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The combustion characteristics of blends of lignite with various organic waste materials are evaluated in this study in order to assess their potential for energy recovery. Different types of municipal solid waste (i. e. paper, plastic, textile, organic), as well as sewage sludge and agri-residues (sunflower shells) samples were collected from the Western Macedonia region, northern Greece. Mixtures of each one of them with lignite in different proportions (30-50-70 wt.%) were prepared. Proximate analysis, calorific value determination, and thermogravimetry (TGA/ DTG) were performed. Thermal parameters such as ignition temperature, total weight loss, maximum rate of weight loss, peak and burnout temperatures and burnout time were determined from the TG/DTG profiles of the raw materials and their blends. The combined utilization of proximate analysis, calorific value determination and TG/DTG method proved to be an effective method for a preliminary assessment of the energetic potential of raw solid waste "combustible" materials and their blends with lignite. The analytical results revealed that most of the blends are promising for energy recovery. Regarding the raw wastes, sunflower shells were the most reactive. A non-synergistic effect was found for the blends. Organic and sewage sludge blends revealed the lowest combustibility, which is attributed to the high content of inorganic matter and the heterogeneity of these two types of wastes.

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The aim of this study was to characterise individual airborne particles collected from the Ptolemais-Kozani region (Western Macedonia), northern Greece. Throughout a 1-year period (March 2003 to February 2004), we collected several filters that captured airborne particles at seven sampling sites distributed throughout the area. The airborne particles captured on the filters were then characterised by environmental scanning electron microscopy (ESEM) coupled with energy-dispersive X-ray analysis (EDX). The particles were categorised as geogenic, biogenic and anthropogenic. The main anthropogenic airborne particles were fly ash (released from lignite-fired power plants) and carbonaceous (soot and char) and metalliferous (mainly iron- and copper-enriched) particulates. We present here characteristic ESEM and EDX spectra for the airborne particles and underline the presence of characteristic primary and secondary sulphates.

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Bottom ash samples were collected from four lignite power plants of Greece. Granulometric analysis was executed and after homogenization four distinct fractions (>1.25, 0.63-1.25, 0.18-0.63, <0.18 mm) were obtained. The samples were analyzed by X-Ray Diffraction (XRD) and Energy Dispersive System (EDS), while thermogravimetry (TG/DTG) and stereomicroscope viewing were applied for the coarse fractions. Furthermore, proximate analysis (moisture, ash, volatiles, fixed carbon) was undertaken and Loss on Ignition (LOI) and calorific values were determined. The particle size distribution revealed that bottom ash satisfies the gradation criteria for concrete and geotechnical applications. The mineral composition included mainly amorphous matter, quartz, plagioclase, calcite and gehlenite and minor amounts of pyroxene, portlandite, hematite, micas etc.. The chemical analysis showed Si, Ca, Al, Mg, Fe, S as major and Ti and K as minor chemical elements, indicating high slagging and fouling potential within the thermal chambers. Based on the chemistry and mineralogy of the bottom ash samples, a potential utilization in concrete manufacturing is discussed, taking into account certain limitations. Based on LOI, proximate analysis, calorific values and TG/DTG profiles of the coarse fractions (>1.25 mm), certain differences in the characteristics of the bottom ash of the younger and the three older power plants were observed. High amounts of unburnt carbon were determined in the coarse fraction (>1.25 mm) of all plants except the younger one, indicating a problematic combustion within the chambers and a potential of reburning these coarse material in a waste to energy application.

During a whole year (March 2003 to February 2004, several filters that capture airborne particles were collected from seven sampling sites spread throughout the Ptolemais-Kozani region (Western Macedonia), northern Greece. Environmental Scanning Electron Microscopy (ESEM), coupled with Energy Dispersive X-Ray analysis (EDX) was employed for the characterisation of the airborne particles. A classification of these airborne particles is attempted in this study. Aerosols with various morphological characteristics (angular, irregular, rounded, spherical, spheroidal, acicular), variable size (mostly between 5ßm and 20pm) and composition (aluminosilicates, oxides, carbonates, sulphates, metallic) were recognized. The airborne particulates were also categorized according to their origin. Geogenie, biogenic, anthropogenic (mainly fly ash released from lignite-fired power plants), carbonaceous and metalliferous (mainly iron and copper enriched) were the main categories. A database of characteristic airborne particles from Kozani area is being created using a simple software package, in order to help similar studies in the future.-1421http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 05/07/2020 11:44:43 | προσδιορίστηκαν στην παρούσα μελέτη), με σκοπό να βοηθήσει παρόμοιες μελλοντικές έρευνες στην περιοχή. Λέξεις κλειδιά: SEM/EDX, προέλευση, ανθρωπογενή, γεωγενή, βιογενή.

Within the Circum-Rhodope Belt in northern Greece, Middle Triassic neritic carbonate metasediments are locally intercalated with quartz-feldspar-phyric metarhyolites. In the same belt, Upper Triassic pelagic lime-marl-layered metasediments are similarly intercalated with low-grade metamorphosed basalt, dolerite and minor andesite and trachydacite. We interpret these sequences as due to magmatism active during the rifting event that eventually led to the opening of the Vardar Ocean. Despite the overprint of Late Jurassic deformation and low greenschist metamorphism, peperitic textures produced by magma-wet sediment interaction are well preserved at the contacts between the silicic volcanic rocks and the originally wet unconsolidated neritic carbonate sediments, suggesting contemporaneous magmatism and sedimentation. The mafic and intermediate volcanic rocks lack peperitic textures at their contacts with the pelagic sedimentary rocks. Thin margin parallel banding in the sedimentary members of the sequence indicates thermally affected original contacts with the mafic volcanic rocks only locally and at a microscopic scale. The absence of peperite in this case is attributed to the consolidated state of the sediments at the time of the mafic magma emplacement.Key words: Triassic, Circum-Rhodope Belt, contact metamorphism, low greenschist metamorphism, carbonate sediments, basalt and dolerite, rhyolitic peperites. be inferred about their origin. Peperites were formed where a quartz-feldspar-phyric partly extrusive rhyolitic crypto-dome and rhyolitic sills intruded Triassic neritic carbonate sediments. Descriptions of the newly recognized peperite occurrences are provided. Specific criteria to discriminate peperite from other mixed volcanic-sediment breccia facies are discussed. Where mafic and intermediate rocks are in contact with Triassic pelagic sediments, peperite is absent; instead, small scale contact metamorphic phenomena are present. The cause of the absence of peperite in this case is discussed.