal blends for the production of metallurgical coke, preserving the required quality, with lower cost. The quality of metallurgical coke may be determined by the efficiency of its chemical, physical and thermal functions inside the blast furnace. For the production of hot metal, any modification in the constituents of the raw materials may have a direct influence on the blast furnace productivity and in the final quality of steel. From the thermal degradation analyzes such as coke reactivity index (CRI) and coke strength reaction (CSR), cold resistance (DI) and immediate analyzes, it may define the quality of metallurgical coke produced with biomass aiming at relating the parameters that interfere in the particularities of the material function in the blast furnace. Some results show that it is possible to use 2% of eucalyptus sawdust in the coal mixture.

Coke Quality and the Prospects for Coking with Proprietary Coal Concentrates at AO EVRAZ NTMK

Abstract—The main suppliers of coal for coke production at AO EVRAZ NTMK are considered, along with the technological value of each concentrate in systems with wet and dry quenching. Alternative suppliers may be identified by ranking the concentrates. Laboratory and industrial coking reveals the influence of the coal concentrates on the quality of metallurgical coke. On that basis, their ideal content in the coking batch may be determined.

Effect of high petroleum coke additions on metallurgical coke quality and optical texture

Abstract The objective of the present study was to evaluate the effect of high additions of petroleum coke on the rheological properties of coking coal and the quality of cokes produced on pilot scale at the Usiminas R&D Center. For this purpose, blends using petroleum coke additions of 5%, 10%, 20%, 30% and 40% were produced. The results showed that the blends were able to satisfactorily absorb up to 30% of petroleum coke, keeping the quality (DI, CRI and CSR) similar to the industrial mixture. The observed main textural components were: mosaic, fragmentary, fusite and anisotropic inert. In general, before CRI, cokes showed good cohesion, with the petroleum coke having been absorbed by the coke matrix. After the reaction with CO2, there was verified a preferential consumption of the textures fusite, fragmentary and anisotropic inert due to the Boudouard reaction, besides the deterioration of the interfaces between the petroleum coke and coke matrix. In addition, the results showed that the increase of mosaics contributes to the increase of cokes DI15-150 and CSR. Finally, for the coal blend employed, it is suggested the utilization of a maximum of 30% additions of petroleum coke.

An efficient method of foundry and metallurgical coke quality improvement

At foundry coke production, introduction into a coal burden comparatively small amount of non-sintering carbonaceous additives is one of effective methods of the coke mechanical, physical and chemical properties intended control. A review of industrial tests on coal burdens coking with different thinning additives, carried out at coking plants of Western Siberia and the Urals, presented. Coke dust of coke dry quenching facility was used as additives, as well as oil-coke and semi-coke fines, and rubber crumb. Under industrial conditions of JSC “Altaj-koks” and JSC “Koks” coke dust of coke dry quenching facility was tested as a thinning additive. After introduction into the burden of 1.6–3.0% of coke dry quenching facility dust, the coarseness and mechanical strength of foundry coke increased. The industrial burden coking with oil-coke fines was accomplished at JSC “Altajkoks” Nos 1 and 2 coke-oven batteries. Oil-coke fines in the amount of 5% was added to a burden (у = 15–16 mm) without change of coking regime (the period of coking is 15–16 h). Strength of foundry coke (М40) increased by average 0.5%, of BF coke – by 1.2%, ash content decreased by 0.3%, sulfur content increased by 0.03–0.06%, reaction ability decreased by 19% (rel.). At the OJSC “Gubakhinsky koks” it was determined by industrial tests, that it is possible to produce a metallurgical coke, meeting requirements of non-ferrous metallurgy, providing up to 5% of oil-coke fines are added instead of the same amount of low-sintering coals. VUKHIN’ studies showed, that still higher effect in improving foundry and BF coke quality can be reached by introducing into the coal burdens “modified” oil coke up to 50% as a coking additive. During industrial tests at JSC “Altaj-koks” semi-coke fines were introduced into production burden instead of KCH coal in the amount of 3–7%. At its utilization a burden crushing degree decreased down to 76.5%, dust content (class 0.5–0 mm) decreased down to 39.1%, its bulk density increased up to 780 kg/m3 . At that the coke mechanical strength corresponds to that for coke made of industrial burden, and its coarseness increased. Results of successful industrial tests of foundry coke made of burdens with coke dry quenching facility dust and oil coke fines at smelting in cupola gray cast iron and malleable cast iron.

Development of energy saving technology of coke dry quenching

Application of coke dry quenching technology provides saving of energy resources, decreasing of environment pollution and increase of metallurgical coke quality. Despite of advantages of coke dry quenching facilities, an additional quantity of circulating gas is generated because of quenching technology peculiarities. This additional circulating gas must be released out of the cooling agent circuit resulting in environment pollution. Existing and proposed methods of reduction of emissions into atmosphere of excess circulating gas considered. It was shown, that utilization of the excess circulating gas as a fuel is the most effective solution of the considered problem. The solution comprise stabilization and support of combustible components composition in the circulating gas at the level of approved indices, joining of excess gas flows out of the dry quenching facility chambers, it enrichment by some amount of high calorie gas (coke or natural) and supply to gas uses. This technical solution was first realized by ArcelorMittal at the coke plant of the steel-works after E. Zendzimir in Krakov, Poland. In 2017 at the EVRAZ NTMK coke plant a project of the dry coke quenching facility modification was realized, comprising utilization of excess circulating gas, which has a considerable technical difference comparing with ArcelorMittal project. According to technology flowsheet, the excess circulating gas is collected out of operating chambers into a collector, cleaned of dust in a bag filter, chilled, enriched by a high calorie gas and delivered into the gas pipe of BF gas for further utilization as a fuel. To increase efficiency of the technology and to reduce the natural gas consumption for calorie content of enriched gas stabilization and supply it into the BF gas pipe line, the CO and H2 content in the circulating gas of the coke dry quenching facility is kept at the level of 12–15 and 4–5 % correspondently. Implementation of the technical modification of the coke dry quenching facility with elimination of harmful substances emissions within the excess circulating gas provided decrease of harmful substances emissions at JSC EVRAZ NTMK – 4 kg per ton of steel.

A review of ironmaking by direct reduction processes: Quality requirements and sustainability

Abstract Currently the majority of the world’s steel is produced through either one of the two main routes; the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route. In the former, the blast furnace uses iron ore, scrap metal, coke and pulverized coal as raw materials to produce hot metal for conversion in the BOF. Although it is still the prevalent process, blast furnace hot metal production has declined over the years due to diminishing quality of metallurgical coke, low supply of scrap metal and environmental problems associated with the process. These factors have contributed to the development of alternative technologies of ironmaking, of which Direct Reduction (DR) processes are expected to emerge as preferred alternatives in the future. This study reviews the different DR processes used to produce Direct Reduced Iron, providing an analysis on the quality requirements of iron-bearing ores for use in these processes. The study also discusses the environmental sustainability of such processes. DR processes reduce iron ore in its solid state by the use of either natural gas or coal as reducing agents, and they have a comparative advantage of low capital costs, low emissions and production flexibility over the BF process.

THE MAIN TRENDS IN THE DEVELOPMENT OF WORLD COKE-CHEMICAL INDUSTRY AT THE PRESENT STAGE

Materials describing the current state of the global coke industry and the main trends of its development are represented. Data on production of major coke producers in the world are also represented. It is shown that the slowdown of technical development of coke industry requires to compensate it by creating of flexible towards to coal base technology, which would contribute to produce coke of desired quality, reduction of cost production and reduce environmental pollution. Shown special significance of use of technology of coke dry quenching in coke production and the role of SE «GIPROKOKS» in the development and improvement of this energy saving technology, its promotion on the world market. Are considered the main technological aspects of two-products technology of coke production, that provide in addition to obtaining the coke as the main product to produce coke-oven gas containing more than 60 % hydrogen and 30 % carbon monoxide. Receiving the coke oven gas of a specified composition allows to significantly expand the scope of its application. Are considered technology directed to the expanding of coal raw materials base of coking and improving the quality of metallurgical coke. Bibl. 6, Fig. 2, Tab. 2.

Statistical assessment of coal charge effect on metallurgical coke quality

Statistical assessment of coal charge effect on metallurgical coke quality

Quality assessment of metallurgical coke: Fast determination of reactivity and postreactive strength

The quality of metallurgical coke may be assessed on the basis of technical analysis, the granulometric composition, mechanical strength, reactivity, structural strength, density and porosity, postreactive strength, and other characteristics. Analysis shows that the strength characteristics of coke in the cold, heated, and subsequently cooled states are closely correlated. Methodological and technological deficiencies of the determination of CRI and CSR are outlined. An express method of determining coke quality is developed. The postreactive strength determined by the method proposed at the central laboratory for coke production at OAO EVRAZ NTMK is shown to be closely correlated with the reactivity (CRI) and postreactive strength (CSR) determined in accordance with the ASTM standard. Accordingly, by the proposed method, the reactivity of the coke and its strength after reaction with carbon dioxide may be predicted with high probability.

Assessing the quality of metallurgical coke by Raman spectroscopy

Metallurgical coke should be resistant to mechanical, thermal, and chemical influences. This resistance is related to the structural order of the organic constituents. Raman microspectroscopy of carbonaceous matter (RSCM) is demonstrated as a promising tool to investigate this property. Variations of the microstructure among samples with different quality parameters are detected by analyzing the Raman spectra collected on their individual coke lumps. Three basic types of Raman spectra are discriminated. Their predominance in a bulk sample predicts roughly the coke quality, estimated by an ISO standardized test. To investigate the structural behavior of coke in a blast furnace, several samples have been treated under typical gas atmospheres of the blast furnace process (carbon dioxide, nitrogen) at temperatures between 850°C and 1100°C for 120min. RSCM data measured on the treated lumps evidence a progressive transformation of poorly ordered organic microstructure towards a higher structural order.

Efficient way to use of non-coking coals in non-recovery coke making process

Maximization of non-coking coal in coal blend is eloquent interest among re- searchers in coke making throughout the world. To maximize the non-coking coals in coal blend with the scarce and expensive coking coals is an essential practice in the iron and steel industry. The fundamental aspect of the coal blending theory of low value coals to produce good quality of metallurgical coke in non-recovery coke making process was investigated in this study by using the composite coking potential technique. The implementation of the technique has yielded use of up to 25% pulverized coal injection, 20% raw petroleum coke as a component of coal blend. Results show that the coal blend having composite cok- ing potential value of 4.8 is desired to achieve the targeted coke strength after reaction of 65.

Influence of biomass on metallurgical coke quality

Two industrial coal blends used in coke making were subjected to tests in order to assess the influence of waste sawdust (SC2 from chestnut and SP1 from pine) on the quality of the coke produced. The biomass was added in quantities of up to 5wt.%. It was observed that biomass produced a substantial decrease in the plastic properties of the industrial coal blend, with reductions in Gieseler maximum fluidity of around 50% for 3wt.% additions of the two different sawdusts. Carbonizations with sawdust additions ranging from 0.75 to 5wt.% were carried out in a movable wall oven of 17kg capacity. The bulk density of the charge was observed to decrease with increasing amounts of sawdust with negative consequences on the quality of the cokes produced. Mechanical strength was determined by means of the JIS test. Coke reactivity and post-reaction strength (CRI/CSR indices) were also assessed. The amount of sawdust added was low to prevent any deterioration in coke quality. The advantage of using biomass in coking blends should be seen as a possible way to reduce costs and CO2 emissions and to incorporate alternative raw materials in coke production.

Development of New Coal Blend Preparation Methodologies for Improvement in Coke Quality

Coal preparation has become a very important technique for preparation of high-quality metallurgical coke, the quality characteristics of which play a major role in the performance and economics of blast furnaces. Since availability of good quality metallurgical coals are meager in India, coal charge blends for carbonization in slot-type coke ovens are prepared from blending of various indigenous and imported sources of diverse characteristics. Preparation of coal blends for carbonization assumes paramount importance in terms of cost, quality, and resource utilization. Judicious coal-blending techniques based on intrinsic quality parameters coupled with various precarbonization steps to maintain blend homogeneity, granulometry, caking and coking properties of the blend are practiced under Indian conditions. The quality of metallurgical coke depends on type of coal, its physico-chemical properties including its granulometry, and its thermochemical behavior. Quality parameters of coke produced from a particular coal blend can be significantly influenced by the coal preparation technique adopted particularly when the blend comprises several sources of diverse quality parameters. Groupwise crushing of coal was developed with the aim to reduce the heterogeneity of different size fractions in terms of distribution of inerts and reactive contents. The groupings were based on their grindability indices, caking/coking properties, and dilation properties of individual size fractions. This article discusses in detail new coal preparation methodologies for improvement in coal charge blend granulometry and flowability, reduction in microfines content, and improvement in blast furnace coke quality.

Coal for metallurgical coke production: predictions of coke quality and future requirements for cokemaking

This paper reviews quality requirements of metallurgical coke for the blast furnace, coke structure, and relationships between structure and quality. Models of prediction of metallurgical coke quality parameters based on maceral composition and properties of coals being carbonized are summarized. Early prediction models of cold coke strength and the development of second-generation hot-strength prediction models based on parameters as coke reactivity index (CRI) and coke strength after reaction with carbon dioxide (CSR) are assessed. The review concludes with an assessment of current coke production and coal demand in the steelmaking industry, globally, followed by a preview of possible future alternative coking technologies.

History of applied coal petrology in the United States: I. Early history of the application of coal petrography in the steel industry

In May of 1992, a seminar entitled “An Oral History of Applied Coal Petrography and the Triangle Run” was held at Southern Illinois University, Carbondale, for the purpose of recording the personal accounts of four of the principal scientists involved in the initial application of coal petrology to the manufacture of metallurgical coke and subsequent developments. The four scientists included William F. Berry, Ralph J. Gray, William Spackman, and Richard R. Thompson. Under the direction of Dr. William Spackman, founder of the Coal Research Section at The Pennsylvania State University, innovative fundamental studies of the properties and thermal behavior of coal and coal macerals resulted in the development of integrated coal and coke research programs and laboratories at US steel companies. These studies also stimulated the beginnings of a series of fruitful collaborations between industry and universities. Unique among these cooperative efforts was the free exchange of information that took place over a period of 25 years when scores of people interested in the practical applications of coal petrology traveled to confer with researchers and technicians at US Steel, Bethlehem Steel, and the Coal Research Section (the “triangle run”). Prof. Spackman's students, as well as students of other universities, became the developers and managers of company-specific petrographic classification and prediction systems used to control the quality of metallurgical coke and to formulate coking blends. These systems allowing each company to evaluate and utilize their own or other available coals are still in use today.