mass transfer

A sphere of carbon of radius 10 mm is burned in the presence of air. The pressure is 1 atm and the air is at 1200 K. The density of solid carbon is 2226 kg/m3 and its molecular mass is 12 kg/kmol. The DAB (difussion coefficient) of C02 in air for these conditions is 1.302x10-4 m2/s.

C+ O2----> CO2

Consider molecular counter diffusion and consider for each mol of O2 consumed, 1 mol of CO2 is produced.

a) Develop the propper difussion model for this case

b) Determine the net molar flow rate of C02

c) Determine the molar flow rate of CO2 per area unit considering the initial area of the sphere

d) Determine the time it takes to consumme 1mm of the sphere radius

e) Determine the molar flow rate of O2