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This study aims to investigate the compositional characteristics of aromatic hydrocarbons extracted from coals and to describe how the sulfur content influences the…
This study aims to investigate the compositional characteristics of aromatic hydrocarbons extracted from coals and to describe how the sulfur content influences the properties of coals and whether widely accepted maturity parameters are suitable for medium- to high-sulfur coal.
Four samples of medium- to high-sulfur coal were obtained from Fenxi, Shanxi Province, and studied using gas chromatography and gas chromatography–mass spectrometry (GC-MS).
The GC-MS results showed that there were five series of compounds were identified in the aromatic fractions: naphthalenes, phenanthrenes, oxygen-containing compounds, biphenyls and sulfur-containing compounds. The substituent group was mainly methyl. The content of dibenzothiophenes was high, which was attributed to their high thermodynamic stability. The presence of sulfur reduced the content of oxygen-containing compounds. A depositional environment that facilitated the formation of organic sulfur compounds led to a higher content of naphthalenes.
The development of methods for removing organic sulfur compounds would benefit from a study of their nature, which would be important for improving the use of coal.
Manufacturing methods of white mineral oils are described, together with a summary of their major use areas. Recent toxicological studies using white mineral oils of various categories are covered. A summary of the current acceptable daily intake levels for such substances is included.
Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the U.S. National Advisory Committee for Aeronautics, and publications of other similar research bodies as issued
So‐called emulsifiers do many things. Although the addition of an emulsifier to some mixtures does emulsify them, the emulsification of other mixtures may require other ingredients as well. Some existing emulsions may actually be broken by the same emulsifier; others may be broken and converted to a new emulsion; and some materials may be changed in firmness, viscosity, wettability or other properties even when no emulsion is involved. To make matters even more complicated, the effect of a given emulsifier in a given system may vary dramatically with temperature. For example, the most familiar of emulsifiers, egg yolk, causes most of the difference seen between a pastry dough and a cake batter or between pastry and cake: at mixing temperature it causes the difference between a plastic solid and a pourable liquid, whereas at baking temperature it causes the difference between a rigid, friable solid and an elastic solid. Emulsifiers are used in a very wide range of industrial processes, from oil‐drilling to paint‐making and printing. However their use in the manufacture of food and beverages clearly requires the most stringent standards of identity. Under current UK legislation, food emulsifiers are regulated by the same statutory instrument as the so‐called stabilisers. The difficult problem of definition is approached on the basis of function :—
The total utilisable resources of carbon in the biosphere are enormous by any standards. In the atmosphere alone there are about 700 billion tons of carbon as carbon dioxide and in the oceans there are stored 35,000 billion tons of available carbon dioxide. These two reserves alone amount to about four times the estimated total reserves of carbon in the form of coal and oil. The essential difference between these alternative sources of carbon is that whereas the carbon in the biological cycle is being continuously circulated in a system in which the total amount of carbon remains sensibly constant (there is a further 30,000 billion tons of carbon in the form of biological organic matter), the carbon in the form of coal and oil reserves are being rapidly depleted with consequent escalating cost and the lifetime of this source of chemicals and energy is variously estimated as being between 20 and 50 years.
This publication is a record of a systematic study by records of pressure as a function of time of the cooling effect of the walls of a closed metal vessel in which the explosion of a mixture of air and hydrocarbons is obtained by an electric spark.
IN A TECHNICAL PAPER at the 1966 Conference of the American Society of Tool and Manufacturing Engineers, L. D. Wells considers practical ways of evaluating cutting fluids…
IN A TECHNICAL PAPER at the 1966 Conference of the American Society of Tool and Manufacturing Engineers, L. D. Wells considers practical ways of evaluating cutting fluids. Some general agreement exists that the most satisfactory method is that of tool life study based on either complete failure or some agreed amount of wear. This is, however, relatively costly in terms of both time and material and hence many workers have developed accelerated bench tests using, for example radioactive tracers for wear determination or alternatively measuring a single property such as cooling power of a fluid. The author argues that as machining is a complicated process which involves plastic deformation, friction, wear and heat transfer it is unlikely that an accelerated test can yield valid results.
Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued.
Lubricants impact on the environment at all stages of production, usage and disposal. The awareness and concern over the usage of petroleum‐based products and their impact…
Lubricants impact on the environment at all stages of production, usage and disposal. The awareness and concern over the usage of petroleum‐based products and their impact on the environment have created an opportunity to produce environmentally acceptable lubricants from agricultural feedstocks. A new class of bio‐based esters derived from vegetable oils that exhibit excellent low temperature flow properties and oxidation stability are discussed. One of the major advantages of bio‐based synthetic esters in better performance at a lower cost compared to synthetic esters. This is possible due to recent advances in the biotechnology of vegetable oils and the chemical modifications that could be applied to convert these natural esters into high performance biolubricants.
The petroleum shortage of the 1970s (1984 is the tenth anniversary of the OPEC embargo!) motivated tremendous interest in finding alternative raw materials for chemicals…
The petroleum shortage of the 1970s (1984 is the tenth anniversary of the OPEC embargo!) motivated tremendous interest in finding alternative raw materials for chemicals. Indeed, in 1975 it was predicted that by 1990, huge and expensive coal gasifiers would be producing CO and hydrogen for synthesis gas, from which the chemical industry would derive many of its raw materials. In 1983 it was apparent that this prediction was far from accurate. To be sure, eventually there will be a shift from petroleum to coal, but it most surely will not be before the end of the century and perhaps not even then. Coal will, however, continue to find increasing use as an energy source. The vast amount of research that has been done on converting synthesis gas to chemicals will continue, although with considerably less intensity. When the time comes, the shift will be made. But that time will be delayed as far as possible because the shift will require tremendous capital investment. Coal gasifiers can cost as much as US$500,000, and the return on such an investment must be assured before it is made. Certainly, coal is a cheap raw material. Thus, its use for chemicals represents a trade‐off between a cheap raw material and a very high capital investment.