ISSN:0090-8312    

DOI:10.1080/00908317708945971

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Widespread interest in reducing the sulfur content of coal has increased the need for chemical determinations of the forms of sulfur: sulfate, pyritic, and organic. The proper use and application of methods of determining the forms of sulfur in coal and coal refuse, including interpretation of results, can pose serious problems; consequently, a report and discussion of current methods of analysis, including instrumental methods, should prove helpful. A review of the evolution of current ASTM sulfur standards is presented, and a critical examination is made of problems associated with the determination of the varieties of sulfur in coal. Results of instrumental, oxidation, and reduction methods are given to show that close agreement among the three can be obtained and that calculation of organic sulfur by difference is reasonably accurate. The dangers of applying these methods to the determination of forms of sulfur in coal-related materials (e.g., high-ash fractions from float-sink procedures) are illustrated by data from a washability study of 64 coals.

ISSN:0090-8312    

DOI:10.1080/00908317708945972

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Background and current state of knowledge with regard to hazardous and toxic air pollutants are reviewed. Secondary pollutants formed from the interaction of primary pollutants are likely, to be the major hazard. Their formation and biological effects are discussed. The need for a uniform strategy and a realistic cost/risk/benefit analysis of the problem is pointed out.

ISSN:0090-8312    

DOI:10.1080/00908317708945973

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Organically combined sulfur and inorganic sulfides comprise nearly all the sulfur found in coals. Pyrite and marcasite are the dominant iron sulfides in coals. The wide range of sizes and forms they exhibit results from the different geochemical environments that affected their formation in the coals during their long history. Other sulfides that have been reported are sphalerite, galena, chalcopyrite, and arsenopyrite. Sulfate materials are much less common in fresh coal samples, but a variety of ferrous and ferric sulfates form when the ferrous sulfides are oxidized. Removal of inorganic sulfur from coal by standard specific gravity techniques is, at best, incomplete.

ISSN:0090-8312    

DOI:10.1080/00908317708945974

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Recent advances in the design of wireline logging equipment (initially designed for the petroleum industry) and improved computerized analyses of these logging measurements provide reliable information for coal evaluation and associated mining operations. Properly applied well log analysis concepts allow a continuous, in-situ evaluation of coal seams including thickness, moisture, and ash content. Formation strength parameters (elastic rock constants such as Bulk Modulus, Young's Modulus, Shear Modulus, and Poisson's Ratio) can be determined not only for the roof and floor rock of the coal seam, but for the entire over-burden as well. The present discussion presents some field experiences with these techniques.

ISSN:0090-8312    

DOI:10.1080/00908317708945975

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Kerogen is the most abundant form of organic carbon on the earth and plays a very important role in the formation of hydrocarbons. In view of its vast abundance and importance, relatively little is known about its origin, method of formation or structure. Certain kerogens are known to have been formed from the remains of algae, bacteria, diatoms, fungi, and other microorganisms. In an attempt to get more information on these types of kerogens, we have isolated the insoluble organic matter of a recently-deposited algal mat from Laguna Mormona, Baja California. It has been isolated using techniques similar to those used in the isolation of kerogen from ancient oil shales and sediments. The kerogen-!ike residue from the algal mats has been exhaustively extracted to remove soluble lipid material and divided into two portions, one of which was saponified. The residues were further degraded by stepwise alkaline potassium permanganate oxidation. The major oxidation products identified included: αω-dicar-boxylic acids (range C8-C11). normal mono-carboxylic acids (range C110-C31); isoprenoid acids (range C11-C20); and mono-methyl branched acids (range C12-C18). The initial oxidation products were dominated by normal mono-carboxylic acids but with increasing time of oxidation the αω-dicarboxylic acids dominated

ISSN:0090-8312    

DOI:10.1080/00908317708945976

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Lignite may be hydrogenated to a Jow-sulfur, low-ash, heavy fuel oil in the absence of added catalysts by use of synthesis gas and the moisture in the coal as the reducing agent. Conversions of 90-94% and oil yields near 60% (moisture, ash-free basis) have been obtained routinely at temperatures of 425-450°C and pressures of 3000-4000 psig. These conversions and oil yields are higher than those obtained with hydrogen at the same conditions. The effectiveness of carbon monoxide in hydrogenating lignite is, in part, due to the presence of the carbonates of the alkali and alkaline earth metals which react with carbon monoxide, in the presence of water, yielding formates, the active reducing agents.

ISSN:0090-8312    

DOI:10.1080/00908317708945977

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

摘要:

Based on our present knowledge, the only long-term practical solution to sustaining a national economy on natural gas is to convert a major source of continuously renewable nonfossil carbon to substitute natural gas that is interchangeable with, or can be substituted for, natural gas. The most promising source of this carbon is land- and water-based biomass produced from solar energy by photosynthesis. An assessment of this concept is presented in this paper, and the major problems encountered in the development of the technology are reviewed. The technology for biomass production and conversion is sufficiently advanced so that break-throughs and discoveries of a fundamental nature are not required. Special emphasis is given to the importance of system design, biomass production, biomass conversion to SNG, economics, and energetics. A concept for the Net Energy Production Ratio of fully integrated systems is also presented. After suitable development, the commercialization of an SNG industry using low-cash-value, high-fuel-value biomass raw materials will probably be economically attractive. It is essential to start a full-scale development program now so that the technology is ready for use before fossil fuel depletion causes even greater energy supply problems.

ISSN:0090-8312    

DOI:10.1080/00908317708945978

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor

ISSN:0090-8312    

DOI:10.1080/00908317708945979

出版商:Taylor & Francis Group    

年代:1977

数据来源: Taylor