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1
Moreea, Ruksana Goolam Hossen. "Effects of solvents and coal properties in coal liquefaction". Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324958.
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Boykov, Nikolay D. "Measurements of the electrical properties of coal measure rocks". Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4715.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains xi, 89 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 88-89).
3
Walker, Rachel Inez. "Insights into the coking behavior of southern Indiana coals bulk coal properties and individual maceral chemistries /". [Bloomington, Ind.] : Indiana University, 2005. http://wwwlib.umi.com/dissertations/fullcit/3167284.
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Thesis (Ph. D.)--Indiana University, Dept. of Geological Sciences, 2005.Title from PDF t.p. (viewed Dec. 3, 2008). Source: Dissertation Abstracts International, Volume: 66-03, Section: B, page: 1355. Co-Chairs: Maria Mastalerz; Simon Brassell.
4
Oztoprak, Ayse Feray. "Investigation Of The Rheological Properties Of Cayirhan Coal-water Mixtures". Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607861/index.pdf.
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In this thesis, coal-water mixtures (CWM) with Çayirhan lignite were prepared to optimize the parameters of CWM having an ideal behavior which means that at maximum coal loading, relatively stable at static and dynamic conditions and exhibit low viscosity. For this purpose, the effect of the parameters such as pulp density, amount of chemical agents, particle size distribution, addition of methanol and pulp pH were investigated. Results showed that increasing pulp density negatively affects viscosity and allowable maximum pulp density was obtained as 60% when the particle size distribution has a d50 value of 22.82 µ
m. The optimum amount of chemical agent was found as 0.9%, having 10% Na-CMC (Sodium Carboxymethyl Cellulose) and 90% PSS (Polystyrene Sulfonate). Minimum viscosity was achieved when the pulp pH was in natural conditions (pH=6.85). Addition of methyl alcohol increased the viscosity of CWM.
5
Man, Chi-Keung. "Some properties of cokes produced from high pressure carbonisation of coals". Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/11844.
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The British Gas Lurgi slagging gasifier is a counter-current fixed bed gasifier operating at high pressure. Coal descending the gasifier is pyrolysed to form coke which is then gasified. Properties of such coke affect the gasifier in its efficiency of operation. This thesis describes a) the carbonisation of cokes from coal under simulated gasifier conditions, b) the characterisation of the resultant cokes in terms of structure and physical properties and, c) the formulation of relationships between coal thermoplasticity and coke properties. Three high-volatile bituminous coals Manvers Barnburgh NCB 702, and Gedling (Manton NCB 502, NCB 802) were carbonised in an autoclave under a range of pressures (0.5- 8.0 MPa), using two different heating regimes, shock heating to 700 °c and slow heating to 700 °c at 5 °C/min. Physical characterisation of the resultant cokes was carried out using optical and mechanical techniques. Optical anisotropy and image analysis were used to determine coke structure and porosity respectively. Tensile strength, microstrength and abrasion resistance were measured to establish the cokes' resistance to various forms of breakage. High pressure dilatometry and plastometry were used to measure the effects of pressure and heating rate on coal thermoplastic properties. Relationships between coal thermoplastic properties and coke properties are very complex. This work has shown that these relationships are highly dependent on carbonisation conditions with heating rate rather than pressure being the more dominant parameter.
6
Heidenreich, Craig. "Mathematical modelling of large low-rank coal particle devolatilization /". Title page, summary and contents only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phh4653.pdf.
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Sloan, Elizabeth Patricia. "The influence of feedstock properties on gasification plant performance". Thesis, University of Ulster, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241681.
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Gurgenli, Hakan. "Geomechanical and weathering properties of weak roof shales in coal mines". Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4717.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains ix, 99 p. : ill. (some col.), maps (part col.). Includes abstract. Includes bibliographical references (p. 77-81).
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Stewart, Barry Robert. "Physical and chemical properties of coarse coal refuse from Southwest Virginia". Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03142009-040755/.
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Stewart, Barry R. "Physical and chemical properties of coarse coal refuse from Southwest Virginia". Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/41626.
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Coarse coal refuse is difficult to reclaim due to high potential acidity and coarse fragment content, low water holding capacity, low fertility, and other problems. Little is known about coal refuse properties, particularly as they relate to revegetation potential. This study was undertaken to determine the physical and chemical properties of composite samples from 27 coal waste piles of varying age. Selected physical and chemical properties varied widely across this sample set. The mean coarse fragment (>2mm) content of these materials was 60%. The average texture of the fine (<2mm) fraction was a sandy loam with 15% clay. The mean water retention difference, between 0.03 MPa and 1.5 MPa of soil moisture tension, on a whole sample basis was 0.08 g water/g refuse. The pH values varied from 8.3 to 3.0, and the older piles generally had lower pH values than the more recent piles. The saturated paste electrical conductivity (EC) was higher in the younger coal waste materials. Total elemental analysis revealed that Si, Al, Fe, and K were the most abundant elements in these materials. The mineralogy of three selected samples was found to be dominated by quartz in the sand and silt fraction and mica in the clay fraction. The physical factor most limiting to plant growth was found to be low water holding capacity. Low pH was found to be the chemical factor most limiting to plant survival. These findings indicate that some refuse piles may be suitable for direct seeding, but many will require heavy lime and/or organic treatments.Master of Science
11
Sadr-Kazemi, Naheed. "Estimation of coal flotation performance and froth properties using image processing". Thesis, University of Manchester, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682189.
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Reagent concentration is an important factor in froth flotation. It is also known that the froth structure plays an important role in the flotation separation achieved. The effect of surfactant concentration, conditioning time, pH and adsorption of a single reagent on froth structure and flotation performance was studied in a HaIIimond tube (micro scale) and Denver cell (macro scale). The surfactant concentration was found to be important factors in determining froth structure and stability. The appearance of the upper bubble surface of flotation froths is used qualitatively as a basis for control in industrial flotation cells. A quantitative image-processing algorithm was developed for froth surface bubble size distribution measurement that is largely insensitive to factors such as froth type, lighting conditions and bubble size. This was used to estimate the flux of bubble surface area overflowing the weir. A quantitative kinetic model based on the flux of loaded bubble surface overflowing the concentrate weir in a free-flowing froth is described. The froth is divided into two distinct phases; the bubble shells, which contain hydrophobic solids selectively, attached, and the inter-bubble lamellae, which contain non-selectively entrained solids. Quantitative relationships between the froth structure and flotation performance were determined. It was found that the froth flux relationships did not scale-up directly from micro to macro scale. A sampling technique was developed for measuring the bubble shell solids loading, which allowed the lamella thickness and solids concentration to be estimated. Based on adsorption studies and froth structure, using various reagent addition strategies was investigated to enhance the flotation performance by altering the froth structure. It was found that the flotation performance could be improved by continuous reagent addition during flotation.
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Popovych, V. V., K. V. Stepova, A. Voloshchyshyn i P. V. Bosak. "Physico-Chemical Properties of Soils in Lviv Volyn Coal Basin Area". Thesis, EDP Sciences, 2019. http://hdl.handle.net/123456789/6236.
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The results of the research showed that hydromorphous soils
prevail on the territories adjoined to waste heaps. Swampy meadow and
sod soils were defined. During investigation of swampy meadow soils it
was determined that the soil is humused at a considerable depth. The soils
are saturated with the bases. According to granulometric texture it is sandy
loam soils, but with depth go to the middle loamy soils. The analysis for
labile forms of heavy metals showed that in these soils the content of
investigated heavy metals does not exceed the maximum allowable
concentrations, except for lead. The amount of humus in sod soils sharply
decreases with depth, the reaction is close to neutral. This soil is of slightly
heavier granulometric texture. The content of labile forms of heavy metals
doesn't exceed MACs, except for lead.
13
Pandey, Rohit. "Changes in properties of coal as a result of continued bioconversion". OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1745.
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Microbial actions on coal have long been identified as a source of methane in coalbeds. Andrew Scott (1995) was the first to propose imitating the natural process of biogenic gasification, possibly leading to recharging coalbed methane (CBM) reservoirs, or setting up natural gas reservoirs in non-producing coalbeds. This study was aimed at identifying the changes in coal properties that affect gas deliverability in coal-gas reservoirs, when treated with microbial consortia to generate/enhance gas production. The experimental work tested the sorption and diffusion properties for the coal treated and, more importantly, the variation in the relevant parameters with continued bio-conversion since these are the first two phenomena in CBM production. During the first phase, single component sorption-diffusion experiments were carried out using pure methane and CO2 on virgin/baseline coals, retrieved from the Illinois basin. Coals were then treated with nutrient amended microbial consortia for different periods. Gas production was monitored at the end of thirty and sixty days of treatment, after which, sorption-diffusion experiments were repeated on treated coals, thus establishing a trend over the sixty-day period. The sorption data was characterized using Langmuir pressure and volume constants, obtained by fitting it over the Langmuir isotherm. The diffusion coefficient, D, was estimated by establishing the variation trend as a function of pore pressure. The pressure parameter was considered critical since, with continued production of methane, the produced gas diffuses into the coal matrix, where it gets adsorbed with increasing pressure. During production, the pressure decreases and the process is reversed, gas diffusing out of the coal matrix and arriving at the cleat system. The results indicated an increase in the sorption capacity of coal as a result of bioconversion. This was attributed to increased pore surface areas as a result of microbial actions. However, significant hysteresis was observed during desorption of methane and was attributed to preferential desorption from sorption sites in the pathways leading to pore cavities. This is corroborated by the increased rates of diffusion, especially for methane, which exhibited rates higher than that for CO2. This contradicted the results for untreated/baseline coal, which were in agreement with previous studies. Effort was made to explain this anomaly by the non-monotonic dependence of effective diffusion coefficient on the size of the diffusing particles, where in coalbed environments, CO2 has smaller kinetic diameter than methane.
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Hall, P. J. "The macromolecular chemistry of coals". Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377435.
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Sinka, Iosaf Csaba. "An investigation into rock and reservoir properties of coal with special reference to simulated coalbed methane performance". Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299244.
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Erdogan, Sinem Setenay. "A Preliminary Study On The Use Of Reservoir Simulation And Coal Mine Ventilation Methane Measurements In Determining Coal Reservoir Properties". Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613047/index.pdf.
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This thesis investigates methane emissions and methane production potentials from abandoned longwall panels produced or emitted due to mining activities either from coal seam or any underlying or overlying formations. These emissions can increase greenhouse gas concentrations and also pose a danger to the underground working environment and to miners. In addition to the safety issues, recovery and utilization of this gas is an additional source of energy.
In this study, methane concentrations measured from ventilation air ways in Yeni Çeltek Coal Mine, which is located in Suluova basin, Amasya, and contains thick, laterally extensive Lower Eocene coal seams, were integrated within a numerical vi reservoir model. Key reservoir parameters for history matching are cleat permeabilities, cleat porosity, diffusion time and Langmuir volume and Langmuir pressure. Thirteen cases were studied. According to the results, Case-10 determined as the best fitted case for both of the production wells. Cleat permeabilities and Langmuir pressure were the most effective parameters. Reservoir parameters matched are cleat permeabilities of 5, 4 and 1 md and fracture dimensions of 0.8, 0.4, and 0.1 m in x, y and z direction respectively, 2 % cleat porosity, 0.3 % water saturation. Diffusion time was determined as 400 days and 2000 kPa Langmuir volume and 6.24279 m3 /tone gas content estimated. According to these results it can be said that methane production will not be economically feasible, however
to remedy underground working conditions and safety of workers methane management should be taken into consideration.
17
Johnson, Angelo Gerald. "Assessing the change in hydro-geochemical properties of fly ash over time when disposed into opencast coal mines in Mpumalanga, South Africa". University of the Western Cape, 2019. http://hdl.handle.net/11394/6927.
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Masters of ScienceEskom supplies to 95% of South Africa’s energy needs and it primarily comes from coal combustion at their coal–fired power stations. Large volumes of fly ash are generated at these coal-fired power stations as a by-product of the coal combustion process. Fly ash is disposed onto landfills at the respective power stations and these landfills are currently running out of storage space. Subsequently, there are concerning environmental impacts upon the natural water environment resulting from coal mining. More specifically, the discharge of acid mine (AMD) water from historical coal mines impact negatively on the water quality in the nearby rivers and dams in the Witbank area. Therefore, as a consequence of the limited space at fly ash landfills, Eskom has embarked on finding alternative ways to re-use fly ash in different applications such as: soil amelioration and land reclamation, road construction as well as brick and cement development. This study focussed on the feasibility of disposing fly ash into the backfill of historical and future coal mines with the intention to firstly reduce fly ash disposal at existing landfills and secondly to improve the decant water quality of the coal mines in the Witbank area. Globally, fly ash has been successfully used in mine backfilling and AMD treatment in countries such as United States of America and India, due to cementitious properties of their fly ash. However, there is limited knowledge on how South African fly ash would behave under backfilled conditions of opencast coal mines where it will be exposed to acidic water environments. This is due to the fact that South African fly ash is considered a Level 3 type hazardous waste, due to its heavy metal concentrations. This waste classification is unique and the strictest compared to global classifications and these methodologies specify that fly ash should be disposed onto lined waste disposal sites due to the potential leaching of heavy metals from these waste sites. It is important to understand the hydrogeological and hydro-geochemical properties of fly ash over time once it is exposed to acid mine water. Field and laboratory tests were conducted to understand these hydrogeological and hydro-geochemical properties of fly ash. Falling head hydraulic tests were conducted at two existing ash landfill sites to determine the hydraulic conductivity (K) of ash of different age. The results exhibit a decreasing trend in K with increasing age. This is due to the pozzolanic nature of fly ash and secondary mineralization of gypsum which causes the fly ash to harden in the presence of water from irrigation for dust suppression together with precipitation over time. Laboratory testing included the use of constant head Darcy column tests to determine the change in K and geochemical properties of the leachate over time. Natural AMD with a pH of 2.5 and a metal composition was used as influent and the leachate were routinely collected and analysed for metal concentrations. The hydraulic conductivity of the fly ash showed a decreasing trend over time. During the placement of coal ash, the moisture allows pozzolanic reactions to solidify the coal ash and lowers the K, towards 10-1 m/d, relative to fresh ash. Secondary mineralization of calcium minerals, in the coal ash contributes to a further decrease in the K, by another order of magnitude from 10-1 m/d towards 10-2 m/d. Sulphate and iron minerals from the AMD also played a major role in the decreasing K as they accumulate in void spaces and having a clogging effect, decreasing the K to 10-3 m/d. The alkaline nature of the coal ash initially neutralizes the acidic levels of AMD from an inflow pH = 2.5 to an outflow pH = 11. Acidification of the outflow towards a pH = 4 was observed, due to large volumes of AMD (>80 000 mL) flowing through short coal ash columns. The K decreased to 3 orders of magnitude, from an initial 10-1 m/d to 10-3 m/d, with the AMD iron (>150 mg/L) and sulphate concentration (>2000 mg/L) playing the dominant role in reducing the hydraulic conductivity. From the geochemical leach test results, it was observed that most of the leachate water was of a better quality than the influent AMD water quality. The outflow pH (pH = 11 to pH = 4) was higher than the pH of the inflow AMD (pH = 2.5). Overall EC reduced in discharge compared to inflow AMD (ECinflow: 535 – 545 mS/m versus ECoutflow: 350 – 490 mS/m), although Na and K in the leachate exhibited higher concentrations (10+2 mg/L) compared to the AMD inflow concentrations (10+1 mg/L). However, most of the other chemical elemental concentrations such as Fe (10-2 – 10+1 mg/L), Si (10-2 – 100 mg/L), Al (10-2 – 10+1 mg/L), Mn (10-2 – 10+1 mg/L), Cr (10-3 – 100 g/L) and SO4 (10+2 – 1+3 mg/L) in the discharge showed lower concentrations when compared to the inflow Fe (10+2 mg/L), Si (100 mg/L), Al (10+1 mg/L), Mn (10+1 mg/L), Cr (10-2 mg/L) and SO4 (10+3 mg/L) concentrations. These results show how fly ash backfill may impact on the current coal mining environment. Overall, the laboratory hydraulic conductivity and geochemical testing showed promising results for fly ash backfilling. Based on this research, fly ash can be used to alter the existing coal mining environment as it is currently known in the Witbank area. The topography, hydraulic conductivity and the water table within the backfill can be altered to improve decant water quality of ash backfilled coal mines.
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Han, Bing. "Studies of metallurgical coke behaviour and properties under conditions relevant to the bosh and deadman regions of a blast furnace". Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/28134.
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The primary aim of this study was to examine changes in coke properties in an attempt to establish a better understanding of the behaviour and degradation mechanism of metallurgical coke in the unfavourable mechanical, thermal and chemical environment of a blast furnace. The attainment of such knowledge would assist coke manufacturers and blast furnace operators to monitor and tailor the properties of the metallurgical coke to meet the optimum requirements necessary for efficient furnace operation.
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Block, Pamela Rose. "Monitoring the Effects of Surface Coal-Mine-Reclamation on Soil Biological Properties". Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/29272.
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Surface coal mining is a large-scale disturbance that disrupts soil properties that requires reclamation. Reclamation monitoring and success typically focuses on vegetation communities, but soil monitoring may improve our understanding of barriers to reclamation success. In this study, we assessed biological presence in stockpiled soils using seed viability screening and phospholipid fatty acid analysis. We found microbial communities had distinct shifts in structure, declines in overall abundance of organisms with increased stockpile depth, and that total seedling emergence was lower in stockpiled soils than the reference site. In addition, we measured carbon pools, vegetative cover, and other edaphic properties in a chronosequence of reclaimed mine land (chapter two) in order to quantify how reclamation affects soil properties. We found disturbance affected all soil properties at every treatment (years since reclamation) and that all soil carbon pools measured were significantly (p <0.005) lower than that of the reference site.North Dakota Industrial Commission Lignite Energy Counsel
20
Zhang, Yihuai. "Microstructure and Nanoscale Rock Mechanical Properties of Coal: Applications to CO2 Storage". Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/65384.
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In this thesis, the coal microstructure was investigated to better understand the related nanoscale rock-mechanical properties, and morphological changes for different effective stresses and during water and CO2 adsorption, including related porosity and permeability changes. Using in-situ reservoir condition x-ray micro-computed tomography imaging, it was observed for the first time how the micro cleat structure inside the coal matrix closed induced by supercritical CO2 flooding in-situ, and associated fracturing of the mineral phase.
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Vosolo, David A. "Investigation on geotechnical engineering properties of coal mine spoil subjected to slaking". Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/109789/1/David_Vosolo_Thesis.pdf.
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This research project has led to the development of a new approach to assess the saturated and unsaturated properties of soil material subjected to slaking. Constant saturation along with overburden pressure resulted in a larger vertical deformation ofInvestigation on geotechnical engineering properties of coal mine spoil subjected to slaking the slaking chambers; which is indicative of slaking, these results indicate that material slaking was occurring due to saturation and overburden pressure. This will have a substantial benefit to the mining operations with distinctive interest associated to safety of the mine spoil slopes, limiting failures to protect workers, equipment, and operational costs.
22
Newman, J. "Paleoenvironments, coal properties and their interrelationship in Paparoa and selected Brunner coal measures on the West Coast of the South Island". Thesis, University of Canterbury. Geology, 1985. http://hdl.handle.net/10092/4904.
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An extensive study of Paparoa Coal Measures (Upper Cretaceous - Paleocene) and Brunner Coal Measures (Paleocene - Eocene) in 3 major West Coast coalfields has been undertaken, incorporating data from field exposures and drillholes, coal petrology, and interpretation of coal analyses.
Earlier paleogeographic interpretations for Paparoa Coal Measures at Greymouth Coalfield are amplified and links established with Pike River Coalfield, where Paparoa Coal Measures are described and inferred to represent more proximal sedimentation in a narrow fault-bounded basin common to both coalfields. It is proposed that syndepositional differential subsidence acted in both areas to localise major fluvial channels to zones of most rapid subsidence. The complex paleogeography caused by sedimentation in a tectonically active sedimentary basin was locally more favourable for accumulation of thick clean peat than would be expected if the basin had subsided uniformly.
Petrological studies demonstrate that, despite an overwhelming predominance of vitrinite, both Paparoa and Brunner coals exhibit significant variability in maceral characteristics and assemblages, which can be related principally to swamp drainage. Type variation is manifest not only by maceral characteristics but also by substantial variability in volatile matter yield and vitrinite reflectance, which exhibit a linear inverse relationship in isorank (equal thermal maturity) samples, attributed to variability in peat oxygenation.
Relationships between variability in (a) lithostratigraphic characteristics, such as member thickness, texture and composition, and abundance of coal, (b) seam thickness and coal quality, and (c) coal type, including any analytical property which varies as a consequence of type variation, are used in detailed paleogeographic and paleoenvironmental reconstruction, with emphasis on coal swamps and their interaction with adjacent sedimentary environments. The resulting models are proposed as a basis for seam correlation in situations where paleoenvironmental complexity causes rapid variations in seam thickness and quality. Several case studies including both intermontane Paparoa and marginal marine Brunner Coal Measures are demonstrated.
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Badenhorst, Mathys Johannes Gerhardus. "A study of the influence of thermal drying on physical coal properties / M.J.G. Badenhorst". Thesis, North-West University, 2009. http://hdl.handle.net/10394/3989.
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One of the major issues facing the coal industry today is the decline in economically
recoverable reserves, especially in the Witbank 1 Mpumalanga region of South Africa. This necessitates a critical review of alternate coal sources. One such source was identified as previously discarded and currently arising coal fines. It is well known that great value lies within
these fines, but that the high moisture content associated with fine coal leads to thermal inefficiencies, handling problems and increased transport cost. This study will investigate thermal drying as a feasible solution to effectively remove this moisture. During thermal drying coal is fed into a high temperature environment; this can influence the physical and mechanical properties of the coal. The effects include swelling, caking, cracking, loss of water, loss of volatiles, and many more. These effects are investigated by means of
thennogravimetric analysis, scanning electron microscopy with a heating stage, proximate analysis and mercury intrusion. Coal samples with an average particle size of 500 um were selected for this study. It was found that: The rate of moisture loss up to temperatures between 150 and 200°C is at a maximum where after the rate declines up to temperatures between 350 and 450°C when primary devolatilisation initiates.
No visual changes in the coal are observed up to temperatures between 350 and 450°C.
A limited amount of volatiles evolve at a constant rate up to 250°C; this is not significant enough to decrease the calorific value of the coal.
Porosity changes in the coal are observed from temperatures as low as 250°C.
Thermal drying was found to be a feasible alternative to currently employed drying methods with 150°C selected as the optimal drying temperature. A thermal drying plant is proposed with recommendations for future work needed to realise such a plant.Thesis (M.Ing. (Chemical Engineering))--North-West University, Potchefstroom Campus, 2010
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Adeboye, Oyeleye Oluwafemi. "Effects of coal composition and fabric on porosity, sorption capacity and gas flow properties in Western Canada Sedimentary Basin coals". Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/31137.
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Porosity, methane sorption capacity, diffusivity and permeability of a suite of vitrinite-rich coals from the Horseshoe Canyon and Mannville formations of the Western Canada Sedimentary Basin were investigated. Coal rank ranges from subbituminous to medium volatile bituminous, equilibrium moisture is between 2.32%-23.75%, and ash is up to 72% although < 20% on average.
Total coal porosity estimated using mercury porosimetry and helium pycnometry is between 4.4% and 18%. Helium pycnometry porosity is higher than mercury porosimetry porosity because the smaller molecular diameter of helium allows it to access coal pores which are inaccessible to mercury at test pressures. Greater vitrinite content is generally correlated with higher coal total pore area due to the abundant microporosity in vitrinite.
Coal methane sorption capacity is up to 23.5 cc/g on a moisture equilibrated basis and is up to 40.4 cc/g for dry coals. Moisture equilibrated and dry coals sorb differently due to competition for adsorption sites in coal between methane and moisture. No relationship is observed between sorption capacity and coal rank or between maceral content and sorption capacity because of the narrow rank and maceral composition of the samples studied.
Permeability was investigated on crushed coals and plugs with crushed permeability not exceeding 1.79∙10⁻² md while plug permeability is up to 0.9 md. Average diffusivity is estimated to be around 10⁻¹¹ to 10⁻¹² m²/s.
Coal matrix properties influence crushed permeability. Inertinite-rich coals have higher matrix permeability and diffusivity because of the greater macro- and meso- porosity of inertinite. Plug permeability is dependent on coal matrix properties and the presence of fractures on tested plugs. Coals with better developed fractures are more permeable than coals with poorly developed fractures at the same effective stresses.
Probe gas type influences plug permeability. Helium permeability measurements are higher than permeability measured with methane or nitrogen. Permeability difference with probe gas is attributed to a combination of different probe gas molecule size, relative swelling effects of probe gas on coal and associated changes at in-situ stress during tests.
Understanding the reasons for permeability variations in coals will help in more focused coal bed methane exploration and development.
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Yu, Hao. "GEOTECHNICAL PROPERTIES AND FLOW BEHAVIOR OF COAL REFUSE UNDER STATIC AND IMPACT LOADING". Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1416587316.
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Phillips, Lakin N. "Evaluation of Ohio Coal as Filler Material for Thermoplastic Composites". Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1512564409202248.
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Brock, D. A. "Gateroad support design and its relationship with the properties of the immediate rock mass". Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382232.
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Craig, Nina Genevieve. "Properties and Potentials of Coal Mine Soils in Southwest Virginia 29 Years After Establishment". Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/19255.
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Current reclamation research following surface mining in the Appalachian coal region seeks to measure carbon (C) and nutrient accumulation and retention under forest vegetation to better understand the role of reforestation in the re-establishment of these ecosystem services. This study capitalized on the Controlled Overburden Placement Experiment (COPE), a 29-year-old reclamation research installation in southwestern Virginia, to estimate long-term mine soil C sequestration potentials and nutrient capitals after different reclamation strategies. The COPE includes two studies, a rock mix study (RM) comparing topsoil substitutes created from different ratios of local overburden [pure sandstone (SS), pure siltstone (SiS), 2:1 SS to SiS, 1:1 SS to SiS, and 1:2 SS to SiS], and a surface amendment study (SA) comparing organic amendments [control (CON), natural topsoil (TS), sawdust (SD), and 22 Mg ha-1 (22B), 56 Mg ha-1 (56B), 112 Mg ha-1 (112B) and 224 Mg ha-1 (224B) of biosolids] on a common 2:1 SS to SiS topsoil substitute. In the RM, overburden selection significantly affected soil nitrogen (N) and C concentrations as well as many other soil chemical [e.g., available phosphorus (P), pH, and other macro- and micronutrients) and physical (e.g., sand, silt and clay contents) properties. C sequestration rates were also significantly different and ranged from 0.13 to 0.47 Mg C ha-1 yr-1. Many of the differences demonstrated relationships with the mineral make-up of the RM treatment. The SA mine soils also differed significantly in many properties after 29 years, including N, C, and many other nutrient concentrations and contents. C sequestration rates were also significantly different with the SD and 224B treatments having negative sequestration rates, and the remaining treatments ranging from 0.23 to 0.80 Mg C ha-1 yr-1. Collectively, the results demonstrate that topsoil substitutes and surface amendments show divergent trends in soil C and nutrient dynamics after nearly three decades of development and stress the importance of post- mining reclamation based on available materials and reclamation goals.Master of Science
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Bastola, Subash. "Shear strength and stiffness properties of bedding planes and discontinuities in coal measure rocks". OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1655.
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This thesis has experimentally studied the strength and stiffness properties of bedding planes and discontinuities in the immediate roof layers overlying Herrin No. 6 coal seam in Illinois. Rock joints and bedding planes are typical discontinuities in bedded rock mass and they control failure initiation and propagation of failure through the rock mass. Strength as well as deformation properties of bedding planes, joints and discontinuities are influenced by their surface roughness, inclination, intact rock properties, and pre-mining stress values and their orientation. The strength and deformation properties (stiffness values) are characterized by peak and residual strength values. Since support loads in excavations are due to deformations of the rock mass, their analysis should consider their strength and stiffness values. The overall goal of this research is to determine the shear strength and associated stiffness properties of bedding planes and joints of the immediate roof strata rocks within 25-30 ft. (7.5-9 m) overlying Herrin no. 6 coal seam (within the pressure arch zone) using direct shear tests. A shear test loading device was designed and integrated into the 150 t (1,334 kN) [*]Forney compression loading machine in the department. It was used to perform direct shear tests in accordance with ASTM D5607-08 " Standard test method for performing laboratory direct shear strength tests of rock specimens under constant normal force". The equipment also allows for determination of peak and residual friction angles along with the dilation angle. A total of 49 bedding plane samples were tested, out of which 46 (36 intact and 10 relatively weak and loose) samples passed QA/QC procedures in accordance to ASTM D5607. Samples from eight (8) different bedding planes- shale/limestone (SL), shale/sandstone (SSs), shale/bone (SB), laminated sandstone (LS), shale/shale (SS), bone/bone (BB), bone/limestone (BL), and limestone/limestone (LL) were tested. The number of samples tested for each bedding plane were: SL- 11, SSs- 8, SB- 5, BB- 4, LS- 6, SS- 9, BL- 1, and LL- 2. Moisture content and as-received unit weight values of samples range 0.9% to 5% and 111 pcf (17.5 kN/m3) to 165 pcf (25 kN/m3), respectively. Shear strength values were developed at 400 psi (2.75 MPa) normal stress. Upon failure, residual shear strengths were determined at 600 psi (4.13 MPa) and 800 psi (5.5 MPa) normal stresses to calculate the angle of sliding friction and to develop the failure criterion for each rock type. Peak and residual shear strength values at 400 psi (2.75 MPa) normal stress range 153 - 907 psi (1.06 - 6.26 MPa) and 119 - 600 psi (0.82 -4.14 MPa), respectively. The average normal and shear stiffness values are 44,000 psi/in (11.98 GPa/m) and 11450 psi/in (3.11 GPa/m). Dilation angles are typically very low (<10◦) and negative in some cases. Joint roughness values with JRC index were typically below 10. Angle of sliding friction values range from 9◦ to 42◦. Failure criterion for different bedding planes and a composite failure criterion representing the behavior of all bedding planes were developed using linear regression. A numerical modeling case study of remnant pillar stability in a southern Illinois mine was performed that used the shear strength and stiffness parameters developed above. FLAC3D, Phase2D, and LaModel were also used to assess the stability of remnant pillars. This study would significantly aid in the design and stability analysis of both surface and underground mines. Data developed can be successfully implemented in safe geotechnical design of any surface and underground structure (both civil and mining) viz. slope stability of open pit mining, subsidence prediction during longwall and room and pillar mining. Results from this thesis would significantly improve in the safe and accurate design of mine excavations. * Equipment mentioned is not for endorsement
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Kong, Lingjun. "Characterization of Mineral Oil, Coal Tar and Soil Properties and Investigation of Mechanisms That Affect Coal Tar Entrapment in and Removal from Porous Media". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5093.
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Mineral oils and coal tars are complex nonaqueous phase liquids (NAPLs), which can serve as long-term sources of ground water contamination. Very limited data are available on mineral oil and coal tar entrapment in and removal from porous media. Thus, the objectives of this research were to evaluate the behavior of these NAPLs in porous media, and investigate the mechanisms governing NAPL entrapment in and recovery from porous media.
Quantification of properties of three commercial mineral oils and six MGP coal tars reveals that mineral oils are slightly viscous LNAPLs (density: ~0.88 g/cm3; viscosity: 10-20 cP), whereas coal tars are highly viscous DNAPLs (density: 1.052-1.104 g/cm3; viscosity: 32-425 cP). Measured oil (tar)-water interfacial tensions (IFT) were lower than that of pure NAPLs. Properties of 16 field soil samples (soil particle size distribution, specific surface area, total carbon content, cationic exchange capacity and soil moisture release curves) were characterized. Correlations between residual NAPL saturation and NAPL and soil properties were developed, and show that the entrapment of NAPL dependent upon soil particle size distribution, total carbon content, NAPL viscosity and NAPL-water IFT.
Aqueous pH and ionic strength were found to influence the interfacial properties in tar-water-silica systems. At pHs greater than 7.0, observed reduction in contact angle were attributed to the repulsive electrostatic force between coal tar and solid surface. When pH less than 4, hydration forces played a role on the contact angle decrease. The IFT reduction was resulted from the accumulation of surface-active molecules at the tar-water interface. The effect of ionic strength on interfacial properties was not significant below 0.5 M.
The effects of temperature and surfactant or surfactant/polymer addition on coal tar removal was investigated by conducting coal tar displacement experiments at three different temperatures (22, 35, and 50??with sequential flushing of water, surfactant and surfactant/polymer. Coal tar removal from porous media was enhanced by elevating temperature and surfactant flushing due to the viscosity and IFT reduction, respectively. Xanthan gum was used as the polymer to increase the viscosity of the displacing fluid. In summary, these results provide tools for the prediction of NAPL entrapment in porous media, and for the selection of remediation strategies for coal tar contaminated source zone.
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Jameson, David Edwin. "The occurrence and properties of intraformational weak horizons in the coal measures of Northern England". Thesis, University of Newcastle Upon Tyne, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283941.
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Barkhordarian, A. "Laboratory studies of pumping characteristics of processed liquid tailings with particular reference to stability and time dependant properties". Thesis, University of Nottingham, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384642.
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Spero, Christos. "The influence of coal properties on the grinding and wear characteristics of ring-and-ball pulverisers". Thesis, Queensland University of Technology, 1989. https://eprints.qut.edu.au/36451/1/36451_Spero_1989.pdf.
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This research project was broadly aimed at defining the influence of
coal properties on the grinding and wear characteristics of
ring-and-ball pulverisers.
Work undertaken included a critical review of relevant literature
concerned with the grindability and abrasion characteristics of coal,
the characterisation of coals used in relation to the pulverisers
considered, and correlation of these properties with actual
pulveriser grinding performance and wear life.
Results presented demonstrate the applicability of several model
tests to the quantification of 'hard to grind' material and the
relative grinding-energy input required for a particular coal; the
influence of coal mineralogy and physical properties on abrasiveness;
and the effect of bulk mechanical properties and moisture content on
abrasive wear of grinding surfaces. The influence of several coal
properties on performance characteristics such as capacity and
throughput, product fineness and power consumption, and wear of
grinding elements, was quantified. In addition, a semi-empirical
model describing grinding ball wear rate in terms of pulveriser
tribo-mechanical characteristics, product output and coal
abrasiveness, was developed.
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Allen, Tristan. "Susceptibility of rehabilitated mine batter surface to mass movement". Thesis, Federation University Australia, 2018. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/168528.
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The goal of the research is to quantify coal properties that may affect the processes and controls governing rehabilitated brown coal mine surface mass movements. The research investigates weathering of coal and assesses the difference in strength characteristics between fresh and weathered coal. In addition to quantifying the mechanical properties of coal surfaces in a rehabilitated slope, permeability changes due to weathering of coal are also investigated. Changes in coal strength influence sliding resistance. Changes in coal permeability impact pore pressures above the coal surface, which may also affect sliding resistance on the coal – cover interface. To assess these issues, direct and residual shear tests were used to investigate the changes in shear strength due to weathering at low normal stresses applicable to shallow cover materials. Testing was undertaken with abrasive surfaces to simulate sliding on the contact coal surface beneath cover materials assuming that the cover material is stronger than the coal. The roughness of the abrasive surface proved to be unimportant for large strain shear strength. The shear strength for coal with different weathering and normal effective stresses was examined. Coal cohesion was found to be low, but some rebinding of coal would occur with time. A coal residual friction angle of 39.1 and 37.0 degrees was found for the unsaturated and saturated tested coal respectively. Permeability tests using oxygenated water were undertaken to investigate changes to brown coal permeability as a result of weathering. Even with low levels of oxidation achievable with the permeability test apparatus, coal permeability dropped over time. While the magnitude of the reduction was not large for low oxidation magnitudes, the impact on permeability was demonstrated. A weathering index was developed as part of the study to provide a quantitative basis for assessing the weathered state of coal samples. The index employed changes to Fourier Transform Infrared Spectroscopy (FTIR) spectra to define the state of weathering. To assess the rate and magnitude of weathering of coal through oxidation an autoclave was used to artificially weather brown coal. Fourier Transform Infrared Spectroscopy and Gas Chromatography used to analyse the results. As for the permeability testing the autoclave experiments could not be run for sufficient time to progress to complete weathering by oxidation. Nevertheless the principles of the test and the equipment specifications were developed so that they could be used in future to complete the determination of weathering rates. The research has demonstrated the importance of understanding coal weathering at the upper boundary of a rehabilitated coal surface to the potential for cover mass movements due to sliding at the coal cover interface.Masters by Research
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Bode-Jimenez, Gabriel. "ASSESSMENT OF POTENTIAL IMPACTS TO SUBSURFACE BODIES OF WATER DUE TO UNDERGROUND COAL MINING". UKnowledge, 2017. http://uknowledge.uky.edu/mng_etds/35.
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Underground coal mining operations induce ground movements, which may impact overlying hydrogeologic systems. Potential impacts mainly include changes in the hydraulic conductivity of overlying strata, decreasing of the hydraulic head and changes in water flow. The present research quantifies potential hydrogeologic impacts caused by underground mining through modeling of pre- and post-mining hydrogeologic systems.
Three-dimensional conceptual hydrogeologic models were constructed with the Processing Modflow for Windows software package (PMWiN). The models are based on an actual case study, but were simplified in terms of geometry and material properties. Water flow was simulated under changing hydrogeologic properties. A number of scenarios were investigated including models with horizontal or inclined topography, featuring an aquifer overlying two longwall panels. The hydrogeologic properties of the models were estimated based on empirical relationships between the post-mining hydraulic conductivity and strain in the overburden. The strain regime in the overburden was estimated using the Surface Deformation Prediction System (SDPS) package, which allows calculation of surface deformations due to underground coal mining.
The research focuses on changes in hydraulic heads; results indicate that hydraulic heads may decrease over undermined areas and may rebound as mining ceases. Water infiltration may occur from higher located overburden formations to lower formations due to mining induced changes in hydrogeologic properties.
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Balan, Huseyin Onur. "Modeling The Effects Of Variable Coal Properties On Methane Production During Enhanced Coalbed Methane Recovery". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609622/index.pdf.
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Most of the coal properties depend on carbon content and vitrinite reflectance, which are rank dependent parameters. In this study, a new approach was followed by constructing a simulation input database with rank-dependent coal properties published in the literature which are namely cleat spacing, coal porosity, density, and parameters related to strength of coal, shrinkage, swelling, and sorption.
Simulations related to enhanced coalbed methane (ECBM) recovery, which is the displacement of adsorbed CH4 in coal matrix with CO2 or CO2/N2 gas injection, were run with respect to different coal properties, operational parameters, shrinkage and swelling effects by using a compositional reservoir simulator of CMG (Computer Modeling Group) /GEM module. Sorption-controlled behavior of coalbeds and interaction of coal media with injected gas mixture, which is called shrinkage and swelling, alter the coal properties controlling gas flow with respect to injection time. Multicomponent shrinkage and swelling effects were modeled with extended Palmer and Mansoori equation.
In conclusion, medium-volatile bituminous coal rank, dry coal reservoir type, inverted 5-spot pattern, 100 acre drainage area, cleat permeability from 10 to 25 md, CO2/N2 molar composition between 50/50 % and 75/25 %, and drilling horizontal wells rather than vertical ones are better selections for ECBM recovery. In addition, low-rank coals and dry coal reservoirs are affected more negatively by shrinkage and swelling. Mixing CO2 with N2 prior to its injection leads to a reduction in swelling effect. It has been understood that elastic modulus is the most important parameter controlling shrinkage and swelling with a sensitivity analysis.
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JÃnior, Francisco Necy Alves. "Evaluation of mechanical properties of gypsum with the incorporation of the products of coal combustion". Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=15321.
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nÃo hÃThe accelerated industrial development of recent decades has been touted as one of the most impacting factors on the environmental imbalance. For this reason, research has been developed aiming, among other objectives, the reuse of waste generated by industrial processes as raw materials or inputs in other processes. This study aims to investigate the viability of using waste generated by the combustion of coal in power plants as an additive in the production of gypsum parts for construction. Coal combustion products (CCP) are already being applied in the construction industry as an additive in concrete, but their use in gypsum masses is very limited, which motivated the current reseach project. Initially the influence of water by varying the addition on mass in 5 levels between 10 and 50% was evaluated in order choose the best ratio water / gypsum about the mechanical properties. The materials used were characterized by fluorescence spectroscopy X-ray (XRF), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray (EDS) and scanning electron microscopy (SEM). The production process used for making the specimens was the so-called UCOS (portuguese acronym for the initials of wetting, compaction and drying), with pressure of 10 MPa. Then, test pieces were prepared with incorporation of PCC to the mass of gypsum in 5 levels between 10 and 50% to analyze the influence of these additions on mechanical properties, which was evaluated by compression tests, hardness and three point bending. The results determined that the water/gypsum (a/g) that provides the best mechanical properties is 0.2, which is used in the evaluation stage of the specimens with addition of PCC. It was concluded that, in general, increasing the incorporation of the waste was damaging to the mechanical properties of the gypsum block. Nonetheless, the studied conditions meet the requirements of NBR 13207, except for the condition with incorporation of 50% of PCC. In general, the mechanical properties behaved in similarly conditions between 10 and 20% of PCC, but the evolution from 20 to 30% caused a significant decrease in the results. Thus, it is concluded that the condition of 20% PCC in plaster and ratio a/g 0,2 meets the standard, ensures recycling of waste and, due to the pressing process, has better mechanical strength compared to the usual products.
O acelerado desenvolvimento industrial das ultimas dÃcadas tem sido apontado como um dos fatores mais impactantes sobre o desequilÃbrio ambiental. Por esse motivo, pesquisas vÃm sendo desenvolvidas visando o reaproveitamento dos resÃduos gerados pelos processos produtivos industriais como matÃrias-primas ou insumos em outros processos. Este trabalho objetiva investigar a viabilidade de se utilizar um resÃduo gerado pela combustÃo de carvÃo mineral em usinas termoelÃtricas como aditivo na produÃÃo de peÃas de gesso para a construÃÃo civil. Este produto da combustÃo de carvÃo (PCC) jà vem sendo aplicado nas indÃstrias de construÃÃo civil como aditivo em cimento, porÃm sua utilizaÃÃo em massas de gesso à bastante restrita. Inicialmente foi avaliada a influÃncia da Ãgua pela variaÃÃo da sua adiÃÃo à massa de gesso em 5 nÃveis entre 10 e 50%, visando escolha da melhor relaÃÃo Ãgua/gesso quanto Ãs propriedades mecÃnicas. Os materiais utilizados foram caracterizados por espectroscopia de fluorescÃncia de raios-X (FRX), difraÃÃo de raios-X (DRX), espectroscopia de absorÃÃo no infravermelho por transformada de Fourier (FTIR) e de energia dispersiva de raios-X (EDS) e microscopia eletrÃnica de varredura (MEV).O processo produtivo utilizado para confecÃÃo dos corpos de prova foi o de Umedecimento, CompactaÃÃo e Secagem (UCOS), com pressÃo de 10 MPa. Em seguida, foram confeccionados corpos de prova com incorporaÃÃo de PCC à massa de gesso em 5 nÃveis, entre 10 e 50% com a finalidade de analisar a influÃncia dessas adiÃÃes sobre as propriedades mecÃnicas, o que foi avaliado por ensaios de compressÃo, dureza e flexÃo em trÃs pontos. Os resultados obtidos determinaram que a relaÃÃo Ãgua/gesso (a/g) que fornece as melhores propriedades mecÃnicas à a de 0,2, sendo esta utilizada na etapa de avaliaÃÃo dos corpos de prova com incorporaÃÃo de PCC. Concluiu-se que, em geral, a crescente incorporaÃÃo do resÃduo foi danosa Ãs propriedades mecÃnicas do bloco de gesso. NÃo obstante, as condiÃÃes estudadas atendem Ãs exigÃncias da NBR 13207, exceto a condiÃÃo com incorporaÃÃo de 50% de PCC. Em geral, as propriedades mecÃnicas se comportaram de forma semelhante entre as condiÃÃes com 10 e 20% de PCC, sendo que a evoluÃÃo de 20 para 30% gerou queda significativa nos resultados de resistÃncia mecÃnica. Com isso, conclui-se que a condiÃÃo de 20% de PCC em gesso e relaÃÃo a/g de 0,2 atende à norma, permite o reaproveitamento de resÃduos e, graÃas ao processo de prensagem, apresenta melhor resistÃncia mecÃnica comparada aos produtos usuais.
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York, Christopher D. "Combustion properties of density separated inertinite macerals in the Herrin #6 and Murphysboro coal seams /". Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1796420411&sid=1&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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York, Christopher Daniel. "Combustion properties of density separated inertinite macerals in the Herrin #6 and Murphysboro coal seams". OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/473.
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The inertinite combustion reactivity of the Herrin #6 and the Murphysboro coal seams were examined. Three samples of the Herrin #6 seam were analyzed: A whole coal sample, a resonance disintegration milled sample, and a fusain lithotype sample. A fusain lithotype sample was also analyzed for the Murphysboro coal seam. Density gradient centrifugation (DGC) techniques were used to separate the inertinite components of each sample into 26 discrete density fractions. Fractions were chosen based upon changes in the density profiles. The thermal properties of the fractions were analyzed by thermogravimetric (TGA) analysis. The results showed that although the reactivity profiles for the coal samples were different, discontinuities occurred in all of the coal samples across the same density intervals. It also illustrated that the change between semifusinite and fusinite was not a continuous change as suggested by the definition (ICCP, 2001, but was instead shown to be discontinuous. Changes within the chemical structure were inferred from these discontinuities indicating differences within the semifusinite and fusinite maceral groups. The boundary between more/less reactive macerals was shown to increase with density as temperature increased indicating that at higher energies more macerals were reactive during the combustion process.
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McGrath, Hollis Joyce. "Developmental changes in chemical and physical properties of Coal Valley minesoils in the central Alberta foothills". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64970.pdf.
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Mares, Tennille Elisa. "An investigation of the relationship between coal and gas properties in the Huntly coalfield, New Zealand". Thesis, University of Canterbury. Geological Sciences, 2009. http://hdl.handle.net/10092/4453.
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The exploration for unconventional energy reserves has rapidly increased over the last five to ten years. Currently, there are a number of companies actively exploring for coalbed methane (CBM) in New Zealand. This study investigates one of these prospects, the subbituminous Huntly coalfield.
Coal core was retrieved from the two major seams in the coalfield, the Renown and the Kupakupa. Three coals types were identified (1) bright lustre, non-banded, (2) bright lustre, moderately banded and (3) bright lustre, highly banded. As the degree of banding increases, the average thickness of the vitrain bands increase, the amount of structured vitrinite macerals also increase and the vitrodetrinite content decreases. The Renown seam is predominantly composed of bright non-banded coal while in the Kupakupa seam the more banded coal types are dominant.
On average, the Renown seam has both the capacity to hold more gas and has higher gas contents than the stratigraphically lower Kupakupa seam. Additionally, gas content, on average, was found to be highest in intervals of the non-banded coal type and lowest in the highly banded coal type. Cluster analysis found that gas content is associated with hydrogen, volatile matter, calorific value and collodetrinite. As such, gas appears to be preferentially retained/produced in the matrix-dominated material. While not causally linked with gas content, gas holding capacity showed associations with the sporinite, inertodetrinite, funginite and vitrodetrinite; of note, these macerals are highest in the non-banded coal type. Gas holding capacity is thought to be a function of coal texture.
Ash yield was found to inversely affect total gas content when ash yield is >10%. Below 10%, it is thought that inorganic elements are organically bound. The small angle scattering analysis indicated that inorganic matter was in the 12.5 Å < r < 125 Å pore size range. The influence of inorganic material was more noticeable in vitrain than matrix samples and is proposed to exist as thin inorganic coatings.
Total porosity of the Huntly coal is primarily composed of micropores with macroporosity only contributing a small proportion. In addition, the specific surface area of the coals is also largely contributed by the micropores. Methane holding capacity on a dry, ash-free basis showed positive correlations with both micro- and macroporosity. When methane holding capacity was considered on an ‘as analysed’ basis, correlation was only identified with macroporosity. Possibly gas holding capacity is affected by the presence of moisture blocking access to gas adsorption sites in smaller pores.
Considerable variation is present in both gas adsorption and gas desorption results between drill holes, between seams and also within individual seam intersections. Gas adsorption capacity and gas content are used to calculate % saturation for a reservoir, a key assessment parameter. It was found that multiple samples of both gas adsorption capacity and gas content are required to reduce the uncertainty around the calculated % saturation (at least three of each in the current study). Additionally, adsorption isotherm samples need to be collected as fresh as possible to minimize oxidation and moisture loss. Delaying sample analysis was found to result in an overestimation of gas adsorption capacity.
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Jankus, Daniel James. "Antimicrobial Properties of Graphite and Coal-Derived Graphene Oxides as an Advanced Coating for Titanium Implants". Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103151.
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Prosthetic joint infection (PJI) poses a significant risk to implanted patients, requiring multiple surgeries with high rates of reinfection. The primary cause of such infections is otherwise innocuous bacterial species present on the skin that have survived sterilization protocols. Antibiotic drugs have significantly reduced efficacy due to the lack of vasculature in the newly implanted site, allowing microbes to form biofilms with even greater resistance. Graphene oxide (GO) is known to have good biocompatibility while providing drugless antimicrobial properties. The focus of this study is on the development and characterization of a robust coating for titanium alloy implants to promote bone regeneration while inhibiting microbial biofilm adhesion to the implant surface. The novelty of this study is the use of proprietary coal-derived graphene oxide (c-GO) in a biomedical application. c-GO has been demonstrated to have a greater number of functional oxygen groups to promote cell adhesion, while also maintaining thinner layers than possible with graphite exfoliation methods. As an alternative to powerful antimicrobial drugs, it was hypothesized that an advanced coating of graphene-oxide would provide a defensive, passively antimicrobial layer to a titanium implant. While GO is typically quite expensive, the newly developed process provides an economical and environmentally friendly method of producing GO from coal (c-GO). The result is a coating that is inexpensive and capable of halving the biofilm formation of MRSA on titanium-alloy surgical screws in addition to providing improved bone cell adhesion and hard tissue compatibility.Master of Science
Any time a patient receives implantation surgery, there is a chance of microbes entering the body. These are typically naturally occurring skin flora, harmless but opportunistic. On the surface of implants within the body, these bacteria can form colonies called biofilms, leading to severe and potentially deadly infections, called prosthetic joint infection (PJI). PJI often requires multiple surgeries to remedy, but rates of reinfection are relatively high. As with any surgery, patients are given antibiotic drugs, but implants to not receive blood flow as the body normally would, reducing the effectiveness of antibiotics. Once biofilms are formed, the bacteria become even hardier and resistant even to powerful antibiotics. Graphene oxide (GO) is a carbon material known to have good biocompatibility (i.e., non-toxic) while providing antimicrobial properties. The focus of this study is on the development and characterization of a robust coating for titanium alloy implants to promote bone healing while reducing microbial biofilm colonization on the implant's surface. The novelty of this study is the use of proprietary coal-derived graphene oxide (c-GO) in a biomedical application. c-GO has been demonstrated to have a different chemical makeup than graphite-derived GO, which may improve its efficacy as an antimicrobial coating. As an alternative to powerful antimicrobial drugs, it was hypothesized that a coating of graphene-oxide would provide a defensive, passively antimicrobial layer to a titanium implant. While GO is typically quite expensive, the newly developed one-pot process provides an economical and environmentally friendly method of producing GO from coal (c-GO). The result is a coating that is inexpensive and capable of halving the biofilm formation of MRSA on titanium-alloy surgical screws in addition to providing improved bone cell adhesion and hard tissue compatibility.
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Jansen, van Vuuren Melchior Changuion. "The chemical properties and derived sedimentation patterns of the coal seams in the Witbank-Highveld area". Diss., University of Pretoria, 1989. http://hdl.handle.net/2263/61056.
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From available records and data of colliery product samples, an area
within the Witbank and Highveld coalfields was selected for this study.
The petrographic and elemental nature of the coal seams have been
derived from the relationship between the volatile natter content and
the calorific value, both expressed on a dry ash-free basis (Snyman
et al, 1983; Barnard, 1987).
These derived values were complemented by ash_ analyses of colliery
product samples, paleotopographic data and seam thickness. These data
provided information on the paleoenvironmental conditions during peat
accumulation and deposition.
Computerized subsurface mapping techniques were applied to record
various chemical and petrographic parameters. The existence of major
channel complexes culminating in outwash streams towards the south is
postulated. During the formation of the basal seams these trunk
channels were up to 6 km wide and trended generally from east to west
and from north to south along loT.v gradients. The channels follow
topographical lows and skirt topographical highs. The vegetationstabilized
channels aggraded upwards at a rate consistent with peat
accumulation. The channels were fed by melt-water which originated from
the northwards receding glacial ice-cap.
Low energy currents led to the wide lateral distribution of
autochthonous coal seams. The channels led to the transportation and
redeposition of inertodetrinitric material of hypautochthonous origin.
The coal seams associated with channel areas are generally thinner and
the resultant coals are usually inertinite-rich. These coals have a
brittle character and tend to become more shaley towards the south.
A close relationship was established between the mineral matter
characteristics and coal type of the No. 2 Seam. The inertinite-rich
coals within the major channel areas contain mineral matter which is
richer in acidic minerals. These minerals are quartz, normative rutile and kaolinite. Coals which formed in interchannel areas and swamps
have generally higher vitrinite contents. The mineral matter of these
coals contains relatively more pyrite, carbonate minerals and illite.
This relationship between mineral matter and coal type is indicative of
different paleoenvironmental conditions in which the peat was formed.
Vitrinite-rich coals resulted from peats which were subjected to
brackish water conditions where moderately high pH and a lower redox
potential prevailed. The inertinite-rich coals were derived from peats
formed in acidic waters -in an aerobic environment.
Fluvial channel environments had a control on seam geometry and the
petrographic profile which characterizes coal seams. Most of the
vitrinite-rich
vitrinite-rich
coal seams
base which
have
grades
a distinctive cyclic pattern: a
upwards into inertinite-rich coal.
This petrographic pattern may be repetitive within the seam and is
mostly reversed in the coal seams which were deposited in channel areas
where a vitrinite-rich cap grades downwards into an inertinite-rich
base.
The influence of the topography of the pre-Karoo basement is evident
throughout the succession of major depositional units, especially in the
Witbank coalfield. Nevertheless, the paleoenvironments which existed
during the formation of the various seams differed in extent. The
different seams each have their own areal distribution, seam geometry
and petrographical and chemical characteristics.Van beskikbare inligting asook data van steenkoolprodukte is n studiegebied in die Witbank- en Hoeveldsteenkoolvelde uitgesoek. Die petrografiese en elementsamestellings- eienskappe van die steenkoollae is afgelei uit die verband tussen droe as-vry vlugstof en hittewaarde (Snyman et al, 1983; Barnard, 1987). Hierdie afgeleide waardes is aangevul met assamestellingsanalises van steenkoolprodukte, paleotopografiese data en lac:tgdiktes. Uit hierdie data is inligting oor die toestande wat tydens veenvorming en afsetting geheers het, ingewin. Gerekenariseerde ondergrondse karteringstegnieke is gebruik om verskeie chemiese en petrografiese eienskappe aan te dui. Die bestaan van hoofkanaalkomplekse wat na die suide uitspoelstrome tot gevolg gehad het, word veronderstel. hierdie hoofkanale tot Gedurende die vorming van die onderste lae was 6 km breed en het die roetes met n matige gradient oor die algemeen van oos na wes en van noord na suid gestrek. Die kanale volg topografiese laagtes en om topografiese hoogtes. Die plant-gestabiliseerde kanale het geaggradeer teen n tempo wat met veenvorming tred gehou het. Die voedingsbron van die kanale was smeltwaters afkomstig van die ·noordwaarts terugbewegende gletserbedekking. Lae-energie steenkoollae strome tot het n gevolg wye laterale gehad. Die verspreiding van kanale het die autochtone vervoer en herafsetting van inertodetrinitiese materiaal van hipautochtoniese oorsprong te weeg gebring. Die steenkoollae wat met die kanaalareas geassosieer is, is oor die algemeen dunner en hierdie steenkool is gewoonlik inertiniet-ryk. Die steenkool is ook bros en is geneig om suidwaarts skalierig te word. n Goeie verband tussen die mineraaleienskappe en steenkooltipe van die No. 2 Steenkoollaag is vasgestel. Die inertiniet-ryke steenkool wat in die hoofkanaalgebiede voorkom bevat mineraalbestanddele wat ryker is aan suur minerale. Hierdie minerale is kwarts, normatiewe rutiel en kaoliniet. Steenkool wat in tussen-kanaalareas en moerasse ontstaan het, het oor die algemeen n hoer vitriniet-inhoud. Die mineraalbestanddele van hierdie steenkool bevat relatief meer piriet, karbonaatminerale en illiet. Hierdie verwantskap tussen mineraalbestanddele en steenkooltipe is aanduidend van verskillende paleo-omgewingstoestande waarin die veen gevorm het. Vitriniet-ryke steenkool het ontstaan uit veen wat aan brakwatertoestande redokspotensiaal onderwerp geheers het. was waar matige Inertiniet-ryke hoe pH en n steenkool word veenvorming in suur waters onder oksiderende toestande geassosieer. laer met Rivierkanale het n beheer op laagverspreiding en die petrografiese profiel wat kenmerkend van steenkoollae is, uitgeoefen. Die meeste van die vitriniet-ryke steenkoollae het n kenmerkende patroon: n vitriniet-ryke basis wat opwaarts gradeer na inertinitiese steenkool. Hierdie petrografiese profiel mag herhaal word in n steenkoollaag en is meesal omgekeer in steenkoollae wat in kanaalareas afgesit is waar n vitriniet-ryke bocnste gedeelte van die laag afwaarts gradeer na n inertiniet-ryke basis. Die invloed van die topografie van die voor-Karoo vloer is deurgaans in die opeenvolging van die hoofafsettingseenhede waarneembaar, veral in die Witbank-steenkoolveld. Nietemin het die paleo-omgewings wat tydens die vorming van die verskeie steenkoollae geheers het, van mekaar verskil. Die verskillende lae het elk sy eie oppervlakteverspreiding, laaggeometrie en petrografiese en chemiese eienskappe.
Dissertation (MSc)--University of Pretoria, 1989.
Geology
MSc
Unrestricted
44
Oldham, R. H. "The influence of water on long-term strength properties of coal measures rocks associated with mining excavations". Thesis, University of Nottingham, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355420.
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45
Shurtz, Randy C. "Effects of Pressure on the Properties of Coal Char Under Gasification Conditions at High Initial Heating Rates". BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2877.
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The effects of elevated pressure and high heating rates on coal pyrolysis and gasification were investigated. A high-pressure flat-flame burner (HPFFB) was designed and built to conduct these studies. The HPFFB was designed to provide an environment with laminar, dispersed entrained flow, with particle heating rates of ~10^5 K/s, pressures of up to 15 atm, and gas temperatures of up to 2000 K. Residence times were varied from 30 to 700 ms in this study. Pyrolysis experiments were conducted at particle heating rates of ~10^5 K/s and maximum gas temperatures of ~1700 K at pressures of 1 to 15 atm. A new coal swelling correlation was developed that predicts the effects of heating rate, pressure, and coal rank on the swelling ratio at heating rates above ~10^4 K/s. A coal swelling rank index system based on 13C-NMR chemical structural parameters was devised. The empirical swelling model requires user inputs of the coal ultimate and proximate analyses and the use of a transient particle energy balance to predict the maximum particle heating rate. The swelling model was used to explain differences in previously reported bituminous coal swelling ratios that were measured in facilities with different heating rates. Char gasification studies by CO2 were conducted on a subbituminous coal and 4 bituminous coals in the HPFFB. Pressures of 5, 10, and 15 atmospheres were used with gas compositions of 20, 40, and 90 mole % CO2. Gas conditions with peak temperatures of 1700 K to 2000 K were used, which resulted in char particle temperatures of 1000 K to 1800 K. Three gasification models were developed to fit and analyze the gasification data. A simple 1st-order model was used to show that the measured gasification rates were far below the film-diffusion limit. The other two models, designated CCK and CCKN, were based on three versions of the CBK models. CCKN used an nth-order kinetic mechanism and CCK used a semi-global Langmuir-Hinshelwood kinetic mechanism. The two CCK models fit the HPFFB gasification data better than the 1st-order model. The fits of the gasification data with CCK and CCKN were comparable to each other. The fit of the data in CCK suggests that Knudsen diffusion may have influenced the gasification rates in the HPFFB experiments. The gasification rate parameters in each of the three models were correlated with coal rank. 13C-NMR parameters were used to estimate a structural parameter of the coal char. Char-CO2 gasification rate coefficients correlated better with this NMR-based char structure index than it did with the carbon and oxygen content of the parent coal.
46
Harris, Dean Michael. "Geotechnical properties of coal and mine pillar design in the Greymouth and Reefton coalfields, West Coast, South Island". Thesis, University of Canterbury. Engineering Geology, 2002. http://hdl.handle.net/10092/9274.
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This project has estimated coal strength in selected parts of the Greymouth and Reefton Coalfields in order to better estimate the size of pillars needed to maintain stability of the underground workings. Coal strength in known to decrease with increasing rank, and the Greymouth Coalfield displays to a very high rank gradient increasing from west to east. The mines assessed by this study were the Bishop Block, Strongman No. 2, Spring Creek, Roa and Terrace (Reefton Coalfield) Mines.
Core samples could not be obtained from all locations so 63.5mm cubes and point load tests were used, and compared to a control group of with a known UCS/cube relationship, in order to develop an equation from which a UCS equivalent value could be determined.
Coal strength drops from 24 MPa in the west (Strongman No. 2 E seam) to 1.3 MPa in the east of the coalfield (Roa mine Kimbell seam). Other coal properties also shows changes corresponding to changes in coal strength including carbon, volatile matter, ash, and the degree of cleating. Ash is the only one of these which is not related to increasing rank. Cleat frequency, which increases with coal rank has the most significant effect on coal strength.
The equations of Bieniawski and Salamon-Munro have been used for pillar strength calculations with panel pillars designed to a factor of safety of 1.6. Optimum pillar sizes for each of the locations in this study have been calculated, but small changes to these sizes may be necessary depending on local conditions such as faults and sheared zones. Pillar design must take into account the chance of pillar shearing once seam dip increases above 20° as the shear strength becomes greatly reduced with increasing seam dip. Coal from the Spring Creek Mine shows a high degree of anisotropy and so pillars have been designed for specific seam dips at this location.
Bearing capacity of the fireclay in the Terrace Mine is greatly reduced with increasing seam dip and overburden thickness, thus increasing the chances of floor heave. Pillars need to be of adequate size so as not to transfer excess overburden load to the mine floor, which would result in floor heave.
47
Du, Preez Susanna Maria. "Influence of minerals on the moisture adsorption and desorption properties of South African fine coal / du Preez S.M". Thesis, North-West University, 2012. http://hdl.handle.net/10394/8157.
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Five coal samples from the Witbank, Free State and Limpopo provinces in South Africa were studied to determine and understand the influence of minerals and other coal properties on the moisture adsorption and desorption behaviour. All the experiments were conducted in a climate chamber at isothermal conditions. The climate chamber controlled the relative humidity and temperature to which the coal particles were exposed during each experiment. The climate chamber was also equipped with a mass balance to record the increase (adsorption) and decrease (desorption) in mass, where a constant mass reading denoted equilibrium conditions. The coal samples were characterised in terms of proximate analysis, ultimate analysis, petrographic analysis, CO2 and N2 BET sorption analysis. The mineral characterisation of each coal was performed with XRF and QEMSCAN analysis, where the QEMSCAN analysis allowed for the quantitative evaluation of the minerals present in each of them. A constant particle size of +1mm –2mm was used to evaluate the adsorption/desorption characteristics for this investigation.
The characterisation results indicated higher moisture– and oxygen contents for the lower ranked bituminous coal samples compared to the higher ranked bituminous coal sample. Adsorption results also indicated that the lower ranked coals samples adsorbed the most moisture whereas the higher ranked coal sample adsorbed the least moisture. The oxygen content is an indication of the oxygen containing functional groups present on the coal surface which facilitates moisture adsorption. It was therefore expected that the lower ranked coals would absorb more moisture than the higher ranked ones.
QEMSCAN analysis revealed that the predominant mineral present in all the coals samples were the clay mineral kaolinite followed by quartz. The influence of kaolinite on the adsorption properties was investigated and no significant relationship was found. The kaolinite, however contributed more to the moisture adsorbed by the higher ranked bituminous coal in comparison to the lower ranked bituminous coals. This could most likely be attributed to the fact that the water uptake by the organic material of higher ranked coal is less than that for lower ranked coals. The amount of moisture adsorbed by the kaolinite seems to be less for lower ranked coal containing more oxygen and more for higher rank coal containing less oxygen. It can thus be said that the amount of moisture adsorbed in the different coal samples were influenced by kaolinite but to a lesser extent for the lower ranked coals. QEMSCAN analysis also displayed increased levels of calcite and pyrite present in the lower ranked coal samples and increased levels of illite and muscovite present in the higher ranked coal samples.
ABSTRACT
iv
A positive relationship was observed when comparing the amount of moisture adsorbed and illite content for coals similar in rank. Increased levels of illite corresponded to increased levels of moisture adsorbed for the lower ranked bituminous coals. There was a significant amount of illite present in the higher ranked bituminous coal but no significant increase in the amount of moisture adsorbed was observed.
Lower water adsorption surface areas were observed in comparison to CO2 surface areas. It was also found that the mineral matter present in the coal samples inhibited the CO2 adsorption surface areas.
Modelling of the experimental data indicated that the monolayer adsorption capacity, estimated by the BET model, correlated very well with the surface oxygen content of each coal sample. This is an indication that moisture is first adsorbed at the surface oxygen groups. The modified BET model described the moisture adsorption mechanism very well for each coal at the relative pressure range applicable to this study. From the modified BET model the contribution of water adsorbed due to primary and secondary sites could also be estimated. Energies for the primary sites, ranging between 44 kJ/mol and 50 kJ/mol, were higher than those for the secondary sites, varying between 42 kJ/mol and 43 kJ/mol. This indicated that the water–coal interactions in the monolayer were weaker than those interactions in subsequent layers. The parameters estimated from both models correlated very well with the values presented in the literature.Thesis (MIng (Chemical Engineering))--North-West University, Potchefstroom Campus, 2012.
48
Weniger, Susan Verfasser], Rudy [Akademischer Betreuer] Swennen i Ralf [Akademischer Betreuer] [Littke. "Coal reservoir characteristics and fluid transport properties for coalbed methane (CBM) evaluation / Susan Weniger ; Rudy Swennen, Ralf Littke". Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1162499699/34.
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Weniger, Susan [Verfasser], Rudy Akademischer Betreuer] Swennen i Ralf [Akademischer Betreuer] [Littke. "Coal reservoir characteristics and fluid transport properties for coalbed methane (CBM) evaluation / Susan Weniger ; Rudy Swennen, Ralf Littke". Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1162499699/34.
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50
El-Qada, Emad Nihad Ahmad. "Characterisation and adsorption properties of activated carbons produced from bituminous coal for the removal of dyes from aqueous solution". Thesis, Queen's University Belfast, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426794.
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