Role of char during reburning of nitrogen oxides. Seventh quarterly progress report, April 1, 1995--June 30, 1995
- Univ. of Mississippi, University, MS (United States)
- Kansas State Univ., Manhattan, KS (United States)
The progress in this quarter includes four parts. In the first segment, the implications of our data reported in the List quarter are discussed further. BET N{sub 2} surface area does not seems to be the only contributing factor to the remarkable activity of lignite char during reburning, and chars of different origins probably have different controlling steps in the overall surface reaction mechanisms. Unlike NO reduction in the gas phase, oxygen inhibits the heterogeneous mechanisms. The second part of this report justifies the use of our laminar flow reactor system for the measurement of reaction rate. Dispersion model is used in the analysis. An expression relating the rate constant with the experimentally obtainable NO conversion for our flow reactor have been derived. Rates of NO/char reaction for six series of experiments have been measured over the temperature range 800 to 1100{degrees}C. These six series of experiments have been conducted with two different chars, one bituminous coal char and one lignite char, and three different levels of feed NO concentrations, 200, 400 and 1000 ppm. Results from the comparison of char activities suggest that, in the absence of O{sub 2} and CO{sub 2}, the origin of char is not a significant factor for NO reduction. The CO/CO{sub 2} ratio in the products is higher than one under all test conditions, but the ratio increases with increasing feed NO concentrations. Recoveries of oxygen form the lignite char at temperatures above 1050{degrees}C is higher than 1 indicating gasification of organic oxygen in the char. Surface areas of selected chars after devolatilization and after reburning have been analyzed by BET in N{sub 2}. Results indicated char surface area changes after reburning, which is caused either by the higher temperature of reburning or by surface reaction.
- Research Organization:
- Mississippi Univ., University, MS (United States). Dept. of Chemical Engineering
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG22-93PC93227
- OSTI ID:
- 155540
- Report Number(s):
- DOE/PC/93227-T6; ON: DE96003309; TRN: 96:000536
- Resource Relation:
- Other Information: PBD: 11 Aug 1995
- Country of Publication:
- United States
- Language:
- English
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