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Show eo ., Soulh BeuI.h • b,W.ndoan • ~ ~ <40 Gas 0 •• i ~ -------- ~ 20 0 0 r. 0 r.r 0 eo c, Uddell d) t<ey.lone i ~ "0 i !f ~ 20 T emperalUfe, K Temperature, K Fig. 2. An evaluation of FLASHCHAIN predictions against transient weight loss (.) and tar yields (0) for atmospheric devolatilization for 4s at the indicated temperatures following heatup at roughly 3000 Kls. The 4 coal types are arranged in order of increasing rank from subbituminous through low volatile bituminous from parts a through d. 4 cases from the onset to the completion of devolatilization. Very good quantitative agreement is also apparent in the predicted tar yields. The evaluation of ultimate weight loss and tar yields for heating rates from 5 to 5000 Kls in Fig. 3a demonstrates a finn basis for extrapolations. These data are for heatup at the indicated rates to 1225 K, followed by aSs hold period at 0.1 MPa with 2 coals, an TIL #6 and a Iv bituminous. The predicted weight loss and tar yields from both coals are within experimental uncertainties throughout. For the TIL #6, tar yields double over this range of heating rate, incrementally increasing ultimate weight loss by almost the same amount. But there is virtually no enhancement with the low volatility coal. The predicted nitrogen evolution for the TIL #6 coal tests in Fig. 3a are evaluated in Fig. 3b. Total fractional nitrogen evolution appears along with the fractional tar-N after heating at 5 to 5000 Kls to 1225 K with aSs isotherma~ reaction period. The predicted volatile-N and tar-N are within experimental uncertainty at all heating rates except the fastest. However, this is probably not a flaw in the predictions because 5000 Kls is 4 |
