CRE-Class-7-Summary

MSubbu discussed the relationship between rate constants and temperature, focusing on collision theory and its application in chemical reactions. He explained how to calculate the rate constant ratio using the Arrhenius equation and collision theory, emphasizing the importance of understanding the temperature dependence of reaction rates. MSubbu also touched on the transition state theory and how it relates to temperature, providing a simple way to remember the temperature exponents for different theories.

MSubbu explained the concepts of reaction kinetics and reactor operations, focusing on rate constants, reaction orders, and concentration effects. He discussed how to determine the order of a reaction from the units of the rate constant and explained the difference between batch, continuous, and semi-batch reactor operations. MSubbu also covered the mass and volume balance equations for different reactor types, emphasizing the importance of considering volume changes in gas-phase reactions. He concluded by describing how to calculate concentrations in a plug flow reactor (PFR) and the need to account for volume expansion due to the reaction.

MSubbu discussed stoichiometry and reaction kinetics, focusing on a batch reactor with two parallel first-order reactions. He explained how to calculate the rate constants \(k_1\) and \(k_2\) using given concentration data at \(t=2\) hr, where \(C_A\) is halved and \(C_B\) is twice \(C_C\). MSubbu emphasized the importance of writing mole balances in terms of extent and using these relations to find concentrations, particularly when reactants are not in stoichiometric proportions. 

MSubbu discussed the optimization of a parallel reaction to maximize the formation of product \(F\) by maintaining higher concentrations of \(D\) and lower concentrations of \(E\). He explained that a Plug Flow Reactor (PFR) is the preferred reactor scheme compared to a Continuous Stirred Tank Reactor (CSTR) because it allows for higher average concentrations of \(D\). MSubbu also described a strategy to introduce \(E\) in smaller portions to keep its concentration low while maintaining the required mole ratio of \(D\) to \(E\).

MSubbu discussed the impact of temperature on reaction rates and equilibrium conversions for competitive reactions. He explained that reactions with higher activation energies proceed faster at higher temperatures, while reactions with lower activation energies are favored at lower temperatures. MSubbu also covered the calculation of reactor volume and feed temperature for an adiabatic CSTR, emphasizing the importance of material and energy balances. Finally, he addressed how temperature, pressure, and catalysts affect equilibrium conversions in exothermic reactions, concluding that higher temperatures generally decrease equilibrium conversion, while pressure and catalysts have minimal impact on equilibrium conversion.

MSubbu explained that increasing pressure generally favors reactions, but adding inert gases can dilute the reactants and reduce conversion rates. He emphasized that when high pressure is favorable, keeping the amount of inert gases low helps maintain higher conversion rates. MSubbu concluded that the key to optimizing reactions under favorable high pressure conditions is to minimize the use of inert gases.

MSubbu discussed the calculation of conversion and residence time for a first-order reaction in a batch reactor using an exit age distribution. He explained how to determine the number of tanks in series and the variance of the residence time distribution, which was found to be 48 tanks in series for the given problem. MSubbu also described how to calculate the conversion using a plug flow reactor model and compared it to the continuous stirred tank reactor (CSTR) model. 

MSubbu discussed the relationship between reaction rates and diffusion in porous catalysts, explaining how the Thiele modulus affects reaction effectiveness. He noted that diffusion effects are more significant when the reaction rate is high and the pellet diameter is large. 

MSubbu also announced plans for upcoming classes and discussion sessions, including a peer discussion on CRE scheduled for Saturday and Process Control class starting on Sunday that will cover modeling aspects of unsteady cases. The course is expected to be completed by the 13th or 14th August.