Effects Of Gas Diffusion Research Articles

Reaction of graphite with carbon dioxide at 1000–1600°C under flow conditions

The reaction of high purity graphite in carbon dioxide was studied at a pressure of 19 torr using flow rates up to 1.8 × 10 20 molecules of carbon dioxide per second through the furnace tube. Below 1350°C external gas diffusion effects were eliminated by the use of small samples and high flow rates. Below 1350°C the reaction followed a chemical controlled reaction mechanism with a heat of activation of 88 ± 5 kcal/mole. Above 1400°C an external gas diffusion controlled mechanism was found for all flow rates. A desorption mechanism was proposed for the chemical controlled region of reaction.

Ablation of graphite in oxygen and air at 1000–1400°C under flow conditions

The ablation of high-purity graphite in oxygen and air atmospheres was studied in the 1000–1400°C temperature range, gas pressures of 2–19 torr and flow rates of 7.6×10 18 to 3.6×10 20 atoms/sec. Gas diffusion effects were eliminated by the use of small samples and fast flow-rates. Very fast ablation rates were observed. The kinetic data are best fitted to a model based on mobile adsorption as the rate limiting step with a heat of activation of 39,000 cal/mole.

Effect of Gas Diffusion in Graphitized Carbon Rods on their Gasification Rate with Carbon Dioxide

Effect of Gas Diffusion in Graphitized Carbon Rods on their Gasification Rate with Carbon Dioxide