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The importance of organic sulphur fixation in the preservation of organic matter in humic coal-forming environments is demonstrated in this thesis. The transgression of coal depositional systems by marine waters during their deposition and early diagenesis enables the production of reduced inorganic sulphur species by sulphate-reducing bacteria. The presence of these reactive sulphur species, in combination with the altered chemical and microbial regime, influences the preservation and petroleum potential of humic coal.Three lignite samples taken over a two meter depth profile of a core in the Eocene, Heartbreak Ridge lignite deposit, SE Western Australia, were analysed by a suite of geochemical techniques to identify origins and transformation pathways of their organic matter. Rock-Eval, FTIR microscopy, and pyrolysis gas chromatography-mass spectrometry (Py-GCMS) indicate that the composition of the lignite and its extract are typical of immature type III organic matter with a predominance of aromatic and oxygen containing functionalities. Variation in the macromolecular composition of the three lignites are consistent with more pronounced degradation of the organic matter in the lowermost lignite horizon. Nickel boride desulphurisation of polar and asphaltene fractions of the lignites showed the presence of sulphur-bound higher plant triterpenoids, in particular olean-12-ene, n-alkanes of even predominance, C29 steranes and extended 17â(H),21â(H)-hopanes. Deuterium labelling experiments indicated that these components were mostly bound to a single sulphur, at sites about the original functionality in the natural product precursors. The presence of singularly sulphur-bound aromatic ring A degraded and pentacyclic triterpenoids represent the spectrum of aromatic triterpenoid intermediates undergoing diagenesis before sulphur incorporation.Stable carbon isotopic ++ / analyses of the free and sulphur-bound aliphatic hydrocarbons confirmed carbon sources from both higher plants and bacteria. Oxygenated lipids consisted of even carbon-numbered n-alkanoic monocarboxylic acids, ù-hydroxy fatty acids and n-alkanols, n-alkan-2-ones, 6,10,14-triinethylpentadecan-2-one, and oxygenated hopanoids and higher plant triterpenoids. BY the onset of sulphurisation in the Heartbreak Ridge lignite, extended hopanoid degradation had come to a hiatus, in marked contrast to the variable alteration of the higher plant triterpenoids. The oxygen-containing lipids of the extracts are implicated as the primary source of the sulphurised hydrocarbons, although not necessarily via direct sulphurisation of their present sent form, but through the formation of more reactive intermediates. These results implicate sulphur fixation as a means by which lipids of similar structures to the natural product precursors are preserved in coal forming environments. That diagenetic alteration of the oxygenated lipids mirrors that of the sulphur-bound hydrocarbons confirms that the onset of marine incursion and the formation of reduced inorganic sulphides does inhibit (and also preserve) the normal biogeochemical transformations of organic matter in coal-forming environments.The technique of reaction gas chromatography-mass spectrometry (R-GCMS) was also applied to the analysis of the polar extracts from a Heartbreak Ridge lignite, together with the polar extracts from the Monterey Formation shale (Naples Beach, USA; Miocene age). Palladium black acting as a catalyst under hydrogen carrier gas in the vaporising injection port of a GCMS, effected gas phase reaction of the volatile constituents in the polar mixtures.The fully active catalyst effected hydrogenation, desulphurisation and decarbonylation/decarboxylation reactions. Polar fractions of the Heartbreak Ridge lignite ++ / reacted to produce angiosperm-derived triterpenoids and bacterially-derived hopanoids. The reaction of the Monterey Formation shale polars resulted in the formation of high relative amounts of pristane and phytane with a predominance of the latter, as well. as a suite of steroidal and triterpenoid moieties, typical of marine organic matter. However, R-GCMS provided less detailed information on the exact nature of the functionalised lipids partitioned within the polar fraction than that obtained by more conventional wet chemical analyses.The compositions of 35 marine-influenced, bituminous coals, from the Eocene Brunner Coal Measures of New Zealand were studied to assess the effect of the timing of marine incursion on the molecular characteristics of coals. Based upon their stratigraphic position and their volatile matter and total sulphur contents, coal samples were classified into those where the mire was flooded during or at the end of deposition (Class A/B) and those that experienced postdepositional access of marine water during later diagenetic stages (Class C/D). Rock-Eval pyrolyses showed that sulphur-rich Brunner coals generally display moderate increases in pyrolytic yields with respect to the low-sulphur Brunner coals. Class A-C coals generally release larger quantities of hydrocarbons during Rock-Eval pyrolysis than the Class D coals, suggesting that sulphur fixation can enhance the hydrocarbon potential of buried mires, provided sulphur is introduced early. Variation in Carbon Preference Indices, isoprenoid/alkane ratios, the Methylphenanthrene Index and phenanthrene/anthracene of bitumens and pyrolysates both within different seam profiles and between different sampling localities can be attributed to changes in microbial regime as well as subtle variations in rank.Pristane/phytane, dibenzothiophene/phenanthrene and thiophene ratios are closely related ++ / to organic sulphur contents, but are also influenced by these changes in rank and differences in the timing of marine incursion.Organic sulphur contents and biomarker compositions are related through a drillcore profile, which confirms the role of diagenetic sulphur sequestration in preserving specific biomarkers (steranes, higher plant triterpanes, extended hopanes) in coal-forming environments. Biomarker ratios that vary accordingly include the homohopane index, Ts/Tm, C29Ts/norhopane, C30 diahopane/hopane, sterane/hopane ratio, C29 diasterane/sterane, oleanane/hopane, oleanoid triterpane/hopane, and ring A degraded triterpanes/des-E-hopane.Diasterane concentrations were greatest in high sulphur coals. It is suggested that sterenes, generated from sulphur-bound steroids of regular stereochemistry in the subsurface, undergo acid-catalysed rearrangement and hydrogenation to enhance diasterane concentrations. A similar formation mechanism can be invoked for the rearranged hopanes (Ts, C29Ts, C30 diahopane) and oleanoid triterpanes. The timing of sulphur fixation does not appear to have influenced the formation of biomarkers except in one case. The only lipid class that degraded rapidly enough for the precursors required for sulphurisation to be removed prior to saline access is the higher plant triterpenoids. Stable carbon isotopic analysis of the n-alkanes, isoprenoids and hopanoids from the Pike River Outcrop seam section confirms both higher plant and microbial sources. In particular, the carbon isotopic composition of phytane suggests that methanogenic decomposition of the Pike River peat occurred. The isotopic signatures are invariant to changes in the degree or timing (Class A-C only) of sulphur access to this outcrop.This body of work finds that the introduction of marine waters (and the formation of reduced sulphides) in the early stages of mire and peat ++ / development preserves the inherited lipid composition of the peat and does not overwhelm this biotic signature during sulphate reduction. As such, the selective preservation of certain biomarkers enables their use as indicators of marine-influence in source rocks. The application of several biomarker ratios to the characterisation of crude oils from the Taranaki Basin of New Zealand provides further evidence for the generation of liquid hydrocarbons from marine-influenced, angiosperm-rich coals.

The plasticity of coal during pyrolysis is of significant importance, since it affects the reactivity, porosity, particle size and the density of the char and thus also the behaviour of the char during further utilisation processes. The main focus of this study was to characterize the chemical and physical changes which the thermally treated coal undergoes, in order to better understand the pyrolysis process of caking and non-caking South African coals. The pyrolysis behaviour of three South African coals with different caking indices was investigated. The coal samples included; (1) Highveld (TWD), a medium rank C coal with a free swelling index (FSI) of 0, (2) Grootegeluk (GG), also a medium rank C coal, with a FSI of 6.5, and (3) Tshikondeni (TSH), a medium rank B coal with the highest FSI of 9. The three coal samples were classified as vitrinite-rich coals consisting of mainly aliphatic structures. Thermogravimetric experiments were used to determine the different temperatures relating to specific percentages of mass loss using set conditions. The pyrolysis process was stopped at various percentages of mass loss (thus at various stages of the reactions) to characterize the chemical structural changes that occurred at the specific mass loss percentages. The results obtained from characterization analyses indicated that the three coals differ in chemical composition and thus were expected to behave differently during pyrolysis. The coal samples consist of different amounts of macerals and minerals according to X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) analyses. The Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) results indicated that some of the functional groups within the coal samples evolved with the increase in temperature. The highly caking coal (TSH) exhibited the highest aromaticity and ring condensation. The surface areas were determined by CO2 adsorption and an increase in surface area was observed with an increase in temperature. The surface area of the GG and TSH coal-derived char samples decreased at some stage, which is an indication of thermoplastic behaviour and subsequent swelling of the coal samples. Scanning electron microscopy (SEM) images confirm the plastic stage of caking coals at specific temperatures and volatile matter release via the multiple bubble mechanism. All these results are given and discussed extensively in this dissertation. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2015

The plasticity of coal during pyrolysis is of significant importance, since it affects the reactivity, porosity, particle size and the density of the char and thus also the behaviour of the char during further utilisation processes. The main focus of this study was to characterize the chemical and physical changes which the thermally treated coal undergoes, in order to better understand the pyrolysis process of caking and non-caking South African coals. The pyrolysis behaviour of three South African coals with different caking indices was investigated. The coal samples included; (1) Highveld (TWD), a medium rank C coal with a free swelling index (FSI) of 0, (2) Grootegeluk (GG), also a medium rank C coal, with a FSI of 6.5, and (3) Tshikondeni (TSH), a medium rank B coal with the highest FSI of 9. The three coal samples were classified as vitrinite-rich coals consisting of mainly aliphatic structures. Thermogravimetric experiments were used to determine the different temperatures relating to specific percentages of mass loss using set conditions. The pyrolysis process was stopped at various percentages of mass loss (thus at various stages of the reactions) to characterize the chemical structural changes that occurred at the specific mass loss percentages. The results obtained from characterization analyses indicated that the three coals differ in chemical composition and thus were expected to behave differently during pyrolysis. The coal samples consist of different amounts of macerals and minerals according to X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) analyses. The Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) results indicated that some of the functional groups within the coal samples evolved with the increase in temperature. The highly caking coal (TSH) exhibited the highest aromaticity and ring condensation. The surface areas were determined by CO2 adsorption and an increase in surface area was observed with an increase in temperature. The surface area of the GG and TSH coal-derived char samples decreased at some stage, which is an indication of thermoplastic behaviour and subsequent swelling of the coal samples. Scanning electron microscopy (SEM) images confirm the plastic stage of caking coals at specific temperatures and volatile matter release via the multiple bubble mechanism. All these results are given and discussed extensively in this dissertation. / MSc (Chemistry), North-West University, Potchefstroom Campus, 2015

This serves to introduce the present research and is chiefly historical. It deals briefly with methods of assessing the coking ability of coals and also with early modern, and contemporary investigations upon coke formation. The author's earlier work on the distillation of oil from coals is described fully since it forms both the starting point and the basis of the present research. This work showed the power of retention of oil which is capable of 'wetting' the surface of the coal, up to temperatures of 420 degrees C., was an essential characteristic of coking coals. Part II deals with attempts to add more oil mechanically to improve the coking performance of various coals.

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / A 2002 report by Australian National Greenhouse Gas Inventory suggests that since 1990 Australia's net emissions of carbon dioxide equivalent from stationary combustion sources are on the rise and they are likely to rise even at a higher rate in keeping with continued economic and industrial growth. In order to reduce Australian CO₂emissions, there is a need to identify and explore large-capacity storage locations for CO₂ sequestration. In that context, Australian coal seams, notably the coal-bed methane (CBM) reservoirs in Sydney and Bowen Basins, could potentially be attractive sites to sequester large volumes of greenhouse CO₂ emissions while also recovering the methane gas, a relatively cleaner source of fossil fuel. This study investigates the deliverability and economic feasibility of CO₂ sequestration through CO₂-Enhanced CBM recovery (CO₂-ECBMR) in the Camden area, Sydney coal basin. The results of the study show that the CO₂-ECBMR impacts the absolute pelmeability of the Camden area significantly. Because of a good reticulated fracture system, the CO₂ breakthrough from the producers is faster. The enhancement of CH₄ recovery by preferential adsorption of CO₂ occurs simultaneously with the abatement of CH₄ recovery by overall decrease in permeability in the CBM reservoir. Hence, the actual CH₄ is produced under the overall effect of these two competing processes, with the operating parameters like producer-injector spacing and injection pressure affecting their relative dominance over each other. The study also addresses the opportunities of a niche for CO₂ sequestration in these coals, which will be dictated mainly by the factors of sequestration economics and status of these coals being "unmineable". The results derived from the study could help the design of an optimum operating strategy in implementing the CO₂ sequestration and enhanced CBM recovery in Sydney Basin, Australia and elsewhere. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1259968 / Thesis (Ph.D.) -- University of Adelaide, Australian School of Petroleum, 2006

Title page, abstract and table of contents only. The complete thesis in print form is available from the University of Adelaide Library. / A 2002 report by Australian National Greenhouse Gas Inventory suggests that since 1990 Australia's net emissions of carbon dioxide equivalent from stationary combustion sources are on the rise and they are likely to rise even at a higher rate in keeping with continued economic and industrial growth. In order to reduce Australian CO₂emissions, there is a need to identify and explore large-capacity storage locations for CO₂ sequestration. In that context, Australian coal seams, notably the coal-bed methane (CBM) reservoirs in Sydney and Bowen Basins, could potentially be attractive sites to sequester large volumes of greenhouse CO₂ emissions while also recovering the methane gas, a relatively cleaner source of fossil fuel. This study investigates the deliverability and economic feasibility of CO₂ sequestration through CO₂-Enhanced CBM recovery (CO₂-ECBMR) in the Camden area, Sydney coal basin. The results of the study show that the CO₂-ECBMR impacts the absolute pelmeability of the Camden area significantly. Because of a good reticulated fracture system, the CO₂ breakthrough from the producers is faster. The enhancement of CH₄ recovery by preferential adsorption of CO₂ occurs simultaneously with the abatement of CH₄ recovery by overall decrease in permeability in the CBM reservoir. Hence, the actual CH₄ is produced under the overall effect of these two competing processes, with the operating parameters like producer-injector spacing and injection pressure affecting their relative dominance over each other. The study also addresses the opportunities of a niche for CO₂ sequestration in these coals, which will be dictated mainly by the factors of sequestration economics and status of these coals being "unmineable". The results derived from the study could help the design of an optimum operating strategy in implementing the CO₂ sequestration and enhanced CBM recovery in Sydney Basin, Australia and elsewhere. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1259968 / Thesis (Ph.D.) -- University of Adelaide, Australian School of Petroleum, 2006

South Africa remains the 5th largest producer and 4th largest exporter of coal in the world. It is also the largest supplier of coal to the European Union. This fact is significant as the European Union has recently supported the environmental lobby that threatens the combined full scale use of coal in Europe and other first world countries. This promotes the development of clean coal technologies in order to counter the ever increasing number of environmental constraints threatening the export market. One critical development in clean coal technologies is coal beneficiation, which allows the reduction of ash and inert content. Permian coals from South Africa have characteristically high ash and inertinite contents and therefore require further beneficiation. The Witbank coalfield No. 4 seam is no exception. It can be described as being more inert and having a higher mineral content compared to the No. 2 seam in the same coalfield also mined for export purposes. With the increase in environmental legislation and the push towards “clean coal” this raises a concern in terms of the performance and marketability of export coal produced from the No. 4 seam. This seam will in the future be economically significant and is still a great source for export steam coal. Due to the nature and composition of the No. 4 seam, coal beneficiation is essential to reduce the mineral and inert content to be in line with export quality specification levels. Washability characteristics of the No. 4 seam coal indicate that the No. 4 seam is difficult to beneficiate. Until recently the main clean-ability parameters evaluated in South African export coals as per customer specification included mainly heating value, moisture and ash reduction with little to no work being done on trace element concentration reduction. This paper focuses on the partitioning of the trace elements within the seam in relation to the organic and inorganic affinity of the trace elements and possible methods of trace element reduction by removal using coal beneficiation techniques. The techniques investigated include reduction by washing using dense medium beneficiation and flotation. In each evaluation the focus was on trace-element-tomineral and trace-element-to-organic matter relationship and hence setting the basis for liberation analysis to evaluate reducibility. By the evaluation of the coal mineralogy, petrography and trace element relationships, methods of optimum trace element reduction can be established. With the focus on marketing it was shown that carbon loss need not be sacrificed in the reduction of specific trace elements in the No. 4 seam and that the trace element distribution itself allows for beneficiation whilst maintaining acceptable yields. Processes and possible beneficiation techniques for optimum trace element reduction and marketability in the case of the No.4 seam are proposed.

Coal is a chemical compound with a complex composition. Proximate and ultimate analysis as well as physical and mechanical tests which are available do not furnish all the information required by industry. Information regarding e.g. the burning properties of coal is required by furnace and boiler designers. Thermal analysis can be used for studying these properties using small masses of coal. Differential thermal analysis (DTA) where temperature variations are measured which result from reactions which occur when coal is heated and thermogravimetric analysis, (TGA) where similarly mass variations are measured, are regarded as important. Results from eg. TGA tests are usually interpreted without unified and formally accepted prescripts. It is desirable to investigate how the best use can be made of thermal analysis of coal, using DTA and TGA, and to devise a procedure for interpreting the results. The problem is approached by studying DTA and TGA results obtained from a specially selected group of coals for which other analytic data are available. The samples were prepared according to the standard procedure for the laboratory analysis of coal. At first, related information published by other researchers were integrated and parameters used by them identified and assessed in terms of fundamental scientific principles. Special experiments were conducted to probe the situation regarding orthodox kinetics of reactions and its related theory and observed discrepancies with regard to coal and its decomposition characteristics. It was found, along with other observers, that eg. activation energy values which are derived from TGA data should be used with extreme caution. In general an empirical approach for interpretation of results has much to offer. A system is developed by which various thermal techniques, executable by a single instrumental arrangement can be identified by expressing them in matrix format using as indexes, heating arrangement, reactant type and reaction environment. 5(1,1,2) e.g. designates a linearly heated mass of coal in air at atmospheric pressure. To enhance the comparison of TG characteristics of similar coals they should be classified according to a matrix arrangement C(g,t,r) which is based on three index parameters namely, grade ie. the ash content, type ie. the vitrinite content and rank. A TG test provides the basic requirements for computing the indexes using formulae provided by the originators. Information which can only be derived from a TG experiment e.g. 5(1,1,2), are referred to as specification parameters. The information consists of e.g. a series of temperatures which identify specific reaction changes in the coal. Several other parameters can be derived. Coals are assessed by comparing their specification parameters. Only two of the S(i,j,k) techniques are described in detail namely TG dispersion 5(1,1,2) and drop furnace burnout 5(3,1,2). The dispersion technique requires a linear increasing furnace temperature while the near sample temperature is also measured. This technique shows the decomposition stages of coal from dehydration to complete burnout. The drop furnace technique, involves a sudden exposure of the coal to a hot furnace environment with free air access: Actual burnout of coal is emulated. The model is not perfect for combustion but the best that can conveniently be acquired for comparing the burning responses of coals. To illustrate the type of information which can be obtained with other S(i,j,k) techniques experimental results of eg. a devolatilization test are presented. Brief reference is made to the role that particle size plays during combustion and the importance of the composition of volatiles which are released is indicated by presenting relevant information from external sources. The chemical composition and structure of the coals could not be determined but relevant information from an external source was presented which has a bearing on the practical analytic procedure which was described. After a study of the group TG characteristics of the various coals and discussion of the conclusions which are justified a practical procedure is described according to which the equipment can be used both for routine or special purpose analysis of coal. / Thesis (PhD)--University of Pretoria, 2013. / Geology / unrestricted