Types Of Lignite Research Articles

Assessing the Rainfall Implications on Surface Coal Mining Operations: Thar Case Study

Rainfall directly impacts the open-pit surface mining operations in the Thar Coalfield, Pakistan. The overall lithology hosting the lignite type of coal seams in the study area includes Dune Sand, alluvium, and soft sedimentary rocks. Due to the presence of three primary aquifers, the strata overlying and underlying the coal seams are under substantial porewater pressure. Additionally, heavy rainfalls in the Thar area lead to the accumulation of water in mines and may cause pit flooding, making it impossible to continue mining activities until the water is pumped out. Pit flooding often results in equipment damage and production delays. The main focus of the study is to investigate the impacts of heavy rainfall on the mining activities at Thar Coalfield. Two major aspects of open pit mining are considered in this study, i.e., production, and dewatering systems. Due to heavy rainfall, a significant production deviation (V) was noticed in comparison to regular months. The quantity of water drained from the pit (Qa) and anticipated inflow quantity (Qt) values were compared for the rainy season and other times. It was observed that heavy rainfall increases the production deviation from the planned targets and also increases the pit dewatering cost. Moreover, this study suggests preventive measures to address potential losses arising from intense rainfall.

Combustion characteristics of low-quality lignite for different bed material sphericities in a circulating fluidized bed boiler: A numerical study

This study delves into the combustion behavior of various lignite types within a circulating fluidized bed boiler (CFBB), with a primary focus on the impact of different bed material sphericity ratios (0.5, 0.7, and 0.9). Utilizing bed material with a sphericity ratio of 0.9 sourced from the Çan power plant and verified through experimentation, the research reveals several key findings. Notably, furnace temperatures tended to rise with higher sphericity ratios, albeit with variations between lignite types, particularly highlighting the complexity of this relationship in the case of GLI-Tunçbilek lignite. Pressure levels in the combustion chamber remained consistent across different sphericity ratios, indicating minimal influence on pressure dynamics. Improved combustion efficiency, especially at the bottom of the boiler, was observed at lower sphericity levels (0.5 and 0.7) for Çan lignite, as reflected in CO2 mole fractions. While NOx emissions generally decreased with lower sphericity, the sensitivity to sphericity varied by lignite type, with Ilgın lignite showcasing low NOx but high SO2 emissions, underscoring the intricate interplay between lignite properties, sphericity, and emissions. Overall, this study advances our understanding of CFBB combustion dynamics, offering insights valuable for optimizing performance and emissions control, particularly in lignite-based power.

Analysis of influencing factors in permittivity of oxidized lignite by FTIR, XRD, and THz-TDS based on orthogonal experiment

As an organic-rich and mineral-rich mixture, the permittivity of oxidized lignite is dependent on several factors in the terahertz (THz) band. In this study, thermogravimetric experiments were conducted to determine the characteristic temperatures of three types of lignite. The microstructural characteristics of lignite after treatment at 150, 300, and 450 °C were investigated by Fourier transform infrared spectroscopy and X-ray diffraction. The results show that the changes in the relative contents of CO and SiO are contrary to those of OH and CH3/CH2 with temperature variation. The relative content of CO is unpredictable at 300 °C. The aromaticity and crystallite diameter show a regular variation with temperature. The microcrystalline structure of coal tends to undergo graphitization with temperature. The variation of crystallite height is random at 450 °C. The uniform variation in microstructural characteristics of different types of lignite with oxidation temperature proves the feasibility of identifying oxidized lignite by THz spectroscopy. Based on orthogonal experiment results, the influence of the coal type, particle diameter, oxidation temperature, and moisture content on the permittivity of oxidized lignite in the THz band was arranged in an order. The order of the factors’ sensitivity for real part of permittivity is oxidation temperature > moisture content > coal type > particle diameter. Similarly, the order of the factors’ sensitivity for imaginary part of permittivity is oxidation temperature > moisture content > particle diameter > coal type. The results reveal the capability of THz technology to characterize the microstructure of oxidized lignite and provide guidance for minimizing error in THz technology.

Дослідження хімічно-фізичних особливостей похідних бурого вугілля для оцінки потенціалу їх гібридної функціональності

STUDY OF CHEMICAL AND PHYSICAL FEATURES OF LIGNITE DERIVATIVES FOR EVALUATION OF THEIR HYBRID FUNCTIONALITY POTENTIAL © V.V. Lebedev, PhD in technical sciences, D.V. Miroshnichenko, Doctor of Technical Sciences, D.O. Savchenko, E.I. Lytvynenko, PhD in technical sciences (National Technical University «Kharkiv Polytechnic Institute», 2 Kyrpychova Str., Kharkiv, 61002, Ukraine)) The article shows that despite the existence of studies on the modification of various types of polymeric materials with lignite and its derivatives (in particular, it has been proven that the addition of lignite to polymers can affect their biodegradation), there is a further need to study the physicochemical features of the hybrid functionality of these materials in relation to a wide range of materials. The paper analyzes lignite and its derivatives in the form of humic acids in terms of their use for hybrid modification of multifunctional materials. The subject of the study is related to the non-energy and non-fuel use of fossil coal. This area is one of the most promising, as it allows to obtain marketable products of high demand, the cost of which is much higher than the cost of the raw materials. By performing qualitative, quantitative, and spectroscopic analyses of humic acids of different types of lignite, it has been proved that they have a significant hybrid functionality due to the presence of a large number of different functional groups in their composition. It has been shown that the most characteristic functional groups of lignite humic acids include phenolic hydroxyl -OH groups, carboxyl COO-, NH2 deformation groups, aliphatic CO groups, etc. This determines the ability of lignite humic acids to act as hybrid modifiers in relation to a wide range of substances through the following mechanisms: chemical interaction, dipole-dipole interaction in the form of hydrogen bond systems, and configuration changes in the structure of various materials and substances. It has also been found that the high hybrid functionality of lignite humic acids is determined by their polarity, which significantly increases the reactivity of active peripheral groups. Keywords: coal, humic acids, hybrid functionality, modification, properties. Corresponding author Denys V. Miroshnychenko, e-mail: dvmir79@gmail.com

Pollutants release from the residues remaining after underground gasification (UCG) of ortho- and meta-lignites

One of the most significant environmental risks related to underground coal gasification (UCG) is groundwater contamination, which could potentially occur after process shutdown. This work comprises the results of laboratory tests on characteristics of UCG solid residues which were produced in the ex situ underground gasification of ortho- and meta-lignites and which may be a potential source of pollutants release to the surrounding area. Two multi-day trials were carried out in a large scale UCG ex situ reactors. The gasification tests were conducted in an artificial coal seam in the atmospheric pressure system. Two different types of lignite were gasified, i.e. meta-lignite from Velenje Coal Mine (Slovenia) and ortho-lignite from Oltenia Coal Mine (Romania). The aim of this study was to examine whether the type of lignite has an influence on the composition of the post-gasification residues, including contaminants that can be leached to the surrounding aquatic environment from the cavity formed as a results of UCG. The solid post-process residue samples obtained from different sections of the reactor were characterized and the leaching behaviour of some organic and inorganic parameters present in post-process residue was investigated. Additionally, the partitioning of metals and metalloids during underground gasification of two types of lignites (ortho- and meta-lignite) was discussed. The effect on lignite properties on the behaviour of metals and metalloids in the process of gasification and leaching to the water phase was also confirmed in the study. Leaching tests have been performed in terms of evaluation the capability for inorganic and general organic compounds elution from post-process residues after UCG of lignites. The study shows that samples originating from various parts of the UCG reactor differ strongly and may release contaminants to the vicinity of the georeactor. However, no dangerous trace elements such as Cr, Cd, Hg and Pb occurred in the aqueous extracts, which may indicate that in the post-operational phase, the UCG of lignite is a process safe for the aquatic environment.

Effect of lignite amendment on carbon and nitrogen mineralization from raw and composted manure during incubation with soil

The application of animal manure as a source of plant nutrients requires the determination of the amount and pattern of nutrient mineralization from manure. A laboratory incubation study was conducted to investigate the influence of lignite amendment and lignite type on carbon (C) and nitrogen (N) mineralization in raw (feedstock) and composted cattle manure following application to soil at 30 and 60 t ha -1 . The mineralization of C and N was determined by measuring changes in CO 2 evolution and mineral N (NH 4 + -N + NO 3 - -N) over 40 d. The results showed that lignite amendment suppressed the amount of manure C mineralized in both feedstock and compost, with the effect being more pronounced in the compost. Over the 40-d incubation, the percentage of applied C mineralized was 26.4%–27.8% and 16.3%–21.4% in unamended and lignite-amended feedstocks, respectively. The corresponding C mineralized in the composts was 12.4%–14.1% and 3.5%–6.5%. Lignite had no significant effect on the net N mineralized in compost (4.8%–6.7% and 2.5%–7.8% in unamended and lignite-amended composts, respectively). Lignite had either no effect or increased the net N mineralized in feedstock (from 3.2%–8.7% without lignite to 10.4%–13.5%) depending on the type of lignite used. This study suggests that using lignite-amended manure, especially when composted, has the potential to build up soil organic C without limiting the availability of mineral N.

Assessment of the moisture storage characteristics of lignite focusing on lignite type, moisture forms and drying mechanism

ABSTRACT To further study the occurrence form of moisture in coal, better understand the dehydration mechanism and the interaction between water and coal structure, as well as improve the utilization rate of lignite, non-isothermal and isothermal dehydration experiments were carried out on Zhaotong, Yimin and Zhundong coal samples under different initial conditions. The results showed that the dehydration rate of lignite is related to the temperature and initial water content. The effective moisture diffusion coefficient rises with an increase in temperature and water content. This indicated that the higher the temperature, the easier it is for water removal. In the isothermal dehydration experiment, the activation energy decreases with the increase of water content, indicating that the coal sample with large water content is easier to dehydrate, whilst the opposite result was obtained in non-isothermal dehydration experiment. According to the different drying mechanisms and characteristics at different stages, the total water content of lignite can be divided into four parts: chemical bound water, transitional bound water, physically bound water and free water. The removal mechanism and influencing factors of each have been analyzed in depth. The removal difficulty and required energy consumption is found to be successively reduced.

Improved Lignite Predrying System Integrated with Heat and Water Recovery from Wet Flue Gas at Lignite-Fired Power Plants: Energy and Water Conservation

To improve energy efficiency and reduce water consumption simultaneously in lignite-fired power plants, an improved lignite predrying system integrated with heat and water recovery from wet flue gas is proposed in this study. In the proposed system, the heat source for the lignite predrying system was the latent heat from the flue gas instead of the extracted steam, so the extracted steam could return to the turbine to generate more power. Moreover, both the water from the raw lignite and wet flue gas desulfurization (WFGD) processes were recovered, which minimized the water consumption of lignite-fired power plants. This study evaluated the energy- and water-saving potential of the proposed system at both air-cooling and wet-cooling power plants firing three types of lignite separately. The results showed that the higher the moisture content of lignite, the larger the net efficiency improvement and the make-up water rate reduction. The net efficiency improvement and make-up water rate reduction in power plants firing Yimin lignite reached 2.33% points and 0.370 t/MWh, respectively, at wet-cooling power plants, and 2.18% points and 0.443 t/MWh at air-cooling power plants. This means that zero water consumption can be achieved, and water and electricity can be output at the same time at air-cooling power plants. The technical and economic analysis showed that the net present value in 10-years of power plants firing different lignite types could reach 49.31, 36.19, and 16.44 million USD depending on the predry degree. The discounted payback period was 2.34–3.67 years, which showed good economic viability in all cases.

Gravimetric and instrumental methods comparison for experimental determination of carbonate carbon content in solid mineral fuels

The content of combustible elements in solid mineral fuels (carbon, hydrogen, etc.) are very important, since they most directly affect the heat value. It should be noted that the fuel heat value depends on many other constituents, such as ash and moisture. In this paper, special attention has been paid to carbon content. In solid mineral fuels, carbon is found alone or bound in the form of various compounds. One of them is mineral carbonate compounds bound as carbonate carbon, which originates from absorbed CO2 from atmosphere. Determination of carbonate carbon content of solid mineral fuels was performed by standard gravimetric method (according to ISO 925: 2019), and newly developed instrumental method, using thermogravimetric analyzer LECO TGA 701. Comparison of obtained experimental results was done. Four types of coal, Kolubara lignite, Kostolac lignite, brown coal, and control coal sample were included in experimental analysis. In addition, moisture in the samples was also determined using analytical method and inspected using LECO TGA 701 thermogravimetric analyzer, as well as total carbon content using the LECO CHN 628 elemental analyzer. An analysis and comparison of the obtained results was performed, and comments and conclusions are presented. The experiments were done in the department for fuel characterization, Laboratory for Thermal Engineering and Energy, Institute of Nuclear Sciences Vinca.

Syngas Underground Coal Gasification (UCG) Testing of In-Situ Type Lignite Coal and Fracture Type Coal

The advancement and utilization of technology require energy, namely electricity and fuel energy. The increasing cost of fossil energy, the scarcity of non-renewable energy sources and the increasing energy demand requires diversification of energy resources. One of the new renewable energy sources currently being developed in Indonesia is Underground Coal Gasification (UCG). UCG is a new technology that utilizes unmined coal. In the UCG process, coal is burned underground and the syngas produced is collected through bore wells for processing or direct use. The resulting syngas is analyzed to see the effect of in-situ type of lignite coal and fractured type of coal on syngas production using the UCG method. Tests carried out on fracture-type lignite coal for 120 minutes with a sample weight of 1.3 kg obtained a CH4 gas concentration of 0.24%, which is relatively low compared to the in-situ type lignite coal sample CH4 gas concentration of 1.13%. The CO2 concentration was 54.46% in the fracture sample, and the In-Situ type sample was 52.19%. The O2 content with a value of 19.43% for the Fracture Type sample and 4.94% for the In-Situ type sample. Fracture Type and In-situ Lignite Coal produced fewer syngas products due to UCG testing than high-rank coals such as sub-bituminous and bituminous coal.

Syngas Characteristics from UCG Gasification Process with Lignite and Subbituminous Coal Types

Underground Coal Gasification (UCG) is the process of converting the materials used to make synthetic gas in a feasible and economically attractive manner as a method for harnessing energy from underground coal sources. Coal gasification will produce a gas producer in the form of synthetic gas (syngas) with the main components consisting of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2) and nitrogen (N2) and low pollutants. The highest temperature produced with MT 47 lignite coal using an oxygen velocity of 5 liters/minute was 2400 C at the 35th minute, while the lowest temperature was 950 C at the 95th minute. For Subbituminous AL 51 coal using an oxygen velocity of 5 liters/minute, the highest temperature is 3540 C at 75 minutes, while the lowest temperature is 1060 C at 130 minutes. At an oxygen velocity of 5 liters/minute the flash point / burn test is on the MT 47 lignite coal type in the 10th minute and at a temperature of 1700 C. Meanwhile, the AL 51 subbituminous coal type is in the 30th minute and at a temperature of 3130 C. Based on the discussion and analysis of data from the gasification test of lignite and subbituminous coal with variations in oxygen velocity of 5 liters/minute, the results obtained are that lignite coal burns faster (burn test) in the 10th minute at a temperature of 1700 C, in the subbituminous type it has higher temperature 3130 C and longer burn test at 30 minutes.

Experimental investigation on microstructure evolution and spontaneous combustion properties of aerobic heated coal

Since coal oxidation and heat accumulation are prerequisites for coal spontaneous combustion, it is of great significance to study the characteristics of coal oxidation and heat accumulation to grasp characteristics of spontaneous combustion of residual coal and to locate the area with coal spontaneous combustion in goaf. In this study, three types of lignite and bituminous coal with a strong spontaneous combustion tendency were selected to prepare raw coal samples and aerobic heated coal samples. Then ultimate and proximate test, core pore and surface area test, SEM test, TG test, FTIR test and temperature-programmed test were undertaken, respectively. After coal undergoes aerobic heated progress, its surface micro-cracks, internal pore volume and specific surface area surge, and the active functional groups vary significantly; the contents of C and H fall, and that of O rises. These changes are conducive to coal oxidation. The temperatures corresponding to the first peak points in the DTG curves for the aerobic heated coal samples are lower than those for the raw coal samples, which indicates that the aerobic heated coal samples enter the self-oxidation acceleration stage earlier. Besides, according to the results of the temperature-programmed experiment, the cross-point temperatures of CO generation for the aerobic heated coal samples and the raw coal samples are 91 °C, 82 °C and 76 °C, respectively. A comprehensive analysis discloses that the aerobic heated coal samples are more likely to combust spontaneously in the initial stage of oxidation and to generate more CO. The heat dissipation zone, oxidation zone and suffocation zone were divided by monitoring the oxygen concentration changes in goaf at different stages on 5–20101 working face. It is determined that the oxidation zone of the goaf is 71–152 m on the inlet side and 59–128 m on the return side.

Petcoke composites as HPHT fluid-loss control additive for oil-based drilling fluids

In the present work, composites based on petroleum coke (shot petcoke) and unmodified lignites as high pressure and high temperature fluid loss control additives (HPHT) in oil-based drilling fluids were synthesized and evaluated. Several petcoke composites were synthesized with coke content among 48 wt% and 85 wt%. Petroleum coke composites with lignites controlled the fluid-loss better than organophilic lignite. Petcoke composite with leonardite (a type of lignite) (FPC-L) was that showed the smaller fluid-loss (6.8 mL) in organophilic lignite (FOL) comparison (5.7 mL), because of colloidal lignite (fouling) helps plug off the permeable parts of filter-cake. Applying the reverse osmosis filtration models (Hermia’s models); the blocking mechanisms that occurred most probably were found. FOL fluid-loss control mechanism is by filter-cake formation, while FPC-L is by filter-cake fouling. Petcoke composites controlling fluid-loss by three mechanisms colloidal fouling of the cake filtration: (i) intermediate blocking, (ii) standard blocking and (iii) complete blocking. Colloidal lignite is a determinant factor in the fouling of pore volume and permeability the filter-cake. Cake filtration permeability was estimated by 1H-NMR. Use lignite-petcoke composites as fluid-loss control additive of lower environment impact for oil-based drilling fluids.

Estimation of radiological impact on residents due to household storage of coal used for heating in Serbia

This paper aims to estimate a potential radiological risk from different kinds of coals used for domestic heating in Serbia, by measuring the activity concentration of radionuclides and radon exhalation rate. The obtained radon mass exhalation rate ranges from (5.3 ? 3.1) mBqkg?1s?1 to (70.3 ? 9.4) mBqkg ?1s?1 and was highest for lignite type of coal. It is estimated that coal stored in the basement could contribute up to 50 Bqm?3 of indoor radon concentration at the ground level. Activity concentrations of 226Ra, 232Th, 40K, 238U, 235U, and 210Pb in analysed coal samples agree with previously reported concentrations of coal used in Serbia. The values of radium equivalent concentration and external hazard index indicate that the used coal does not represent a significant radiation hazard.

Electrical resistivity survey data for potential aquifer in Banggi Island, Sabah, Malaysia.

The survey data on potential aquifer was collected at two sites located in Banggi Island (i.e. Laksian Primary School [LPS] and Padang Primary School [PPS]), Malaysia on 25 and 26 April 2013. Both locations are geologically surrounded by various types of lithologies, namely, sandstone, mudstone, siltstone, shale, chert, conglomerate, lignite, tuff, limestone, terrace sand, gravel and coral. The resistivity data consisted of six-line pole-dipole short arrays and were recorded in-situ using SAS 4000 ABEM Lund Imaging System, together with a relay switching unit (Electrode Selector ES 464), six multiconductor cables, steel rod electrodes and jumpers. The data, namely electrode spacing, depth of investigation, subsurface resistivity, type of material and horizontal data coverage were used to assess the characteristics of the potential aquifer. The recorded data were then processed using RES2DINV software to obtain 2-D inversion model of the subsurface. The data were also equipped with six models of inverse resistivity section for both areas. The data obtained can be used by the government and stakeholders for groundwater exploration and extraction in order to provide water supplies for local communities, especially since access to these resources from the surrounding water treatment plants on the island is limited.

Microbial methane formation from different lithotypes of Miocene lignites from the Konin Basin, Poland: Geochemistry of the gases and composition of the microbial communities

The present research compares the yield of microbial methane production from different lithotypes of Miocene lignite from the Konin Basin in Poland and attempts to establish an understanding of the processes responsible for methanogenesis. A series of batch experiments were carried out with detritic and xylitic lignites inoculated with microorganisms from an external source (the anaerobic chamber of a wastewater treatment plant in a sugar factory). Biogas volume, concentration and stable carbon isotopes of microbial methane were measured. It was found that detritic lignites are a slightly more suitable raw material for microbial methane production than xylites. Methane yield for detritic lignites equalled 14.3 μmol CH4/g of total organic carbon (TOC); for xylites, 13.7 μmol CH4/g of TOC. The mean δ13C(CH4) value in experiments with detritic coal from Konin equalled −36.3‰; for fossil wood fragments, −47.3‰ and −42.7‰. We suppose that differences in mean δ13C(CH4) values from the biodegradation of different lithotypes of lignite from the Konin Basin most probably depend on cellulose and lignin content (%). The holocellulose content in xylites decreased over time, suggesting the important role of the enzymatic hydrolysis of cellulose to glucose. Methane from detritic lignite was formed due to lignin decomposition. Methane-producing microbial communities were dominated by Bacteria mainly from the phyla Proteobacteria (Alpha-, Beta- and Gamma- or Deltaproteobacteria), Firmicutes (Clostridia and Bacilli), Actinobacteria, and Bacteroidetes. Archaea constituted only 2–6% of the microbial community, including Methanosarcinales, Methanomicrobiales, and Methanobacteriales. The data presented here show no clear correlations between lignite type and specific bacterial or archaeal taxa. However, certain tendencies were observed. Exiguobacterium and Pseudomonas are more abundant in xylites, Rhizobacteriaceae in detritic lignites. This indicates the complexity and diversity of lignite material and processes leading to lignite degradation. In the presented research model, anaerobic oxidation of methane may occur.

Petrographic characterization, variations in chemistry, and paleoenvironmental interpretation of Colombian coals

This study focuses on variations in petrographic composition and chemistry of macerals from different coalfields in Colombia. The coal-bearing formations in Colombia occur in the age interval from the Maastrichtian in the Upper Cretaceous to the Paleogene and Neogene (Paleocene, Eocene, Oligocene, and Late Pliocene) up to Early Pleistocene. The coals range in rank from lignite to semianthracite. Petrographically, the coal is composed dominantly of macerals of the vitrinite group (>50% by volume). The coals from the regions of Antioquia, Córdoba, and Caldas are characterized by relatively high proportions of liptinite (up to 30 vol%). The inertinite contents vary up to 30 vol%, and the coals from the regions of Boyacá and Guajira contain the highest quantities of this maceral group. The Colombian coals studied have low moisture, except for the coal from Caldas being lignite type A. The sulfur content ranges between 0.28 weigh % in coal from Guajira to slightly above 2% in coal from Córdoba and Cauca.The coal facies diagrams suggest that palaeomires developed mostly under limno-telmatic to wet forest mire conditions. The ratios of microlithotypes suggest that the original peat mires evolved under fluvial, upper deltaic and brackish settings. Overall coal petrography data suggest that peat-forming vegetation and water tables in palaeomires experienced significant variations between the Upper Maastrichtian to Pliocene - Early Pleistocene period.Variations in chemistry of coal macerals reflect to large extent the coal rank variations. Specifically, with the increase in vitrinite reflectance (Ro), the contents of aliphatic functional groups decrease whereas those of the aromatic groups increase. The values of CH2/CH3 ratios also decrease with increasing coal rank (2.24 in Boyacá and 0.97 in Cauca). Expectedly, spectral differences between individual macerals are most distinct in the low rank coals (0.48% Ro).

HEAT RATE SYSTEM ANALYSIS IN THE STEAM POWER PLANT IN NIITANASA USING ENVIRONMENTALLY FRIENDLY LOW-CALORIE FUELS (REVISI)

The heat rate in a steam power plant is very important to know because it involves the amount of energy supply needed to produce electricity. This is done to determine the heat energy input from fuel needed in an electric energy. The purpose of this research is to analyze the heat rate needed in a steam power plant. The method used is the direct method, the required input is Gross kWh, Net kWh, coal fuel use, calorific value of the fuel. The type of fuel used is low calorie type of lignite. The results of the Gross Heat rate in January were seen 4,323.98 kcal / kWh while the Net Heat rate was 5,010.97 kcal / kWh. In December the Gross Heat rate was 4,141.72 kcal / kWh while the Net Heat rate was 4,992.96 kcal / kWh. This value is relatively high at a capacity of MW 100 MW.

The potential of liquid fuel production from lignite using bio-solubilization method in Indonesia

Indonesian coal reserves amounted to 20.98 billion tons, which was dominated by lignite of 59%. Its abundance, various usage, and relatively cheaper price is some of the many profitable traits for it to be used as an energy source for many industries especially in Indonesia. However, most of the type of low-quality lignite (96.4%) may result in a serious case of air pollution. For this reason, direct combustion is not an ideal process to extract energy from coal for environmental protection. This study aims to research the potential of lignite conversion into liquid fuel which considerably has less emission. A process called bio-solubilization utilizes the role of microorganisms to convert solid coal into liquid fuel/chemical compounds while still producing environmentally friendly by products. Furthermore, lignite contains simple aromatic compounds which is a favourable condition to optimize the process. Through several study review, it seems that there are still many microorganisms’ behaviours which need to be investigated further to ensure a steady process of solubilization, regardless the great potential of bio-solubilization. However, there is a hope of liquid coal production yield optimization, one of which is by pretreatment process which helps in increasing the susceptibility of brown coal to microbial solubilization.

Clay Mineralogy and Paleoclimatic Properties of the Neogene Deposits in Sinanpaşa Basin (Afyon-Western Anatolia)

The Sinanpaşa basin, one of the Neogene basins formed in the extensional tectonic regime in Western Anatolia, is located on the eastern margin of Western Anatolia basins containing different types of evaporites, lignite, uranium and clay minerals. Miocene sequence was initiated with alluvial fan- fluvial units and followed by lacustrine sediments. River floodplains and lakeshore marshes locally contain economic coal levels. Since middle-late Miocene, the products of Afyon volcanism were deposited into a subaerial or a subaqueous environment alternating with lake sediments. Dominant clay minerals are illite and smectite within the sediments coexistence with the volcanics. These minerals were accompanied by chlorite, kaolinite, and zeolite in some samples. Feldspar, dolomite, thenardite, and gypsum are locally observed too. Sepiolite mineral enrichments are also noteworthy in shallow-coastal lacustrine environments where organic matter is abundant. Clay minerals are mostly detritic and developed due to the weathering of volcaniclastics and sedimentary rocks in temperate/humid climatic conditions. In particular, smectite and kaolinite minerals were formed in situ/authigenic under subaqueous conditions due to the acidic/basic character of tuffs. As a result, different clay mineral types have been developed due to the mineralogical composition of source rocks, climatic factors (humid/semi-humid, arid), paleotopography, depositional environment and diagenetic factors.