Fossil Hydrocarbons Research Articles

Mechanism of formation and chemical structure of Coorongite—II. Structure and origin of the labile fraction. Fate of botryococcenes during early diagenesis

A sample of Coorongite derived from botryococcene-producing Botryococcus braunii was examined. The analysis of the bitumen indicated a contamination by fossil hydrocarbons. However, the products released on pyrolysis of the bitumen-free Coorongite are not affected by this contamination. Selectively preserved resistant biopolymer (PRB B) is a major constituent of the Coorongite and the 400°C pyrolysate entirely consists of the cracking products of this resistant material (Dubreuil et al., Org. Geochem., submitted, 1988). In addition to PRB B, the bitumen-free Coorongite is composed of chemically and thermally labile constituents that are released during pyrolysis at 300°C. A principal structural feature of this labile fraction is terminal CH 2CHR unsaturations. The labile fraction of Coorongite is not derived from botryococcenes and the bulk of this fraction is probably of bacterial origin. In fact no traces of botryococcenes, or of derived products, were detected either in the 300°C pyrolysate or in the bitumen and in the 400°C pyrolysate. Early diagenesis under oxic conditions results in a complete degradation of the large amount of botryococcenes present in the initial biomass. This quite low resistance of botryococcenes is an agreement with: (1) the lack of botryococcane in the bitumen of Torbanites, even when deposited under partly oxic conditions; (2) the presence of botryococcane in a very limited number of oils and bitumens in spite of the widespread occurrence of Botryococcus remains in numerous kerogens.

Petrochemicals: the chemistry of catalyzed air oxidation of fossil hydrocarbons

The reaction mechanisms and the selective products formed during the air oxidation of some important industrial paraffins and arenes catalysed homogeneously by transition metal complexes such as Cu(I), Co(II), and Mn(II) are discussed. In addition, the main uses of the major products generated from these catalytic air oxidation processes are summarized.

THE USE OF PLANT DERIVED BIOMARKERS FOR CORRELATION OF OILS WITH SOURCE ROCKS IN THE COOPER/EROMANGA BASIN SYSTEM, AUSTRALIA

Whether or not the sediments in the Eromanga Basin have generated petroleum is a problem of considerable commercial importance which remains contentious as it has not yet been resolved unequivocally. Sediments of the underlying Cooper Basin were deposited throughout the Permian and much of the Triassic, and deposition in the overlying Eromanga Basin commenced in the Early Jurassic and extended into the Cretaceous. As Araucariaceae (trees of the kauri pine group) assumed prominence for the first time in the Early to Middle Jurassic and were all but absent in older sediments, a promising approach would seem to be using the presence or absence of specific araucariacean chemical marker signatures as a means of distinguishing oils formed from source rocks in the Eromanga Basin from those derived from the underlying Cooper Basin sediments.The saturated and aromatic hydrocarbon compositions of the sediment extracts from the Cooper and Eromanga Basins have been examined to identify the distinctive fossil hydrocarbon markers derived from such resins. Sediments from the Eromanga Basin, which contain abundant micro-fossil remains of the araucariacean plants, contain diterpane hydrocarbons and aromatic hydrocarbons which bear a strong relationship to natural products in modern members of the Araucariaceae. Sediments from the Permo-Triassic Cooper Basin, which predate the Jurassic araucariacean flora, have different distributions of diterpane biomarkers and aromatic hydrocarbons.Many oils found in the Cooper/Eromanga region do not have the biological marker signatures of the Jurassic sediments and appear to be derived from the underlying Permian sediments; however, several oils contained in Jurassic to Cretaceous reservoirs show the araucariacean signature of the associated Jurassic to Early Cretaceous source rock sediments. It is likely, therefore, that these oils were sourced and reservoired within the Eromanga Basin and have not migrated from the Cooper Basin sequences below. Accordingly, exploration strategies in the Cooper Eromanga system should include prospects that could have been charged with oil from mature Jurassic/Early Cretaceous sediments of the Eromanga Basin.

MECHANICAL AND DIELECTRIC LOSS SPECTRA OF AMBERS

Amber is a fossilized resin with a molecular structure similar to that of other fossil hydrocarbons. It displays internal friction peaks similar to those of synthetic polymers and other macromolecular hydrocarbon materials. It is an excellent dielectric, and has a dielectric loss spectrum as well. We have utilized internal friction and dielectric loss spectra to elucidate some features of ambers from different geological periods.

木材の接触液化技術

Direct liquefaction of wood by thermochemical conversion as well as biochemical conversion has been attracting attention with the depletion of fossil hydrocarbons. In this paper, the history of wood liquefaction is briefly reviewed, and the chemistry and technology of wood liquefaction are discussed. The PERC process, LBL process and a new process of liquefaction using no reducing agents like hydrogen and/or carbon monoxide are introduced.

Economics and potential application of electrolytic hydrogen in the next decades

Abstract The demand for hydrogen will increase within the next decades mainly due to the necessity of producing clean and environmentally accepted fuels from fossil hydrocarbon resources of minor quality and from coal. The use of electrolytic hydrogen is limited by the economics of its production which is dominated by the cost of the electrical energy necessary for water splitting. The potential for cost reductions by the application of new electrolysis technologies is investigated and break-even electricity prices are calculated at which electrolytic hydrogen can compete with hydrogen produced from fossil fuels. Although in general electrolytic hydrogen production is not yet competitive, there are good prospects for advanced, highly efficient processes (e.g. the electrolysis of steam) to be developed within the next decades. Small and medium hydrogen production plants of this type might be competitive soon, and they are attractive if the oxygen by-product and the environmental advantages are taken into account.

Gas chromatography/mass spectrometry of degraded triterpanes in fossil organic matter - a record of microbial action

Homologous and isomeric pentacyclic triterpanes originating from biogenic hopanoids are ubiquitous geochemical fossils in sediments and crude oils. Their characteristic mass spectrometric fragmentation pattern allowing their detection even in trace quantities in complex fossil hydrocarbon mixtures, led to their application in petroleum exploration by monitoring the m/z 191 key fragment. Demethylation of hopanes occurs during microbial degradation of crude oils in the reservoir. The mass spectrometric key fragment of these 25-norhopanes is shifted to m/z 177 and the relative abundance of the major fragments changed. Other nuclear-demethylated hopanes formed by early diagenetic microbial alteration of biogenic precursors are found in high concentration in immature sediments.

Organic resources of the sea

Despite the vast number of phyla and species in the sea, the major marine resource will continue to be fish for hum an consumption. At the same time, research on methods of preparing an animal protein concentrate, of high nutritional value and acceptable as human food, has pointed the way for the eventual development of a new technology. Other bulk products of marine life-forms have been suggested as organic resources and include specific fatty acids and prostaglandins as therapeutic agents in human medicine as well as fatty alcohols and invertebrate chitin for industrial purposes. Only a few of the many options are considered here since the product must compete in terms of special properties, cost and availability with those derived from biomass of the land, industrial microbiology and from synthetic products made from fossil hydrocarbons. Many biologically active chemicals have been isolated from marine life-forms, but only a few have been used as systemic drugs and selectively toxic agents (antibiotics) in human medicine. These and other chemicals that accumulate in marine organisms would illustrate that species survival in marine ecosystems have evolved specialized metabolic mechanisms that differ from those of terrestrial life-forms. Progress has been slow but it is with the nature and exploitation of these differences that future marine biological and biochemical research and development should be concerned.

Flux of aliphatic and polycyclic aromatic hydrocarbons to central Puget Sound from Seattle (Westpoint) primary sewage effluent

Concentrations and mass emission rates are reported for hydrocarbons in a 20-month evaluation of primary municipal waste water discharging to marine waters of Puget Sound from Seattle, WA. On the average, METRO (Westpoint) discharges 475 metric tons/year of aliphatic hydrocarbons and approximately 1 metric ton/year of 3-7 ring polynuclear aromatic hydrocarbons (PAH), corresponding to discharges of 2.6 and 0.005 g/(capita day), respectively. Effluent PAH containing greater than or equal to 4 rings apparently derive principally from storm-water contributions. A comparison of METRO's yearly average discharge of different hydrocarbon components with observed hydrocarbon fluxes in adjacent Puget Sound surface sediments suggests negligible accumulations of the resolvable alkanes (derived from the effluent), partial accumulations of an unresolved complex mixture and phenanthrene, and substantial accumulations of the greater than or equal to4-ring PAH. The discharge accounts for a major portion of the sedimentary aliphatic fossil hydrocarbon flux and is one of several important PAH contributors. 45 references, 2 figures, 5 tables.

Aliphatic hydrocarbons in particulate matter from the Baltic Sea

During May 1980, particulate matter was collected at an anchor station from different depths by two methods. In the separated hydrocarbon fraction the most abundant component was the highly unsaturated hydrocarbon n-heneicosahexaene (HEH). Also present was a series of mono- and di-unsaturated olefinic hydrocarbons with an uneven number of carbon atoms, starting with n-C 17. The alkane pattern was characterized by a maximum in the range between n-pentadecane and n-heptadecane, with a strong uneven to even carbon number predominance. The peculiar composition of the aliphatic hydrocarbons was compared with literature data given for aliphatic hydrocarbons, whether produced by different marine organisms or derived from crude oil of other anthropogenic sources. A suggestion is made for using a set of conditions as indicators for pollution by fossil hydrocarbons.

Organic substances in the Baltic Sea

In view of the potentially very large number of organic pollutants which are likely to enter the Baltic Sea via land run-off, precipitation, from ships, or as a result of past and present dumping, the number of organic substances actually measured on a scale sufficiently large for an overall assessment is rather small. These substances are: mineral oil, chlorinated hydrocarbon pesticides, polychlorinated biphenyls. It is recognized, of course, that these substances, especially in the case of mineral oil, consist of a multitude of individual chemical components, but this is not the point. Rather there may be many more chemically quite different organic substances with potentially harmful effects present in the Baltic Sea which are measured only occasionally, such as phthalate ester plasticizers 0Ehrhardt & Derenbach, 1980); others whose existence is known, but which are not measured in the Baltic, such as halogenated paraffins (Jernel0v et al., 1972); and still others which have not yet been detected in seawater (e.g. components of pulp mill effluents, non-halogenated hydrocarbon pesticides, degration products of contaminants). Thus, it appears to be fairly difficult to assess the degree of pollution of the Baltic Sea by organic substances, because any estimation of the relative hazard to the ecosystem of the small number of frequently measured organic substances must be regarded as little more than an educated guess. The question arises: Why has the attention of organic marine chemists been focused on mineral oil (hydrocarbons) and chlorinated hydrocarbons? For several reasons: the amount of material introduced into or transported across the Baltic, known toxicities, the obvious ecological impact of large scale oil contamination which, although the Baltic Sea has been spared a catastrophe so far, is an ever present threat, and the relative ease with which these substances are analysed. It is no secret that a flame ionization detector equipped gas chromatograph is an instrument as ideally suited for hydrocarbon trace analysis as a GC furnished with an electron capture detector for the detection and measurement of chlorinated hydrocarbons. However, the almost exclusive emphasis on hydrocarbons and chlorinated hydrocarbons in no way reflects an indolence on the part of the analyst, it merely accentuates the fact that marine organic trace analysis remains a formidable challenge in spite of all improvements made in the recent past. It is important to recognize that here a gap exists of unknown magnitude and significance concerning possible organic contaminants of the Baltic Sea and their ecological impact. This gap, which is not unique to the situation in the Baltic but to some degree exists in every ocean environment, may 210 be closed by a careful search for organic trace constituents of seawater. In this search, difficulties are encountered less with methods of analysis which have been developed to a fairly high degree of sophistication, e.g. computerized gas chromatography-mass spectrometry, than with the very low concentrations of organic substances in seawater, whether indigenous or man-made. Successful attempts have been made to overcome this problem (Ahnoff & Josefsson, 1974; Osterroht, 1974; Ehrhardt, 1978) which should lead to a broader understanding of marine organic chemistry in general and the degree of pollution of the Baltic in particular. After these introductory remarks I shall now try and assess the situation in the Baltic with respect to pollution by mineral oil (fossil hydrocarbons), chlorinated hydrocarbon type pesticides, and polychlorinated biphenyls (PCBs).

Hydrocarbon geochemistry of the Puget Sound region—II. Sedimentary diterpenoid, steroid and triterpenoid hydrocarbons

Cyclic components of the ‘aliphatic’ hydrocarbon mixtures extracted from Puget Sound sediment cores include a suite of C 19 and C 20 diterpenoid hydrocarbons of which fichtelite. sandaracopimaradiene, and isopimaradiene have been identified. Although apparently also derived from vascular plants, these diterpenoid hydrocarbons have relative abundances distinctly different from the co-existing plant wax n-alkane suite. Five C 27, C 28 and C 29 diasteranes and four C 29, C 30 and C 31 17α(H), 21β(H) hopanes occur in relatively constant proportion as components of a highly weathered fossil hydrocarbon assemblage. These chromatographically resolved cycloalkanes. along with the strongly covarying unresolved complex mixture, have been introduced to Puget Sound sediments from adjacent urban centres at increasing levels over the last 100 yr in the absence of any major oil spill. Naturally-occurring triterpenoid hydrocarbons, including hop-22(29)-ene (diploptene), are also present. A new group of C 30 polyenes has been detected which contains compounds apparently structurally related to a co-existing bicyclic C 25 diene and to C 20 and C 25 acyclic multibranched hydrocarbons described in a previous paper ( Barrick et al., 1980).

Pollutant Distribution: A Review of Hydrocarbons in Marine Sediments

Over the last century, human activity has resulted in an increasing rate of release of hydrocarbons that, in one way or another, have become parts of marine sediments. This trend is especially evident in sediments that have been deposited in the vicinity of industrialized urban centres.In this paper, hydrocarbon distribution-patterns of coastal marine sediments near to two urban centres (Providence, Rhode Island, and Los Angeles, California) are examined in detail. At each location the spatial distribution of sedimentary hydrocarbons shows the greatest concentrations in areas of natural sediment-deposition near to the urban center. Examination of sediment cores from these areas shows that fossil hydrocarbons have increased from a minor fraction of total sedimentary hydrocarbons a century ago to being the major contributors today. Results from other industrialized areas of North America and Europe indicate that these patterns are typical.Sediments that are remote from population centres have markedly lower concentrations of hydrocarbons than those deposited near to such centres, as might indeed be expected. Yet indications of anthropogenic contributions of hydrocarbons are detectable even in remote polar locations. In addition to hydrocarbons coming directly from fossil fuels, aromatic hydrocarbons that had been formed during incomplete combustion of other carbonaceous material, also accumulate in marine sediments. Fortunately, hydrocarbons from these two sources (fossil-fuel and other combustion) can be distinguished chemically.

Carbon: The real limit to growth

Under preindustrial conditions the quantities of animal and vegetable life on Earth were fixed by the rate at which animals and microorganisms could restore carbon to vegetation through atmospheric carbon dioxide. The combustion of fossil hydrocarbons has disturbed this balance by bringing “new” organically useable carbon into the ecosystem. The biomass and free carbon dioxide on the Earth has accordingly increased since the industrial revolution and will continue to increase until and beyond the cessation of hydrocarbon-based technology. The author presents arguments in support of this hypothesis and indicates in the Appendix how the carbon cycle and its response to disturbances might be treated mathematically.

Application of glass capillary columns to monitor petroleum-type hydrocarbons in marine sediments.

High resolution glass capillary columns coated with SE 52 liquid phase were used to resolve the indigenous hydrocarbons extracted from sediment samples collected from three outer continental shelf areas. The extracts were than spiked with small amounts of aliphatic or aromatic components isolated from a Louisiana crude oil and rechromatographed. The resolution was sufficient to separate almost all the isoprenoid, branched and cyclic alkanes associated with petroleum. Additionally, many of the key petroleum aromatics could also be resolved from naturally occurring organics. Such chromatographic procedures will aid in distinguishing between indigenous hydrocarbons of contemporary origin and those known to be associated with fossil hydrocarbon pollution of marine sediments.

Thyristor trigger circuit using a 555 IC timer : V. N. Neelakantan and A. Krishnan. Int. J. Electron.42, (5) 515 (1977)

The demand for green hydrogen is growing as the increasing production of pure hydrogen can no longer be based on fossil hydrocarbons. As water electrolysis would move from niche to a significant consumer of emission-free electricity, the efficiency of electrolytic gas production, lifetime of water electrolysis systems, and balance in the electricity grid become essential. The operational and investment costs of an industrial-scale alkaline water electrolyzer with four practical rectifier topologies are investigated. The results show thyristor-based rectifiers provide poor quality for the AC and DC sides, which leads to nonoptimal specific energy consumption (SEC) of the water electrolyzer and a notable reactive power component. Transistor-based topologies may offer up to 4.5% lower SEC of the electrolyzer than the conventional 6-pulse thyristor bridge. The reactive power results in additional costs in either investments in compensation equipment or regular allowance costs. An additional DC/DC converter can be installed to improve the power quality for the electrolyzer, but the second conversion stage adds to the system complexity and cost without eliminating reactive power. A modular single-stage rectifier based on insulated-gate bipolar transistor (IGBT) bridges is suggested as an alternative to provide improved power quality for both the electrolyzer and the electricity grid.

Stimulation of oleoresin yield in conifers

Techniques for chemical stimulation of pine oleoresins have industrial and sociological advantages beyond the immediate profit to be derived from greater volume of production per man day or per tonne of pulpwood. They could increase opportunities of employment in remote forested areas, and constitute a step towards conserving world energy supplies by using renewable sources of plant-fabricated molecules instead of energy-intensive synthetic products from fossil hydrocarbons.

Discrimination in the assimilation of n-alkanes in fish.

VERY large quantities of hydrocarbons have been and continue to be introduced into the seas and oceans by the various activities of man1,2 but estimates of this input and comparisons with biogenically-derived material or seepage from fossil hydrocarbon deposits are difficult to make. An assessment of the general effects of non-biogenic hydrocarbons on the marine ecosystem is equally difficult.

Ubiquity of hydrocarbons in nature: Aliphatic hydrocarbons in weathered limestone

The aliphatic hydrocarbons in two specimens of limestone (one from Texas and the other from Italy) which were weathered in place as parts of building structures have been investigated using gas chromatography and gas chromatography-mass spectrometry. The hydrocarbons in 1. (i) the limestone from Texas and 2. (ii) algae cultured from this limestone have similar distributions, i.e. the predominating hydrocarbon in both cases is n-C 17, thus indicating that most of the aliphatic hydrocarbons in the limestone may be derived from recent algal growth. The hydrocarbons in the limestone from Italy, in which n-C 17 is a maximum but which also include relatively large amounts of pristane, phytane and other aliphatic hydrocarbons, appear to be a mixture of in situ biogenically derived hydrocarbons and extraneously derived fossil hydrocarbons.

Bute Inlet Wax

BUTE Inlet is one of the larger fiords on the mainland coast of British Columbia: it discharges into a complex system of channels at the north end of the Gulf of Georgia at a latitude of about 50° 30′ N. During unusually cold winters a yellowish wax-like substance has been observed floating on the waters of the inlet1. The natural occurrence of lipid material in massive form is of possible interest in relation to the elaboration of petroleum and other fossil hydrocarbon deposits and we have therefore examined the constitution of Bute Inlet wax in some detail in an attempt to throw more light on its origin.