• Energy Research

ABSTRACTThis paper presents the results of a study on the influence of selected parameters of coal on the Hardgrove Grindability Index (HGI). The samples used in the investigation came from the same Polish coking-coal mine. The samples varied in terms of their quality parameters, i.e., volatile matter, ash content, chemical composition, maceral composition, and vitrinite reflectance). The influence of the aforementioned parameters on HGI was assessed. It was found that, among the investigated coals, the mean random vitrinite reflectance value, a measure of the coal rank, was the parameter that had the most significant effect on coal grindability (positive correlation). Such a correlation was also found for the carbon and vitrinite content. However, for volatile matter, liptinite, and total sulfur content, a negative correlation was found. The content and chemical composition of ash (as a reflection of mineral matter) has no significant effect on HGI. There were some weak negative correlations observed bet...

Coke is an integral component of the blast furnace charge; therefore, it plays an important role in the integrated steelmaking process. Achieving the required coke quality parameters by producers requires the use of a high proportion of the highest quality coking coals (hard coking coals) in the coking blends, which significantly increases the unit production costs. Approximately 75% of these costs are constituted by the cost of the coal blend’s preparation. There is a deficit in the best quality coking coals on the world market and their supply are characterized by large fluctuations in quality parameters. Therefore, from the point of view of the economics of coke production, it is advantageous to produce high-quality coke from a coke blend with the highest possible content of cheaper coals. The paper presents the results of the influence of coal charge bulk density and semi-soft coking coal content in the coking blend on the textural and structural parameters of coke, which determine its quality. Research has shown that the application of increased density influences the parameters of the texture and structure of the coke, which shape its quality parameters. The use of stamp-charging technology contributes to the improvement of the coke quality or enables the production of coke of a predetermined quality from blends containing cheaper semi-soft coals.

This paper presents the partial results of a study on obtaining compacted fuel from fine-grained coal fractions and biomass. The aim of the study was to determine the impact of selected parameters of the extrusion process and the applied binder (mechanical durability and density of the products). The fuels were formulated using the extrusion process. Raw materials used in the research were: Fine-grained coal (flotation concentrates), biomass (hydrolytic lignocellulose), and a wide spectrum of organic and mineral binders and their compositions. During the investigations, the variable factors were the following: Extrusion pressure, preparation of the mixtures for extrusion (mixing time and temperature of the mixture), composition of the extruded mixtures (share of fine-grained coal and biomass and type of binder). It was found that it is possible to extrude mechanically durable briquettes from mixtures containing fine-grained coal products and biomass. Under the conditions of the experiment, the most favorable mechanical durability was characterized by briquettes containing in their composition 90% of coal and 6% of biomass (in relation to the dry state). The briquettes with the most favorable physico-mechanical properties were obtained using organic binders—Starch (based on wheat and potato starch) and cellulose derivatives.

Carbon dioxide is emitted in several industrial processes and contributes to global warming. One of the industries that is considered a significant emitter is metallurgy. Therefore, it is necessary to search for and implement methods to reduce its emissions from metallurgical processes. An alternative option to the use of conventional coke, which is produced solely from fossil coal, is the utilization of bio-coke. The production of bio-coke involves the use of coking coal and the incorporation of biomass-derived substances such as biochar (charcoal). The article presents the results of the research on the influence of the biochar addition on the structural, textural, and technological properties of produced bio-coke. Research on the production and analysis of the properties of the obtained bio-coke aimed at assessing the potential possibilities of applying it in the process of a carbothermal reduction of manganese ore in order to smelt ferroalloys. Studies have shown that biochar addition to the coking blend in an amount of up to 20% allows a bio-coke characterized by properties enabling the mentioned use to be obtained. Bio-coke was characterized by higher CO2 reactivity index (CRI), lower post-reaction strength (CSR), and higher reactivity to synthetic manganese ore than regular metallurgical coke. In the context of industrial applications of bio-coke, it is necessary to verify its production and use on a pilot and industrial scale.

This paper presents the results of studies on the possibility of using lignite to produce blast furnace coke. The aim of the investigation was to evaluate the influence of lignite addition (direct addition or incorporated into briquettes) on the textural, structural and quality parameters (NSC-CRI and CSR) of blast furnace coke. It was found that the introduction of lignite in briquettes (4.5% addition) allows coke to be produced that is characterized by equally high NSC parameters as for coke obtained without lignite addition for standard top-charged operation.

Coke-making technology utilises two systems for charging the coke oven chambers with coal—a stamp-charged system (stamp-charging) and a gravity charged system (top charging). The presented study examines the impact of selected coal properties on the effectivity of the stamping operation by measuring the bulk density of the obtained stamped coal cake. An empirical mathematical model was developed that allows the forecasting of the coal cake density based on the most frequently assessed coal parameters, such as volatile matter, ash, moisture and particle size parameters, as well as the stamping operation parameter—cumulative stamping energy. The obtained results showed that the density of the stamped coal cake increases with the increase in the stamping energy (53.3 kg/m3 increase, for increase in natural logarithm value of 1), RRSB specific coal particle diameter d′ (6.4 kg/m3 increase, for each 0.1 mm increase in d′), ash content (8.9 kg/m3 increase, for 1% point increase) and moisture content (4 kg/m3 increase, for 1% point increase), and decreases with the increase in volatile matter content (3.82 kg/m3 decrease, for 1% point increase).

Protection of the natural environment is one of the most significant global challenges for the international community. World problems arising as a result of the incineration of fossil fuels, excessive CO2 emissions, erosion and soil degradation, as well as air pollution with the accelerating greenhouse effect and changes to the climate condition, make it necessary to take action at many levels. Environmental protection and the protection of natural resources need to follow the principles of sustainable development. Looking for alternative energy sources is appropriate but not sufficient and should be conducted in various areas since natural environmental changes are accelerating with many consequences. Therefore, there is demand for implementation of applications aimed at protecting air, and soil, preventing waste formation and combating the greenhouse effect. Therefore, the multi-directional use of various biocarbon substances for activities related to renewable energy, land reclamation, and carbon dioxide capture from the atmosphere is a promising and significant direction. This paper presents multidirectional analysis related to the use of biocarbon obtained from biomass and MSW waste.