Previous models of noncatalytic gas-solid reactions are based primarily on parallelpore representations, thus excluding important topological effects of the porous medium. This paper utilizes network representations and percolation theory to develop expressions for pore closure time and the evolutio
Application of the zone model to multiple noncatalytic fluid-solid reactions
β Scribed by S. Tone; C.Y. Wen
- Publisher
- Elsevier Science
- Year
- 1981
- Tongue
- English
- Weight
- 556 KB
- Volume
- 36
- Category
- Article
- ISSN
- 0009-2509
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β¦ Synopsis
Meet of iotraparticle diffusion on the multiple gas-solid reactions occurring in a porous solid reactant is analyzed by the zone reaction model. In parallel reactions for gases and a consecutive reaction for the solid, the solutions of transient concentration profiles of two solid reactants are given by classifying three zones, viz. reaction zone and reaction-diffusion zone and diffusion zone in the course of the reacfion progression. As an example, the simultaneous reduction-sulfidation of porous iron oxide sorbent in the desulfurization from low BTU coal gases is analyzed by the present model. The Thiele modulus of the reaction governs the behavior of the moving boundary between the reaction zone and the diffusion zone. When the Thiele modulus tends to be infinite, the present model is consistent with the solutions based on the unreacted shrinking core model.
π SIMILAR VOLUMES
Greek letters YE shear rate, s-I P density of liquid, kg/m3 PS density of solids, kg/m3 b thickness of the boundary layer REFERENCES Einenkel, W.-D., 1980, influence of physical properties and equipment design on the homogeneity of suspensions in agitated vessels. User. Chem. Engng 3, 118-124. Fall&
Zinc sulfide pellets sintered at 12OO"C, l000"C, 800"C and 600"C were partially oxidized in a single pellet reactor. Sulfur profiles of these samples were measured using Auger electron spectroscopy (AES) and electron probe microanalysis (EPMA). These profiles showed the coexistence of three zones: a
A mathematical model for the isothermal reaction between a fluid and a porous solid, in pelletgrain form, is studied. First, an analytical derivation of the time for total conversion is presented. Then the differential equations, given as a coupled pair of time-dependent and time-independent equatio