Shrinking core model exhibits inherent limitations to the reactions with a porous particle. Ahn and Choi (2017) indicated that the shrinking core model for a porous pellet would become 837 valid only when the reaction was controlled by inward diffusion (i.e., the reaction proceeded with the core-shell structure). …

What are the limitation of shrinking core model?

Shrinking core model exhibits inherent limitations to the reactions with a porous particle. Ahn and Choi (2017) indicated that the shrinking core model for a porous pellet would become 837 valid only when the reaction was controlled by inward diffusion (i.e., the reaction proceeded with the core-shell structure). …

What is difference between progressive conversion model and shrinking core model?

In most cases, the shrinking-core model (SCM) approximates real particles more closely than does the progressive conversion model (PCM). Comparison of Models with Real Situations. reactant A through the film surrounding the particle to the surface of the solid.

What is progressive conversion model?

Progressive. conversion Model CPcm) Here we lisualize that reactant gas enters and reacts throughout the particle at all times, most likely at different rates at different locations within the particle. They solid reactant is converted continuously. Throughout the particle.

What is the significance of Hatta number in fluid fluid reactions?

The Hatta number (Ha) was developed by Shirôji Hatta, who taught at Tohoku University. It is a dimensionless parameter that compares the rate of reaction in a liquid film to the rate of diffusion through the film.

What is Hatta number and enhancement factor give their usefulness?

What is Hatta modulus?

The Hatta modulus (M H ) is a use- ful parameter that distinguishes reaction rates from diffusive fluxes of substrates, catalytic intermediates or products (see eqn (S14) †).

How do you calculate enhancement?

The SERS enhancement factor (EF) is given by: EF= NvolIsurf/NsurfIvol where Nvol and Nsurf are the number of molecules probed in the aqueous sample and on the SERS substrates, respectively. Ivol and Isurf are the corresponding normal Raman and SERS intensities.

What is the significance of Hatta number in fluid fluid reaction?

What is the enhancement factor?

The enhancement factor E in Eq. ( 10) is defined as the ratio of the liquid mass-transfer coefficients for absorption with and without a chemical reaction.

What is the shrinking core model and the shrinking particle model?

Two models developed in Chapter 9 to describe the kinetics of such reactions are the shrinking-core model (SCM) and the shrinking-particle model (SPM). The SCM applies to particles of constant size during reaction, and we use it for illustrative purposes in this chapter.

Is there a shrinking core model for bulk diffusion?

In this paper a shrinking core model involving the intrinsic chemical reaction and bulk diffusion is developed. A variable-grid, finite-difference method with fully implicit formulation is used for solving the governing equations of the model.

How do you solve the shrinking core problem?

Solution of the entire pseudo-steady state problem (commonly referred to as the shrinking core model) is achieved by analytical integration of eqn. (53) and substitution of the result into eqn. (55), subsequently eliminating the unknown Ca by the use of eqn. (54).

Is the shrinking core the best model of reacting gas-solid systems?

Despite these complications Wen (1968) and Ishida et al. (1971), on the basis of studies of numerous systems, conclude that the shrinking core model is the best simple representation for the majority of reacting gas-solid systems. [Pg.581] A batch of solids of uniform size is treated by gas in a uniform environment.