Showing papers on "Coal published in 1979"

Physical and chemical properties of fly ash from coal-fired power plants with reference to environmental impacts

Abstract: Interest in coal residue research has recently been increased with anticipated increased dependence on coal as a source of energy. United States coal reserves are estimated at 3.6 trillion metric tons, from which 396 billion metric tons can economically be mined (Swanson et al. 1976). United States electric power utilities consume from 60 to 65% of the amount of coal produced (Brackett 1973). In 1974, the power industry utilized approximately 400 million tons of coal (Ash at Work 1975). The magnitude of trace element mobilization into the environment from fossil-fuels is substantial and is comparable to that originating from major sedimentary cycles such as river flows and natural sediments (Bertine and Goldberg 1971). Consequently, increasing regulatory measures have been imposed on power industries by federal and local authorities restricting the amount of coal residue entering the atmosphere.

Generating electricity from coal in situ

Abstract: The system of the invention comprises a two well system of gasifying coal in situ wherein the generated gas stream is directed to a gas separator, which, in turn separates hydrogen and carbon monoxide into separate streams. Hydrogen is directed to one type of fuel cell and carbon dioxide is directed to another with the resultant generation of electricity. The method of the invention comprises establishing two wells into an underground coal deposit with a reaction zone in fluid communication with the wells. Coal is gasified both in oxidizing and reducing environments, with the produced gas stream separated into its component parts. Combustible gases are directed to fuel cells with the resultant generation of electricity.

An introduction to coal technology

Abstract: Origins, Formation, and Properties of Coal: Origins and Formation. Compositions. Classification. Physical Properties. Chemical Properties. Behavior at Elevated Temperatures. The Action of Solvents on Coal. Upgrading, Handling, and Processing of Coal: Benificiation, Cleaning, Drying, and Briquetting. Transportation and Storage. Combustion. Carbonization and Tar Processing. Gasification. Coal Liquefaction. Environmental Aspects of Coal Utilization. Subject Index.

Pulverized-coal combustion and gasification

Abstract: This book presents chapters that contain information on the following topics: homogeneous gas-phase equilibrium; multicomponent conservation equations; turbulence models; gas-phase chemical kinetics; models of turbulent combustion; radiative heat transfer in a pulverized coal flame; gas-particle flow; general characteristics of coal; heterogeneous reactions of char and carbon; volatiles combustion; methane oxidation; mechanisms and kinetics of pollutant formation during reaction of pulverized coal; modeling pulverized-coal reaction processes; modeling one-dimensional systems; modeling multidimensional systems; and a generalized pulverized-coal reactor model.

Morphologies and origin of elemental carbon in the environment.

Abstract: Carbon particles extracted from sediments collected by box coring from southeastern Lake Michigan were compared with carbon particles extracted from oil, coal, and wood fly ash. Sediments deposited after 1900 contained coal, oil, and wood carbons; older sediments contained only wood carbon.

Progress in biomass conversion

Abstract: This book reviews the long-range potential of biomass. It also discusses how biomass could replace petroleum and natural gas through different processes and under different circumstances, and at what price and to what extent. It provides a comparison with alternative resources, including coal and petroleum, and taking into consideration such problems as corrosion and erosion....These papers provide a demonstration of how technical feasibility can be distinct from economic viability and how changes in one can affect the other. The contents discussed are: Hydroprocessing of Biomass Tars for Liquid Engine Fuels; Fuel Characteristics of Wood and Nonwood Biomass Fuels; Factors Influencing Dilute Sulfuric Acid Prehydrolysis of Southern Red Oak Wood; The Energy Costs of Increased Organics Recovery for Chemical By-Products in Kraft Pulp Mills; Microeconomic Approaches to Biomass Fuel Pricing; Fuel Characteristics of Selected Species of Beached Logs in Southeastern Alaska; An assessment of the Costs and Benefits of Recovering Logging Residue for Energy Use; Review of Biomass Gasification Technology; and Index.

Process for consolidating coal and/or rock in mines

Abstract: 1. A process for consolidating coal and/or rock in mining by the injection of a dispersion which hardens after its entry and which comprises a magnesium chloride solution, calcined magnesite, highly-active magnesium oxide, bentonite and water, characterized in that an amount of more than 2.5 % by weight of hyghly-active magnesium oxide is admixed and that, additionally, a chemical substance which retards setting is added.

Thermal, mechanical, and physical properties of selected bituminous coals and cokes

Abstract: Thermal, mechanical, and physical properties of virgin and heat-treated Pittsburgh seam coal were determined as part of a comprehensive study of combustion of monolithic coal block The information was sought to help characterize pyrolysis and combustion processes in underground coal mine fires, but should also prove useful in the study of in situ and surface coal gasifiers Measured properties include thermal conductivity, specific heat, thermal expansion, density, compressive and tensile strength, porosity, and permeability The transport property data were obtained (when feasible) in 2 mutually perpendicular directions of the anisotropic virgin coal material, and coal samples carbonized for 5 hr at temperatures of 350 C, 475 C, 500 C, 650 CC, and 850 C Other coals (Pocahontas No 3, Sewell, and Illinois No 6 seams) were investigated for porosity and relative permeability 49 references

Coal-water slurry and method for its preparation

Abstract: A pipeline pumpable coal-water slurry having a novel combination of coal particles and carrier water is prepared by a method wherein the particle sizes and their distribution are controlled in accordance with a particle size distribution formula which is especially beneficial for providing a novel coal compact with a minimum amount of void space between particles and a maximum amount of particle surface area with an advantageous amount of colloidal sized particles present. These features combine to enhance the dispersing effects generated by electrolytes and/or dispersing agents selected and added to the coal compact and/or slurry to provide a near maximum zeta potential to the particles in the slurry and to provide low viscosity to the resulting yield pseudoplastic coal-water slurry. Brookfield viscosities obtained, e.g. 1000 cps, or less, at 60 rpm with 75 wt. % coal, dry basis, make the coal-water slurry especially advantageous for transport by pipeline over long distances. The coal-water slurry can be provided at a high coal content so that the slurry can be burned directly without need for dewatering at its destination.

Effects on prolific petroleum source rocks and major coal deposits caused by sea-level changes

Abstract: THE nature and abundance of planktonic organic matter—the main source of crude oil—and moreover its preservation in sediments are affected by sea-level changes. Deposition of paralic coals might be also influenced. It is shown here that these considerations would explain large accumulations of coal or petroleum source rocks over relatively short periods of time.

H 2 S incorporation in coal precursors: origins of organic sulphur in coal

Abstract: Of the forms of sulphur in coal—organic, pyrite, and sulphate—the organic sulphur component is the most difficult to remove before coal can be used. Organic sulphur, which is generally regarded as sulphur in a carbon–sulphur linkage, can represent >50% of the total sulphur found in some coals1. We describe here an investigation into the origin of the organic sulphur in the coal-forming sequence which includes: peat → lignite → bituminous coal → anthracite coal. Because of the chemical heterogeneity and associated chemical complexity of working with either bituminous or anthracite coals, the earliest stage of coal formation, that is the peat-forming stage, was studied. Modern progenitors of coal from the Okefenokee Swamp were studied, as these peat-forming systems closely approximate ancient systems that eventually gave rise to huge coal deposits2–4. While amino acid sulphur from source plants is an important progenitor of organic sulphur in peat, it was found that H2S can react with the organic matter in peat to produce organic sulphur—a source of organic sulphur in coal that has not been previously discussed.

Product compositions and formation kinetics in rapid pyrolysis of pulverized coal—Implications for combustion

Abstract: Previous work in this laboratory on the rapid pyrolysis of a lignite and a bituminous coal has been extended to include time-resolved measurements of volatiles composition. Approximately monolayer samples of small coal particles supported in a metal screen were rapidly heated in helium to a desired temperature, held there for a desired time, and then rapidly cooled. Volatiles were rapidly diluted and quenched, and all products were collected. Sample weight loss and product compositions were determined as a function of heating rate (270-10,000°C/s), peak temperature (up to 1100°C), holding time at peak temperature (0–30s), pressure (0.0001–100 atm), and particle, size (74–1000 μm). Volatile yields increase montonically as temperature increases, with the evolution of different products or groups of products occurring in sequential but overlapping temperature intervals. The lignite volatiles are dominated by CO, CO2 and H2O, while the main volatiles from the bituminous coal are tar and light hydrocarbons. Heating rate has negligible effect on total yields or product distributions from either coal over the range studied. Pressure and particle size have little effect on product yields from the lignite. In contrast, for the bituminous coal, increases in pressure or particle size result in less tar and more char and hydrocarbon gases, apparently reflecting mass transport limitations and the occurrence of secondary reactions within or on the coal particles. The kinetics of the evolution of different products from the lignite is successfully modeled by one, two or three first-order decomposition reactions. For bituminous coal, a similar model which includes evaporation and diffusion of tar along with pyrolytic and secondary reactions is found to be consistent with the observed behavior. Use of the data to calculate the heating value and surface flux of volatiles under conditions pertinent to pulverized coal combustion indicates, in agreement with previous work, that combustion on the particle surface may in some cases precede the occurrence of a volatiles flame away from the surface.

The distribution and isotopic composition of sulfur in coals from the Illinois Basin

Abstract: The delta 34 S values of massive pyrite, disseminated pyrite, and organic sulfur from five major Illinois Basin coals have been determined. Disseminated pyritic and organic sulfur were chemically removed from banded ingredients and whole coal samples prior to isotopic analysis. Quantitative extraction of sulfur from vertical coal columns indicated that disseminated pyrite content varies greatly when compared to that of organic sulfur. Individual coal samples were classified as high or low sulfur based on organic sulfur content. High sulfur coals (>0.8% organic sulfur by dry weight) exhibited a wide range of delta values for organic sulfur (--8 to +15ppm), whereas low sulfur coals showed a narrow range (+5 to +13ppm). The isotopic ratio of disseminated pyritic sulfur exhibits large variations when compared to organic sulfur. The delta 34 S for organic sulfur in all three banded ingredients from the same coal sample are very similar. The delta 34 S and content of organic sulfur from vitrain and attrital coal in a high and low sulfur coal exhibit a linear trend of increasingly heavier delta values with decreasing sulfur content. This suggests the mixing of two isotopically distinct sources in the organic sulfur.Whole coal organic sulfur and massive pyrite from the same column exhibit little variation in delta 34 S (generally <10ppm) in comparison to their overall regional range, (24ppm and 40ppm, respectively). A linear relationship exists between organic and massive pyritic sulfur (delta 34 S mp = +1.1 delta 34 S or --4.8ppm) for high sulfur coals. This and additional evidence has been employed to construct a model describing the source and pathways of sulfur incorporation in high and low sulfur coals. Calculations based on this model indicate that an average of about 63 percent of the organic sulfur in high sulfur coals was contributed by bacterially reduced sulfate, whereas only about 13 percent was contributed by the same source in low sulfur coals. The other major source of organic sulfur in coals was plant-assimilated sulfur.

Apparatus and method for solar coal gasification

Abstract: Apparatus for using focused solar radiation to gasify coal and other carbonaceous materials. Incident solar radiation is focused from an array of heliostats onto a tower-mounted secondary mirror which redirects the focused solar radiation down through a window onto the surface of a vertically-moving bed of coal, or a fluidized bed of coal, contained within a gasification reactor. The reactor is designed to minimize contact between the window and solids in the reactor. Steam introduced into the gasification reactor reacts with the heated coal to produce gas consisting mainly of carbon monoxide and hydrogen, commonly called "synthesis gas", which can be converted to methane, methanol, gasoline, and other useful products. One of the novel features of the invention is the generation of process steam at the rear surface of the secondary mirror.

Process for removal of sulfur and ash from coal

Abstract: A process for reducing the sulfur and ash content of coal wherein coal particles are treated in an aqueous slurry with a minor amount of hydrocarbon oil to form coal-oil aggregates. The coal-oil aggregates are separated from ash and mineral matter in the slurry by dissolved gas flotation. Optionally, the coal particles may be treated with a conditioning agent prior to the aggregation step. Recovered coal particles comprise a substantial part of the feed carbon values.

China: an overview

Abstract: China's coal production exceeds 600,000,000 tons annually. Now entering a period of dramatic expansion, China promises to continue as one of the world's largest coal producers. While 96% of China's coal production is currently from underground mining, only 30% of this total output is from fully mechanized operations. Only one sixth - under 20% - of China's coal is currently processed in coal preparation plants. It is the stated obtective of the Chinese coal industry to significantly increase the percentage of operations using fully mechanized longwall retreat systems as well as to steadily increase the percent of coal that is cleaned through preparation plants in China. In 1978 alone, China purchased approximately 100 complete longwall systems from numerous Western manufacturers. It is obvious that the obcective is to test as many different Western mining systems as possible to enable the Chinese to collect sufficient data to choose the equipment in the future which will best help them reach their ambitious production goals. A significant move is underway to build and develop the needed coal preparation facilities to increase significantly the amount of coal cleaned. The immediate objective is to increase the amount of coal cleaned to 30% of total production.more » The estimated probable coal reserves in China total about 1,500,000,000,000 metric tons. Proven reserves are 600,000,000,000 tons.« less