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Total Pages : 5 pages
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Book Synopsis Fundamental Studies of Coal Liquefaction. Quarterly Report No. 5, October 1, 1992--January 1, 1993 by :
Download or read book Fundamental Studies of Coal Liquefaction. Quarterly Report No. 5, October 1, 1992--January 1, 1993 written by and published by . This book was released on 1993 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results for the control run for a single particle are shown in Figure 1. The figure, which includes other thermolytic data for Illinois No. 6 coal, shows that the particle was stable in size to around 440°C. At that point it contracted very rapidly to about half its size over the next 15°. Also shown are data for the same coal from SRI's field ionization mass spectrometer (FIMS), in which case a sample of the coal is heated at 2.5°C/min from ambient to 500°C and the effluent is swept into mass spectrometer. The evolution of the coal volatiles is reflected by accumulated ion count with increasing temperature, and is presented in the figure as the fraction of total volatiles. As the figure shows, the abrupt increase in volatility corresponds very closely to the equally abrupt reduction in particle size. The weight average molecular weight profile from the FIMS work is also in the figure, and shows that the coal experiences a simple loss of volatiles of increasing molecular weight up to around 440°C. At that point pyrolysis and fragmentation come about, reflected in the quick reversal and decline in molecular weight. The high rate of volatility and shrinkage are clearly associated with this second stage in the pyrolytic process. These results are further in line with the account of Eser et al. (1991) who found in studies of Illinois No. 6 coal in a high pressure microdilatometer that the coal contracted by about 40% in the same region of temperature at heating rates of around 20°C/min. At higher heating rates the contraction was followed by a swelling. Finally, in our cell work we observed the deposition of tar in the diamond windows starting at around 350°C.