On limiting reaction rate in high-temperature combustion of carbon-graphite materials in the absence of mass transfer effects

✍ Scribed by I.A. Yavorsky

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 689 KB
• Volume: 10
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(72)90072-3

✦ Synopsis

When the total delay time of oxidizer molecules for adsorption, complexing and desorption of reaction products is much less than the mean flight time between collisions a limiting reaction rate is reached which is independent of the properties of the reactant. The total sum of specific gas-kinetic cross-sections of oxidizer molecules arriving at the reaction surface is always smaller than the total reaction surface because of the counter movement of the molecules of the reaction products. On an energetically heterogeneous surface, the limiting reaction rate is reached only under normal reaction conditions ensuring a considerable excess of the mean flight time between collisions of the oxidizer molecules over the total time of chemical reaction on the least reactive sites of the surface. In porous materials, the total reaction rate over the outlet sections of pores is ordinarily equal to or higher than that on sites of the non-porous surface. The method of limiting reaction rates makes it possible to establish the effective depth of penetration of the oxidizer into the pores and, consequently, for each pore size the depth of the normal reaction region.