Showing papers on "Coal published in 1987"

Reservoir Engineering in Coal Seams: Part 1-The Physical Process of Gas Storage and Movement in Coal Seams

Abstract: This is the first of two papers concerning the movement of gas in coal seams. It deals directly with the physical behavior of the coal seam as a reservoir. Coal seams show considerable differences in behavior from normal porous gas reservoirs in both the mode of gas storage and permeability characteristics. Most of the storage of gas in coal is by sorption into the coal structure, while the coal permeability is cleat-(fracture-) or joint-controlled and may vary over a wide range during production. This permeability fluctuation is not solely a phase relative permeability effect, but is rather a result of the opposing effects of effective stress increase with fluid pressure reduction and shrinkage of the coal. Reducing fluid pressure tends to close the cleats, reducing permeability, while shrinkage tends to open them.

N.M.R. techniques and applications in geochemistry and soil chemistry

Abstract: Elementary n.m.r. theory applicable to geochemistry. Elementary n.m.r. practice applicable to geochemistry. Solution n.m.r. Solid state n.m.r. Minerals and their structure. Precursors to organic matter in the geosphere. Whole soil n.m.r. Humic substances. Oil shale. Peat. Coal. Coal derivatives. Coal conversion.

Lung cancer and indoor air pollution in Xuan Wei, China

Abstract: In Xuan Wei County, Yunnan Province, lung cancer mortality is among China's highest and, especially in females, is more closely associated with indoor burning of "smoky" coal, as opposed to wood or "smokeless" coal, than with tobacco smoking. Indoor air samples were collected during the burning of all three fuels. In contrast to wood and smokeless coal emissions, smoky coal emission has high concentrations of submicron particles containing mutagenic organics, especially in aromatic and polar fractions. These studies suggested an etiologic link between domestic smoky coal burning and lung cancer in Xuan Wei.

Method and apparatus for conversion of coal in situ

Abstract: A method for the electro-thermal and electrochemical underground conversion of coal into oil and by-products comprises the steps of inserting an underground probe into a bore hole until the probe is in close proximity to a coal seam. A mixture of air, steam, an electrolyte and a suitable catalyst is supplied to the probe, and the mixture is then sprayed directly on the coal seam through a passage in a nozzle. The probe is also energized with electricity applied to the nozzle to produce an arc between the coal and the probe, simultaneous with the spraying of the mixture on the coal seam. Heat of the combustion from the arc and the steam combine to produce a pyrolysis, oxidation, and reduction of the coal, thereby converting the coal into a gaseous combination of oil and by-products. The arc can be rotated to increase the tunnel diameter. An apparatus for performing the method is also provided.

Method for producing natural gas from a coal seam

Abstract: Disclosed herein is a method of degasification, wherein gas and water production from a coal field are maintained at high rates regardless of temporary changes in market demand. While all the produced water is disposed, surplus gas is reinjected in coal by converting some of the producers to injectors. When the demand for gas improves, the injection wells are put back on production. Recovery of gas from wells used as injectors is rapid because of increased reservoir pressure and high gas relative permeability near the wellbore.

Investigation of organic sulfur-containing structures in coal by flash pyrolysis experiments

Abstract: Etude des composants contenant du soufre dans des charbons de differents degres de houillification, par pyrolyse eclair isotherme continue et spectrometrie GC/MS

Sulphur in peat and coal

Abstract: Abstract Coal sulphur content is a major consideration in coal marketing. To predict sulphur content and distribution in a coal basin, a sulphur geochemical model needs to be developed. A series of questions are posed regarding coal sulphur distribution, forms and origins. Salient aspects of literature on coal sulphur content and distribution are reviewed to establish a framework for developing a sulphur geochemical model. Some coal sulphur originates from peat-forming processes. Sulphate, ferrous iron, and microorganisms are key ingredients for the origins of coal pyrite and organic sulphur. Hydrogen sulphide is an important intermediate for pyrite and organic sulphur formation in peats. Sulphur isotope values for peat sulphate, plant sulphur, peat pyrite and peat organic sulphur corroborate the hypothesis that microorganisms reduce sulphate to hydrogen sulphide, which in turn reacts with available ferrous iron or organic matter to produce pyrite and organic sulphur respectively.

Electrochemical Oxidation of Molten Carbonate‐Coal Slurries

Abstract: A novel approach for the electrochemical oxidation of coal is described. The electrochemical cell employed an anode of coal or carbon particles dispersed in a molten carbonate electrolyte at 500°–800°C. At these temperatures, the oxidation kinetics of coal/carbon are sufficiently rapid that high current densities can be obtained at an inert working electrode. Results presented for various forms and concentrations of carbon include open‐circuit potentials, current‐voltage curves, and product gas evolution rates. At temperatures of 700°C and above, the measured potentials were in agreement with theoretical values of the redox couple. Product gas analysis indicated that complete oxidation of carbon to was achieved, thus providing the maximum electrochemical conversion efficiency (four electrons per carbon atom). By coupling this anode with an cathode, fuel cell operation (i.e., electricity generation) should be feasible. The primary limitation observed in this study was the heavy chemical consumption of carbon by , which resulted in a low overall carbon conversion efficiency.

Excavation of the Partial Seam CRIP underground coal gasification test site

Abstract: In the fall of 1983, Lawrence Livermore National Laboratory conducted the Partial Seam CRIP (PSC) underground coal gasification (UCG) field experiment at the Washington Irrigation and Development Company mine near Centralia, Washington. The test, in the subbituminous Big Dirty coal seam, lasted 30 days during which time 1400 cubic meters of coal were consumed from two injection/production well combinations. In the spring of 1986, normal mining activity in the vicinity of the PSC test allowed the opportunity to carefully excavate the experiment and examine the post-burn cavities. The mining operation dug out the front and back half of the test area and most of the overburden above the UCG cavities, leaving approximately 23,000 cubic meters of earth containing the main portion of the test area undisturbed. Under direction of the Wyoming Research Institute (WRI), this remaining earth was carefully excavated, in slices perpendicular to the original injection/production line, using small earthmoving equipment to uncover and sample the final burn cavities. Preliminary results of the excavation were presented by WRI at the 12th Underground Coal Conversion Symposium. We present additional results and conclusions based on all of the information obtained. Topics covered include: comparison to material balance and thermal instrumentation data,more » analysis and composition of samples taken from the cavity and general cavity shape and characteristics in comparison with mechanistic models of cavity growth. 10 refs., 10 figs., 1 tab.« less

Fly ash and coal conversion by-products: Characterization, utilization and disposal III

Abstract: This book contains papers relating to the Materials Research Society's symposium on coal combustion products. Included are the following chapters: Thermal properties of coal ashes, Hydraulic properties of fluidized bed combustion ashes, Environmental assessment of bottom ash and fly ash used in road stabilization.

In-situ coal drying

Abstract: A method for upgrading coal in-situ is disclosed in which a treatment zone is established around an energy source placed in a cavity within a coal seam and the pore structure of the coal substantially irreversibly collapses as moisture is driven off. The energy source provides either evaporative energy such as heat or a combination of heat and pressure in-situ. Resorption of water returning to the treatment zone during cooling of the coal prior to mining is limited due to the pore collapse.

Coal, climate and terrestrial productivity: the present and early Cretaceous compared

Abstract: Abstract At the present time, rainfall sufficient and consistent enough for swamp formation and peat preservation occurs in the equatorial and temperate belts. Evaporite deposits and aeolian sandstones occur in the consistently dry areas, while the intermediate areas of seasonal rainfall tend not to have any of these climatically significant sediments. In the Cretaceous, the temperate belts are well represented by coals as today, but the tropical belt is not, and the same can be said of other Mesozoic and early Cenozoic periods. Instead, the tropics are represented by low diversity floras and sediments, like the Nubian Sandstone, which can be interpreted as representative of climates in which precipitation was markedly seasonal. The inference is that the Intertropical Convergence Zone was less latitudinally confined during the warmer ‘greenhouse’ periods, and that this might have been due to weaker polar fronts.

A global atmospheric selenium budget

Abstract: An examination of the major anthropogenic and natural sources of atmospheric selenium indicates that approximately 13–19×109 g Se are cycled through the troposphere annually. Perhaps 60% of this flux is natural in origin, and both man-made and biological emissions appear to be predominantly gaseous in nature. Emissions from the marine biosphere and the combustion of coal account for 50–65% of the total atmospheric selenium emissions, and the natural marine flux appears to be roughly twice as large as that due to coal combustion.

Facies studies of coal and coal-bearing strata

Abstract: Abstract Prior to 1960 most discussions on the depositional environment of coal-bearing strata were related to theories of the origin of cyclothems. Work during the 1960s on modern deltas, particularly the Mississippi, led to the interpretation of the classic cyclothem as deltaic in origin, with coals originating in delta-top swamps. During the 1970s and early 1980s, detailed models of depositional environments were developed for coal-bearing strata. Coals have now been described in association with virtually all types of terrestrial depositional environments. There are surprisingly few published examples of facies analyses of coal-bearing strata. Detailed measured sections and meticulous descriptions of sedimentary structures are necessary for geologists to make independent assessments of published environmental interpretations and to make comparisons between various coal-bearing formations. The coal industry could benefit from more predictive facies models, which will require greater integration of coal and clastic facies studies. In most mires close to areas of active clastic deposition, ash content of peat is too high for them to be precursors of coal. Most coal must have originated as peats in raised mires or in low-lying mires well removed from active clastic environments. In the latter case, a significant hiatus in deposition may be represented by the contact of coal with underlying sediments. Subsurface studies, which allow an understanding of the three-dimensional character of coal-bearing strata, may provide clues as to the type of swamp in which a coal was deposited. Recent studies in the Upper Cretaceous of Alberta, for example, provide clear evidence that coals originated in mires well removed from contemporaneous clastic depositional systems.

Coal slurry fuel technology

Abstract: Volatile oil markets experienced in the seventies have promoted renewed interest in coal-based fuel technologies. Coal-slurry fuels have emerged as viable technical alternatives for oil and gas in utility and industrial boilers. Despite current low prices and the abundance of oil, concerns over its long-term availability and price, as well as strategic considerations, make coal-slurry technology attractive. Initially, coal-slurry fuels were based on coal-oil mixtures, now the emphasis is largely on coal-water fuels. This review assesses the status of the relevant technology. It covers the preparation of coal-slurry fuels, slurry properties, combustion characteristics, emissions, current applications and concludes with their future outlook.

Fuel cells for extraterrestrial and terrestrial applications

Abstract: The fuel cell is a nineteenth century invention and a twentieth century technology development Due to the high power and energy density, high efficiency, reliability, and production of pure water, hydrogen-oxygen fuel cell systems have no competition as auxiliary power sources for space vehicles The alkaline fuel cell system is a well developed and proven technology for this application The solid polymer electrolyte system may be its future competitor The energy crisis of 1973 stimulated research, development and demonstration of the phosphoric acid, molten carbonate, solid oxide and solid polymer electrolyte fuel cell systems using natural gas, petroleum or coal derived hydrogen (and carbon monoxide for the high temperature systems) for terrestrial applications The direct methanol-air fuel cell is still an electrochemist's dream Though considerable technological advances have been made, the present price of crude oil, and the high capital costs and limited lifetime of fuel cell systems impede their terrestrial applications in the developed countries Conversely, the potential for lower capital costs of labor intensive manufacturing processes and the relatively higher fossil fuel prices make these systems more attractive for such applications in the developing countries 11 refs

Solubilization of coal by an extracellular product from Streptomyces setonii 75Vi2

Abstract: Several low-ranked coals were solubilized when placed on the surface of agar cultures ofStreptomyces viridosporous T7A andS. setonii 75Vi2. When grown in submerged cultureS. setonii 75Vi2 produced an extracellular component that was capable of solubilizing coals. The extracellular coal solubilizing component had a molecular weight of <10000 and was heat stable since, after 1h at 121°C, only 30–40% of the activity was lost. Treatment with any of three proteases also appeared to be ineffective in decreasing activity. These results suggest that coal solubilization byS. setonii 75Vi2 is nonenzymatic.

Sources of Atmospheric nitrous oxide from combustion

Abstract: Emissions of nitrous oxide (N2O) have been analyzed from industrial boilers and from a large experimental combustor burning natural gas, oil, or coal. Production of N2O and production of NO(x) were observed to be correlated, with an average molar ratio of 0.58:1 (N2O-N:NO). In conventional single-stage combustors, about 14 percent of fuel nitrogen is converted to N2O and 24 percent is converted to NO(x). Conversion of fuel nitrogen to N2O was much less efficient in a two-stage experimental combustor and in wood fires. A model is presented describing emissions of N2O globally, from the beginning of the industrial revolution to the present. It is expected that concentrations of N2O should rise more than 20 percent to about 367 ppb by the year 2050, based on conservative projections of world energy consumption.

Changes in the chemical structure of low rank coal after low temperature oxidation or demineralisation by acid treatment: Analysis by FTIR and UV fluorescence

Abstract: The studies have been conducted on low rank coal: Flambant de Provence, France, PRV=0.44 FTIR and UV synchronous fluorescence spectroscopy are used to study structural changes in low rank coal after natural oxidation or acid (HCl/HF) demineralization. The observed variations deal mainly with a decrease in aliphatic structures and an increase in the oxygenated species. A quantitative oxidation study of the effect of temperature, time, mineral matter and oxygen concentrations has been conducted by FTIR. An attempt to describe the oxygenated species by FTIR and to compare their evolution has been conducted. Various oxidation mechanisms are proposed according to the results.

Kinetics of vapor-phase secondary reactions of prompt coal pyrolysis tars

Abstract: The kinetics of vapor-phase secondary reactions of newly formed coal pyrolysis tars were studied at temperatures and residence times of 500-900/sup 0/C and 0.6-3.9 s, respectively. Tar vapors, generated by heating a helium-swept, shallow packed bed of Pittsburgh No. 8 bituminous coal from room temperature to 550/sup 0/C, at 3/sup 0/C/min, were either rapidly conveyed to collection traps for subsequent characterization or else passed through an adjacent reactor for controlled thermal treatment prior to trapping. Results are described. A multiple, independent, parallel, first-order reaction model also performed well but could not predict step-like behavior in conversion at 0.6-s residence time. A single-reaction first-order decomposition model correlated the conversion data poorly at 0.6- and 1.1-s residence times, and use of the resulting best fit parameters gave totally inadequate predictions of conversions measured at 2.5 and 3.9 s.

Indoor air sampling and mutagenicity studies of emissions from unvented coal combustion.

Abstract: To develop sampling strategies and bioassay protocols for indoor air containing emissions from coal combustion in homes of the rural Xuan Wei County in China, the authors developed a medium-volume sampler to collect the <10-..mu..m particles and semivolatile organics by a filter and an XAD-2 resin, respectively. A high-volume particulate sampler was used for comparison. The coal was burned under conditions that simulated the open-pit combustion that occurs in Xuan Wei. High-volume and medium-volume sampling yielded similar, high particulate concentrations 38-39 mg/m/sup 3/. Fifteen percent of the total extractable organic mass was collected in the XAD-2 resin, and the remaining 85% was retained in the filter. The polycyclic aromatic hydrocarbons found in the XAD were composed of four or fewer rings. In the Ames Salmonella assay, the XAD sample showed low mutagenic activity, and most of the mutagenic activity was found in the filter. The coal combustion emitted both direct- and indirect-acting mutagens, most of which were frameshift mutagens. 12 references, 2 figures, 3 tables.

Experimentally Determined Overall Burning Rates of Coal Chars

Abstract: Abstract-Simultaneous measurements of the size, temperature, and velocity of single pulverized-coal char particles are used to determine the overall burning rates of the chars flowing in hot. oxidizing gaseous environments. The single film model of a burning carbon particle is employed with CO as the sole heterogeneous reaction product. Arrhenius parameters which describe the chemical reaction rate coefficients are derived for the chars of a hvb-biturninous coal from Missouri, a North Dakota lignite and a high-swelling, bituminous coal from Kentucky. Gaseous environments in the temperature range 14S0 to 1550 K, having one, three and six mole-percent oxygen were employed. The measurements indicate that in the three and six mole-percent oxygen environments, the temperatures of particles in the size range 70 to 150 𝛍m exceed the local gas temperatures by as much as 150 K. The results suggest that at high particle temperatures, the chars of the coals burn in a regime in which the overall particle bur...

Relationships between VA mycorrhizal fungi and plant cover following surface mining in Wyoming.

Abstract: Spoil spore counts of vesicular arbuscular mycorrhiul (VAM) fungi, VAM root infection, and percent cover of plants were assessed on reclaimed soil and spoil (1-6 years old), orphan spoil (lo-31 years old), and undisturbed native sites. There was no relationship of site age with spore densities. Topsoiled sites almost always had significantly higher spore counts than spoil sites (reclaimed or orphan), indicating the importance of substrate on spore colonization and reproduction. Percent root infection of Agropyron smithii and A. dasystachyum showed no increasing trends with time in the mined sites (l-31 years), but the plants in the undisturbed site had greater infection than in any of the mined sites. There was also no correlation between percent cover of Agropyron and root infection or spore counts. These results suggest that time since disturbance is not an adequate explanation for the development of VAM infection and spore counts during the first 31 years, but that other factors such as the kind of substrate may be more important considerations.