Showing papers on "Coal published in 1988"
TL;DR: In this paper, a general model for coal devolatilization is presented, which considers the evolution of gas, tar, char and guest molecules, and combines two previously developed models, a Functional Group (FG) model and a DevolATilization-Vaporization-Crosslinking (DVC) model.
Abstract: This paper presents a general model for coal devolatilization which considers the evolution of gas, tar, char and guest molecules. The general model combines two previously developed models, a Functional Group (FG) model and a Devolatilization-Vaporization-Crosslinking (DVC) model. The FG model considers the parallel independent evolution of the light gas species formed by the decomposition of functional groups. Alternatively, functional groups can be released from the coal molecule attached to molecular fragments which evolve as tar. The kinetic rates for the decomposition of each functional group and for tar formation have been determined by comparison to a wide variety of data, a first approximation, these rates are insensitive to coal rank. The FG model uses an adjustable parameter to fit the total amount of tar evolution. This parameter depends strongly on the details of the time-temperature history of the sample, the external pressure, and the coal concentration and, therefore, varies with the type of experiment performed.
436 citations
TL;DR: Long-term leaching studies predict that fly ash will lose substantial amounts of soluble salts over time, but simulation models predict that the loss of trace elements from fly ash deposits through leaching will be very slow.
233 citations
TL;DR: In this article, the authors present a kinetic model which describes the changes in the composition of oil together with the subsequent formation of gas and coke as a result of the thermal cracking.
172 citations
TL;DR: Several different strains of fungi have been shown to solubilize some types of low‐ranked coal, apparently by an extracellular process, allowing the use of a variety of coal feedstocks and is water‐soluble.
Abstract: This invention deals with the solubilization of coal using species of Streptomyces. Also disclosed is an extracellular component from a species of Streptomyces, said component being able to solubilize coal.
143 citations
TL;DR: In this article, it is speculated that resinite and related macerals might play an especially important role in petroleum expulsion, as evidenced by their high genetic potential and their inherent capability of saturating the source rock pore system.
121 citations
TL;DR: In this article, pyrolysis data from degraded wood and coalified logs or stems was examined for coalification and the results showed several stages of evolution during coalification, including the selective degradation of cellulosic components and preservation of lignin-like components, and the degradation of methoxyl groups with replacement by phenolic hydroxyls such that catechol-like structures are produced.
113 citations
TL;DR: In this article, it was shown that tannins are selectively preserved in bark during coalification to the brown coal stage, which is a useful method for detecting the presence of tannin in geochemical samples including barks, buried woods, peats and leaf litter.
102 citations
TL;DR: In this paper, chemical changes occurring during dry phase oxidation with air of a subbituminous coal have been investigated by FT-i.r. spectroscopy, and the results have shown that the aliphatic structure is more reactive than the aromatic one.
97 citations
TL;DR: In this article, a process for reducing the concentration of pollutants in an effluent from the combustion of a carbonaceous fuel is presented, which consists of injecting a first treatment agent into the effluent at a first temperature zone and injecting a second treatment agent at a second temperature zone, wherein the first and second treatment agents are injected under conditions effective to reduce the pollution index.
92 citations
TL;DR: In this paper, a ligand-exchange chromatography (LEC) method has been used for the isolation of condensed thiophenes (PASH) and other types of aromatic sulfur compounds (S-PAC) based on ligand exchange chromatography.
Abstract: A rapid and simple method has been established for the isolation of condensed thiophenes (PASH) and other types of aromatic sulfur compounds (S-PAC) based on ligand-exchange chromatography (LEC). This procedure has been applied to the aromatic fractions of a crude oil, a coal extract, and a hydrogenated coal liquid to obtain PASH and S-PAC fractions. Both fractions were examined by capillary column gas chromatography with flame ionization and flame photometric detection and by gas chromatography/mass spectrometry. A variety of previously unidentified S-PAC were found in these samples. Alkyl phenyl disulfides were the major S-PAC in the crude oil, and alkylphenylthiophene and propyl naphthyl sulfide were found in the coal extract, while alkyldihydrobenzothiophenes were isolated in the hydrogenated coal liquid. Structural characteristics of the identified S-PAC are discussed and compared with sample properties. The interaction of PASH and S-PAC with PdClz in LEC used in this study was also discussed.
TL;DR: In this article, the authors measured densities, porosities and surface areas of coal macerals and concluded that only a fraction of the surface of coal is composed of hydrophilic sites.
TL;DR: In this article, it was shown that most of the CO2 uptake is not due to imbibing of CO2 within the coal structure but rather to CO 2 uptake in open and closed (to He) micropores.
01 Aug 1988
TL;DR: The results of the recently completed Rocky Mountain I (RMI) underground coal gasification (UCG) field test have shown that the Controlled Retracting Injection Point (CRIP) process for UCG is capable of producing consistently high quality gas from a single injection well for an extended period of time as discussed by the authors.
Abstract: Results of the recently completed Rocky Mountain I (RMI) underground coal gasification (UCG) field test have shown that the Controlled Retracting Injection Point (CRIP) process for UCG is capable of producing consistently high quality gas from a single injection well for an extended period of time. The RMI CRIP module was in operation for 93 days and gasified over 10,000 tonnes (11,023 tons) of coal, with an average dry product heating value of 253 kJ/mol (287 Btu/scf). The CRIP process, which utilizes a horizontally drilled injection borehole, has the advantage over vertical well process techniques in that it maintains oxidant injection low in the coal seam for optimal resource recovery, and provides a method for reignition of the coal in a different location when gas quality declines as the maturing reactor begins to interact with inert overburden. This report discusses the results of the RMI CRIP module, compares its performance with the simultaneously operated Extended Linked Well (ELW) module, and explains the behavior of the CRIP reactors with the aid of a model developed for describing UCG reactor dynamics for cases in which oxidant injection remains low in the coal. It is shown that both in terms of fundamental understandingmore » and practical application, the CRIP process for UCG in subbituminous and lower ranking coals has reached a level where the remaining technical uncertainties and risk to commercial development have been largely reduced. 6 refs., 8 figs., 4 tabs.« less
TL;DR: In this paper, a process for the reduction of nitrogen oxides in an effluent from the combustion of a carbonaceous fuel while minimizing the production of other pollutants is presented, which comprises introducing (most commonly by injecting) a nitrogen oxide reducing treatment agent into an effluence according to a nitrogen Oxides reducing treatment regimen under conditions such that the treatment agent is operating on the high temperature or right side of its nitrogen oxide reduction versus effluent temperature curve.
TL;DR: In this article, the effect of temperature, time, mineral matter and oxygen concentrations on low-rank coal has been investigated using synchronous fluorescence spectroscopy, showing that polyaromatic ring absorptions in these conditions occur in the 2, 3 range.
TL;DR: In this article, a model for the rapid devolatilization of individual coal particles is developed by analogy with a single-stage equilibrium flash distillation, and the model accurately correlates the yields of noncondensible gas and tar from bituminous coals over wide ranges of temperature and pressure.
Abstract: A model for the rapid devolatilization of individual coal particles is developed by analogy with a single-stage equilibrium flash distillation. In the theory, thermal depolymerization of the coal generates aromatic fragments that are widely distributed in size. Conditions for phase equilibrium determine the partitioning of these fragments into intermediates in the condensed phase, which ultimately form char and light gas, and into tar vapor, which escapes in a stream of light gases. Comparison with data shows that the model accurately correlates the yields of noncondensible gas and tar from bituminous coals over wide ranges of temperature and pressure. The predicted molecular weight distributions of tar are also in agreement with measured distributions, and the model yields a mechanistic basis for their observed insensitivity to temperature. The tendency to form lighter tar at higher pressures is also explained.
Patent•
27 Sep 1988TL;DR: In this article, a method of producing coalbed methane by injecting inert gas, such as nitrogen, through an injection well into the coal seam and recovering coal-bed methane from a production well(s) was proposed.
Abstract: A method of producing coalbed methane by injecting inert gas, such as nitrogen, through an injection well into the coal seam and recovering coalbed methane from a production well(s). Methane desorption from coal is achieved by reduction in methane partial pressure rather than by reduction in total pressure alone.
TL;DR: In this paper, it was shown that the coal seam methane content of a seam is not likely to exceed the methane sorption capacity of the coal determined at a temperature commensurate with that obtaining at the maximum burial depth.
TL;DR: In this paper, the effects of char formation temperature, conversion, coal particle size and char particle size on the rates of coal chars derived from three different bituminous coals were measured at 500 °C.
TL;DR: In this paper, the elemental compositions of coals from Fording, southeastern British Columbia, were examined using INAA and ICP spectrometry, and detailed elemental analyses were carried out for coal seams in two equivalent sections and also within selected coal seams.
TL;DR: In this article, 50 different chimney soot samples from house heating in the area of Bayreuth, Germany, were analyzed for PCDD/F and their isomer patterns were similar to those from municipal waste incinerators.
TL;DR: In this article, the tensile strength of two coals were measured in carbon dioxide and nonsorbing (helium) atmospheres up to pore gas pressures of 3.5 MPa, and it was shown that gas sorption produces no significant reduction in coal strength at the 95% confidence level.
TL;DR: In this paper, a technique whereby substantial portions of bituminous coal are extracted, non-destructively, is demonstrated by treating raw coal with N -methylpyrrolidone (NMP), and an ultraclean, coal-derived solid material with as little as 0.1% ash and containing no pyritic sulfur was derived by following the extraction step with precipitation of the coal-based material in water and subsequent filtration.
TL;DR: In this article, a 0.3 m internal diameter combustor was used for spouted, fluidized and spout-fluid bed combustion of three bituminous coals or coal rejects of differing ash contents.
TL;DR: In this article, the chemical and physical properties of pyrolysis products and their yields as a function of the processing conditions are discussed, including temperature, pressure, atmosphere, heating rate and coal type.
TL;DR: In this paper, the authors discuss the influence of the composition of fuel and temperature on the vitesse de destruction of NO, in particulier dans la deuxieme zone de combustion.
Abstract: Etude des reactions chimiques de NO, NH 3 , HCN au cours de la combustion etagee du lignite. Influence de la composition du fuel et de la temperature sur la vitesse de destruction de NO, en particulier dans la deuxieme zone de combustion
01 Jan 1988
TL;DR: In this paper, the rate of formation of acetylene, the most interesting product of coal pyrolysis in hydrogen plasma, is determined by heat transfer to coal and by the kinetics of pyrotechnics and homogeneous gas phase reactions.