MODELING CHAR OXIDATION AS A FUNCTION OF PRESSURE ...

To study the effects of steam, CO was used in the place of methane, while again
maintaining the total flow rate and temperature profile in the first inch after the injection.
Typical methane flames produce 16-25 mole-% steam in the post-flame gases. CO is an
ideal alternative fuel to reduce steam in the post-flame gases, but as mentioned above,
some hydrogen is necessary to stabilize the CO flame. Therefore, a total absence of
steam in the post-flame gases was not possible. However, by using CO as the fuel, the
steam concentration was reduced from about 17 mole-% to less than 1 mole-%.
The four different char preparation conditions are described in Table A.1, and the
measured temperature profiles for these conditions are given in Table A.2.
Table A.1. Reactor Conditions Used
Condition number #1 #2 #3* #4
Condition name CH4 fuel-rich CH4 fuel-lean CO fuel-rich CO fuel-lean
CH4 (slpm) 4.84 1.52 0 0
CO (slpm) 0 0 16.9 6.41
H2 (slpm) 2.79 4.63 0.37 2
N2 (slpm) 5.41 0 6.46 0
Air (slpm) 38.6 43.7 21.0 40.7
Total flow rate (slpm) 51.6 49.9 44.8 49.1
Quench nitrogen (slpm) 65 65 65 65
Carrier nitrogen (slpm) 0.037 0.037 0.037 0.037
Equivalence ratio 1.37 0.58 1.96 0.49
Post-flame H2O (mole-%) 17.1 16.1 0.69 4.45
Post-flame O2 (mole-%) †
0 8.0 0 9.6
* Flow rates in condition #3 were measured with rotameters while those in other conditions
were measured with mass flow meters.
† Post-flame H 2O and O 2 mole fractions were calculated using EDWRDS code at 1600 K.
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