Mass Transfer Combined with Chemical Reactions — Lesson 4

This lesson covers the concept of transport phenomena of non-Newtonian fluids, focusing on mass transfer combined with chemical reactions. It delves into the differences between homogeneous and heterogeneous reactions and their impact on mass flux. The lesson also explains how to solve problems related to mass transfer combined with heterogeneous and homogeneous reactions. It further discusses the concept of diffusion with a homogeneous chemical reaction. The lesson uses illustrative examples such as the absorption of CO2 by concentrated aqueous solution of NaOH and a model for a catalytic reactor to explain these concepts.

Video Highlights

00:15 - Explanation of the concept of diffusive mass transfer and its application in a model for a catalytic reactor.
01:08 - Detailed walkthrough of the mathematical solution for the problem of mass transfer combined with instantaneous reaction.
07:47 - Introduction to the concept of diffusion with a homogeneous chemical reaction.
15:40 - Explanation of the concept of average concentration and its calculation.
29:25 - Conclusion of the lecture with the calculation of the flux.

Key Takeaways

• Homogeneous reactions occur in the entire volume, while heterogeneous reactions take place at specified locations.
• The contribution of the reaction in the mass transfer or flux varies based on the type of reaction.
• In a mass transfer combined with a heterogeneous reaction, the contribution from the reaction comes into the picture as a boundary condition.
• In a mass transfer combined with a homogeneous reaction, the reaction part appears in the balance equation as a source term.
• The concept of diffusion with a homogeneous chemical reaction involves the simultaneous occurrence of diffusion and a homogeneous chemical reaction.