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Title: EFFECT OF HEATING RATE ON THE THERMODYNAMIC PROPERTIES OF PULVERIZED COAL

Technical Report ·
DOI:https://doi.org/10.2172/807239· OSTI ID:807239

This semi-annual technical progress report describes work performed under DOE Grant No. DE-FG22-96PC96224 during the period March 24, 1999 to September 23, 1999 which covers the last (sixth) six months of the project. During this reporting period, extraction of devolatilization time-scales and temperature data at these time-scales analyzing the high-speed films taken during the experiments was complete. Also a new thermodynamic model was developed to predict the heat transfer behavior for coal particles subjected to a range of heating rates using one approach based on the analogy of polymers. Sensitivity analyses of this model suggest that bituminous coal particles behave like polymers during rapid heating on the order of 10{sup 4}-10{sup 7} K/s. At these heating rates during the early stages within the first few milliseconds of heating time, the vibrational part of the heat capacity of the coal molecules appears to be still frozen but during the transition from heat-up to devolatization, the heat capacity appears to attain a sudden jump in its value as in the case of polymers. There are few data available in the coal literature for 10{sup 2}-10{sup 3} K/s obtained by UTRC in their previous studies. These data were obtained for a longer heating duration on the order of several seconds as opposed to the 10 milliseconds heating time in the single particle experiments discussed above. The polymer analogy model is being modified to include longer heating time on the order of several seconds to test these data. It is expected that the model might still do a good job in the case of these larger heating time but very low heating rate experiments. Completion of the numerical analysis of the experimental data and preparation of the final report are in progress.

Research Organization:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
Sponsoring Organization:
US Department of Energy (US)
DOE Contract Number:
FG22-96PC96224
OSTI ID:
807239
Report Number(s):
FG22-96PC96224-06; TRN: US200304%%464
Resource Relation:
Other Information: PBD: 2 Nov 1999
Country of Publication:
United States
Language:
English