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Showing papers on "Coal published in 1990"


Book
01 Jul 1990
TL;DR: In this article, the origins of trace elements in coal and the mode of occurrence of trace element in coal were investigated. But the results were limited to trace element detection in coal.
Abstract: Origin of trace elements in coal mode of occurrence of trace elements in coal methods of analysis contents of trace elements in coals comparisons of coal with shale and soil variations within seams radioactivity and coal relevance of trace elements in coal.

817 citations


Journal ArticleDOI
01 May 1990-Fuel
TL;DR: In this article, the authors investigated the relationship between the coal matrix shrinkage and the gas flow path in coalbeds and found that the coal volume shrinks by ≈ 0.4% when the gas pressure falls from 6.9 MPa to atmospheric pressure.

366 citations


Journal ArticleDOI
TL;DR: In this paper, the genesis of macerals in brown coals is discussed in the light of recent advances that have been made in the study of coals and modern peats.

361 citations


Journal ArticleDOI
TL;DR: In this article, a chemical percolation devolatilization (CPD) model is used to describe the effects of heating rate and temperature on tar and gas release from coal.
Abstract: The chemical percolation devolatilization (CPD) model previously developed to describe the devolatilization behavior of rapidly heated coal was based on the chemical structure of the parent coal. Percolation lattice statistics are employed to describe generation of finite tar clusters as labile bonds are cleaved in the infinite coal lattice. The model is used here to describe effects of heating rate and temperature on tar and gas release from coal. Results indicate that the CPD models predictions yied good agreement with published data for a wide range of coals and particle heating rates

249 citations


Journal ArticleDOI

248 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the variations in cross-linking with several parameters (rank, temperature, heating rate, pretreatment, etc.) to identify the factors that control cross-link rates.
Abstract: During coal conversion, the breakup of the coal macromolecular network and resulting product formation are controlled by the relative rates of bond breaking, cross-linking, and mass transport. THe objective of this work was to systematically study the variations in cross-linking with several parameters (rank, temperature, heating rate, pretreatment, etc.), to identify the factors that control cross-linking rates. This paper describes a study of cross-linking behavior in which chars of a number of coals (including the Argonne premium coal samples) have been pyrolyzed under a variety of temperature histories and analyzed at intermediate extents of pyrolysis for solvent swelling behavior and functionnal group compositions

232 citations


Journal ArticleDOI
TL;DR: In this paper, the authors used a steam-cooled tube at the exit of a pilot scale furnace during combustion of bituminous coal to identify coal properties and combustion conditions with which one may anticipate fouling and slagging of superheaters in electric utility boilers.

208 citations


Journal ArticleDOI
01 Feb 1990-Fuel
TL;DR: In this article, a char morphology system based on the physical and optical characteristics known to influence the burning of pulverized coal is outlined, and the proportions of different pyrolysis char types produced by any coal are shown to depend on coal rank, petrographic composition, maceral fusibility, and possibly ash content and composition.

207 citations


Journal ArticleDOI
TL;DR: In this article, a review of thermal decomposition of selected hydrocarbons that serve as models for processing of coal is presented, focusing on elementary radical processes for bond breaking, bond making, and hydrogen transfer.
Abstract: Mechanisms are reviewed for thermal decomposition of selected hydrocarbons that serve as models for processing of coal. The hydrocarbon classes emphasized are aromatics, alkylaromatics, α,ω-di-arylalkanes, and hydroaromatics, especially tetralin. Perturbations by added sources of hydrogen, especially H 2 and hydroaromatics, are also covered. Free-radical pathways dominate. Emphasis is placed on quantitative understanding of elementary radical processes for bond breaking, bond making, and hydrogen transfer and on the response of the competitions among these to hydrocarbon structure and reaction conditions. Selected implications for coal processing are drawn

181 citations


Journal ArticleDOI
TL;DR: In this article, the effects of combustion and leaching on 30 elements were analyzed using eight Argonne Premium Coal samples and two other coal samples, and the results were used to infer the modes of occurrence of these elements.
Abstract: Eight Argonne Premium Coal samples and two other coal samples were used to observe the effects of combustion and leaching on 30 elements. The results were used to infer the modes of occurrence of these elements. Instrumental neutron activation analysis indicates that the effects of combustion and leaching on many elements varied markedly among the samples. As much as 90% of the selenium and bromine is volatilized from the bituminous coal samples, but substantially less is volatilized from the low-rank coals. We interpret the combustion and leaching behavior of these elements to indicate that they are associated with the organic fraction. Sodium, although nonvolatile, is ion-exchangeable in most samples, particularly in the low-rank coal samples where it is likely to be associated with the organic constituents. Potassium is primarily in an ion-exchangeable form in the Wyodak coal but is in HF-soluble phases (probably silicates) in most other samples. Cesium is in an unidentified HNO 3 -soluble phase in most samples. Virtually all the strontium and barium in the low-rank coal samples is removed by NH 4 OAc followed by HCl, indicating that these elements probably occur in both organic and inorganic phases. Most tungsten and tantalum are in insoluble phases, perhaps as oxides or in organic association. Hafnium is generally insoluble, but as much as 65% is HF soluble, perhaps due to the presence of very fine grained or metamict zircon. We interpret the leaching behavior of uranium to indicate its occurrence in chelates and its association with silicates and with zircon. Most of the rare-earth elements (REE) and thorium appear to be associated with phosphates. Differences in textural relationships may account for some of the differences in leaching behavior of the REE among samples. Zinc occurs predominantly in sphalerite. Either the remaining elements occur in several different modes of occurrence (scandium, iron), or the leaching data are equivocal (arsenic, antimon

177 citations


Patent
20 Apr 1990
TL;DR: In this paper, a method of increasing the rate of methane production from a coal seam includes introducing a desired volume of a gas, that causes coal to swell, into the coal seam adjacent a well-bore, maintaining the coal seams adjacent the wellbore in a pressurized condition for a period of time to permit the gas to contact a desired area of the coal adjacent to the well bore, and relieving the pressure within the coal seep by permitting fluids to flow out from the well bore at a rate essentially equivalent to the maximum rate permitted by the surface wellb
Abstract: A method of increasing the rate of methane production from a coal seam includes introducing a desired volume of a gas, that causes coal to swell, into the coal seam adjacent a wellbore, maintaining the coal seam adjacent the wellbore in a pressurized condition for a period of time to permit the gas to contact a desired area of the coal adjacent the wellbore, and relieving the pressure within the coal seam by permitting fluids to flow out from the wellbore at a rate essentially equivalent to the maximum rate permitted by the wellbore and any surface wellbore flow control equipment. Uneven stress fractures should be created in the coal by this method which will increase the near wellbore permeability of the coal seam.

Journal ArticleDOI
TL;DR: In this article, the authors synthesize together the available information on both of these fronts to facilitate understanding of those coal conversion technologies where either or both of the phenomena may play an important role.

Journal ArticleDOI
TL;DR: In this paper, a series of coalified gymnospermous wood ranging in rank from brown coal to subbituminous coal by solid-state 13 C NMR and analytical pyrolysis has provided sufficient information to construct structural models depicting the changes that occur to lignin.


Journal ArticleDOI
TL;DR: In this article, the TG-FTIR was used for pyrolysis, oxidation, and combustion of Argonne premium coal samples, and a kinetic analysis was applied to species evolution data collected at several different heating rates.
Abstract: This paper describes the most recent improvements in the apparatus and presents its application in characterizing the Argonne premium coal samples. The TG-FTIR apparatus for pyrolysis, oxidation of pyrolysis products, and oxidation of the sample is described. To analyze coal, a sequence of drying, pyrolysis, and combustion is employed to obtain proximate analysis, volatile composition, volatile kinetics, and relative char reactivity. Pyrolysis results are presented for the eight Argonne coals, several demineralized coals, and two oxidized samples of Pittsburgh Seam coal. A kinetic analysis was applied to species evolution data collected at several different heating rates. There is a systematic variation in rate with rank

Journal ArticleDOI
01 Feb 1990-Fuel
TL;DR: An alternative use for coal ash was investigated, based on the metakaolin type material present in the ash as discussed by the authors, which was treated with sodium hydroxide at different concentrations and various times and temperatures of crystallization.

Book
26 Jan 1990
TL;DR: In this paper, the focus is on new methods and known technologies that assist in the development of unconventional worldwide fossil fuel resources comparing petroleum to other fossil fuels, such as tar sands and heavy oils, bitumen, coal, oil shale, and natural gas.
Abstract: The focus here is on new methods and known technologies that assist in the development of unconventional worldwide fossil fuel resources comparing petroleum to other fossil fuels, such as tar sands and heavy oils, bitumen, coal, oil shale, and natural gas. The contributions contrast scientific and t

Journal ArticleDOI
TL;DR: In this paper, eleven selected coals were burned under controlled conditions in a laboratory combustion furnace to determine the effect of coal type on the amount and composition of combustion generated inorganic submicron particles.
Abstract: Eleven selected coals were burned under controlled conditions in a laboratory combustion furnace to determine the effect of coal type on the amount and composition of combustion generated inorganic submicron particles. Significant differences in both the amount and composition of submicron particles were found between coals and particularly between rank of coals. In most cases, however, the extent to which an element appeared in the submicron fume could be correlated on the basis of its occurrence and distribution in the coals.

Patent
25 May 1990
TL;DR: In this article, a co-generation configuration employing the hydrodisproportionation of coal is proposed to minimize char and gas production without utilization of external hydrogen, that is, hydrogen other than that contained in the coal feedstock.
Abstract: A method for preparing coal-derived fuel compositions while simultaneously producing electricity by utilizing a novel co-generation configuration employing the hydrodisproportionation of coal. Hydrodisproportionation is the short residence time decomposition and volatilization of coal to produce liquid coproducts, minimizing char and gas production without utilization of external hydrogen, that is, hydrogen other than that contained in the coal feedstock. The char produced is gasified to simultaneously produce steam for electrical power generation and syngas to produce methanol in a once-through process. The methanol purge gas is used as a fuel gas for a gas-driven power generating turbine. The waste heat from the power generation is used as the process heat for hydrodisproportionation.

Journal ArticleDOI
01 Dec 1990
TL;DR: In this article, the authors describe the behavior of coalbeds as gas reservoirs and discuss the results of a study carried out to establish the effect of release of methane on gas flow behaviour of coal, which consisted of microscopy, establishing adsorption/desorption isotherms, and monitoring changes in the volume of coal matrix with increasing and decreasing gas pressure.
Abstract: This paper describes the behaviour of coalbeds as gas reservoirs and discusses the results of a study carried out to establish the effect of release of methane on gas flow behaviour of coal. Experimental work consisted of microscopy, establishing adsorption/desorption isotherms, and monitoring changes in the volume of coal matrix with increasing and decreasing gas pressure. Micrographs obtained using small pieces of coal indicated that coal is made up of blocks, containing matrix and pores, separated by microfractures. This confirms the dual porosity model of coal structure with a primary porosity, and a fracture/cleat porosity-physical model used in coalbed methane simulators developed recently. Isotherms suggested that for the samples tested, a major part of the gas is released only after pressure falls below 600 psi, and this is primarily due to desorbing gas. Results of the volumetric strain experiments indicated that there is an increase in matrix volume with increase in gas pressure, in spite of matrix compressibility. Adsorption, therefore, induces swelling of the matrix. With decrease in gas pressure from 1000 psi to atmospheric, the matrix volume shrunk by 0.5%. These experimental results were inputted in a reservoir model and simulation runs made to determine the effect of pore volume and matrix shrinkage compressibilities on gas production. Over a five year period 60% more gas was produced when matrix shrinkage was used as an input parameter.

Journal ArticleDOI
01 Aug 1990-Fuel
TL;DR: In this paper, a sulphur K edge X-ray absorption spectroscopic method has been developed for direct determination and quantification of the sulphidic and thiophenic forms of organically bound sulphur in nonvolatile petroleum and coal samples.

Journal ArticleDOI
TL;DR: These findings were in agreement with the epidemiological data, which showed that the Xuan Wei residents using smoky coal as a major fuel in homes had a high lung cancer mortality rate.
Abstract: The rural Xuan Wei County, Yunnan Province, China, has an unusually high lung cancer mortality rate that cannot be attributed to tobacco smoke or occupational exposure. The lung cancer rate is associated with 'smoky' coal, in contrast to wood or 'smokeless' coal burned in unventilated homes. This study was conducted to characterize and compare mouse skin tumorigenicity of the coal and the wood combustion emissions and to link the animal data to human lung cancer. Indoor air particles (less than 10 microns) were collected from a central commune where the lung cancer mortality rate is high and smoky coal is the major fuel used and also from a south-western commune where lung cancer mortality rate is low and where wood or smokeless coal are the major fuels used. The organic extracts of these indoor air particles from smoky coal, smokeless coal and wood combustion were analysed for polycyclic aromatic hydrocarbons and assayed for skin tumor initiation activity and complete carcinogenicity in SENCAR mice. The results showed that the organic extract of the emission particles from smoky coal combustion is the most active in tumor initiation among the three combustion emission samples followed by smokeless coal and then wood. The organic extract of the particles from smoky coal combustion was shown to be a potent complete carcinogen, whereas the wood extract was relatively inactive as a complete carcinogen. The extract of particles from the smokeless coal combustion was not tested for complete carcinogenicity because of inadequate supply. Eighty-eight percent of the mice treated with the smoky coal extract showed carcinomas, averaging 1.1 carcinomas per tumor-bearing mouse at the end of the 77 week study. These findings were in agreement with the epidemiological data, which showed that the Xuan Wei residents using smoky coal as a major fuel in homes had a high lung cancer mortality rate. This study demonstrates that the results of the tumorigenicity assays in mice were in agreement with human lung cancer data.

Journal ArticleDOI
TL;DR: The transformation of minerals and dispersed inorganic constitutents during pulverized coal combustion has been examined by burning utility sized coals (70% less than 200 mesh) in a laboratory-scale combustor.

Book ChapterDOI
29 Jun 1990

Journal ArticleDOI
TL;DR: The coal seams in North China and South China were essentially controlled by paleogeography, paleoclimate and plate tectonics, and the characteristics of their coal deposits differ substantially as mentioned in this paper.

Journal ArticleDOI
01 Jan 1990-Fuel
TL;DR: In this article, the biomarker assemblage in the aliphatic fraction of the Tertiary brown coal from Zhoujing mine has been documented in detail, which consists of resin-derived diterpenoid and sesquiter-penoid hydrocarbons, long chain n-alkanes from vascular plant epicuticular waxes, and to a lesser extent terrigenous triterpenes.

Journal ArticleDOI
01 Mar 1990-Fuel
TL;DR: In this article, pyrolysis tar and char yields were measured at atmospheric pressure between 400-800 °C in three reactors with significantly different design characteristics: a fluidized bed; a wire-mesh reactor; and a hot-rod fixed bed reactor.

Journal ArticleDOI
Makoto Shimoda1, Akira Sugano1, Kimura Toru1, Y. Watanabe, K. Ishiyama 
TL;DR: In this paper, a method for predicting unburnt carbon in a coal-fired utility boiler has been developed using an image processing technique, which consists of an imageprocessing unit and a furnace model unit.
Abstract: A method for predicting unburnt carbon in a coal-fired utility boiler has been developed using an image processing technique. The method consists of an image processing unit and a furnace model unit. The temperature distribution of combustion flames can be obtained through the former unit. The latter calculates dynamics of the carbon reduction from the burner stages to the furnace outlet using coal feed rate, air flow rate, and the chemical and ash content of the coal. An experimental study in the Sendai Power Station of Tohoku Electric Company Inc. shows that the prediction error of the unburnt carbon can be reduced to 10%. The results show that the unburnt carbon prediction algorithm could be widely used for evaluation, optimization and diagnosis of combustion systems for various boiler and coal types. >

Journal ArticleDOI
TL;DR: In this article, the authors summarized research to optimize the performance of some of these cultures, and discussed experimental results and models for several reactor designs, including CSTR and packed columns.
Abstract: Liquid and gaseous fuels may be produced biologically from coal by the indirect conversion of coal synthesis gas. Methane has been produced from synthesis gas using acetate and CO2/H2 as intermediates, utilizing a number of CO-utilizing and methanogenic bacteria. Also, a bacterium that is capable of producing ethanol from synthesis gas through indirect liquefaction has been isolated fron natural inocula. This paper summarizes research to optimize the performance of some of these cultures. These conversions, involving H2 and CO, which are only slightly soluble in the liquid media, may be mass transfer limited, and methods to enhance mass transport are examined. Experimental results and models for several reactor designs, including CSTR and packed columns, are presented and discussed.

Journal ArticleDOI
TL;DR: In this article, the Hernshaw-Fire Clay coal bed has been identified as a domed peat swamp, and the inferred paleoecology and vertical stratification of each of these four floral groupings is similar in structure to the “phasic” floral communities found in modern peat systems.