Australian Oil Research Articles

Kinetics of coking shale oil vapour on combusted spent shale for eight Australian oil shale deposits

Data are presented on the kinetics of coking at 500 °C of shale oil vapours on combusted spent shale (shale ash) prepared from samples of oil shales from the Condor, Duaringa, Lowmead, Nagoorin, Nagoorin South, Rundle, Stuart and Yaamba deposits. The results are correlated in an equation that gives the yields of carbon deposited on the shale ash as a function of reaction time and oil vapour concentration. Reaction coefficients that characterize the reactivities of the oils and ashes are given. Additional data that relate the yields of carbon to the other reaction products are also presented. On the bases of these data, recommendations are made for the selection of retort operating conditions to minimize oil yield losses due to coking.

Rapid analysis of oil shales for oil yield using X-ray spectrometry

A close correlation was found between the scattering of X-rays (the Rayleigh:Compton ratio) and oil yield as given by Fischer assay for a number of Tertiary Australian oil shales. Based on this relationship, a rapid laboratory procedure was developed, using an X-ray spectrometer, which should be useful in the control of mining and processing of oil shale deposits.

THE OIL AND GAS LABOUR MARKET — AN OVERVIEW

Over the past four years the Australian Oil and Gas Exploration Industry has moved from a period of high exploration and development, skill shortages and overseas recruitment, through to a period of declining levels of exploration activity and expenditure, low world prices and significant retrenchments.A number of manpower and training aspects of industry development and decline over the period 1980 through to 1987 are discussed.The paper reviews and examines aspects of the Australian oil and gas work force and labour market. It brings into sharp focus a number of critical training and professional development issues facing the industry today. It proposes a review and rationalisation of academic programs for geoscientists and planning for future manpower requirements for the industry.

AUSTRALIAN BROWN COAL/OIL MIXTURES AS A FUEL FOR DIESEL ENGINES; ENGINE PERFORMANCE AND ECONOMIC VIABILITY

ABSTRACT CSIRO Division of Energy Technology has used mixtures of finely ground, chemically beneficiated, Australian brown coal (up to 30% by weight, maximum particle size less than 13 microns) and automotive diesel oil (ADO) to fuel an essentially unmodified single cylinder diesel engine operating at 800, 1200 and 1500 r/min. Engine performance tests indicate that brown coal can be used as a fuel extender to reduce consumption of the conventional liquid diesel fuel (ADO). Partially burnt coal agglomerates were identified in the engine exhaust and there were indications of late burning at the higher engine speeds and coal concentrations. Engine brake thermal efficiency ratio is identified as an important parameter when evaluating the thermal performance and economic viability of new fuels for internal combustion engines. A simple economic model based on ‘payback period’ is developed and used to assess the viability of converting an existing diesel engine powered plant to operate on the coal/oil mixture fu...

On the viability of A gas-to-gasoline industry in Australia

The linear programming, energy systems analysis model, MARKAL, was used to examine the impact on the Australian energy system of a Mobil process, gas-to-gasoline plant producing up to 100 PJ/a of high octane gasoline from the year 2000. The total capital cost of the plant, including the drilling platform and shore-based infrastructure, was estimated to be 4100 MSA (1982). The costs and benefits of introducing this technology were calculated for high, medium and low assumptions on indigenous oil discovery rates, imported oil prices and overall demand levels. The effect on the Australian oil refinery sector was also briefly addressed. Under the assumptions presented to the model, a sufficient requirement for a gas-to-gasoline plant to offer a net benefit to the overall energy system is for the real price of crude oil to increase by 50 per cent by the year 2025. Even so, if the plant were introduced in the year 2000, it could not achieve the minimum desired return on investment. If the introduction were delayed for five years the prospects would improve considerably, but there would still be a less than 30 per cent chance of exceeding a 7.5 per cent real return on capital invested. Considerable government guarantees would be necessary to underpin what would appear, from present knowledge, to be a fairly risky investment proposition.

The yield of Australian oil shales as determined by nuclear magnetic resonance and infrared spectroscopy

A suite of oil shales which varied considerably both in type and Fischer assay yield were examined by infrared (i.r.) and nuclear magnetic resonance (n.m.r.) spectroscopy. Plots were constructed of the area of the aliphatic C-H stretching bands in the i.r. spectrum against the Fischer assay yield and also the per cent aliphatic carbon as determined by n.m.r. against yield. As expected from earlier studies, both gave correlations, but it was evident that the n.m.r. results gave a more accurate prediction of oil yield than did the i.r. data.

Pyrolysis and hydropyrolysis of two carbonaceous Australian oil shales in supercritical toluene and tetralin

Two carbonaceous Australian oil shales from the Yaamba and Nagoorin deposits have been pyrolysed in a batch micro-autoclave tubing bomb reactor at a heating rate of ≈ 1000 K min −1. The shale samples were pyrolysed under reactive (hydrogen) and non-reactive (helium) gases, and in the presence and absence of an added reactive or non-reactive fluid phase consisting of either tetralin or toluene. Limited screening of the effect of impregnated molybdenum and platinum catalysts has also been carried out. Experiments were conducted at 450 °C and ≈ 15.2 MPa, at which conditions the added liquids were present in the reactor as supercritical fluids. Data on organic carbon conversion to oil plus gas have been obtained for residence times ranging from 2 to 30 min. Application of rapid heating under helium coupled with the presence of a non-reactive supercritical fluid phase (toluene) enhances carbon conversion to oil plus gas relative to rapid pyrolysis in the absence of supercritical toluene. Hydrogen gas in the presence of supercritical toluene is effective in increasing yields even further for the more aromatic shale, while the effect of hydrogen partial pressure is minimal for the aliphatic shale. Use of a hydrogen transfer agent as the supercritical fluid greatly enhances organic carbon conversion with yields of over 1100% of Fischer Assay achieved for the aromatic (Yaamba) oil shale. Application of impregnated molybdenum and platinum catalysts also enhances carbon conversion and oil yield, but only at elevated hydrogen partial pressures.

Predictor-corrector numerical methods for kinetic analysis of TG data: methods applied to oil shale pyrolysis

Numerical methods were adapted for the direct solution of non-isothermal kinetic equations, and their use was illustrated by their application to the thermogravimetry of oil shale pyrolysis. Software packages were assembled for numerical integration using a predictor-corrector method, for graphical screen display of theoretical and experimental TG and DTG curves, and for refinement of kinetic parameters by non-linear regression. Experimental TG-DTG profiles were obtained for kerogen concentrates of two Australian oil shales, one being a torbanite from the historical deposit of Hartley Vale in New South Wales, and the other a brown shale from the Condor deposit in Queensland. No single kinetic model could be fitted to the experimental data, but functions based on multistage models gave excellent agreement between calculated and experimental TG-DTG profiles.

Kinetics of production of individual products from the isothermal pyrolysis of seven Australian oil shales

Data are presented on the kinetics of production of oil and gaseous products from the isothermal pyrolysis of samples of Queensland oil shales from the Condor, Duaringa, Lowmead, Nagoorin, Nagoorin South, Rundle and Stuart deposits. The results are correlated in equations which give the yields of the various products as functions of the time and temperature of pyrolysis. Similarities and differences in the pyrolysis kinetics of the seven oil shales are discussed. The method is also attractive as a material balance assaying procedure. Comparison with Fischer assay results shows that the method gives yield data with a reproducibility and material balance closure at least equal to the Fischer assay; it is also a much faster method of analysis and requires < 1 g of sample.

The pyrolysis kinetics of some Australian oil shales

The kinetics of hydrocarbon evolution from the pyrolysis of Rundle and Nagoorin shales can be described by two simultaneous first order rate laws whose relative contributions depend on the pyrolysis temperature. At low temperatures, a relatively rapid release of low molecular weight products occurs followed by a slower formation of higher molecular weight products. At high temperatures, secondary cracking reactions, resulting in the formation of low molecular weight aromatics, contribute to the total hydrocarbon release, and oil evaporation is kinetically important. The major constituents of the oil (alkanes, alkenes, aromatics) are formed at significantly different rates and according to different rate laws. The pyrolysis of Condor shale shows a marked particle size dependence, which cannot be described by any simple kinetic model, and is probably dominated by mass transfer effects.

Petrographic approach to beneficiation of Australian oil shales

Australia has five types of oil shales, cannel coal, torbanite, lamosite, tasmanite and marinite, each of which has a different organic composition. Cannel coal is composed of liptinite (mostly resinite, cutinite and sporinite) derived from terrestrial plants, vitrinite and inertinite, with only a small amount of mineral matter. Torbanite is composed of large telalginite, derived from Botryococcus and related algae, in a groundmass of vitrinite and inertinite. It is difficult to crush and petrographic analysis indicates that beneficiation would be difficult. Lamosite contains abundant lamalginite, derived from freshwater, planktonic algae, with minor vitrinite and telalginite; petrographic analysis confirms that comminution produces alginite-poor fines and a higher grade concentrate. Marinite is a relatively low grade oil shale composed of lamalginite and bituminite, both of which are unlikely to be easily separated from the mineral groundmass. Tasmanite is composed of telalginite, derived from marine precursors, which is easily separated from the mineral matter when the oil shale is crushed.

Near-Infrared Photoacoustic Spectroscopy of Coals and Shales

Recently Fresh et al. studied, reportedly for the first time, the near-infrared (NIR) spectra of a number of coking coals using a diffuse reflectance technique, although these workers noted that this technique could have significant disadvantages when used to examine coal. Photoacoustic spectroscopy (PAS) is an alternative technique for examining solid samples, with the advantage over other methods of easier sample preparation. PAS has been used to examine coal samples but only in the mid-IR region. In this PAS study, a number of Australian coals of widely varying rank and various Australian oil shales were examined in the NIR.

Mineral separation techniques for inorganic constituents in some Australian oil shales

Mineral separation techniques for inorganic constituents in some Australian oil shales

The isotopic composition of nitrogen in Australian coals and oil shales

The Kjeldahl method for the quantitative determination of nitrogen in coal is unsuitable for the preparation of nitrogen for isotopic analysis. Consequently, a modified Dumas method was developed which allowed δ 15 N-values to be determined in coals and oil shales with a precision greater than ± 0.3%‰. Comparison of nitrogen contents obtained by the Dumas and Kjeldahl methods showed that there was little difference for oil shale samples but that for coals the results obtained with the Dumas method were higher, the difference increasing with increasing nitrogen content of the sample. This suggests that the poor reproducibility of isotopic data when using the Kjeldahl method results from loss of nitrogen during sample preparation. 15 N 14 N ratios in Australian coals fall within the narrow range reported by other authors for North American and European colas and do not correlate with either the age, rank or depositional environment of the coal. The 15 N content of the oil shales varies according to predominant organic precursors, the concentration and source of the nitrogen (molecular, ammonia, nitrate) and the pathways utilized during metabolism. The different types of Australian oil shales can be classified by nitrogen isotope ratio analysis which, in general, supports a classification based primarily on microscopic techniques.

The isotopic composition of nitrogen in Australian coals and oil shales

The Kjeldahl method for the quantitative determination of nitrogen in coal is unsuitable for the preparation of nitrogen for isotopic analysis. Consequently, a modified Dumas method was developed which allowed δ 15N-values to be determined in coals and oil shales with a precision greater than ± 0.3%‰. Comparison of nitrogen contents obtained by the Dumas and Kjeldahl methods showed that there was little difference for oil shale samples but that for coals the results obtained with the Dumas method were higher, the difference increasing with increasing nitrogen content of the sample. This suggests that the poor reproducibility of isotopic data when using the Kjeldahl method results from loss of nitrogen during sample preparation. 15 N 14 N ratios in Australian coals fall within the narrow range reported by other authors for North American and European colas and do not correlate with either the age, rank or depositional environment of the coal. The 15N content of the oil shales varies according to predominant organic precursors, the concentration and source of the nitrogen (molecular, ammonia, nitrate) and the pathways utilized during metabolism. The different types of Australian oil shales can be classified by nitrogen isotope ratio analysis which, in general, supports a classification based primarily on microscopic techniques.

Classification of Australian Oil Shales

Oil shales, a possible additional source of liquid hydrocarbons for Australia, contain abundant organic matter that is best described using coal maceral terminology. Liptinite is the dominant maceral in all the oil shales and the type and abundance of liptinite is used to divide the oil shales into cannel coal, torbanite, lamosite, marinite and tasminite. The oil shales are formed in lakes associated with peat swamps, fresh to brackish water lakes and shallow oceans. The present status of each of the five types of Australian oil shales is reviewed.

Identification and treatability of organics in oil shale retort water

Analysis by GC-MS of the process water derived from Fischer Assay retoring of oil shale from Rundle, Australia has provided positive identification of the major organic constituents present. This is the first detailed analysis of retort water from Australian oil shales and showed that the compounds ranged from being highly biodegradable to highly inhibitory and resistant to biological oxidation. The major classes of compounds found in a composited sample included normal carboxylic acids, alkyl pyridines, quinolines and cyclic saturated and unsaturated ketones. Separation of the retort water into its acid, base and neutral fractions was brought about by solvent extraction using methylene chloride. A series of treatability studies on the retort water confirmed the hypothesis that only a portion of the organic carbon was amenable to biological treatment. In addition, high ammonia levels further inhibited biological action. Adsorption of the retort water with activated carbon proved most successful in removing the non-biodegradable fraction of the organic species. Chemical oxidation by ozone does not appear attractive because it lacks the specificity of adsorption.

Trace element partitioning during the retorting of some Australian oil shales

La comparaison de la mobilite des elements montre la variabilite dans le degre de separation pour chacun des echantillons durant la distillation

Modelling of spent shale gasification

A model describing the gasification of a spent shale particle in an atmosphere of steam, hydrogen, carbon monoxide and methane is developed. Both diffusion and reaction rate terms are included. Simulations on spent Australian oil shale show that the external mass transfer coefficient has no effect on the overall gasification rate. Increasing the temperature above 1500 K does not increase the gasification rate significantly. No methane was produced under the conditions of the study. The simulations show that neither the homogeneous reaction model nor the shrinking-core model applies for the expected range of operating conditions. Effects of temperature, pressure, particle size and the ratio of carbon dioxide to steam on the conversion and yield are discussed in this paper.

The application of simultaneous DTA and TG to some aspects of oil shale mineralogy

The mineralogy of most Australian oil shales is relatively simple and belongs to the carbonate, clay, sulphide, sulphate, silica, phosphate, zeolite and evaporite/saline mineral groups. Retorting involves heating during which virtually all oil shale minerals react. Such reactions, endothermic or exothermic may be characterised and measured by DTA, whilst associated weight variations may be continuously quantified by TG. These methods provide mineralogical identification and evaluation data, together with reaction type, magnitude and heat balance information, obtained under heating rate and gas atmosphere conditions preselectable to simulate various retorting conditions. Endothermic and exothermic mineral reactions taking place within the retort may strongly influence the required retort heat balance regime. Detailed knowledge of the actual minerals present, their quantities, reaction temperatures and types, together with heat balance effects are of marked technological importance to the design and operation of oil shale retorts and the assessment of spent shale characteristics and potential utilisation.