6. Pseudo steady state with a heterogeneous reaction. When a coal particle (MW = 12g/mol, = 1280 kg/m3) burns in air (21% oxygen, D O2-air = 10- 4 m2/s), it is converted to CO 2 and CO gas that diffuse from the particle surface. The process is limited by counter diffusion of O 2 and described by the chemical reaction: 3C(s) + 2O 2 (g) 2CO(g) + CO 2(g)

a. State the flux relationships in the gas phase. b. Provide the differential equation that describes the flux of oxygen as a function of radius (N O2,r ). c. Setup the pseudo steady state relationship between total molar flux and mass loss. No need to solve for anything, just describe in your own words what each side of the relationship represents.

R 202 200 CO2