Showing papers on "Coal published in 1997"
Patent•
22 Sep 1997
TL;DR: In this article, a system for recovery of hydrocarbons or thermal energy from host-rock fotions bearing coal, oil-shale, tar-sands or oil by use of a hydrologic cell is described.
Abstract: A system for recovery of hydrocarbons or thermal energy from host-rock fotions bearing coal, oil-shale, tar-sands or oil by use of a hydrologic cell which conveys a reacting fluid under pressure to a source-aquifer, thereafter extracting thermal energy or hydrocarbons from said host-rock, moving said hydrocarbons or thermal energy to said sink-aquifer and then removing the hydrocarbons or thermal energy to the surface for ultimate use.
352 citations
TL;DR: In this paper, the coalbed methane capacity of Bowen Basin coal from the Bowen Basin of Queensland, Australia was investigated and related to other coal properties, including surface area and coal surface area.
309 citations
TL;DR: In this article, the authors developed a model with multiple resources and grades and multiple demands for the world economy and showed that if historical rates of cost reduction in the production of solar energy are maintained, more than 90 percent of the world's coal will never be used.
Abstract: The theory of resource extraction has focused primarily on extraction when there is a single, homogeneous demand for the resource. In reality, however, we observe the simultaneous extraction of different resources such as oil, coal, and natural gas and multiple demands such as trasportation, residential and commercial heating, and electricity generation. This paper develops a model with multiple resources and grades and multiple demands. The model is simulated with extraction cost, estimated reserves, and energy demand data for the world economy. It is shown that if historical rates of cost reduction in the production of solar energy are maintained, more than 90 percent of the world's coal will never be used. The world will move from oil and natural gas use to solar energy. Global temperatures will rise by only about 1.5–2 degrees centigrade by the middle of the next century and then decline steadily to preindustrial levels, even without carbon taxes. These results are significantly lower than those predi...
265 citations
TL;DR: In this paper, the mass balance argument, based on a 2 to 1 coal-sorption selectivity for CO2 over CH4, supports the feasibility of building and operating fossil-fuelled green power plants.
230 citations
TL;DR: The Cayirhan mine, Beypazari basin, Turkey contains an average of 28.5% mineral matter, consisting up to 80% zeolites as discussed by the authors, and the coal seam is split by a 1m-thick tuffaceous siltstone into the upper, first (Tv) and lower, second (Tb) seams, which contain essentially different zeolite.
213 citations
TL;DR: In this paper, the results available in the literature relating nitrogen oxide emissions to coal and char properties are discussed in terms of the mechanisms for production of nitrogen oxides and their reduction in the pores or on the surface of the char.
211 citations
TL;DR: In this paper, the formation, agglomeration and properties of coal-derived soot, including pyrolysis experiments and combustion experiments, are reviewed, as well as the types of experiments performed, the soot yields obtained, the size of the coal particles, the optical properties, the relationship between coal derived soot and soot from simple hydrocarbons, and attempts to model soot in coal flames.
185 citations
TL;DR: In this article, the trace elements in coal and coal ash have concentrations greater than their respective worldwide average contents (Clarke values) and the highest values in coal ash are displayed by elements such as Rb, Cs, Ba, Cu, Sb, Bi, U and Ag.
180 citations
TL;DR: The available data suggest that the hazard of coal fly ash is not to be assessed by merely adding the hazards of individual components, and a closer investigation of 'matrix' effects on silica's toxicity in general seems an obligatory step in future risk assessment on fly ashes and other particles that incorporate silica as a component.
Abstract: Coal fly ashes (CFA) are complex particles of a variable composition, which is mainly dependent on the combustion process, the source of coal and the precipitation technique. Toxic constituents in these particles are considered to be metals, polycyclic aromatic hydrocarbons and silica. The purpose of this review was to study the in vitro and in vivo data on coal fly ash and relate the studied endpoints to the role of (crystalline) silica, considering its recent classification as a human carcinogen. For most of the effects coal mine dust was chosen as a reference, since it contains up to 10% of crystalline silica (alpha-quartz) and is well studied both in vivo and in vitro. Most studies on fly ash toxicity were not designed to elucidate the effect of its silica-content nor did they include coal mine dust as a reference. Taking this into account, both in vitro and in vivo experimental studies show lower toxicity, inflammatory potential and fibrogenicity of CFA compared to silica and coal mine dust. Although in vitro and in vivo studies suggest genotoxic effects of fly ash, the data are limited and do not clarify the role of silica. Epidemiological studies in fly ash exposed working populations have found no evidence for effects commonly seen in coal workers (pneumoconiosis, emphysema) with the exception of airway obstruction at high exposure. In conclusion, the available data suggest that the hazard of coal fly ash is not to be assessed by merely adding the hazards of individual components. A closer investigation of 'matrix' effects on silica's toxicity in general seems an obligatory step in future risk assessment on fly ashes and other particles that incorporate silica as a component.
163 citations
TL;DR: In this paper, the authors present a survey on CO2 removal from fossil-fuelled power generation systems, including 60 variants of power plants with carbon dioxide removal, and compare the efficiency of these variants for a standardized CO2 pressure, and conclude that the IGCC combined with CO shift conversion and physical absorption is the most appropriate option.
161 citations
TL;DR: In this article, the pore volume filling/potential theory was used to fit the Langmuir equation to both high-pressure (up to 10 MPa) and high-temperature (> 1.5 T c ) methane isotherm data.
TL;DR: In this paper, an ash deposition submodel, which includes the effects of both ash chemistry and operating conditions on slagging deposits, has been incorporated into the comprehensive combustion code, PCGC-3.
Journal Article•
TL;DR: In this article, coal seam gases from the Permian Sydney and Bowen basins, Australia, were characterized by methane/ethane ratios greater than or equal to 1000, and showed that microbial reduction of CO2 rather than traditional thermogenic reactions is mainly responsible for gas composition.
TL;DR: In this paper, the pyridine swelling of Pittsburgh No. 8 coal was investigated by differential scanning calorimetry and showed that the coal structure changes with the rearranged coal being more associated.
Abstract: Native coals are strained and glassy. When coals are swollen, this strain is relieved as the coal structure rearranges to a lower free energy and more highly noncovalently associated state. Four coals ranging in carbon content from 77% C to 84% C were warmed in the weak swelling solvent chlorobenzene at 132 °C for 2 weeks and samples were withdrawn at intervals. After evaporation of the chlorobenzene, the pyridine extractability of the treated coals had decreased, sometimes by a factor of 2. The pyridine swelling of Pittsburgh No. 8 coal was sharply reduced. The extractability and swelling decreases with time demonstrate that changes in coal structure occurred with the rearranged coal being more associated. This increased association is not due to hydrogen bond formation because pyridine is known to break most if not all of the hydrogen bonds which occur in coals. The rearranged Pittsburgh No. 8 coal was studied by differential scanning calorimetry. Over the 2 week chlorobenzene reflux period, the heat ca...
TL;DR: A country-by-country survey of coal ash in concrete is presented in this paper, where coal ash production and utilization in the world is summarized and a country-level survey is presented.
Patent•
09 Dec 1997
TL;DR: Carbon dioxide from a boiler flue gas stream is separated, recycled and utilized for gasification of coal or biomass to increase fuel utilization and to decrease the carbon dioxide emissions into the atmosphere as discussed by the authors.
Abstract: Carbon dioxide; from a boiler flue gas stream is separated, recycled and utilized for gasification of coal or biomass to increase fuel utilization and to decrease the carbon dioxide emissions into the atmosphere
TL;DR: In this article, the influence of the severity of heat treatment of coals during pyrolysis and/or early stages of carbon oxidation on the reactivity of the resulting char towards further gasification was investigated.
01 Feb 1997
TL;DR: In this paper, the authors pointed out that power generation in Europe and elsewhere relies heavily on coal as the source of energy and this reliance will increase in the future as other fossil fuels become progressively more expensi...
Abstract: Power generation in Europe and elsewhere relies heavily on coal as the source of energy and this reliance will increase in the future as other fossil fuels become progressively more expensi...
TL;DR: In this paper, the authors investigated the coal permeability of high and medium-volatile bituminous Cretaceous coal at the megascopic and microscopic scale utilizing a pressuredecay permeameter.
TL;DR: A recently completed, multi year study concluded that the assertion that global warming could be reduced by replacing coal and oil fuels with natural gas could not be defended.
TL;DR: In this paper, the results of geological, petrographical, geochemical and mineralogical studies performed to determine the geological controls on coal quality of the Fuxin deposit, Liaoning Province, in northeast China are summarized.
TL;DR: In this paper, coal oxidation was conducted at 200 °C in O2 for 6 hours and the carbonization of the oxidized coal exhibited a broader volatile evolution with respect to temperature and the resulting char from the oxidised coal had a larger surface area.
TL;DR: In this article, the firing behavior of fly ash and the ceramic mixtures was investigated by determining their changes in mineralogy and basic ceramic properties such as colour, bulk density, water absorption and firing shrinkage.
Patent•
05 Dec 1997
TL;DR: In this article, a coal agglomerate is produced by the combination of coal fines with a binder obtained by the direct liquefaction of biomass material, which is carried out in the absence of oxygen at typical temperatures between about 450 and 700° F. and typical pressures between 200 and 3,000 psi.
Abstract: A coal agglomerate is produced by the combination of coal fines with a binder obtained by the direct liquefaction of biomass material. The direct liquefaction is carried out in the absence of oxygen at typical temperatures between about 450 and 700° F. and typical pressures between 200 and 3,000 psi, according to known liquefaction processes. The liquefied bio-binder base is mixed with additives, if desired, such as fast pyrolysis tars and petroleum asphalt, in order to modify its characteristics to meet specific needs of particular applications, and the resulting mixture is sprayed on coal fines preheated to at least 250° F. and allowed to react at about 300-400° F. Combustible extenders and fillers; reinforcing fibers; and cross-linking agents may be mixed with the coal prior to combination with the binder to provide additional specific properties to the mixture. The resulting well mixed mass is then pelletized by the application of pressure in conventional equipment.
TL;DR: In this paper, 13 coals and a char, with volatile matter ranging from 79 to 504 wt% and nitrogen content from 12 to 21 wt%, were evaluated as reburning fuels in an isothermal drop-tube reactor system.
TL;DR: In this paper, the effects of reaction temperature (780 −900°C), oxygen/coal mass ratio (0.30 −0.53), coal feed rate (5.3 −12.1 kg h −1 ) and steam/coal Mass Ratio ( 0.30−0.81) on composition of product gas, carbon conversion, cold gas efficiency and gas yield and calorific value were determined.
01 Jan 1997
TL;DR: In this paper, the concentration, distribution, and form of radioactive elements in coal and fly ash are determined. But, the authors do not consider the effect of radium and thorium in coal.
Abstract: Coal is largely composed of organic matter, but it is trie inorganic matter in coal minerals and trace elements that have been cited as possible causes of health, environmental, and technological problems associated with the use of coal. Some trace elements in coal are naturally radioactive. These radioactive elements include uranium (U), thorium (Th), and their numerous decay products, including radium (Ra) and radon (Rn). Although these elements are less chemically toxic than other coal constituents such as arsenic, selenium, or mercury, questions have been raised concerning possible risk from radiation. In order to accurately address these questions and to predict the mobility of radioactive elements during the coal fuel-cycle, it is important to determine the concentration, distribution, and form of radioactive elements in coal and fly ash.
TL;DR: In this paper, a new method was developed for extracting a great deal of brown coal in several conventionally used solvents at room temperature, and the coal was pretreated with hydrogen peroxide in liquid phase at 6...
Abstract: A new method was developed for extracting a great deal of brown coal in several conventionally used solvents at room temperature. The coal was pretreated with hydrogen peroxide in liquid phase at 6...
TL;DR: In this article, the influence of coal ash on nitrogen oxides was investigated with original, de-ashed and impregnated lignite and hard coal and it was shown that the organic coal structure is not changed by de-ashing.
Patent•
30 Jan 1997
TL;DR: In this paper, a method for increasing the production of methane from a coal formation penetrated by an injection well and a production well by producing methane from the coal formation via the production well, passing a portion of the methane to a synthesis gas generation zone, where at least a portion is reacted with an oxygen-containing gas to produce a mixture of carbon monoxide and hydrogen.
Abstract: A method for increasing the production of methane from a subterranean coal formation penetrated by an injection well and a production well by producing methane from the coal formation via the production well; passing a portion of the methane to a synthesis gas generation zone wherein at least a portion of the methane is reacted with an oxygen-containing gas to produce a mixture of carbon monoxide and hydrogen; passing a major portion of the mixture to a hydrocarbon synthesis zone wherein the carbon monoxide and hydrogen are reacted to produce heavier hydrocarbons and a tail gas comprising nitrogen and carbon dioxide; separating a major portion of the tail gas from the hydrocarbons and recovering the hydrocarbons as a product stream; injecting at least a portion of the tail gas into the coal formation through the injection well. The methane may be obtained from a single well or a plurality of wells operated to produce the methane by a huff and puff process.