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Abstract

The new legislative provisions, regulating the trade in solid fuels in our country, draw attention to the need to develop and improve methods and methods of managing hard coal sludge. The aim of the work was to show whether filtration parameters (mainly the permeability coefficient) of hard coal sludge are sufficient for construction of insulating layers in landfills at the stage of their closing and what is the demand for material in the case of such a procedure. The analysis was carried out for landfills for municipal waste in the Opolskie, Śląskie and Małopolskie provinces. For hard coal sludge, the permeability coefficient values are in the range of 10–8–10–11 m/s, with the average value of 3.16 × 10–9 m/s. It can be concluded that this material generally meets the criteria of tightness for horizontal and often vertical flows. When compaction, increasing load or mixing with fly ash from hard coal combustion and clays, the achieved permeability coefficient often lowers its values. Based on the analysis, it can be assumed that hard coal sludge can be used to build mineral insulating barriers. At the end of 2016, 50 municipal landfills were open in the Opolskie, Śląskie and Małopolskie Provinces. Only 36 of them have obtained the status of a regional installation, close to 1/3 of the municipal landfill are within the Major Groundwater Basin (MGB) range. The remaining storage sites will be designated for closure. Assuming the necessity to close all currently active municipal waste landfills, the demand for hard coal sludge amounts to a total of 1,779,000 m3 which, given the assumptions, gives a mass of 2,704,080 Mg. The total amount of hard coal sludge production is very high in Poland. Only two basic mining groups annually produce a total of about 1,500,000 Mg of coal sludge. The construction of insulating layers in landfills of inert, hazardous and non-hazardous and inert wastes is an interesting solution. Such an application is prospective, but it will not solve the problem related to the production and management of this waste material as a whole. It is important to look for further solutions.
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Abstract

Zgodnie z Rozporządzeniem Ministra Gospodarki z dnia 16 lipca 2015 roku w sprawie dopuszczania odpadów do składowania na składowiskach (Dz.U. z 2015 r., poz. 1277) frakcje odpadów komunalnych o cieple spalania wyższym niż 6 MJ/kg nie mogą być składowane na składowiskach odpadów innych niż niebezpieczne i obojętne. Istnieje zatem konieczność wydzielenia tych frakcji i skierowanie ich do przetwarzania innymi metodami. W pracy podjęto działania w celu oszacowania wskaźników liczbowych, które pozwoliłyby na obliczanie i prognozowanie masy odpadów komunalnych wytwarzanych przez mieszkańców a mogących stanowić paliwo alternatywne, jednocześnie zmniejszając masę odpadów kierowanych do składowania. Analizie poddano liczne dane literaturowe, które dotyczą wartości opałowych oraz ciepła spalania poszczególnych frakcji morfologicznych. Wielkość wytwarzania odpadów komunalnych przez mieszkańców oraz skład morfologiczny odpadów są zróżnicowane dla różnych obszarów. Przeanalizowano strumień odpadów komunalnych wytwarzanych i zbieranych w sposób selektywny, jak też w sposób zmieszany w podziale na duże miasto (powyżej 50 000 mieszkańców), małe miasto (poniżej 50 000 mieszkańców) oraz obszary wiejskie. Ze względu na zakaz składowania odpadów dla których ciepło spalania jest wyższe niż 6 MJ/kg, założono, że frakcje takie można uznać za energetyczne, chociaż literatura podaje, że odpady stosowane jako paliwa powinny wykazywać wartość opałową na minimalnym dwukrotnie wyższym poziomie. Obowiązujący Krajowy plan gospodarki odpadami 2022 (M.P. z 2016 r., poz. 784) pozwala na zrównanie wskaźnika wytwarzania odpadów komunalnych na obszarach o różnym charakterze zabudowy na prognozowanym w 2025 roku poziomie 302–313 kg/mieszkańca/rok (kg/M/rok), jednak udziały poszczególnych frakcji morfologicznych są odmienne. Na podstawie przeprowadzonej szerokiej analizy danych literaturowych można stwierdzić, że poszczególne frakcje morfologiczne odpadów komunalnych charakteryzują się zdecydowaną zmiennością wartości opałowej. Najwyższą wartością opałową na poziomie 22–46 MJ/kg charakteryzują się tworzywa sztuczne. Wartość opałowa odpadów z tworzyw sztucznych jest wysoka, porównywalna do paliw kopalnych. Kolejne frakcje morfologiczne charakteryzują się wartością opałową, na niższym, ale również wysokim poziomie: papier i tektura 11–26 MJ/kg, tekstylia 15–16 MJ/kg, drewno 11–20 MJ/kg oraz odpady wielomateriałowe 16 MJ/kg. Wartość opałowa wymienionych powyżej odpadów generalnie przekracza 12 MJ/kg i spełnia minimalne wymagania stawiane odpadom, które mogą być stosowane jako paliwa. Pozostałe analizowane frakcje odpadowe charakteryzują się wartością opałową poniżej 6 MJ/kg. W strumieniu wytwarzanych odpadów komunalnych na poszczególnych obszarach frakcje energetyczne zajmują znaczący udział. Przy zrównanym wskaźniku wytwarzania największy udział frakcji energetycznych (powyżej 6 MJ/kg, a nawet 12 MJ/kg) obserwowany jest w odpadach generowanych przez mieszkańców dużego miasta i wynosi 39%, nieco niższy w odpadach generowanych przez mieszkańców małego miasta na poziomie 29%, a najniższy w odpadach generowanych przez mieszkańców obszarów wiejskich na poziomie 22%. Oszacowany wskaźnik wytwarzania frakcji energetycznych w strumieniu odpadów komunalnych zmienia się od 122 kg/M/rok dla obszaru dużego miasta do 67 kg/M/rok dla obszaru wiejskiego.
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Abstract

In the process of extraction and enrichment of coal waste, considerable quantities of waste material are produced, mainly the gangue and coal sludge, considered as waste or raw material. The main directions of the management development of the waste rock are the production of aggregates, the production of energy products and the liquidation works in hard coal mines and the filling of excavations. The paper proposes the extension of these activities to the use of waste material. The possibility of using aggregates or extractive waste to fill open-pit excavations has been proposed, also in areas within the reach of groundwater and the possibility of building insulation layers of waste material and the production of mixtures of hard coal sludge and sewage sludge to produce material with good energy properties. The analysis was based on the author’s own research and literature data related to selected parameters of waste material. This paper presents our own preliminary studies on the amount of combustion heat and the calorific value of coal sludge combined with other wastes such as sewage sludge. The proposed methods and actions are part of the current directions of development, but they allow the extension of the scope of use of both extractive waste and products produced on the basis of gangue or coal sludge. Due to the frequent lack of the stable composition of these materials, their current properties should be assessed each time before attempting to use them. The fact that it is important to continue research to promote existing economic use and to seek new activities or methods has been concluded.
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Abstract

Significant quantities of coal sludge are created during the coal enrichment processes in the mechanical processing plants of hard coal mines (waste group 01). These are the smallest grain classes with a grain size below 1 mm, in which the classes below 0.035 mm constitute up to 60% of their composition and the heat of combustion is at the level of 10 MJ/kg. The high moisture of coal sludge is characteristic, which after dewatering on filter presses reaches the value of 16–28% (Wtot r) (archival paper PG SILESIA). The fine-grained nature and high moisture of the material cause great difficulties at the stage of transport, loading and unloading of the material. The paper presents the results of pelletizing (granulating) grinding of coal sludge by itself and the piling of coal sludge with additional material, which is to improve the sludge energy properties. The piling process itself is primarily intended to improve transport possibilities. Initial tests have been undertaken to show changes in parameters by preparing coal sludge mixtures (PG SILESIA) with lignite coal dusts (LEAG). The process of piling sludge and their mixtures on an AGH laboratory vibratory grinder construction was carried out. As a result of the tests, it can be concluded that all mixtures are susceptible to granulation. This process undoubtedly broadens the transport possibilities of the material. The grain composition of the obtained material after granulation is satisfactory. Up to 2 to 20 mm granules make up 90–95% of the product weight. The strength of the fresh pellets is satisfactory and comparable for all mixtures. Fresh lumps subjected to a test for discharges from a height of 700 mm can withstand from 7 to 14 discharges. The strength of the pellets after longer seasoning, from the height of 500 mm, shows different values for the analyzed samples. The values obtained for hard coal sludge and their blends with brown coal dust are at the level from 4 to 5 discharges. The strength obtained is sufficient to determine the possibility of their transport. At this stage of the work it can be stated that the addition of coal dust from lignite does not cause the deterioration of the material’s strength with respect to clean coal sludge. Therefore, there is no negative impact on the transportability of the granulated material. As a result of mixing with coal dusts, it is possible to increase their energy value (Klojzy-Karczmarczyk at al. 2018). The cost analysis of the analyzed project was not carried out.
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Abstract

The new legislative provisions, regulating the solid fuel trade in Poland, and the resolutions of provincial assemblies assume, inter alia, a ban on the household use of lignite fuels and solid fuels produced with its use; this also applies to coal sludge, coal flotation concentrates, and mixtures produced with their use. These changes will force the producers of these materials to find new ways and methods of their development, including their modification (mixing with other products or waste) in order to increase their attractiveness for the commercial power industry. The presented paper focuses on the analysis of coal sludge, classified as waste (codes 01 04 12 and 01 04 81) or as a by-product in the production of coals of different types. A preliminary analysis aimed at presenting changes in quality parameters and based on the mixtures of hard coal sludge (PG SILESIA) with coal dusts from lignite (pulverized lignite) (LEAG) has been carried out. The analysis of quality parameters of the discussed mixtures included the determination of the calorific value, ash content, volatile matter content, moisture content, heavy metal content (Cd, Tl, Hg, Sb, As, Pb, Cr, Co, Cu, Mn, Ni, and W), and sulfur content. The preliminary analysis has shown that mixing coal sludge with coal dust from lignite and their granulation allows a product with the desired quality and physical parameters to be obtained, which is attractive to the commercial power industry. Compared to coal sludge, granulates made of coal sludge and coal dust from lignite with or without ground dolomite have a higher sulfur content (in the range of 1–1.4%). However, this is still an acceptable content for solid fuels in the commercial power industry. Compared to the basic coal sludge sample, the observed increase in the content of individual toxic components in the mixture samples is small and it therefore can be concluded that the addition of coal dust from lignite or carbonates has no significant effect on the total content of the individual elements. The calorific value is a key parameter determining the usefulness in the power industry. The size of this parameter for coal sludge in an as received basis is in the range of 9.4–10.6 MJ/kg. In the case of the examined mixtures of coal sludge with coal dust from lignite, the calorific value significantly increases to the range of 14.0–14.5 MJ/kg (as received). The obtained values increase the usefulness in the commercial power industry while, at the same time, the requirements for the combustion of solid fuels are met to a greater extent. A slight decrease in the calorific value is observed in the case of granulation with the addition of CaO or carbonates. Taking the analyzed parameters into account, it can be concluded that the prepared mixtures can be used in the combustion in units with flue gas desulfurization plants and a nominal thermal power not less than 1 MW. At this stage of work no cost analysis was carried out.
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