Gas‐solid reactions I: A grain‐cell model for complex reactions

Abstract

A mathematical model has been developed to describe the progress of a consecutive reaction taking place in a porous spherical pellet composed of two solids. Two basic parameters are derived: a Thiele type modulus (H), and a kinetic‐structural parameter (γ). The system of partial differential equations representing the model has been solved numerically, to obtain conversion‐time relations as a function of the physical and kinetic parameters of the system. Highest conversions are obtained at low values of both γ and H.

Multiple Gas–Solid Reactions in a Porous Sorbent Applied to Warm Gas Desulfurization

“…Each grain has subgrains (or spots) similar to materials. 29 Gas molecules collide with the grain surface and leave a spot of solid product on the surface that we can refer to as a subgrain.…”

“…Each particle consists of nonporous grains that cannot merge with each other to form larger grains, thus the number of grains comprising a particle is constant. Each grain has subgrains (or spots) similar to materials . Gas molecules collide with the grain surface and leave a spot of solid product on the surface that we can refer to as a subgrain.…”

“…One of the first models was developed, where each particle contained two types of grains. Furthermore, this model was extended. , An alternative modeling approach represented particles as a number of grains of one type, with grains separated by several types of subgrains. Both the above models allowed for simultaneous reactions as follows …”

Kinetic Study and Mathematical Modeling of the Reduction of ZnO−PbO Mixtures by Methane

“…However, the ZnO−PbO mixture reduction by methane is a complex gas−solid reaction, and the common grain model must be extended for this case. Some references exist in the literature for complex reactions such as the following: (1) the reduction of NiO−Fe 2 O 3 mixtures with hydrogen, (2) the general model for two solids with a gas reaction, (3) the general model for a solid reaction with two gases, (4) the reaction of a gas product with the second solid, and (5) the presence of two solids with different grain sizes in a pellet …”

Modeling of multi gas-solid reactions; effect of bulk environment parameters on solid conversion

“…On the other hand, for complex reaction models, especially with truly multiple reactions and components, no work has yet been reported in the literature. Although there are simplified cases studied, [5][6][7][8] the lack of a comprehensive model in this area is clear.…”