Lignite Research Articles

Low Grade Coal Quality With Up Graded Brown Coal Technology

The aim of this research is to increase the calorific value of coal. In this way, coal which has a calorific value of 3500 kCal/kg can be increased to 6500-7000 kCal/kg. Apart from that, by carrying out this up grading, a number of volatile meters will disappear as a result of the heating and pressure process. The knock-on impact is an increase in the economic value of coal and thus the selling price will be more competitive. After the data was collected, the data was analyzed using descriptive methods. The descriptive method is used to describe the upgraded brown coal (UBC) process. Findings that can be obtained in this research include: 1) Potential company profits can be increased, 2) Increased local government income through taxes, 3) Many mining areas can be exploited, 4) Reduction of unemployment by expanding employment opportunities in the mining sector, 5) Reducing environmental damage by mining power by mining wisely. 6) Reducing environmental pollution due to the combustion process. 7) With this process, investment in the coal mining sector can be increased. This research concludes that the economic value of low quality coal will increase and the profits that can be obtained will be better.

Method of hydrothermal treatment for coal spontaneous combustion inhibition and its application

The use of coal combustion inhibitors, which are mostly sprayed on the surface of the coal that remains in the mining region (post-mining inhibition), has a significant effect on preventing spontaneous burning of coal, although their duration of action is limited. Pre-inhibition (pre-mining inhibition) prolong the inhibition duration and offers the chance to change the temperature of the inhibition fluid. This results in the suggestion of a hydrothermal inhibition strategy that emphasises the influence of inhibition fluid temperature on the inhibitory effect in order to achieve accelerated inhibition. Infrared tests and temperature-programmed oxidation are used to explore the inhibition law and mechanism of inhibition temperature on the spontaneous combustion of different coal orders. The findings demonstrated that when the inhibition temperature increased to 30 °C, 40 °C, 50 °C, 60 °C and 70 °C, the average inhibition rate and cross point temperature increased dramatically while the rates of oxygen consumption, exothermic rate, and CO production continuously dropped. Simultaneously, the coal's content of more reactive groups, such methyl and methylene, dropped, and the coal's risk to self-heat reduced. At the 70 °C inhibition temperature, the lignite coal showed the maximum inhibition rate (65.28%). This research is crucial to advancing the inhibitor's application technology and efficiency of inhibition.

Assessment of Ovbiomu Coal for Industrial Application

This research is to assess the quality of Ovbiomu lignite coal deposited for optimum utilization in metallurgical industries in Ovbiomu. Samples of coal were collected for analysis and sample was collected from five different stationary lots until 10 kilograms of the sample was collected and 500g was taken for characterization. The sample was reduced using jaw crusher and ball milled to a size of 1400μm and 1 kilograms of 1400μm was further reduced to 1100μm and was classified into various sieve sizes using mechanical sieve shaker. CalK2 bomb calorimeter was used to determine the calorific value of the head sample, the economic liberation size and the actual liberation size. The proximate analysis of the head sample and all the sieve sizes was done using Furnace, oven, porcelain crucibles, analytical balance, and desiccator to ascertain the individual carbon content. Ultimate analysis was done using XRD and concentration was done using froth flotation method. Result from sieve analysis shows that at 1000 μm, 710 μm, 500 μm, 355 μm, 250 μm, 180 μm, 25 μm, 90 μm, 63 μm, and -63 μm, the following weight was retained 1.45 g 1.86 g, 3.73 g, 3.5 g, 14.61 g, 48.28 g, 0.15 g, 0.17 g and 0.20 g respectively. The economic liberation size was found out to be 180um where most of the sample is retained and the actual liberation size was found out to be 125um but with a very small quantity retained. The results of the calorific value of the head sample and each of the sieve sizes of 250μm, 180μm, and 125μm, was determined to be 24.51MJ/Kg, 25.86MJ/Kj, 18.57MJ/Kg and 38.07MJ/Kg respectively, the following are result of percentage carbon content, for the Head sample (40.65%), 1000μm (29.55%), 710μm (38.53%), 500μm (42.43%), 335μm (35.42%), 250μm(43.07%), 180μm (30.92),125μm (63.40%) 90μm (0.56%) 63μm (0.62%) and -63μm (9.91%). The result of ultimate analysis of the sample shows Nitrogen (1.15%), Hydrogen (4.80%), Sulphur (0.13%) and Oxygen (29.56%).

Trends in the Growth of Damage Extents in a Steel Conveyor Belt’s Core

The initial set of four measurements (scans) captures the failures occurring in the core of steel cable conveyor belt segments used in a lignite coal mine in Poland. These measurements utilize the DiagBelt+ magnetic system, enabling the analysis of averaged damage sizes. The scanning results allowed the analysis of complete changes in the failure sizes to a maximum of six different time intervals from 1 to 19 months. The cumulative increase in the length and width of the failure (their total extent in both directions) is a linear function of time. However, the inclination of the selected lines (growth speed) depends on the age of the belt segment at the time of its first scan. It is possible to find the best regression function of slope coefficients for the age of the belt segment. The obtained results are crucial for rational belt management, including reliable short-term forecasts of belt needs with the flow of time, indications of the best moments for belt segment replacements, and estimating the budget of the belting department.

The use of petroleum derivative mixtures as bridging liquid for oil agglomeration of lignite coal

ABSTRACT The aim of the present study was to investigate the use of mixtures of petroleum derivatives as bridging liquids for oil agglomeration of Sivas/Gemerek lignite coal. The study investigated the effect of various physical process parameters, such as type and dosage of bridging liquid, pulp pH, pulp density, agglomeration time, and coal particle size. Oil agglomeration experiments were evaluated along with yield, organic matter recovery and ash rejection values. The optimum conditions for agglomeration were found as follows: adding engine oil (0w-30) as a bridging liquid at a dosage of 30%, maintaining a pulp pH of 2, using a pulp density of 3.6% w/w, agglomerating for 25 minutes, and using coal particles with a size of −500 µm. Under these optimum oil agglomeration conditions, a yield of 85.4%, an organic matter recovery of 94.1% and an ash rejection of 51.6% were obtained. Under the optimum oil agglomeration conditions achieved, the ash content of the Sivas/Gemerek lignite coal was reduced from 19.1% to 15.5% level.

Rare Elements and Nonferrous Metals in Paleogene Brown Coal Deposits of the Zeya–Bureya Sedimentary Basin (Amur Region, Far East): Accumulation Models, Enrichment Conditions, and Criteria for Assessment of Resource Potential (A Review)

Rare Elements and Nonferrous Metals in Paleogene Brown Coal Deposits of the Zeya–Bureya Sedimentary Basin (Amur Region, Far East): Accumulation Models, Enrichment Conditions, and Criteria for Assessment of Resource Potential (A Review)

Complex microwave processing of high-ash brown coal in relation to the energy and metallurgical industries

Relevance. The need of the Tomsk region for valuable energy resources obtained from local low-grade resources to develop iron ore deposits available in the region and cover energy needs. Aim. To study gaseous and solid products obtained from low-grade brown coal of the Talovsky deposit (Tomsk region) under microwave pyrolysis conditions in relation to the energy and metallurgical industries. Objects. Brown coal of the Talovsky deposit (Tomsk region). Methods. Certified SS methods to determine thermal characteristics and elemental composition of coal organic and mineral parts, the "transmission-reflection" method for measuring imaginary (ε'') and real (ε') components of the complex dielectric permittivity, physical experiment, gas analysis, Brunauer–Emmett–Teller method for measuring texture characteristics. Results. Brown coal of the Talovsky deposit has high values of moisture and ash contents for operating conditions, which leads to a low calorific value. Such characteristics make it possible to classify coal as a low-grade fuel, which indicates the inexpediency of its use as a raw material for the energy and metallurgical industries. Thermal processing by means of microwave pyrolysis makes it possible to obtain a high-calorie (heat of combustion over 21 MJ/m3) and environmentally friendly (hydrogen content over 29%) gaseous fuel from the low-grade brown coal of the Talovsky deposit. The resulting solid carbonaceous residue has an ash content of over 48%, which required its chemical treatment in a solution of HF and HCl. As a result of the solid carbonaceous residue treatment, its ash content decreased by more than 38%, the sulfur content – by more than 1.5 times. According to its characteristics, the resulting product corresponds to the currently available carbonaceous products – semi-coke, coke and carbon reducing agent for ferroalloy production.

Ignition behavior of a mixture of brown coal and biomass during the movement of fine particles in a hot air flow

The combustion of brown coal, biomass and their mixtures was studied experimentally and analytically. The experimental research was conducted using a laboratory setup that reproduced the conditions of combustion of pulverized solid fuel in a boiler furnace. Thermogravimetric analysis was employed as part of the analytical study to determine the key characteristics of combustion of solid fuels, such as temperatures at which the ignition and burnout occur, as well as the combustion index. Scanning electron microscopy was utilized to analyze the surfaces of coal and wood particles to detect pores, cracks and channels. To determine the tendency of the solid fuel mixture to slag heat exchangers in boiler furnaces, the ash residue characteristics (iron oxide deposits, active alkali, calcium sulfate compounds) were obtained. Biomass is more reactive than brown coal. Its ignition delay times at 500 °C and 750 °C are 57 % and 25 % lower, respectively, than those for coal. The higher the biomass content in the solid fuel mixture, the lower the ignition delay time. The heating source temperature at which the coal/biomass fuel mixture ignites corresponds to the temperature at which biomass ignites. With a larger proportion of biomass, the temperature during the fuel mixture combustion goes down, while the combustion index increases. On the basis of the findings of the conducted research, optimal proportions of solid fuel components were found (80 % brown coal, 20 % biomass). Also, fuel preparation and feeding systems for pulverized fuel combustion and fluidized bed combustion of optimal fuel mixtures in a coal-fired boiler furnace were proposed.

Pyrolysis characteristics and product distribution of low-rank coal with heat-carrying particles adopting TG-FTIR and a novel self-mixing down tube reactor

A novel self-mixing down tube (SDT) pyrolyzer has been developed, which can separate the heat carrying particles preheated in the fluidized bed from the coal, and the two can be mixed through a specific structure to instantly heat the coal particles to a predetermined temperature. The present study investigated the pyrolysis behavior of low-rank coal with hot silica sand heat-carrying particles adopting TG-FTIR. Identifies optimal conditions for maximum tar production in a laboratory-scale SDT using a significantly larger range of coal feed rates (4 kg/h). An increase in the degree of coal metamorphism increased the initial temperature and the yield of char. The tar yield from Huolinhe lignite coal (6.56 %) and Daliuta bituminous coal (7.48 %) showing a trend of first increased and then decreased with elevating the operating temperature and optimal temperature at 520 °C, respectively. The effect of coal particle size on tar yield mainly comes from the different degrees of secondary cracking caused by contact with solid heat-carrying particles as well as the differences in the content of macerals. GC‒MS spectra of tar and deposited carbon on silica sand indicated that heavy tar can easily deposit on the surface of sand and form char through polymerization reactions.

Synergistic production of fuels from co-pyrolysis of lignite coal and waste plastic

In this study, the co-pyrolysis of Thar lignite coal and waste plastic was investigated, exploring the effects of different parameters such as the coal to waste plastic blending ratio and temperature. The oil obtained from pyrolysis was analyzed for GCV, viscosity, flash point and for chemical composition through GC-MS and FTIR techniques. The results revealed that a blend of 20 % coal and 80 % waste plastic yielded 67 % pyrolysis oil with a GCV of 42 MJ/kg. It was found that adding waste plastics to coal enhanced both the yield and quality of pyrolysis oil. Physical parameters including viscosity and GCV were found to be highly promising and comparable to regular Petro diesel. According to FTIR, presence of significant quantities of aliphatic and aromatic linkages along with carbonyl and hydroxyl functional groups were observed. Similarly, GCMS analysis showed the presence of C7 to C20 carbon fractions in pyro-oil of optimum sample. Char residue 21 % was also obtained from the results with carbon contents up to 68 % and less than 1 % sulfur at 80:20 blending ratio of WP and coal. This char residue could be especially useful for use in steam generation or cement industries as clean fuel.

Mechanical Activation as a Stage of Coal Sample Preparation in the Analysis of Rare Earth Elements Content by Inductively Coupled Plasma Mass Spectrometry

Background: Brown coals are recognized as promising sources of rare earth elements (REEs). Rare earths are present in both the mineral and organic parts of brown coal. Objectives: This study was conducted to investigate the influence of preliminary mechanical activation in the process of sample preparation prior to analyzing the concentrations of rare earth elements in brown coal samples of various origins and compositions Methods: Four coal samples from different deposits in Russia were selected for the study. Samples were treated with mechanical activation, without reagents, or mechanochemical activation, with humic acids added externally as reagents. X-ray phase analysis was carried out with the selected samples. The quantities of rare-earth elements present in the samples were studied by the method of high-sensitivity inductively coupled plasma mass spectrometry (ICP-MS). Results: It was found that the mechanical activation of coal before dissolution in a mixture of nitric and hydrofluoric acids leads to an increase in the determined concentration of rare earth elements. For this study, the expediency of using only nitric acid as an optimal solvent for the elemental analysis of coal samples was shown. The total concentration of all REE after dissolution of nitric acid and mechanochemical activation with humic acid reached 2456 g/t in Vanchin coal, 968 g/t in Azeysky coal, and 24 g/t and 150 g/t in Itatsky and Spetsugli coals, respectively. Conclusion: Mechanical activation and mechanochemical treatment can greatly help to facilitate sample preparation of natural objects, such as coals for elemental analysis, but in some cases, only a change of solvent is sufficient. When developing technology for concentrating rare earth elements from coal involving grinding, it is necessary to take into account the fact that mechanical activation of coal changes its tendency to dissolve, which may affect the results of the analysis and should be taken into account during experiments.

Energy and Exergy Analyses of Supercritical Coal‐Fired Power Plant With Single Reheat and Regenerative

This paper investigates energy and exergy analyses of 660 MW capacity supercritical coal power plant with single reheat and regenerative. The fuel utilized in the plant is a combination of sub‐bituminous and lignite coal. It is found that the turbine section of the system exhibits the highest energy efficiency (around 94.17%) and exergy efficiency (around 90.73%). Also, 82.07% of the total exergy destruction is found for the boiler, and the remaining 17.93% of the irreversibility is determined for the turbine, condenser, and other components. The overall cycle energy efficiency at maximum load is computed as 40.77%, while the overall cycle exergy efficiency at maximum load is found to be 39.69%. These findings provide valuable insights into the performance of the power plant and suggest the improvements needed in performance enhancement of the boiler.

Dynamics of sulfur absorption by marble during combustion of layered brown coal charge

The change of the elemental composition of a layered charge consisting of particles of sulfur brown coal and marble during oxidation in a furnace heated to 1200°C has been studied. It has been determined that as coal burns out, the sulfur was released into the gas phase and partially absorbed by marble. At the final oxidation temperature (1200°C), approximately 5% of the initial sulfur content remains in the coal, about 40% was absorbed by the marble, and the remaining 55% passes into the gas phase.

THE SOCIAL COST OF CARBON EVALUATION BASED ON CARBON CAPTURE AND STORAGE TECHNOLOGIES FOR POWER GENERATION PLANTS

Power plants produce electricity using high amounts of fossil fuels such as coal. Using these fossil fuels releases very high emissions into the atmosphere. Carbon capture and storage (CCS) applications have been developed to reduce these emissions. Thus, by capturing 96% of the CO<sub>2</sub> formed from the burning of fuels in power plants, the global warming potentials emitted by conventional electricity generation can be reduced by up to 80%. The study investigated applications of CCS options to reduce emissions during electricity generation, CO<sub>2</sub> emissions, pre-combustion, post-combustion, and oxyfuel coupled global warming potentials. The reCiPe midpoint method has been taken into account for CO<sub>2</sub> emission. CCS options calculate the reduction in global warming potential. The study accepts that hard and brown coal is used as fuel in power plants that produce electricity. Finally, for the three cities with the highest electricity consumption in Turkey, the global warming potential emission in conventional electricity generation power plants burning brown coal is calculated as 43.4 kilotons for plants burning brown coal. It has been calculated as 6.2 kilotons in power plants using oxyfuel CCS and burning hard coal. Ten-year life for Istanbul, for hard coal burning and pre-combustion related discount rate of 1% and 3 $/ton social cost of carbon; The social cost of carbon is calculated as $102.8 million.

О ВЗАИМОЗАВИСИМОСТИ РАЗВИТИЯ ОРГАНИЧЕСКОГО СЕЛЬСКОГО ХОЗЯЙСТВА И ПРОМЫШЛЕННОГО ПРОИЗВОДСТВА ГУМИНОВЫХ УДОБРЕНИЙ

. In accordance with the Federal Law “On Organic Products and on Amendments to Certain Legislative Acts of the Russian Federation” No. 280-FZ dated August 3, 2018, Government Order No. 1788-r dated July 4, 2023 the Strategy for the Production of Organic Products until 2030 is approved. The Russian Ministry of Agriculture has been instructed to develop a road map for its implementation. The analysis of the main activities of the Strategy shows how the work of an agricultural producer should be structured in preparing the appropriate documentation for the organic products he produces. At the same time, in the Strategy there is not enough analysis and measures on the basis of which the material and technological base of agricultural organizations should be built. There is no definition of the concept of soil, soil fertility, to improve the crop rotation system based on the preservation of soil fertility with the use of long-acting organic fertilizers obtained from organic raw materials and the development of industrial capacities for its processing. The use of livestock and poultry waste for these purposes in accordance with the Federal Law of July 14, 2022 No. 248-FZ “On Livestock By-Products and on Amendments to Certain Legislative Acts of the Russian Federation”, which comes into force on March 1, 2023, allows for the creation of additional conditions for production of organic fertilizers. However, the projected volumes of demand for these fertilizers due to the sharp reduction in the cattle herd can be met by 35–40 %. A solution to this problem is possible by organizing the industrial production of organic fertilizers from peat and brown coal, the reserves of which in Russia are sufficient for these purposes

Техніко-економічна оцінка різних способів газифікації бурого вугілля для виробництва синтетичного моторного палива

The aim of the article is to assess the feasibility of organizing the production of synthesis gas from brown coal, the reserves of which in Ukraine are sufficient. As a raw material base, the article considers the coal of the Novo-Dmytrivske deposit, which is located on the territory of the Kharkiv region. The balance reserves of brown coal in categories A + B amount to 284.4 million tons and in category C1 – to 95.6 million tons, that is, a total of 380 million tons. The average technical analysis data for the deposit are as follows: moisture per working weight is 51.2%; ash content per dry weight is 19.4%; the total sulfur content is 2.45%. The elemental composition of the coal of this deposit is characterized by the following data: carbon – 68.0%, hydrogen – 6.0%, oxygen – 23.0%, sulfur, nitrogen and other elements – 3.0%. To achieve the goal, the properties of coal of this deposit have been examined and the following technologies of coal gasification have been analyzed: Lurgi process (counter-current steam-oxygen gasification of coarse coal (or briquettes) in a stationary bed); Prenflo process (direct-flow steam-oxygen gasification in a pulverized coal stream); Texaco process (direct-flow oxygen gasification in a coal-water pulp stream). For each of these processes, material balances have been developed; the quality of gas synthesis, the possibility of organizing the production of the necessary energy resources, the level of emissions of harmful substances into the atmosphere, and the main technical and economic indicators have been evaluated. The calculations were made for an enterprise with a coal capacity of 9 million tons of actual weight per year. Based on the calculations made, the Lurgi process is recommended for industrial implementation. The advantages of this process are: the lowest temperature and pressure of the gasification process; a wider range of products obtained during gasification; almost optimal syngas composition in terms of H2 : CO ratio; the lowest emissions of carbon dioxide generated during coal gasification and preparation of synthesis gas for further use; the lowest production cost of prepared synthesis gas; the lowest specific capital investments (per 1 thousand m3 of prepared synthesis gas). The inexpediency of using the Texaco process for the gasification of brown coal is substantiated, as well as the directions for improving the Prenflo process for its further use in the gasification of brown coal of the Novo-Dmytrivske deposit are determined.

Production of humic and fulvic acid analogs through the ultrasonication of low-rank lignite coals

We present a process utilizing an ultrasonic horn-type reactor for the conversion of lignite-coal into humic and fulvic acid analogs, achieving a 72% yield of humic acid analogs and 92% conversion.

Simulation model of 177 MWe coal-fired double power unit

Model-based studies are widely used in the analysis and optimization of complex energy conversion processes in large thermal power plants. The creation and validation of a model of a power unit utilizing Bulgarian lignite enables us to study in detail the redistribution of heat flows in that unit. Along with the ability to optimize the thermodynamic cycle of energy generation, this research method enables us to conduct many study tasks that cannot be realized by conducting expensive and complex industrial experiments. The current article presents the creation of thermodynamic simulation model of a 4th power unit firing lignite coal in Maritsa East 2 TPP. Validation of the numerical solution was performed with data from the "Operating Instructions for the boilers”, design heat balance calculations for steam turbine installation and performance test results onsite on two different loads.

Assessment of the sequestration strategy based on brown coal Shoptykol to reduce organochlorine pesticides transfer from contaminated soil to hen eggs

This study investigated the efficiency of a sequestration strategy using carbon-based materials to reduce the transfer of organochlorine pesticides (OCPs) from hens to eggs. Specifically, the potential of Kazakhstan-made Shoptykol coal was evaluated by applying 2% (by weight) of this material to OCP-contaminated soil obtained from Kyzylkairat (Almaty region, Kazakhstan). The experiment was conducted by exposure for 45 days of 18 hens, which were divided into three groups depending on their feeding conditions. Laying hens were fed diets containing 10% of soil: for the first group with control soil A, the second group with contaminated soil K, the third group with contaminated soil containing coal. Quantification of pesticide concentrations in egg yolks of laying hens was then performed by gas chromatography mass-spectrometry. Despite the supply of Shoptykol, no significant reduction in OCPs transfer was observed for compounds tested. Thus, the efficiency of Shoptykol coal in reducing the transfer of organochlorine pesticides to animals was not confirmed by our results.

On the Possibility of Waste-Free Use of Mineral Resources of the Angrensky Brain Coal Deposit

The Angren lignite basin is a complex coal-kaolin deposit. Here, in addition to brown coal, there are large reserves of kaolin clays of two types - primary and secondary, occurring respectively in the soil and the roof of the coal strata. Secondary clays, in turn, subdivided into gray and variegated, which during overburden and mining of coal seams in the bulk go to the dump. Gray kaolins currently partially processed at the “Angren Kaolin” LLC factory in order to obtain enriched kaolin used for the production of building ceramics, etc.