MODELING CHAR OXIDATION AS A FUNCTION OF PRESSURE ...

List of Figures
Figure 2.1. Rate-controlling zones for heterogeneous char oxidation………………….6
Figure 2.2. The effectiveness factor curves for first order and zeroth order reactions
in Cartesian Coordinates..………………………………………………. 19
Figure 4.1. The effectiveness factor curves for first order and zeroth order reactions
in Cartesian Coordinates………………………………………………… 28
Figure 4.2. Effectiveness factor curves for first order and zeroth order reactions in
spherical coordinates……………………………………………………..34
Figure 4.3. The correction function f c plotted as a function of both the general
modulus (M T ) and the observed reaction order in Zone I (m obs )………….38
Figure 5.1. The relationship between KC s and the observed reaction order (n obs ) as
predicted by Eq. (5.13)………..…………………………………………50
Figure 5.2. Illustration of how internal combustion can decrease the particle
diameter………………..……………………………………………….. 60
Figure 7.1. Comparison of predictions of carbon reactivity with graphite flake data
(Ranish and Walker, 1993) obtained as a function of P O2 and T p ………..89
Figure 7.2. Schematic of a pore connected to the surface of a char particle…………..93
Figure 7.3. Schematic of High Pressure Controlled-Profile (HPCP) drop-tube
reactor…………………………………………………………………… 97
Figure 7.4. Comparison of the HP-CBK predictions of reaction rate with large
coal char particle data (Mathias, 1992) as a function of a) V g, b) P O2
(P tot = 0.85 atm), c) P tot (x O2 = 21%), d) P tot (P O2 = 0.18 atm), e) d p,
f) T g…………..…………………………………………………………103
Figure 7.5. The gas temperature profiles for different total pressures……………….108
Figure 7.6. Comparison of HP-CBK predictions of carbon burnouts with
pulverized coal char data (Monson, 1992) at total pressures of 1, 5,
and 10 atm………………………………………………………………110
Figure 7.7. Comparison of HP-CBK predictions of carbon burnouts with
pulverized coal char data (Monson, 1992) at a total pressure of 15 atm.. 110
Figure A.1. Schematic of the flat-flame burner and the particle collection and
separation system……………….………………………………………144
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