Characterisation of lignite lithotypes from the “Kovin” deposit (Serbia) - implications from petrographic, biomarker and isotopic analysis

Abstract

Four lignite lithotypes (matrix coal, xylite-rich coal, mixture of matrix and mineral-rich coal and mixture of matrix and xylite-rich coal), originating from the Kovin deposit, were investigated in detail. The paper was aimed to determine the main maceral, biomarker and isotopic (?13C) characteristics of investigated lithotypes. Based on these results the sources and depositional environment of organic matter in 4 lithotypes were established. These samples were also used as substrates for investigation of the influence of diagenetic alteration on ?13C signatures of biomarkers, as well as for assessment of the most convenient utilization for each lithotype. The investigated lithotypes differ in accordance with the composition of huminite macerals. Xylite-rich coal notably distinguishes from other lithotypes beacuse of the highest content of conifer resins vs. epicuticular waxes. The mixture of matrix and mineral-rich coal is characterised by the greatest contribution of algae and fungi and the most intense methanotrophic activity at the time of deposition. In all coal lithotypes diagenetic aromatisation influenced isotopic composition of individual biomarkers. Xylite-rich coal has the poorest grindability properties. However, this coal lithotype is the most suitable for fluidized bed gasification, whereas the mixture of matrix and mineral-rich coal has the lowest applicability for this process. The calorific value decreases in order: xylite-rich coal > matrix coal > mixture of matrix and xylite-rich coal > mixture of matrix and mineral-rich coal. The increase of organic carbon content and calorific value is controlled by the increase of contribution of wood vegetation vs. herbaceous peat-forming plants, as well as by stability of water table during peatification. [Project of the Ministry of Education, Science and Technological Development of the Republic of Serbia, Grant no. 176006 and Grant no. 451-03-01039/2015-09/05]

Study of the Synergetic Effect of Co-Pyrolysis of Lignite and High-Density Polyethylene Aiming to Improve Utilization of Low-Rank Coal

“…Lignite and low-rank bituminous coal have huminite/vitrinite reflectance (Rr) in the range from 0.30 to 0.50% and cannot be used for coking. Our previous investigations showed that Serbian lignite is not suitable for coal briquetting, whereas a very limited Polymers 2021, 13, 759 2 of 25 number of samples possessed certain potential for fluidized bed gasification [2,9]. Most lignite is used in thermal power plants.…”

Energy and emission properties of burley tobacco stalk briquettes and its combinations with other biomass as promising replacement for coal

“…Speaking of heat value, only corncob and sawdust briquettes and their mixtures with tobacco stalks meet the standard of ≥16.0 MJ/kg (45), but considering that they are renewable energy sources and that their nitrogen and sulphur content is lower than that of coal (46)(47)(48)(49), all biomass combinations are acceptable as biofuel. Another reason to replace coal is that the calculated CO 2 emission factor is about 100 tCO 2 /TJ lower.…”

Distribution of major and trace elements in the Kovin lignite (Serbia)

“…Previous petrographic investigations (ERCEGOVAC et al, 2006;ŽIVOTIĆ et al, 2005ŽIVOTIĆ et al, , 2007 performed on samples from several boreholes from the I and II coal seam, showed that the lignite from the Kovin deposit is a typical humic coal with vari able huminite, liptinite and inertinite contents, and a mean ran dom huminite reflectance of 0.30±0.03 (ERCEGOVAC et al, 2006). Recent petrographic and organic geochemical investiga tions (MITROVIĆ et al, 2016(MITROVIĆ et al, , 2017 confirm the variation in maceral and lithotype composition in both fields and all three seams with diagenetic alteration governed by chemoautotrophic, methanotrophic and heterotrophic bacteria. The same samples were used to determine the content and distribution of major and trace elements in the coal.…”

“…The fortyfour lignite samples were collected from four bore holes, GD601 and GD603 from the A field, and KB79 and KB 91 from the B field, Kovin deposit, as described in detail in MITROVIĆ et al (2016MITROVIĆ et al ( , 2017Fig. 1;Table SI of the Supplemen tary Material).…”