Author: Bituminous Coal Research, Inc
Publisher:
Published: 1969
Total Pages: 290
ISBN-13:
DOWNLOAD EBOOK →Author: Henk Meuzelaar
Publisher: Springer Science & Business Media
Published: 2013-12-14
Total Pages: 426
ISBN-13: 1489936718
DOWNLOAD EBOOK →The past decade has witnessed major advances in our understanding of the chemical composition, structure, and reactivity of the complex organic-rich fossil matter known as "coal. " Nevertheless, important scientific questions concerning molecular weight distributions, degree of crosslinking, typical duster sizes, type of interconnecting bridges, the possible role of a "mobile phase," and the nature of organic sulfur forms remain topics of heated debate. Moreover, there appears to be a notable lack of consensus regarding the overall direction and goals of structural elucidation work. Is it worthwhile to study whole coal samples, or should we separate out the various, more or less well-defined, maceral and mineral constituents before attempting to describe the structural and compositional features of coal at the molecular Ievel? Second, should there be more emphasis on key structural features and average statistical parameters, or is it necessary to identify individual chemical structures in considerable detail? From the developments of the past decade it is clear that advanced spectroscopic techniques are playing an increasingly important role in resolving difficult questions with regard to the chemical structure and composition of coal. Moreover, it has become equally clear that no single spectroscopic approach can provide all the answers but multiple techniques need to be used in a highly integrated and synergistic manner.
Author:
Publisher:
Published: 1989
Total Pages: 218
ISBN-13:
DOWNLOAD EBOOK →This project consisted of three sections. In the first part, the physical cleaning of Ohio coal by selective flocculation of ultrafine slurry was considered. In the second part, the mild oxidation process for removal of pyritic and organic sulfur.was investigated. Finally, in-the third part, the combined effects of these processes were studied. The physical cleaning and desulfurization of Ohio coal was achieved using selective flocculation of ultrafine coal slurry in conjunction with froth flotation as flocs separation method. The finely disseminated pyrite particles in Ohio coals, in particular Pittsburgh No. 8 seam, make it necessary to use ultrafine ( -500 mesh) grinding to liberate the pyrite particles. Experiments were performed to identify the ''optimum'' operating conditions for selective flocculation process. The results indicated that the use of a totally hydrophobic flocculant (FR-7A) yielded the lowest levels of mineral matters and total sulfur contents. The use of a selective dispersant (PAAX) increased the rejection of pyritic sulfur further. In addition, different methods of floc separation techniques were tested. It was found that froth flotation system was the most efficient method for separation of small coal flocs.