Chemical Reaction Engineering Chapter 4, Part 3: Pressure Drop in a Packed Bed Reactor
Algorithm for Isothermal Reactor Design 1.Mole Balance and Design Equation 2.Rate Law 3.Stoichiometry 4.Combine 5.Evaluate
Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR:
Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables:
Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables: Rate Law: Second order in A and irreversible:
Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables: Rate Law: Second order in A and irreversible: Stoichiometry: with T=T 0
Algorithm Analyze the following second order gas phase reaction that occurs isothermally in a PBR: Mole Balance: Must use the differential form of the mole balance to separate variables: Rate Law: Second order in A and irreversible: Stoichiometry: with T=T 0 Combine: Need to find (P/P 0 ) as a function of W (or V if you have a PFR).
Pressure Drop in Packed Bed Reactors
Ergun Equation:
Pressure Drop in Packed Bed Reactors Ergun Equation:
Pressure Drop in Packed Bed Reactors Ergun Equation:
Pressure Drop in Packed Bed Reactors Ergun Equation: Let
Pressure Drop in Packed Bed Reactors Ergun Equation: Let Catalyst Weight: Let and
Multiple Reactions and Pressure Drop
In terms of conversion:
Multiple Reactions and Pressure Drop In terms of conversion:
Multiple Reactions and Pressure Drop In terms of conversion:
Analytical Solution
Separate Integrate
Analytical Solution For gas phase reactions, as the pressure drop increases, the concentation decreases, resulting in a decreased rate of reaction, hence a lower conversion when compared to a reactor without a pressure drop. Separate Integrate
What if… D p and A c change? } } Laminar Turbulent
What if… D p and A c change? } } Laminar Turbulent
What if… D p and A c change? } } Laminar Turbulent
What if… D p and A c change? } } Laminar Turbulent
Polymath Solution