Role of preasphaltenes in coal conversion reactions. First quarterly report, year two

The plans for the second year called for application of analytical methods developed in the first year to the elucidation of the role of preasphaltenes in coal conversion processes. Prior experiments with fresh and weathered coals, however, had provided strong indications for the existence of a marked influence of weathering processes on coal structure and reactivity in general and on the production of preasphaltene-rich, short-contact-time (SCT) pyrolyzates. In this report SCT pyrolysis experiments on coals of known weathering status are discussed and results presented. A review of the more recent literature on technologically relevant aspects of coal weathering is also included. 26 references, 8 figures

Role of preasphaltenes in coal conversion reactions. Second quarterly report, year two

The plans for the second year in the present contract called for application of analytical methods developed in the first year to the elucidation of the role of preasphaltenes in the coal conversion processes. As introduced and discussed in the last quarterly report, recent experiments have demonstrated the necessity of also studying the influence of weathering processes on coal structures and reactivity especially in regard to the production of preasphaltene-rich, short contact time (SCT) pyrolyzates. In this report we review and further develop some of the results presented in the last quarterly report as well as new information obtained in the second quarter. These results and their implications to initial coal structure and the role of preasphaltenes are discussed in respect to the following four tasks: (1) Study of the effects of laboratory weathering on the Free Swelling Index (FSI), sample weight, calorific value and ASTM proximate analysis on hvb Hiawatha coal. (2) Thermogravimetry (TG) and Derivative Thermogravimetry (DTG) of fresh and weathered hvb coal samples. (3) Pyrolysis mass spectrometry (Py-MS) analysis of fresh and weathered hvb coal samples and detailed examination of weathering effects. (4) Py-MS comparison of vacuum and pyridine extracts and SCT tubing bomb reactor products from fresh and weathered coals. 7 references, 11 figures, 2 tables