In the present study the behavior of a lignite sample from Southern field, Ptolemais-Amynteon Lignite Center, is investigated during pyrolysis. Pyrolysis is a thermal depolymerization (cracking) of macromolecules in the absence of oxygen. The pyrolysis experiment was conducted three times and the pyrolysis temperatures were fixed at 600?C, 7007C and 800ΐ. A solid, black residue (carbonizate), no condensable gases and a liquid phase were produced. Course and product yields during pyrolysis are mainly influenced by such parameters as rank of the coal, final temperature, residence time, rate of heating, gas atmosphere and pressure. The weight of the solid phase is reduced during the process, depending on the quality and moisture content of the raw coal. At 800?C a weight loss of 52.95% is noted. The carbonizate contains more carbon and minerals than the starting material, but less volatile matter and moisture. The calorific value of the carbonizate is increased by the removal of low-energy components. Volatile compounds, such as C02 , CO, CH4, H2, CHm (tar), H20, H2S, NH3, are given off. A HP 6890 Gas Chromatograph was employed in this study. A thermal conductivity detector and a flame ionization detector were used to analyse the gases. Degasification began between 220 and 270?C. At the maximum temperature of 800?C, the volatile content is 4.39%. The total Gross Calorific Value of the pyrolysis gases is 42021 kJ m"3 (10036.5 kcal m3). The continuous degasification of this high-volatility lignite by pyrolysis can reduce the volatile content prior to burning, in other words, to produce a smokeless fuel (briquette). The carbonizate is briquetted with a binder in a press using a pressure of 11 bars. The briquette produced is a smokeless and odorless fuel. The energy required for the pyrolysis is obtained from combustion of the volatiles leading to a thermally autarkic process
ΠΕΡΙΛΗΨΗΤα ανθρακικά πετρώματα της Θάσου είναι ολοκρυσταλλικά και παρουσιάζουν σπαριτικό ιστό. Οι δολομί τες έχουν μικρότερο μέγεθος κρυστάλλων (0,7-1,6 mm) από τα ασβεστιτικά μάρμαρα (0,8-2,2 mm). Στους δολομίτες εκτός του ομώνυμου ορυκτού, βρίσκονται ασβεστίτης (1-10%) και ίχνη χαλαζία, αστρίων και μαρμα ρυγιών. Στα ασβεστιτικά μάρμαρα εκτός του ασβεστίτη βρίσκονται δολομίτης (2-28%), χαλαζίας (1-28%), μαρ μαρυγίες (1-6%) και κατά περίπτωση, άστριοι, αργιλικά ορυκτά και γκαιτίτης. Οι δολομίτες παρουσιάζονται καθαρότεροι όλων των μαρμάρων του νησιού με κυριώτερη ξένη πρόσμιξη το Si0 2 (<0,88%). Εκτός των δια κοσμητικών εφαρμογών τα ασβεστιτικά μάρμαρα της Θάσου είναι κατάλληλα κυρίως για την παραγωγή αδρα νών υλικών οποιουδήποτε μεγέθους κόκκων, τσιμέντου και πιθανώς φιαλών, για περιβαλλοντικές χρήσεις και ως βελτιωτικά εδαφών. Τα δολομιτικά μάρμαρα είναι κατάλληλα για την παραγωγή λιπασμάτων και πιθανώς φιαλών, καθώς και ως πληρωτικά ή λευκαντικά υλικά στις βιομηχανίες χάρτου, χρωμάτων και ελαστικών. ABSTRACTThe carbonate rocks of Thassos Island are holocrystalline and present sparitic texture. The dolomites have smaller crystall size (0.7-1.6 mm) than the calcitic marbles (0.8-2.2 mm). In the dolomites except the synony mous mineral, calcite (1-10%) and traces of quartz, feldspars and micas are present. In the calcitic marbles except of the calcite, dolomite (2-28%), micas (1-6%) and occasionally feldspars, clay minerals and goethite occur. The results of chemical analysis agree with the mineralogical ones, as well as with the percentage of the isnoluble residue. The dolomites appear purer than all other marbles of the island. They most often contain Si0 2 (up to 0.88%). Beyond the decorative applications the calcitic marbles of Thassos are mainly suitable for the production of aggregates with any size requirement, cement and probably container glasses, for environmental uses and as soil conditioners. Respectively, the dolomitic marbles are suitable for the production of fertilizers and probably of container glasses and as fillers or whitenings in paper, paint and rubber industries.ΛΕΞΕΙΣ ΚΛΕΙΔΙΑ: ανθρακικά πετρώματα, βιομηχανικές χρήσεις, Θάσος.
Sixty-five marl samples were collected from the outcrops of six active and one abandoned mine of Ptolemais-Amynteon Lignite Center, Northern Greece. Core samples were also collected from the West Field, a Neogene lignite deposit located at the same area. The concentrations of 39 trace elements were determined using Instrumental Neutron Activation analysis (INAA) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Carbon and sulfur contents and the loss on ignition of the samples were also determined. The classification of the trace elements concentrations in each mine and their statistical processing allows determining the horizontal and vertical distribution in the coal deposits and in the entire basin. Regarding the vertical distribution of elements and geochemical groups, significant variations of the concentrations in both the different marl seams and the upper, intermediate and lower lignite seams were determined. The mining, processing, transportation, storage and utilization of marls release, among others, some amounts of trace elements into the environment. However, the low concentrations of all trace elements, except Pb in the South field, compared to the upper mean values of world rocks Crust (W.C-U.M.V) (enrichement factor <0.8) is of great environmental concern and prove the non hazardous role of the marl during mining, beneficiation and usage.
Standard mixtures of amorphous material (volcanic glass) and crystalline phase (equally participated montmorillonite, muscovite, heulandite, quartz, and calcite) were prepared at the following weight proportions after weighting: 100-0, 75-25, 50-50, 25-75 and 0-100, respectively. From their XRD patterns and using two different techniques of analysis the percentage of amorphous material was calculated. The pure amorphous and crystalline standard mixtures constituted the mixtures of report. The area of the broad background peak of the amorphous material determined using the analogical technique and its percentage was calculated by comparing the measured area to the area of the 100:0 standard mixture, while with the second technique was appreciated the crystallinity of each standard mixture and from this resulted the percentage of amorphous material. It was found that between the two methods there is a very good identification and their divergence concerning the weighed percentages varied between ±3 wt. %. The percentage proportion of minerals based in the values resulted from the application of mass absorption coefficient is in very good agreement with the weighted proportions. The method of Powder X-Ray Diffraction can constitute a very good tool for the semi-quantitative calculation of the amorphous material contained in a sample.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.