Nitration of polynuclear aromatic hydrocarbons in coal combustors and exhaust streams
Regarding PAH preparation, our efforts this quarter were directed at identifying the operating conditions in the laboratory furnace that clearly resolve primary devolatilization from secondary pyrolysis. In previous studies, pristine tars from primary devolatilization were prepared in the radiant coal flow experiment with a furnace length of only 5 cm. Tars at various extents of secondary pyrolysis were generated in a hot-zone of 12.5 cm. For this project we decided to try to prepare both kinds of PAH in the 12.5 cm hot zone. Preliminary screening surveys showed that, among the dime possible ways to compensate for the longer furnace tube, only lowering the fumace temperature is really effective. Lowering the loading from its already low value of 300 No./cm[sup 3] is inconsequential, and raising the gas velocity to lower residence times in the longer hot zones causes deposition problems. The coal jet undergoes the transition to turbulence in less than 12 cm for entrainment velocities greater than 1 cm/s. By the end of the quarter, it was clear that the best value for primary devolatilization studies will fall within the range of 1 150 to 1400 K. But at present we are still not completely satisfied with the resolution of primary devolatilization. As intended, the tars collected at short residence times are completely soluble in tetrahydrofuran (THF), indicating that no soot is present so no secondary pyrolysis has occurred. But at residence times long enough to attain ultimate primary devolatilization yields, some soot is present. We will make our final choice early in the next quarter, then begin to collect an inventory of primary devoatilization tars for subsequent detailed characterization.
- Research Organization:
- Stanford Univ., CA (United States). Dept. of Civil Engineering
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-91PC91284
- OSTI ID:
- 6491104
- Report Number(s):
- DOE/PC/91284-2; ON: DE93014957
- Country of Publication:
- United States
- Language:
- English
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Nitration of polynuclear aromatic hydrocarbons in coal combustors and exhaust streams
Nitration of polynuclear aromatic hydrocarbons in coal combustors and exhaust streams. Quarterly report, April 1, 1992--June 30, 1992
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COAL
COMBUSTION
DEVOLATILIZATION
PYROLYSIS
POLYCYCLIC AROMATIC HYDROCARBONS
CHEMICAL PREPARATION
PROGRESS REPORT
AROMATICS
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
DECOMPOSITION
DOCUMENT TYPES
ENERGY SOURCES
FOSSIL FUELS
FUELS
HYDROCARBONS
MATERIALS
ORGANIC COMPOUNDS
OXIDATION
SYNTHESIS
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