FUNDAMENTAL INVESTIGATION OF FUEL TRANSFORMATIONS IN PULVERIZED COAL COMBUSTION AND GASIFICATION TECHNOLOGIES
The goal of this project is to carry out the necessary experiments and analyses to extend leading submodels of coal transformations to the new conditions anticipated in next-generation energy technologies. During the first project quarter, a technical kick-off meeting was held on the Brown campus involving PIs from Brown (Hurt, Calo), BYU (Fletcher), and B&W (Sayre, Burge). Following this first meeting the current version of CBK (Version 8) was transferred to B&W McDermott and the HP-CBK code developed by BYU was transferred to Brown to help guide the code development in this project. Also during the first project year, progress was reviewed at an all-hands meeting was held at Brigham Young University in August, 2001. The meeting was attended by PIs Fletcher, Hurt, Calo, and Sayre, and also by affiliated investigators Steven Burge from McDermott and Prof. William Hecker from BYU. During the first project year, significant progress was made on several fronts, as described in detail in the previous annual report. In the current second annual report, we report on progress made on two important project tasks. At Brown University: (1) Char combustion reactivities at 500 C in air were determined for a diverse set of solid fuels and organic model compound chars. These varied over 4 orders of magnitude for the chars prepared at 700 C, and over 3 orders of magnitude for the chars prepared at 1000 C. The resultant reactivities correlate poorly with organic elemental composition and with char surface area. (2) Specially-acquired model materials with minute amounts of inorganic matter exhibit low reactivities that fall in a narrow band as a function of wt-% carbon. Reactivities in this sample subset correlate reasonably well with total char surface area. (3) A hybrid chemical/statistical model was developed which explains most of the observed reactivity variation based on four variables: the amounts of nano-dispersed K, nanodispersed (Ca+Mg), elemental carbon (wt-% daf), and nano-dispersed vanadium, listed in decreasing order of importance. Catalytic effects play a very significant role in the oxidation of most practical solid fuel chars. Some degree of reactivity estimation is possible using only elemental analyses of parent fuels, but only if correlative techniques make use of the existing body of knowledge on the origin, form and dispersion of inorganic matter in various fuel classes. During the past year at BYU, work focused primarily on renovation of the BYU high pressure drop tube reactor (HPDT). This work has included design and testing of a flat-flame burner that can be operated at high pressure. A high-temperature, high-pressure gas profile has been achieved within this high-pressure flat-flame burner (HP-FFB). Detailed descriptions of the design and testing of the HP-FFB are given in this report. In addition, continued char reactivity experiments in the high pressure thermogravimetric analyzer (HP-TGA) have been performed on chars produced at different pressures in the HPDT. Results of the HP-TGA reactivity studies on a high-volatile A bituminous (Pittsburgh No.8) char are that intrinsic char activation energy increases with pyrolysis pressure, and that the oxygen order is roughly 0.9. These results are different than previous research on chars produced at atmospheric pressure. These new data show that the rate constant decreases with increasing pyrolysis pressure. However, the hydrogen content of the new chars produced at elevated pressures was fairly high ({approx}2 wt. %, daf), and char samples produced at higher temperatures are desired. During the next project year, experimental work on oxygen reactivity at high pressure will continue at BYU, and on CO{sub 2} reactivity at high pressure at Brown University. Selected chars produced at BYU under high pressure conditions will also be used at Brown for reactivity studies.
- Research Organization:
- Brown University (US)
- Sponsoring Organization:
- (US)
- DOE Contract Number:
- FG26-00NT40815
- OSTI ID:
- 819435
- Resource Relation:
- Other Information: PBD: 1 Jan 2003
- Country of Publication:
- United States
- Language:
- English
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