Technical Paper Volume 90-106

Technical Paper Volume 90-106

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1915 edition. Excerpt: ...with regard to changes at ordinary temperatures. The results obtained by these investigators vary widely--from the statement that ' quite a large amount of water is produced in oxidation" to those of the authors who can find no water produced by their method of experiment. The third investigator found that in some cases very small amounts of water were produced and in others none whatever. The authors of this paper conclude that at ordinary temperatures coal undergoing oxidation produces no water. The authors have determined, too, that the change in weight of the coal is less than that of the water removed from the coal when drying takes place in an inert atmosphere. Others b have noted this discrepancy. A possible explanation is that the discrepancy results from the absorption of gas by the coal on drying. PREVIOUS INVESTIGATIONS. Porter and Ovitz have shown that hydrogen escapes from coal in the form of methane when the coal is exposed after mining. Later experiments by Katz d show that this gas is absorbed by the coal, so that the manner of absorption is physical rather than chemical, and that hydrogen should be differentiated from that present as part of the coal substance. Consequently, this change need not be considered here. Taffanele exposed freshly made coal dusts to mine air. Analyses showed that the percentages of hydrogen, nitrogen, and volatile matter changed very little when computed on an ash-free basis. The oxygen increased and the carbon decreased. There was no evidence of changes in the absolute amount of hydrogen in the coal. In a further study of changes in natural dusts, as they occur in the mines, Taffanel/ says: "The carbon and hydrogen contents are diminished by the alteration; one must particularly more

Product details

  • Paperback | 206 pages
  • 189 x 246 x 11mm | 376g
  • United States
  • English
  • black & white illustrations
  • 1236872266
  • 9781236872265