Volatile Matter Yield Research Articles

Coal chemistry, utilization potential, and coalbed methane (CBM) assessment of some coal deposits in Central Benue Trough, north-central Nigeria

Coalbed methane (CBM), a current global legislative priority for climate change mitigation, is an unconventional and eco-friendly clean source of energy that is considered a veritable alternative to conventional fossil fuels. Despite its overwhelming advantages, CBM evaluation studies of Nigerian coals have received little or no attention. To bridge the gap in knowledge, we have for the first time in Jangwa-Shankodi and Lafia-Obi, described the potential of harnessing CBM for its gainful utilization in Nigeria using some coal deposits in its north-central region as a case study. The gas contents of the coals were determined empirically by taking account of their ultimate and proximate properties. Other coal parameters such as fuel ratio and vitrinite reflectance (Ro (%)) have also been computed and discussed. Proximate analyses of the studied coal samples show moisture contents that vary between 2.28 and 2.56%, whereas, volatile matter yield is placed in the range of 29.98–30.34%. Ash yield ranges from 7.83 to 8.64%. Fixed carbon content varies from 55.97 to 56.30%. Variation in fuel ratio shows a restricted range from 1.72 to 1.87. All the coal samples were found to be low in sulphur (< 1%) with H/C ratios that vary from 0.072 (LAF 2, 3 and 4) to 0.086 (JSK 3). Moreover, the coals were found to be of medium-volatile bituminous rank, with gas contents that range from 12.65 to 13.20 cc/g. In the current study, kerogen lies in the Type IV zone, which suggests the generation of methane gas by the studied coal samples. Also the estimated range of vitrinite reflectance (Ro) which varies between 1.073% and 1.086% indicates thermogenic gas expulsion in the coals. There is a noticeable increase in gas content with coal maturity and depth. These values are indicative of good quality coals that show antecedents for CBM production. However, considering that this work is a pilot study, we recommend that core drilling be employed in obtaining insitu measurements of the coal gas contents and thus, verify these empirical estimates. Also, detailed laboratory study on pore structure (and its distribution) and adsorption isotherm curve are recommended to better understand the coal reservoir properties and hence, consolidate the present study.

IMPROVING THE QUALITY OF EKIBASTUZ COAL USING THE DRY ENRICHMENT METHOD

This paper discusses the possibility of improving the ekibastuz coal quality through the use of "dry enrichment" technology. The experiments and calculations carried out made it possible to determine the optimal scheme for enrichment of samples of thermal coals from the Ekibastuzsky open-pit mineof "Angrensor-Energo" LLP. Testing of technical characteristics, such as moisture content, ash content, volatile matter yield and calculation of energy characteristics of enriched samples of thermal coal was carried out in 3 stages in a coal chemistry laboratory. As a result, it was found that the energy content of the enriched fuel samples increased to 28.5% of the original. This significantly improved consumer properties by obtaining the maximum yield of high quality coal concentrate. Consequently, the developed scheme of enrichment allows to significantly reduce the consumption of electricity, reduce emissions into the atmosphere, reduce the harmful impact on the environment, and expand the markets for coal.

The influence mechanism of ionic liquids on the ash melting and combustion characteristics of Zhundong high-alkali coal

ABSTRACT This study investigated the ash reduction and quality improvement effects of four types of ionic liquids on Zhundong high-alkali coal, focusing on the evolution laws of coal ash melting and combustion performance under the ionic liquid system, which provided a theoretical basis for the subsequent utilization of high-alkali coal. Ionic liquids can effectively reduce inorganic mineral content and volatile matter yield, increase fixed carbon and oxygen content in coal, and reduce hydrogen and sulfur content. The silicon-aluminum ratio of coal ash increased, and the content of low-melting minerals in coal ash decreased, while the content of refractory minerals increased, leading to an increase in the melting temperature of coal ash. Ionic liquids can inhibit the oxidation reaction of coal, which is beneficial for suppressing spontaneous combustion of coal and improving safety during storage and transportation.

Non-graphitic carbon as sodium-ion battery anode materials with improved ratio of plateau to sloping capacities prepared from lignite-based organic maceral

Herein, huminite concentrate is obtained from lignite with high yield of 68.9 % by density gradient separation, subsequently converted to non-graphitic carbon (HM-H) by carbonization at 1400 °C for 2 h. Huminite concentrate possesses relatively high oxygen content and considerable amount of aromatic component, with modest yield of volatile matter during pyrolysis, resulting in optimized carbon phase distribution and enhanced electrical conductivity of HM-H. Compared with HM prepared by direct carbonization of lignite, HM-H has slightly higher contents of pseudo-graphitic and graphite-like carbons, and lower content of highly disordered one. Notably, HM-H exhibits remarkably improved electrical conductivity (1773 S m−1) than HM (1406 S m−1). Compared with HM anode for SIBs, HM-H one delivers higher plateau capacity (170.1 mAh g−1) meanwhile lower sloping capacity (91.8 mAh g−1), with significantly improved rate and cycling performances. Full cell assorted with NaFe1/3Ni1/3Mn1/3O2 cathode and HM-H anode demonstrates higher energy density of 210.5 Wh kg−1 than its counterpart (193.8 Wh kg−1) at 20 mA g−1, with superior rate performance (208.6 mAh g−1 at 200 mA g−1) and a capacity retention ratio of 89.7 % after 100 cycles. This work provides a facile and effective strategy for preparing non-graphitic carbon as high-performance anode materials for SIBs.

Розробка оптимальних складів вугільних шихт для трамбування. повідомлення 1. дослідження сировини щодо можливості її використання в трамбованих шихтах

It is shown that the coal used for coking with the tamping technology should be characterised by a low basicity index, the necessary levels of sintering and tamping to achieve cake stability when it is loaded into the coking chamber. Based on this, a comprehensive study of the properties of 15 components of hard coal charges (13 coal concentrates, sludge and flotation concentrate) was carried out in terms of their prospects as a raw material base using the technology of tamping coal charges. The analysis of the obtained results is presented. In particular, the evaluation of the shear strength of coal concentrates showed low values (from 9.6 to 12.6 kPa) of the shear force for all the studied samples. The strength of rammed cakes made from fine additives is significantly higher (σzz of flotation concentrate is 15.8 kPa, and sludge is 14.9 kPa), so an increase in their content in the charge will have a positive effect on the strength of the rammed cake. It has been established that the most accurate of the studied coal quality indicators, the tamping index σzz, is predicted by the Hardgrove rejuvenation coefficient and the thickness of the plastic layer. Prediction by volatile matter yield and free swelling index FSI is possible with medium accuracy, while the vitrinite reflection coefficient, Horn index and maximum compression index of Odibert-Arnoux are inaccurate. The heterogeneity of the samples for all the studied indicators characterising the fluid-plastic properties of coal was revealed. The optimums of the function of the tamping index were calculated, which are achieved at the following quality indicators: Vdaf = 25.7 %; Y = 14.3 mm; HGI = 69.6 units; R0 = 1.17 %; RI = 37.9 units; a = 1.9 %; FSI = 2.6 units. It was established that the optimum ramming properties are achieved at the values of classification indicators corresponding to coking coal. A positive feature of the tamping technology is the possibility of ensuring the specified set of properties by using not expensive and scarce coking coal, but a mixture of cheaper grades of low-baking, petrographically heterogeneous coal.. Keywords: coal, coal concentrates, coking, tamping, technological properties, testing, plastic-viscous properties, Hardgrove threshold. Corresponding author Miroshnychenko D.V., e-mail: dvmir79@gmail.com

Концептуальное проектирование базы данных углей на основе общих генетических признаков

The operational efficiency of coal-fired thermal power plants designed to utilize designed / standardized fuel and coking plants largely depends on the quality characteristics of the supplied coal products, the main indicators of which are: calorific value, ash content, moisture content, volatile matter yield, sulfur and nitrogen content, particle size distribution. Coal of various grades is mined in Russia, but not more than one third can be classified as the designed fuel. Accordingly, there arises a need to make fuel mixtures with specified parameters. The article justifies the topicality to create a database of qualitative characteristics and indicators of various coal grades. Using the results of analytical review of normative documentation, coal classification options have been developed based on the list of quality indicators specified in the state standard for identification of coals and coal products. Logical structure of the data, entity, relationships between them, attributes and constraints have been defined at the design stage of the database. The type and content of the conceptual model are presented as an ER-model visualized in the form of a graphical notation of the entity-vs-relationship diagram. Based on the analysis performed, ways of transaction and input data sources for the supplied coal characteristics and processing technologies have been defined. Examples of data structure in the models of individual entities and methods to determine their parameters have been provided.

Petrographic and geochemical analysis of Barmer Basin Paleogene lignite deposits: Insights into depositional environment and paleo-climate

The current study attempts to characterize the samples from Kapurdi, Giral and Sonari lignite mines of Barmer Basin within Rajasthan Tertiary Lignite deposits using petrographic and geochemical techniques. The data generated has been studied in order to better understand the geochemical properties, hydrocarbon potential, depositional environment and paleo-climatic condition of the paleo-mires of these lignites. The proximate analysis of the samples reveals that the average ash content of the Barmer Basin is 11.93 %, the average moisture content is 14.08 %, average volatile matter yield is 42.03 % and the average fixed carbon is 31.95 %, which suggesting that the physical properties of lignite are dominated by volatile matter on dry basis. The ultimate investigation reveals the chemical properties of the lignite with the average carbon content found to be 58.79 wt%, hydrogen value 3.83 wt%, nitrogen percentage 1.60 wt% and sulphur content 2.75 wt%. This clearly indicates high sulphur concentration in Barmer lignite deposits, based on dry basis. The lignite samples subjected to FTIR studies identified aliphatic CH group, aromatic CO group, hydroxyl OH and Aldehyde HCO group. The Rock-Eval pyrolysis studies have been carried out to know the coalification profile of the deposits and hydrocarbon source rock potential. The varying behaviour between brown coal lithotype are primarily reflected by changes in oxygen index values, whereas hydrogen index values demonstrate a more pronounced correlation with coal type rather than the level of maturation. The results show the average total organic carbon (TOC) 47.29 %, S1 peak 2.18 mg HC/g, S2 peak 88.70 mg HC/g, S3 peak 19.22 % mg CO2/g, Tmax 410.53 °C, hydrogen index 219.2 mg HC/g TOC and oxygen index 46.33 mg CO2/g TOC. According to petrographic investigations, the huminite macerals dominate followed by liptinite and inertinite maceral groups in mineral matter-free basis. In all the three different lignite mines, the huminite group dominates with preserved sub-maceral ulminite indicating less transformation of structured plant matter. Reconstruction of depositional environment and paleo-climatic condition of the paleo-mires has been attempted by using organic petrographic indices. The high gelification index (GI) and low tissue preservation index (TPI) values suggest a prolonged wet environment during the decomposition of organic material, accompanied by a gradual subsidence process. The ground water influence index (GWI) and vegetation index (VI) denote ombrotrophic to mesotrophic hydrological conditions of basin at the time of deposition.

Modified network kinetic model for coal pyrolysis with high-value products and low carbon emissions

Pyrolysis is a clean and efficient technology for the conversion of low-rank coal. Its key product is tar with high value. The complex composition of tar limits its further effective utilization. Although most kinetic models can provide the final distribution of three-phase products in coal pyrolysis, an effective prediction method for the specific composition of tar and gas has not yet been developed. Most numerical models serve to improve the total yield of volatile matter and cannot provide theoretical guidance for the improvement of tar quality or the reduction of carbon emission. Based on the basic assumptions of the CPD (Chemical Percolation Devolatilization) model for product molecules structure and generation mechanism, this paper proposed a more sophisticated method for dividing tar composition, which can achieve the division of light, medium, and heavy fractions of tar components according to boiling point. Light gas composition could be obtained with the combination of FG(Functional Group) submodel. The influence of pyrolysis final temperature, heating rate, and environmental pressure was explored for the yield and distribution of products of 18 coals. The simulation results showed that the total yield of tar was affected by both coal structure characteristics and operating parameters. Under conditions favorable for evaporation, such as low pressure and high temperature, the total yield of tar was positively correlated with the average aromatic core size in coal. Under other conditions, tar release was limited by its volatility. Coal with larger average aromatic core size corresponded to less tar yield instead. The pressure in the operating parameters had the most significant influence on the total yield of tar. The heavy fractions of tar are more sensitive to changes in operational parameters, making working conditions that increase the total yield of tar reduce tar quality. The overall carbon emission of pyrolysis is <1 kg CO2/kg tar, which is far lower than the 2–4 kg CO2/kg tar and 3–9 kg CO2/kg tar of direct and indirect liquefaction processes. Under the conditions of sufficient insulation time and no consideration of secondary reactions, the carbon emission of pyrolysis only depended on the content of carboxyl groups in the precursor functional groups. Therefore, the carbon emission intensity decreased with the increase of coal rank. For the optimization for total tar yield and tar quality, 1 atm pressure and 723–923 K temperature was optimal for low rank coals, while low temperature and heating rate with 10–20 atm pressure or high temperature and heating rate with 45–50 atm pressure were optimal for medium rank coals. For the optimization of light tar yield and tar quality, 6–9 atm pressure was optimal for low-rank coals, and 1–3 atm pressure was optimal for medium-rank coals.

Regularities of changes in pitch characteristics when varying the parameters of PJSC “KOKS” coal tar distillation

The regularities of changes in the main characteristics of coal tar pitch (softening point, ash content, volatile matter yield, content of α-, α1-, α2-, γ- and β-fractions) obtained by coal tar distillation, were studied changing three process parameters – tar heating rate, temperature and duration of isothermal exposure. The mathematical model obtained in the form of regression equations satisfactorily describes the dependence of the studied pitch characteristics on the coal tar distillation process parameters and can be used to predict the quality of the resulting coal tar pitch.

Microstructural diversity and digestion yields of select bituminous and subbituminous coals as raw material candidates for carbon fiber precursor production

This work investigates the use of coals as raw materials for carbon fiber precursor production as a new alternative to coal utilization. Coal being a highly complex and heterogeneous material with different macerals and minerals complicates this task. Extensive microstructural characterization as well as preliminary digestion studies are performed on three bituminous coals (Herrin and Springfield from the Illinois Basin and the Blue Gem from the Central Appalachians) and one subbituminous coal from the Powder River Basin (Monarch), as raw material candidates. The subbituminous coal was richer in oxygen, lower in sulfur, and had a higher volatile matter yield. Microstructural investigations were performed using X-ray diffraction, X-ray/neutron computed tomography, scanning electron microscopy with energy dispersive spectroscopy, and petrology. Mild solvent extraction studies were conducted using creosote and decant oil as solvents in microreactors. The extraction yield was sensitive to temperature and time (350 to 450 °C between 30 and 120 mins.) for both creosote and decant oil digestions. While the Blue Gem coal had more desirable microstructural properties with less mineral content and cleaner macerals, it had the lowest coal conversion to quinoline soluble ‘liquid’ (of the bituminous coals). The lower coal conversion yield was hypothesized to be connected to the lack of FeS2 which could act as a catalyst when Fe is liberated from the structure under solvent extraction conditions. The Herrin and Springfield coals revealed similar microstructures and coal conversion efficiencies (higher than Blue Gem). These coals were the most promising candidates for further examination from this first approximations study. The subbituminous Monarch coal, however, was deemed less suitable due to poor coal conversion and less desirable microstructures. Additionally, the presented results with combined microstructural data from multiple length scales established a framework necessary for a first approximations study in this new coal utilization approach.

Method for determining the ultimate sorption capacity of coal matter by EPR-spectroscopy

Purpose. Improving the method for determining the ultimate sorption capacity of coal matter using EPR-spectroscopy (electron paramagnetic resonance) by adjusting the proportionality coefficient between the ultimate sorption capacity of coal and the concentration of paramagnetic centers and the conjugation coefficient in accordance with the degree of coalification. Methodology. The ultimate sorption capacity of the matter was estimated by EPR-spectroscopy, based on the content of paramagnetic centers (PMC) in coal, which are able to come into physical (sorption) interaction with molecules of paramagnetic gas (O2) when the pressure increases. Processing of the research results was carried out by methods of mathematical statistics. Findings. Analysis of long-term results for determining the ultimate sorption capacity of coal matter by EPR-spectroscopy was carried out. The analysis testified about the need to adjust the proportionality coefficient  between the ultimate sorption capacity of coal and the concentration of paramagnetic centers Na and the conjugation coefficient Ksc, depending on the coal rank metamorphism. The values of the proportionality coefficient  by hard coal ranks for the yield of volatile components Vdaf and the reflectivity of vitrinite R° were calculated. Appropriate changes were made to the express-method for estimating the ultimate sorption capacity of coal by the EPR method. Originality. It is proved that the proportionality coefficient β between the ultimate sorption capacity of coal and the concentration of paramagnetic centers Na and the conjugation coefficient Ksc is not a constant value, but changes (decreases) with the degree of metamorphism. It is established that this relationship is satisfactorily characterized by the sigmoid model, whose inflection (on the graph) is confined to the gas and fat ranks of coals (volatile-matter yield is 29 %) and is caused by the second main jump of coalification during a cardinal change in the molecular structure of coal, associated with the completion of the intensive decomposition of the polymer-lipoidin component in the coal matter. Practical values. The express-method was improved for estimating the ultimate sorption capacity of coal by the EPR-method, which differs by specified proportionality coefficients according to ranks in the series of coalification.

Визначення теплоти згоряння рослинної сировини та деревинного вугілля.

DETERMINATION OF THE CALORIFIC VALUE OF PLANT MATERIAL AND CHARCOAL © D.V. Miroshnichenko, Doctor of Technical Sciences, I.K. Malik (National Technical University "Kharkiv Polytechnic Institute", 61002, Kharkov, Kirpichev str., 2, Ukraine) It has been shown that the calorific value of plant material is related to its elemental composition, in particular the content of carbon, hydrogen and oxygen. Different types of plant material are characterized by different elemental compositions and, therefore, have different calorific values. The purpose of the work presented in this article was to establish the relationship between the data of rapid analysis (moisture, ash content, volatile matter yield, non-volatile carbon content) and elemental (carbon, hydrogen, nitrogen, sulfur, oxygen) composition of various types of plant material and charcoal with the value of their higher heating value, as well as the impact of changes in the indicators of technical and elemental analysis on the value of the higher heating value of the studied samples. For the analysis, we used a unique database containing information on the composition and properties of plant material that can be used for the production of biogas, charcoal and torrefied biomass. A total of 362 samples were analyzed. Mathematical dependencies for predicting the higher calorific value of vegetable raw materials and charcoal based on the carbon and oxygen content and the atomic ratios between carbon and oxygen were developed. A statistical analysis of the relationship between the indicators of technical and elemental analyses, as well as the calorific value of 73 charcoal samples was carried out. The analysis of the studied dependencies has shown that they are generally characterized by satisfactory accuracy, as evidenced by the high values of the correlation and determination coefficients. Based on the data obtained, it can be concluded that the calorific value can be predicted with satisfactory accuracy based on the data on the yield of volatile substances or non-volatile carbon. The coefficient of determination in this case is 0,8002. Key words: vegetable raw materials, biomass, charcoal, elemental composition, quality indicators, calorific value, mathematical dependencies. Corresponding author: Denis Viktorovych Miroshnychenko, e-mail: dvmir79@gmail.com

Вплив сировинних та технологічних факторів на сорбційні властивості доменного коксу.

The influence of raw material factors (component composition of batches, petrographic characteristics, indicators of proximate and plastometric analyses, granulometric composition) and technological factors (coking period, process temperature) on the sorption properties of the carbonized product (coke) has been studied. Based on the research results, it is shown that such characteristics of coke as low humidity and ash, minimal yield of volatile matters, developed pore system and low cost make its use as a sorbent promising and economically justified. Standardized methods for studying the technological properties of coal and coal blends (particle size distribution, technical analysis, petrographic analysis), as well as special methods for determining the sorption capacity (for alkali and acid) and adsorption activity (for iodine and methyl blue) were used in the study. The qualitative characteristics of coke were studied using physical, mechanical and thermochemical methods to investigate standardized indicators: particle size distribution, fractility (M25), abrasion (M10), reactivity (CRI), and post-reaction strength (CSR). Mathematical statistics methods were used to analyze the influence of raw material factors on the characteristics of coke sorbent. The conducted research made it possible to establish the dependence of the sorption characteristics of coke on the structural features and nature of coal raw materials (yield of volatile matters, vitrinite content) and the structure and degree of readiness of coke (yield of volatile matters coke). The obtained dependences for predicting the alkali and acid sorption capacity and iodine adsorption activity, taking into account the vitrinite content and the volatile matter yield of the charge, are characterised by high correlation coefficients r (0.912 and 0.927 and 0.937, respectively), so they can be recommended for predicting these indicators. Keywords: carbon adsorbents, coke sorbent, sorption capacity, adsorption activity, activation. Corresponding author: D.V. Miroshnichenko, e-mail: dvmir79@gmail.com

Comparative Analysis of Thermal Decomposition Kinetics of Copolymers Based on Polyethylene Glycol Fumarate with Methacrylic Acid

The thermal properties of a copolymer based on polyethylene glycol fumarate with methacrylic acid in a nitrogen atmosphere were studied in this paper. Four various heating rates and two types of a polyester resin composition were used. The analysis of thermal decomposition kinetics was implemented. Three kinetics methods namely Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Friedman were applied. Curves of a thermogravimetric analysis demonstrated that the thermal decomposition of copolymers with different molar ratios was observed. It was determined that the kinetic data depends on the studied copolymers’ composition. The obtained data showed a good convergence in various heating rates. Also, the thermodynamic characteristics were calculated namely the changes in the Gibbs energy (ΔG), enthalpy (ΔH) and entropy of activation (ΔS). The Achar-Brindley-Sharp method was used to find the invariant kinetic parameters of decomposition. Thus, the the kinetic compensation effect was applied to define a reaction model and a pre-exponential factor. A main phase of the copolymer decomposition in a narrow temperature range was determined. It was attested by a peak on the differential curve. An insignificant mass loss of the volatile-matter yield was observed in the range of 30–150 °C.

Petrology and organic geochemistry of the Baishaping and Damaidi Devonian cutinitic liptobioliths, west of the Kangdian Uplift, China

Devonian cutinitic liptobiolith is a special type of coal formed during the early evolutionary stage of land plants. The Baishaping and Damaidi Devonian coals are notable for their distinct papery, sheet-like texture, and unusually high cutinite content (>50%), belonging to typical cutinitic liptobiolith. They are bituminous coals and have a suppressed vitrinite reflectance. Compared with typical type III kerogen, these liptobioliths are characterized by extremely high yields of volatile matter and high hydrogen contents owing to their enhanced cutinite contents. As indicated by pyrolysis and elemental analysis results, the Devonian cutinitic liptobioliths are dominated by type I-II kerogens and have an excellent potential to generate liquid hydrocarbons. The Baishaping cutinitic liptobioliths are mainly composed of ribbon-like thick-walled cutinites, with small amounts of thin-walled type. Vitrinite is only present in trace amounts and is dominated by telinite. Meanwhile, the Damaidi Devonian coals are primarily composed of ribbon-like thin-walled cutinites, followed by collotelinites which are usually sandwiched by cutinites. The different petrological characteristics of the Baishaping and Damaidi liptobioliths might indicate a structural variation in the coal-forming plant cuticles and two distinct coal-forming conditions. The molecular biomarkers in the Devonian coals are mainly composed of C 18 –C 20 tetracyclic diterpenoids, which are assumed to be the dominant soluble constituent of the Devonian land-plant cuticles and might have played an important role in early land plant radiation. Other molecules include aromatic tetracyclic diterpenoids, 3–5 ring polycyclic aromatic hydrocarbons and their methylated counterparts, and C 16 - and C 18 -monocarboxylic acids. n -Alkanes are present only in small amounts. The molecular composition of the cutinite-rich coals is unexpected, because cuticular waxes are one of the most important sources of n -alkanes. In general, the petrology and geochemistry of the Devonian cutinitic liptobiolith indicate a distinct structure and composition for the early land-plant cuticles, which is significantly different from that of the plant cuticles since Carboniferous. Devonian cutinitic liptobioliths are of great interest because of their unique petrography, geochemistry, coal-forming plants, and oil-prone potential. Studies on this unique coal type provide a better understanding of coal-forming plants, paleoenvironment, paleoclimate, and early land-plant evolution in the Devonian.

Petroleum coking additive is a raw material for production of metallurgical coke. Part 1. Formation of sintering properties of petroleum coking additive (review)

A significant proportion of the entire mass of waste from the oil refining industry is accounted for heavy sour oil residues, and one of the most common solutions in the world is the recycling of these wastes to obtain petroleum cokes. However, the high sulfur content often does not allow to find a qualified application and a market for the obtained sulfide carbon materials. In this work, a review of the scientific and technical literature on the industrial use of petroleum coking additive (PCA) - petroleum coke with a volatile matter yield of 15 to 25%, as a partial replacement for scarce coking coals in the charge in the metallurgical coke production. As a result of the review and analysis of scientific and technical literature, indicators were established that affect the formation of sintering properties of PCA and the boundary conditions for its use as part of a coal charge. It is shown that the use of petroleum coke with a volatile matter yield of less than 15% (wt.) worsens the quality of the obtained metallurgical coke, reducing its strength characteristics CSR and increasing its reactivity CRI, and the introduction into the coal charge from 5 to 50% (wt.) PCA with a content of volatile substances of 15&ndash;25% (wt.) provides an improvement in the quality of the resulting metallurgical coke. It is noted that, along with an important indicator, as the yield of volatile substances, which affects the formation of sintering properties of PCA, its group chemical composition, determined by solubility in various solvents (&alpha;-, &beta;- and &gamma;-fractions), plays an equally decisive role.The work was carried out within the framework of the State Assignment of the Ministry of&nbsp;Education and Science of the Russian Federation on NIR 0792-2020-0010 "Development of&nbsp;scientific foundations for innovative technologies for processing heavy hydrocarbon raw&nbsp;materials into environmentally friendly motor fuels and new carbon materials with controlled&nbsp;macro- and microstructural organization of the mesophase."

First insights into mineralogy, geochemistry, and isotopic signatures of the Upper Triassic high‑sulfur coals from the Thai Nguyen Coal field, NE Vietnam

This paper represents the first integrated research on the mineralogical, geochemical and stable isotope characteristics of the Upper Triassic high‑sulfur coals from the Khanh Hoa open-pit mine, Thai Nguyen Coalfield, NE Vietnam. Formed in a marine-influenced carbonate succession, the Khanh Hoa coal is characterized by medium ash yield, low volatile matter yield, and high sulfur content. Minerals in the Khanh Hoa coal are predominantly composed of authigenic calcite in the upper portion; and pyrite, quartz, with minor amounts of tobelite ([(NH4), K] (Si, Al)4Al2O10(OH)2), gypsum in the middle and lower portions. The high‑sulfur Khanh Hoa coal is enriched in an As-Mo-Sb-U-Cs-P assemblage, which presents both an organic and inorganic mode of occurrence, and is largely ascribed to hydrothermal fluids. The δ13C values of the Khanh Hoa coal range from −24.77‰ to −22.80‰ (avg. −23.33‰), reflecting a change in sedimentation pattern (from transgressive to high stand system upwards). The δ15N values of the Khanh Hoa coal range from 2.41‰ to 3.73‰ (avg. 3.30‰), possibly resulted from influenced by seawater influence and a redox environment. The mineralogical, geochemical and isotopic characteristics reflected that the high‑sulfur Khanh Hoa coal was formed/preserved in marine-influenced anoxic environment, with low detrital input, and strong activities of multi-stage hydrothermal solutions.

Facies development of coal seams in the Knurów deposit (Upper Silesia, Poland)

This paper presents the first attempt to develop the facies model of the entire coal deposit belonging to the Carboniferous productive sequence located in the western part of the Upper Silesian Coal Basin. To achieve this objective, six seams from the Knurów deposit were examined. The deposit belongs to the largest producer of coking coal in Europe, which is Jastrzębska Spółka Węglowa SA (Polish state-run coking coal producer). The maceral composition, vitrinite reflectance, ash yield content, moisture content, gross calorific value, and volatile matter yield were determined. Coals from the Knurów deposit are classified as ortho-bituminous and meta-bituminous coals. Their average degree of coalification, determined by vitrinite reflectance, is RO = 0.79% to RO = 1.09%. Petrographic indices and the analysis of facies diagrams were used to develop the facies model. It was shown that the facies development and sedimentological evolution of the Knurów deposit were determined by the river system extended to the upper delta plain. In accordance with the stratigraphic succession, the oldest deposits are dominated by the reed facies (mainly Calamites) growing in oxbow lakes and dry streambeds. With the passage of time, the importance of the river system for the development of the paleo-environment decreased. Transitional bogs with mixed plant communities were formed. This started the conversion of wetlands into areas occupied by wet forest. At the end of the sedimentation of the documented coal seams in the Knurów deposit, lowland bogs (fens), which were subject to frequent fires, dominated the landscape. Based on a detailed maceral analysis and facies diagram analysis, a strong correlation between fault occurrence and coal facies developed under paleo-river influence was displayed. The aim of the study is to show environmental changes during deposit formation in the context of geological exploration.

In depth thermokinetic investigation on Co-pyrolysis of low-rank coal and algae consortium blends over CeO2 loaded hydrotalcite (MgNiAl) catalyst

This study investigates the co-pyrolysis behavior of bituminous coal (100%BC), algae consortium (100%AC), and their blends at various blending ratios. The pure and coal-biomass blends were characterized using CHN-S, GCV, and FTIR analysis. Whereas, the co-pyrolysis of blends were performed in a TGA. The deviation between the experimental and calculated values of weight loss (WL%), the residue left (RL%), and the maximum rate of weight loss (wt%/min) was used to calculate the synergistic effects. Kinetic parameters were investigated using the Coats-Redfern integral method through eighteen (18) reaction mechanistic models. The activation energy (Ea) for 100%BC was 85.04 kJ/mol through the F3 model, whilst for 100%AC showed 78.22 kJ/mol using the D3 model. Thermodynamic parameters such as Enthalpy (∆H) and Gibbs free energy (∆G) showed positive values, while Entropy (∆S) was negative for each coal-biomass blend. The catalytic co-pyrolysis of the optimum blend (20BCE-80AC) was studied using CeO2 loaded MgNiAl (CeO2 @MNA) as a multifunctional catalyst. The increased WL% displayed a positive effect toward a higher yield of volatile matter. Ea of the optimum blend in co-pyrolysis was further reduced through catalytic co-pyrolysis and Ea in the first and second stages was 72.48 kJ/mol and 13.76 kJ/mol, while 3 wt% catalyst loading further reduced its Ea in both stages to 67.82 kJ/mol and 41.21 kJ/mol. The use of CeO2 @MNA at 3 wt% loading showed a reduction in the peak devolatilization temperature (Tp) of the optimum blend substantially increasing the reaction rate, and reducing the Ea required for the decomposition process.

Determination of the Composite Panel Moulding Pressure Value.

Currently, prefabricated panel structures are typical products made of polymeric composite materials. The integrity of the composite panels, their structure and accuracy of making a contour are largely associated with the manifestation of residual technological stresses. The above phenomena and associated stress-strain behaviour inevitably occur in the process of moulding of the composite products. However, their value, nature, time of occurrence and dynamics of growth can be fully controlled and regulated. The paper deals with the study of the effect of moulding pressure on the quality of a composite product. A dependence is presented that allows us to determine the time for the degassing of the polymeric composite material package at the given temperature and pressure to obtain a monolithic and nonporous structure. It is shown that the peak of the maximum volatile-matter yield for the considered binder types lies in the temperature range where the degree of curing does not exceed 10%; that is, the viscosity values do not prevent the removal of volatile fractions. The effect of moulding pressure on the values of the volume content of the reinforcing material has been studied, and the dependence of the required thickness of the absorbent layer on the parameters of the package of polymer composite material and pressure has been obtained. The dependence of the required thickness of absorbent layer on the parameters of the package of polymeric composite material and pressure has been obtained. The mathematical model developed by us provides an opportunity to predict the stress-strain behaviour of a composite structure at any time during the moulding process. The model is closely related to chemo-viscous and thermal models. It allowed us to synthetize a method for choosing the rational parameters of the moulding process (temperature, pressure, and time), materials of additional layers and equipment. The experiments proved the presence of several defects, such as de-lamination of edges, waviness, swelling and poor adhesion of upper layers in the specimen of the composite panel cooled stepwise in the absence of the vacuum pressure. The surface quality of the specimen of the panel cooled stepwise under vacuum pressure was significantly better, and no visible defects were observed. The obtained theoretical values of deflections, considering the change in physic-mechanical characteristics that depend on the temperature and rheonomic properties of the material, showed an error that did not exceed 7%, compared to the experimental data. Our results can be applied at the enterprises engaged in designing and manufacturing panel structures of polymeric composite materials.