MODELING CHAR OXIDATION AS A FUNCTION OF PRESSURE ...

Table A.2. Measured Centerline Reactor Temperatures
Condition number #1 #2 #3 #4
Condition name CH 4 fuel-rich CH 4 fuel-lean CO fuel-rich CO fuel-lean
Height Above Burner Gas Temperature Profile (K)*
0.25 1542 1677 1650 1718
0.50 1637 1628 1687 1670
0.75 1640 1608 1703 1647
1.00 1644 1592 1696 1630
* Measured along reactor centerline, corrected for radiation loss.
Procedures and Apparatus
Char Preparation
Coal particles were injected through the flame, reacted, captured by a suction
probe at a certain distance away from the injection point, quenched by nitrogen in the
probe tip, and separated from the soot and the gas in a virtual impactor and cyclone
system. The distance between the injection point and the suction probe (called the
reaction length or sampling height) was set to one inch for most of the experiments,
corresponding to a residence time of 14 ms. Studies of Koonfontain char were also made
at the methane fuel-lean condition at increased residence times by sampling at heights of
2, 4, and 6 inches (corresponding to about 25, 44, and 63 ms, respectively).
The particle residence time as a function of sampling height was measured for
several different coals with a high-speed video camera by Ma (1996). The residence time
was found to be dependent on the gas temperature profile and the total flow rate through
the reactor, but almost independent on the coal type. The total flow rate and gas
temperature profile were therefore kept very similar from one reactor condition to another
in order to achieve similar particle residence times. In this project the particle residence
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